西藏小型兽类五新纪录

1 长吻鼩鼹 Uropsilus gracilis 采自怒江以西,紧邻缅甸的察隅县日东乡(东经98.10702.,北纬28.49247.,海拔3450 m)小河边针叶林下灌丛环境. 长吻鼩鼹属于鼩形目(Don E.Wilson and DeeAnn M.Reeder,2005),鼹科. 个体小,吻尖,吻由软骨形成,管状.体背自头前至尾基为淡棕褐色,腹面为深灰色;尾较长,尾上下一色,具鳞状环纹,尾尖具稀疏笔刷状长毛,突出于尾端;四足背淡棕色.     

西藏小型兽类二新纪录

2009年和2011年,笔者在西藏查瓦龙地区开展了小型兽类调查,采集的标本经鉴定包括克钦绒鼠Eothenomys cachinus和克氏田鼠Microtus clarkei,为西藏自治区新纪录。克钦绒鼠于1921年由英国大英博物馆馆长Thomas作为田鼠属Microtus的物种命名Microtus cachinus,模式标本产于缅甸北部克钦省和我国云南高黎贡山交界处,海拔2743m。多数学者认为高黎贡     

两种小型兽类在我国的新分布区

1998年8－9月和1999年8－9月在内蒙古阿拉善地区对啮齿类进行了调查,捕到内蒙古兽类两个新记录种：间颅鼠兔（Ochotona cansus)和肥尾心颅跳鼠（Salpingotus crassicauda),经鉴定在国内属新的分布区。     

Olfaction in Mammals

This paper centers on selected—and particularly, littlerecognized— problems in mammalian olfaction: (1) Withcertain exceptions the spacing of the external nares in mostmammals does not favor orientation in an odor gradient by simultaneouscomparisons of odor intensities (tropotaxis). (2) The mammaliannose is rich in both dynamic and static devices for conditioningand controlling the How of inspired air. (3) A well-developedvomeronasal organ is widely distributed but its function isobscure. (4) Nerve impulse traffic telemetered from the olfactorybulb of freely moving rats shows a varying pattern of discretebursts of units with each inspiration and more sustained discharges.(5) Olfaction in species showing adaptations for lite in water,air, and underground is reviewed. (6) Because of its rich olfactory-trigeminalinnervation the snout of pigs, moles, etc., may be consideredas a "chemotactile" organ.     

Hepatocystis in Formosan Mammals with a Description of a New Species*

SYNOPSIS. Hepatocystis has been found extremely common in a number of species of Formosan mammals, notably the large leafnosed bat (Hipposideros armiger terasensis), the Formosan macaque (Macaca cyclopis), and various subspecies of the red-bellied tree squirrel (Callosciurus erythraeus). Less often infected were the long-winged bat (Miniopterus schreibersii) and the Formosan giant flying squirrel (Petaurista grandis). The species occurring in H. a. terasensis is believed to be new, and is named Hepatocystis hipposideri. It causes considerable enlargement (but not other changes) of the host cell, is often amoeboid, and usually has numerous fine pigment granules.     

A New Methodology for Studying the Activity of Underground Mammals

Biology Bulletin - A new methodology for studying the activity of underground mammals with the use of a digital portable voice recorder has been elaborated. Previously, mole rats were visually...     

A New Noninvasive Method for Detecting Mammals From Birds' Nests

Abstract: Certain birds use mammal hair for the lining or structural strengthening of their nest. As a result, many bird nests can be regarded as natural hair snares. Preliminary studies indicate that analyses of hairs found in birds' nests are an effective method for detecting and identifying mammals that live in or migrate through an area and could be a useful tool to gain information about rare or hard to detect mammals. I documented 27 mammal taxa that were identified from hair collected from >3,000 nests. This study summarizes the results of 4 projects that represent application of this technique. This noninvasive method appears to be a useful tool for easily accessing basic faunistical data about mammal fauna of the given area.     

Genomic Imprinting in Mammals

A review of the data on the mechanisms and effects of genomic imprinting, an epigenetic phenomenon regulating the development in placentate mammals, is presented. In contrast to the majority of gene loci with biallelic expression, the expression of imprinted loci is monoallelic. In humans and mice, more than 30 imprinted loci have been identified, in which maternal or paternal alleles may either be expressed or be found in a repressed state during ontogeny. Imprinting is established during gametogenesis, and the repression of an allele of the imprinted locus is determined by methylation of the key regulatory element of this allele. Both the maternal and paternal chromosome sets are required for normal development in mammals. This is why parthenogenesis and androgenesis in these animals are impossible in nature. As a result of differential gene expression of many imprinted loci, the balance of gene activity is established, which is necessary for normal proliferation and differentiation of various cell clones in embryogenesis. Many human developmental abnormalities and syndromes are determined by defective genomic imprinting. In particular, the loss of imprints, which is followed by the occurrence of biallelic expression of some imprinted loci, may cause malignant tumors.     

Dosage Compensation in Mammals

Many organisms show major chromosomal differences between sexes. In mammals, females have two copies of a large, gene-rich chromosome, the X, whereas males have one X and a small, gene-poor Y. The imbalance in expression of several hundred genes is lethal if not dealt with by dosage compensation. The male–female difference is addressed by silencing of genes on one female X early in development. However, both males and females now have only one active X chromosome. This is compensated by twofold up-regulation of genes on the active X. This complex system continues to provide important insights into mechanisms of epigenetic regulation.     

DNA Methylation in Mammals

DNA methylation is one of the best characterized epigenetic modifications. In mammals it is involved in various biological processes including the silencing of transposable elements, regulation of gene expression, genomic imprinting, and X-chromosome inactivation. This article describes how DNA methylation serves as a cellular memory system and how it is dynamically regulated through the action of the DNA methyltransferase (DNMT) and ten eleven translocation (TET) enzymes. Its role in the regulation of gene expression, through its interplay with histone modifications, is also described, and its implication in human diseases discussed. The exciting areas of investigation that will likely become the focus of research in the coming years are outlined in the summary.     

Genomic Imprinting in Mammals

Genomic imprinting affects a subset of genes in mammals and results in a monoallelic, parental-specific expression pattern. Most of these genes are located in clusters that are regulated through the use of insulators or long noncoding RNAs (lncRNAs). To distinguish the parental alleles, imprinted genes are epigenetically marked in gametes at imprinting control elements through the use of DNA methylation at the very least. Imprinted gene expression is subsequently conferred through lncRNAs, histone modifications, insulators, and higher-order chromatin structure. Such imprints are maintained after fertilization through these mechanisms despite extensive reprogramming of the mammalian genome. Genomic imprinting is an excellent model for understanding mammalian epigenetic regulation.     

哺乳动物嗅觉与母性识别

嗅觉通讯在陆生哺乳动物母性识别中具有重要作用。通过嗅觉信息,早熟性动物(有蹄类)产后早期能够迅速建立专一性的母性识别和母子联系,并具有母性识别的敏感期。在敏感期内,分娩经验、催产素及一氧化氮等神经递质的释放有助于这种识别和联系的形成。多项研究表明,晚熟性动物(如啮齿类)母性识别的形成主要基于断乳前母兽与幼仔共处获得的熟悉性,产后早期不能迅速形成专一性的母性识别和母子联系,母兽对亲生幼仔和非亲生幼仔的选择性哺育不完全取决于识别。实验方法及识别的判定标准对研究啮齿类的母性识别尤其重要。包括人类在内的灵长类母亲产后只通过嗅觉信息即可以对婴儿进行识别。在哺乳动物的母性识别中,妊娠和分娩过程会诱导嗅觉系统的高度可塑性,有利于促进母亲对幼体气味的学习,但硬连接(hard-wired)路径也可能参与母性识别。     

High Altitude Adaptation in Mammals

The physiological, morphological, and biochemical characteristicsof several species of mammals resident at high altitude arecompared with those of their sea level counterparts. The differencesnoted in these characteristics are in a direction that facilitatesthe acclimatization of those living at high altitude. The differencesamong species point to the fact that the mechanism of adaptationto altitude (i.e., hypoxia) is still not understood. This reviewemphasizes that the adaptive process is complex and made upof several components, that these components are inter-related,and that neither the physiological nor morphological adaptationscan fully account for the tolerance to hypoxia. Although onlysuperficially studied as yet, the biochemical adaptations appearmost important.