Transcriptomic Screening of Alternaria oxytropis Isolated from Locoweed Plants for Genes Involved in Mycotoxin Swaisonine Production.

Locoweed is a collective name for a variety of plants, such as Oxytropis and Astragalus L. When these plants are infected by some fungi or endophytes, they will produce an alkaloid (swainsonine) that is harmful to livestock. Chronic toxicity characterized by neurological disorders occurs in livestock overfed on locoweed, and swainsonine (SW) is considered a major toxic component. The mechanism of the SW synthesis of endophytic fungi from locoweed remains unknown. In order to further discover the possible synthetic pathway of SW, in this study, a mycotoxin (SW) producer, Alternaria oxytropis isolate, UA003, isolated from Locoweed plants, and its mutant were subjected to transcriptomic analyses to ascertain the genes involved in the synthesis of this toxin. Mutant strain A. oxytropis E02 was obtained by ethyl methanesulfonate (EMS) mutagenesis treatment, and the strains were sequenced with different culture times for transcriptomic analysis and screening of differentially expressed genes. The results show a highly significant (p < 0.01) increase in SW yield in the A. oxytropis E02 strain obtained by EMS mutagenesis treatment compared to A. oxytropis UA003. A total of 637 differentially expressed genes were screened by transcriptome sequencing analysis, including 11 genes potentially associated with SW biosynthesis. These genes were screened using GO and KEGG data annotation and analysis. Among the differential genes, evm.TU.Contig4.409, evm.TU.Contig19.10, and evm.TU.Contig50.48 were associated with L-lysine biosynthesis, the L-pipecolic acid pathway, and the α-aminoadipic acid synthesis pathway. This study provides new insights to elucidate the mechanism of SW synthesis of endophytic fungi in locoweed and provides data support for further exploration of A. oxytropis genomics studies.

Construction of Yeast One-Hybrid Library of Alternaria oxytropis and Screening of Transcription Factors Regulating swnK Gene Expression.

The indolizidine alkaloid-swainsonine (SW) is the main toxic component of locoweeds and the main cause of locoweed poisoning in grazing animals. The endophytic fungi, Alternaria Section Undifilum spp., are responsible for the biosynthesis of SW in locoweeds. The swnK gene is a multifunctional complex enzyme encoding gene in fungal SW biosynthesis, and its encoding product plays a key role in the multistep catalytic synthesis of SW by fungi using pipecolic acid as a precursor. However, the transcriptional regulation mechanism of the swnK gene is still unclear. To identify the transcriptional regulators involved in the swnK gene in endophytic fungi of locoweeds, we first analyzed the upstream non-coding region of the swnK gene in the A. oxytropis UA003 strain and predicted its high transcriptional activity region combined with dual-luciferase reporter assay. Then, a yeast one-hybrid library of A. oxytropis UA003 strain was constructed, and the transcriptional regulatory factors that may bind to the high-transcriptional activity region of the upstream non-coding region of the swnK gene were screened by this system. The results showed that the high transcriptional activity region was located at -656 bp and -392 bp of the upstream regulatory region of the swnK gene. A total of nine candidate transcriptional regulator molecules, including a C2H2 type transcription factor, seven annotated proteins, and an unannotated protein, were screened out through the Y1H system, which were bound to the upstream high transcriptional activity region of the swnK gene. This study provides new insight into the transcriptional regulation of the swnK gene and lays the foundation for further exploration of the regulatory mechanisms of SW biosynthesis in fungal endophytic locoweeds.

Alterations of microbiota and metabolites in the feces of calves with diarrhea associated with rotavirus and coronavirus infections.

The changes in the composition of intestinal microbiota and metabolites have been linked to digestive disorders in calves, especially neonatal calf diarrhea. Bovine rotavirus (BRV) and bovine coronavirus (BCoV) are known to be the primary culprits behind neonatal calf diarrhea. In this study, we analyzed changes in the fecal microbiota and metabolites of calves with neonatal diarrhea associated with BRV and BCoV infection using high-throughput 16S rRNA sequencing and metabolomics technology. The microbial diversity in the feces of calves infected with BRV and BCoV with diarrhea decreased significantly, and the composition changed significantly. The significant increase of Fusobacterium and the reductions of some bacteria genera, including Faecalibacterium, Bifidobacterium, Ruminococcus, Subdoligranulum, Parabacteroides, Collinsella, and Olsenella, etc., were closely related to diarrhea associated with BRV and BCoV infection. Metabolites in the feces of BRV and BCoV-infected calves with diarrhea were significantly changed. Phosphatidylcholine [PC; 16:1(9 Z)/16:1(9 Z)], lysophosphatidylethanolamine (LysoPE; 0:0/22:0), lysophosphatidylcholine (LysoPC; P-16:0) and LysoPE (0:0/18:0) were significantly higher in the feces of BRV-infected calves with diarrhea. In contrast, some others, such as desthiobiotin, were significantly lower. BRV infection affects glycerophospholipid metabolism and biotin metabolism in calves. Two differential metabolites were significantly increased, and 67 differential metabolites were significantly reduced in the feces of BCoV-infected calves with diarrhea. Seven significantly reduced metabolites, including deoxythymidylic acid (DTMP), dihydrobiopterin, dihydroneopterin triphosphate, cortexolone, cortisol, pantetheine, and pregnenolone sulfate, were enriched in the folate biosynthesis, pantothenate and CoA biosynthesis, pyrimidine metabolism, and steroid hormone biosynthesis pathway. The decrease in these metabolites was closely associated with increased harmful bacteria and reduced commensal bacteria. The content of short-chain fatty acids (SCFAs) such as acetic acid and propionic acid in the feces of BRV and BCoV-infected calves with diarrhea was lower than that of healthy calves, which was associated with the depletion of SCFAs-producing bacteria such as Parabacteroides, Fournierella, and Collinsella. The present study showed that BRV and BCoV infections changed the composition of the calf fecal microbiota and were associated with changes in fecal metabolites. This study lays the foundation for further revealing the roles of intestinal microbiota in neonatal calf diarrhea associated with BRV and BCoV infection.

Demulsification of oily wastewater using a nano carbon black modified with polyethyleneimine.

In this work, nano carbon black was modified with polyethyleneimine (CB-PEI) under an ultrasonic field. The obtained product was used as a demulsifier to break oily wastewater. Morphology, structure, and chemical composition of CB-PEI were systematically analyzed. Bottle test was carried out to evaluate the influence of dosage, pH value and salinity on the demulsification efficiency of the emulsion. The results showed that the light transmittance of water phase (TSW) after the demulsification was 79.1% and corresponding oil removal rate (ORR) could reach up to 99.4% with 60 mg/L of CB-PEI at ambient temperature for 30 min. In addition, the possible demulsification mechanism was explored by dynamic interface tension (IFT), elasticity modulus, wettability, self-assemble of interfacial membrane, zeta potential and micrograph analysis. It indicated that CB-PEI had an appropriate amphiphilicity and good interfacial activity, which could improve it quickly transfer to the oil-water interface and result in the oil-water separation. The current work provides a simple method to prepare a demulsifier with excellent performance, so it has a good application prospect for the treatment of oil-water emulsions.

Comparison of lipid deposition of intramuscular preadipocytes in Tan sheep co-cultured with satellite cells or alone.

The purpose of this study was to investigate the effect of the skeletal muscle satellite cells (SMSCs) on the lipid deposition of the intramuscular preadipocytes (IMPs) in a co-culture system of the Tan sheep cells. The SMSCs and IMPs from Tan sheep were separated and cultured. After the two kinds of cells were separated and cultured, they were inoculated onto a transwell cell chamber co-culture plate for co-cultivation. When the cell density reached more than 90%, the cells were induced to differentiate. After the induction of the SMSCs differentiation for 8 days, the level of the IMPs differentiation and the expression levels of the differentiation marker genes and the key enzymes of the lipid metabolism were assessed. The results showed that the number and area of the lipid droplets in the IMPs in the co-culture system were significantly reduced compared to those in the IMPs culture alone (p < 0.05). Meanwhile, the expression levels of the PPARγ, c/EBPα, ACC, FAS mRNA in the IMPs were significantly decreased (p < 0.05); the expression level of aP2 mRNA was decreased, but the difference was not significant (p > 0.05).These findings indicate that the SMSCs of the Tan sheep in the co-culture system inhibited the lipid deposition by the IMPs.

[Impacts of ODF2 gene knockdown on the sperm motility and fertility of male mice].

OBJECTIVE: To investigate the knockdown of the outer dense fiber protein 2 (ODF2) gene on the sperm motility and fertility of male mice. METHODS: We constructed three knockdown vectors with the target gene ODF2 and one control vector without the target gene. After infecting ICR mice, we determined the vector with the best knockdown effect by RT-PCR and Western blot and reinfected the mice with it. Then we obtained and analyzed the sperm motility parameters, pathological changes of the testis issue, and the litter size of the mice with gene knockdown. RESULTS: Compared with the normal controls, the mice infected with the vector with the best knockdown effect showed significantly decreased sperm motility parameters, pathomorphological abnormalities of the testis, and a reduced litter size (10.86 ± 1.28 vs 12.72 ± 2.05, P = 0.001). CONCLUSION: Decreased expression of the ODF2 gene deceases sperm motility parameters, impairs the morphology of the testis and affects the fertility of male mice.

Long non­coding RNA HCG11 suppresses the malignant phenotype of non­small cell lung cancer cells by targeting a miR­875/SATB2 axis.

Long non­coding RNAs (lncRNAs) are involved in the development and progression of a variety of diseases. However, the role of the lncRNA HLA complex group 11 (HCG11) in non­small cell lung cancer (NSCLC) remains unclear. The present study showed that the expression levels of HCG11 were reduced in tumor tissues compared with adjacent normal tissues, and similar results were obtained in experiments using lung cancer cell lines. Additionally, patients with high HCG11 expression had an increased survival rate compared with patients with low HCG11 expression. Further studies have shown that overexpression of HCG11 inhibited NSCLC cell proliferation in vitro and in vivo. Interestingly, it was observed that HCG11 expression was negatively associated with the expression levels of oncogenic microRNA­875 (miR­875) in patient specimens. Specifically, HCG11 served as a sponge of miR­875. Notably, it was determined that special AT­rich sequence­binding protein 2 (SATB2) was a direct target gene of miR­875, and overexpression of miR­875 largely abrogated the effects of HCG11 in NSCLC cells. In conclusion, HCG11 was shown to suppress the malignant properties of NSCLC cells by targeting a miR­875/SATB2 axis, and may therefore be a promising target for the treatment of NSCLC.

CHAF1B knockdown blocks migration in a hepatocellular carcinoma model.

The roles and model of action of the chromatin assembly complex factor-1B (CHAF1B) gene in liver cancer have not been fully elucidated. The CHAF1B gene in human hepatocellular carcinoma cell line HUH-7 was knocked down using a lentivirus and the transfected cells were assayed for migration and invasion abilities and cell cycle arrest using the scratch wound healingand Transwell assays as well as flow cytometry, respectively. Cells transfected with an empty vector were used as the control. The expression of genes was profiled. Models were constructed using CHAF1B-knockdown cells and investigated for tumor growth and pathological changes. Our experiments revealed that the knockdown of the CHAF1 gene reduced the invasion and migration ability of HUH-7 cells. Gene expression profiling revealed that after knockdown, PSMB6, SLC30A7, SMC3, TWF2 and BLM genes had the most marked changes as compared with the control. Western blot and RT-PCR analyses revealed that following the knockdown of the CHAF1B gene, protein and mRNA levels of the PSMB6, SLC30A7 and SMC3 genes were significantly upregulated, while those of the BLM and TWF2 genes were significantly downregulated. In the HUH-7-knockdown cells, there were significantly fewer G0/G1 cells and more S1 cells as compared with the control (36.10 vs. 54.10% and 59.7 vs. 40.8%, respectively), while the number of G2/M cells was similar (4.20 vs. 5.10%). The volumes of the tumors were similar between those injected with the empty vector and control, but were significantly smaller in the knockdown models, suggesting that the knockdown of the CHAF1B gene inhibited tumor growth. H&E staining revealed that tumors were developed in mice in all groups.

Attenuation of enoyl coenzyme A hydratase 1 expression in colorectal cancer cells using small interfering RNA inhibits cell proliferation and migration.

Colorectal cancer is one of the most commonly diagnosed types of cancer and is a leading cause of cancer-associated mortality worldwide. Short chain enoyl coenzyme A hydratase 1 (ECHS1) is an important gene involved in the mitochondrial fatty acid ß-oxidation pathway. In addition, ECHS1 has been implicated in a variety of cancers, including breast, prostate, colon and liver cancer. The aim of the present study was to examine the expression of ECHS1 in the human HCT-8 colorectal cancer cell line. The results showed that ECHS1 expression was significantly increased in poorly-differentiated cells compared with that in well-differentiated cells. In order to further investigate the functions of ECHS1 in colorectal cancer cells, a stably transfected HCT-8 cell line expressing small interfering (si)RNA targeting the ECHS1 gene was established. The expression of the ECHS1 siRNA was found to reduce ECHS1 protein levels in ECHS1-silenced cells by >40%. Cell proliferation and cell migration of the siECHS1 cells were characterized using Cell Counting Kit-8 and Transwell assays, respectively, the results of which showed that the constitutive knockdown of the ECSH1 gene in HCT-8 cells significantly inhibited cell proliferation and migration. Furthermore, decreased levels of Akt and glycogen synthase kinase (GSK)3ß phosphorylation were observed in ECHS1-silenced HCT-8 cells compared with that of parental or pU6 empty vector-transfected cells. In conclusion, the results of the present study suggested that ECHS1 may have an important role in colorectal cancer cell proliferation and migration via activation of Akt- and GSK3ß-associated signaling pathways.

Complete mitochondrial genome of a new subspecies of the blue sheep, Pseudois nayaur (Cetartiodactyla: Caprinae) from Helan Mountain in China.

The population of blue sheep, Pseudois nayaur, from Helan Mountain in China is considered as a new subspecies. We first determined and annotated its complete mitochondrial genome. The mitogenome is 16,795 bp in length, consisting of 13 protein-coding genes, 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes and a control region. As in other mammals, most mitochondrial genes are encoded on the heavy strand, except for ND6 and eight tRNA genes, which are encoded on the light strand. Its overall base composition is A: 33.2%, T: 26.6%, C: 26.8% and G: 13.3%. The complete mitogenome of the new subspecies of P. nayaur could provide an important data to further explore the taxonomic status of the subspecies.

Effects of over-expression of ANXA10 gene on proliferation and apoptosis of hepatocellular carcinoma cell line HepG2.

The effects of over-expression of ANXA10 gene on proliferation and apoptosis of hepato-cellular carcinoma cell line HepG2 were elucidated. The human ANXA10 gene was subcloned into the lentiviral vector, PGC-FU, to generate the lentiviral expression vector, PGC-FU-ANXA10. The corrected ANXA10 was confirmed by endoenzyme digestion, and sequencing. Recombinant lentiviruses were produced by 293T cells following the co-transfection of PGC-FU-ANXA10 with the packaging plasmids pHelper1.0 and pHelper2.0. The resulting recombinant lentiviruses carrying ANXA10 were then used to infect human embryonic kidney epithelial cells, and lentiviral particles were produced. The ANXA10 expression in 293T cells was detected by using fluorescent microscope and Western blotting. HepG2 cells were infected, and divided into PGC-Fu-ANXA10 group, PGC-Fu group and HepG2 cell group. The changes of ANXA10 mRNA and protein expression were detected by using RT-PCR and Western blotting respectively. Flow cytometry and MTT assay were performed to examine the changes in cell apoptosis and proliferation respectively. The recombinant PGC-FU-ANXA10 vector was successfully constructed, the ANXA10 protein was detected by using Western blotting, and virus titer was 2×10(8) TU/mL. The recombinant lentiviruses were effectively infected into HepG2 cells in vitro and the infection efficiency was 70%. At 72 h after infection, the ANXA10 mRNA and protein expression levels in PGC-Fu-ANXA10 group were significantly higher than in PGC-Fu group and HepG2 cell group (P<0.05); the in vitro growth inhibition rate of HepG2 cells in PGC-Fu-ANXA10 group was 24.65%, significantly higher than that in PGC-Fu group and HepG2 cell group (P<0.05), but there was no significant difference between PGC-Fu group and HepG2 cell group; the apoptosis rate in PGC-Fu-ANXA10 group, PGC-Fu group and HepG2 cell group was (51.92±1.41)%, (19.00±1.12)% and (3.59±0.89)% respectively. The apoptosis rate in PGC-Fu-ANXA10 group was significantly higher than in PGC-Fu group and HepG2 cell group (P<0.05). The recombinant lentiviruses PGC-FU-ANXA10 were constructed successfully and infected into HepG2 cells. The overexpression of ANXA10 gene can significantly inhibit proliferation and promote apoptosis of HepG2 cells in vitro.

Swainsonine-producing fungal endophytes from major locoweed species in China.

Locoweeds including the toxic species of Astragalus spp and Oxytropis spp. are widely distributed in the western region of China and result in a chronic neurological disease known as locoism in animals. To determine the presence of swainsonine-producing fungal endophyte of major locoweed species in China, endophytes were isolated from 8 locoweed species that including A. variabilis, A. strictus, O. glacialis, O. kansuensis, O. ochrocepala, O. sericopetala, O. glabra and O. latibracteata. Seven species of locoweed were confirmed contain substantial amounts of swainsonine and infect swainsonine-producing fungal endophyte. These endophytes were classified as Undifilim oxytropis according to the fungal morphology and phylogenetic analysis based on sufficient ITS sequences. PCR-RFLP analysis of IGS region showed that the interspecific or intraspecific variations were present among the endophytes from different locoweed species.

Reconstruction of damaged cornea by autologous transplantation of epidermal adult stem cells.

PURPOSE: It is crucial for the treatment of severe ocular surface diseases such as Stevens-Johnson syndrome (SJS) and ocular cicatricial pemphigoid (OCP) to find strategies that avoid the risks of allograft rejection and immunosuppression. Here, we report a new strategy for reconstructing the damaged corneal surface in a goat model of total limbal stem cell deficiency (LSCD) by autologous transplantation of epidermal adult stem cells (EpiASC). METHODS: EpiASC derived from adult goat ear skin by explant culture were purified by selecting single cell-derived clones. These EpiASC were cultivated on denuded human amniotic membrane (HAM) and transplanted onto goat eyes with total LSCD. The characteristics of both EpiASC and reconstructed corneal epithelium were identified by histology and immunohistochemistry. The clinical characteristic of reconstructed corneal surface was observed by digital camera. RESULTS: Ten LSCD goats (10 eyes) were treated with EpiASC transplantation, leading to the restoration of corneal transparency and improvement of postoperative visual acuity to varying degrees in 80.00% (8/10) of the experimental eyes. The corneal epithelium of control groups either with HAM transplantation only or without any transplantation showed irregular surfaces, diffuse vascularization, and pannus on the entire cornea. The reconstructed corneal epithelium (RCE) expressed CK3, CK12, and PAX-6 and had the function of secreting glycocalyx-like material (AB-PAS positive). During the follow-up period, all corneal surfaces remained transparent and there were no serious complications. We also observed that the REC expressed CK1/10 weakly at six months after operation but not at 12 months after operation, suggesting that the REC was derived from grafted EpiASC. CONCLUSIONS: Our results showed that EpiASC repaired the damaged cornea of goats with total LSCD and demonstrated that EpiASC can be induced to differentiate into corneal epithelial cell types in vivo, which at least in part correlated with down-regulation of CK1/10 and upregulation of PAX-6.

Reconstruction of corneal epithelium with cryopreserved corneal limbal stem cells in a goat model.

We describe a procedure to construct an artificial corneal epithelium from cryopreserved limbal stem cells (LSCs) for corneal transplantation. The LSCs were separated from limbal tissue of male goats. The primary LSCs were identified by flow cytometry and were expanded. They were examined for stem cell-relevant properties and cryopreserved in liquid nitrogen. Cryopreserved LSCs were thawed and then transplanted onto human amniotic membrane, framed on a nitrocellulose sheet, to construct corneal epithelium sheets. The artificial corneal epithelium was transplanted into the right eye of pathological models of total limbal stem cell deficiency (LSCD). Then, the effects of reconstruction were evaluated by clinical observation and histological examination. Polymerase chain reaction analysis was used to detect the SRY gene. The data showed that transplantation of cryopreserved LSCs, like fresh LSCs, successfully reconstructed damaged goat corneal surface gradually, but the SRY gene expression from male goat cells could only be detected in the first 2 months after transplantation. The therapeutic effect of the transplantation may be associated with the inhibition of inflammation-related angiogenesis after transplantation of cryopreserved LSCs. This study provides the first line of evidence that cryopreserved LSCs can be used for reconstruction of damaged corneas, presenting a remarkable potential source for transplantation in the treatment of corneal disorders.