Enrichment of Cryptosporidium parvum from in vitro culture as measured by total RNA and subsequent sequence analysis

Cryptosporidium parvum is an apicomplexan parasite that infects a wide range of hosts including humans. Due to the parasite's quasi-intracellular, intermembrane location on the host cell, it is difficult to purify parasites from in vitro and in vivo infections for molecular studies. We have developed a method to greatly enrich in vitro C. parvum merozoites from host cells. The efficiency of the protocol was assessed with C. parvum (KSU-1 isolate) parasites of different developmental stages isolated following a synchronized infection of HCT-8 host cells. Total RNA was extracted from the samples and used to evaluate the quantity of host cell contamination in enriched parasite fractions. The quality of the RNA was verified using an Agilent BioAnalyzer. cDNA libraries of RNA isolated from 24 and 48 h C. parvum in vitro preparations isolated via this protocol were sequenced at the Broad Institute via an NIH Microbial Sequencing (GSCID) Contract. Cryptosporidium sequences comprised 30% of the cDNA reads, demonstrating significant enrichment.

Using a Teaching Intervention and Calibrated Peer Review™ Diagnostics to Improve Visual Communication Skills

Rice University's bioengineering department incorporates written, oral, and visual communication instruction into its undergraduate curriculum to aid student learning and to prepare students to communicate their knowledge and discoveries precisely and persuasively. In a tissue culture lab course, we used a self- and peer-review tool called Calibrated Peer Review™ (CPR) to diagnose student learning gaps in visual communication skills on a poster assignment. We then designed an active learning intervention that required students to practice the visual communication skills that needed improvement and used CPR to measure the changes. After the intervention, we observed that students performed significantly better in their ability to develop high quality graphs and tables that represent experimental data. Based on these outcomes, we conclude that guided task practice, collaborative learning, and calibrated peer review can be used to improve engineering students' visual communication skills.

Ex vivo culture of human atherosclerotic plaques: A model to study immune cells in atherogenesis

BACKGROUND AND AIMS

The mechanisms that drive atherosclerotic plaque progression and destabilization in humans remain largely unknown. Laboratory models are needed to study these mechanisms under controlled conditions. The aim of this study was to establish a new ex vivo model of human atherosclerotic plaques that preserves the main cell types in plaques and the extracellular components in the context of native cytoarchitecture.

METHODS

Atherosclerotic plaques from carotid arteries of 28 patients undergoing carotid endarterectomy were dissected and cultured. At various time-points, samples were collected and analysed histologically. After enzymatic digestion, single cells were analysed with flow cytometry. Moreover, tissue cytokine production was evaluated.

RESULTS

We optimised the plaque dissection protocol by cutting plaques into circular segments that we cultured on collagen rafts at the medium-air interface, thus keeping them well oxygenated. With this technique, the relative presence of T and B lymphocytes did not change significantly during culture, and the sizes of lymphocyte subsets remained stable after day 4 of culture. Macrophages, smooth muscle cells, and fibroblasts with collagen fibres, as well as T and B lymphocyte subsets and CD16 natural killer cells, remained largely preserved for 19 days of culture, with a continuous production of inflammatory cytokines and chemokines.

CONCLUSIONS

Our new model of ex vivo human atherosclerotic plaques, which preserves the main subsets of immune cells in the context of tissue cytoarchitecture, may be used to investigate important aspects of atherogenesis, in particular, the functions of immune cells under controlled laboratory conditions.

Optogenetic manipulation of anatomical re-entry by light-guided generation of a reversible local conduction block

Aims

Anatomical re-entry is an important mechanism of ventricular tachycardia, characterized by circular electrical propagation in a fixed pathway. It's current investigative and therapeutic approaches are non-biological, rather unspecific (drugs), traumatizing (electrical shocks), or irreversible (ablation). Optogenetics is a new biological technique that allows reversible modulation of electrical function with unmatched spatiotemporal precision using light-gated ion channels. We therefore investigated optogenetic manipulation of anatomical re-entry in ventricular cardiac tissue.

Methods and results

Transverse, 150-μm-thick ventricular slices, obtained from neonatal rat hearts, were genetically modified with lentiviral vectors encoding Ca2+-translocating channelrhodopsin (CatCh), a light-gated depolarizing ion channel, or enhanced yellow fluorescent protein (eYFP) as control. Stable anatomical re-entry was induced in both experimental groups. Activation of CatCh was precisely controlled by 470-nm patterned illumination, while the effects on anatomical re-entry were studied by optical voltage mapping. Regional illumination in the pathway of anatomical re-entry resulted in termination of arrhythmic activity only in CatCh-expressing slices by establishing a local and reversible, depolarization-induced conduction block in the illuminated area. Systematic adjustment of the size of the light-exposed area in the re-entrant pathway revealed that re-entry could be terminated by either wave collision or extinction, depending on the depth (transmurality) of illumination. In silico studies implicated source-sink mismatches at the site of subtransmural conduction block as an important factor in re-entry termination.

Conclusions

Anatomical re-entry in ventricular tissue can be manipulated by optogenetic induction of a local and reversible conduction block in the re-entrant pathway, allowing effective re-entry termination. These results provide distinctively new mechanistic insight into re-entry termination and a novel perspective for cardiac arrhythmia management.

Enhanced micropropagation and tiller formation in sugarcane through pretreatment of explants with thidiazuron (TDZ)

An efficient, simple and commercially applicable protocol for rapid micropropagation of sugarcane has been designed using variety Co 05011. Pretreatment of shoot tip explants with thidiazuron (TDZ) induced high frequency regeneration of shoot cultures with improved multiplication ratio. The highest frequency (80%) of shoot initiation in explants pretreated with 10 mg/l of TDZ was obtained during the study. Maximum 65% shoot cultures could be established from the explants pretreated with TDZ as compared to minimum 40% establishment in explants without pretreatment. The explants pretreated with 10 mg/l of TDZ required minimum 40 days for the establishment of shoot cultures as compared to untreated explants which required 60 days. The highest average number of shoots per culture (19.1) could be obtained from the explants pretreated with 10 mg/l of TDZ, indicating the highest multiplication ratio (1:6). Highest rooting (over 94%) was obtained in shoots regenerated from pretreated explants on ½ strength MS medium containing 5.0 mg/l of NAA and 50 g/l of sucrose within 15 days. Higher number of tillers/clump (15.3) could be counted in plants regenerated from pretreated explants than untreated ones (10.9 tillers/clump) in field condition, three months after transplantation. Molecular analysis using RAPD and DAMD markers suggested that the pretreatment of explants with TDZ did not adversely affect the genetic stability of regenerated plants and maintained high clonal purity.

Efficient and reproducible in vitro regeneration of Solanum lycopersicum and assessment genetic uniformity using flow cytometry and SPAR methods

In the present study, we develop an efficient and reproducible in vitro regeneration system for two cultivars viz., Jamila and Tomaland of Solanum lycopersicum L., an economically important vegetable crop throughout the world. Sterilization of seeds with 2.5% (v/v) NaOCl was found to be most effective, about 97% of seeds germinated on cotton in magenta box moistened with sterile half strength (½)Murashige and Skoog (MS) medium. Regeneration efficiency of cotyledonary leaf (CL) and cotyledonary node (CN) explants derived from 08 days old aseptic seedling were assessed on MS medium supplemented with different concentrations of auxins and cytokinin. CL explants were found more responsive in comparison to CN in both the cultivars. Types of basal media were also assessed and found to have a significant effect on shoot regeneration. Highest regeneration frequency and maximum number of shoots were standardized from CL explants on MS medium supplied with 6-benzyl adenine (BA; 5.0 µM), indole-3-butyric acid (IBA; 2.5 µM) and Kinetin (Kin; 10.0 µM). In vitro regenerated microshoots were rooted on ½MS medium containing 0.5 µM indole-3-butyric acid (IBA). Regenerated plantlets with well-developed roots and shoot system were successfully acclimated to ex vitro condition. Genetic uniformity of tissue culture raised plantlets was first time evaluated using flow cytometry and single primer amplification reaction (SPAR) methods viz., DAMD and ISSR. No significant changes in ploidy level and nuclear DNA content profile were observed between in vitro propagated plants and normal plants of both the cultivars. Similarly, the SPAR analysis also revealed monomorphic banding patterns in regenerated plantlets of S. lycopersicum verifying their genetic uniformity and clonal fidelity. This efficient regeneration system can be used as a fast and reproducible method for genetic transformation of this important vegetable crop.

A novel culture method reveals unique neural stem/progenitors in mature porcine iris tissues that differentiate into neuronal and rod photoreceptor-like cells

Iris neural stem/progenitor cells from mature porcine eyes were investigated using a new protocol for tissue culture, which consists of dispase treatment and Matrigel embedding. We used a number of culture conditions and found an intense differentiation of neuronal cells from both the iris pigmented epithelial (IPE) cells and the stroma tissue cells. Rod photoreceptor-like cells were also observed but mostly in a later stage of culture. Neuronal differentiation does not require any additives such as fetal bovine serum or FGF2, although FGF2 and IGF2 appeared to promote neural differentiation in the IPE cultures. Furthermore, the stroma-derived cells were able to be maintained in vitro indefinitely. The evolutionary similarity between humans and domestic pigs highlight the potential for this methodology in the modeling of human diseases and characterizing human ocular stem cells.

Prescribing antibiotics in diabetic foot infection: what is the role of initial microscopy and culture of tissue samples?. Int Wound J 2017;14:685-690. [PMID: 27696697 PMCID: PMC7950145 DOI: 10.1111/iwj.12674]

The aim of this study was to evaluate the role of microscopy, Gram stain and the culture of tissue samples in the antibiotic treatment of patients with diabetic foot infection. A retrospective review of patients with a diabetic foot infection was undertaken. Data analysed included the severity of infection, antibiotic prescribing patterns, microscopy and culture results. A total of 71 patients were included, from whom 114 tissue samples were collected. Gram stain results were in agreement with final culture results in 45·8% (n = 54) of samples. Overall sensitivity and specificity of the Gram stains were low (74·5% and 69·8%, respectively), although the specificity for Gram-negative rods was high (98·5%). The presence or absence of 'pus cells' on microscopy was a poor predictor of culture results. Empirical prescribing of antibiotics was in accordance with local policy in 31·1% of patients, improving to 86·8 % following culture results. Microscopy, a skilled laboratory procedure, was generally a poor predictor of tissue culture results. However, the presence of Gram-negative rods was suggestive of isolation in the culture of such organisms and could allow the early broadening of antibiotic treatment. Despite initial poor compliance of empirical antibiotic treatment regimens, prescribing was adjusted in light of culture results, suggesting these were important for clinicians.

In Vitro Conservation of Date Palm Somatic Embryos Using Growth-Retardant Conditions

In vitro conservation is carried out to maintain disease-free genetic materials, in a small area, protected against pests, insects, soil problems (alkaline, acidic, excess salinity, lack of organic matter, too dry, or too wet), climatic changes, and high-multiplication potential. A requirement of successful in vitro conservation is that the plants can be regenerated into complete plants rapidly when desired. The current work describes in vitro propagation and conservation techniques employing slow-growth conditions of date palm somatic embryo cultures. Clusters of somatic embryos resulting from an indirect micropropagation protocol are conserved in MS culture medium supplemented with an osmotic agent (sucrose at 90 g/L) combined with a growth-retardant hormone (abscisic acid) at 2 mg/L incubated at low temperature (18 °C) and low light intensity (10 μmol/m²/s). The survival and plant recovery rates are recorded after 10 months. Date palm somatic embryo clusters can be conserved for up to 10 months without subculture with high survival rates. Successfully conserved somatic embryos multiply and germinate to regenerate plants with well-developed shoots and roots, which survive acclimatization and field transfer.

Optimized Direct Organogenesis from Shoot Tip Explants of Date Palm

In vitro propagation is an available alternative to produce uniform and good-quality planting material to establish large-scale date palm cultivation in a short time. This study was carried out to achieve organogenesis and multiplication directly from shoot tips without callus formation, thus avoiding any possibility of undesirable genetic variability among the regenerated plants. The shoot tips explants are cultured on Murashige and Skoog (MS) medium supplemented with 1 mg/L naphthaleneacetic acid (NAA), 1 mg/L naphthoxyacetic acid (NOA), 2.5 mg/L benzyladenine (BA), and 2.5 mg/L isopentenyladenine (2iP). Numerous adventitious buds appeared from the shoot tip explants in darkness after six subcultures at 4-week intervals. Vegetative buds pass through three stages: initiation bud formation, vegetative bud differentiation, and shoot bud proliferation. Shoots are transferred onto medium containing low concentrations of growth regulators for shoot multiplication. The organogenesis protocol described herein consists of six steps: initiation of meristematic buds, multiplication, elongation, rooting, pre-acclimatization, and finally plant acclimatization.

Direct Organogenesis from Immature Female Inflorescence of Date Palm by Gradual Reduction of 2,4-D Concentration

Inflorescences represent an alternative explant source for superior date palm trees, especially those that do not produce offshoots. They provide large numbers of explants free of fungal and bacterial contamination for successful tissue culture initiation. Furthermore, they are characterized by the capacity of plant regeneration within a short time as compared to other explant types. This chapter focuses on the procedures employed for plant regeneration by direct organogenesis using immature female inflorescence explants, including initiation of adventitious buds, differentiation, multiplication, shoot elongation, rooting, and acclimatization. Adding 5 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) into the initiation medium and gradually reducing it to 1 and then to 0.5 mg/L in the subsequent 2 subcultures, respectively, are determining factors in direct adventitious bud formation from the inflorescence. Bud differentiation is obtained on MS medium containing 0.25 mg/L kinetin (Kin), 0.25 mg/L benzyladenine (BA), 0.25 mg/L abscisic acid (ABA), 0.1 mg/L naphthaleneacetic acid (NAA), and 0.2 g/L activated charcoal (AC). Regenerated shoots exhibit sufficient root formation on MS medium supplemented with 2 mg/L indole butyric acid (IBA) and 1 mg/L NAA and subsequent survival in the greenhouse.

Identifying and Controlling Contamination of Date Palm Tissue Cultures

Fungal and bacterial contaminations are major problems facing in vitro date palm (Phoenix dactylifera L.) proliferation. To overcome this problem, we must first identify the fungal (e.g., Alternaria sp., Aspergillus niger, Penicillium sp.) and bacterial (e.g., Pseudomonas sp.) spread in date palm in vitro cultures. Incorporating fungicides (e.g., copper oxychloride, Vitavax T, and Topsin M) or antibiotics (e.g., streptomycin, Banocin, and Bencid D) at 500 mg/L in medium significantly reduces the contamination rate during various stages of in vitro date palm culture. Streptomyces chloramphenicol (pharmacy) is highly effective in reducing the bacterial contamination of date palm cultures to below 10%, as well as enhancing growth vigor.

A novel targeted angiogenesis technique using VEGF conjugated magnetic nanoparticles and in-vitro endothelial barrier crossing

Background

Vascular endothelial growth factor is well known for its angiogenesis potential. The study was performed to determine the possible pro-angiogenic role of magnetic nanoparticles coupled to VEGF in vitro and their capacity to cross an endothelial monolayer. This novel treatment technique for angiogenesis could be potentially useful for therapeutic purposes using magnetic nanoparticles.

Methods

Magnetic nanoparticles (MN) were synthesized and were conjugated with the vascular endothelial growth factor. The particles were tested in vitro in a 2D to 3D culture system. MN was seeded in different positions in relation to an HUVEC spheroid to assess a preferential migration.

To evaluate the MN capacity to cross the endothelial barrier, a confluent monolayer of HUVEC cells was seeded on top of a collagen gel. MN was placed in dissolution on the cell culture media, and the MN position was determined by confocal microscopy for 24 h.

Results

HUVEC spheroids were able to generate a preferential sprouting depending on the MN position. Meanwhile, there was random migration when the MN’s were placed all over the collagen gel and no sprouting when no MN was added. The trans-endothelial migration capacity of the MN was observed after 20 h in culture in the absence of external stimuli.

Conclusion

Here we show in vitro angiogenesis following the distribution of the MN conjugated with growth factors. These nanoparticles could be controlled with a magnet to place them in the ischemic area of interest and speed up vascular recovery. Also, MN has potentials to cross endothelium, opening the doors to a possible intravascular and extravascular treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-017-0643-x) contains supplementary material, which is available to authorized users.

Metabolomics of Rhabdomyosarcoma Cell During Echovirus 30 Infection

Background

Echovirus 30 (E30) causes acute aseptic meningitis. Viral replication requires energy and macromolecular precursors derived from the metabolic network of the host cell. The effect of viral infection within a host cell metabolic activity remains unclear.

Methods

To gain an insight into cell-virus interaction during E30 infection we used a human rhabdomyosarcoma cell line. In a new approach to metabolomics, ^1H NMR was used to measure the level of various cellular metabolites at different times of infection and morphological examination of the cells. Statistical analysis was done by using Confidence interval (CI) 95% and One-way ANOVA test.

Results

The¹H NMR metabolite spectrum signals were observed between mock infected and virus infected cells. Both mock infected and virus infected cells utilized glucose through metabolic pathways and released metabolic end products. Upon infection, the concentration of Alanine, Lactate, Acetate, Glutamate, Tyrosine, Histidine, Phenylalanine, Creatine, Choline and Formate, increased. Interestingly, all of these augmented metabolites were decreased during later stage of infection. The cells showed wide-ranging lipid signals at the end of infection, which correlates with the morphological changes as apoptosis (programmed cell death) of cells was observed. A significant association was found between time interval (12 h, 24 h, and 48 h) and metabolites likewise Alanin, Lactate, Acetate, Glutamate, Tyrosine, Histidine, Phenylalanine, Creatine, Choline and Formate respectively released by cell during infection, which is highly significant (p < 0.01).

Conclusion

Progressive breakdown and utilization of all cellular components were observed as the infection increased. This study is useful for monitoring the cellular metabolic changes during viral infection.

A rapid and efficient in vitro regeneration system for lettuce (Lactuca sativa L.)

BACKGROUND

Successful biotechnological improvement of crop plants requires a reliable and efficient in vitro regeneration system. Lettuce (Lactuca sativa L.), one the most important vegetable crops worldwide, is strongly genotype-dependent in terms of regeneration capacity, limiting the potential for biotechnological improvement of cultivars which show recalcitrance under currently available protocols. The effect of different nutrient sources, plant hormone combinations and activated charcoal supplementation on shoot induction efficiency was evaluated on the cultivar 'RSL NFR', which had previously shown poor regeneration efficiency.

RESULTS

Multiple shoot organogenesis from cotyledon explants was recorded at the highest frequency and speed on Murashige and Skoog regeneration medium supplemented with 200 mg/l of activated charcoal, 3% sucrose, 10 mg/l benzylaminopurine and 0.5 mg/l naphthaleneacetic acid, which induced shoots through direct regeneration in 90.8 ± 7.9% of explants. High shoot induction efficiency was also observed, albeit not quantified, when using this medium on some other cultivars.

CONCLUSIONS

This activated charcoal-containing regeneration medium might offer a rapid and efficient option for direct shoot induction in some lettuce genotypes that do not respond well to common lettuce regeneration protocols. This is also the first report of the effect of activated charcoal in lettuce tissue culture.

Rapid plant regeneration, validation of genetic integrity by ISSR markers and conservation of Reseda pentagyna an endemic plant growing in Saudi Arabia

Reseda pentagyna is the only endemic species among the seven species of the genera Reseda found in Saudi Arabia. Probably no information is available on regeneration by conventional method of regeneration through seeds or cuttings. Therefore, alternative method of tissue culture was attempted to regenerate and multiply the plant. High shoot regeneration (14.44 shoots/explant) was obtained after four weeks, when shoot cuttings cultured on MS containing BA at 1.0 µM. Other cytokinins e.g., Kn, 2iP and TDZ found to be less effective in bud induction and shoot multiplication. Individual shoots were rooted on MS medium supplemented with various auxins at 0.5–5.0 µM concentrations. The IBA (1.5 µM) supplemented MS media induced maximum (83.3%) rooting. The plantlets were acclimatized and hardened under greenhouse conditions in plastic pots containing soil and farm yard manure with 95.0% success. The protocol developed would help to multiply the plant as well as conserve them in natural habitat. This can also be utilized to obtain active constituents for pharmaceutics and genetic manipulations.

Improved micropropagation and in vitro fruiting of Morus indica L. (K-2 cultivar)

A rapid economically viable micropropagation protocol has been developed in the present work for Morus indica L. (K-2 cultivar) utilizing the readily available nodal explants. Explants were established on different plant growth regulators (PGRs) either individually or in combinations. MS medium containing 1 mg L-1 Kinetin (Kin) showed the best shoot multiplication with 4.8 ± 0.23 cm average shoot length and 6.5 ± 0.03 number of internodes. Regenerated shoots were elongated in MS medium supplemented with 1.5 mg L-1 gibberellic acid (GA3). Elongated shoots cultured in full-strength MS medium supplemented with 1 mg L-1 2,4-dichlorophenoxyacetic acid (2,4-D) for one week and then cultured in half-strength MS proved to be more effective in rooting compared to other PGRs in significantly shorter duration. Micropropagated plants transferred to soil fortified with the quarter-strength of MS salts along with humidity regulation process showed 89% survival frequency. In vitro flowering in the regenerated shoots was also observed in the MS medium supplemented with (1.5 mg L-1) Kin and carbon source replaced by commercial sugar cubes. This method can be effectively used for in vitro culture of M. indica in commercial scale owing to its enhanced quality and reduced time frame.

Genotoxicity assessment of high concentrations of 2,4-D, NAA and Dicamba on date palm callus (Phoenix dactylifera L.) using protein profile and RAPD markers

Genetic stability and uniformity of in vitro-derived date palm plants has a major importance to ascertain true-to-typeness of produced plants. The goal of present study was to evaluate the genetic toxicity of different plant growth regulators on date palm callus at initiation stages using protein patterns and RAPD analysis. Date palm offshoots of Hillawii cultivar were dissected, apical meristems were divided into four segments and cultured on callus induction medium containing the plant growth regulators as 2,4-D at 50 and 100 mg/L; NAA at 30 mg/L and Dicamba at 10 mg/L. The changes occurred in protein profile of callus when treated with high concentration of 2,4-D (100 mg/L), including loss of normal fragments (19 and 66 KDa polypeptides in control), as well as, appearance of new fragments, while at low concentration of 2,4-D (50 mg/L) and Dicamba treatment, the protein patterns showed no changes compared to control profile. Similar trends of polymorphisms were obtained with RAPD marker. The high concentration of 2,4-D produced more polymorphic fragments in comparison to control treatment. The DNA profile was identical between 2,4-D at low concentration and control. Dendrograms were generated using similarity indices of protein and RAPD results, and revealed that genetic similarity index was high between 2,4-D treatment at low concentration and control, as separated in one subcluster, followed by Dicamba and NAA, while, the highest genetic distance was obtained between 2,4-D at high concentration and control treatment and separated alone in one cluster.

Application of Hanging Drop Technique for Kidney Tissue Culture

Background/Aims

The hanging drop technique is a well-established method used in culture of animal tissues. However, this method has not been used in adult kidney tissue culture yet. This study was to explore the feasibility of using this technique for culturing adult kidney cortex to study the time course of RNA viability in the tubules and vasculature, as well as the tissue structural integrity.

Methods

In each Petri dish with the plate covered with sterile buffer, a section of mouse renal cortex was cultured within a drop of DMEM culture medium on the inner surface of the lip facing downward. The tissue were then harvested at each specific time points for Real-time PCR analysis and histological studies.

Results

The results showed that the mRNA level of most Na⁺ related transporters and cotransporters were stably maintained within 6 hours in culture, and that the mRNA level of most receptors found in the vasculature and glomeruli were stably maintained for up to 9 days in culture. Paraffin sections of the cultured renal cortex indicated that the tubules began to lose tubular integrity after 6 hours, but the glomeruli and vasculatures were still recognizable up to 9 days in culture.

Conclusions

We concluded that adult kidney tissue culture by hanging drop method can be used to study gene expressions in vasculature and glomeruli.

Biochemical response of hybrid black poplar tissue culture (Populus × canadensis) on water stress

In this study, poplar tissue culture (hybrid black poplar, M1 genotype) was subjected to water stress influenced by polyethyleneglycol 6000 (100 and 200 mOsm PEG 6000). The aim of the research was to investigate the biochemical response of poplar tissue culture on water deficit regime. Antioxidant status was analyzed including antioxidant enzymes, superoxide-dismutase (SOD), catalase (CAT), guiacol-peroxidase (GPx), glutathione-peroxidase (GSH-Px), glutathione-reductase, reduced glutathione, total phenol content, Ferric reducing antioxidant power and DPPH radical antioxidant power. Polyphenol oxidase and phenylalanine-ammonium-lyase were determined as enzymatic markers of polyphenol metabolism. Among oxidative stress parameters lipid peroxidation, carbonyl-proteins, hydrogen-peroxide, reactive oxygen species, nitric-oxide and peroxynitrite were determined. Proline, proline-dehydrogenase and glycinebetaine were measured also as parameters of water stress. Cell viability is finally determined as a biological indicator of osmotic stress. It was found that water stress induced reactive oxygen and nitrogen species and lipid peroxidation in leaves of hybrid black poplar and reduced cell viability. Antioxidant enzymes including SOD, GPx, CAT and GSH-Px were induced but total phenol content and antioxidant capacity were reduced by PEG 6000 mediated osmotic stress. The highest biochemical response and adaptive reaction was the increase of proline and GB especially by 200 mOsm PEG. While long term molecular analysis will be necessary to fully address the poplar potentials for water stress adaptation, our results on hybrid black poplar suggest that glycine-betaine, proline and PDH enzyme might be the most important markers of poplar on water stress and that future efforts should be focused on these markers and strategies to enhance their concentration in poplar.

Oxygen and tissue culture affect placental gene expression

INTRODUCTION

Placental explant culture is an important model for studying placental development and functions. We investigated the differences in placental gene expression in response to tissue culture, atmospheric and physiologic oxygen concentrations.

METHODS

Placental explants were collected from normal term (38-39 weeks of gestation) placentae with no previous uterine contractile activity. Placental transcriptomic expressions were evaluated with GeneChip^® Human Genome U133 Plus 2.0 arrays (Affymetrix).

RESULTS

We uncovered sub-sets of genes that regulate response to stress, induction of apoptosis programmed cell death, mis-regulation of cell growth, proliferation, cell morphogenesis, tissue viability, and protection from apoptosis in cultured placental explants. We also identified a sub-set of genes with highly unstable pattern of expression after exposure to tissue culture. Tissue culture irrespective of oxygen concentration induced dichotomous increase in significant gene expression and increased enrichment of significant pathways and transcription factor targets (TFTs) including HIF1A. The effect was exacerbated by culture at atmospheric oxygen concentration, where further up-regulation of TFTs including PPARA, CEBPD, HOXA9 and down-regulated TFTs such as JUND/FOS suggest intrinsic heightened key biological and metabolic mechanisms such as glucose use, lipid biosynthesis, protein metabolism; apoptosis, inflammatory responses; and diminished trophoblast proliferation, differentiation, invasion, regeneration, and viability.

DISCUSSION

These findings demonstrate that gene expression patterns differ between pre-culture and cultured explants, and the gene expression of explants cultured at atmospheric oxygen concentration favours stressed, pro-inflammatory and increased apoptotic transcriptomic response.

Improved tissue culture conditions for the emerging C4 model Panicum hallii

BACKGROUND

Panicum hallii Vasey (Hall's panicgrass) is a compact, perennial C4 grass in the family Poaceae, which has potential to enable bioenergy research for switchgrass (Panicum virgatum L.). Unlike P. hallii, switchgrass has a large genome, allopolyploidy, self-incompatibility, a long life cycle, and large stature-all suboptimal traits for rapid genetics research. Herein we improved tissue culture methodologies for two inbred P. hallii populations: FIL2 and HAL2, to enable further development of P. hallii as a model C4 plant.

RESULTS

The optimal seed-derived callus induction medium was determined to be Murashige and Skoog (MS) medium supplemented with 40 mg L-1 L-cysteine, 300 mg L-1 L-proline, 3% sucrose, 1 g L-1 casein hydrolysate, 3 mg L-1 2,4-dichlorophenoxyacetic acid (2,4-D), and 45 μg L-1 6-benzylaminopurine (BAP), which resulted in callus induction of 51 ± 29% for FIL2 and 81 ± 19% for HAL2. The optimal inflorescence-derived callus induction was observed on MP medium (MS medium supplemented with 2 g L-1 L-proline, 3% maltose, 5 mg L-1 2,4-D, and 500 μg L-1 BAP), resulting in callus induction of 100 ± 0.0% for FIL2 and 84 ± 2.4% for HAL2. Shoot regeneration rates of 11.5 ± 0.8 shoots/gram for FIL2 and 11.3 ± 0.6 shoots/gram for HAL2 were achieved using seed-induced callus, whereas shoot regeneration rates of 26.2 ± 2.6 shoots/gram for FIL2 and 29.3 ± 3.6 shoots/gram for HAL2 were achieved from inflorescence-induced callus. Further, cell suspension cultures of P. hallii were established from seed-derived callus, providing faster generation of callus tissue compared with culture using solidified media (1.41-fold increase for FIL2 and 3.00-fold increase for HAL2).

CONCLUSIONS

Aside from abbreviated tissue culture times from callus induction to plant regeneration for HAL2, we noted no apparent differences between FIL2 and HAL2 populations in tissue culture performance. For both populations, the cell suspension cultures outperformed tissue cultures on solidified media. Using the methods developed in this work, P. hallii callus was induced from seeds immediately after harvest in a shorter time and with higher frequencies than switchgrass. For clonal propagation, P. hallii callus was established from R1 inflorescences, similar to switchgrass, which further strengthens the potential of this plant as a C4 model for genetic studies. The rapid cycling (seed-to-seed time) and ease of culture, further demonstrate the potential utility of P. hallii as a C4 model plant.

The role of community engagement in the adoption of new agricultural biotechnologies by farmers: the case of the Africa harvest tissue-culture banana in Kenya

Background

The tissue culture banana (TCB) is a biotechnological agricultural innovation that has been adopted widely in commercial banana production. In 2003, Africa Harvest Biotech Foundation International (AH) initiated a TCB program that was explicitly developed for smallholder farmers in Kenya to help them adopt the TCB as a scalable agricultural business opportunity. At the heart of the challenge of encouraging more widespread adoption of the TCB is the question: what is the best way to introduce the TCB technology, and all its attendant practices and opportunities, to smallholder farmers. In essence, a challenge of community or stakeholder engagement (CE).

Results

In this paper, we report the results of a case study of the CE strategies employed by AH to introduce TCB agricultural practices to small-hold farmers in Kenya, and their impact on the uptake of the TCB, and on the nature of the relationship between AH and the relevant community of farmers and other stakeholders. We identified six specific features of CE in the AH TCB project that were critical to its effectiveness: (1) adopting an empirical, “evidence-based” approach; (2) building on existing social networks; (3) facilitating farmer-to-farmer engagement; (4) focusing engagement on farmer groups; (5) strengthening relationships of trust through collaborative experiential learning; and (6) helping farmers to “learn the marketing game”. We discuss the implications of AH’s “values-based” approach to engagement, and how these guiding values functioned as “design constraints” for the key features of their CE strategy. And we highlight the importance of attention to the human dimensions of complex partnerships as a key determinant of successful CE.

Conclusion

Our findings suggest new ways of conceptualizing the relationship between CE and the design and delivery of new technologies for global health and global development.

Inducible Transposition of a Heat-Activated Retrotransposon in Tissue Culture

A transposition of a heat-activated retrotransposon named ONSEN required compromise of a small RNA-mediated epigenetic regulation that includes RNA-directed DNA methylation (RdDM) machinery after heat treatment. In the current study, we analyzed the transcriptional and transpositional activation of ONSEN to better understand the underlying molecular mechanism involved in the maintenance and/or induction of transposon activation in plant tissue culture. We found the transposition of heat-primed ONSEN during tissue culture independently of RdDM mutation. The heat activation of ONSEN transcripts was not significantly up-regulated in tissue culture compared with that in heat-stressed seedlings, indicating that the transposition of ONSEN was regulated independently of the transcript level. RdDM-related genes were up-regulated by heat stress in both tissue culture and seedlings. The level of DNA methylation of ONSEN did not show any change in tissue culture, and the amount of ONSEN-derived small RNAs was not affected by heat stress. The results indicated that the transposition of ONSEN was regulated by an alternative mechanism in addition to the RdDM-mediated epigenetic regulation in tissue culture. We applied the tissue culture-induced transposition of ONSEN to Japanese radish, an important breeding species of the family Brassicaceae. Several new insertions were detected in a regenerated plant derived from heat-stressed tissues and its self-fertilized progeny, revealing the possibility of molecular breeding without genetic modification.

What should be the antibiotic prescription protocol for burn patients admitted in the department of burns, plastic and reconstructive surgery

This is a prospective study with the aim to determine specific patterns of burn wound bacterial colonisation and antimicrobial resistance profiles. There is a high incidence of infections and septicaemia in post-burn patients, which, in turn, are associated with high morbidity and mortality, a fact that compelled us to undertake this study. The study was conducted over a period 11 months, from 1 August 2014 to 30 June 2015, in 50 burn patients admitted in our burn unit. Wound cultures were taken after 72 hours of admission from all the patients, and then, empirical systemic antibiotics were administered. For wound cultures; 1 cubic cm tissue was taken and placed in aerobic and anaerobic culture vials and transported to the microbiology lab under all aseptic precautions as soon as possible. At the time of fever any time after 72 hours of admission, 16 ml of blood was drawn under all aseptic precautions. Both aerobic and anaerobic blood culture vials were filled with 8 ml of blood each and transported to the microbiology lab. The results of culture and sensitivity reports of 50 patients were recorded. The data obtained was analysed using appropriate statistical analytical tests. The most common organism responsible for bacteraemia is Pseudomonas (43%). Most of the strains of organisms isolated were resistant to commonly used antibiotics in the hospital; Pseudomonas was found 100% resistant to a combination of ampicillin + sulbactum, ceftriaxone and was most often sensitive to imipenem, amikacin and vancomycin. Methicillin-resistant Staphylococcus aureus (MRSA) was also found resistant to commonly used antibiotics like ceftriaxone, ampicillin + sulbactum and ceftazidime + calvulanic acid. Linzolid and vancomycin were effective in 83% and 100% cases, respectively. We conclude that similar institution-specific studies should be conducted, and such studies will be helpful in providing useful guidelines for choosing effective empirical therapy that will have a great impact on the prevention of infection and its complications in burn patients because of bacteraemia.

Establishing and maintaining primary cell cultures derived from the ctenophore Mnemiopsis leidyi

We have developed an efficient method for the preparation and maintenance of primary cell cultures isolated from adult Mnemiopsis leidyi, a lobate ctenophore. Our primary cell cultures are derived from tissue explants or enzymatically dissociated cells, and maintained in a complex undefined ctenophore mesogleal serum. These methods can be used to isolate, maintain and visually monitor ctenophore cells to assess proliferation, cellular morphology and cell differentiation in future studies. Exemplar cell types that can be easily isolated from primary cultures include proliferative ectodermal and endodermal cells, motile amebocyte-like cells, and giant smooth muscle cells that exhibit inducible contractile properties. We have also derived 'tissue envelopes' containing sections of endodermal canal surrounded by mesoglea and ectoderm that can be used to monitor targeted cell types in an in vivo context. Access to efficient and reliably generated primary cell cultures will facilitate the analysis of ctenophore development, physiology and morphology from a cell biological perspective.

Bioassay to Study the Attachment of Xanthomonas albilineans on Sugarcane Leaves

Sugarcane (interspecific hybrids of Saccharum species) is an economically important crop that provides 70% of raw table sugar production worldwide and contributes, in some countries, to bioethanol and electricity production. Leaf scald, caused by the bacterial plant pathogen Xanthomonas albilineans, is one of the major diseases of sugarcane. Dissemination of X. albilineans is mainly ensured by contaminated harvesting tools and infected stalk cuttings. However, some strains of this pathogen are transmitted by aerial means and are able to survive as epiphytes on the sugarcane phyllosphere before entering the leaves and causing disease. Here we present a protocol to estimate the capacity of attachment of X. albilineans to sugarcane leaves. Tissue-cultured sugarcane plantlets were immersed in a bacterial suspension of X. albilineans and leaf attachment of X. albilineans was determined by two methods: leaf imprinting (semi-quantitative method) and leaf washing/homogenization (quantitative method). These methods are important tools for evaluating pathogenicity of strains/mutants of the sugarcane leaf scald pathogen.

Primary Culture System for Germ Cells from Caenorhabditis elegans Tumorous Germline Mutants

The Caenorhabditis elegans germ line is an important model system for the study of germ stem cells. Wild-type C. elegans germ cells are syncytial and therefore cannot be isolated in in vitro cultures. In contrast, the germ cells from tumorous mutants can be fully cellularized and isolated intact from the mutant animals. Here we describe a detailed protocol for the isolation of germ cells from tumorous mutants that allows the germ cells to be maintained for extended periods in an in vitro primary culture. This protocol has been adapted from Chaudhari et al., 2016.

Assays to Study the Interaction of Campylobacter jejuni with the Mucosal Surface

Mucosal colonization and overcoming the mucosal barrier are essential steps in the establishment of infection by Campylobacter jejuni. The interaction between C. jejuni and host cells, including binding and invasion, is thought to be the key virulence factor important for pathogenesis of C. jejuni infections in animals or humans. The intestinal mucosal barrier is composed of a polarized epithelium covered by a thick adherent mucus gel layer. There is a requirement for cell culture assays of infection to accurately represent the in vivo mucosal surface. In this chapter, we describe the use of a number of cell culture models and the use of polarized in vitro organ culture to examine the interaction of C. jejuni with mucosal surfaces.

3D Organotypic Culture Model to Study Components of ERK Signaling

Organotypic models are 3D in vitro representations of an in vivo environment. Their complexity can range from an epidermal replica to the establishment of a cancer microenvironment. These models have been used for many years, in an attempt to mimic the structure and function of cells and tissues found inside the body. Methods for developing 3D organotypic models differ according to the tissue of interest and the experimental design. For example, cultures may be grown submerged in culture medium and or at an air-liquid interface. Our group is focusing on an air-liquid interface 3D organotypic model. These cultures are grown on a nylon membrane-covered metal grid with the cells embedded in a Collagen-Matrigel gel. This allows cells to grow in an air-liquid interface to enable diffusion and nourishment from the medium below. Subsequently, the organotypic cultures can be used for immunohistochemical staining of various components of ERK signaling, which is a key player in mediating communication between cells and their microenvironment.

Controlling Hyperhydricity in Date Palm In Vitro Culture by Reduced Concentration of Nitrate Nutrients

Hyperhydricity (or vitrification) is a fundamental physiological disorder in date palm micropropagation. Several factors have been ascribed as being responsible for hyperhydricity, which are related to the explant, medium, culture vessel, and environment. The optimization of inorganic nutrients in the culture medium improves in vitro growth and morphogenesis, in addition to controlling hyperhydricity. This chapter describes a protocol for controlling hyperhydricity during the embryogenic callus stage by optimizing the ratio of nitrogen salts of the Murashige and Skoog (MS) nutrient culture medium. The best results of differentiation from cured hyperhydric callus are obtained using modification at a ratio of NH⁴⁺/NO^3- at 10:15 (825:1425 mg/L) of the MS culture medium to remedy hyperhydric date palm callus and achieve the recovery of normal embryogenic callus and subsequent regeneration of plantlets. Based on the results of this study, nutrient medium composition has an important role in avoiding hyperhydricity problems during date palm micropropagation.

Molecular Characterization of Polio from Environmental Samples: ISSP, The Israeli Sewage Surveillance Protocol

Polioviruses are enteric viruses that cause paralytic poliomyelitis in less than 0.5 % of infections and are asymptomatic in >90 % infections of naïve hosts. Environmental surveillance monitors polio in populations rather than in individuals. When this very low morbidity to infection ratio, drops drastically in highly vaccinated populations, environmental surveillance employing manual or automatic sampling coupled with molecular analysis carried out in well-equipped central laboratories becomes the surveillance method of choice since polioviruses are excreted by infected individuals regardless of whether or not the infection is symptomatic. This chapter describes a high throughput rapid turn-around time method for molecular characterization of polioviruses from sewage. It is presented in five modules: (1) Sewage collection and concentration of the viruses in the sewage; (2) Cell cultures for identification of virus in the concentrated sewage; (3) Nucleic acid extractions directly from sewage and from tissue cultures infected with aliquots of concentrated sewage; (4) Nucleic Acid Amplification for poliovirus serotype identification and intratypic differentiation (discriminating wild and vaccine derived polioviruses form vaccine strains); and (5) Molecular characterization of viral RNA by qRT-PCR, TR-PCR, and Sequence analysis. Monitoring silent or symptomatic transmission of vaccine-derived polioviruses or wild polioviruses is critical for the endgame of poliovirus eradication. We present methods for adapting standard kits and validating the changes for this purpose based on experience gained during the recent introduction and sustained transmission of a wild type 1 poliovirus in Israel in 2013 in a population with an initial IPV vaccine coverage >90 %.

DNA methylation changes and TE activity induced in tissue cultures of barley (Hordeum vulgare L.)

BACKGROUND

In vitro plant regeneration via androgenesis or somatic embryogenesis is capable of inducing (epi)mutations that may affect sexual progenies. While epimutations are associated with DNA methylation, mutations could be due to the movement of transposons. The common notion is that both processes are linked. It is being assumed that demethylation activates transposable elements (TEs). Analysis of methylation changes and their relation with TEs activation in tissue cultures requires uniquely derived donor plants (Ds), their regenerants (Rs) and respective progeny (Ps) that would allow discrimination of processes not related to changes introduced via in vitro cultures. Moreover, a set of methods (RP-HPLC, SSAP, and MSTD) is needed to study whether different TEs families are being activated during in vitro tissue culture plant regeneration and whether their activity could be linked to DNA methylation changes or alternative explanations should be considered.

RESULTS

The in vitro tissue culture plant regeneration in barley was responsible for the induction of DNA methylation in regenerants and conservation of the methylation level in the progeny as shown by the RP-HPLC approach. No difference between andro- and embryo-derived Rs and Ps was observed. The SSAP and MSTD approach revealed that Ds and Rs were more polymorphic than Ps. Moreover, Rs individuals exhibited more polymorphisms with the MSTD than SSAP approach. The differences between Ds, Rs and Ps were also evaluated via ANOVA and AMOVA.

CONCLUSIONS

Stressful conditions during plant regeneration via in vitro tissue cultures affect regenerants and their sexual progeny leading to an increase in global DNA methylation of Rs and Ps compared to Ds in barley. The increased methylation level noted among regenerants remains unchanged in the Ps as indicated via RP-HPLC data. Marker-based experiments suggest that TEs are activated via in vitro tissue cultures and that, independently of the increased methylation, their activity in Rs is greater than in Ps. Thus, the increased methylation level may not correspond to the stabilization of TEs movement at least at the level of regenerants. The presence of TEs variation among Ds that were genetically and epigenetically uniform may suggest that at least some mobile elements may be active, and they may mask variation related to tissue cultures. Thus, tissue cultures may activate some TEs whereas the others remain intact, or their level of movement is changed. Finally, we suggest that sexual reproduction may be responsible for the stabilization of TEs.

Does 2,4-dichlorophenoxyacetic acid (2,4-D) induce genotoxic effects in tissue cultured Allium roots?

2,4-Dichlorophenoxyacetic acid (2,4-D) is a synthetic plant growth regulator that is highly toxic to most broad leaved plants and relatively nontoxic to monocotyledonous plants; is frequently used as weed killer. The study aimed to investigate cytogenetic effects of different concentrations of 2,4-D (0.67, 1.34, 2.01, 2.68, 3.35 and 4.02 mg/L) on Allium cepa bulblets' root tips treated for 24 and 48 h. The results showed six types of structural aberrations: C-mitosis, stickiness, laggards, bridges, fragments and multipolarity that varied numerically compared to control. It significantly affected mitotic index (MI) at 24 and 48 h treatment. In the Allium test, MI increased significantly at three lower concentrations (0.67, 1.34, 2.01 mg/L) after treatment with 2,4-D for 24 h and decreased significantly at higher concentration. Whereas, 2,4-D treatment for 48 h increased MI at all concentrations with significantly decreased MI at the highest concentration. The experiment was extended using comet test that did not reveal significant difference among treatments except for application of 4.02 mg/L 2,4-D for 48 h; where cell damages were verified by comet test. Rest of the concentrations for any duration of time were not damaging and toxic to cells. The results showed, visible mitodepressive action of 4.02 mg/L 2,4-D when treated for 48 h that had tendency to become toxic if the roots had been in touch with 2,4-D for a longer time.

Biology, propagation and utilization of elite coconut varieties (makapuno and aromatics)

Coconut farming is not only a vital agricultural industry for all tropical countries possessing humid coasts and lowlands, but is also a robust income provider for millions of smallholder farmers worldwide. However, due to its longevity, the security of production of this crop suffers significantly from episodes of natural disasters, including cyclone and tsunami, devastating pest and disease outbreaks, while also affected by price competition for the principal products, especially the oil. In order to reduce these pressures, high-value coconut varieties (makapuno and aromatics) have been introduced in some regions, on a limited scale, but with positive outcomes. Even though these two varieties produce fruit with delicious solid or flavoursome liquid endosperm, their distinct biochemical and cellular features unfortunately prevent their in situ germination. In fact, embryo rescue and culture have been developed historically to nurture the embryo under in vitro conditions, enabling effective propagation. In an attempt to provide a comprehensive review featuring these elite coconut varieties, this paper firstly introduces their food values and nutritional qualities, and then discusses the present knowledge of their biology and genetics. Further possibilities for coconut in general are also highlighted, through the use of advanced tissue culture techniques and efficient seedling management for sustainable production of these highly distinct and commercially attractive varieties of coconut.

An optimized method for obtaining adult rat spinal cord motor neurons to be used for tissue culture

BACKGROUND

There is a paucity of detailed methods describing how to harvest and process motor neurons obtained from the adult rat spinal cord.

NEW METHOD

Removal of intra-cardiac perfusion step. The spinal cord is extruded intact from the rat in under 60s post-decapitation then processed without differentiation of ventral and dorsal regions. The temperature during processing was maintained at room temperature (22°C) except during the Papain processing step where the temperature was increased to 30°C.

RESULTS

Cell debris interfered with the counting of cells at the time of plating. Also, cell types could not be identified since they appear rounded structures with no projections. Cell viability counts reduced to 91% and 63% from day 7 to day 14 and days 7-28 respectively. Red blood cell counts in stepped density gradient layers 2 and 3 were low.

COMPARISON WITH EXISTING METHOD(S)

No requirement for intra-cardiac perfusion. No requirement to cool to 4°C post harvesting, No requirement for specialized substrates. Reduces processing time by at least 2h and reduces the potential for processing errors through a reduction in complexity. Procedures are also explained suitable for those new to the culture of primary adult motor neurons.

CONCLUSIONS

Cell viability counts indicate that removal of the perfusion step has a minimal effect on the viability of the cultured nerve cells, which may be due to the reduction in the spinal cord harvesting time and the inclusion of Hibernate based media during extrusion and processing.

Micropropagation and genetic transformation of Tylophora indica (Burm. f.) Merr.: a review

This review provides an in-depth and comprehensive overview of the in vitro culture of Tylophora species, which have medicinal properties. Tylophora indica (Burm. f.) Merr. is a climbing perennial vine with medicinal properties. The tissue culture and genetic transformation of T. indica, which has been extensively studied, is reviewed. Micropropagation using nodal explants has been reported in 25 % of all publications. Leaf explants from field-grown plants has been the explant of choice of independent research groups, which reported direct and callus-mediated organogenesis as well as callus-mediated somatic embryogenesis. Protoplast-mediated regeneration and callus-mediated shoot organogenesis has also been reported from stem explants, and to a lesser degree from root explants of micropropagated plants in vitro. Recent studies that used HPLC confirmed the potential of micropropagated plants to synthesize the major T. indica alkaloid tylophorine prior to and after transfer to field conditions. The genetic integrity of callus-regenerated plants was confirmed by RAPD in a few reports. Tissue culture is an essential base for genetic transformation studies. Hairy roots and transgenic T. indica plants have been shown to accumulate tylophorine suggesting that in vitro biology and transgenic methods are viable ways of clonally producing valuable germplasm and mass producing compounds of commercial value. Further studies that investigate the factors affecting the biosynthesis of Tylophora alkaloids and other secondary metabolites need to be conducted using non-transformed as well as transformed cell and organ cultures.

Anther Culture in Eggplant (Solanum melongena L.)

The technique of in vitro anther culture is the most favorite to incite the production of plants from microspore through direct embryogenesis or regeneration from callus. Anther culture has been employed since 1980s in eggplant to obtain double-haploid plants from microspore derived embryos. From that time it has been refined and widely applied both at commercial level for a fast generation double-haploid parental lines of F1 hybrids, as well as for experimental studies as the complete homozygosis of the microspore-derived plants make more simply the genetic analysis. In this chapter, a step-by-step procedure is reported, taking into consideration all the aspects of the technique, including the growth condition of the anther donor plant, the in vitro regeneration of the androgenetic plantlets, their ploidy analysis, and the colchicine treatment to double the chromosome number of the haploids.

A Troubled Past? Reassessing Ethics in the History of Tissue Culture

Recent books, articles and plays about the 'immortal' HeLa cell line have prompted renewed interest in the history of tissue culture methods that were first employed in 1907 and became common experimental tools during the twentieth century. Many of these sources claim tissue cultures like HeLa had a "troubled past" because medical researchers did not seek informed consent before using tissues in research, contravening a long held desire for self-determination on the part of patients and the public. In this article, I argue these claims are unfair and misleading. No professional guidelines required informed consent for tissue culture during the early and mid twentieth century, and popular sources expressed no concern at the widespread use of human tissues in research. When calls for informed consent did emerge in the 1970s and 1980s, moreover, they reflected specific political changes and often emanated from medical researchers themselves. I conclude by arguing that more balanced histories of tissue culture can make a decisive contribution to public debates today: by refuting a false dichotomy between science and its publics, and showing how ethical concepts such as informed consent arise from a historically specific engagement between professional and social groups.

Reduction of GIGANTEA expression in transgenic Brassica rapa enhances salt tolerance

Here we report the enhancement of tolerance to salt stress in Brassica rapa (Chinese cabbage) through the RNAi-mediated reduction of GIGANTEA ( GI ) expression. Circadian clocks integrate environmental signals with internal cues to coordinate diverse physiological outputs. The GIGANTEA (GI) gene was first discovered due to its important contribution to photoperiodic flowering and has since been shown to be a critical component of the plant circadian clock and to contribute to multiple environmental stress responses. We show that the GI gene in Brassica rapa (BrGI) is similar to Arabidopsis GI in terms of both expression pattern and function. BrGI functionally rescued the late-flowering phenotype of the Arabidopsis gi-201 loss-of-function mutant. RNAi-mediated suppression of GI expression in Arabidopsis Col-0 and in the Chinese cabbage, B. rapa DH03, increased tolerance to salt stress. Our results demonstrate that the molecular functions of GI described in Arabidopsis are conserved in B. rapa and suggest that manipulation of gene expression through RNAi and transgenic overexpression could enhance tolerance to abiotic stresses and thus improve agricultural crop production.

A novel method for investigating Burkholderia cenocepacia infections in patients with cystic fibrosis and other chronic diseases of the airways

BACKGROUND

Burkholderia cenocepacia is a Gram-negative, opportunistic pathogen that is a cause of morbidity and mortality in patients with cystic fibrosis (CF). Research efforts over the past few decades contributed to our understanding of these infections by identifying virulence factors. However, little is known about how this pathogen adapts to the harsh environment found inside the CF airways, which is characterized by a unique mucus containing high concentrations of inflammatory markers. The current study developed a novel model to further investigate this phenomenon.

RESULTS

Monolayers of human A549 lung carcinoma cells (HLCCs) were exposed to a mixture of artificial CF sputum medium (ASMDM) in tissue culture growth medium, and subsequently infected with B. cenocepacia K56-2 for 24 h. The data showed that this model supported B. cenocepacia growth. In addition, consistent with similar studies using current models such as CF airway tissue samples, HLCC viability was reduced by more than 70 % when grown in 60 % ASMDM and infected with B. cenocepacia compared to mock-infected controls and medium alone. Furthermore, the amount of B. cenocepacia cells associated with the HLCC monolayer was more than 10 times greater in 60 % ASMDM when compared to medium controls.

CONCLUSIONS

These findings suggest that HLCC monolayers in 60 % ASMDM serve as a valid alternative to study B. cenocepacia infections in patients with CF, and possibly other chronic diseases of the airways. Furthermore, the results obtained in this study suggest an important role for CF sputum in B. cenocepacia pathogenesis.

Etoposide damages female germ cells in the developing ovary

BACKGROUND

As with many anti-cancer drugs, the topoisomerase II inhibitor etoposide is considered safe for administration to women in the second and third trimesters of pregnancy, but assessment of effects on the developing fetus have been limited. The purpose of this research was to examine the effect of etoposide on germ cells in the developing ovary. Mouse ovary tissue culture was used as the experimental model, thus allowing us to examine effects of etoposide on all stages of germ cell development in the same way, in vitro.

RESULTS

Fetal ovaries from embryonic day 13.5 CD1 mice or neonatal ovaries from postnatal day 0 CD1 mice were cultured with 50-150 ng ml(-1) or 50-200 ng ml(-1) etoposide respectively, concentrations that are low relative to that in patient serum. When fetal ovaries were treated prior to follicle formation, etoposide resulted in dose-dependent damage, with 150 ng ml(-1) inducing a near-complete absence of healthy follicles. In contrast, treatment of neonatal ovaries, after follicle formation, had no effect on follicle numbers and only a minor effect on follicle health, even at 200 ng ml(-1). The sensitivity of female germ cells to etoposide coincided with topoisomerase IIα expression: in the developing ovary of both mouse and human, topoisomerase IIα was expressed in germ cells only prior to follicle formation.

CONCLUSIONS

Exposure of pre-follicular ovaries, in which topoisomerase IIα expression was germ cell-specific, resulted in a near-complete elimination of germ cells prior to follicle formation, with the remaining germ cells going on to form unhealthy follicles by the end of culture. In contrast, exposure to follicle-enclosed oocytes, which no longer expressed topoisomerase IIα in the germ cells, had no effect on total follicle numbers or health, the only effect seen specific to transitional follicles. Results indicate the potential for adverse effects on fetal ovarian development if etoposide is administered to pregnant women when germ cells are not yet enclosed within ovarian follicles, a process that starts at approximately 17 weeks gestation and is only complete towards the end of pregnancy.

Genetic Transformation of Hordeum vulgare ssp. spontaneum for the Development of a Transposon-Based Insertional Mutagenesis System

Domestication and intensive selective breeding of plants has triggered erosion of genetic diversity of important stress-related alleles. Researchers highlight the potential of using wild accessions as a gene source for improvement of cereals such as barley, which has major economic and social importance worldwide. Previously, we have successfully introduced the maize Ac/Ds transposon system for gene identification in cultivated barley. The objective of current research was to investigate the response of Hordeum vulgare ssp. spontaneum wild barley accessions in tissue culture to standardize parameters for introduction of Ac/Ds transposons through genetic transformation. We investigated the response of ten wild barley genotypes for callus induction, regenerative green callus induction and regeneration of fertile plants. The activity of exogenous Ac/Ds elements was observed through a transient assay on immature wild barley embryos/callus whereby transformed embryos/calli were identified by the expression of GUS. Transient Ds expression bombardment experiments were performed on 352 pieces of callus (3-5 mm each) or immature embryos in 4 genotypes of wild barley. The transformation frequency of putative transgenic callus lines based on transient GUS expression ranged between 72 and100 % in wild barley genotypes. This is the first report of a transformation system in H. vulgare ssp. spontaneum.

Impact of molt-disrupting BDE-47 on epidermal ecdysteroid signaling in the blue crab, Callinectes sapidus, in vitro

Polybrominated diphenyl ethers (PBDEs) are environmentally pervasive flame retardants that have been linked with endocrine disruption in a variety of organisms. BDE-47, one of the most prevalent congeners found in aquatic environments, has recently been shown to inhibit crustacean molting, but little is known about the specific mechanism through which molt-inhibition occurs. This study examined whether the inhibitory effect on molting arises from the disruption of hormone signaling in the epidermis using the blue crab, Callinectes sapidus, as the model crustacean. First, we partially sequenced cDNA of N-acetyl-β-glucosaminidase (NAG) from the epidermis, a terminal enzyme in the molting hormone-signaling cascades that is commonly used as the biomarker for ecdysteroid signaling. This partial cDNA sequence was then used to create primers for quantification of NAG gene expression. Then, a new tissue culture technique was developed and dubbed the epidermis-with-exoskeleton (EWE) method, wherein epidermal tissue, along with the overlying exoskeleton, is immersed in a medium of physiologically relevant osmolarity. Using this EWE tissue culture method, we assessed the inducibility of NAG mRNA by 20-hydroxyecdysone (20-HE) in vitro. Exposures to 1μM 20-HE were found to induce NAG mRNA at a significantly higher level than the control. Using NAG expression as a biomarker for ecdysteroid signaling, the effects of BDE-47 were measured. BDE-47 alone at 100nM and a combination of 1μM BDE-47 and 1μM 20-HE were found to significantly increase NAG mRNA. A trend of increasing NAG gene expression in the binary BDE-47 exposure as compared to 1μM BDE-47 and 1μM 20-HE alone is suggestive of a synergistic effect of these two chemicals on ecdysteroid signaling in the cultured epidermis. Discussion on the mechanism for inhibition of crustacean molting by BDE-47 is presented.

Anti-hepatitis C virus potency of a new autophagy inhibitor using human liver slices model

AIM

To evaluate the antiviral potency of a new anti-hepatitis C virus (HCV) antiviral agent targeting the cellular autophagy machinery.

METHODS

Non-infected liver slices, obtained from human liver resection and cut in 350 μm-thick slices (2.7 × 10(6) cells per slice) were infected with cell culture-grown HCV Con1b/C3 supernatant (multiplicity of infection = 0.1) cultivated for up to ten days. HCV infected slices were treated at day 4 post-infection with GNS-396 for 6 d at different concentrations. HCV replication was evaluated by strand-specific real-time quantitative reverse transcription - polymerase chain reaction. The infectivity titers of supernatants were evaluated by foci formation upon inoculation into naive Huh-7.5.1 cells. The cytotoxic effect of the drugs was evaluated by lactate dehydrogenase leakage assays.

RESULTS

The antiviral efficacy of a new antiviral drug, GNS-396, an autophagy inhibitor, on HCV infection of adult human liver slices was evidenced in a dose-dependent manner. At day 6 post-treatment, GNS-396 EC50 was 158 nmol/L without cytotoxic effect (compared to hydroxychloroquine EC50 = 1.17 μmol/L).

CONCLUSION

Our results demonstrated that our ex vivo model is efficient for evaluation the potency of autophagy inhibitors, in particular a new quinoline derivative GNS-396 as antiviral could inhibit HCV infection in a dose-dependent manner without cytotoxic effect.

Constructing Failure: Leonard Hayflick, Biomedicine, and the Problems with Tissue Culture

By examining the use of tissue culture in post-war American biomedicine, this paper investigates how scientists experience and manage failure. I study how Leonard Hayflick forged his new definition of failure and ways of managing it by refuting Alexis Carrel's definition of failure alongside his theory of the immortality of cultured cells. Unlike Carrel, Hayflick claimed that every vertebrate somatic cell should eventually die, unless it transformed into a tumour cell. This claim defined cell death, which had been a problem leading to a laboratory failure, as a normal phenomenon. On the other hand, permanent life, which had been considered a normal cellular characteristic, became a major factor causing scientific failure, since it implied malignant transformation that scientists hoped to control. Hayflick then asserted that his cell strains and method would partly enable scientists to manage this factor-especially that occurred through viral infection-alongside other causes of failure in routine tasks, including bacterial contamination. I argue that the growing biomedical enterprise fostered this work of Hayflick's, which had repercussions in both his career and the uses of cells in diverse investigations. His redefinition of failure in the age of biomedicine resulted in the broad dissemination of his cells, medium, and method as well as his long struggle with the National Institutes of Health (NIH), which caused his temporarily failed career.

Development of an efficient callus proliferation system for Rheum coreanum Nakai, a rare medicinal plant growing in Democratic People's Republic of Korea

A clonal mass propagation to obtain mountainous sources of Rheum coreanum Nakai, a rare medicinal plant in Democratic People’s Republic of Korea was established by rhizome tissue culture. Whole plants were selected and collected as a vigorous individual free from blights and harmful insects among wild plants of R. coreanum grown on the top of Mt. Langrim (1.540 m above the sea) situated at the northern extremity of Democratic People’s Republic of Korea. Induction of the callus was determined using four organs separated from the whole plant and different plant growth regulators. The callus was successfully induced from rhizome explant on MS medium containing 2.4-D (0.2–0.3 mg/l). In the MS medium supplemented with a combination of BAP (2 mg/l) and NAA (0.2 mg/l), single NAA (0.5 mg/l), or IBA (0.5 mg/l), a higher number of shoot, root and plantlets was achieved. The survival rate on the mountainous region of the plantlets successfully acclimatized (100%) in greenhouse reached 95%, and yields of crude drug and contents of active principles were higher than those obtained by sexual and vegetative propagation. This first report of R. coreanum tissue culture provides an opportunity to control extinction threats and an efficient callus proliferation system for growing resources rapidly on a large scale.

Sandalwood: basic biology, tissue culture, and genetic transformation

Sustainable resource preservation of Santalum species that yield commercially important forest products is needed. This review provides an understanding of their basic biology, propagation, hemi-parasitic nature, reproductive biology, and biotechnology. Many species of the genus Santalum (Santalaceae) have been exploited unremittingly for centuries, resulting in the extinction of one and the threatened status of three other species. This reduction in biodiversity of sandalwood has resulted from the commercial exploitation of its oil-rich fragrant heartwood. In a bid to conserve the remaining germplasm, biotechnology provides a feasible, and effective, means of propagating members of this genus. This review provides a detailed understanding of the biological mechanisms underlying the success or failure of traditional propagation, including a synopsis of the process of hemi-parasitism in S. album, and of the suitability of host plants to sustain the growth of seedlings and plants under forestry production. For the mass production of economically important metabolites, and to improve uniformity of essential oils, the use of clonal material of similar genetic background for cultivation is important. This review summarizes traditional methods of sandalwood production with complementary and more advanced in vitro technologies to provide a basis for researchers, conservationists and industry to implement sustainable programs of research and development for this revered genus.

Comparative analysis of bioactive N-alkylamides produced by tissue culture raised versus field plantlets of Spilanthes ciliata using LC-Q-TOF (HRMS)

Spilanthes ciliata (S. ciliata) is a perennial herb of global importance owing to its luscious source of bioactive fatty acid derived amides known as N-alkylamides. It finds application in skin creams, mouth gels and toothpastes. Despite multifaceted applications, a major limitation associated for its commercial application is the scarcity of contamination free plant source, fluctuations in active metabolites due to variation in extraction procedures, and lack of rapid qualitative method for alkylamide profiling. In the current work, attempts were made to 1) optimize conditions for mass propagation of contamination free plants of S. ciliata by tissue culture using leaf discs as explants, 2) establish an optimum extraction ratio of plant/solvent (w/v) for maximum elution of alkylamides and 3) develop a rapid method for qualitative estimation of alkylamide from in vitro raised plants in comparison with that of the field grown counterpart by using LC-Q-TOF (HRMS). To the best of our knowledge, this is the first qualitative report on alkylamide profile of micropropagated whole plant of Spilanthes. The correlation pattern reported in this study may form the basis for using tissue culture raised plantlets of S. ciliata as potential source of bioactive alkylamides on industrial scale.

Is in vitro micrografting a possible valid alternative to traditional micropropagation in Cactaceae? Pelecyphora aselliformis as a case study

Several taxa of Cactaceae are endangered by overcollection for commercial purposes, and most of the family is included in the Convention on International Trade in Endangered Species of Fauna and Flora (CITES). Micropropagation may play a key role to keep the pressure off wild populations and contribute to ex situ conservation of endangered taxa. One of the limits of micropropagation is the species-specific requirement of plant regulators for each taxon and sometimes even for different genotypes. With the micrografting technique the rootstock directly provides the scion with the necessary hormonal requirements. In this paper we present data on in vitro grafting of Pelecyphora aselliformis Ehrenberg, an Appendix I CITES listed species critically endangered and sought after by the horticultural trade, on micropropagated Opuntia ficus-indica Miller. Apical and sub-apical scions of P. aselliformis were used to perform micrografting with a successful rate of 97 and 81 % respectively. Survival rate after ex vivo transfer was 85 %. We hypothesize that this method could be applied to other endangered, slow growing taxa of Cactaceae thus contributing to the conservation of this endangered family.