Study on gene sensor based on primer extension

Based on the fact that the resonant frequency of a piezoelectric crystal is the function of its surface deposit, and that the primer extends after it hybridizes with the template, the primer extension gene sensor technique was developed. The prominent feature of the technique is that fast and sensitive frequency signals are used as the monitoring system of gene hybridization and primer strand extension. Results show that this technique may be used in homologous analysis of nucleic acid, trace DNA detection, and determining the integration of DNA. It may also be used for isolation of target gene, gene mutation analysis, and predicting the location of a gene in its genome.     

Studies on Biosynthesis on Biotin by Microorganisms

The accumulation of biotin-vitamers in the culture media of a large number of microorganisms (about 700 strains) was studied. The contents of the biotin-vitamers were quantitatively determined by microbiological assays with Lactobacillus arabinosus and Saccharomyces cerevisiae.

It was found that large amounts of biotin-vitamers were accumulated by various microorganisms such as Streptomyces, molds and bacteria, and that the yield of biotin-vitamers was enhanced by the addition of pimelic acid or azelaic acid to the media. It was also found that the main portion of the vitamers accumulated by many microorganisms did not support the growth of Lactobacillus arabinosus, while it did support that of Saccharomyces cerevisiae. The small amounts of true biotin were observed in the culture media of various Streptomyces and molds, but hardly in the culture media of bacteria.

The identification of biotin-vitamers accumulated by various microorganisms is described, and the distribution of the vitamers in microorganisms is also described.

The results presented in this paper show that the main component of the vitamers accumulated by many microorganisms is identified as desthiobiotin by anion exchange column chromatography, paper chromatography and chemical analysis. Small amounts of fraction B (unidentified vitamers) and Fraction D (biotin) were also detected in the culture media of various molds and Streptomyces. However, these fractions were not observed in the culture media of any bacteria tested.

It was also found that large amounts of an unknown biotin-vitamer was accumulated by various bacteria. The vitamer was avidin-uncombinable, and, from the paper electrophoretic studies, it was assumed that the vitamer might be an analogue of pelargonic acid.     

连作对大豆根部土壤微生物的影响研究

研究了正茬与连作大豆根际及非根际土壤微生物区系的变化。结果表明,细菌总数占绝对优势,连作低于正茬。放线菌数量总体变化幅度不大,真菌数量有显著变化,连作明显高于正茬。连作使土壤pH、含水率和微生物主要生理类群数量明显下降,土壤肥力降低。无论细菌、放线菌和真菌,正茬及连作大豆根际微生物数量明显高于非根际。     

Research on dead human bodies: African perspectives on moral status

A useful concept that can be invoked to resolve complex bioethical issues is that of moral status (or, human dignity). In this article, we apply this concept to dead human bodies in order to support our view that research on such bodies is permissible. Instead of drawing from salient Western theories of human dignity that account for it by appeals to autonomy or rationality, we will base our investigation on emerging conceptions in African theories of moral status as articulated by Thaddeus Metz and Munamato Chemhuru. Our conclusion is that neither of these theories of moral status, one secular, and the other religious, can accommodate the intuition that we have direct duties of respect towards such bodies because, in relation to Metz's conception, they lack the capacity to enter into social relationships while on Chemhuru's conception, dead bodies appear not to have any meaningful purpose within the hierarchy that captures the ontological systems that determine such status. Consequently, we argue that our analysis provides support for the use of unclaimed cadavers in training and research in medical institutions.     

Perspectives on hair evolution based on some comparative studies on vertebrate cornification

Hair evolution contributed to the biological success of mammals. Hair origin from synapsid scales is speculative and requires extensive modifications of the morphogenetic process transforming lens-shaped dermis of scales into small dermal papillae in hair. Hair evolution from glands is hypothetical but is supported from studies on the signaling control of hair vs. glandular morphogenesis. Based on immunocytochemical and comparative studies, it is hypothesized that the onion-like organization of hair derived from glandular pegs which central part produced lipids and some keratin. In a following stage, involucrin, trichohyalin, and keratins were produced in the central cells of the gland and formed a solid medulla surrounded by keratinocytes of the inner root sheath. The origin of this protohair was possibly related to increased concentration of beta-catenin and other signaling molecules in epithelial cells following the evolution of a dermal papilla. The latter activated the keratogenic genes, already utilized in cells of the claws, in concentric layers of cells of the glandular peg. Lipidogenic genes were depressed. As new genes evolved in the genome of synapsids, new circular layers of keratinocytes containing specialized hard keratins and keratin-associated proteins were formed around medullary cells. The new keratinocytes probably originated the cortex separating medulla from the external cells that became the inner root sheath. The hypothesis indicates that in a following stage, the medulla was obliterated or replaced by cortical cells while the external part of the cortex formed a cuticular surface due to the different growth rate with inner root sheath cells.     

Understanding 2D projections on mirrors and on windows

Representational art tries to capture a 3D world on a 2D surface, and artists often discuss this in relation to the projected image on window panes and mirrors. But are 2D projections on transparent surfaces useful to learn about projections in general? Most people are unaware of the 2D projected size of objects on the surface of mirrors. They also incorrectly expect that these projections always get smaller with distance of the target object from the mirror, and do not change with distance of the observer (when the target is stationary). In this paper we extend this result about surfaces of mirrors to surfaces of windows, and we confirm that the errors that people make are not specific to Western culture by replicating the study in China. In contrast to their errors about projections, people are more accurate at predicting how field of view will vary depending on distance of the observer from a mirror or window. To explain how this pattern of (false) beliefs can stem from experience we argue that people do not perceive projections on transparent surfaces.     

花粉对Raji肿瘤细胞株的抑制作用研究

花粉是一种完全营养食品。研究花粉对Ｒａｊｉ肿瘤细胞株的抑制作用,结果：（１）破壁花粉中游离氨基酸组成基本与１６４０培养基相似;（２）花粉水提取液对Ｒａｊｉ肿瘤细胞株有明显的抑制作用     

Experimental excursions on adaptive landscapes: density-dependent selection on egg size

Abstract. Theories of density-dependent natural selection suggest that intraspecific competition will favor juveniles of high competitive ability. Empirical evidence has been provided from laboratory selection experiments, but field studies are lacking due to the logistical difficulties of experimentally manipulating population densities in natural settings. Here, we present data from a decade-long experimental field study of side-blotched lizards, Uta stansburiana that overcomes these difficulties. We tested the hypothesis that density-dependent natural selection causes egg size to increase from early to late clutches in this and many other species. Using a novel combination of environmental manipulations of hatchling density and phenotypic manipulations of egg size, we demonstrate that the nature of selection on egg size changes dramatically in the absence of older competitors. The strength of selection on egg size among later-clutch hatchlings released in areas without competitors from early clutches became almost doubled in magnitude, compared to that among hatchlings released in the presence of older competitors. These experimental findings demonstrate density-dependent natural selection on egg size; however, they contradict the classical idea that egg size increases during the reproductive season because of competition between early and late hatchlings. The results indicate that competitive age or size asymmetries between early and late hatchlings can override within-cohort asymmetries due to egg size. We suggest that competition could be an important mediator of oscillating selection pressures in this and other systems. Finally, we discuss the utility of "double-level," simultaneous experimental manipulation of both phenotypic traits that are targets of selection (e.g., egg size) as well the environmental agents of selection (e.g., population density).     

基于营养视角的中国食物进口需求研究

基于2000-2016年中国食物进口数据,从营养视角考察了中国热量及主要供能营养素进口来源分布情况,并实证估计了中国各营养成分进口需求弹性。研究发现：美国、巴西、阿根廷和东盟是中国热量、蛋白质、脂肪和碳水化合物进口的主要来源地;从支出弹性来看,美国和阿根廷的热量及主要营养素的支出富有弹性;所有营养的自价格弹性都为负。交叉价格弹性结果表明,在中国热量进口市场,美国与巴西和东盟之间表现出显著的替代关系;在蛋白质和脂肪进口市场,美国与巴西之间均表现出显著的替代关系;在脂肪进口市场,东盟与巴西和阿根廷之间存在着显著的互补关系;在碳水化合物进口市场,美国与东盟之间存在较强的替代关系。     

A comment on Bobisud's paper on evolution of cannibalism

One of Bobisud's (1976) models for the evolution, of cannibalism is discussed. His analysis is criticised for not being based on the principle of individual selection. Assuming the operation of that principle, we show by simulating his model that cannibals may establish themselves in a noncannibal population. This will happen both in cases where Bobisud concluded cannibalism to be optimal and in cases where he concluded cannibalism not to be optimal.     

Novel paradigm on the effect of estrogen on bone

According to prevailing unitary model of involutional osteoporosis, female postmenopausal bone loss can be divided into two separate phases: the accelerated, transient phase, which is most distinct over the subsequent decade after the menopause and accounts for 20-30% of the cancellous bone loss and 5-10% of the cortical bone loss (type I osteoporosis), and the following gradual, continuous bone loss (type II osteoporosis). Estrogen deficiency is currently quite unanimously accepted as the primary cause of type I osteoporosis, as well as also a major determinant of type II osteoporosis, and quite plausibly, the quest to uncover the origin of type I (and II) osteoporosis has focused on the estrogen withdrawal-related skeletal changes at and around the menopause. However, given that the cyclical secretion of estrogen begins normally in early adolescence and continues over the entire fertile period (excluding the potential periods of pregnancy) until the eventual cessation of female reproductive capability, one could argue that this menopause-oriented approach is limited in scope. In this review, some classic findings of the pubertal effects of estrogen on female bones are presented, findings that were paramount to Fuller Albright when he first described the disease called postmenopausal osteoporosis in 1940, but studies/findings that have failed to attract the attention they deserve. When these findings are incorporated with the primary function of the axial skeleton and long bones, the locomotion, an alternative, novel explanation for the function of estrogen and accordingly, the origin of the accelerated phase of postmenopausal bone loss, is proposed: estrogen packs mechanically excess bone/mineral into the female skeleton at puberty, a bone stock that later serves as the origin of the type I postmenopausal osteoporosis.     

基于HP模型的蛋白质折叠问题的研究

基于蛋白质二维HP模型提出改进的遗传算法对真实蛋白质进行计算机折叠模拟。结果显示疏水能量函数最小值的蛋白质构象对应含疏水核心的稳定结构,疏水作用在蛋白质折叠中起主要作用。研究表明二维HP模型在蛋白质折叠研究中是可行的和有效的并为进一步揭示蛋白质折叠机理提供重要参考信息。     

L-精氨酸耐缺氧效应的研究

通过模拟缺氧环境,试验灌胃L-精氨酸溶液对小白鼠耐缺氧时间、呼吸率、血浆和脑组织中NO水平的影响。对比结果显示灌胃L-精氨酸组减压耐缺氧和常压耐缺氧时间比空白组明显延长;肺组织切片显示L-精氨酸组血管明显舒张,耐缺氧效果显著。     

中国蜘蛛抱蛋属植物DNA条形码研究

利用植物DNA条形码候选序列mat K、psb A-trn H、psb K-psb I和rbc L对蜘蛛抱蛋属(Aspidistra)植物的19种104批样品进行扩增和测序,并采用相似性搜索算法(BLAST)对各序列的鉴定效率进行评价,得出蜘蛛抱蛋属物种鉴定的最佳序列。结果显示,psb K-psb I的物种鉴定成功率为88.7%,在单一序列中成功率最高。通过多序列组合鉴定效率的比较,发现组合序列的鉴定成功率明显高于单一序列,其中mat K+(psb K-psb I)组合的鉴定成功率高达100%,基于该序列组合构建蜘蛛抱蛋属植物的系统发育树,结果显示同一物种的样品聚集度较好,多表现为单系。研究结果表明mat K+(psb K-psb I)序列组合可作为蜘蛛抱蛋植物种鉴定的最佳条形码序列。     

胶原及其促创面修复作用的研究

本文介绍了牛胶原和猪真皮胶原制备方法、生物学特点以及动物移植的初步效果。结果表明胶原制备简便易行 ,氨基酸含量丰富 ,动物移植胶原材料效果肯定。提示胶原是创伤修复材料的理想天然生物资源     

A physicochemical investigation on the effects of ozone on blood

Ozonation of either human whole blood or saline-washed erythrocytes causes considerable damage to the latter and this result has opened a controversy. With the benefit of hindsight, it appears logical that once erythrocytes are deprived of the potent antioxidants of plasma, they become very sensitive to the oxidant effects of ozone. The aim of the present work was to perform a physical–chemical evaluation of some critical parameters able to clarify this issue. We have ascertained that when whole blood is exposed to the appropriate ozone doses used in human therapy, no damage ensues while saline-washed erythrocytes undergo conspicuous haemolysis. The dogma that ozone is always toxic is incorrect because its reactivity below the concentration of 80 μg/mL can be controlled by the plasmatic antioxidant system.     

Life on Mars

Abstract

There is evidence that at one time Mars had liquid water habitats on its surface. Studies of microbial communities in cold and dry environments on the Earth provide a basis for discussion of the possible nature of any life that may have existed on Mars during that time. Of particular relevance are the cyanobacterial communities found in hypolithic and endolithic habitats in deserts. Microbial mats found under ice-covered lakes provide an additional possible Martian system. Results obtained from these field studies can be used to guide the search for fossil evidence of life on Mars. It is possible that in the future life will be reintroduced on Mars in an effort to restore that planet to habitable conditions. In this case the organisms under study as exemplars of past life may provide the hardy stock of pioneering Martian organisms. These first organisms must be followed by plants. The feasibility of reviving Mars will depend on the ability of plants to grow in an abundance of CO₂ but at extremely low pressures, temperatures, O₂, and N₂ levels. On Mars, biology was, and is, destiny.     

Eavesdropping on visual secrets

Private communication may benefit signalers by reducing the costs imposed by potential eavesdroppers such as parasites, predators, prey, or rivals. It is likely that private communication channels are influenced by the evolution of signalers, intended receivers, and potential eavesdroppers, but most studies only examine how private communication benefits signalers. Here, we address this shortcoming by examining visual private communication from a potential eavesdropper’s perspective. Specifically, we ask if a signaler would face fitness consequences if a potential eavesdropper could detect its signal more clearly. By integrating studies on private communication with those on the evolution of vision, we suggest that published studies find few taxon-based constraints that could keep potential eavesdroppers from detecting most hypothesized forms of visual private communication. However, we find that private signals may persist over evolutionary time if the benefits of detecting a particular signal do not outweigh the functional costs a potential eavesdropper would suffer from evolving the ability to detect it. We also suggest that all undetectable signals are not necessarily private signals: potential eavesdroppers may not benefit from detecting a signal if it co-occurs with signals in other more detectable sensory modalities. In future work, we suggest that researchers consider how the evolution of potential eavesdroppers’ sensory systems influences private communication. Specifically, we suggest that examining the fitness correlates and evolution of potential eavesdroppers can help (1) determine the likelihood that private communication channels are stable over evolutionary time, and (2) demonstrate that undetectable signals are private signals by showing that signalers benefit from a reduction in detection by potential eavesdroppers.     

基于Meta分析研究芪明颗粒治疗糖尿病视网膜病变效果

用Meta分析方法比较中药复方芪明颗粒与羟苯磺酸钙两种药物治疗糖尿病视网膜病变的临床疗效和安全性。本研究利用中国期刊全文数据库(CNKI)、万方数据库、维普网、PubMed及Embase数据库检索芪明颗粒与羟苯磺酸钙治疗糖尿病视网膜病变的相关文献,检索时限均为建库至2016年5月31日,同时查阅该文献的参考文献。制定检索策略以及纳入和排除文献的标准,根据标准确定最终纳入的随机对照试验(RCT)文献。采用RevMan 5.2进行Meta分析,用固定效应模型进行数据合并。研究结果表明,共纳入文献8篇,均为RCT,涉及患者1 261名。纳入的研究方法学质量评价结果部分偏低。Meta分析结果显示:总有效率8项研究的同质性结果为卡方Ch^i2=5.98,自由度是7 (p=0.54),8项研究统计量均为二分类变量,故采取Z检验;M-H=1.96,95%可信区间为(1.52, 2.54),合并效应检验Z=5.13,p<0.001,表明芪明颗粒治疗组的总有效率大于对照组,两组比较差异具有统计学意义。不良反应发生率分析4项研究的同质性结果为卡方Ch^i2=0.41,自由度是3 (p=0.94),同属二分类变量,采取Z检验,M-H=0.15,95%可信区间为(0.05, 0.39),合并效应检验Z=3.82,p<0.001,表明芪明颗粒治疗组的不良反应发生率小于对照组,两组比较差异具有统计学意义。Meta分析初步表明,芪明颗粒治疗糖尿病视网膜病变疗效显著,安全性好。因不良反应原始研究的质量偏低,样本量小,尚需更多高质量、大样本的随机对照试验进一步观察研究。     

Reconstructing migratory patterns of fish based on environmental influences on otolith chemistry

The analysis of elements in calcifiedstructures of fish (e.g., otoliths) todiscriminate among fish stocks and determineconnectivity between populations is becomingwidespread in fisheries research. Recently, theconcentrations of elements in otoliths arebeing analysed on finer scales that allow thedetermination of a continuous record of otolithchemistry over a fish's entire life history.These elemental concentrations can potentiallybe used to reconstruct migration patterns,based upon the influence that water chemistry,temperature, and salinity have on otolithchemistry. In doing so, assumptions are madeabout how environmental and biological factorsinfluence the concentration of elements in fishotoliths. However, there have been fewexperiments that have tested crucialassumptions regarding what influences elementaluptake and incorporation into fish otoliths.Specifically, knowledge regarding interactionsamong environmental variables, such as theambient concentration of elements in water,temperature, and salinity, and how they mayaffect otolith chemistry, is limited.Similarly, our understanding of the rate atwhich elements are incorporated into otolithsand the implications this may have forinterpretations is lacking. This reviewdiscusses methods of determining movement offish, the development of otolith research, andsome physiological aspects of otoliths (e.g.,pathways of elemental uptake). The types ofanalysis techniques that will lead to reliableand accurate migratory reconstructions areoutlined. The effects that have on otolith chemistry arereviewed with the specific aim of highlightingareas lacking environmentalvariables in experimental data. Theinfluences of the rate of elementalincorporation and ontogeny on otolith chemistryare also addressed. Finally, future researchdirections are suggested that will fill thegaps in our current knowledge of otolithchemistry. Hypotheses that need to be tested inorder to reconstruct the migratory histories offish are outlined, in a bid to clarify thedirection that research should take beforecomplex reconstructions are attempted.