The mRNA expression of P450 aromatase, gonadotropin beta-subunits and FTZ-F1 in the orange-spotted grouper (Epinephelus Coioides) during 17alpha-methyltestosterone-induced precocious sex change

The orange-spotted grouper Epinephelus coioides is a protogynous hermaphroditic fish, but the physiological basis of its sex change remains largely unknown. In the present study, the 2-year-old orange-spotted grouper was induced to change sex precociously by oral administration of 17alpha-methyltestosterone (MT, 50 mg/Kg diet, twice a day at daily ration of 5% bodyweight) for 60 days. The serum testosterone levels were significantly elevated after MT treatment for 20 and 40 days as compared to control, but the levels of serum estradiol (E(2)) remained unchanged. The expression of P450aromA in the gonad significantly decreased after MT treatment for 20, 40, and 60 days. Accordingly, the enzyme activity of gonadal aromatase was also lower. The expression of FSHbeta subunit in the pituitary was significantly decreased after MT treatment for 20 days, but returned to the control levels after 40 and 60 days; however, the expression of LHbeta subunit was not altered significantly by MT treatment. The expression of FTZ-F1 in the gonad also decreased significantly in response to MT treatment for 40 and 60 days, but its expression in the pituitary was not altered significantly. Interestingly, when tested in vitro on ovarian fragments, MT had no direct effect on the expression of P450aromA and FTZ-F1 as well as the activity of gonadal aromatase, suggesting that the inhibition of gonadal P450aromatase and FTZ-F1 by MT may be mediated at upper levels of the brain-pituitary-gonadal axis. Taken together, these results indicated that FSH, P450aromA, FTZ-F1, and serum testosterone are associated with the MT-induced sex change of the orange-spotted grouper, but the cause-effect relationship between these factors and sex change in this species remains to be characterized.     

Different probiotic properties for Lactobacillus fermentum strains isolated from swine and poultry

Systematic procedures were used to evaluate the probiotic properties of Lactobacillus fermentum (L. fermentum) strains isolated from swine and poultry. The major properties included their capabilities to adhere to the intestinal epithelium of swine and poultry, the inhibition on pathogenic bacteria, and their tolerance to the gastric juice and bile salts. Results showed that L. fermentum strains from poultry digestive tract showed better adherence to the swine intestine and chicken crop epithelial cells as compared to those strains from the swine origin. In addition, six strains from poultry and one strain from swine showed adhesion specificity to their own intestinal epithelium. Four poultry isolates and one swine isolate were able to adhere to the epithelial cells from both swine and chicken. For gastric juice and bile tolerance, most of the strains isolated from swine or poultry were acid tolerant but less strains were bile intolerant. The spent culture supernatant (SCS) of these L. fermentum strains showed antagonistic effect against the indicator bacteria, such as Escherichia coli, Salmonella spp., Shigella sonnei and some enterotoxigenic Staphylococcus aureus. From the above studies, some L. fermentum strains isolated from poultry were found to have the probiotic properties required for use in animal feed supplement. This study suggested that poultry digestive tract may serve as potential source for the isolation of probiotic lactic acid bacteria.     

Biodegradability of tannin-containing wastewater from leather industry

Tannins occur commonly in the wastewaters from forestry, plant medicine, paper and leather industries. The treatment of this kind of wastewaters, including settling and biodegradation, is usually difficult because tannins are highly soluble in water and would inhibit the growth of microorganisms in activated sludge. The objective of this study is to investigate biodegradability of tannin-containing wastewaters, so as to characterize the pollution properties of such wastewaters and provide a reference for their biological treatment in wastewater treatment plants. The research was typified by using the wastewater collected from vegetable tanning process in leather industry. A model was developed to describe the activated sludge process, and the biodegradation kinetics of vegetable tanning wastewater (VET wastewater) was studied. It was found that the biodegradability of tannin-containing wastewater varies heavily with the content of tannins in wastewater. The biodegradation of VET wastewater with tannin content around 4,900 mg/l occurred inefficiently due to the inhibition of tannins to the activated sludge process, and only 34.7% of biodegradation extent was reached in 14 days of incubation. The optimal biodegradability of VET wastewater was observed when its tannin content was diluted to 490 mg/l, where the COD and tannin removals reached 51.3% and 45.1% respectively in 6 days. Hence, it is suggested that a proper control of tannin content is necessary to achieve an effective biodegradation of tannin-containing wastewaters in wastewater treatment plants.     

利用免疫抑制小鼠模型检测真菌病毒对黄曲霉菌致病力影响

【目的】构建用于比较黄曲霉（Aspergillus flavus,A. flavus）菌株之间致病力差异的小鼠感染模型,并利用该模型评价真菌病毒AfPV1对宿主A. flavus致病力的影响。【方法】用不同浓度环磷酰胺腹腔注射Institute of Cancer Research （ICR）小鼠,根据白细胞的数量判断小鼠免疫抑制程度;通过滴鼻和尾静脉两种感染方法接种不同浓度的A. flavus孢子量,统计14 d以内小鼠的死亡率,确定A. flavus最佳的孢子接种量;通过小鼠组织的菌落负荷量以及肺部组织的病理观察,确定A. flavus感染是否成功;最后利用该小鼠模型评价真菌病毒AfPV1对寄主A. flavus致病力的影响。【结果】腹腔注射环磷酰胺的浓度为250 mg/kg时,能够达到免疫抑制水平;小鼠组织真菌负荷和病理组织切片观察显示A. flavus成功感染接种的ICR小鼠组织;在滴鼻接种模型中,A. flavus的孢子接种量为40μL（1×10⁶CFU/mL）时比较合适评价A. flavus菌株之间的差异;在尾静脉接种的模型中,A. flavus的孢子...     

RNA-Seq Reveals the Effect of Ethylene on the Volatile Organic Components (VOCs) of Cavendish Banana at Different Post-harvesting Stages

Aroma serves as one of the decisive factors influencing the value of banana commodities. Most of characteristic volatile organic components (VOCs) are formed during post-harvesting. However, the changing of VOCs of banana at different post-harvesting stages remain ambiguous. In this study, the VOCs of Cavendish banana for the four typical post-harvesting stages (green stage/half of yellow stage/yellow ripening stage/over ripening stage) are clarified using headspace solid phase micro-extraction (HS-SPME), combined with gas chromatography-mass spectrometry (GC–MS). The results inferred that the relative content of branched-chain esters such as acetate and butyrate, which form the main contributors of aroma in bananas, is higher in the T2 and T3 stages. Further, RNA-Seq technology was employed to clarify the formation mechanism of banana aroma in the post-harvesting stage. The MaTGL4 gene of the linoleic acid metabolism pathway and the MaBCAT3 and MaBCAT5 genes of the valine, leucine and isoleucine degradation pathway in banana suggest the expression is active late in the ripening stage, and the upregulated expression of these genes is analogous to the formation of aroma components such as branched-chain esters and hexenal. The above results not only provide baseline data on the differences in physical and chemical properties of VOCs in various post-harvesting stages of banana production, but also provide theoretical guidance facilitating the subsequent improvement of the commercial value of bananas through genetic improvement.

     

microRNA-21-5p from M2 macrophage-derived extracellular vesicles promotes the differentiation and activity of pancreatic cancer stem cells by mediating KLF3

Cell Biology and Toxicology - Given the fact that tumor-associated macrophage-derived extracellular vesicles (EVs) are attributable to tumor aggressiveness, this research intends to decode the...     

Diversity of the Sediment Microbial Community in the Aha Watershed (Southwest China) in Response to Acid Mine Drainage Pollution Gradients

Located in southwest China, the Aha watershed is continually contaminated by acid mine drainage (AMD) produced from upstream abandoned coal mines. The watershed is fed by creeks with elevated concentrations of aqueous Fe (total Fe > 1 g/liter) and SO₄²⁻ (>6 g/liter). AMD contamination gradually decreases throughout downstream rivers and reservoirs, creating an AMD pollution gradient which has led to a suite of biogeochemical processes along the watershed. In this study, sediment samples were collected along the AMD pollution sites for geochemical and microbial community analyses. High-throughput sequencing found various bacteria associated with microbial Fe and S cycling within the watershed and AMD-impacted creek. A large proportion of Fe- and S-metabolizing bacteria were detected in this watershed. The dominant Fe- and S-metabolizing bacteria were identified as microorganisms belonging to the genera Metallibacterium, Aciditerrimonas, Halomonas, Shewanella, Ferrovum, Alicyclobacillus, and Syntrophobacter. Among them, Halomonas, Aciditerrimonas, Metallibacterium, and Shewanella have previously only rarely been detected in AMD-contaminated environments. In addition, the microbial community structures changed along the watershed with different magnitudes of AMD pollution. Moreover, the canonical correspondence analysis suggested that temperature, pH, total Fe, sulfate, and redox potentials (E_h) were significant factors that structured the microbial community compositions along the Aha watershed.