Histone Deacetylase UvHST2 Is a Global Regulator of Secondary Metabolism in Ustilaginoidea virens.

Ustilaginoidea virens, the causal agent of rice false smut, produces a large amount of mycotoxins, including ustilaginoidins and sorbicillinoids. However, little is known about the regulatory mechanism of mycotoxin biosynthesis inU. virens. Here, we demonstrate that the NAD+-dependent histone deacetylase UvHST2 negatively regulates ustilaginoidin biosynthesis. UvHst2 knockout caused retarded hypha growth and reduced conidiation and pathogenicity inU. virens. Transcriptome analysis revealed that the transcription factor genes, transporter genes, and other tailoring genes in eight biosynthetic gene clusters (BGCs) including ustilaginoidin and sorbicillinoid BGCs were upregulated in ΔUvhst2. Interestingly, the UvHst2 deletion affects alternative splicing. Metabolomics revealed that UvHST2 negatively regulates the biosynthesis of various mycotoxins including ustilaginoidins, sorbicillin, ochratoxin B, zearalenone, and O-M-sterigmatocystin. Combined transcriptome and metabolome analyses uncover that UvHST2 positively regulates pathogenicity but negatively modulates the expression of BGCs involved in secondary metabolism. Collectively, UvHST2 functions as a global regulator of secondary metabolism inU. virens.

Immobilization of bacterial mixture of Klebsiella variicola FH-1 and Arthrobacter sp. NJ-1 enhances the bioremediation of atrazine-polluted soil environments.

In this study, the effects of the immobilized bacterial mixture (IM-FN) of Arthrobacter sp. NJ-1 and Klebsiella variicola strain FH-1 using sodium alginate-CaCl2 on the degradation of atrazine were investigated. The results showed that the optimal ratio of three types of carrier materials (i.e., rice straw powder, rice husk, and wheat bran) was 1:1:1 with the highest adsorption capacity for atrazine (i.e., 3774.47 mg/kg) obtained at 30°C. On day 9, the degradation efficiency of atrazine (50 mg/L) reached 98.23% with cell concentration of 1.6 × 108 cfu/ml at pH 9 and 30°C. The Box-Behnken method was used to further optimize the culture conditions for the degradation of atrazine by the immobilized bacterial mixture. The IM-FN could be reused for 2-3 times with the degradation efficiency of atrazine maintained at 73.0% after being stored for 80 days at 25°C. The population dynamics of IM-FN was explored with the total soil DNA samples specifically analyzed by real-time PCR. In 7 days, the copy numbers of both PydC and estD genes in the IM-FN were significantly higher than those of bacterial suspensions in the soil. Compared with bacterial suspensions, the IM-FN significantly accelerated the degradation of atrazine (20 mg/kg) in soil with the half-life shortened from 19.80 to 7.96 days. The plant heights of two atrazine-sensitive crops (wheat and soybean) were increased by 14.99 and 64.74%, respectively, in the soil restored by immobilized bacterial mixture, indicating that the IM-FN significantly reduced the phytotoxicity of atrazine on the plants. Our study evidently demonstrated that the IM-FN could significantly increase the degradation of atrazine, providing a potentially effective bioremediation technique for the treatment of atrazine-polluted soil environment and providing experimental support for the wide application of immobilized microorganism technology in agriculture.

The C2H2 Transcription Factor SsZFH1 Regulates the Size, Number, and Development of Apothecia in Sclerotinia sclerotiorum.

Sclerotinia sclerotiorum is a notorious phytopathogenic Ascomycota fungus with a host range of >600 plant species worldwide. This homothallic Leotiomycetes species reproduces sexually through a multicellular apothecium that produces and releases ascospores. These ascospores serve as the primary inoculum source for disease initiation in the majority of S. sclerotiorum disease cycles. The regulation of apothecium development for this pathogen and other apothecium-producing fungi remains largely unknown. Here, we report that a C2H2 transcription factor, SsZFH1 (zinc finger homologous protein), is necessary for the proper development and maturation of sclerotia and apothecia in S. sclerotiorum and is required for the normal growth rate of hyphae. Furthermore, ΔSszfh1 strains exhibit decreased H2O2 accumulation in hyphae, increased melanin deposition, and enhanced tolerance to H2O2 in the process of vegetative growth and sclerotia formation. Infection assays on common bean leaves, with thin cuticles, and soybean and tomato leaves, with thick cuticles, suggest that the deletion of Sszfh1 slows the mycelial growth rate, which in turn affects the expansion of leaf lesions. Collectively, our results provide novel insights into a major fungal factor mediating maturation of apothecia with additional effects on hyphae and sclerotia development.

Dynamic monitoring of serum liver function indexes in patients with COVID-19.

BACKGROUND: Some patients with the novel 2019 coronavirus disease (COVID-19) display elevated liver enzymes. Some antiviral drugs that can be used against COVID-19 are associated with a risk of hepatotoxicity. AIM: To analyze the clinical significance of the dynamic monitoring of the liver function of patients with COVID-19. METHODS: This was a retrospective study of patients diagnosed with COVID-19 in January and February 2020 at the Department of Infection, Shantou Central Hospital. The exclusion criteria for all patients were: (1) History of chronic liver disease; (2) History of kidney disease; (3) History of coronary heart disease; (4) History of malignancy; or (5) History of diabetes. The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyltransferase, and total bilirubin of patients with COVID-19 were measured on days 1, 3, 7 and 14 after admission, and compared to non-COVID-19 patents. RESULTS: Twelve patients with COVID-19 (seven men and five women) and twelve controls (eight men and four women) were included. There were one, two, and nine patients with severe, mild, and moderate COVID-19, respectively. There were no differences in age and sex between the two groups (both P > 0.05). No significant differences were found in albumin, ALT, AST, γ-glutamyltransferase, or total bilirubin between the controls and the patients with COVID-19 on day 1 of hospitalization (all P > 0.05). Serum albumin showed a decreasing trend from days 0 to 7 of hospitalization, reaching the lowest level on day 7. Total bilirubin was higher on day 3 than on day 7. ALT, AST, and γ-glutamyltransferase did not change significantly over time. The severe patient was observed to have ALT levels of 67 U/L and AST levels of 75 U/L on day 7, ALT of 71 U/L and AST of 35 U/L on day 14, and ALT of 210 U/L and AST of 123 U/L on day 21. CONCLUSION: Changes in serum liver function indicators are not obvious in the early stage of COVID-19, but clinically significant changes might be observed in severe COVID-19.

[Clinical analysis of early damage in multiple extra-pulmonary organs in COVID-19].

OBJECTIVE: To analyze the clinical manifestations of heart, liver and kidney damages in the early stage of COVID-19 to identify the indicators for these damages. METHODS: We analyzed the clinical features, underlying diseases, and indicators of infection in 12 patients with COVID-19 on the second day after their admission to our hospital between January 20 and February 20, 2020.The data including CK-MB, aTnI, BNP, heart rate, changes in ECG, LVEF (%), left ventricular general longitudinal strain (GLS, measured by color Doppler ultrasound) were collected.The changes of liver function biochemical indicators were dynamically reviewed.BUN, UCR, eGFR, Ccr, and UACR and the levels of MA, A1M, IGU, and TRU were recorded. RESULTS: The 12 patients included 2 severe cases, 8 common type cases, and 2 mild cases.Four of the patients presented with sinus tachycardia, ECG changes and abnormal GLS in spite of normal aTNI and LVEF; 1 patient had abnormal CKMB and BNP.On the first and third days following admission, the patients had normal ALT, AST and GGT levels.On day 7, hepatic function damage occurred in the severe cases, manifested by elevated ALT and AST levels.Abnormalities of eGFR, Ccr and UACR occurred in 8, 5 and 5 of the patients, respectively.Abnormal elevations of MA, A1M, IGU and TRU in urine protein were observed in 4, 4, 5, and 2 of the patients, respectively. CONCLUSIONS: In patients with COVID-19, heart damage can be identified early by observing the GLS and new abnormalities on ECG in spite of normal aTNI and LVEF.Early liver injury is not obvious in these patients, but dynamic monitoring of the indicators of should be emplemented, especially in severe cases. In cases with normal CR and BUN, kidney damage can be detected early by calculating eGFR, Ccr and UACR and urine protein tests.

Biodegradation of Atrazine by Mixed Bacteria of Klebsiella variicola Strain FH-1 and Arthrobacter sp. NJ-1.

The purpose of this study is to enhance the biodegradability of atrazine with FH-1 and NJ-1 alone by selecting the mixing ratio, optimizing the culture medium and conditions. The results showed that FH-1 and NJ-1 have the best biodegradation effect on atrazine being mixed in a volume ratio of 3:2. In a single factor experiment, sucrose and NH4Cl provided carbon and nitrogen sources for the mixed bacteria. Subsequently, composition of fermentation medium was further optimized using Box-Behnken design of response surface methodology. Based on the results, growth of mixed bacteria and biodegradation of atrazine performed best effects with a biodegradation rate of 85.6% when sucrose and NH4Cl amounts were 35.30 g/L and 10.28 g/L. The optimal medium condition was 10% inoculum of mixed bacteria, with initial atrazine concentration of 50 mg/L, neutral or weakly alkaline pH value, 30°C. The biodegradation rate reached 97.4%, 11.8% higher than the unoptimized condition.

Characteristics of Renal Function in Patients Diagnosed With COVID-19: An Observational Study.

Objective: The aim of the study was to analyze the characteristics of renal function in patients diagnosed with COVID-19. Methods: In this retrospective, single-center study, we included all confirmed cases of COVID-19 in a tertiary hospital in Guangdong, China from January 20, 2020 to March 20, 2020. Blood and urine laboratory findings related to renal function were summarized, and the estimated glomerular filtration rate (eGFR) and endogenous creatinine clearance (Ccr) were also calculated to assess the renal function. Results: A total of 12 admitted hospital patients were diagnosed with COVID-19, included 3 severe cases, and 9 common cases. Serum creatinine (Scr) was not abnormally elevated in all of the patients, and blood urea nitrogen (BUN) was abnormally elevated in only 25.0% of the patients. However, compared with the recovery period, the patient's Scr and BUN increased significantly in peak of disease (p-scr = 0.002 & p-bun < 0.001). By observing the fluctuations in Scr and BUN from admission to recovery, it was found that the peak of Scr and BUN appeared within the first 14 day of the course of the disease. Urinary microprotein detection indicated that the abnormally elevated rates of urine microalbumin (UMA), α1-microglobulin (A1M), urine immunoglobulin-G (IGU), and urine transferring (TRU) standardized by urinary creatinine in peak of disease were 41.7, 41.7, 50.0, and 16.7%, respectively. The abnormal rates of the calculated eGFR and Ccr were 66.7 and 41.7%. Conclusion: Scr and BUN were generally increased during the course of COVID-19. Detection of urinary microproteins and application of multiple indicators assessment could be helpful for discovering abnormal renal function in patients with COVID-19. However, the evidence is limited due to the small sample size and observational nature. Additional studies, especially large prospective cohort studies, are required to confirm these findings.