Stem cell induction and plant regeneration are affected by medium components in maca (Lepidium meyenii Walp)

BACKGROUND

In medicinal plants, selection, reproduction and preservation of important genotypes are very necessary. Nowadays, using tissue culture and regeneration techniques of medicinal plants under in vitro conditions has been able to proliferate medicinal plants widely, which is much higher than traditional methods of vegetative propagation. Maca (Lepidium meyenii), is an industrial plant whose root is the usable part. Maca has valuable medicinal effects such as sexual enhancement and reproductive power, infertility treatment, improved sperm count and quality, anti-stress, osteoporosis prevention and more.

METHODS AND RESULTS

This study was conducted to induce callus and regeneration of Maca. First, MS medium supplemented with different concentrations of Kinetin, Naphthaleneacetic acid and 2,4-Dichlorophenoxyacetic acid [0.5, 1 and 2 µM respectively] and control were compared for callus induction from root and leaves. After 38 days of incubation, the first callus appeared, after 50 days of callus induction and after 79 days regeneration occurred. The callus induction experiment was performed for the study of the effect of three explants (leaf, stem and root) and seven hormone levels. The regeneration experiment was carried out by studying the effect of three explants (leaf, stem and root) on eight levels of the hormone. The results of data analysis on callus induction showed that the effects of explants, hormones and their interactions on callus induction percentage were highly significant but not significant on callus growth rate. The results of regression analysis showed that explants, hormones and their interactions had no significant effect on regeneration percentage.

CONCLUSION

Based on our results, the best medium for inducing callus was Hormone 2,4-D [2 µM] and Kinetin [0.5 µM], in which the highest percentage of callus induction was in leaf explants (62%). And the lowest were in stem (30%) and root (27%) explants. According to the comparison of the mean, the best environment for regeneration of the environment was 4 µM 6-Benzylaminopurine 2.5 + Thidiazuron, in which the highest percentage of regeneration was in leaf explant (87%) and stem (69%) and the lowest in root explant (12). %).

Developmental trajectory of pluripotent stem cell establishment in Arabidopsis callus guided by a quiescent center-related gene network

In plant tissue culture, callus formation is induced by a high auxin concentration. Among the three cell layers (the outer, middle and inner cell layers) of the callus, pluripotency acquisition in the middle cell layer is required for the potential ability of the callus to regenerate organs. Here, we reveal the developmental trajectory of middle cell layer initiation and maintenance in callus tissue originating from Arabidopsis thaliana hypocotyls. The S phase of the cell cycle is essential for the expression of quiescent center-related SCARECROW (SCR), PLETHORA1 (PLT1) and WUSCHEL-RELATED HOMEOBOX5 (WOX5) genes during the division of callus founder cells to initiate the callus primordium. After callus initiation, SHOOT-ROOT (SHR) proteins move from the inner to the middle cell layer and act together with SCR to promote the expression of PLT1 and WOX5. WOX5 represses the expression of VASCULAR-RELATED NAC-DOMAIN (VND) genes, thereby preventing callus tissue from differentiating into xylem cells. PLT1 and PLT2 directly activate JACKDAW (JKD), which is necessary for pluripotency acquisition in the middle cell layer. We hypothesize that the middle cell layer could have pluripotent stem cell activity and its establishment requires the quiescent center-related SCR-SHR-WOX5-PLT1/2-JKD gene network.

Multiscale analysis of human tissue engineered matrices for next generation heart valve applications

Human tissue-engineered matrices (hTEMs) have been proposed as a promising approach for in situ tissue engineered heart valves (TEHVs). However, there is still a limited understanding on how ECM composition in hTEMs develops over tissue culture time. Therefore, we performed a longitudinal hTEM assessment by 1) multiscale evaluation of hTEM composition during culture time (2, 4, 6-weeks), using (immuno)histology, biochemical assays, and mass spectrometry (LC-MS/MS); 2) analysis of protein pathways involved in ECM development using gene set enrichment analysis (GSEA); and 3) assessment of hTEM mechanical characterization using uniaxial tensile testing. Finally, as a proof-of-concept, TEHVs manufactured using 6-weeks hTEM samples were tested in a pulse duplicator. LC-MS/MS confirmed the tissue culture time-dependent increase in ECM proteins observed in histology and biochemical assays, revealing the most abundant collagens (COL6, COL12), proteoglycans (HSPG2, VCAN), and glycoproteins (FN, TNC). GSEA identified the most represented protein pathways in the hTEM at 2-weeks (mRNA metabolic processes), 4-weeks (ECM production), and 6-weeks (ECM organization and maturation). Uniaxial mechanical testing showed increased stiffness and stress at failure, and reduction in strain over tissue culture time. hTEM-based TEHVs demonstrated promising in vitro performance at both pulmonary and aortic pressure conditions, with symmetric leaflet coaptation and no stenosis. In conclusion, ECM protein abundance and maturation increased over tissue culture time, with consequent improvement of hTEM mechanical characteristics. These findings suggest that longer tissue culture impacts tissue organization, leading to an hTEM that may be suitable for high-pressure applications. STATEMENT OF SIGNIFICANCE: It is believed that the composition of the extracellular matrix (ECM) in the human tissue engineered matrices (hTEM) may favor tissue engineered heart valve (TEHV) remodeling upon implantation. However, the exact protein composition of the hTEM, and how this impacts tissue mechanical properties, remains unclear. Hence, we developed a reproducible rotation-based tissue culture method to produce hTEM samples. We performed a longitudinal assessment using different analytical techniques and mass spectrometry. Our data provided an in-depth characterization of the hTEM proteome with focus on ECM components, their development, and how they may impact the mechanical properties. Based on these results, we manufactured functional hTEM-based TEHVs at aortic-like condition in vitro. These outcomes pose an important step in translating hTEM-based TEHVs into clinics and in predicting their remodeling potential upon implantation.

Identification of biomarkers and outcomes of endocrine disruption in human ovarian cortex using In Vitro Models

Endocrine disrupting chemicals (EDCs) are raising concerns about adverse effects on fertility in women. However, there is a lack of information regarding mechanisms and effects in humans. Our study aims to identify mechanisms of endocrine disruption using two EDCs, diethylstilbestrol (DES) and ketoconazole (KTZ)¹. Human ovarian cortical tissue obtained from Caesarean section patients was exposed to 10^-9 M - 10^-5 M KTZ and 10^-10 M - 10^-6 M DES in vitro for 6 days. Follicle survival and growth were studied via histology analysis and liquid-chromatography-mass spectrometry-based steroid quantification. RNA-sequencing was performed on COV434, KGN, and primary ovarian cells that were exposed for 24 h. Significantly lower unilaminar follicle densities were observed in DES 10^-10 M group, whereas low KTZ exposure reduced secondary follicle density. KTZ 10^-5 M reduced levels of pregnenolone and progesterone. RNA-sequencing revealed that 445 and 233 differentially expressed genes (false discovery rate < 0.1) altogether in DES and KTZ exposed groups. Gene set variation analysis showed that both chemicals modulated pathways that are important for folliculogenesis and steroidogenesis. We selected stearoyl-CoA desaturase (SCD) and 7-dehydrocholesterol reductase (DHCR7) for further validation. Up-regulation of both genes in response to KTZ was confirmed by qPCR and in situ RNA hybridization. Further validation with immunofluorescence focused on the expression of SCD in growing follicles in exposed ovarian tissue. In conclusion, SCD may serve as a potential novel human-relevant biomarker of EDC exposure and effects on ovaries.

Physioxic Culture of Chondrogenic Cells

Cartilage resides under a low oxygen tension within articulating joints. The oxygen tension within cartilage of the knee joint has been measured to be between 2% and 5% oxygen. Although the literature has historically termed this level of oxygen as hypoxia, particularly when doing experiments in vitro in this range, this is actually the physiological oxygen tension experienced in vivo and is more accurately termed physioxia. In general, culture of chondrogenic cells under physioxia has demonstrated a donor-dependent beneficial effect on chondrogenesis, with an upregulation in cartilage genes (SOX9, COL2A1, ACAN) and matrix deposition (sulfated glycosaminoglycans (sGAGs), collagen II). Physioxia also reduces the expression of hypertrophic markers (COL10A1, MMP13). This chapter will outline the methods for the expansion and differentiation of chondrogenic cells under physioxia using oxygen-controlled incubators and glove box environments, with the typical assays used for qualitative and quantitative assessment of chondrogenesis.

Chondrocyte Isolation and Expansion

Chondrocyte isolation requires a combination of enzymatic and mechanical digestion of cartilaginous tissues in order to release the chondrocytes. Extracted primary chondrocytes will then adhere to standard tissue culture plastics, typically in small clusters, over a period of a few days in monolayer culture. Chondrocyte populations are expanded in a basal medium containing serum, supplemented with ascorbic acid, antibiotics, and sometimes antifungal agents and growth factors. Here we describe the standard research grade and good manufacturing practice (GMP) protocols used for the isolation and expansion of chondrocytes by the Oswestry/Keele University Orthopaedic Research (OsKOR) group and John Charnley GMP and MHRA licensed laboratory, both based at the RJAH Orthopaedic Hospital, Oswestry, UK.

An efficient transformation method for tannin-containing sorghum

Background

Tannins are the main bottlenecks restricting the transformation efficiency of plants. Hongyingzi is a special tannin-containing sorghum cultivar used in brewing.

Methods

In this study, a highly efficient microprojectile transformation system for tannin-containing sorghum was successfully exploited using immature embryos (IEs) of Hongyingzi as explants.

Results

Hongyingzi presented two types of calli. Type II calli were found to be the most suitable and effective explants for transformation. After optimization of the geneticin (G418) concentration and tissue culture medium, an average transformation frequency of 27% was achieved. Molecular analyzis showed that all transgenic plants were positive and showed transgenes expression. The inheritance analyzis confirmed that the transgenes could be inherited into the next generation. Thus, we successfully established an efficient transformation system for tannin-containing sorghum and demonstrated the possibility of breaking the restriction imposed by tannins in plants.

Ribonucleoprotein (RNP)-Mediated Allele Replacement in Barley (Hordeum vulgare L.) Leaves

Varietal differences within a species with agronomic importance are often based on minor changes in the genomic sequence. For example, fungus-resistant and fungus-susceptible wheat varieties may vary in only one amino acid. The situation is similar with the reporter genes Gfp and Yfp where two base pairs cause a shift in the emission spectrum from green to yellow. Methods of targeted double-strand break induction now allow this exchange precisely with the simultaneous transfer of the desired repair template. However, these changes rarely lead to a selective advantage that can be used in generating such mutant plants. The protocol presented here allows a corresponding allele replacement at the cellular level using ribonucleoprotein complexes in combination with an appropriate repair template. The efficiencies achieved are comparable to other methods with direct DNA transfer or integration of the corresponding building blocks in the host genome. They are in the range of 35 percent, considering one allele in a diploid organism as barley and using Cas9 RNP complexes.

Ribonucleoprotein (RNP)-Mediated Targeted Mutagenesis in Barley (Hordeum vulgare L.)

The crop species barley is a genetic model for the small grain temperate cereals. Thanks to the availability of whole genome sequence and the development of customizable endonucleases, site-directed genome modification has recently revolutionized genetic engineering. Several platforms have been established in plants, with the most flexible one offered by the clustered regularly interspaced short palindromic repeats (CRISPR) technology. In this protocol, commercially available synthetic guide RNAs (gRNAs), Cas enzymes, or custom-generated reagents are used for targeted mutagenesis in barley. The protocol has been successfully used with immature embryo explants to generate site-specific mutations in regenerants. As the double-strand break-inducing reagents are customizable and can be efficiently delivered, pre-assembled ribonucleoprotein (RNP) complexes allow efficient generation of genome-modified plants.

Toxic effects of trace phenol/guanidine isothiocyanate (P/GI) on cells cultured nearby in covered 96-well plates

BACKGROUND

A mixture of phenol and guanidine isothiocyanate ("P/GI", the principal components of TRIzol™ and similar products) is routinely used to isolate RNA, DNA, and proteins from a single specimen. In time-course experiments of cells grown in tissue culture, replicate wells are often harvested sequentially and compared, with the assumption that in-well lysis and complete aspiration of P/GI has no effect on continuing cultures in nearby wells.

METHODS

To test this assumption, we investigated morphology and function of RAW 264.7 cells (an immortalized mouse macrophage cell line) cultured in covered 96-well plates for 4, 8, or 24 h at varying distances from a single control well or a well into which P/GI had been deposited and immediately aspirated completely.

RESULTS

Time- and distance-dependent disruptions resulting from proximity to a single well containing trace residual P/GI were seen in cell morphology (blebbing, cytoplasmic disruption, and accumulation of intracellular vesicles), cell function (pH of culture medium), and expression of genes related to inflammation (Tnfα) and autophagy (Lc3b). There was no transcriptional change in the anti-apoptotic gene Mcl1, nor the pro-apoptotic gene Hrk, nor in P/GI-unexposed control cultures. LPS-stimulated cells incubated near P/GI had lower expression of the cytokine Il6. These effects were seen as early as 4 h of exposure and at a distance of up to 3 well units from the P/GI-exposed well.

CONCLUSIONS

Exposure to trace residual quantities of P/GI in covered tissue culture plates leads to substantial disruption of cell morphology and function in as little as 4 h, possibly through induction of autophagy but not apoptosis. This phenomenon should be considered when planning time-course experiments in multi-well covered tissue culture plates.

Tissue culture tools for selenium hyperaccumulator Neptunia amplexicaulis for development in phytoextraction

Neptunia amplexicaulis is an herbaceous legume endemic to the Richmond area in central Queensland, Australia and is one of the strongest known Selenium hyperaccumulators on earth, showing significant potential to be utilised in Se phytoextraction applications. Here a protocol was established for in vitro micropropagation of Se hyperaccumulator N. amplexicaulis using nodal segments from in vitro-germinated seedlings. Shoot multiplication was achieved on Murashige and Skoog (MS) basal media supplemented with various concentrations of 6-Benzylaminopurine (BA) (1.0, 2.0, 3.0 mg L^-1) alone or in combination with low levels of Naphthaleneacetic acid (NAA) (0.1, 0.2, 0.3 mg L^-1), with 2.0 mg L^-1 BA + 0.2 mg L^-1 NAA found to be most effective. Elongated shoots were rooted in vitro using NAA, with highest root induction rate of 30% observed at 0.2 mg L^-1 NAA. About 95% of the in vitro rooted shoots survived acclimatization. Clonally propagated plantlets were dosed with selenate/selenite solution and assessed for Se tissue concentrations using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and found to retain their ability to hyperaccumulate. The protocol developed for this study has potential to be optimised for generating clonal plants of N. amplexicaulis for use in research and phytoextraction industry applications.

Biology and biotechnological aspect of sweet potato (Ipomoea batatas L.): a commercially important tuber crop

This review highlights the economic importance of sweet potato and discusses new varieties, agronomic and cultivation practices, pest and disease control efforts, plant tissue culture protocols, and unexplored research areas involving this plant. Abstract Sweet potato is widely consumed in many countries around the world, including India, South Africa and China. Due to its valuable nutritional composition and highly beneficial bioactive compounds, sweet potato is considered a major tuber crop in India. Based on the volume of production, this plant ranks seventh in the world among all food crops. Sweet potato is considered a "Superfood" by the 'Centre for Science in the Public Interest' (CSPI), USA. This plant is mostly propagated through vegetative propagation using vine cuttings or tubers. However, this process is costly, labour-intensive, and comparatively slow. Conventional propagation methods are not able to supply sufficient disease-free planting materials to farmers to sustain steady tuber production. Therefore, there is an urgent need to use various biotechnological approaches, such as cell, tissue, and organ culture, for the large-scale production of healthy and disease-free planting material for commercial purposes throughout the year. In the last five decades, a number of tissue culture protocols have been developed for the production of in vitro plants through meristem culture, direct adventitious organogenesis, callus culture and somatic embryogenesis. Moreover, little research has been done on synthetic seed technology for the in vitro conservation and propagation of sweet potato. The current review comprehensively describes the biology, i.e., plant phenotypic description, vegetative growth, agronomy and cultivation, pests and diseases, varieties, and conventional methods of propagation, as well as biotechnological implementation, of this tuber crop. Furthermore, the explored and unexplored areas of research in sweet potato using biotechnological approaches have been reviewed.

Alcohol: basic and translational research; 15th annual Charles Lieber &1st Samuel French satellite symposium

The present review is based on the research presented at the symposium dedicated to the legacy of the two scientists that made important discoveries in the field of alcohol-induced liver damage: Professors C.S. Lieber and S.W. French. The invited speakers described pharmacological, toxicological and patho-physiological effects of alcohol misuse. Moreover, genetic biomarkers determining adverse drug reactions due to interactions between therapeutics used for chronic or infectious diseases and alcohol exposure were discussed. The researchers presented their work in areas of alcohol-induced impairment in lipid protein trafficking and endocytosis, as well as the role of lipids in the development of fatty liver. The researchers showed that alcohol leads to covalent modifications that promote hepatic dysfunction and injury. We concluded that using new advanced techniques and research ideas leads to important discoveries in science.

Lactate-induced effects on bovine granulosa cells are mediated via PKA signaling

L-lactate acts as a signaling molecule in bovine granulosa cells (GCs). The initiated alterations depend on the transport of L-lactate into the cells via monocarboxylate transporters. In the present study, we further elucidated the intracellular actions of L-lactate and tested whether the PKA signaling pathway is involved. Therefore, we treated cultured bovine GCs with L-lactate and PKA inhibitors H-89 and KT5720, and with an activator of PKA, 6-Bnz-cAMP. L-lactate treatment resulted in decreased estradiol production and downregulation of CYP19A1, FSHR, and LHCGR as well as in the upregulation of the markers of early luteinization PTX3, RGS2, and VNN2. These specific L-lactate effects were almost completely abolished by pre-treatment of the GCs with both inhibitors of PKA signaling. In addition, also the L-lactate-induced upregulation of LDHA and of the monocarboxylate transporters SLC16A1 and SLC16A7 was abolished after PKA inhibition. An activation of the PKA with 6-Bnz-cAMP revealed similar effects on the gene expression like L-lactate alone. In summary, the presented data demonstrate that L-lactate-induced effects on GCs are mediated via PKA signaling thus supporting the role of L-lactate as signaling molecule during the folliculo-luteal transition.

Impact of Valve Culture Positivity on Prognosis in Patients with Infective Endocarditis Who Underwent Valve Surgery

Introduction

Infective endocarditis (IE) is a severe and fatal infection with high in-hospital and overall mortality rates of approximately up to 30%. Valve culture positivity was associated with in-hospital mortality and postoperative complications; however, few studies have analyzed the relationship between valve cultures and overall mortality over a long observation period. This study aimed to compare the association of valve culture positivity with overall mortality in patients with IE who underwent valve surgery.

Methods

A total of 416 IE patients admitted to a tertiary hospital in South Korea from November 2005 to August 2017 were retrospectively reviewed. A total of 202 IE patients who underwent valve surgery and valve culture were enrolled. The primary endpoint was long-term overall mortality. Kaplan–Meier curve and Cox proportional hazards model were used for survival analysis.

Results

The median follow-up duration was 63 (interquartile range, 38–104) months. Valve cultures were positive in 22 (10.9%) patients. The overall mortality rate was 15.8% (32/202) and was significantly higher in valve culture-positive patients (36.4%, p = 0.011). Positive valve culture [hazard ratio (HR) 3.921, p = 0.002], Charlson Comorbidity Index (HR 1.181, p = 0.004), Coagulase-negative staphylococci (HR 4.233, p = 0.001), new-onset central nervous system complications (HR 3.689, p < 0.001), and new-onset heart failure (HR 4.331, p = 0.001) were significant risk factors for overall mortality.

Conclusions

Valve culture positivity is a significant risk factor for long-term overall mortality in IE patients who underwent valve surgery. The importance of valve culture positivity needs to be re-evaluated, as the valve culture positivity rate increases with increasing early surgical intervention.

The stability and sequence cleavage preference of dsRNA are key factors differentiating RNAi efficiency between migratory locust and Asian corn borer

We compared the stability of double-stranded RNA (dsRNA) in each of two body fluids (hemolymph, midgut fluid) and in each of two tissues (integument, midgut), and the uptake of dsRNA in each of two cultured tissues (integument, midgut) between the migratory locust (Locusta migratoria) and the Asian corn borer (Ostrinia furnacalis). We further compared the abundance of putative small interfering RNAs (siRNAs) generated from each of two dsRNAs (dsβ-actin, dsEf1α) and the preference of dsRNA cleavages between the two insect species. Our studies showed a rapid degradation of dsRNA in the midgut fluids of both insect species and in O. furnacalis hemolymph. However, dsRNA remained reasonably stable in L. migratoria hemolymph. When nuclease degradation of dsRNA in cultured tissues was inhibited, dsRNA uptake was not significantly different between the two species. We further showed that the silencing efficiency against target genes was consistent with the abundance of putative siRNAs processed from the dsRNA. In addition, O. furnacalis showed a strong preference in cleaving dsRNA when the nucleotide G was in the position of "1" at 5'-end whereas L. migratoria showed broad spectrum in cleavage sites to generate siRNA. Taken together, our study revealed that silencing efficiency of a target gene by RNAi was directly related to the dsRNA degradation by nucleases and the abundance of siRNAs generated from the dsRNA.

Effects of different light spectra on the slow-grown in vitro storage and quality of banana plantlets cv. Prata Catarina (AAB)

Continues subculturing of in vitro plant subcultures is essential for commercial micropropagation and tissue culture research. In unusual situations, the subcultures can be delayed, and the slow-growth in vitro storage technic could be applied to reduce the loss of plant material. The present study aimed to evaluate the slow-growth in vitro storage of banana plantlets ('Prata Catarina'; group AAB) under different light spectra. Shoot cultures in MS medium without plant growth regulators were maintained under blue (B), red (R), red plus blue (R2B), and white (CW) light spectra (25 °C ± 2 °C; 50 µmol m^-2 s^-1) for up to 140 days. The plantlets maintained under the R, CW, and R2B spectra suffered severe root damage and browning after 140 days of in vitro slow-growth storage (SGS). All plantlets maintained under the B spectrum survived after 140 days of in vitro SGS and showed little browning.

Between Simians and Cell Lines: Rhesus Monkeys, Polio Research, and the Geopolitics of Tissue Culture (1934-1954)

This essay argues that the racialized geopolitics of the rhesus monkey trade conditioned the trajectory of tissue culture in polio research. Rhesus monkeys from north India were important experimental organisms in the American "war against polio" between the 1930s and 1950s. During this period, the National Foundation for Infantile Paralysis (NFIP) expended considerable effort to secure the nonhuman primate for researchers' changing experimental agendas. The NFIP drew on transnational networks to export hundreds of thousands of rhesus monkeys from colonial and later postcolonial India amid the geopolitical upheavals of World War II, the 1947 Partition, and the Cold War. In this essay, I trace how NFIP officials' anxieties about the geopolitics of the monkey trade configured research imperatives in the war against polio. I show how their anxieties more specifically shaped investment in tissue culture techniques as a possible means of obviating dependence on the market in monkeys. I do so by offering a genealogy of the contingent convergence between the use of rhesus monkeys and HeLa cell cultures in the 1954 Salk vaccine trial evaluation. Through this genealogy, I emphasize the geopolitical dimensions of the search for the "right" experimental organisms, tissues, and cells for the "job" of scientific research. The technical transformation of polio research, I argue, relied on the convergence of disparate, racialized biomedical economies.

Overexpression of Oil Palm Early Nodulin 93 Protein Gene (EgENOD93) Enhances In Vitro Shoot Regeneration in Arabidopsis thaliana

EgENOD93 was first identified in a cDNA microarray study of oil palm tissue culture where it was highly expressed in leaf explants with embryogenic potential. Functional characterization via an RNA interference study of its orthologue in Medicago truncatula demonstrated a significant role of this gene in somatic embryo formation. In this study, EgENOD93 was overexpressed in the important model plant Arabidopsis thaliana to investigate the embryogenic potential of EgENOD93 transgenic Arabidopsis explants compared to explants from control plants (pMDC140 and WT). Experiments using leaf explants revealed higher numbers of regenerated shoots at day 27 in all the homozygous transgenic Arabidopsis cultures (Tg01, Tg02 and Tg03) compared to controls. The expression level of EgENOD93 in Arabidopsis cultures was quantified using reverse transcription quantitative real-time PCR (RT-qPCR). The results supported the overexpression of this gene in transgenic Arabidopsis cultures, with 6 and 10 times higher expression of EgENOD93 in callus at Day 9 and Day 20, respectively. Overall, the results support the role of EgENOD93 in the enhancement of shoot regeneration in transgenic Arabidopsis. This together with the previous results observed in oil palm and Medicago truncatula suggests that ENOD93 plays a key role in the induction of somatic embryogenesis. A similarity to early nodulation-like ontogeny is possible.

ER+ Breast Cancer Mammosphere Formation and Analysis

Mammosphere formation assays are a popular and convenient technique in the study of breast cancer by providing an in vitro mechanism by which to study breast cancer stem cell (BCSC) contribution to tumorigenesis, as well as more closely mimicking the three-dimensional tumor microenvironment. In these assays, BCSCs are stimulated to proliferate in low adherence tissue culture dishes and the resulting mammospheres exhibit activation of stem cell-related signaling pathways. Here we describe the process for generating and analyzing mammospheres under varying conditions.

Reverse Genetics for Influenza A and B Viruses Driven by Swine Polymerase I Promoter

Influenza viruses are considered prominent pathogens of humans and animals that are extensively investigated because of public health importance. Plasmid-based reverse genetics is a fundamental tool that facilitates the generation of genetically modified viruses from a cDNA copy. The ability to rescue viruses enables researchers to understand different biological characteristics including IV replication, pathogenesis, and transmission. Furthermore, understanding the biology and ability to manipulate different aspects of the virus can aid in providing a better understanding of the mechanisms of antiviral resistance and development of alternative vaccination strategies. This chapter describes the process of cloning cDNA copies of IAV and IBV RNA segments into a swine polymerase-driven reverse genetics plasmid vector, successful generation of recombinant IVs in swine cells, and propagation of virus in cells or eggs. The swine polymerase reverse genetics system was previously shown to be efficient for de novo rescue of human-, swine-, and avian-origin IAVs and IBV in swine and human origin cell lines utilizing the same protocols discussed in this chapter.

Molecular Farming in Seed Crops: Gene Transfer into Barley (Hordeum vulgare ) and Wheat (Triticum aestivum )

The production of recombinant proteins in seed crops has a long history and cereal grains are now one of the platforms in commercial use. Specific advantages include excellent storage properties, a well-developed endomembrane system with a high biosynthetic capacity and well-established cultivation procedures worldwide. However, the production of transgenic cereals is a time-consuming procedure and the lack of efficient transformation systems is still a significant bottleneck. Barley can be transformed at high efficiency but the protocols are genotype-dependent. Wheat is generally more challenging to transform, but considerable progress has been made in enhancing transformation efficiencies and in controlling transgene expression. In this chapter, we describe and discuss standard procedures for generating transgenic barley and wheat for the production of recombinant proteins.

Standardization of in vitro micropropagation procedure of Oriental Lilium Hybrid Cv. 'Ravenna'

Micropropagation protocol of Oriental Hybrid Lilium cv. Ravenna was developed using bulb scale segments (Basal and Tip) as explants. Surface sterilization of healthy bulb scales with carbendazim 200 ppm for 30 min, then 0.1 percent mercuric chloride for 10 min, then 70% ethyl alcohol for 30 s was superior to all other treatments in recording highest culture asepsis (77.08%) and higher explant survival (86.12%). Explant survival was higher in basal segments (88.54%) compared to tip segments (85.52%). Highest culture establishment was recorded in basal scale segments (68.26%) followed by tip scale segments (55.21%). MS medium augmented with 0.50 mgl⁻¹ Naphthalene acetic acid and 2.0 mgl⁻¹. 6-Benzylamino Purine recorded maximum culture establishment (76.17%), highest bulblet number/explant (5.52) with maximum length of shoots (2.20 cm) and number of leaves (3.39). This treatment combination of growth regulators resulted in highest shoot proliferation (83.33%) along with maximum shoot number (2.41explant⁻¹), shoot length (2.35 cm) and leaf number (5.44) of micro shoots during proliferation stage. Rooting of explants was superior with Indole-3-butyric acid compared to Naphthalene acetic acid. Highest rooting of 92.71% along with maximum number of primary roots shoot⁻¹ (12.06), maximum primary root length (3.17 cm) was documented in Murashige and Skoog medium added with Indole-3-butyric acid 1.50 mgl⁻¹ with best ex vitro survival rate (98.96%) of rooted plantlets during primary hardening in perlite + vermiculite (1:1) mixture.

Callus induction and regeneration in sugarcane under drought stress

Tissue culture methods are useful in assessing the tolerance of various stresses due to the ease of controlling stress under in vitro conditions. This study aimed to investigate the response of sugarcane genotyps to drought stress using calli as a model system. For inducing sugarcane callus, the medium of Murashige and Skoog (MS) was used with different mannitol concentrations (100, 200, and 300 mM) to measure their effects on callus frequency, the day of callus initiation, embryogenic potential, relative growth rate (RGR), water and proline contents, K+ and Na+ contents, as well as the formation of shoot and roots for three sugarcane genotypes (e.g., GT 54-9, G 84-47, and pH 8013). The RAPD-PCR analysis was carried out using five oligonucleotide primers to identify the genetic variation among sugarcane genotypes. The results indicated that the degree of callus proliferation varied from 70 - 86%. The highest value of callus proliferation, PGR, shoot formation was recorded for the genotype GT 54-9 compared to the other two genotypes (G 84-47 and pH 8013). Calli treated with 100 mM mannitol showed the highest RGR, proline and waer contents for the genotype GT 54-9, while, those treated with 300 mM recorded the lowest values of these parameters for the genotype pH 8013. The genotype G 84-47 collected highest Na+ content, while the genotype pH 8013 collected highest K+ content. The results of this study recommend preference for GT 54-9 genotype, which is considered the most promising genotype, showing more tolerance to drought stress based on all studied traits.

Optimized somatic embryogenesis and plant regeneration in elite Argentinian sugarcane (Saccharum spp.) cultivars

Background

Biotechnological breeding of elite sugarcane cultivars is currently limited because of the difficulty of regenerating plants by tissue culture. Here, we report that commercially elite sugarcane genotypes, which are adapted to Argentinian agro-ecological conditions, are capable of being regenerated via indirect somatic embryogenesis. Leaf rolls of five elite genotypes were cultured following two callus induction protocols using different concentrations of 2,4-D as the growth regulator. Embryogenic calluses were regenerated under light conditions. Regenerated plants were subsequently acclimatized in the greenhouse under two acclimatization procedures before being transplanted to the field.

Results

Four of the five genotypes were able to form somatic embryos following the two induction protocols. The variables related to embryogenic callus production were influenced by the interaction between genotype and culture conditions. For plant regeneration, the embryogenic calluses were further cultured on an IBA-supplemented medium, where we observed a high genotype dependence. Calluses from the four cultivars regenerated a good number of plants. With the procedures described here, we obtained more than 90% of well-acclimatized plants both in the greenhouse and in the field.

Conclusions

This protocol provides a simple way to regenerate sugarcane plants through indirect somatic embryogenesis. Also, the results confirm that tissue culture ability is highly genotype-dependent in sugarcane. Our findings suggest that these elite cultivars could be good candidates for biotechnological breeding.