Azemiopsin from Azemiops feae viper venom, a novel polypeptide ligand of nicotinic acetylcholine receptor

Azemiopsin, a novel polypeptide, was isolated from the Azemiops feae viper venom by combination of gel filtration and reverse-phase HPLC. Its amino acid sequence (DNWWPKPPHQGPRPPRPRPKP) was determined by means of Edman degradation and mass spectrometry. It consists of 21 residues and, unlike similar venom isolates, does not contain cysteine residues. According to circular dichroism measurements, this peptide adopts a β-structure. Peptide synthesis was used to verify the determined sequence and to prepare peptide in sufficient amounts to study its biological activity. Azemiopsin efficiently competed with α-bungarotoxin for binding to Torpedo nicotinic acetylcholine receptor (nAChR) (IC(50) 0.18 ± 0.03 μm) and with lower efficiency to human α7 nAChR (IC(50) 22 ± 2 μm). It dose-dependently blocked acetylcholine-induced currents in Xenopus oocytes heterologously expressing human muscle-type nAChR and was more potent against the adult form (α1β1εδ) than the fetal form (α1β1γδ), EC(50) being 0.44 ± 0.1 μm and 1.56 ± 0.37 μm, respectively. The peptide had no effect on GABA(A) (α1β3γ2 or α2β3γ2) receptors at a concentration up to 100 μm or on 5-HT(3) receptors at a concentration up to 10 μm. Ala scanning showed that amino acid residues at positions 3-6, 8-11, and 13-14 are essential for binding to Torpedo nAChR. In biological activity azemiopsin resembles waglerin, a disulfide-containing peptide from the Tropidechis wagleri venom, shares with it a homologous C-terminal hexapeptide, but is the first natural toxin that blocks nAChRs and does not possess disulfide bridges.     

Comparison of nucleotide sequences of ribosomal DNA of the mosquito genera Aedes and Ochlerotatus (Diptera: Culicidae: Aedini)

Morphological study allowed identifying 9 species of mosquitoes of the genus Ochlerotatus and 2 species of the genus Aedes. Sequencing of the rDNA region was performed for all these speciemens. The sequences of rDNA were the following: A. cinereus -868 bp, A. vexans--889 bp, Och. cantans--803 bp, O. excrucians--801 bp, O. euedes--794 bp, Och. cyprius--777 bp, O. diantaeus--758 bp, O. intrudens--817 bp, Och. punctor--783 bp, O. dorsalis--748 bp, O. species--767 bp. On average, the size of Aedes rDNA fragments exceeds rDNA of Ochlerotatus by 90-100 bp. The sequences are characterized by a high number of insertions and deletions, and also by point substitutions of nucleotides. It is important to notice that interspecific differences include not only different regions of the internal transcribed spacers, but also the conservative site which is represented by the 5.8S gene. Among four substitutions in this gene, one (C/A) represents the difference between Aedes and Ochlerotatus, the next (T/A) distinguishes A. cinereus from Ochlerotatus speciment and A. vexans, and two substitutions (A/C, T/G) testify the similarity between O. dorsalis and O. species and specimens of Aedes. Besides, two more deletions are typical for O. dorsalis and O. species. One deletion is com- mon, it distinguishes them from the other examined species, and another one is typical only for O. dorsalis. When analyzing morphological characteristics and comparing nucleotide rDNA sequences of O. species with the database, the similarity to O. caspius has been revealed. On the whole, phylogenetic relationships among Ochlerotatus species correspond to subdivision into groups based on morphological characters. Probably, examination of the larger number of specimens will change the morphological division into groups.     

Cross-Sectional and Longitudinal Associations of Different Sedentary Behaviors with Cognitive Performance in Older Adults

Background

The deleterious health effects of sedentary behaviors, independent of physical activity, are increasingly being recognized. However, associations with cognitive performance are not known.

Purpose

To estimate the associations between different sedentary behaviors and cognitive performance in healthy older adults.

Methods

Computer use, time spent watching television (TV), time spent reading and habitual physical activity levels were self-reported twice (in 2001 and 2007) by participants in the SUpplémentation en Vitamines et MinérauX (SU.VI.MAX and SU.VI.MAX2) study. Cognitive performance was assessed at follow-up (in 2007–2009) via a battery of 6 neuropsychological tests used to derive verbal memory and executive functioning scores. Analyses (ANCOVA) were performed among 1425 men and 1154 women aged 65.6±4.5 at the time of the neuropsychological evaluation. We estimated mean differences with 95% confidence intervals (95%CI) in cognitive performance across categories of each type of sedentary behavior.

Results

In multivariable cross-sectional models, compared to non-users, participants using the computer for >1 h/day displayed better verbal memory (mean difference = 1.86; 95%CI: 0.95, 2.77) and executive functioning (mean difference = 2.15; 95%CI: 1.22, 3.08). A negative association was also observed between TV viewing and executive functioning. Additionally, participants who increased their computer use by more than 30 min between 2001 and 2007 showed better performance on both verbal memory (mean difference = 1.41; 95%CI: 0.55, 2.27) and executive functioning (mean difference = 1.41; 95%CI: 0.53, 2.28) compared to those who decreased their computer use during that period.

Conclusion

Specific sedentary behaviors are differentially associated with cognitive performance. In contrast to TV viewing, regular computer use may help maintain cognitive function during the aging process.

Clinical Trial Registration

clinicaltrial.gov (number {"type":"clinical-trial","attrs":{"text":"NCT00272428","term_id":"NCT00272428"}}NCT00272428).     

大苞藤黄化学成分研究及其互变异构体超高效液相色谱质谱联用分析

从大苞藤黄枝叶的混合粉碎物中分离到11个化合物,运用光谱手段分别鉴定为neobractatin(1),brasixanthone B (2),5-O-methylxanthone V1 (3),10-O-methylmacluraxanthone (4),isobractatin (5),xanthone V1(6),xerophenone A (7),xerophenone B (8),bractatin (9),macluraxanthone (10)和3-O-methylneobractatin (11).本文首次应用超高效液相色谱-质谱联用技术分离了异构体7和8并测定了其精确分子量.其中化合物6～8为首次从该植物中发现.     

无陪护老年病人住院期间护理需求的质性研究

目的:了解无陪护老年病人在住院期间的护理需求。方法:采用质性研究中现象学研究的半结构化、面对面、深度访谈方法采访11位内科无陪护老年病人,之后依据Claizzit的现象学资料7步分析法分析、整理资料。结果:无陪护老年病人住院期间的需求涉及病室、护理人员、陪护人员三方面。结论:无陪护老年病人住院期间有着其特殊需求,无陪护的原因主要有经济因素及陪护人员综合素质较低、无统一管理等,所以除了医院在护理工作中针对这类病人给予一些特殊照护外,呼吁政府建立规范的陪护人员培训及管理机构,为广大患者提供正规、专业化的陪护。     

Alcohol Consumption in Midlife and Cognitive Performance Assessed 13 Years Later in the SU.VI.MAX 2 Cohort

Background

Associations between alcohol consumption and cognitive function are discordant and data focusing on midlife exposure are scarce.

Objective

To estimate the association between midlife alcohol consumption and cognitive performance assessed 13 y later while accounting for comorbidities and diet.

Methods

3,088 French middle-aged adults included in the SU.VI.MAX (1994) study with available neuropsychological evaluation 13 y later. Data on alcohol consumption were obtained from repeated 24h dietary records collected in 1994–1996. Cognitive performance was assessed in 2007–2009 via a battery of 6 neuropsychological tests. A composite score was built as the mean of the standardized individual test scores (mean = 50, SD = 10). ANCOVA were performed to estimate mean differences in cognitive performance and 95% confidence intervals (CI).

Results

In women, abstainers displayed lower cognitive scores than did low-to-moderate alcohol drinkers (1 to 2 drinks/day) (mean difference = −1.77; 95% CI: −3.29, −0.25). In men, heavy drinkers (>3 drinks/day) had higher cognitive scores than did low-to-moderate (1 to 3 drinks/day) (mean difference = 1.05; 95% CI: 0.10, 1.99). However, a lower composite cognitive score was detected in male drinkers consuming ≥90 g/d (≈8 drinks/d). A higher proportion of alcohol intake from beer was also associated with lower cognitive scores. These associations remained significant after adjustment for diet, comorbidities and sociodemographic factors.

Conclusion

In men, heavy but not extreme drinking was associated with higher global cognitive scores. Given the known harmful effects of alcohol even in low doses regarding risk of cancer, the study does not provide a basis for modifying current public health messages.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00272428","term_id":"NCT00272428"}}NCT00272428     

Decreased collagen stability as a response to the loss of structural integrity of thyroid cartilage

The thermal behavior, birefringence properties, and the biochemical composition of thyroid cartilage tissues have been studied. The hyaline cartilage, which was visualized as a quasi-isotropic medium, was composed of type II collagen, which did not denature at temperatures up to 100 degrees C. However, in hyaline cartilage digested by trypsin, the denaturation of collagen occured at 60 degrees C. Collagen fibers in the perichondrium were composed of type I and II collagen and formed a highly organized anisotropic structure (birefringence about 4.75 x 10(-3)) with a melting temperature of about 65 degrees C. The temperature of collagen denaturation in perichondrium in the whole system perichondrium-hyaline cartilage increased up to 75 degrees C, indicating the immobilization of perichondrium collagen by the extracellular matrix of the hyaline constituent.     

蒜香藤叶挥发油的化学成分

蒜香藤（Pseudocalymma alliaceum Sandw．）又名紫铃藤,为紫葳科（Bignoniaceae）常绿藤状灌木,原产于南美洲的圭亚那和巴西。蒜香藤花、叶在搓揉之后,有浓浓的大蒜香味,其叶深绿富有光泽,花形大而优美,中国许多地方已引种栽培,一般作为篱笆、围墙美化或凉亭、棚架装饰之用。蒜香藤具有浓郁的蒜香,甚至可作为蒜的替代物用于烹饪。但有关其叶挥发性成分研究尚未见报道。本文利用气相色谱-质谱联用技术（GC—MS）分析了西双版纳植物园引种栽培的蒜香藤叶挥发油的化学成分,以期为合理开发和利用蒜香藤植物资源提供科学依据。     

甘薯愈伤组织中的淀粉酶

从甘薯愈伤组织和块根可溶性提取物中淀粉酶的非变性凝胶电泳和活性染色发现 ,愈伤组织和块根的淀粉酶完全不同。前者有 4种不同大小的淀粉酶 (2种α 淀粉酶和 2种 β 淀粉酶 ) ,而后者只有一种 (β 淀粉酶 ) ;其次 ,块根 β 淀粉酶对EDTA和 β 巯基乙醇都不敏感 ,而愈伤组织的淀粉酶对EDTA和 β 巯基乙醇都敏感。这些结果表明甘薯愈伤组织中不仅淀粉酶同工酶的数量多 ,而且包括α和 β两种类型。