Biodegradation kinetics of microcystins-LR crude extract by Lysinibacillus boronitolerans strain CQ5

As the most common variant of microcystins (MCs), microcystin-LR (MCLR) is a kind of toxins produced by some species of harmful cyanobacteria and more and more attention has been paid to it. Biodegradation has been extensively investigated and recognized to be a cost-efficient and environmentally benign method for MC clean-up. In order to further research the growth characteristics of strain and the biodegradation characteristics of MCLR, it is necessary to use the dynamic mathematical models as powerful and useful tools. In this study, strain CQ5 was screened and identified by morphological observation, physiological and biochemical tests, and 16S rDNA sequence analysis. The kinetic models of cell growth and MCLR degradation were established with the Gompertz model and revised Monod kinetic model. The results showed that strain CQ5 had the closest phylogenetic similarity to Lysinibacillus boronitolerans (T-10a, AB199591) in the phylogenetic tree, with 99% bootstrap support. Strain CQ5 could utilize MCLR as the carbon and nitrogen source for growth. When the initial pH value was 7 and the inoculation amount was 3%, strain CQ5 grew well in MSM, in which the MCLR crude extract was used as the carbon and nitrogen source of strain CQ5. Within 244 h, the MCLR concentration changed from 14.12 to 1.57 μg/L and its degradation rate could reach 88.88%. The growth curve fitted with the Gompertz growth model (Nt = 1.3119 * exp(−0.1237 * exp(−6.6341t)), R2 > 0.99). The process of MCLR degradation agreed with the first-order reaction kinetic equation (lnS = 2.64764 − 0.01537t, R2 > 0.99). The linkage relationship between MCLR concentration, cell density, and MCLR degradation rate was consistent with the revised Monod equation (V = 0.342S, R2 > 0.97) at low substrate concentration, where Vmax/ Ks was 0.342. The dynamic relationship in which strain CQ5 degraded MCLR and used it as the carbon and nitrogen source to promote its own growth could be explained by the equation S = 14.12 e− 0.342 Nt (N = 1.08). The growth of strain CQ5 and MCLR concentration in degradation system could be simulated and predicted by the dynamic mathematical models in this study. And the predicted results were very consistent. These results could provide theoretical reference for studying the mechanism of MCLR biodegradation and promote the engineering application of strain CQ5.     

对应分析和去趋势分析在有蹄类取食模式研究中的应用

本研究将2009年1月和2010年1月小兴安岭大沾河湿地自然保护区二可河林场内驼鹿冬季食性作为原始数据,分别以对应分析（CA）、去趋势分析（DCA）,并将数据以样本为单位进行标准化后,再进行去趋势分析（DCA_std）3种排序方法,对驼鹿冬季取食模式进行了研究,后通过普鲁克分析,比较了不同排序方法对大型有蹄类取食模式研究的效果。结果表明,3种排序法的1轴和2轴均能涵盖绝大多数信息量,CA涵盖79.27%,DCA涵盖66.65%,DCA_std涵盖68.22%;3种方法均能够在1轴上区分针叶树和落叶乔木类食物,在2轴上,3种方法主要能够达到针叶树种与除落叶乔木外的其他植物类别的区分。虽三者均能够展现有蹄类取食模式,但在图形可视化后,仅DCA_std无明显的弓形效应。普鲁克分析结果表明,DCA_std样本位移平方和与CA和DCA均有很大差异,即将数据先进行标准化再进行DCA分析能够有效去除弓形效应。因此,在由多度组成的食性数据在进行标准DCA分析前,应对数据进行前期处理会得到更好的效果。同时,以样本为单位的标准化将使排序分析结果生态学意义更明确。     

Structural characterization and bioactivity evaluation of an acidic proteoglycan extract from Ganoderma lucidum fruiting bodies for PTP1B inhibition and anti‐diabetes

A water‐soluble PTP1B inhibitor, named FYGL‐a, was fractionated for structure investigation and bioactivity evaluation. FYGL‐a is an ingredient of a reported antihyperglycemia extract from Ganoderma Lucidum fruiting bodies. Composition analysis indicated that FYGL‐a was a 100.2 kDa acidic proteoglycan, consisting of 85 ± 2% heteropolysaccharide chain with rhamnose, galactose, glucose, and glucuronic acid residues in a mole ratio of 1.0:3.7:3.9:2.0, and the 15 ± 2% protein moiety of FYGL‐a was covalently bonded to the polysaccharide chain in O‐linkage type via threonine residues. The complete sequence of FYGL‐a was characterized systematically by periodate oxidation, Smith degradation, methylation analysis, ¹H & ¹³C 1D NMR, and 2D NMR (HSQC, HMBC, NOESY, COSY, & TOCSY). The chemical structure of FYGL‐a was determined as following, which may play special role in the competitive inhibition of PTP1B and antihyperglycemia potency. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 613–623, 2014.

     

Conditional Deletion of Fgfr1 in the Proximal and Distal Tubule Identifies Distinct Roles in Phosphate and Calcium Transport

A postnatal role of fibroblast growth factor receptor-1 (FGFR1) in the kidney is suggested by its binding to α-Klotho to form an obligate receptor for the hormone fibroblast growth factor-23 (FGF-23). FGFR1 is expressed in both the proximal and distal renal tubular segments, but its tubular specific functions are unclear. In this study, we crossed Fgfr1^flox/flox mice with either gamma-glutamyltransferase-Cre (γGT-Cre) or kidney specific-Cre (Ksp-Cre) mice to selectively create proximal tubule (PT) and distal tubule (DT) Fgfr1 conditional knockout mice (designated Fgfr1^PT-cKO and Fgfr1^DT-cKO, respectively). Fgfr1^PT-cKO mice exhibited an increase in sodium-dependent phosphate co-transporter expression, hyperphosphatemia, and refractoriness to the phosphaturic actions of FGF-23, consistent with a direct role of FGFR1 in mediating the proximal tubular phosphate responses to FGF-23. In contrast, Fgfr1^DT-cKO mice unexpectedly developed hypercalciuria, secondary elevations of parathyroid hormone (PTH), hypophosphatemia and enhanced urinary phosphate excretion. Fgfr1^PT-cKO mice also developed a curly tail/spina bifida-like skeletal phenotype, whereas Fgfr1^DT-cKO mice developed renal tubular micro-calcifications and reductions in cortical bone thickness. Thus, FGFR1 has dual functions to directly regulate proximal and distal tubule phosphate and calcium reabsorption, indicating a physiological role of FGFR1 signaling in both phosphate and calcium homeostasis.     

Molecular characterization, polymorphism of bovine ZBTB38 gene and association with body measurement traits in native Chinese cattle breeds

Zinc finger and BTB domain containing 38 (ZBTB38), binding to and repressing methylated DNA, is an important candidate gene for selection of body measurement traits through marker-assisted selection (MAS). The expression of ZBTB38 is regulated in human and animal height as well as other stature indexes. Genomic structural analysis shows that bovine ZBTB38 shares much similarity with human ZBTB38. We discovered and evaluated the potential association of the single nucleotide polymorphism (SNP) of the bovine ZBTB38 gene with body measurement traits in 722 individuals. The latest findings demonstrate that the A841G SNP in exon 1 is significantly associated with Body Length (BL), Hip Height (HH) and Heart Girth (HG). Furthermore, the analysis of A841G SNP marker shows that there are significant effects on the BL (P = 0.0389) in 722 individuals, significant effects on the HH (P = 0.0173) and HG (P = 0.0147) in Qinchuan improvement steers (QI) population, as well as significant effects on the WH (P = 0.0094) in Xuelong (XL) population. These results clearly suggest that the ZBTB38 gene is among of target genes for body measurement traits in bovine reproduction and breeding, and thus provide data for establishment of an animal model using cattle to study big animal body type.     

泽陆蛙和饰纹姬蛙蝌蚪不同热驯化下选择体温和热耐受性

用泽陆蛙（Fejervarya limnocharis）蝌蚪和饰纹姬蛙（Microhyla ornata）蝌蚪做研究模型,检测热驯化（20 、25 和30 C）对选择体温（Tsel）、低温耐受性（CTMin）和高温耐受性（CTMax）的影响。结果显示,两种蝌蚪的Tsel既不受驯化温度的影响,也不存在种间差异;泽陆蛙蝌蚪的CTMin显著小于饰纹姬蛙蝌蚪,而CTMax和VTR则显著大于饰纹姬蛙蝌蚪;CTMin和CTMax随驯化温度的升高而升高,VTR则随驯化温度的升高而减小。研究结果表明,热驯化显著影响两种蝌蚪的CTMin、CTMax和VTR,而对两种蝌蚪的体温调定点无显著影响;这些热生物学特征对两种蝌蚪有效适应环境温度变化、利用资源、减少种间竞争具有重要的生态学意义。     

Sequential spiking neural P systems with exhaustive use of rules

Spiking neural P systems (SN P systems, for short) are a class of distributed parallel computing devices inspired from the way neurons communicate by means of spikes, where neurons work in parallel in the sense that each neuron that can fire should fire, but the work in each neuron is sequential in the sense that at most one rule can be applied at each computation step. In this work, we consider SN P systems with the restriction that at most one neuron can fire at each step, and each neuron works in an exhaustive manner (a kind of local parallelism - an applicable rule in a neuron is used as many times as possible). Such SN P systems are called sequential SN P systems with exhaustive use of rules. The computation power of sequential SN P systems with exhaustive use of rules is investigated. Specifically, characterizations of Turing computability and of semilinear sets of numbers are obtained, as well as a strict superclass of semilinear sets is generated. The results show that the computation power of sequential SN P systems with exhaustive use of rules is closely related with the types of spiking rules in neurons.     

黑龙江省老爷岭南部穆棱林区马鹿种群分布数量及生境适宜性评价

开展野生动物种群分布数量和生境适宜性评价研究是制定物种科学保护决策的基础和关键。以东北马鹿(Cervus canadensis xanthopygus)为研究对象,于2015—2020年在黑龙江省老爷岭南部穆棱林区,采用大样方调查方法收集马鹿在雪地留下的足迹信息分析马鹿种群数量;通过相机监测、足迹链跟踪和大样方调查3种方法综合收集马鹿活动点信息,利用最大熵(MaxEnt)建模分析马鹿生境适宜性。马鹿种群分布数量研究结果表明,穆棱林区马鹿种群密度为(0.0645±0.009)只/km~2,种群数量为47—61只,主要分布在研究地区南部的和平、龙爪沟和共和林场。生境分析结果表明：人为干扰因子中,居民区对MaxEnt模型的贡献率为44%,马鹿主要在距居民区距离约5 km和10—15 km的区域活动,在偏僻的林间小道和乡村道路马鹿生境适宜性较高,其对模型贡献率分别为16.8%和10.2%;植被因子中,在距常绿针叶林和针阔混交林距离4 km范围内,随距离增加马鹿生境适宜性逐渐降低。生境适宜性分析结果表明,研究地区马鹿适宜生境和次适宜生境面积为87.09 km~2,仅占研究区域的10.39%,主要...     

mmBCFA C17iso ensures endoplasmic reticulum integrity for lipid droplet growth

In eukaryote cells, lipid droplets (LDs) are key intracellular organelles that dynamically regulate cellular energy homeostasis. LDs originate from the ER and continuously contact the ER during their growth. How the ER affects LD growth is largely unknown. Here, we show that RNAi knockdown of acs-1, encoding an acyl-CoA synthetase required for the biosynthesis of monomethyl branched-chain fatty acids C15iso and C17iso, remarkably prevented LD growth in Caenorhabditis elegans. Dietary C17iso, or complex lipids with C17iso including phosphatidylcholine, phosphatidylethanolamine, and triacylglycerol, could fully restore the LD growth in the acs-1RNAi worms. Mechanistically, C17iso may incorporate into phospholipids to ensure the membrane integrity of the ER so as to maintain the function of ER-resident enzymes such as SCD/stearoyl-CoA desaturase and DGAT2/diacylglycerol acyltransferase for appropriate lipid synthesis and LD growth. Collectively, our work uncovers a unique fatty acid, C17iso, as the side chain of phospholipids for determining the ER homeostasis for LD growth in an intact organism, C. elegans.