A simple and efficient strategy to produce transgene-free gene edited plants in one generation using paraquat resistant 1 as a selection marker

IntroductionDNA integration is a key factor limiting the marketing of CRISPR/Cas9-mediated gene edited crops. Several strategies have been established to obtain transgene-free gene edited plants; however, these strategies are usually time-consuming, technically difficult, providing low mutagenesis efficiency, and/or including a narrow host range.MethodTo overcome such issues, we established a paraquat resistant 1 (PAR1)-based positive screening (PARS) strategy, which achieved efficient screening of transgene-free gene edited plants.ResultsWith PARS, the screening efficiency of mutant increased by 2.81-fold on average, and approximately 10% of T1 plants selected via PARS were transgenefree. Moreover, heritable transgene-free mutations at target loci were identified in the T1 generation.DiscussionBased on the previous reports and our data, we know that paraquat is toxic to all green plants, PAR1 is conserved among all plant species tested, and the transient expression of Cas9 editor can produce transgene-free gene edited plants. Thus, we assume that the PARS strategy established here has the potential to be widely used to screen transgene-free mutants in various crops using diverse CRISPR/Cas9 delivery approaches

Conditional GANs with Auxiliary Discriminative Classifier

Conditional generative models aim to learn the underlying joint distribution of data and labels to achieve conditional data generation. Among them, the auxiliary classifier generative adversarial network (AC-GAN) has been widely used, but suffers from the problem of low intra-class diversity of the generated samples. The fundamental reason pointed out in this paper is that the classifier of AC-GAN is generator-agnostic, which therefore cannot provide informative guidance for the generator to approach the joint distribution, resulting in a minimization of the conditional entropy that decreases the intra-class diversity. Motivated by this understanding, we propose a novel conditional GAN with an auxiliary discriminative classifier (ADC-GAN) to resolve the above problem. Specifically, the proposed auxiliary discriminative classifier becomes generator-aware by recognizing the class-labels of the real data and the generated data discriminatively. Our theoretical analysis reveals that the generator can faithfully learn the joint distribution even without the original discriminator, making the proposed ADC-GAN robust to the value of the coefficient hyperparameter and the selection of the GAN loss, and stable during training. Extensive experimental results on synthetic and real-world datasets demonstrate the superiority of ADC-GAN in conditional generative modeling compared to state-of-the-art classifier-based and projection-based conditional GANs.Comment: ICML 202

Small RNA Sequencing Reveals Regulatory Roles of MicroRNAs in the Development of Meloidogyne incognita

MicroRNAs (miRNAs) are an extensive class of small regulatory RNAs. Knowing the specific expression and functions of miRNAs during root-knot nematode (RKN) (Meloidogyne incognita) development could provide fundamental information about RKN development as well as a means to design new strategies to control RKN infection, a major problem of many important crops. Employing high throughput deep sequencing, we identified a total of 45 conserved and novel miRNAs from two developmental stages of RKN, eggs and J2 juveniles, during their infection of cotton (Gossypium hirsutum L.). Twenty-one of the miRNAs were differentially expressed between the two stages. Compared with their expression in eggs, two miRNAs were upregulated (miR252 and miRN19), whereas 19 miRNAs were downregulated in J2 juveniles. Nine miRNAs were expressed at high levels, with >1000 reads per mapped million (RPM) sequenced reads in both eggs and J2 juveniles (miR1, miR124, miR2-3p, miR252, miR279, miR57-5p, miR7904, miR87, and miR92). Three miRNAs were only expressed in eggs (miR4738, miRN3, and miRN5). These differentially expressed miRNAs may control RKN development by regulating specific protein-coding genes in pathways associated with RKN growth and development

Exploring Structural Diversity of Microbe Secondary Metabolites Using OSMAC Strategy: A Literature Review

Microbial secondary metabolites (MSMs) have played and continue to play a highly significant role in the drug discovery and development process. Genetically, MSM chemical structures are biologically synthesized by microbial gene clusters. Recently, however, the speed of new bioactive MSM discovery has been slowing down due to consistent employment of conventional cultivation and isolation procedure. In order to alleviate this challenge, a number of new approaches have been developed. The strategy of one strain many compounds (OSMAC) has been shown as a simple and powerful tool that can activate many silent biogenetic gene clusters in microorganisms to make more natural products. This review highlights important and successful examples using OSMAC approaches, which covers changing medium composition and cultivation status, co-cultivation with other strain(s), adding enzyme inhibitor(s) and MSM biosynthetic precursor(s). Available evidences had shown that variation of cultivation condition is the most effective way to produce more MSMs and facilitate the discovery of new therapeutic agents

Role of glucose in the repair of cell membrane damage during squeeze distortion of erythrocytes in microfluidic capillaries

The rapid development of portable precision detection methods and the crisis of insufficient blood supply worldwide has led scientists to study mechanical visualization features beyond the biochemical properties of erythrocytes. Combined evaluation of currently known biochemical biomarkers and mechanical morphological biomarkers will become the mainstream of single-cell detection in the future. To explore the mechanical morphology of erythrocytes, a microfluidic capillary system was constructedin vitro, with flow velocity and glucose concentration as the main variables, and the morphology and ability of erythrocytes to recover from deformation as the main objects of analysis. We showed the mechanical distortion of erythrocytes under various experimental conditions. Our results showed that glucose plays important roles in improving the ability of erythrocytes to recover from deformation and in repairing the damage caused to the cell membrane during the repeated squeeze process. These protective effects were also confirmed inin vivoexperiments. Our results provide visual detection markers for single-cell chips and may be useful for future studies in cell aging

Uranium Bioreduction and Biomineralization

Following the development of nuclear science and technology, uranium contamination has been an ever increasing concern worldwide because of its potential for migration from the waste repositories and long-term contaminated environments. Physical and chemical techniques for uranium pollution are expensive and challenging. An alternative to these technologies is microbially mediated uranium bioremediation in contaminated water and soil environments due to its reduced cost and environmental friendliness. To date, four basic mechanisms of uranium bioremediation-uranium bioreduction, biosorption, biomineralization, and bioaccumulation-have been established, of which uranium bioreduction and biomineralization have been studied extensively. The objective of this review is to provide an understanding of recent developments in these two fields in relation to relevant microorganisms, mechanisms, influential factors, and obstacles

Alcohol, Volatile Fatty Acid, Phenol, and Methane Emissions from Dairy Cows and Fresh Manure

There are approximately 2.5 million dairy cows in California. Emission inventories list dairy cows and their manure as the major source of regional air pollutants, but data on their actual emissions remain sparse, particularly for smog-forming volatile organic compounds (VOCs) and greenhouse gases (GHGs). We report measurements of alcohols, volatile fatty acids, phenols, and methane (CH4) emitted from nonlactating (dry) and lactating dairy cows and their manure under controlled conditions. The experiment was conducted in an environmental chamber that simulates commercial concrete-floored freestall cow housing conditions. The fluxes of methanol, ethanol, and CH4 were measured from cows and/or their fresh manure. The average estimated methanol and ethanol emissions were 0.33 and 0.51 g cow−1 h−1 from dry cows and manure and 0.7 and 1.27 g cow−1 h−1 from lactating cows and manure, respectively. Both alcohols increased over time, coinciding with increasing accumulation of manure on the chamber floor. Volatile fatty acids and phenols were emitted at concentrations close to their detection limit. Average estimated CH4emissions were predominantly associated with enteric fermentation from cows rather than manure and were 12.35 and 18.23 g cow−1 h−1 for dry and lactating cows, respectively. Lactating cows produced considerably more gaseous VOCs and GHGs emissions than dry cows (P \u3c 0.001). Dairy cows and fresh manure have the potential to emit considerable amounts of alcohols and CH4 and research is needed to determine effective mitigation