天花粉蛋白的定点聚乙二醇修饰

用一种定点修饰天花粉蛋白（ｔｒｉｃｈｏｓａｎｔｈｉｎ,ＴＣＳ）的方法,将聚乙二醇（ＰＥＧ）偶联到预先选定的位点．利用ｎＴＣＳ无半胱氨酸（Ｃｙｓ）残基这一特点,通过定点突变将一个Ｃｙｓ残基引入ＴＣＳ以取代第７位的丝氨酸（Ｓｅｒ）残基．然后,与巯基反应的ＰＥＧ－ｍ ａｌｅｉｍ ｉｄｅ 即可偶联到新引入的Ｃｙｓ 残基上．经纯化得到均一的ＰＥＧ－ＴＣＳ复合物,在ＳＤＳ－ＰＡＧＥ上显示一条区带,表观分子量为３８ ｋＤ．复合物的体外致核糖体失活活性降低了６倍,但其体内引产活性与ｎＴＣＳ相同．定点ＰＥＧ修饰方法为改造ＴＣＳ提供了新途径．     

Creatinine-Modified Gold Nanoparticles for Highly Sensitive Colorimetric Sensing of Nitroguanidine Explosive

Plasmonics - We report a simple, facile, selective, and highly sensitive colorimetric sensor for nitroguanidine explosive. The colorimetric sensor utilizes the aggregation of creatinine-modified...     

植物病原菌在森林动态中的作用

植物病原菌作为森林生态系统的重要组成成分及调控因子之一,在森林动态中扮演着重要的角色。植物病原菌通过侵染过程导致寄主植物的幼苗及成熟个体死亡、成熟个体的种子量降低或不实,或造成植物个体或群落中不同物种不同程度的病害,影响它们之间的营养竞争,从而导致群落结构、物种及个体数量的变化。感染散布前、后的种子和土壤种子库中的种子,以及由种子萌发产生的幼苗,它们的存活率降低,进而影响森林中的种子散布、幼苗更新与增补格局。在天然林中,先锋树种比顶极树种对病原菌更敏感,群落演替的早期阶段对病原菌比较敏感。植物病原菌主要通过密度依赖机制造成森林树种不同的死亡格局,从而参与森林的动态过程。     

畜禽粪便中抗生素抗性基因的分布特征及消减技术研究进展

随着集约化畜禽养殖业的不断发展,兽用抗生素的长期使用导致畜禽粪便抗生素抗性基因污染日益严重,对生态环境和人类健康造成严重危害。如何有效消减畜禽粪便中的抗生素抗性基因成为当前研究热点。本文系统总结了畜禽粪便中抗生素抗性基因的产生途径、分布和影响因素,并阐述了好氧堆肥、厌氧消化及其强化工艺消减畜禽粪便抗生素抗性基因的研究进展,根据现有工艺研究存在的问题展望了今后的重点研究方向,为畜禽粪便中抗生素抗性基因的消减提供理论基础和技术支撑。     

Nutrient-sensitive protein O-GlcNAcylation shapes daily biological rhythms

O-linked-N-acetylglucosaminylation (O-GlcNAcylation) is a nutrient-sensitive protein modification that alters the structure and function of a wide range of proteins involved in diverse cellular processes. Similar to phosphorylation, another protein modification that targets serine and threonine residues, O-GlcNAcylation occupancy on cellular proteins exhibits daily rhythmicity and has been shown to play critical roles in regulating daily rhythms in biology by modifying circadian clock proteins and downstream effectors. We recently reported that daily rhythm in global O-GlcNAcylation observed in Drosophila tissues is regulated via the integration of circadian and metabolic signals. Significantly, mistimed feeding, which disrupts coordination of these signals, is sufficient to dampen daily O-GlcNAcylation rhythm and is predicted to negatively impact animal biological rhythms and health span. In this review, we provide an overview of published and potential mechanisms by which metabolic and circadian signals regulate hexosamine biosynthetic pathway metabolites and enzymes, as well as O-GlcNAc processing enzymes to shape daily O-GlcNAcylation rhythms. We also discuss the significance of functional interactions between O-GlcNAcylation and other post-translational modifications in regulating biological rhythms. Finally, we highlight organ/tissue-specific cellular processes and molecular pathways that could be modulated by rhythmic O-GlcNAcylation to regulate time-of-day-specific biology.     

乙型肝炎病毒DNA在患者血清及肝组织中存在状态的研究

对29例肝炎,1例尸检肝组织和血清中乙型肝炎病毒的DNA(HBV DNA)进行了研究,发现HBsAg( )/HBeAg( )患者中,有9/17(52.94％)血清HBV DNA阳性;HBsAg( )/抗-HBe( )患者中,2/6(33.33％)也为阳性。从30例肝组织中提取DNA经琼脂糖电泳,Southern吸印转移及分子杂交试验结果表明,27例HBV DNA阳性,全部有游离型HBV DNA。27例中有5例经用标记pBR322探针杂交排除非特异杂交带后,在高分子量区有HBV DNA特异的杂交带,提示有HBV DNA整合。     

Association between Single-Nucleotide Polymorphisms of the Tyrosine Kinase Receptor B (TrkB) and Post-Stroke Depression in China

Background

Polymorphisms of the brain-derived neurotrophic factor (BDNF) have been investigated as candidate genes for post-stroke depression (PSD), and its receptor, neurotrophic tyrosine kinase receptor B (TrkB), has been associated with depression. However, no further data have yet reported the association between PSD and polymorphisms in TrkB. This study aims to investigate whether a relationship exists between TrkB polymorphisms and PSD.

Methods

A total of 312 depression patients (PSD patients) and 472 non-depression patient controls (NPSD patients) were recruited. All patients were evaluated using the Hamilton Rating Scale for Depression (HAMD) to determine depression severity, and PSD patients were diagnosed in accordance with DSM-V criteria. Three single-nucleotide polymorphisms (SNPs), namely, rs1187323, rs1212171, and rs1778929, in the TrkB gene were genotyped by high-resolution melt analysis.

Results

The SNP rs1778929 was significantly more associated with incident PSD in participants with the TT genotype than in those with CC (OR 0.482, 95% CI: 0.313–0.744). In terms of rs1187323, stroke was significantly more associated with incident depression in participants with the AC genotype than in those with AA (OR 0.500, 95% CI: 0.368–0.680). The minor allele (T) of rs1778929 (P = 0.024, OR = 0.725, 95% CI = 0.590–0.890) and the minor allele (C) of rs1187323 (P = 0.000, OR = 0.598, 95% CI = 0.466–0.767) were found to be significantly associated with PSD. Neither genotype nor allele frequencies of rs1212171 showed statistically significant differences between PSD and NPSD patients.

Conclusions

The results suggest that rs1778929 and rs1187323 in the TrkB gene are significantly associated with post-stroke depression in the Chinese population. Further studies are necessary to confirm our findings.     

Effects of disturbance intensity on seasonal dynamics of alpine meadow soil seed banks on the Tibetan Plateau

Background and Aims

Information on soil seed bank processes is crucial for understanding vegetation dynamics. Despite the documented importance of soil seed banks in many ecosystems, their role is not fully understood in some sensitive habitats, such as the alpine meadows of the Tibetan Plateau.

Methods

We studied the seasonal dynamics of the germinable soil seed bank under four disturbance intensities in an alpine meadow on the Tibetan Plateau as well as seed size distribution relative to disturbance intensity. Composition of the seed bank was compared with that of the standing vegetation.

Results

Density of buried seeds increased with disturbance intensity, but species richness and species diversity decreased. Seed density and species richness of the seed bank varied seasonally in all layers (0–2, 2–7, 7–12 cm) and the whole (0–12 cm). The species composition of seed bank was not significantly influenced by season. There was no trend in seed size distribution as disturbance increased. Seasonal seed bank turnover rates increased with increase in disturbance. The result of the NMDS showed that species composition of seed bank and vegetation exhibited a fairly uniform pattern in each season.

Conclusions

Although as a whole the species composition of the vegetation and seed bank showed a relatively low degree of similarity in each season, similarity was highest in the most disturbed habitat. There was no alteration in species composition of seed bank regardless of disturbance intensity, but seed density decreased as disturbance increased. Disturbances in alpine plant communities might increase persistence of regeneration niches. Regeneration from the seed bank together with vegetative reproduction contributed to aboveground vegetation in highly disturbed habitats. Clonal species played an important role in regeneration of vegetation in slightly disturbed areas, where there was little contribution of ruderals from soil seed banks.     

Taurine Interaction with Neurotransmitter Receptors in the CNS: An Update

Taurine appears to have multiple functions in the brain participating both in volume regulation and neurotransmission. In the latter context it may exert its actions by serving as an agonist at receptors of the GABAergic and glycinergic neurotransmitter systems. Its interaction with GABA_A and GABA_B receptors as well as with glycine receptors is reviewed and the physiological relevance of such interactions is evaluated. The question as to whether local extracellular concentrations of taurine are likely to reach the threshold level for the pertinent receptor populations cannot presently be answered satisfactorily. Hence more sophisticated analytical methods are warranted in order to obtain a definite answer to this important question. Special issue dedicated to Dr. Simo S. Oja