scholarly journals Genetic Transformation of Apomictic Grasses: Progress and Constraints

2021 ◽  
Vol 12 ◽  
Author(s):  
Andrés M. Bellido ◽  
Eduado D. Souza Canadá ◽  
Hugo R. Permingeat ◽  
Viviana Echenique
Keyword(s):  
Genetic Transformation ◽  
Plant Transformation ◽  
Large Scale ◽  
Crop Improvement ◽  
Current Status ◽  
Grass Species ◽  
Brachiaria Brizantha ◽  
Apomictic Species ◽  
Transformation Methods

The available methods for plant transformation and expansion beyond its limits remain especially critical for crop improvement. For grass species, this is even more critical, mainly due to drawbacks in in vitro regeneration. Despite the existence of many protocols in grasses to achieve genetic transformation through Agrobacterium or biolistic gene delivery, their efficiencies are genotype-dependent and still very low due to the recalcitrance of these species to in vitro regeneration. Many plant transformation facilities for cereals and other important crops may be found around the world in universities and enterprises, but this is not the case for apomictic species, many of which are C4 grasses. Moreover, apomixis (asexual reproduction by seeds) represents an additional constraint for breeding. However, the transformation of an apomictic clone is an attractive strategy, as the transgene is immediately fixed in a highly adapted genetic background, capable of large-scale clonal propagation. With the exception of some species like Brachiaria brizantha which is planted in approximately 100 M ha in Brazil, apomixis is almost non-present in economically important crops. However, as it is sometimes present in their wild relatives, the main goal is to transfer this trait to crops to fix heterosis. Until now this has been a difficult task, mainly because many aspects of apomixis are unknown. Over the last few years, many candidate genes have been identified and attempts have been made to characterize them functionally in Arabidopsis and rice. However, functional analysis in true apomictic species lags far behind, mainly due to the complexity of its genomes, of the trait itself, and the lack of efficient genetic transformation protocols. In this study, we review the current status of the in vitro culture and genetic transformation methods focusing on apomictic grasses, and the prospects for the application of new tools assayed in other related species, with two aims: to pave the way for discovering the molecular pathways involved in apomixis and to develop new capacities for breeding purposes because many of these grasses are important forage or biofuel resources.

scholarly journals Human Pluripotent Stem Cell Culture: Current Status, Challenges, and Advancement

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Sushrut Dakhore ◽  
Bhavana Nayer ◽  
Kouichi Hasegawa
Keyword(s):  
Stem Cells ◽  
Cell Culture ◽  
Pluripotent Stem Cells ◽  
Large Scale ◽  
Embryonic Stem ◽  
Current Status ◽  
Specific Cell ◽  
Therapeutic Applications ◽  
Proliferative Ability

Over the past two decades, human embryonic stem cells (hESCs) have gained attention due to their pluripotent and proliferative ability which enables production of almost all cell types in the human body in vitro and makes them an excellent tool to study human embryogenesis and disease, as well as for drug discovery and cell transplantation therapies. Discovery of human-induced pluripotent stem cells (hiPSCs) further expanded therapeutic applications of human pluripotent stem cells (PSCs). hPSCs provide a stable and unlimited original cell source for producing suitable cells and tissues for downstream applications. Therefore, engineering the environment in which these cells are grown, for stable and quality-controlled hPSC maintenance and production, is one of the key factors governing the success of these applications. hPSCs are maintained in a particular niche using specific cell culture components. Ideally, the culture should be free of xenobiotic components to render hPSCs suitable for therapeutic applications. Substantial efforts have been put to identify effective components, and develop culture conditions and protocols, for their large-scale expansion without compromising on quality. In this review, we discuss different media, their components and functions, including specific requirements to maintain the pluripotent and proliferative ability of hPSCs. Understanding the role of culture components would enable the development of appropriate conditions to promote large-scale, quality-controlled expansion of hPSCs thereby increasing their potential applications.

scholarly journals Degradation of mixed-linkage (1,3;1,4)-β-D-glucan in maize is mediated by the CAL1 licheninase

2020 ◽  
Author(s):  
Florian J Kraemer ◽  
China Lunde ◽  
Moritz Koch ◽  
Benjamin M Kuhn ◽  
Clemens Ruehl ◽  
...  
Keyword(s):  
Cell Walls ◽  
Large Scale ◽  
Enzymatic Digestion ◽  
Causative Mutation ◽  
Grass Species ◽  
Calorie Intake ◽  
Cell Wall Polysaccharide ◽  
Transcript Accumulation ◽  
Altered Cell

The presence of mixed-linkage (1,3;1,4)-β-D-glucan (MLG) in plant cell walls is a key feature of grass species such as cereals - the main source of calorie intake for humans and cattle. Accumulation of this polysaccharide involves the coordinated regulation of biosynthetic and metabolic machineries. While several components of the MLG biosynthesis machinery have been identified in diverse plant species, degradation of MLG is poorly understood. A large-scale forward genetic maize screen for mutants with altered cell wall polysaccharide structural properties resulted in the identification of candy-leaf1 (cal1). Cell walls of CAL1-deficient plants contain higher amounts of MLG in several tissues, including adult leaves and senesced organs, where only trace amounts of MLG are usually detected. In addition, cal1 plants exhibit increased saccharification yields upon enzymatic digestion. Stacking cal1 with lignin-deficient mutations results in synergistic saccharification increases. Identification of the causative mutation revealed that CAL1 encodes a GH17 licheninase. Maize plants overexpressing CAL1 exhibit a 90% reduction in MLG content, indicating that CAL1 is not only required, but its expression sufficient to degrade MLG. CAL1 specifically hydrolyzes (1,3;1,4)-β-D-Glucans in vitro, and the single CAL1E262K amino acid substitution is able to block all detectable activity. Time profiling experiments indicate that wall MLG content is modulated during day/night cycles inversely correlating with CAL1 transcript accumulation. This cycling is absent in the cal1 mutant, suggesting that the mechanism involved requires MLG degradation that may in turn regulate CAL1 gene expression.

scholarly journals CURRENT STATUS OF TRANSGENIC COTTON-UTILITY OF GENOTYPE INDEPENDENT IN PLANTA APPROACHES FOR THE GENERATION OF TRANSGENICS

2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Kesiraju Karthik
Keyword(s):  
Tissue Culture ◽  
In Vitro Regeneration ◽  
Crop Improvement ◽  
Transgenic Cotton ◽  
Current Status ◽  
In Planta ◽  
Biotic And Abiotic Stresses ◽  
Independent Manner ◽  
Gossypium Spp

Cotton (Gossypium spp.), is a mercantile crop plant is grown for its fluffy fiber and cotton seed oil in around 70 countries worldwide. Cotton is an economically important crop, shows erratic productivity under rain feed conditions; it is bogged down with many biotic and abiotic stresses. Due to lack of resistant germplasm, crop improvement through conventional breeding practices has been lagging. Genetic engineering offers numerous protocols to engineer plants to overcome stress. Biotechnological intervention for cotton improvement has begun three decades ago. The recalcitrance of cotton to tissue culture has been the major constraint for in vitro regeneration. Alternate methods that evade tissue culture regeneration steps have thus been envisaged. Till date there are very few standardized protocols that can be employed to develop transgenics in a genotype independent manner. Thus, genotype independent in planta transformation strategies have gained momentum in the present days, but reproducibility of reported protocols remains an amigna in many cases. In planta transformations holds prominence due to viability and ease in generation of transgenic cotton plants with in less time. This review focuses on grouping efforts made by different research groups in this senior. Several reports and standardizations have been focused that reports development of transgenic cotton.

scholarly journals Requirements for multi-level systems pharmacology models to reach end-usage: the case of type 2 diabetes

2016 ◽  
Vol 6 (2) ◽  
pp. 20150075 ◽  
Author(s):  
Elin Nyman ◽  
Yvonne J. W. Rozendaal ◽  
Gabriel Helmlinger ◽  
Bengt Hamrén ◽  
Maria C. Kjellsson ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Large Scale ◽  
Whole Body ◽  
Current Status ◽  
Systems Pharmacology ◽  
Cellular Origin ◽  
Multi Level

We are currently in the middle of a major shift in biomedical research: unprecedented and rapidly growing amounts of data may be obtained today, from in vitro , in vivo and clinical studies, at molecular, physiological and clinical levels. To make use of these large-scale, multi-level datasets, corresponding multi-level mathematical models are needed, i.e. models that simultaneously capture multiple layers of the biological, physiological and disease-level organization (also referred to as quantitative systems pharmacology—QSP—models). However, today's multi-level models are not yet embedded in end-usage applications, neither in drug research and development nor in the clinic. Given the expectations and claims made historically, this seemingly slow adoption may seem surprising. Therefore, we herein consider a specific example—type 2 diabetes—and critically review the current status and identify key remaining steps for these models to become mainstream in the future. This overview reveals how, today, we may use models to ask scientific questions concerning, e.g., the cellular origin of insulin resistance, and how this translates to the whole-body level and short-term meal responses. However, before these multi-level models can become truly useful, they need to be linked with the capabilities of other important existing models, in order to make them ‘personalized’ (e.g. specific to certain patient phenotypes) and capable of describing long-term disease progression. To be useful in drug development, it is also critical that the developed models and their underlying data and assumptions are easily accessible. For clinical end-usage, in addition, model links to decision-support systems combined with the engagement of other disciplines are needed to create user-friendly and cost-efficient software packages.

scholarly journals A mixed-linkage (1,3;1,4)-β-D-glucan specific hydrolase mediates dark-triggered degradation of this plant cell wall polysaccharide

2021 ◽  
Author(s):  
Florian J Kraemer ◽  
China Lunde ◽  
Moritz Koch ◽  
Benjamin M Kuhn ◽  
Clemens Ruehl ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Large Scale ◽  
Plant Cell Wall ◽  
Causative Mutation ◽  
Grass Species ◽  
Calorie Intake ◽  
Cell Wall Polysaccharide ◽  
Transcript Accumulation

Abstract The presence of mixed-linkage (1,3;1,4)-β-D-glucan (MLG) in plant cell walls is a key feature of grass species such as cereals, the main source of calorie intake for humans and cattle. Accumulation of this polysaccharide involves the coordinated regulation of biosynthetic and metabolic machineries. While several components of the MLG biosynthesis machinery have been identified in diverse plant species, degradation of MLG is poorly understood. In this study, we performed a large-scale forward genetic screen for maize (Zea mays) mutants with altered cell wall polysaccharide structural properties. As a result, we identified a maize mutant with increased MLG content in several tissues, including adult leaves and senesced organs, where only trace amounts of MLG are usually detected. The causative mutation was found in the GRMZM2G137535 gene, encoding a GH17 licheninase as demonstrated by an in vitro activity assay of the heterologously expressed protein. In addition, maize plants overexpressing GRMZM2G137535 exhibit a 90% reduction in MLG content, indicating that the protein is not only required, but its expression is sufficient to degrade MLG. Accordingly, the mutant was named MLG hydrolase 1 (mlgh1). mlgh1 plants show increased saccharification yields upon enzymatic digestion. Stacking mlgh1 with lignin-deficient mutations results in synergistic increases in saccharification. Time profiling experiments indicate that wall MLG content is modulated during day/night cycles, inversely associated with MLGH1 transcript accumulation. This cycling is absent in the mlgh1 mutant, suggesting that the mechanism involved requires MLG degradation, which may in turn regulate MLGH1 gene expression.

scholarly journals Olive (Olea europaea L.) Genetic Transformation: Current Status and Future Prospects

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 386
Author(s):  
Elena Palomo-Ríos ◽  
Isabel Narváez ◽  
Fernando Pliego-Alfaro ◽  
José A. Mercado
Keyword(s):  
Genetic Transformation ◽  
Olea Europaea ◽  
Fungal Resistance ◽  
Current Status ◽  
Biotic And Abiotic Stress ◽  
Juvenile Period ◽  
Factors Affecting ◽  
Olea Europaea L ◽  
Olea Europaéa

Olive (Olea europaea L.) is the most characteristic and important oil crop of the Mediterranean region. Traditional olive cultivation is based on few tens cultivars of ancient origin. To improve this crop, novel selections with higher tolerance to biotic and abiotic stress, adaptable to high-density planting systems and resilient to climate change are needed; however, breeding programs are hindered by the long juvenile period of this species and few improved genotypes have been released so far. Genetic transformation could be of great value, in the near future, to develop new varieties or rootstocks in a shorter time; in addition, it has currently become an essential tool for functional genomic studies. The recalcitrance of olive tissues to their in vitro manipulation has been the main bottleneck in the development of genetic transformation procedures in this species; however, some important traits such as fungal resistance, flowering or lipid composition have successfully been manipulated through the genetic transformation of somatic embryos of juvenile or adult origin, providing a proof of the potential role that this technology could have in olive improvement. However, the optimization of these protocols for explants of adult origin is a prerequisite to obtain useful materials for the olive industry. In this review, initially, factors affecting plant regeneration via somatic embryogenesis are discussed. Subsequently, the different transformation approaches explored in olive are reviewed. Finally, transgenic experiments with genes of interest undertaken to manipulate selected traits are discussed.

Proteomics and genomics of microgravity

2006 ◽  
Vol 26 (3) ◽  
pp. 163-171 ◽  
Author(s):  
Heather L. Nichols ◽  
Ning Zhang ◽  
Xuejun Wen
Keyword(s):  
Large Scale ◽  
Current Status ◽  
Biological Processes ◽  
Physiological Changes ◽  
Research Activities ◽  
Genomics And Proteomics ◽  
Genomics Research ◽  
Underlying Mechanisms ◽  
Made In

Many serious adverse physiological changes occur during spaceflight. In the search for underlying mechanisms and possible new countermeasures, many experimental tools and methods have been developed to study microgravity caused physiological changes, ranging from in vitro bioreactor studies to spaceflight investigations. Recently, genomic and proteomic approaches have gained a lot of attention; after major scientific breakthroughs in the fields of genomics and proteomics, they are now widely accepted and used to understand biological processes. Understanding gene and/or protein expression is the key to unfolding the mechanisms behind microgravity-induced problems and, ultimately, finding effective countermeasures to spaceflight-induced alterations. Significant progress has been made in identifying the genes/proteins responsible for these changes. Although many of these genes and/or proteins were observed to be either upregulated or downregulated, however, no large-scale genomics and proteomics studies have been published so far. This review aims at summarizing the current status of microgravity-related genomics and proteomics studies and stimulating large-scale proteomics and genomics research activities.

Large-Scale In Vitro Hybridoma Culture: Current Status

1988 ◽  
Vol 6 (7) ◽  
pp. 784-786 ◽  
Author(s):  
A. Handa Corrigan
Keyword(s):  
Large Scale ◽  
Current Status ◽  
Hybridoma Culture

scholarly journals Small-Molecule Inhibitors of Chikungunya Virus: Mechanisms of Action and Antiviral Drug Resistance

2020 ◽  
Vol 64 (12) ◽  
Author(s):  
Kristina Kovacikova ◽  
Martijn J. van Hemert
Keyword(s):  
Drug Resistance ◽  
Small Molecule ◽  
Large Scale ◽  
Chikungunya Virus ◽  
Small Molecule Inhibitors ◽  
Antiviral Treatment ◽  
Antiviral Drug ◽  
Current Status ◽  
Antiviral Drug Resistance

ABSTRACT Chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus that has spread to more than 60 countries worldwide. CHIKV infection leads to a febrile illness known as chikungunya fever (CHIKF), which is characterized by long-lasting and debilitating joint and muscle pain. CHIKV can cause large-scale epidemics with high attack rates, which substantiates the need for development of effective therapeutics suitable for outbreak containment. In this review, we highlight the different strategies used for developing CHIKV small-molecule inhibitors, ranging from high-throughput cell-based screening to in silico screens and enzymatic assays with purified viral proteins. We further discuss the current status of the most promising molecules, including in vitro and in vivo findings. In particular, we focus on describing host and/or viral targets, mode of action, and mechanisms of antiviral drug resistance and associated mutations. Knowledge of the key molecular determinants of drug resistance will aid selection of the most promising antiviral agent(s) for clinical use. For these reasons, we also summarize the available information about drug-resistant phenotypes in Aedes mosquito vectors. From this review, it is evident that more of the active molecules need to be evaluated in preclinical and clinical models to address the current lack of antiviral treatment for CHIKF.

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