Mechanism Of Sterility Research Articles

Biological Activity and Sterilization Mechanism of Marine Fungi-derived Aromatic Butenolide Asperbutenolide A Against Staphylococcus aureus.

Marine fungi represent a huge untapped resource of natural products. The bio-activity of a new asperbutenolide A from marine fungus Aspergillus terreus was not well known. In the present study, the minimum inhibitory concentration (MIC) and RNA-Sequencing were used to analyze the bio-activity and sterilization mechanism of asperbutenolide A against clinical pathogenic microbes. The results showed that the MICs of asperbutenolide A against methicillin-resistant Staphylococcus aureus (MRSA) were 4.0-8.0 μg/mL. The asperbutenolide A present poor bio-activity against with candida. The sterilization mechanism of asperbutenolide A against MRSA showed that there were 1426 differentially-expressed genes (DEGs) between the groups of MRSA treated with asperbutenolide A and negative control. Gene Ontology (GO) classification analysis indicated that the DEGs were mainly involved in cellular process, metabolic process, cellular anatomical entity, binding, catalytic activity, etc. Kyoto Encyclopedia of Genes and Genomes (KEGG) classification analysis showed that these DEGs were mainly enriched in amino acid metabolism, carbohydrate metabolism, membrane transport, etc. Moreover, qRT-PCR showed similar trends in the expressions of argF, ureA, glmS and opuCA with the RNA-Sequencing. These results indicated that asperbutenolide A was with ideal bio-activity against with MRSA and could be as a new antibacterial agent.

Construction of sandwich-structured V2CTx@PDA@Ag nanosheet composite for enhanced near-infrared photothermocatalytic sterilization performance

The long-term use of antibiotics leads to drug resistance, it is insufficient to combat stubborn pathogens. Therefore, it urgently needs a material that can quickly and effectively eradicate bacteria, especially for resistant bacteria and their biofilm structures that are difficult to eliminate with conventional antibiotics. This article adopts a new 2D layered V2CTx MXene material, which utilizes in-situ coating method to stimulate dopamine self polymerization and fix nano silver onto V2CTx nanosheets. V2CTx@PDA@Ag showed very significant antibacterial effect under 808 nm laser illumination for 30 min. After analyzing the sterilization mechanism, the photothermal synergistic sterilization of composite mainly relies on physical contact, the generation of reactive oxygen species, and the photothermal synergistic effect. It is worth mentioning that after V2CTx is coated with PDA, the photothermal efficiency is improved, V2CTx and nano silver are also effectively connected. It proved that the composite has stable and efficient antibacterial properties.

Comparative transcriptome analysis reveals the molecular mechanism of sterility induced by irradiation of Plutella xylostella (Linnaeus)

Plutella xylostella (Linnaeus) is an important pest of cruciferous plants, which is harmful all over the world, causing serious economic losses, and its drug resistance is increasing rapidly. The sterile insect technique (SIT) is a green control method and does not cause resistance. In this study, transcriptomics and bioinformatics were used to explore the effects of irradiation on the reproductive function of Plutella xylostella, and the response mechanism of sterility under irradiation was initially revealed. We identified 3342 (1682 up-regulated, 1660 down-regulated), 1963 (1042 up-regulated, 921 down-regulated) and 1531 (721 up-regulated, 810 down-regulated) differentially expressed genes (DEGs) in the 200 Gy vs CK (Control Check), 400 Gy vs CK and 400 Gy vs 200 Gy groups, respectively. GO and KEGG analyses were performed for DEGs in each group. The results showed that 200 Gy activated the downstream phosphorylation pathway and inhibited the cytochrome p450 immune response mechanism. 400 Gy promoted protein decomposition and absorption pathways, autophagy pathways, etc. Down-regulated genes were concentrated in the transformation process of energy metabolizing substances such as ATP, phosphorylation signaling pathway, and insulin, while up-regulated genes were concentrated in biological regulation and metabolic processes. Eight genes in the phosphorylation pathway were selected for qRT-PCR verification, and the results showed that the phosphorylation of different dose groups was regulated in different ways. 400 Gy used positive feedback regulation, while the phosphorylation of F1 used negative feedback regulation.

Analysis of the Candidate Genes and Underlying Molecular Mechanism of P198, an RNAi-Related Dwarf and Sterile Line.

The genome-wide long hairpin RNA interference (lhRNAi) library is an important resource for plant gene function research. Molecularly characterizing lhRNAi mutant lines is crucial for identifying candidate genes associated with corresponding phenotypes. In this study, a dwarf and sterile line named P198 was screened from the Brassica napus (B. napus) RNAi library. Three different methods confirmed that eight copies of T-DNA are present in the P198 genome. However, only four insertion positions were identified in three chromosomes using fusion primer and nested integrated polymerase chain reaction. Therefore, the T-DNA insertion sites and copy number were further investigated using Oxford Nanopore Technologies (ONT) sequencing, and it was found that at least seven copies of T-DNA were inserted into three insertion sites. Based on the obtained T-DNA insertion sites and hairpin RNA (hpRNA) cassette sequences, three candidate genes related to the P198 phenotype were identified. Furthermore, the potential differentially expressed genes and pathways involved in the dwarfism and sterility phenotype of P198 were investigated by RNA-seq. These results demonstrate the advantage of applying ONT sequencing to investigate the molecular characteristics of transgenic lines and expand our understanding of the complex molecular mechanism of dwarfism and male sterility in B. napus.

Investigating the molecular mechanism of sterility in female triploid Pacific oyster (Crassostrea gigas)

The emergence of triploid oysters has freed the oyster market from the problem of interruptions in the breeding season, allowing for year-round availability. However, according to recent statistics, the phenomenon of fertility in triploid oysters has been increasing yearly, perhaps eventually leading to the loss of the sterility characteristic. This has in turn affected the oyster farming industry. Therefore, we attempted to mine key genes through transcriptomics to find the causes of triploid fertility. During our surveys and sampling, we found that most of the fertile triploid Crassostrea gigas were females, with a much smaller percentage of males. Therefore, the main objective of this study was to analyze the differences between fertile and sterile triploid female C. gigas. We performed transcriptome analysis of fertile female triploid C. gigas and sterile female triploid C. gigas and identified 2361 up-regulated differentially expressed genes (DEGs) and 1541 down-regulated DEGs, respectively. Enrichment analysis of these DEGs revealed that most GO terms and KEGG pathways were associated with mitosis. We then created a protein–protein interaction (PPI) network using genes enriched in mitosis-associated KEGG pathways. Finally, we screened and validated 26 key genes by quantitative RT-PCR and all were found to be downregulated in expression in sterile female triploids. The main cause of sterility is the suppression of the expression of genes that control the process of germ cell proliferation, the failure of the mitotic cycle to proceed smoothly, and the inability to produce an oogonium. These results can be used to explore ways to reduce the fertility of triploid C. gigas and to promote the breeding of higher quality triploid oysters.

A P-type pentatricopeptide repeat protein ZmRF5 promotes 5' region partial cleavages of atp6c transcripts to restore the fertility of CMS-C maize by recruiting a splicing factor.

A fast evolution within mitochondria genome(s) often generates discords between nuclear and mitochondria, which is manifested as cytoplasmic male sterility (CMS) and fertility restoration (Rf) system. The maize CMS-C trait is regulated by the chimeric mitochondrial gene, atp6c, and can be recovered by the restorer gene ZmRf5. Through positional cloning in this study, we identified the nuclear restorer gene, ZmRf5, which encodes a P-type pentatricopeptide repeat (PPR) family protein. The over-expression of ZmRf5 brought back the fertility to CMS-C plants, whereas its genomic editing by CRISPR/Cas9 induced abortive pollens in the restorer line. ZmRF5 is sorted to mitochondria, and recruited RS31A, a splicing factor, through MORF8 to form a cleaving/restoring complex, which promoted the cleaving of the CMS-associated transcripts atp6c by shifting the major cleavage site from 480th nt to 344 th nt for fast degradation, and preserved just right amount of atp6c RNA for protein translation, providing adequate ATP6C to assembly complex V, thus restoring male fertility. Interestingly, ATP6C in the sterile line CMo17A, with similar cytology and physiology changes to YU87-1A, was accumulated much less than it in NMo17B, exhibiting a contrary trend in the YU87-1 nuclear genome previously reported, and was restored to normal level in the presence of ZmRF5. Collectively these findings unveil a new molecular mechanism underlying fertility restoration by which ZmRF5 cooperates with MORF8 and RS31A to restore CMS-C fertility in maize, complemented and perfected the sterility mechanism, and enrich the perspectives on communications between nucleus and mitochondria.

Photothermocatalytic sterilization activity enhancement and mechanism evaluation of WO3/TpPa-1/N-Nb2CTx constructed with a 2D Z-type heterojunction WO3/TpPa-1 and 2D co-catalyst Nb2CTx

Foodborne pathogens are the main factors causing food poisoning, and it is of great significance to develop novel nanocomposites to obtain efficient and stable photothermal-assisted photocatalysts for killing foodborne pathogens. In this paper, Z-type heterojunction WO3/TpPa-1 with a core-shell structure was constructed by in-situ synthesis, and the Nb2CTx was used as a co-catalyst to obtain an efficient ternary composite WO3/TpPa-1/N-Nb2CTx. Compared to the monomers, the ternary composites improved light trapping, interfacial separation effectiveness, and the mobility of photogenerated carriers. The WO3/TpPa-1/15% N-Nb2CTx has the best sterilization efficiency of 99.69% under visible-infrared light irradiation for 30 min. The construction of WO3/TpPa-1/N-Nb2CTx promoted the separation of electron and hole pairs, which improved the electron transport efficiency and the generation of reactive oxygen species. In addition, the excellent photothermal effect of Nb2CTx improves the sterilization performance of WO3/TpPa-1/N-Nb2CTx. The WO3/TpPa-1/N-Nb2CTx has a broad application prospect in photothermal-assisted photocatalytic sterilization.

Different mechanisms of X-ray irradiation-induced male and female sterility in Aedes aegypti

BackgroundAedes aegypti (Ae. aegypti) is the major vector that transmits many diseases including dengue, Zika, and filariasis in tropical and subtropical regions. Due to the growing resistance to chemical-based insecticides, biological control methods have become an emerging direction to control mosquito populations. The sterile insect technique (SIT) deploys high doses of ionizing radiation to sterilize male mosquitoes before the release. The Wolbachia-based population suppression method of the incompatible insect technique (IIT) involves the release of Wolbachia-infected males to sterilize uninfected field females. Due to the lack of perfect sex separation tools, a low percentage of female contamination is detected in the male population. To prevent the unintentional release of these Wolbachia-infected females which might result in population replacement, a low dose of X-ray irradiation is deployed to sterilize any female escapees. However, it remains unclear whether these irradiation-induced male and female sterilizations share common mechanisms.ResultsIn this work, we set out to define the minimum dose of X-ray radiation required for complete female sterilization in Ae. aegypti (NEA-EHI strain). Further results showed that this minimum dose of X-ray irradiation for female sterilization significantly reduced male fertility. Similar results have been reported previously in several operational trials. By addressing the underlying causes of the sterility, our results showed that male sterility is likely due to chromosomal damage in the germ cells induced by irradiation. In contrast, female sterility appears to differ and is likely initiated by the elimination of the somatic supporting cells, which results in the blockage of the ovariole maturation. Building upon these findings, we identified the minimum dose of X-ray irradiation on the Wolbachia-infected NEA-EHI (wAlbB-SG) strain, which is currently being used in the IIT-SIT field trial. Compared to the uninfected parental strain, a lower irradiation dose could fully sterilize wAlbB-SG females. This suggests that Wolbachia-carrying mosquitoes are more sensitive to irradiation, consistent with a previous report showing that a lower irradiation dose fully sterilized Wolbachia-infected Ae. aegypti females (Brazil and Mexican strains) compared to those uninfected controls.ConclusionsOur findings thus reveal the distinct mechanisms of ionizing X-ray irradiation-induced male or female sterility in Ae. aegypti mosquitoes, which may help the design of X-ray irradiation-based vector control methods.

Production of sterile mono-sex triploid yellow drum (Nibea albiflora): genotypic females and sex-reversed phenotypic males with emphasis on utilization as surrogate broodstock.

Production of sterile mono-sex fish is of great significance for sustainable aquaculture as well as germ cell transplantation. In this study, we aimed to produce mono-sex triploid yellow drum, including genotypic females (XXX female) and sex-reversed phenotypic males (XXX male). Firstly, the mono-female triploids were produced through cold-shock treatment on eggs fertilized with sperm from neo-males. Then, the mono-male triploids were produced by the sex reversal of mono-female triploids with oral administration of letrozole (LZ). We comparatively investigated the growth and gonadal development in the mono-sex triploids. The results showed that the triploids displayed similar growth performance to their diploids throughout their first year, but had impaired gonadosomatic index and gametogenesis. No mature gametes were produced in the triploids during their first spawning season. Meanwhile, we analyzed the process of gametogenesis in the both sex of triploids. Ultrastructure of gametogenesis showed that the germ cells arrested at abnormal metaphase 1 in females, while males had irregular meiotic divisions, variable-sized spermatid and degenerated cells. The expression levels of meiosis-related genes (i.e., sycp3 and rec8) confirmed the abnormal meiosis in the triploids. Furthermore, the gonadal development was also determined by the expression patterns of vasa, dmrt1 and cyp19a1a. Abnormal expression of vasa mRNA and protein were detected in triploids. High cyp19a1a expression levels suggested the sex steroid hormones production might be at least partially functional in triploid females. In addition, high dmrt1 expression levels confirmed the masculinization and testicular development of sex-reversed triploid males by LZ. Our findings provide an efficient protocol to produce sterile mono-sex triploid yellow drum and provide new insights into the mechanism of gonadal sterility of triploid fish.

An iTRAQ-based quantitative proteomic analysis reveals the role of mitochondrial complex I subunits in S-type cytoplasmic male sterility of maize

Maize S-type cytoplasmic male sterility (CMS-S) arises from the activity of the mitochondrial gene orf355. This sterility can be counteracted by the nuclear fertility-restoring allele, Rf3. CMS-S occurs when bicellular pollen collapses following microspore mitosis. Despite this knowledge, the precise protein alterations in CMS-S mitochondria preceding pollen collapse are not well-understood. Our study compared the mitochondrial proteomic profiles between CMS-S and maintainer lines. We found that oxidative phosphorylation (OXPHOS) and glycolysis were significantly associated with CMS-S. A detailed analysis of the differentially abundant proteins (DAPs) associated with the OXPHOS pathway revealed that complex I (CI) subunits play a vital role in the degenerative process of maize CMS-S. Among these, the CI-B8 subunit exhibited abundant presence in CMS-S and displayed earlier transcriptional changes compared to other DAP genes. A yeast two-hybrid assay revealed a physical interaction between another DAP, the CI-13kDa subunit, and orf355 in yeast. These findings highlight the pivotal role played by complex I in the sterility mechanism of CMS-S in maize microspores.

Structure optimization of pulsed electric field processor and its sterilization effect

Abstract Pulsed electric field (PEF) technology is a highly promising non-thermal processing technique, which holds great potential for sterilizing liquid food. The effectiveness of this treatment depends on two crucial factors: pulse parameters and the structure of the processor. In this study, we focus on optimizing the shape of insulators within the PEF processor to improve the sterilization effect. This research provides a reliable technical reference for designing industrial equipment. The numerical simulation of multi-physics fields was employed to analyze the temperature, electric field, and fluid field distributions for different insulators. Ultimately, the geometric structure of the insulator was optimized by embedding a 0.7-mm arc. Sterilization experiments were then conducted on Escherichia coli and Staphylococcus aureus suspensions with conductivities similar to those of real grapefruit juice. The sterilization effect of the processor with the optimized structure and the maximum applied voltage was examined at the same driving frequency. The results indicate that compared to the original structure, there is an increase in withstanding voltage by 5–10 kV while maintaining significantly improved bactericidal effects at the same applied voltage. Furthermore, we preliminarily discussed the sterilization mechanism by combining electroporation theory with the electroporation threshold of S. aureus.

Nano zero-valent iron-based fiber electrode for efficient electro-Fenton treatment of pharmaceutical wastewater: Mechanism of degradation and sterilization

In this study, a novel metal–organic framework (MOF) derived fiber electrode (NZVIF-800) was successfully fabricated by a novel electrostatic spinning and pyrolysis procedure. The NZVIF-800 electrode exhibited great catalytic activity in a heterogeneous electro-Fenton (EF) system for organic degradation, in which the secnidazole (SCZ) was completely degraded within 60 min with excellent stability (no significant change after eight cycles). Importantly, the NZVIF-800 electrode was also highly effective for decontaminating actual pharmaceutical wastewater, in which the TOC and COD removal reached 38% and 47%, respectively, after 4 h EF reaction. Based on experimental analysis, microstructure characterization, and theoretical calculations, the detailed reaction mechanism of the NZVIF-800 electrode was revealed. The impressive EF performance was mainly attributed to the in situ generation of active nano-zero-valent iron (NZVI) derived from the MOF pyrolysis and the confinement effect of the encased carbon layer that could effectively inhibit the loss and inactivation of Fe active sites. The degradation pathways of organic pollutants in simulated and real wastewater were proposed in detail. Significantly, the EF system with NZVIF-800 electrode exhibited strong sterilization ability for the wastewater matrix as evidenced by the colony condition, OD600 values, and Illumina MiSeq sequencing platform analysis (up to 95% sterilization efficiency within 4 h), expanding its application scope for actual wastewater treatment.

Potential use of plasma‐activated water on Escherichia coli for sterilization: Efficacy and mechanism

AbstractThe plasma‐activated water (PAW) produced by low‐temperature plasma (LTP) was applied to this research because of its safety and no thermal damage. Therefore, the physicochemical properties of PAW, as well as the efficacy and sterilization mechanism of Escherichia coli, were discussed. The PAW (pH 1.27, conductivity 6400 μS/cm) could reduce E. coli by 1.31‐log reduction using LTP at 70 W for 9 min. The results demonstrated that PAW caused DNA and protein leakage with malondialdehyde production. This study may provide a basis for the theoretical research of PAW sterilization. As an effective sterilant, PAW would be a promising alternative strategy for cleaning of E. coli from pipes and filters in food factories.

Elucidation of composition of chlorine compounds in acidic sodium chlorite solution using ion chromatography.

With the spread of coronavirus infections, the demand for disinfectants, such as a sodium chlorite solution, has increased worldwide. Sodium chlorite solution is a food additive and is used in a wide range of applications. There is evidence that chlorous acid or sodium chlorite is effective against various bacteria, but the actual mechanism is not well understood. One reason for this is that the composition of chlorine-based compounds contained in sodium chlorite solutions has not been clearly elucidated. The composition can vary greatly with pH. In addition, the conventional iodometric titration method, the N,N-diethyl-p-phenylenediamine sulfate (DPD) method and the absorption photometric method cannot clarify the composition. In this study, we attempted to elucidate the composition of a sodium chlorite solution using absorption spectrophotometry and ion chromatography (IC). IC is excellent for qualitative and quantitative analysis of trace ions. Through this, we aimed to develop an evaluation method that allows anyone to easily determine the bactericidal power of sodium chlorite. We found that commercially available sodium chlorite solution is 80% pure, with the remaining 20% potentially containing sodium hypochlorite solution. In addition, when sodium chlorite solution became acidified, its absorption spectrum exhibited a peak at 365 nm. Sodium chlorite solution is normally alkaline, and it cannot be measured by the DPD method, which is only applicable under acidic conditions. The presence of a peak at 365 nm indicates that the acidic sodium chlorite solution contains species with oxidizing power. On the other hand, the IC analysis showed a gradual decrease in chlorite ions in the acidic sodium chlorite solution. These results indicate that chlorite ions may not react with this DPD reagent, and other oxidizing species may be present in the acidic sodium chlorite solution. In summary, when a sodium chlorite solution becomes acidic, chlorine-based oxidizing species produce an absorption peak at 365 nm. Sodium hypochlorite and sodium chlorite solutions have completely different IC peak profiles. Although there are still many problems to be solved, we believe that the use of IC will facilitate the elucidation of the composition of sodium chlorite solution and its sterilization mechanism.

Potential Involvement of DNA Methylation in Hybrid Sterility in Hermaphroditic Argopecten Scallops.

DNA methylation is an important epigenetic modification factor in regulating fertility. Corresponding process remains poorly investigated in hermaphroditic scallops. The interspecific F1 hybrids between the hermaphroditic bay scallops (Argopecten irradians) and Peruvian scallops (Argopecten purpuratus) exhibited significant heterosis in yield, but sterility in hybrids obstructs the utilization of the genetic resources. However, the determination mechanism of hybrid sterility in the hermaphroditic Argopecten scallops is still unclear. In this study, the effect of DNA methylation in the hybrid sterility of hermaphroditic Argopecten scallops was explored. The results showed that the mean methylation level was higher in sterile hybrids than fertile hybrids, especially on chromosome 11 of the paternal parent. A total of 61,062 differentially methylated regions (DMRs) were identified, containing 3619 differentially methylated genes (DMGs) and 1165 differentially methylated promoters that are located in the DMRs of CG sequence context. The hyper-methylated genes were enriched into five KEGG pathways, including ubiquitin-mediated proteolysis, ECM-receptor interaction, non-homologous end-joining, notch signaling, and the mismatch repair pathways. The DMGs might induce hybrid sterility by inhibition of oogenesis and egg maturation, induction of apoptosis, increased ROS, and insufficient ATP supply. Our results would enrich the determination mechanism of hybrid sterility and provide new insights into the utilization of the genetic resources of the interspecific hybrids.

Modulation of ultrathin nanosheet structure and nitrogen defects in graphitic carbon nitride for efficient photocatalytic bacterial inactivation

The efficient generation and utilization of ROSs is a key step in determining the achievement of safe drinking water by photocatalytic bacterial inactivation technology. Although graphitic carbon nitride (g-C3N4) serves as a green and promising photocatalyst for water disinfection, insufficient bacterial capturing capacity and serious charge recombination of pristine g-C3N4 extremely restrict its bactericidal activity. Herein, we develop a facile thermal exfoliation and thermal polymerization method to prepare the nitrogen-defective ultrathin g-C3N4 nanosheets (DUCN-500). Our results showed that ultrathin nanosheet structure greatly enhanced bacterial capturing capacity of g-C3N4 to increase the utilization efficiency of ROS, which contributed to the performance of DUCN-500 greatly outperforming bulk g-C3N4. The nitrogen defects increased ROS generation (·O2− and H2O2) by approximately 4.6 times, which was attributed to negative shift of the conduction band potential and rapid separation of charge carriers. The DUCN-500 could rapidly and completely inactivate Escherichia coli and Bacillus subtilis in real sewage under simulated solar irradiation, accompanied by good anti-interference capability and stability. Additionally, bacterial morphology destruction, the loss of antioxidant enzyme activity and the leakage of protein were proven to be the main mechanisms of photocatalytic sterilization. This study offers new insight into the rational design of efficient g-C3N4-based photocatalysts for water disinfection.

Molecular Mechanism of Male Sterility Induced by 60Co γ-Rays on Plutella xylostella (Linnaeus).

Plutella xylostella (Linnaeus) is one of the notorious pests causing substantial loses to numerous cruciferous vegetables across many nations. The sterile insect technique (SIT) is a safe and effective pest control method, which does not pollute the environment and does not produce drug resistance. We used proteomics technology and bioinformatics analysis to investigate the molecular mechanisms responsible for the effects of different doses of radiation treatment on the reproductive ability of male P. xylostella. A total of 606 differentially expressed proteins (DEPs) were identified in the 200 Gy/CK group, 1843 DEPs were identified in the 400 Gy/CK group, and 2057 DEPs were identified in the 400 Gy/200 Gy group. The results showed that after 200 Gy irradiation, the testes resisted radiation damage by increasing energy supply, amino acid metabolism and transport, and protein synthesis, while transcription-related pathways were inhibited. After 400 Gy irradiation, the mitochondria and DNA in the testis tissue of P. xylostella were damaged, which caused cell autophagy and apoptosis, affected the normal life activities of sperm cells, and greatly weakened sperm motility and insemination ability. Meanwhile, Western blotting showed that irradiation affects tyrosine phosphorylation levels, which gradually decrease with increasing irradiation dose.

High-Quality Genome Assembly and Genome-Wide Association Study of Male Sterility Provide Resources for Flax Improvement.

Flax is an economic crop with a long history. It is grown worldwide and is mainly used for edible oil, industry, and textiles. Here, we reported a high-quality genome assembly for "Neiya No. 9", a popular variety widely grown in China. Combining PacBio long reads, Hi-C sequencing, and a genetic map reported previously, a genome assembly of 473.55 Mb was constructed, which covers ~94.7% of the flax genome. These sequences were anchored onto 15 chromosomes. The N50 lengths of the contig and scaffold were 0.91 Mb and 31.72 Mb, respectively. A total of 32,786 protein-coding genes were annotated, and 95.9% of complete BUSCOs were found. Through morphological and cytological observation, the male sterility of flax was considered dominant nuclear sterility. Through GWAS analysis, the gene LUSG00017705 (cysteine synthase gene) was found to be closest to the most significant SNP, and the expression level of this gene was significantly lower in male sterile plants than in fertile plants. Among the significant SNPs identified in the GWAS analysis, only two were located in the coding region, and these two SNPs caused changes in the protein encoded by LUSG00017565 (cysteine protease gene). It was speculated that these two genes may be related to male sterility in flax. This is the first time the molecular mechanism of male sterility in flax has been reported. The high-quality genome assembly and the male sterility genes revealed, provided a solid foundation for flax breeding.

Sterilization mechanism and nanotoxicity of visible light-driven defective carbon nitride and UV-excited TiO2

The sterilization effect of photocatalysis and biotoxicity of nanomaterial catalysts have attracted high attention. In this study, the novel visible-driven defective carbon nitride (VL/DCN) system exhibits non-photoreactivation, non-toxic superior performance compared with traditional ultraviolet radiation (UV) and UV/titanium dioxide (UV/TiO2). The inactivation of antibiotic-resistant bacteria (ARB) by novel VL/DCN still reached 7 log within 4 h, and the reduction rates of aminoglycoside gene strB and tetracycline gene tetA exceeded 0.8 log and 1.2 log, respectively. Further, the sterilization mechanism and nanotoxicity were contrastively and systematically analyzed among above three systems as following. Firstly, in the VL/DCN system, reactive oxygen species (ROSs) generated from photocatalytic process leads to the destruction of cell membranes, resulting in dissolving out of potassium ion (K+), protein and cell membrane ATP content. Thus, resistant bacteria were completely inactivated and photoreactivation disappears. In contrast, the UV only acted on bacterial DNA and existed the light resurrection. The UV/TiO2 strictly dependent on ultraviolet light and can be used in limited scenarios. Secondly, in cell viability analysis by human lung cell line BEAS-2B experiments, the 10% inhibition of cell growth when DCN was 600 mg/L much lower than 28% inhibition of cell growth when TiO2 was only 200 mg/L. The expression of pro-inflammatory cytokines ((Interleukin, IL) -6), IL-8, IL-1β) under the effect of DCN was 1.5-fold, 5.7-fold and 3.7-fold lower than TiO2, respectively. Meanwhile, DCN induced cells to produce less ROSs, malondialdehyde (MDA), and more superoxide dismutase (SOD). Above results demonstrated that DCN has far lower cytotoxicity than TiO2. This study provides theoretical support for the application of photocatalytic sterilization technology and the exploration of the toxicity of nanomaterials.

Potential candidate genes and pathways related to cytoplasmic male sterility in Dianthus spiculifolius as revealed by transcriptome analysis.

We introduced the candidate gene DsHSP70 into Arabidopsis thaliana, resulting in male gametophyte sterility and abnormal degeneration of sepals and petals. Cytoplasmic male sterility (CMS) is a useful tool for hybrid production. However, the regulatory mechanism of CMS in Dianthus spiculifolius remains unclear. In this study, we investigated whether male-sterile line of D. spiculifolius has a malformed tapetum and fails to produce normal fertile pollen. RNA sequencing technology was used to compare the gene expression patterns of the D. spiculifolius male-sterile line and its male fertility maintainer line during anther development. A total of 12,365 differentially expressed genes (DEGs) were identified, among which 1765 were commonly expressed in the S1, S2 and S3 stages. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses indicated that these DEGs were mainly involved in oxidation-reduction processes, signal transduction and programmed cell death. Additionally, weighted correlation network analysis (WGCNA) showed that three modules may be related to male sterility. A putative regulatory pathway for the male sterility traits was constructed based on the reproductive development network. After introducing the candidate DsHSP70 gene into Arabidopsis thaliana, we found that overexpressing plants showed anther abortion and shorter filaments, and accompanied by abnormal degeneration of sepals and petals. In summary, our results identified potential candidate genes and pathways related to CMS in D. spiculifolius, providing new insights for further research on the mechanism of male sterility.