Cytological peculiarities of some extremely halophilic soil archaeobacteria

Ultrastructure and morphogenesis of extremely halophilic neutrophilic (Halobacteriam distributum, Halococcus turkmenicus) and alkaliphilic (Natronobacterium pharaonis, Natronococcus occultus) archaeobacteria were studied. The H. distributum culture was rather polymorphous and produced cells of four types. Due to the irregular cell fission in different planes packages of various numbers of cells surrounded by a common capsule were formed. Resting forms (halocysts) with multilayer covers were present in the population. The N. pharaonis culture consisted of rod-like cells and cyst-like forms. Besides, under conditions of carbon limitation, multicellular aggregated forms were found in the culture. Encapsulated single cells and aggregated forms with a common capsule were observed in H. turkmenicus and N. occultus cultures.     

Expression of Frankia nif genes in nodules of Alnus glutinosa

Expression of Frankia genes involved in nitrogen fixation was studied in Alnus glutinosa nodules using the in situ hybridization technique. The results show that high level expression of nif genes does not occur immediately upon infection of cortical cells by Frankia. Also, only in the infected cells near the tips of the nodule lobes, nif genes are expressed at high levels. In the majority of infected cells, nif gene expression is rather low.     

Evaluation of glycoconjugates on the K562 cell surface by means of lectin binding — comparison with human erythrocytes

The binding of five radiolabelled lectins (Vicia graminea, peanut,Phaseolus vulgaris isolectins E-PHA and L-PHA,Evonymus europaeus) to untreated and desialylated K562 cells and human erythrocytes was compared. The number of glycophorin A receptors recognized on the K562 cells by anti-blood group NV. graminea lectin was comparable to that found on the MN or NN erythrocyte surface. However, K562 cells had a severalfold higher number of oligosaccharide chains (presumablyO-glycosidic) which after desialylation became high-affinity receptors for peanut agglutinin, and of complex typeN-glycosidic chains available for the reaction with E-PHA and also with L-PHA (the latter lectin was not bound to erythrocytes). Moreover, K562 cells not treated with neuraminidase had a significant amount of extremely low affinity receptors for peanut agglutinin, whereas binding of this lectin to untreated erythrocytes was undetectable. On the other hand, the untreated K562 cells did not bind anti-blood group B and HE. europaeus lectin, but a small amount of binding by the desialylated cells was observed. Some other differences observed in the mode of lectin binding to K562 cells and erythrocytes are discussed.     

Trypanocidal properties, structure-activity relationship and computational studies of quinoxaline 1,4-di-N-oxide derivatives

Pyrazole and propenone quinoxaline derivatives were tested against intracellular forms of Leishmania peruviana and Trypanosoma cruzi. Both series were tested for toxicity against proliferative and non-proliferative cells. The pyrazole quinoxaline series was quite inactive against T. cruzi; however, the compound 2,6-dimethyl-3-f-quinoxaline 1,4-dioxide was found to inhibit 50% of Leishmania growth at 8.9 μM, with no impact against proliferative kidney cells and with low toxicity against THP-1 cells and murine macrophages. The compounds belonging to the propenone quinoxaline series were moderately active against T. cruzi. Among these compounds, two were particularly interesting, (2E)-1-(7-fluoro-3-methyl-quinoxalin-2-yl)-3-(3,4,5-trimethoxy-phenyl)-propenone and (2E)-3-(3,4,5-trimethoxy-phenyl)-1-(3,6,7-trimethyl-quinoxalin-2-yl)-propenone. The former possessed selective activity against proliferative cells (cancer and parasites) and was inactive against murine peritoneal macrophages; the latter was active against Leishmania and inactive against the other tested cells. Furthermore, insilico studies showed that both series respected Lipinski’s rules and that they confirmed a linear correlation between trypanocidal activities and LogP. Docking studies revealed that compounds of the second series could interact with the poly (ADP-ribose) polymerase protein of Trypanosoma cruzi.     

大型海藻龙须菜抽提液对褶皱臂尾轮虫生命表参数的影响

大型海藻富含多种活性物质,具有抗衰老等生物活性;轮虫是良好的潜在抗衰老研究模式生物。本研究以褶皱臂尾轮虫(Brachionus plicatilis)作为实验对象,研究了不同浓度的大型海藻龙须菜抽提液(0,250,500,750,1000 mg/L)和不同浓度的食物(蛋白核小球藻和普通小球藻)对褶皱臂尾轮虫生命表参数的影响。结果表明:与对照组相比,食物浓度为1.0×10~6个/mL蛋白核小球藻时,不同浓度龙须菜抽提液对轮虫产卵数、平均寿命、净生长率以及世代时间有显著促进效应(P0.05);轮虫平均产卵数及寿命在龙须菜抽提液浓度750 mg/L处达到最高,分别为16只和13.9d(P0.05)。食物浓度为2.0×10~6个/mL普通小球藻时,轮虫平均产卵数和寿命在抽提液浓度为500 mg/L处达到最高,分别为16只和13.6d(P0.05),轮虫平均寿命和净生长率均有显著提高(P0.05)。相同龙须菜抽提液浓度下,食物浓度为1.0×10~6个/mL蛋白核小球藻下轮虫的净生长率、世代时间均显著高于食物浓度为2.0×10~6个/mL蛋白核小球藻培养的轮虫(P0.05);食物浓度为2.0×10~6个/mL时,普通小球藻培养轮虫的净生长率和世代时间均显著高于蛋白核小球藻实验组(P0.05)。交互作用分析显示,龙须菜抽提液与小球藻的交互作用对褶皱臂尾轮虫的内禀增长率有显著影响(P0.05)。研究结果表明,大型海藻龙须菜抽提液对褶皱臂尾轮虫的生长与生殖有促进作用,延长轮虫寿命。     

Co-cultivation of plant cells as a technique for the elicitation of secondary metabolite production

Cells of Mikania glomerata, Cephaelis ipecacuanha and Maytenus aquifolia were co-cultured in a two-phase system using filter paper as a solid support. The species were co-cultured in all possible paired combinations. Interaction between Mikania and Maytenus cells resulted in increased biomass production of Maytenus cells, but the friedelin content was reduced. Co-cultivation of Cephaelis and Mikania cells enhanced coumarin content, but inhibited the growth of Mikania cells. However, yield of emetine as well as Cephaelis biomass accumulation were positively stimulated by the co-cultivation. Results indicate a possible occurrence of allelopathy in such a system. This revised version was published online in June 2006 with corrections to the Cover Date.     

Uptake of volatilen-alkanes byPseudomonas PG-I

Using a bacterial speciesPseudomonas PG-1, evidence has been obtained which indicates that uptake ofn-pentane ton-octane by microbial cells takes place primarily from the gas phase either directly orvia the aqueous phase. Specific growth rate increased along with the increase in substrate concentration but above the alkane concentration of 0.3% by volume, specific growth rate decreased indicating substrate inhibition of growth. In the case of less volatile alkanes,n-nonane andn-decane, substrate transfer is predominantly through substrate solubilization system elaborated by the cells. EDTA, a strong inhibitor of hydrocarbon solubilization by the cells, inhibited growth on these two alkanes but had negligible effect on growth onn-pentane ton-octane.     

N-andO-glycosylation of glycoprotein C synthesized by Herpes simplex virus type 1-infected ricin resistant cells

The progeny of Herpes simplex virus type 1 (HSV-1) grown in ricin-resistant 14 cells (Ric^R14) lackingN-acetylglucosaminyltransferase I was released in the extracellular medium at a very low rate. By using a monoclonal antibody immobilized on Sepharose we purified from HSV-1-infected Ric^R14 cells a viral glycoprotein (gC), which carries bothN-andO-linked oligosaccharides. Glycopeptides obtained from [³H]mannoselabeled gC by Pronase digestion were entirely susceptible to endo--N-acetylglucosaminidase H, and the major oligosaccharide released was Man₄GlcNAc. The accumulation of this high-mannose species was related to the enzymic defect of the host cells and to the long retention of the viral glycoprotein within the cells. The extent ofO-glycosylation evaluated in [¹⁴C]glucosamine-labeled gC from Ric^R14 cells as compared to that of gC from wild type cells did not appear to be significantly modified.Abbreviations Con A concanavalin A - BHK cells baby hamster kidney cells - HSV Herpes simplex virus     

Binding and penetration ofRhizobium japonicum to cultured soybean cells

A cultured soybean cell line, SB-1 was used to evaluate the initial interaction between the soybean cells andRhizobium japonicum. Co-culturing ofR. japonicum with SB-1 cells in suspension resulted in strain-specific polar attachment. This attachment can be inhibited by galactose and antibodies raised against seed soybean agglutinin (SBA). A lectin was purified from SB-1 cells which shares properties with SBA in terms of immunological reactivity, sugar binding activity, polypeptide molecular weight and peptide maps. When the SB-1 cells were co-cultured withR. japonicum for three weeks in solid agar medium, histological staining revealed bacterial penetration into certain SB-1 cells. Furthermore, there were focal regions of cells with prominent nuclei representing actively proliferating regions. These observations are analogous to that ofin vivo nodule initiation in soybean roots.     

Variations in the amino acid composition of cyanophycin in the cyanobacterium Synechocystis sp. PCC 6308 as a function of growth conditions

Gas chromatography-mass spectrometry studies of the nitrogen isotopic composition of the N-trifluoroacetyl n-butyl ester derivatives of the amino acids from isolated hydrolyzed cyanophycin from ¹⁵N-enriched cells led to two major findings: (1) the amino acid composition of this granular polypeptide, isolated using procedures optimized for extracting and purifying cyanophycin from cells in the stationary growth phase, varied with the culture growth condition; (2) the rate of incorporation of exogenous nitrate differed for each nitrogen atom of the amino acid constituents of cyanophycin or cyanophycin-like polypeptide. Arginine and aspartic acid were the principle components of cyanophycin isolated from exponentially growing cells and from light-limited stationary phase cells, with glutamic acid as an additional minor component. The cyanophycin-like polypeptide from nitrogen-limited cells contained only aspartic and glutamic acids, but no arginine. The glutamic acid content decreased and arginine content increased as nitrate was provided to nitrogen-limited cells. These cells rapidly incorporated nitrate at different rates at each cyanophycin nitrogen site: guanidino nitrogens of arginine>aspartic acid >-amino nitrogen of arginine>glutamic acid. Little media-derived nitrogen was incorporated into cyanophycin of exponentially growing cells during one cellular doubling time.Abbreviations asp-TAB, glu-TAB, arg-TAB N-Trifluoroacetyl n-butyl ester derivatives of aspartic acid, glutamic acid and arginine, respectively - CAP chloramphenicol - CF correction factor - TFAA Trifluoroacetic anhydride - MBTFA N-Methyl-bis-trifluoroacetamide     

Japanese species of Hypomyces and its anamorph III

Three new species of Hypomyces with KOH-negative subiculi occurring on the Aphyllophorales are described. Hypomyces pseudocorticiicola is characterized by a grayish-yellow to brown subiculum, fusiform ascospores, always with one septum, and its Cladobotryum-anamorph. Hypomyces laeticolor is characterized by a bright-colored subiculum, small apiculi on the ascospores, and well-developed verticillate conidiogenous cells. Hypomyces penicillatus forms a Trichothecium-like anamorph with well-developed verticils of conidiogenous cells.     

Redundancy of interleukin-6 in the differentiation of T cell and monocyte subsets during cutaneous leishmaniasis

Leishmania (L.) major is a protozoan parasite that infects mammalian hosts and causes a spectrum of disease manifestations that is strongly associated with the genetic background of the host. Interleukin (IL)-6 is an acute phase proinflammatory cytokine, known in vitro to be involved in the inhibition of the generation of regulatory T cells. IL-6-deficient mice were infected with L. major, and T cell and monocyte subsets were analyzed with flow cytometry. Our data show that at the site of infection in the footpad and in the draining popliteal lymph node, numbers of regulatory T cells remain unchanged between WT and IL-6-deficient mice. However, the spleens of IL-6^−/− mice contained fewer regulatory T cells after infection with L. major. The development of cutaneous lesions is similar between WT and IL-6-deficient mice, while parasite burden in IL-6^−/− mice is reduced compared to WT. The development of IFN-γ or IL-10 producing T cells is similar in IL-6^−/− mice. Despite a comparable adaptive T cell response, IL-6-deficient mice develop an earlier peak of some inflammatory cytokines than WT mice. This data indicate that the role of IL-6 in the differentiation of regulatory T cells is complex in vivo, and the effect of an absence of this cytokine can be counter-intuitive.     

中国早熟禾属植物部分种叶下表皮微形态的研究

通过光学显微镜及扫描电子显微镜对中国早熟禾属20种、6亚种及2变种植物的叶下表皮微形态特征进行了观察, 以明确叶表皮微形态特征在早熟禾属植物中的分类学意义。结果显示：(1)早熟禾属植物的叶下表皮长细胞多为长筒状或纺锤形,少数短筒状,细胞壁波状弯曲或近平直;脉间具有短细胞或缺如;气孔器多数常见,副卫细胞平行形至低圆屋顶形;脉上具有刺细胞或缺如,脉间刺细胞多为缺如;脉上硅细胞单生或对生,椭圆形、肾形、新月形、近方形、长方形边缘波状弯曲或结节形;部分早熟禾属植物叶下表皮存在冠细胞。(2)早熟禾属植物叶下表皮微形态特征在长细胞的形状及其细胞壁的弯曲与否、短细胞的有无及其形状、气孔器的分布与副卫细胞的形状、刺细胞的分布、脉上硅细胞的形状、冠细胞的有无这些方面存在着一定的差异,可为该属植物种间分类提供参考依据。叶表皮微形态证据支持高原早熟禾、细叶早熟禾作为草地早熟禾亚种的处理意见。     

In vivo Testing of Functional Properties of Three Selected Probiotic Strains

Summary Lactobacillus acidophilus M92, Lactobacillus plantarum L4 and Enterococcus faecium L3 were previously selected as probiotic strains on the base of in vitro selection criteria. To investigate functional properties of these three probiotic strains in vivo, Swiss albino mice were used as animal model. Survival, competition, adhesion and colonization were monitored in the gastrointestinal tract, as well as the immunomodulating capability of L. acidophilus M92, L. plantarum L4 and E. faecium L3. During the feeding of mice with probiotic strains with daily dose of 2 × 10¹⁰ rifampicin-resistant cells, the number of lactic acid bacteria in the faeces increased and reduction of enterobacteria and sulphite-reducing clostridia was observed. Rifampicin-resistant colonies of probiotic strains could be reisolated from the faeces of mice fed with the rifampicin-resistant cells. The similar results were obtained in homogenates of small and large intestine of mice on the first and fourteenth days after feeding with L. acidophilus M92, L. plantarum L4 and E. faecium L3. The adherence of the probiotic strains obtained in vitro correlated with their capability to adhere to mouse ileal epithelial cells in vivo. After oral immunization of mice with viable cells of L. acidophilus M92, L. plantarum L4 and E. faecium L3 with a daily dose of 2 × 10¹⁰ cells, the concentrations of serum IgA, IgG and IgM antibodies from all groups of mice were significantly higher in comparison to the control.     

Red cell H-deficient,salivary ABH secretor phenotype of Reunion island. Genetic control of the expression of H antigen in the skin

Based on the genetic model proposing thatH andSe are two structural genes, we predicted that the red cell H-deficient, salivary ABH secretor phenotype should be found on Reunion island, where a large series of H-deficient non-secretor families have been previously described. Two such Reunion individuals are now reported. POU [A_h, Le(a–b+), secretor of A, H, Le^a and Le^b in saliva] and SOU [O_h, Le(a–b+), secretor of H, Le^a and Le^b in saliva]. Both are devoid of H -2-fucosyltransferase activity in serum. In addition, the preparation of total non-acid glycosphingolipids from plasma and red cells of POU revealed the type 1ALe^b heptaglycosylceramide and small amounts of the monofucosylated type 1 A hexaglycosylceramide. Both glycolipids possess an H structure probably synthesised by the product of theSe gene. No other blood group A glycolipids, with types 2, 3 or 4 chains, normally present in the presence of the product of theH gene, were found on red cells or plasma of POU.TheH,Se andLe genetic control of the expression of ABH and related antigens in different tissue structures of the skin is described in 54 H-normal individuals of known ABO, secretor and Lewis phenotypes; in one red cell H-deficient salivary secretor (SOU); and in one H-deficient non-secretor (FRA). Sweat glands express ABH under the control of theSe gene. Sweat ducts express ABH under the control of bothH andSe genes and Lewis antigens under the control ofLe and bothH andSe genes. Epidermis, vascular endothelium and red cells express ABH under the control of theH gene. The products ofH andSe genes are usually expressed in different cells. However, the results illustrate that in some structures, like the epithelial cells of sweat ducts, both the products ofH andSe genes can contribute to the synthesis of the same Le^b structure.     

Expression pattern of annelid <Emphasis Type="Italic">Zic</Emphasis> in embryonic development of the oligochaete <Emphasis Type="Italic">Tubifex tubifex</Emphasis>

Embryonic expression of a Zic homologue (Ttu-Zic) was examined in the oligochaete annelid Tubifex tubifex. The body plan of T. tubifex is characterized by obvious segmentation in the ectoderm and mesoderm. Ttu-Zic expression is detected in the mesodermal germ band and a subset of micromere descendants. Ttu-Zic is transiently expressed in primary m-blast cells (i.e., founder cells of mesodermal segments) as early as the time of their birth from M teloblasts. During its development, each mesodermal segment experiences two additional phases of Ttu-Zic expression. Ttu-Zic expression in micromere descendants is seen on the anterior surfaces of embryos undergoing teloblastogenesis; subsequently, these cells proliferate to form bilateral clusters, which then become internalized. Finally, clusters of Ttu-Zic-expressing cells are found in the center of the prostomium, corresponding to the cerebral ganglion. The Ttu-Zic expression profile in the early embryogenesis of T. tubifex may be homologous to those of evolutionarily distant animals.     

Carbohydrate exposure of human promyelocytic HL60 cells and histiocytic U937 cells during phagocytic differentiation assessed with fluoresceinated lectins

The display of carbohydrate structures was measured in promyelocytic HL60 cells and in histiocytic U937 cells induced to differentiate to phagocytic cellsin vitro during three to seven days of cultivation in the presence of dimethylsulfoxide (DMSO). It was assessed by micro-or spectrofluorometric quantification of the binding of fluorescent lectins. Changes in the cell size and the association and uptake of IgG-or complementopsonized yeast cells (Saccharomyces cerevisiae) were used as signs of phagocyte differentiation.The binding of wheat germ agglutinin (WGA), concanavalin A (Con A),Ricinus communis agglutinin-I (RCA-I) andUlex europaeus agglutinin-I (UEA-I) varied due to the presence of DMSO during cultivation, and without DMSO also on the number of days in culture and the type of cell.Abbreviations DMSO dimethylsulfoxide - PMA phorbol 12-myristate 13-acetate - KRG Krebs-Ringer phosphate buffer with glucose - WGA wheat germ agglutinin - Con A concanavalin A - RCA-I Ricinus communis agglutinin-I - UEA-I Ulex europaeus agglutinin-I     

The presence of inhibitors of the reproduction of Varroa jacobsoni Oud. (Gamasida: Varroidae) in infested cells

The mite Varroa jacobsoni was reared in artificial gelatin cells under laboratory conditions and the possible presence of factors inhibiting Varroa reproduction was studied. In cells infested with three mites, the mean offspring per female was reduced to 75% of that in singly infested cells. When gelatin cells were used for two successive rearing cycles, both the proportion of reproducing females and the offspring per reproducing female were significantly lower in cells that had contained an infested larva during the first rearing cycle than in those with an uninfested larva. The mean reduction of the offspring per female was 48%; this suggests that inhibitors of the reproduction are released into infested cells. Treatment of gelatin cells with the hexane extract of cells in which an infested bee pupa had developed caused a 21% reduction in the mean offspring per female, with a difference close to the significance level (p=0.07).     

Secretory avocado idioblast oil cells: evidence of their defensive role against a non-adapted insect herbivore

We tested the hypothesis that avocado idioblast oil cells play a defensive role against herbivorous insects. Toxicities of the intact avocado idioblast oil cells and the extracted idioblast oil were compared for three insect herbivores. Spodoptera exigua (Hübner) larvae are generalists that do not feed on avocados. By contrast, Sabulodes aegrotata (Guenée) and Pseudoplusia includens (Walker) larvae are generalist herbivores that readily feed on avocados. All bioassays were performed at a naturally occurring concentration of idioblast oil cells (2% w/w). Choice experiments showed that S. exigua larvae avoided diet treated with avocado idioblast oil cells and consume more control than treated diet. In contrast, idioblast oil cells had no significant antifeedant effects on the adapted S. aegrotata and P. includens larvae. Subsequent experiments designed to assess resistance mechanisms separated pre-ingestive (behavioral) and post-ingestive (physiological) effects of the avocado idioblast oil cells, and the extracted idioblast oil, on the two adapted herbivores. Post-ingestive adaptation was the mechanism that allows feeding. Because the impact of the avocado idioblast oil cells was greatest on the performance of non-adapted S. exigua, additional experiments determined that larvae fed diet containing the oil cells had higher mortality and reduced larval growth compared to controls. Developmental times were significantly prolonged for the survivors. Thus, increased mortality, reduced developmental rates, and antifeedant activity in the non-adapted insect indicate that defense against non-adapted herbivores may be an important function of idioblast cells in avocados.