Rock paper scissors: CRISPR/Cas9-mediated interference with geminiviruses in plants

<正>Geminiviruses are a group of circular single-stranded DNA viruses that constitute the largest family of plant viruses.Many diseases resulting from geminivirus infections, such as maize streak disease, cassava mosaic disease, tomato yellow leaf curl disease and cotton leaf curl diseases, cause significant problems in terms of economic losses, posing a serious threat to global crop productivity (Hanley-Bowdoin et al., 2013; Yang et al., 2019). As obligate intracellular     

A Novel Hyaluronidase Produced by Bacillus sp. A50

Hyaluronidases are a family of enzymes that degrade hyaluronic acid (hyaluronan, HA) and widely used in many fields. A hyaluronidase producing bacteria strain was screened from the air. 16S ribosomal DNA (16S rDNA) analysis indicated that the strain belonged to the genus Bacillus, and the strain was named as Bacillus sp. A50. This is the first report of a hyaluronidase from Bacillus, which yields unsaturated oligosaccharides as product like other microbial hyaluronate lyases. Under optimized conditions, the yield of hyaluronidase from Bacillus sp. A50 could reach up to 1.5×10⁴ U/mL, suggesting that strain A50 is a good producer of hyaluronidase. The hyaluronidase (HAase-B) was isolated and purified from the bacterial culture, with a specific activity of 1.02×10⁶ U/mg protein and a yield of 25.38%. The optimal temperature and pH of HAase-B were 44°C and pH 6.5, respectively. It was stable at pH 5–6 and at a temperature lower than 45°C. The enzymatic activity could be enhanced by Ca²⁺, Mg²⁺, or Ni²⁺, and inhibited by Zn²⁺, Cu²⁺, EDTA, ethylene glycol tetraacetic acid (EGTA), deferoxamine mesylate salt (DFO), triton X-100, Tween 80, or SDS at different levels. Kinetic measurements of HAase-B towards HA gave a Michaelis constant (K _m) of 0.02 mg/mL, and a maximum velocity (V _max) of 0.27 A ₂₃₂/min. HAase-B also showed activity towards chondroitin sulfate A (CSA) with the kinetic parameters, K _m and V _max, 12.30 mg/mL and 0.20 A ₂₃₂/min respectively. Meanwhile, according to the sequences of genomic DNA and HAase-B’s part peptides, a 3,324-bp gene encoding HAase-B was obtained.     

MicroRNA‐183‐5p is stress‐inducible and protects neurons against cell death in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the death of motor neurons. A fundamental pathogenesis of ALS is the prolonged cell stress in neurons, which is caused by either accumulation of protein aggregates or reactive oxygen species. However, the mechanistic link between stress sensing and cell death is unsettled. Here, we identify that miR‐183‐5p, a neuron‐enriched miRNA, couples stress sensing and cell death programming in ALS. miR‐183‐5p is immediately induced by hydrogen peroxide, tunicamycin or TNF‐α in neurons. The overexpression of miR‐183‐5p increases neuron survival under stress conditions, whereas its knockdown causes neuron death. miR‐183‐5p coordinates apoptosis and necroptosis pathways by directly targeting PDCD4 and RIPK3, and thus protects neurons against cell death under stress conditions. The consistent reduction of miR‐183‐5p in ALS patients and mouse models enhances the notion that miR‐183‐5p is a central regulator of motor neuron survival under stress conditions. Our study supplements current understanding of the mechanistic link between cell stress and death/survival, and provides novel targets for clinical interventions of ALS.     

Alkyl Polyglucoside (APG) Amendment for Improving the Phytoremediation of Pb-PAH Contaminated Soil by the AquaticPlant Scirpus triqueter

This study assessed the potential abilities of Scirpus triqueter for phytoremediation of soils contaminated with Pb-PAHs, amended with environment-friendly surfactant alkyl polyglucoside (APG). The effects of APG on the removal of PAHs from soil and the plant uptake and translocation of Pb were tested with plant growth and soil enzymatic activities. Experiments demonstrated that APG has an ability to facilitate PAH degradation and Pb uptake in the plant body at appropriate concentrations (20–40mg L^?1). The highest PAH removal rate was observed in 30 mg L^?1 APG treatment, and the highest accumulation of Pb was detected as 40 mg L^?1 APG. Experiments documented the effects of APG on plant growth, soil enzymatic activity, bioaccumulation and translocation of Pb in Scirpus triqueter. Results indicated that the addition of appropriate APG enhanced PAH removal rate and increased plant uptake and translocation of Pb.     

S‐nitrosylated protein disulfide isomerase contributes to mutant SOD1 aggregates in amyotrophic lateral sclerosis

A major hallmark of mutant superoxide dismutase (SOD1)‐linked familial amyotrophic lateral sclerosis is SOD1‐immunopositive inclusions found within motor neurons. The mechanism by which SOD1 becomes aggregated, however, remains unclear. In this study, we aimed to investigate the role of nitrosative stress and S‐nitrosylation of protein disulfide isomerase (PDI) in the formation of SOD1 aggregates. Our data show that with disease progression inducible nitric oxide synthase (iNOS) was up‐regulated, which generated high levels of nitric oxide (NO) and subsequently induced S‐nitrosylation of PDI in the spinal cord of mutant SOD1 transgenic mice. This was further confirmed by in vitro observation that treating SH‐SY5Y cells with NO donor S‐nitrosocysteine triggered a dose‐dependent formation of S‐nitrosylated PDI. When mutant SOD1 was over‐expressed in SH‐SY5Y cells, the iNOS expression was up‐regulated, and NO generation was consequently increased. Furthermore, both S‐nitrosylation of PDI and the formation of mutant SOD1 aggregates were detected in the cells expressing mutant SOD1^G93A. Blocking NO generation with the NOS inhibitor N‐nitro‐l ‐arginine attenuated the S‐nitrosylation of PDI and inhibited the formation of mutant SOD1 aggregates. We conclude that NO‐mediated S‐nitrosylation of PDI is a contributing factor to the accumulation of mutant SOD1 aggregates in amyotrophic lateral sclerosis.     

Prevalence,Awareness, Medication,Control, and Risk Factors Associated with Hypertension in Bai Ethnic Group in Rural China: The Yunnan Minority Eye Study

Purpose

This study aimed to assess the prevalence, awareness, treatment, and control of hypertension and their associated factors among Bai ethnic population in the rural China.

Methods

A population-based survey was conducted in 2010 with a randomly cluster sampling in rural communities in Dali, southwest China. A total of 2133 adults aged 50 or above were interviewed, and their blood pressure, height, weight and waist circumference were measured. Hypertension was defined as a mean SBP≥140 mmHg and/or DBP≥90 mmHg, and/or current use of antihypertensive medications.

Results

The prevalence of hypertension was 42.1% (899/2133), and the age- and gender-adjusted prevalence was 40.0%. Among the hypertensive participants, 28.4% (255/899)were aware of their condition, while 24.6% (221/899) took antihypertensive medications, with only 7.5% (67/899) of those achieving blood pressure control (<140/90 mmHg). Risk factors for hypertension were older age, smoking, alcohol drinking, family history of HBP, overweight, and obesity, while protective factors included being lean, and having finished senior high school or above.

Conclusions

Hypertension prevalence is high among the population of Bai ethnic group in China, while the associated risk factors of hypertension include overweight/obesity, cigarette smoking, history of hypertension, and older age. The percentages of hypertensive participants aware of their hypertension and those taking antihypertensive medications were low with an incredibly low proportion of hypertensive patients who kept their hypertension under control. It is suggested that health education and hypertension screening programs be carried out in the area for the high blood pressure prevention and control.     

Selection of optimal flocculant for effective harvesting of the fucoxanthin-rich marine microalga <Emphasis Type="Italic">Isochrysis galbana</Emphasis>

Flocculation harvesting of the fucoxanthin-rich marine microalga Isochrysis galbana has received little attention. Therefore, we attempted to screen for an optimal chemical flocculant and optimize flocculation conditions from five chemical flocculants—ferric chloride (FC), aluminum sulfate (AS), polyaluminum chloride (PAC), aluminum potassium sulfate (APS), and zinc sulfate (ZS)—for effective flocculation of I. galbana. The growth rate, photosynthetic performance, and fucoxanthin content were determined in re-suspended flocculated algal cells and in the flocculation supernatant cultured algal cells. The results showed that high growth rate and fucoxanthin accumulation were observed when FC was used as the flocculant in I. galbana cultures, which indicated that FC may cause less harm to I. galbana than the other aluminum-based flocculants. Furthermore, satisfactory flocculation efficiency was also observed when FC was used to flocculate I. galbana, and the FC dosage was less than that required for flocculation of I. galbana using PAC, APS, and AS. Thus, we selected FC as the optimal flocculant for harvesting I. galbana based on its flocculation efficiency together with algal physiological performance, growth rate, and fucoxanthin content.     

Polyphenols of Leaf,Litter and Soil of Pinus bungeana across China and Their Responses to Ecological Factors

The importance of phenolic compounds for responding to various environmental conditions has been widely emphasized. However, the role of interactions between polyphenols and ecological factors, especially C, N, and P stoichiometry was little studied. Here, 15 sites across five provinces of Pinus bungeana in temperate regions of China were studied. The results showed that the higher values of total phenolic contents (TPC) of leaf and litter were distributed among the north distribution area of P. bungeana, lower values were in the south, whereas soil TPC were contrary to leaf and litter TPC. The stepwise regression, path analysis and decision index of path analysis for leaf TPC and ecological factors showed that altitude had the most direct impact on leaf TPC. Moreover, the principal determinants of leaf, litter and soil TPC were soil C/P ratios, longitude, and soil N/P ratios, respectively. In addition, the leaf, litter and soil TPC of P. bungeana were limited by soil C/N ratios, mean annual temperature, and soil P, respectively. Overall, our study provided evidence that ecological factors affected strongly the leaf, litter and soil TPC of P. bungeana.