Expression of L3T4 molecules on Lyt-2+, class II-restricted antigen-specific T suppressor lymphocytes

Three bovine serum albumin-specific Lyt-2⁺ T suppressor (Ts) cell clones from CBA/J mice have been analyzed with regard to expression of L3T4 molecules. All three Ts-cell clones can be stained with monoclonal antibodies (mAb) to L3T4. Tested for the two clones restricted to recognition of E^k determinants, antigen-specific proliferation on antigen-presenting cells, but not the proliferation induced by conditioned medium can be inhibited by L314-specific mAb. In a similar way, Ts-cell cytolytic effector functions can be blocked by L3T4-specific mAb. Thus L3T4 structures seem to play a role in Ts-cell functions. Furthermore, the data support the view that L3T4 expression can be a property of class II-restricted T cells irrespective of their Lyt phenotype.     

Effects of T4 lysozyme release from transgenic potato roots on bacterial rhizosphere communities are negligible relative to natural factors

Rhizosphere bacterial communities of two transgenic potato lines which produce T4 lysozyme for protection against bacterial infections were analyzed in comparison to communities of wild-type plants and transgenic controls not harboring the lysozyme gene. Rhizosphere samples were taken from young, flowering, and senescent plants at two field sites in three consecutive years. The communities were characterized in a polyphasic approach. Cultivation-dependent methods included heterotrophic plate counts, determination of species composition and diversity based on fatty acid analysis of isolates, and community level catabolic profiling. Cultivation-independent analyses were based on denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments amplified from rhizosphere DNA using primers specific for Bacteria, Actinomycetales, or alpha- or beta-Proteobacteria. Several bands of the DGGE patterns were further characterized by sequence analysis. All methods revealed that environmental factors related to season, field site, or year but not to the T4 lysozyme expression of the transgenic plants influenced the rhizosphere communities. For one of the T4 lysozyme-producing cultivars, no deviation in the rhizosphere communities compared to the control lines was observed. For the other, differences were detected at some of the samplings between the rhizosphere community structure and those of one or all other cultivars which were not attributable to T4 lysozyme production but most likely to differences observed in the growth characteristics of this cultivar.     

Structure and developmental expression of the chicken NGF receptor

The nucleotide and deduced amino acid sequence of a cDNA clone of the chicken NGF receptor (NGFR) is reported and is compared with sequences of mammalian NGF receptors. A model is presented in which monodentate or bidentate binding of NGF dimers to repeated cysteine-rich sequence elements of the receptor yields low- or high-affinity NGF binding, respectively. In situ hybridization is used to characterize expression of NGFR in developing chick from 40 hr to 10 days of embryogenesis. NGFR mRNA expression is detected in premigratory neural crest cells, in epibranchial placode cells, and in all sensory, sympathetic and parasympathetic derivatives of these structures. In the embryonic CNS, NGFR mRNA is detected in the mantle zone but not the periventricular germinal zone throughout most of the neural tube. By Embryonic Day 8, NGFR mRNA is detected in a substantial fraction of cells in every brain region, with highest levels present in developing motor neurons. NGFR mRNA also is transiently expressed in many mesenchymal cell populations including cells in branchial arch, sclerotome, muscle anlagen, and feather follicles. The functional significance of wide-spread embryonic expression of the NGF receptor is discussed.     

我国恙虫蚴的三个新种(蜱螨目, 恙虫科)

近几年来,我国科学家们在恙虫方面的研究工作巳经取得了显著的成就。然而,这对于拥有辽阔疆土的我国来说,实在只不过是一个开始。我们在这方面的工作也做得很少,虽然从1953年开始收集标本,由于各种条件所限制,未能及时整理,以致大量标本散失或霉烂,十分可惜。本文内容,仅仅是将我站恙虫病调研工作组1957年在本省各地所采集的材料中的三种恙虫蚴加以描述,该三种恙虫蚴均系文献上未曾记载过的种类。     

Opposite fates of the purine metabolite allantoin under water and nitrogen limitations in bread wheat

Plant Molecular Biology - Degradation of nitrogen-rich purines is tightly and oppositely regulated under drought and low nitrogen supply in bread wheat. Allantoin is a key target metabolite for...     

心房钠尿因子对麻醉家兔局部血流的影响

在42只麻醉家兔,观察了静脉注射心房肽Ⅱ(AtriopeptinⅡ,APⅡ)对局部血流量以及动脉内注射 AP Ⅱ 对局部血管阻力的影响。结果如下:(1)静脉注射 APⅡ(30μg/kg)5min后,平均动脉压(MAP)降低11.0±1.5mmHg(n=8,M±SE,下同),与溶剂对照组相比有明显差异(P相似文献