Inertia in an ombrotrophic bog ecosystem in response to 9 years' realistic perturbation by wet deposition of nitrogen,separated by form

Wet deposition of nitrogen (N) occurs in oxidized (nitrate) and reduced (ammonium) forms. Whether one form drives vegetation change more than the other is widely debated, as field evidence has been lacking. We are manipulating N form in wet deposition to an ombrotrophic bog, Whim (Scottish Borders), and here report nine years of results. Ammonium and nitrate were provided in rainwater spray as NH₄Cl or NaNO₃ at 8, 24 or 56 kg N ha^?1 yr^?1, plus a rainwater only control, via an automated system coupled to site meteorology. Detrimental N effects were observed in sensitive nonvascular plant species, with higher cumulative N loads leading to more damage at lower annual doses. Cover responses to N addition, both in relation to form and dose, were species specific and mostly dependent on N dose. Some species were generally indifferent to N form and dose, while others were dose sensitive. Calluna vulgaris showed a preference for higher N doses as ammonium N and Hypnum jutlandicum for nitrate N. However, after 9 years, the magnitude of change from wet deposited N on overall species cover is small, indicating only a slow decline in key species. Nitrogen treatment effects on soil N availability were likewise small and rarely correlated with species cover. Ammonium caused most N accumulation and damage to sensitive species at lower N loads, but toxic effects also occurred with nitrate. However, because different species respond differently to N form, setting of ecosystem level critical loads by N form is challenging. We recommend implementing the lowest value of the critical load range where communities include sensitive nonvascular plants and where ammonium dominates wet deposition chemistry. In the context of parallel assessment at the same site, N treatments for wet deposition showed overall much smaller effects than corresponding inputs of dry deposition as ammonia.     

The mammalian testicular capsule and its muscle elements

This study of the testicular capsule of rat, dog, cat and human has confirmed the presence of three layers, viz., the tunica vaginalis, the tunica albuginea proper and an innermost tunica vasculosa. Smooth muscle cells are present in the tunica albuginea of all four species and are more prominent at the posterior pole of the testis where the capsule merges with the mediastinum testis. In the rat and the dog, a few striated muscle fibers also are present. While the tunica albuginea is to be considered as a dense connective tissue, the arrangement of the collagen bundles and the presence of a relatively high content of elastic fibers probably permits changes in size of the testis following spontaneous contractions of the muscle elements, which are known to occur. The role of the testicular capsule in sperm transport is discussed in relation to other factors, the spontaneous contractions of the capsule presumably having a “pumping” action and aiding the movement of non-motile spermatozoa from the testis to the epididymis. The presence of striated muscle fibers in two species is of interest and, while these may function in a similar manner to the smooth muscle, they may represent simply an unusual differentiation of embryonic myoblasts.     

A radiation hybrid map for the bovine Y Chromosome

Screening a bovine Y Chromosome-specific DNA library resulted in 34 new microsatellites, six of which mapped to the pseudoautosomal region (PAR), and 28 localized to the Y-specific region. These microsatellites, together with 23 markers previously mapped to the bovine Y Chr, were scored on a 7000-rad cattle–hamster radiation hybrid (RH) panel. Retention frequency of individual markers ranged from 18.5% to 76.5% with an average of 48.4%. Markers with high retention frequency (>55%) were found to exist in multiple copies on the Y Chr. Thirteen markers were placed on the PAR RH map with the AmelY gene proximal to the pseudoautosomal boundary and 46 markers, including Sry and Tspy gene, on the Y-specific region of the RH map. The microsatellites developed and mapped in this work will be useful for comparative mapping of cattle, sheep, and goat, studying the origin, evolution, and migration of bovidae species and provide an initial platform to develop a high-resolution map of the Y Chr and positional cloning of Y-specific genes.     

Interval mapping of growth in divergent swine cross

A genomic scan of 18 swine autosomal chromosomes was constructed with 119 polymorphic microsatellite (ms) markers to identify quantitative trait loci (QTL) for 11 growth traits in the University of Illinois Meishan × Yorkshire Swine Resource Family. A significant QTL effect was found for post-weaning average daily gain (ADG) between 5.5 and 56 kg of body weight that mapped between markers SW373 and SW1301 near the telomere of Chromosome (Chr) 1 q (SSC1). This QTL effect had a nominal (pointwise) p-value of 0.000007, a genome wide p-value of 0.012, and accounted for 26% of the F₂ phenotypic variance. The same chromosome region also had significant effects on ADG between birth and 56 kg body weight (p-value = .000227), and on ADG between 35 and 56 kg (p-value = .00077). These observations suggest that a significant QTL for post-weaning growth resides on SSC1. Received: 18 May 1998 / Accepted: 6 October 1998     

Development of the external muscle coats in the digestive tract of the opossum, Didelphis virginiana

Development of the external musculature of the gastrointestinal tract has been studied in the stomach, small intestine and colon of the postnatal opossum. The muscle support is thin and poorly developed at birth, especially in the stomach and small intestine where only the inner layer is completely formed. The outer layer is discontinuous and formed by scattered myoblasts. The muscularis externa of the colon at birth is considerably thicker and both layers are present. Subsequent development of the muscularis externa consists of an early period of proliferative activity followed by hypertrophy. A low rate of mitotic activity continues throughout development and into the adult. Elements of the myenteric plexus are present at birth.     

Utilization of processed pig hair in poultry diets

A commerically prepared sample of pig hair was evaluated in semi-purified and practical diets as a source of essential amino acids for poultry. Amino acid (total) supplementation of pig-hair protein in semi-purified diets indicated that the amino acids were utilized by poultry and that satisfactory performance was obtained when the protein was supplemented with the essential amino acids that analysis had shown to be lacking. The performance of broiler chickens fed on diets containing up to 6% pig hair, and of growing pullets fed on diets containing up to 9% of this material, suggests that properly processed pig hair can be used in rations along with other keratin proteins.     

Transcriptome Analysis Reveals Regulation of Gene Expression for Lipid Catabolism in Young Broilers by Butyrate Glycerides

ConclusionsOur results demonstrate that BG reduces body fat deposition via regulation of gene expression, which is involved in the biological events relating to the reduction of synthesis, storage, transportation and secretion, and improvement of oxidation of lipids and fatty acids.     

黄檗丛枝菌根真菌鉴定

目的：利用形态学特征与Nested-PCR技术鉴定黄檗丛枝菌根真菌。方法：采用酸性品红染色法挑选黄檗丛枝菌根。同时,利用湿筛法获得AM真菌孢子,进行形态学鉴定。运用Nested-PCR技术,对黄檗粗提DNA进行特异性扩增,采用blastn进行序列相似性比较。并构建系统进化树,确定侵染黄檗根系的AM真菌。结果：编号为HDAM-1的AM真菌孢子,形态特征与G．intraradices的特征描述一致。Nested-PCR检测到约455bp的目的片段,其序列与G．intraradices（DQ469118）相似性最高,达97．8％,有11个碱基的差异。系统进化树显示该序列在基于25S rDNA的进化树中与G．intraradices（DQ469118．1）处于同一分支,确定G．intraradices侵染黄檗根系。结论：将形态学特征与Nested-PCR技术相结合鉴定AM真菌,不仅简易、经济,而且能够提高研究结果的可靠性。     

From ATP to AZD6140: the discovery of an orally active reversible P2Y12 receptor antagonist for the prevention of thrombosis

Starting from adenosine triphosphate (ATP), the identification of a novel series of P2Y(12) receptor antagonists and exploitation of their SAR is described. Modifications of the acidic side chain and the purine core and investigation of hydrophobic substituents led to a series of neutral molecules. The leading compound, 17 (AZD6140), is currently in a large phase III clinical trial for the treatment of acute coronary syndromes and prevention of thromboembolic clinical sequelae.