Synthesis and characterization of chitosan encapsulated zinc oxide (ZnO) nanocomposite and its biological assessment in pepper (Capsicum annuum) as an elicitor for in vitro tissue culture applications

Nanotechnology paves the way for introducing nanoscale fertilizers, pesticides, and elicitors. This study intends to address the synthesis of chitosan/zinc oxide nanocomposite (CS-ZnONP) and its biological assessment in in-vitro conditions. The zinc oxide nanoparticles (ZnONPs) were successfully coated with the chitosan (CS) polymer through a cost-effective approach. Transmission electron microscopy and Fourier transform infrared spectroscopy assessments proved the surface capping of chitosan polymer on ZnONP. The nanocomposite was more capable of improving growth and biomass than the bare ZnONPs. The application of the nanocomposite increased the concentration of chlorophylls (51%), carotenoids (70%), proline (2-fold), and proteins (about 2-fold). The supplementation of culture medium with the nanomaterials upregulated enzymatic antioxidant biomarkers (catalase and peroxidase). The activity of the phenylalanine ammonia-lyase enzyme also displayed a similar significant upward trend in response to the nano-supplements. The CS-ZnONP treatment considerably enhanced the accumulation of alkaloids (60.5%) and soluble phenols (40%), implying stimulation in secondary metabolism. The micropropagation test revealed that the CS-ZnONP treatment improved the organogenesis performance. Overall, the nanocomposite can be considered a highly potent biocompatible elicitor.

Anther and Isolated Microspore Culture in Eggplant (Solanum melongena L.)

Eggplant is one of the five important, worldwide-distributed solanaceous crops. The use of anther culture technology to produce pure, 100% homozygous doubled haploid lines for hybrid seed production is possible since 1982, where the first protocol of wide application to different eggplant materials was published. From then on, different improvements and adaptations to different materials have been made. In parallel, protocols to implement isolated microspore culture technology in eggplant have been developed principally in the last decade, which opens the door for a more efficient DH production in this species. In this chapter, two protocols, one for anther and other for isolated microspore culture in eggplant, are described. Some steps and materials are common to both approaches. A detailed description of each step from is provided.

Triticale Isolated Microspore Culture for Doubled Haploid Production

Here, we describe a method of triticale isolated microspore culture for production of doubled haploid plants via androgenesis. We use this method routinely because it is highly efficient and works well on different triticale genotypes. To force microspores into becoming embryogenic, we apply a 21-day cold pretreatment. The shock of cold facilitates redirecting microspores from their predestined pollen developmental program into the androgenesis pathway. Ovaries are included in our culture methods to help with embryogenesis, and the histone deacytelase inhibitor Trichostatin A (TSA) is added to further improve androgenesis and increase our ability to recover green doubled haploid plants.

Optimization of an improved, efficient and rapid in vitro micropropagation protocol for Petunia hybrida Vilm. Cv. "Bravo"

An efficient protocol for in-vitro propagation of an important ornamental crop, Petunia hybrida Vilm. Cv. “Bravo” was developed. The explants that were used to carry out the experiment were Leaf segments, nodal segments and shoot tips. Nodal segments recorded highest per cent asepsis followed by shoot tips and leaf segments. Asepsis was found to be highest when the explants were sterilized with Fungicide (Carbendazim) 0.02% for the duration of 30 min followed by 0.1% HgCl₂ for duration of 10 min and then ethanol 70% for 10 s. Longer duration of the sterilant treatment showed more necrotic effects on the explants, thus mercuric chloride treatment when given for 5 min proved to be more effective in terms of survival of the explants. Maximum establishment per cent was recorded in Murashige and Skoog (MS) media fortified with BAP (1.5 mg L⁻¹) and IBA (0.5 mg L⁻¹) in shoot tips and nodal segments, i.e. 97.90 and 95.74% respectively. Callus was efficiently induced and developed when PGR amalgamation of BAP (0.1 mg L⁻¹) and 2,4-D (1.5mg L⁻¹) was used. Kinetin at the concentration of 2.0 mg L⁻¹ along with IBA at 0.5mg L⁻¹ recorded highest callus regeneration in both leaf and internodal segment derived callus. Maximum proliferation percent of shoots (97.90%), highest number of shoots (20.50 explant⁻¹) and maximum length of shoot (2.70 cm) was recorded in PGR combination of IBA and BAP both at 0.5 mg L⁻1 concentration level. Rhizogenesis was recorded to be highest in the MS media containing IBA 1.00 mg L⁻¹. Best hardening media which recorded maximum survival per cent 92.50% was noticed on the media formulation comprised of equal ratio of perlite and vermiculite mix, under poly house conditions.

An adventitious agent-free clonal cell line that is highly susceptible to foot -and-mouth disease virus

Porcine LFBKαVβ6 cells have been successfully used for diagnostics and propagation of all FMDV serotypes/subtypes. Unfortunately, after initial characterization, these cells showed contamination with bovine viral diarrhea virus (BVDV), a non-cytopathic adventitious agent. Persistent infection with BVDV could interfere with diagnostic tests and, also prevent consideration for other uses, i.e., vaccine production. In this study, we developed a three-prong methodology to completely remove BVDV from LFBKαVβ6 cells. Combined treatment with siRNA against BVDV NS5A, porcine interferon alpha and ribavirin resulted in the elimination of BVDV, as determined by immunohistochemistry analysis, quantitative RT-PCR and RNA sequencing. Importantly, elimination of BVDV from LFBKαVβ6 did not affect FMDV growth and plaque phenotype from different serotypes isolated and propagated in the clean cell line, newly named MGPK αVβ6-C5. Additionally, isolation of FMDV from field oro-pharyngeal samples, was successful at the same sensitivity as in BVDV-contaminated LFBKαVβ6 cells. Our results identified a direct method to efficiently eliminate BVDV from porcine cells without altering FMDV permissiveness, diagnostic value, or potential for use in vaccine production. Furthermore, these cells may provide an improved platform for diagnostics and propagation of other viruses of interest in the veterinary field and the virology community at large.

Ashwagandha: Advances in plant biotechnological approaches for propagation and production of bioactive compounds

ETHNOPHARMACOLOGICAL RELEVANCE

Withania somnifera is one of the most extensively delved Ayurvedic medicine. Apart from rejuvenation and increasing longevity, it has several other properties such as immunomodulation, anti-cancer, anti-stress and neuroprotection. Because of its prevailing use and increasing demand, it becomes prudent to scientifically evaluate and document both its propagation and production of desired phytoconstituents.

AIM OF THE STUDY

This review aims to highlight the research progress achieved on various biotechnological and tissue culture aspects of Withania somnifera and to cover up-to-date information regarding in-vitro propagation and production of withanolides.

MATERIALS AND METHODS

Significant published studies were identified for the years 2000-2018 using Elsevier-Science Direct, Pubmed and Google scholar and several research studies in our laboratory. Following keywords such as "plant extracts", "in vitro cultures", "callus and suspension culture", "micropropagation", "hairy root cultures" were used. Further, "Withania somnifera", "secondary metabolites specially withanolides", "molecular techniques" and "in vitro conservation" were used to cross-reference the keywords.

RESULTS

Ashwagandha comprises a broad spectrum of phytochemicals with a wide range of pharmacological properties. W. somnifera seeds have reduced viability and germination rates; thus, its regular cultivation method fails to achieve commercial demands mainly for the production of desired phytoconstituents. Cultivation of plant cells/tissues under in vitro conditions and development of various biotechnological strategies will help to build an attractive alternative to provide adequate quality and quantity raw materials. Recently, a large number of in vitro protocols has developed for W. somnifera not only for its propagation but for the production of secondary metabolites as well. Present work highlights a variety of biotechnological strategies both for prompt propagation and production of different bioactive secondary metabolites.

CONCLUSION

The present review focuses on the development and opportunities in various biotechnological approaches to accomplish the global demand of W. somnifera and its secondary metabolites. This review underlines the advances in plant biotechnological approaches for the propagation of W. somnifera and production of its bioactive compounds.

Bioproduction process of natural products and biopharmaceuticals: Biotechnological aspects

Decades of research have been put in place for developing sustainable routes of bioproduction of high commercial value natural products (NPs) on the global market. In the last few years alone, we have witnessed significant advances in the biotechnological production of NPs. The development of new methodologies has resulted in a better understanding of the metabolic flux within the organisms, which have driven manipulations to improve production of the target product. This was further realised due to the recent advances in the omics technologies such as genomics, transcriptomics, proteomics, metabolomics and secretomics, as well as systems and synthetic biology. Additionally, the combined application of novel engineering strategies has made possible avenues for enhancing the yield of these products in an efficient and economical way. Invention of high-throughput technologies such as next generation sequencing (NGS) and toolkits for genome editing Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated 9 (CRISPR/Cas9) have been the game changers and provided unprecedented opportunities to generate rationally designed synthetic circuits which can produce complex molecules. This review covers recent advances in the engineering of various hosts for the production of bioactive NPs and biopharmaceuticals. It also highlights general approaches and strategies to improve their biosynthesis with higher yields in a perspective of plants and microbes (bacteria, yeast and filamentous fungi). Although there are numerous reviews covering this topic on a selected species at a time, our approach herein is to give a comprehensive understanding about state-of-art technologies in different platforms of organisms.

A wake-like state in vitro induced by transmembrane TNF/soluble TNF receptor reverse signaling

Tumor necrosis factor alpha (TNF) has sleep regulatory and brain development roles. TNF promotes sleep in vivo and in vitro while TNF inhibition diminishes sleep. Transmembrane (tm) TNF and the tmTNF receptors (Rs), are cleaved by tumor necrosis factor alpha convertase to produce soluble (s) TNF and sTNFRs. Reverse signaling occurs in cells expressing tmTNF upon sTNFR binding. sTNFR administration in vivo inhibits sleep, thus we hypothesized that a wake-like state in vitro would be induced by sTNFR-tmTNF reverse signaling. Somatosensory cortical neuron/glia co-cultures derived from male and female mice lacking both TNFRs (TNFRKO), or lacking TNF (TNFKO) and wildtype (WT) mice were plated onto six-well multi-electrode arrays. Daily one-hour electrophysiological recordings were taken on culture days 4 through 14. sTNFR1 (0.0, 0.3, 3, 30, 60, and 120 ng/µL) was administered on day 14. A final one-hour recording was taken on day 15. Four measures were characterized that are also used to define sleep in vivo: action potentials (APs), burstiness index (BI), synchronization of electrical activity (SYN), and slow wave power (SWP; 0.25-3.75 Hz). Development rates of these emergent electrophysiological properties increased in cells from mice lacking TNF or both TNFRs compared to cells from WT mice. Decreased SWP, after the three lowest doses (0.3, 3 and 30 ng/µL) of the sTNFR1, indicate a wake-like state in cells from TNFRKO mice. A wake-like state was also induced after 3 ng/µl sTNFR1 treatment in cells from TNFKO mice, which express the TNFR1 ligand, lymphotoxin alpha. Cells from WT mice showed no treatment effects. Results are consistent with prior studies demonstrating involvement of TNF in brain development, TNF reverse signaling, and sleep regulation in vivo. Further, the current demonstration of sTNFR1 induction of a wake-like state in vitro is consistent with the idea that small neuronal/glial circuits manifest sleep- and wake-like states analogous to those occurring in vivo. Finally, that sTNF forward signaling enhances sleep while sTNFR1 reverse signaling enhances a wake-like state is consistent with other sTNF/tmTNF/sTNFR1 brain actions having opposing activities.

Modeling the mature CNS: A predictive screening platform for neurodegenerative disease drug discovery

Background:

Mature primary neuronal cultures are an important model of the nervous system, but limited scalability has been a major challenge in their use for drug discovery of neurodegenerative diseases. This work describes a method for improving scalability through the use of larger format microtiter plates while preserving culture quality.

New Method:

Here we describe a method and quality control procedures for growing embryonic day 18 rat hippocampal/cortical neuronal cultures in 384-well microtiter plates for three weeks in vitro.

Results:

We use these cultures in two assays measuring intracellular lipid vesicle trafficking and synapse density for routine screening of small molecule libraries. Together this culture system and screening platform have successfully identified therapeutics capable of improving cognitive function in transgenic models of Alzheimer’s disease that have advanced to clinical trials, validating their translational applicability.

Comparison with Existing Methods:

Our method enables the growth of healthy, mature neurons in larger format microtiter plates than in traditional primary neuronal culturing protocols, making it ideal for drug screening and mechanism of action studies.

Conclusion:

The predictive capacity of this culture system and screening platform provides a method for rapidly identifying novel disease-modifying neurodegenerative therapeutics.

Microbiological diagnosis of polymicrobial periprosthetic joint infection revealed superiority of investigated tissue samples compared to sonicate fluid generated from the implant surface

OBJECTIVES

In the microbiological diagnosis of periprosthetic joint infection (PJI), there is much discussion about the methodology of obtaining proper specimens, the processing technique, and suitable culture media. This retrospective study was conducted to analyse the accuracy of our culture techniques.

METHODS

Tissue samples and components from 258 patients after revision arthroplasty of the hip, knee, and shoulder were investigated, and the results of tissue cultures (TC) were compared to those of sonicate fluid cultures (SFC). Furthermore, an evaluation was performed of the influence of different culture media on the detection rate.

RESULTS

PJI was confirmed in 186 patients. The overall sensitivity of TC was no different to that of SFC (91.3% vs 90.8%, P = 1). In 153 cases (82.3%), TC and SFC showed concordant positive results. Results were discordant in 33 cases (17.7%). When differentiated according to the type of infection, TC showed significantly better results than SFC in detecting polymicrobial infections (97.0% vs 67.0%, P = 0.004). There were also significant differences between the culture media regarding the yield of microorganisms.

CONCLUSIONS

TC was more effective in detecting co-infections. The best results were obtained using both TC and SFC. The choice of culture media has a significant influence on the quality of results.

Sulfonated cryogel scaffolds for focal delivery in ex-vivo brain tissue cultures

The human brain has unique features that are difficult to study in animal models, including the mechanisms underlying neurodevelopmental and psychiatric disorders. Despite recent advances in human primary brain tissue culture systems, the use of these models to elucidate cellular disease mechanisms remains limited. A major reason for this is the lack of tools available to precisely manipulate a specific area of the tissue in a reproducible manner. Here we report an easy-to-use tool for site-specific manipulation of human brain tissue in culture. We show that line-shaped cryogel scaffolds synthesized with precise microscale dimensions allow the targeted delivery of a reagent to a specific region of human brain tissue in culture. 3-sulfopropyl acrylate (SPA) was incorporated into the cryogel network to yield a negative surface charge for the reversible binding of molecular cargo. The fluorescent dyes BODIPY and DiI were used as model cargos to show that placement of dye loaded scaffolds onto brain tissue in culture resulted in controlled delivery without a burst release, and labelling of specific regions without tissue damage. We further show that cryogels can deliver tetrodotoxin to tissue, inhibiting neuronal function in a reversible manner. The robust nature and precise dimensions of the cryogel resulted in a user-friendly and reproducible tool to manipulate primary human tissue cultures. These easy-to-use cryogels offer an innovate approach for more complex manipulations of ex-vivo tissue.

Datura genome reveals duplications of psychoactive alkaloid biosynthetic genes and high mutation rate following tissue culture

BACKGROUND

Datura stramonium (Jimsonweed) is a medicinally and pharmaceutically important plant in the nightshade family (Solanaceae) known for its production of various toxic, hallucinogenic, and therapeutic tropane alkaloids. Recently, we published a tissue-culture based transformation protocol for D. stramonium that enables more thorough functional genomics studies of this plant. However, the tissue culture process can lead to undesirable phenotypic and genomic consequences independent of the transgene used. Here, we have assembled and annotated a draft genome of D. stramonium with a focus on tropane alkaloid biosynthetic genes. We then use mRNA sequencing and genome resequencing of transformants to characterize changes following tissue culture.

RESULTS

Our draft assembly conforms to the expected 2 gigabasepair haploid genome size of this plant and achieved a BUSCO score of 94.7% complete, single-copy genes. The repetitive content of the genome is 61%, with Gypsy-type retrotransposons accounting for half of this. Our gene annotation estimates the number of protein-coding genes at 52,149 and shows evidence of duplications in two key alkaloid biosynthetic genes, tropinone reductase I and hyoscyamine 6 β-hydroxylase. Following tissue culture, we detected only 186 differentially expressed genes, but were unable to correlate these changes in expression with either polymorphisms from resequencing or positional effects of transposons.

CONCLUSIONS

We have assembled, annotated, and characterized the first draft genome for this important model plant species. Using this resource, we show duplications of genes leading to the synthesis of the medicinally important alkaloid, scopolamine. Our results also demonstrate that following tissue culture, mutation rates of transformed plants are quite high (1.16 × 10- 3 mutations per site), but do not have a drastic impact on gene expression.

A Plaque Reduction Neutralization Test for the Detection of ZIKV-Specific Antibodies

Neutralizing antibodies against Zika virus (ZIKV) are a robust indicator of exposure to ZIKV. Here we describe the plaque reduction neutralization test (PRNT), which quantifies ZIKV-neutralizing antibodies (nAbs) by incubating infectious ZIKV with different dilutions of sera and applying the mixture to a susceptible Vero cell monolayer. After 4 days of incubation, neutral red dye is added to optimize the visualization of plaques caused by ZIKV cytopathic effect. Compared with controls, sera containing nAbs against ZIKV will demonstrate ≥90% reduction in the number of plaques observed. This protocol can be utilized for research applications and serological diagnostic testing with the use of additional controls.

Imaging host-pathogen interactions using epithelial and bacterial cell infection models

The age-old saying, seeing is believing, could not be truer when we think about the value of imaging interactions between epithelial cells and bacterial pathogens. Imaging and culturing techniques have vastly improved over the years, and the breadth and depth of these methods is ever increasing. These technical advances have benefited researchers greatly; however, due to the large number of potential model systems and microscopy techniques to choose from, it can be overwhelming to select the most appropriate tools for your research question. This Review discusses a variety of available epithelial culturing methods and quality control experiments that can be performed, and outlines various options commonly used to fluorescently label bacterial and mammalian cell components. Both light- and electron-microscopy techniques are reviewed, with descriptions of both technical aspects and common applications. Several examples of imaging bacterial pathogens and their interactions with epithelial cells are discussed to provide researchers with an idea of the types of biological questions that can be successfully answered by using microscopy.

Anther Culture in Eggplant (Solanum melongena L.)

For a long time, conventional breeding methods have been used to obtain pure, 100% homozygous lines for hybrid seed production in crops of agronomic interest. However, by doubled haploid technology, it is possible to produce 100% homozygous plants derived from precursors of male gametophytes (androgenesis), to accelerate the production of pure lines, which implies important time and cost savings. In this chapter, a protocol for anther culture in eggplant is described, from donor plant growth conditions to regeneration and acclimation of doubled haploid plants, as well as a description of how to analyze ploidy levels of regenerated plants.

Detergent wash improves vaccinated lymph node handling ex vivo

Lymph nodes (LNs) are essential secondary immune organs where the adaptive immune response is generated against most infections and vaccines. We recently described the use of live ex vivo LN slices to study the dynamics of adaptive immunity. However, when working with reactive lymph nodes from vaccinated animals, the tissues frequently became dislodged from the supportive agarose matrix during slicing, leading to damage that prevented downstream analysis. Because reactive lymph nodes expand into the surrounding adipose tissue, we hypothesized that dislodging was a result of excess lipids on the collagen capsule of the LN, and that a brief wash with a mild detergent would improve LN interaction with the agarose without damaging tissue viability or function. Therefore, we tested the use of digitonin on improving slicing of vaccinated LNs. Prior to embedding, LNs were quickly dipped into a digitonin solution and washed in saline. Lipid droplets were visibly removed by this procedure. A digitonin wash step prior to slicing significantly reduced the loss of LN during slicing from 13 to 75% to 0-25%, without substantial impact on viability. Capture of fluorescent microparticles, uptake and processing of protein antigen, and cytokine secretion in response to a vaccine adjuvant, R848, were all unaffected by the detergent wash. This novel approach will enable ex vivo analysis of the generation of adaptive immune response in LNs in response to vaccinations and other immunotherapies.

Cell membrane rupture: a novel test reveals significant variations among different brands of tissue culture flasks

Objectives

Loss of cytoplasmic molecules including protein controls, due to cell membrane rupture can cause errors and irreproducibility in research data. Previous results have shown that during the washing of a monolayer of cells with a balanced salt solution, the fluid force causes cell membrane rupture on some areas of the flasks/dishes. This fact shows the non-uniformity of the polystyrene surface in terms of cell culture. There is at present no simple test to monitor that surface. This paper presents a novel biologically based assay to determine the degree of heterogeneity of flasks supplied by various manufacturers.

Results

This paper shows that significant variation exists in polystyrene surface heterogeneity among several brands of tissue culture flasks, varying from 4 to 20% of the flask surface. There is also large variability within the production lot of a manufacturer. The assay method involves loading the cells with a cytoplasmic fluorescent marker that is released upon cell membrane rupture. Cell membrane rupture also causes the loss of marker proteins such as GAPDH used in Westernblots. This novel assay method can be used to monitor the batch consistency and the manufacturing process of flasks/dishes. It may also be used to test new biomaterials.

Description of Cohnella zeiphila sp. nov., a bacterium isolated from maize callus cultures

A Gram-stain positive, aerobic, motile, rod-shaped bacterium designated as strain CBP-2801^T was isolated as a contaminant from a culture containing maize callus in Peoria, Illinois, United States. The strain is unique relative to other Cohnella species due to its slow growth and reduced number of sole carbon sources. Phylogenetic analysis using 16S rRNA indicated that strain CBP-2801^T is a Cohnella bacterium and showed the highest similarity to Cohnella xylanilytica (96.8%). Genome-based phylogeny and genomic comparisons based on average nucleotide identity confirmed the strain to be a novel species of Cohnella. Growth occurs at 15-45 °C (optimum 40 °C), pH 5-7 (optimum pH 6) and with 0-1% NaCl. The predominant fatty acids are anteiso-15:0 and 18:1 ω6c. Genome mining for secondary metabolites identified a putative biosynthetic cluster that encodes for a novel lasso peptide. In addition, this study contributes five new genome assemblies of type strains of Cohnella species, a genus with less than 30% of the type strains sequenced. The DNA G + C content is 58.7 mol %. Based on the phenotypic, phylogenetic and biochemical data strain CBP-2801^T represents a novel species, for which the name Cohnella zeiphila sp. nov. is proposed. The type strain is CBP-2801^T (= DSM 111598 = ATCC TSD-230).

Generation of Mouse Eosinophils in Tissue Culture from Unselected Bone Marrow Progenitors

Human eosinophilic leukocytes are found in peripheral blood and tissues at homeostasis and at elevated levels in atopic disorders. As inbred strains of mice (Mus musculus) are currently the models of choice for the study of disease mechanisms in vivo, a full understanding of mouse eosinophils is critical for interpretation of experimental findings. Toward this end, several years ago we presented a protocol for generating mouse eosinophils in tissue culture from unselected bone marrow progenitors (Dyer et al., J Immunol 181: 4004-4009, 2008). This method has been implemented widely and has proven to be effective for generating phenotypically normal eosinophils from numerous mouse strains and genotypes. Here we provide a detailed version of this protocol, along with suggestions and notes for its careful execution. We have also included several protocol variations and suggestions for improvements.

Cryopreservation of Plant Shoot Tips of Potato, Mint, Garlic, and Shallot Using Plant Vitrification Solution 3

Cryopreservation of shoot tips facilitates long-term storage of plant genetic resources which can otherwise only be propagated vegetatively. The vitrification approach using the cryoprotectant plant vitrification solution 3 (PVS3, 50% sucrose and 50% glycerol) is easy to handle, has shown to produce high regrowth percentages in a number of potato, mint, garlic, and shallot accessions, and is, thus, highly suitable for routine cryopreservation of plant genetic resources. In the current chapter, the vitrification procedure is described for potato, mint, garlic, and shallot and includes details about modifications for the different plant species. Special emphasis is given on the preparation of the different culture media, solutions, the culture conditions prior and post-cryopreservation, and the preparation of the shoot tips from different sources. Furthermore, protocols to introduce plants into in vitro culture and methods to estimate cryopreservation success are provided.

Overview of In Vitro and In Vivo Doubled Haploid Technologies

Doubled haploids (DH) have become a powerful tool to assist in different basic research studies, and also in applied research. The principal (but not the only) and routine use of DH by breeding companies is to produce pure lines for hybrid seed production in different crop species. Several decades after the discovery of haploid inducer lines in maize and of anther culture as a method to produce haploid plants from pollen precursors, the biotechnological revolution of the last decades allowed to the development of a variety of approaches to pursue the goal of doubled haploid production. Now, it is possible to produce haploids and DHs in many different species, because when a method does not work properly, there are several others to test. In this chapter, we overview the currently available approaches used to produce haploids and DHs by using methods based on in vitro culture, or involving the in vivo induction of haploid embryo development, or a combination of both.

Transformation of the Plastid Genome in Tobacco Suspension Cell Cultures

Chloroplast transformation has been extremely valuable for the study of plastid biology and gene expression, but the tissue culture methodology involved can be laborious and it can take several months to obtain homoplasmic regenerated plants useful for molecular or physiological studies. In contrast, transformation of tobacco suspension cell plastids provides an easy and efficient system to rapidly evaluate the efficacy of multiple constructs prior to plant regeneration. Suspension cell cultures can be initiated from many cell types, and once established, can be maintained by subculture for more than a year with no loss of transformation efficiency. Using antibiotic selection, homoplasmy is readily achieved in uniform cell colonies useful for comparative gene expression analyses, with the added flexibility to subsequently regenerate plants for in planta studies. Plastids from suspension cells grown in the dark are similar in size and cellular morphology to those in embryogenic culture systems of monocot species, thus providing a useful model for understanding the steps leading to plastid transformation in those recalcitrant species.

Variability of seizure-like activity in an in vitro model of epilepsy depends on the electrical recording method

Background

Hippocampal and cortical slice-based models are widely used to study seizures and epilepsy. Seizure detection and quantification are essential components for studying mechanisms of epilepsy and assessing therapeutic interventions. To obtain meaningful signals and maximize experimental throughput, variability should be minimized. Some electrical recording methods require insertion of an electrode into neuronal tissue, change in slice chemical microenvironment, and transients in temperature and pH. These perturbations can cause acute and long-term alterations of the neuronal network which may be reflected in the variability of the recorded signal.

New method

In this study we investigated the effect of experimental perturbations in three local field potential (LFP) recording methods including substrate micro-wires (s-MWs), multiple electrode arrays (MEAs), and inserted micro wire electrodes (i-MW). These methods enabled us to isolate effects of different perturbations. We used organotypic hippocampal slices (OHCs) as an in-vitro model of posttraumatic epilepsy. To investigate the effect of the disturbances caused by the recording method on the paroxysmal events, we introduced jitter analysis, which is sensitive to small differences in the seizure spike timing.

Results

Medium replacement can introduce long-lasting perturbations. Electrode insertion increased variability on a shorter time scale. OHCs also underwent spontaneous state transitions characterized by transient increases in variability.

Comparison with existing methods

This new method of seizure waveform analysis allows for more sensitive assessment of variability of ictal events than simply measuring seizure frequency and duration.

Conclusion

We demonstrated that some of the variability in OHC recordings are due to experimental perturbations while some are spontaneous and independent of recording method.

Nexus between light and culture media on morphogenesis in Bacopa monnieri and saponin yield thereof

Bacopa monnieri, a well-documented nootropic plant of high commercial global demand had been explored for its effect in alleviating other diseases and symptoms. This is primarily attributed to different phytocompounds present in the plant. One of the major constituents among them are saponins. However, variation in agro-climatic conditions and choice of germplasm often affect the growth rate and yield of phytocompounds that significantly impact the efficacy of the plant and its extract. Tissue culture has been attempted to improve the yield of phytocompounds but is often restricted by higher cost and scalability. Current study explores the role of commercial hydroponic media ‘Leafy 200’ vis-à-vis Murashige and Skoog (MS) media, under different color and intensity of lights, on plant morphogenesis, biomass and saponin yield. Blue light induced more shoot differentiation than normal white light. Statistical studies performed using fractional factorial design showed no significant variations in the yield of saponins among the extracts. The study suggests that hydroponic culture to be a sustainable solution and possible substitute to tissue culture that may be exploited for scalable cultivation of the plant.

Experimental design of a culture approach for corneal endothelial cells of New Zealand white rabbit

The harvesting of corneal endothelial cells (CEC) has received special attention due to its potential as a therapy for corneal blindness. The main challenges are related to the culture media formulation, cellular density at the primary isolation, and the number of passages in which CEC can retain their functional characteristics. To alternate different media formulations to harvest CEC has an impact on the cellular yield and morphology. Therefore, we analyzed four different sequences of growth factor-supplemented Stimulatory (S) and non-supplemented Quiescent (Q) media, upon passages to find the optimal S-Q culture sequence. We assessed cell yield, morphology, procollagen I production, Na⁺/K⁺-ATPase function, and the expression of ZO-1 and Na⁺/K⁺-ATPase. Our results show SQSQ and SQQQ sequences with a balance between an improved cell yield and hexagonal morphology rate. CEC cultured in the SQQQ sequence produced procollagen I, showed Na⁺/K⁺-ATPase function, and expression of ZO-1 and Na⁺/K⁺-ATPase. Our study sets a culture approach to guarantee CEC expansion, as well as functionality for their potential use in tissue engineering and in vivo analyses. Thus, the alternation of S and Q media improves CEC culture. SQQQ sequence demonstrated CEC proliferation and lower the cost implied in SQSQ sequences. We discarded the use of pituitary extract and ROCK inhibitors as essential for CEC proliferation.