Ir gene influence on DNP-specific B-memory-cell formation

It is well known that Ir genes control the antibody production. To investigate whether they also influence B-memory-cell generation, CBA mice (nonresponders) were primed with dinitrophenyl-poly-(L-tyr,L-glu)-poly-(D,L-ala)-poly-(L-lys)-DNP-TGAL conjugate. At the same time animals were injected with ovalbumin (OVA) to activate OVA-specific T helpers. Two to four weeks later animals were challenged with DNP-OVA conjugate and the number of IgG-producing B cells was determined. The data presented indicate that carrier-specific MHC-restricted T helpers are not required for B-memory-cell generation. It is concluded that the defect of IgG response to DNP-TGAL in CBA mice is caused by a block in the maturation of memory cells to antibody-producing cells.     

俄罗斯北部平原(VYCHEGDA河盆地)全新世植物群和植被

对Vychegda河流域靠近Baika村(61°16'N,46°44'E)洪积平原的一个剖面进行了孢粉学研究.化石点位于泰加林带中部,靠近欧洲云杉林和亚乌拉尔-西伯利亚云、冷杉-西伯利亚松林界限附近.该河流盆地森林覆盖率高达98%.根据放射性碳年代测定,沉积涵盖了全新世大约自9000 yrs B.P.以来的大部分地层.主要运用化石植物群组成来恢复这一地区全新世以来的植被和气候变化,通过某些化石植物群的全部植物种类的现代地理分布的分析,可以发现与过去植被最接近的现代对应植被类型的位置,通过确定所有植物种现代生长地区的景观和气候来推测与古环境最接近的景观和气候.整个孢粉组合序列中云杉、松和桦占统治地位,但是植物群的成分和植被有变化.暖温带树种,如椴、榆及栎等在森林中的含量有变化,在全新世最暖期,相当于中晚大西洋期(6000-4500 yrs B.P.)达到最高.这些变化通过对应的现代植物群在俄罗斯平原的"迁移"反映出来,从中、南乌拉尔向西至Sukhona河盆地然后再返回到研究区的Vychegda河下游.运用古植物群的方法定量恢复的主要气候指标表明在大西洋期7月份月均温比现代高2.5℃,1月份月均温比现在高出1℃,年降雨量和现在接近.这段时间可以认为是本地区全新世的气候最适宜期.     

Postfire Succession of Mire Ecosystems Reconstructed Using Paleoecological Analysis: A Case Study of Novoaleksandrovskoe Mire (Meshchera Lowland,Ryazan Oblast)

Patterns of medium-term (decades) postfire succession of a mire ecosystem were studied using multiproxy paleoecological analysis. The resistance of mire ecosystems featuring thick peat deposits to fires due to surface and patchy incineration has been noted. It was found that, in favorable climatic conditions (i.e., sufficient precipitation), the vegetation cover recovers and the vertical growth and development towards oligotrophication are resumed within a medium-term period.     

Fluxes of biomass and essential polyunsaturated fatty acids from water to land via chironomid emergence from a mountain lake

The taxonomic composition, seasonal dynamics, and emergence intensity of chironomid adults (the Chironomidae family) emerging from Oiskoe mountain oligotrophic lake (Western Sayan, Southern Siberia) have been established. The value of the annual emergence of chironomid adults averages 0.42 g wet weight m^-2 in the lake area and approaches the value of potential emergence, which is calculated based on the estimate of zoobenthos secondary production. For the first time the fatty-acid composition and contents of essential omega-3 polyunsaturated fatty acids (PUFAs) are compared between the larvae and adult stages of chironomids. The PUFA content per wet weight unit in adults is more than 7 times higher than that in larvae. The PUFA flux per lake area unit resulting from the chironomid emergence amounted to 1.752 mg m^-2 y^-1, which is over 10 times lower than the global estimate for the emergence of amphibiotic insects. Calculations show that the PUFA flux brought with the chironomid emergence per land unit of the studied mountain territory is very low when compared to that for other landscapes, with the exception of the shoreline part of the territory with a width of 15 m, in which the PUFA flux is comparable to that in productive landscapes.     

Sandoglobulin immunocorrection in trauma

Twenty one patients with the long-term compression syndrome (LCS) and 12 patients with burns treated with sandoglobulin in combination with antibacterial therapy were followed up. The control groups included 14 and 18 patients, respectively. All the patients had wound infections. Increased or lowered respiratory burst of peripheral blood neutrophils and lowered contents of active T-lymphocytes were detected in the majority of the patients. The patients had also an increased respiratory burst of tissue homogenate in the primary focus. Sandoglobulin decreased the periods of normalization of the immunological indices, body temperature and leukogram shifts to the right. The most pronounced effect of the drug was recorded before radical operations, i.e. in the presence of acute microbial toxemia or in patients with severe and extended burns. The procedure of immunological monitoring developed by the authors rapidly estimates the indications to the use of sandoglobulin alone or in combination with other immunomodulators.     

Physico-chemical properties of ribonuclease A modified with pyridoxal-5'-phosphate]

The physico-chemical properties have been studied of RNase A selectively modified at the E-NH2-group of Lys-7 and Lys-41 with pyridoxal-P. Modification did not affect conformational stability of the protein globule, thus all changes in the molecule of the modified RNase A were localised around the alkylated Lys residue. In the both cases pyridoxyl-P. The residue was shown to be localized in the active site region of the (P-Pxy)-Lys-7-RNase A and its chromophore parts was highly exposed to the solvent. (P-Pxy) E-Lys-7-RNase A and its chromophore parts was highly exposed to the solvent. In the Lys-41 derivative, pyridoxamine-P was situated exactly in the active site and is partially hidden in the protein grobule. The pH-dependence of absorption spectra indicates that the chromophore of pyridoxyl-P in modified proteins is quite sensible to the ionic state of its surrounding. The usefulness of pyridoxyl-P as a reporter group was proved in the study with (P-Pxy)-Lys-7-RNase A. Some conformational changes involving His-119 were shown to take place in the course of the enzyme-nucleotide complex formation.     

Mechanism of anion-cation selectivity of amphotericin B channels

Summary Zero current potential and conductance of ionic channels formed by polyene antibiotic amphotericin B in a lipid bilayer were studied in various electrolyte solutions. Nonpermeant magnesium and sulphate ions were used to independently vary the concentration of monovalent anions and cations as well as to maintain the high ionic strength of the two solutions separated by the membrane. Under certain conditions the channels select very strongly for anions over cations. They are permeable to small inorganic anions. However, in the absence of these anions the channels are practically impermeable to any cation. In the presence of a permeant anion the contribution of monovalent cations to channel conductance grows with an increase in the anion concentration. The ratio of cation-to-anion permeability coefficients is independent of the membrane potential and cation concentration, but it does depend linearly on the sum of concentrations of a permeant anion in the two solutions. These results are accounted for on the assumption that a cation can enter only an anion-occupied channel to form an ionic pair at the center of the channel. The cation is also assumed to slip past the anion and then to leave the channel for the opposite solution. This model with only few parameters can quantitatively describe the concentration dependences of conductance and zero current potential under various conditions.