大熊猫染色体晚复制带研究

以培养的大熊猫外周血淋巴细胞为实验材料,在细胞培养终止前４ｈ加入ＢｒｄＵ（终浓度为１０μｇ／ｍｌ培养基）,对复制的染色体ＤＮＡ进行ＢｒｄＵ标记。掺入ＢｒｄＵ的染色体经吖啶橙（０．０５％）处理、紫外光照射、Ｇｉｅｍｓａ染色后,可在染色体上获得清晰的复制带纹。根据众多分裂相所显示的不同复制带型,可初步确定大熊猫每一染色体独特的晚复制带纹。在雌性个体的两个Ｘ染色体中,一条Ｘ染色体复制明显落后于另一Ｘ染色体,尤其在迟复制Ｘ染色体长臂近着丝粒区显现出较宽的晚复制带纹。     

Fate of ousted male residents of one-male bisexual troops of Hanuman langurs (Presbytis entellus) at Jodhpur,Rajasthan, India

Little is known about the fate of adult male residents after they are ousted from bisexual one-male troops of Hanuman langurs (Presbytis entellus) in the course of adult male replacements. In a long term study at Jodhpur, Rajasthan, it was possible to reconstruct partial life histories of several ousted residents. One resident was killed during the male change. Ousted residents did not regain residency despite their continued invasions into bisexual troops. It is assumed that the males' chances to take over and to defend a troop are restricted to an age of 9–14 years, when the males are in prime physical condition. One male became solitary for some months while trying to regain residency of his old troop, before joining some “alien” males. As a rule, males are likely to rejoin their own male bands if they are ousted after short periods of residency. If the residency exceeds 3 months then the ongoing structural change in the former band may prevent their reintegration. However, in such cases, ousted residents which belonged to the same band may reunite and mingle with another male band which lacks prime males. Weaned sons may follow their fathers after ousting. In the case of numerous weaned offspring, fathers and sons may together form at least temporary new male bands.     

Different Patterns of Changes in the Dry Season Diameter at Breast Height of Dominant and Evergreen Tree Species in a Mature Subtropical Forest in South China

Information on changes in diameter at breast height （DBH） is important for net primary production （NPP） estimates, timing of forest inventory, and forest management. In the present study, patterns of DBH change were measured under field conditions during the dry season for three dominant and native tree species in a monsoon evergreen broad-leaved forest in the Dinghushan Biosphere Reserve. For each tree species, different patterns of DBH change were observed. In the case of the fast-growing tree species Castanopsis chinensis Hance, large diurnal fluctuations occur, with a peak DBH in the early morning （around 05：00 h） that decreases to a minimum by about 14：00 h. Both Schima superba Gardn. et Chemp and Cryptocarya chinensis （Hance） Hemsh exhibited less diurnal swelling and shrinkage. Diurnal fluctuations for these species were observed on a few occasions over the period of observation. Graphical comparisons and statistical analysis of changes in DBH with meteorological variables indicate that for different trees, the different changes in DBH observed responded to different meteorological variables. Large stem changes were found to occur for Ca. chinensis trees that were associated with variations in solar radiation. However, both S. superba and Cr. chinensis were found to be less sensitive to solar radiation. Changes in the DBH of these two species were found to be controlled mainly by soil temperature and soil moisture. During the later dry season, with a lower soil temperature and soil moisture, all three tree species stopped growing and only negligible shrinkage, expansion, or fluctuation occurred, suggesting that the optimum time to measure tree growth in the Dinghushan Biosphere Reserve is the later dry season.     

Evaluation of genus <Emphasis Type="Italic">Cenchrus</Emphasis> based on malondialdehyde,proline content,specific leaf area and carbon isotope discrimination for drought tolerance and divergence of species at DNA level

Cenchrus (family Poaceae) is an important component of major grass covers of the world. Largely it is apomictic and both annual and perennial species exist in nature. Variations in contents of malondialdehyde, proline, specific leaf area and carbon isotope discrimination for drought tolerance were estimated among eight prominent species of Cenchrus. Simultaneously, genetic variations were also estimated by employing 187 RAPD primers. Of these, 23 primers did not react, 2 performed poorly and 7 produced many non-scorable bands and one primer yielded a single monomorphic band. Rest of the 154 primers generated one or more unambiguously scorable fragments. Twelve hundred and four of the 1,296 putative loci were polymorphic (93%) between at least one pair-wise comparisons among eight species. Dice coefficient and neighbor-joining algorithm analyses showed clustering patterns that fit with the known habitat of the species except perennial, C. myosuroides which formed a node between two annuals species. When these species were subjected to water stress tolerance test, a correlation (r = 0.612) between specific leaf area (SLA) and carbon isotope discrimination (CID) and difference in levels of drought tolerance based parameters among eight species were observed. Of the eight species investigated two annuals viz., C. biflorus and C. echinatus showed highest level of genetic similarity which was also evident from the similar levels of SLA, MDA, proline contents and carbon isotope discrimination values observed in these two species.     

Correlation between Raman and X-ray crystallography data of (Pro-Pro-Gly)10

Model biopolymers are powerful tools to guide the interpretation of physical properties in complex systems. (Pro-Pro-Gly)(10), (PPG)(10), is a collagen-model peptide, whose structure is known at high resolution. Herein, Raman microscopy data of (PPG)(10) powders and single crystals are reported. The spectra interpretation leads to an accurate assignment of three well-resolved amide bands corresponding to the three peptide bonds (PP, PG and GP) present in the (PPG)(10) structure. These data together with the availability of torsional angles phi and psi derived from the high-resolution crystal structure, provide the opportunity to test the validity of theoretical equations for the calculation of non-canonical amide III bands and represent a reference for theoretical calculations of vibrational spectra and for polyproline II detection in complex proteins. Spectroscopic data do not support the indication of two distinct and equally populated up and down conformations of the pyrrolidine rings observed in the (PPG)(10) crystal structure.     

Growth and Differentiation of Root Endodermis in Primula acaulis Jacq.

Adventitious roots of Primula acaulis Jacq. are characterized by broad cortex and narrow stele during the primary development. Secondary thickening of roots occurs through limited cambial growth together with secondary dilatation growth of the persisting cortex. Close to the root tip, at a distance of ca. 4 mm from the apex, Casparian bands (state I of endodermal development) within endodermal cells develop synchronously. During late, asynchronous deposition of suberin lamellae (state II of endodermal development), a positional effect is clearly expressed - suberization starts in the cells opposite to the phloem sectors of the vascular cylinder at a distance of 30 – 40 mm from the root tip. The formation of secondary walls in endodermis (state III of endodermal development) correlates with the beginning of secondary growth of the root at a distance of ca. 60 mm. Endodermis is the only cortical layer of primrose, where not only cell enlargement but also renewed cell division participate in the secondary dilatation growth. The original endodermal cells additionally divide anticlinally only once. Newly-formed radial walls acquire a typical endodermal character by forming Casparian bands and deposition of suberin lamellae. A network of endodermal Casparian bands of equal density develops during the root thickening by the tangential expansion of cells and by the formation of new radial walls with characteristic wall modifications. These data are important since little attention has been paid up till now to the density of endodermal network as a generally significant structural and functional trait of the root. This revised version was published online in July 2006 with corrections to the Cover Date.     

Heterochromatin and cytogenetic polymorphisms in Cebus apella (Cebidae,Platyrrhini)

Cytogenetic studies have been carried out in 39 specimens of C. apella of different origins. Three different morphologies, one affecting the long arm of chromosome 4 and two affecting pair 17, have been detected. In each case, they can be related by paracentric inversions. Heterochromatin polymorphisms affecting terminal or interstitial C+ regions have also been observed. The length of the terminal heterochromatic region in the long arms of chromosome 11 is variable in C. apella sp., in C. a. paraguayanus and absent in the C. a. nigritus specimens studied. Interstitial C + bands can be observed in the long arms of the biarmed chromosomes 4 and 6, and in the long arms of the acrocentric pairs 12, 13, 17, 18, 19, 20, and 21. Interstitial C + bands in the long arms of chromosomes 4, 12, 17, and 19 are present in all animals studied, although their size is variable, especially in the case of chromosomes 17 and 19. © 1995 Wiley-Liss, Inc.     

Combining Information from Similar Experiments: II. Quantifying Qualitative Results

Suppose that independent experiments each indicate general qualitative results, such as higher than normal incidence rates of tumors for exposed populations. This paper suggests methods for amalgamating the qualitative results from several such experiments into a more quantitative form, such as a dose-response relationship. The methods are designed to be robust both to systematic bias in one of the experiments and also to procedural variability across experiments. Data from four rodent experiments with tolazamide are used to illustrate the methods.     

Continued use of soft‐metal bands on gulls in North America reduces the value of recovery data

Use of soft‐metal (aluminum alloy) bands on gulls (Laridae) is known to result in high rates of band loss and, as a result, hard‐metal (monel, incoloy, or stainless steel) bands are superior for most studies. However, the U.S. Bird Banding Laboratory (BBL) and the Canadian Wildlife Service Bird Banding Office continue to issue soft bands for use on gulls, and the BBL does not make specific recommendations about use of hard bands so many banders continue to use soft bands. For wholly marine species of gulls banded in North America since 1996, ～20% have been banded with soft bands; the proportion of soft bands used on partially freshwater gulls was ～70% up to 2009, but has since fallen to 40%. Using hierarchical Bayesian models in program MARK, we analyzed recovery data for three gull species and found that estimates of annual survival rates derived from soft bands (0.68–0.81) were lower than those derived from hard bands (0.85–0.96). Comparison of survival rates of Herring Gulls (Larus argentatus) in the Great Lakes basin and on the Atlantic coast provided no evidence that soft bands last longer in freshwater than saltwater. Band loss compromises many types of studies, including those assessing the possible effects of climate change. We recommend that use of soft bands on gulls be discontinued, and that banders be required to use hard bands on these species in the future. The same consideration applies to other long‐lived species, including some waterfowl and all albatrosses, pelicans, cormorants, shearwaters, petrels, terns, shorebirds, and alcids. Use of hard bands should be based on expectations about a species’ longevity and evidence of band wear, rather than on whether or not it occurs in saltwater.