scholarly journals The phosphite oxidoreductase gene, ptxD as a bio-contained chloroplast marker and crop-protection tool for algal biotechnology using Chlamydomonas

2019 ◽  
Vol 104 (2) ◽  
pp. 675-686 ◽  
Author(s):  
Saowalak Changko ◽  
Priscilla D. Rajakumar ◽  
Rosanna E. B. Young ◽  
Saul Purton
Keyword(s):  
Oral Delivery ◽  
Large Scale ◽  
Technical Problem ◽  
Crop Protection ◽  
Strain Improvement ◽  
Viral Pathogen ◽  
Algal Biotechnology ◽  
Bacterial Gene ◽  
Cell Factories ◽  
Phosphite Oxidoreductase

AbstractEdible microalgae have potential as low-cost cell factories for the production and oral delivery of recombinant proteins such as vaccines, anti-bacterials and gut-active enzymes that are beneficial to farmed animals including livestock, poultry and fish. However, a major economic and technical problem associated with large-scale cultivation of microalgae, even in closed photobioreactors, is invasion by contaminating microorganisms. Avoiding this requires costly media sterilisation, aseptic techniques during set-up and implementation of ‘crop-protection’ strategies during cultivation. Here, we report a strain improvement approach in which the chloroplast of Chlamydomonas reinhardtii is engineered to allow oxidation of phosphite to its bio-available form: phosphate. We have designed a synthetic version of the bacterial gene (ptxD)-encoding phosphite oxidoreductase such that it is highly expressed in the chloroplast but has a Trp→Opal codon reassignment for bio-containment of the transgene. Under mixotrophic conditions, the growth rate of the engineered alga is unaffected when phosphate is replaced with phosphite in the medium. Furthermore, under non-sterile conditions, growth of contaminating microorganisms is severely impeded in phosphite medium. This, therefore, offers the possibility of producing algal biomass under non-sterile conditions. The ptxD gene can also serve as a dominant marker for genetic engineering of any C. reinhardtii strain, thereby avoiding the use of antibiotic resistance genes as markers and allowing the ‘retro-fitting’ of existing engineered strains. As a proof of concept, we demonstrate the application of our ptxD technology to a strain expressing a subunit vaccine targeting a major viral pathogen of farmed fish.

scholarly journals RNAi Crop Protection Advances

2021 ◽  
Vol 22 (22) ◽  
pp. 12148
Author(s):  
Alejandro Hernández-Soto ◽  
Randall Chacón-Cerdas
Keyword(s):  
Gene Silencing ◽  
Oral Delivery ◽  
Large Scale ◽  
Crop Protection ◽  
Scale Production ◽  
Recombinant Production ◽  
Rnai Technology ◽  
Large Scale Production ◽  
Induction Of Resistance ◽  
Multiple Chemical

RNAi technology is a versatile, effective, safe, and eco-friendly alternative for crop protection. There is plenty of evidence of its use through host-induced gene silencing (HIGS) and emerging evidence that spray-induced gene silencing (SIGS) techniques can work as well to control viruses, bacteria, fungi, insects, and nematodes. For SIGS, its most significant challenge is achieving stability and avoiding premature degradation of RNAi in the environment or during its absorption by the target organism. One alternative is encapsulation in liposomes, virus-like particles, polyplex nanoparticles, and bioclay, which can be obtained through the recombinant production of RNAi in vectors, transgenesis, and micro/nanoencapsulation. The materials must be safe, biodegradable, and stable in multiple chemical environments, favoring the controlled release of RNAi. Most of the current research on encapsulated RNAi focuses primarily on oral delivery to control insects by silencing essential genes. The regulation of RNAi technology focuses on risk assessment using different approaches; however, this technology has positive economic, environmental, and human health implications for its use in agriculture. The emergence of alternatives combining RNAi gene silencing with the induction of resistance in crops by elicitation and metabolic control is expected, as well as multiple silencing and biotechnological optimization of its large-scale production.

scholarly journals RNAi Crop Protection Advances

2021 ◽  
Author(s):  
Alejandro Hernández-Soto ◽  
Randall Chacón-Cerdas
Keyword(s):  
Gene Silencing ◽  
Oral Delivery ◽  
Large Scale ◽  
Crop Protection ◽  
Scale Production ◽  
Recombinant Production ◽  
Rnai Technology ◽  
Large Scale Production ◽  
Induction Of Resistance ◽  
Multiple Chemical

RNAi technology is a versatile, effective, safe, and eco-friendly alternative for crop protection. There is plenty of evidence of its use through Host-induced gene silencing (HIGS) and spray-induced gene silencing (SIGS) techniques to control viruses, bacteria, fungi, insects, and nematodes. As for SIGS, its most significant challenge is achieving stability and avoiding premature degradation of RNAi in the environment or during its absorption in the target organism. One alternative is the encapsulation in liposomes, virus-like particles, polyplex nanoparticles, and bio-clay, which can be obtained through the recombinant production of RNAi in vectors, transgenesis, and micro/nanoencapsulation. The materials must be safe, biodegradable, and stable in multiple chemical environments favoring the controlled release of RNAi. Most of the current research of encapsulated RNAi focuses primarily on oral delivery to control insects by silencing essential genes. The regulation of RNAi technology focuses on risk assessment from different approaches; however, this technology has positive characteristics for its use in agriculture from the economic, environmental, and human health implications. The emergence of alternatives combining RNAi gene silencing with the induction of resistance in crops by elicitation and metabolic control is expected, as well as multiple silencing and biotechnological optimization of its large-scale production.

scholarly journals Harnessing the yeast Saccharomyces cerevisiae for the production of fungal secondary metabolites

2021 ◽  
Author(s):  
Guokun Wang ◽  
Douglas B. Kell ◽  
Irina Borodina
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Secondary Metabolites ◽  
High Throughput Screening ◽  
Large Scale ◽  
Strain Improvement ◽  
Cell Factory ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cell Factories ◽  
Genetically Engineer ◽  
Fungal Secondary Metabolites

Abstract Fungal secondary metabolites (FSMs) represent a remarkable array of bioactive compounds, with potential applications as pharmaceuticals, nutraceuticals, and agrochemicals. However, these molecules are typically produced only in limited amounts by their native hosts. The native organisms may also be difficult to cultivate and genetically engineer, and some can produce undesirable toxic side-products. Alternatively, recombinant production of fungal bioactives can be engineered into industrial cell factories, such as aspergilli or yeasts, which are well amenable for large-scale manufacturing in submerged fermentations. In this review, we summarize the development of baker’s yeast Saccharomyces cerevisiae to produce compounds derived from filamentous fungi and mushrooms. These compounds mainly include polyketides, terpenoids, and amino acid derivatives. We also describe how native biosynthetic pathways can be combined or expanded to produce novel derivatives and new-to-nature compounds. We describe some new approaches for cell factory engineering, such as genome-scale engineering, biosensor-based high-throughput screening, and machine learning, and how these tools have been applied for S. cerevisiae strain improvement. Finally, we prospect the challenges and solutions in further development of yeast cell factories to more efficiently produce FSMs.

scholarly journals RNAi Crop Protection Advances

2021 ◽  
Author(s):  
Alejandro Hernández-Soto ◽  
Randall Chacón-Cerdas
Keyword(s):  
Gene Silencing ◽  
Oral Delivery ◽  
Large Scale ◽  
Crop Protection ◽  
Scale Production ◽  
Recombinant Production ◽  
Rnai Technology ◽  
Large Scale Production ◽  
Induction Of Resistance ◽  
Multiple Chemical

RNAi technology is a versatile, effective, safe, and eco-friendly alternative for crop protection. There is plenty of evidence of its use through Host-induced gene silencing (HIGS) and spray-induced gene silencing (SIGS) techniques to control viruses, bacteria, fungi, insects, and nematodes. As for SIGS, its most significant challenge is achieving stability and avoiding premature degradation of RNAi in the environment or during its absorption in the target organism. One alternative is the encapsulation in liposomes, virus-like particles, polyplex nanoparticles, and bio-clay, which can be obtained through the recombinant production of RNAi in vectors, transgenesis, and micro/nanoencapsulation. The materials must be safe, biodegradable, and stable in multiple chemical environments favoring the controlled release of RNAi. Most of the current research of encapsulated RNAi focuses primarily on oral delivery to control insects by silencing essential genes. The regulation of RNAi technology focuses on risk assessment from different approaches; however, this technology has positive characteristics for its use in agriculture from the economic, environmental, and human health implications. The emergence of alternatives combining RNAi gene silencing with the induction of resistance in crops by elicitation and metabolic control is expected, as well as multiple silencing and biotechnological optimization of its large-scale production.

scholarly journals RNAi Crop Protection Advances

2021 ◽  
Author(s):  
Alejandro Hernández-Soto ◽  
Randall Chacón-Cerdas
Keyword(s):  
Gene Silencing ◽  
Oral Delivery ◽  
Large Scale ◽  
Crop Protection ◽  
Scale Production ◽  
Recombinant Production ◽  
Rnai Technology ◽  
Large Scale Production ◽  
Induction Of Resistance ◽  
Multiple Chemical

RNAi technology is a versatile, effective, safe, and eco-friendly alternative for crop protection. There is plenty of evidence of its use through host-induced gene silencing (HIGS) and spray-induced gene silencing (SIGS) techniques to control viruses, bacteria, fungi, insects, and nematodes. For SIGS, its most significant challenge is achieving stability and avoiding premature degradation of RNAi in the environment or during its absorption by the target organism. One alternative is encapsulation in liposomes, virus-like particles, polyplex nanoparticles, and bioclay, which can be obtained through the recombinant production of RNAi in vectors, transgenesis, and micro/nanoencapsulation. The materials must be safe, biodegradable, and stable in multiple chemical environments, favoring the controlled release of RNAi. Most of the current research on encapsulated RNAi focuses primarily on oral delivery to control insects by silencing essential genes. The regulation of RNAi technology focuses on risk assessment using different approaches; however, this technology has positive economic, environmental, and human health implications for its use in agriculture. The emergence of alternatives combining RNAi gene silencing with the induction of resistance in crops by elicitation and metabolic control is expected, as well as multiple silencing and biotechnological optimization of its large-scale production.

scholarly journals Fabrication of Ag micro-particles based on stress-induced migration by using multilayered structure with artificial holes array

2021 ◽  
Vol 104 (3) ◽  
pp. 003685042110381
Author(s):  
Yebo Lu ◽  
Quan Sun ◽  
Chuncheng Zuo ◽  
Chengli Tang ◽  
Haijun Song ◽  
...  
Keyword(s):  
Mass Production ◽  
Large Scale ◽  
Heating Temperature ◽  
Technical Problem ◽  
Industrial Applications ◽  
Passivation Layer ◽  
Micro Particles ◽  
Ag Particles ◽  
Controllable Fabrication ◽  
Foil Substrate

Silver micro/nanomaterials have attracted a great deal of attention due to their superior physicochemical properties. The atomic migration driven by electromigration or stress-induced migration has been demonstrated to be a promising method for the fabrication of metallic micro-/nanomaterials because of the advantage of simple processing. However, how to realize the controllable fabrication and mass production is still the critical technical problem for the method to be used in large-scale industrial applications. In this paper, the multilayered samples consisted of copper foil substrate, Ti adhesive layer, Ag film, and TiN passivation layer and with arrays of artificial holes on the passivation layer were applied to prepare arrays of Ag micro-particles. For the purpose of controllable fabrication, stress-induced migration experiments combined with finite element simulation were applied to analyze the influence of the passivation layer thickness and the heating temperature on the atom migration and Ag particles growing behavior. And the relationship between size of the fabricated Ag particles and the processing parameters of stress-induced migration experiments were also investigated. As a result, a proper structure size of the multilayered samples and heating temperature were recommended, which can be used for the Ag micro-particles controllable fabrication and mass production.

scholarly journals Small RNA profiling in Mycobacterium tuberculosis identifies MrsI as necessary for an anticipatory iron sparing response

2018 ◽  
Vol 115 (25) ◽  
pp. 6464-6469 ◽  
Author(s):  
Elias R. Gerrick ◽  
Thibault Barbier ◽  
Michael R. Chase ◽  
Raylin Xu ◽  
Josie François ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Large Scale ◽  
Direct Interaction ◽  
Human Macrophage ◽  
Binding Interaction ◽  
Bacterial Gene ◽  
Rna Profiling ◽  
Iron Deprivation ◽  
Bacterial Gene Expression ◽  
Small Regulatory Rnas

One key to the success of Mycobacterium tuberculosis as a pathogen is its ability to reside in the hostile environment of the human macrophage. Bacteria adapt to stress through a variety of mechanisms, including the use of small regulatory RNAs (sRNAs), which posttranscriptionally regulate bacterial gene expression. However, very little is currently known about mycobacterial sRNA-mediated riboregulation. To date, mycobacterial sRNA discovery has been performed primarily in log-phase growth, and no direct interaction between any mycobacterial sRNA and its targets has been validated. Here, we performed large-scale sRNA discovery and expression profiling in M. tuberculosis during exposure to five pathogenically relevant stresses. From these data, we identified a subset of sRNAs that are highly induced in multiple stress conditions. We focused on one of these sRNAs, ncRv11846, here renamed mycobacterial regulatory sRNA in iron (MrsI). We characterized the regulon of MrsI and showed in mycobacteria that it regulates one of its targets, bfrA, through a direct binding interaction. MrsI mediates an iron-sparing response that is required for optimal survival of M. tuberculosis under iron-limiting conditions. However, MrsI is induced by multiple host-like stressors, which appear to trigger MrsI as part of an anticipatory response to impending iron deprivation in the macrophage environment.

Harnessing chemical ecology for environment-friendly crop protection

2021 ◽  
Author(s):  
Seogchan Kang ◽  
Rhea Lumactud ◽  
Ningxiao Li ◽  
Terrence H Bell ◽  
HyeSeon Kim ◽  
...  
Keyword(s):  
Disease Control ◽  
Large Scale ◽  
Crop Protection ◽  
Bioactive Metabolites ◽  
Small Scale ◽  
Environment Friendly ◽  
Protection Strategies ◽  
Health Related ◽  
Microbe Interactions ◽  
Synthetic Pesticides

Heavy reliance on synthetic pesticides for crop protection becomes increasingly unsustainable, calling for robust alternative strategies that do not degrade the environment and vital ecosystem services. There exist numerous reports of successful disease control using various microbes in small-scale trials. However, their inconsistent efficacy has hampered large-scale applications. An enhanced understanding of how beneficial microbes interact with plants, other microbes, and the environment and which factors affect their efficacy of disease control is crucial to deploy microbial allies as effective and reliable pesticide alternatives. Diverse metabolites produced by plants and microbes participate in pathogenesis and defense, regulate the growth and development of themselves and neighboring organisms, help maintain cellular homeostasis under varied environmental conditions, and affect the assembly and activity of plant and soil microbiomes. However, research on the metabolites associated with plant growth/health-related processes, except antibiotics, has not received adequate attention. This review highlights several classes of metabolites known or suspected to affect plant health, focusing on those associated with biocontrol and belowground plant-microbe and microbe-microbe interactions. The review also presents how new insights anticipated from systematically exploring the diversity and mechanism of action of bioactive metabolites can be harnessed to develop novel crop protection strategies.

scholarly journals Restructured Lactococcus lactis strains with emergent properties constructed by a novel highly efficient screening system

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Fulu Liu ◽  
Yating Zhang ◽  
Wanjin Qiao ◽  
Duolong Zhu ◽  
Haijin Xu ◽  
...  
Keyword(s):  
Lactococcus Lactis ◽  
Large Scale ◽  
Gene Deletion ◽  
Selectable Marker ◽  
Genome Reduction ◽  
Emergent Properties ◽  
Metabolic Capacity ◽  
Efficient System ◽  
Cell Factories ◽  
Efficient Screening

Abstract Background After 2.83% genome reduction in Lactococcus lactis NZ9000, a good candidate host for proteins production was obtained in our previous work. However, the gene deletion process was time consuming and laborious. Here, we proposed a convenient gene deletion method suitable for large-scale genome reduction in L. lactis NZ9000. Results Plasmid pNZ5417 containing a visually selectable marker PnisZ-lacZ was constructed, which allowed more efficient and convenient screening of gene deletion mutants. Using this plasmid, two large nonessential DNA regions, L-4A and L-5A, accounting for 1.25% of the chromosome were deleted stepwise in L. lactis 9k-3. When compared with the parent strain, the mutant L. lactis 9k-5A showed better growth characteristics, transformability, carbon metabolic capacity, and amino acids biosynthesis. Conclusions Thus, this study provides a convenient and efficient system for large-scale genome deletion in L. lactis through application of visually selectable marker, which could be helpful for rapid genome streamlining and generation of restructured L. lactis strains that can be used as cell factories.

scholarly journals Molecular identification of the swede midge (Diptera: Cecidomyiidae)

2004 ◽  
Vol 136 (6) ◽  
pp. 771-780 ◽  
Author(s):  
Juerg E. Frey ◽  
Beatrice Frey ◽  
Robert Baur
Keyword(s):  
Large Scale ◽  
Crop Protection ◽  
Adult Life ◽  
Molecular Diagnostic ◽  
Pest Species ◽  
Adult Life Span ◽  
Protection Measures ◽  
Major Pest ◽  
Swede Midge ◽  
Species Specific

AbstractEarly detection of pest infestation is a prerequisite for sustainable crop protection. However, many pest species are difficult to detect and thus infestation is diagnosed from damage observed on the respective crop. This diagnosis is often made too late for implementation of crop protection measures, and serious crop losses may result. The swede midge, Contarinia nasturtii Kieffer, is a major pest of Brassica L. (Brassicaceae) vegetables in Europe that has recently invaded North America. With its small size and short adult life-span, and the cryptic lifestyle of the larvae feeding at the growing points of its host plants, it is usually detected only after damage has already occurred. Furthermore, because field-trapped specimens are rarely fully intact, it is extremely difficult to identify. Therefore, we developed a species-specific molecular diagnostic method that enables reliable identification of swede midge from various sources such as alcohol or sticky glue traps. The method enables large-scale screening of field-trapped specimens and is used to evaluate the attractiveness and specificity of pheromone traps that are currently under development.

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