Modeling competition between Laurencia obtusa (Ceramiales,Rhodophyta) and Hypnea spinella (Gigartinales,Rhodophyta) at Cabo Frio Island,Rio de Janeiro,Brazil

The Lotka-Volterra competition model was used to represent the interaction between Laurencia obtusa and Hypnea spinella. A new model that considers effects of competition on algal carrying capacity is suggested. To test the models, data from field experiments conducted in an intertidal region at Cabo Frio Island, Rio de Janeiro, Brazil, were used. Both models showed that Hypnea was a stronger competitor than Laurencia. The model of interaction through the carrying capacity showed a stable coexistence between the algal populations and better represented the experimental data.     

闽北地区四代三化螟发生动态Fuzzy预测模型研究

根据Fuzzy数学原理和三化螟生物学特性,组建了四代三化螟发生动态综合预测模型经对福建省将乐县16年四代三化螟发生期、发生量回报及1995年的预报,拟合率及正确率均达100％。     

Use of diethyl squarate for the coupling of oligosaccharide amines to carrier proteins and characterization of the resulting neoglycoproteins by MALDI-TOF mass spectrometry

The 8-methoxycarbonyloctyl glycosides of GlcNAc, Gal1-4Glc, Fuc1-2Fuc1-3GalNac and Fuc1-2Gal1-3[Fuc1-4]GlcNac were converted to primary amines by reaction with neat ethylenediamine and then coupled to bovine serum albumin (BSA) using diethyl squarate as the connector. The average degree of incorporation of the sugar onto the protein, as well as the molecular weight distribution, could be conveniently determined using matrix assisted laser desorption ionization/time of flight (MALDI-TOF) mass spectrometry thus avoiding cumbersome structure-dependent colour-tests or analysis of cleaved ligand. The present coupling method has the advantages of proceeding under very mild conditions, yielding controlled incorporation values and can reliably be used for the coupling of very small amounts (mg) of oligosaccharide.This paper is dedicated to Sen-itiroh Hakomori on the occasion of his 65th birthday     

Occurrence of heavy metals,sodium, calcium,and potassium in human hair,teeth, and nails

Heavy metals in biological samples: nails, teeth, and hair were examined during 1991–1993. Investigations of biological samples (hairn=249 samples, teethn=145, nailsn=80 samples) were provided for inhabitants of selected towns in Beskid Śląski. The towns are small mountain towns in southern Poland: Wista, Szczyrk, Istebna, Koniaków, and Jaworzynka. The analysis of ANOVA and MANOVA variances were used for biological samples in the context of age, sex, and type of samples for 12 elements (Pb, Cd, Cr, Zn, Fe, Cu, Mn, Ni, Co, Ca, Na, and K). The matrix correlation and cluster analysis were applied to explain the behavior of metals in human hair, teeth, and nails.     

The heat shock cognate 80 gene of tomato is flanked by matrix attachment regions

Matrix attachment regions (MARs) are thought to participate in the organization and segregation of independent chromosomal loop domains. Although there are several reports on the action of MARs in the context of heterologous genes, information is more limited on the role of MARs associated with plant genes. Transgenic studies suggest that the upstream, intron and downstream regions of the developmentally regulated heat shock cognate 80 gene (HSC80) of tomato participate in chromatin organization. In this study, we tested the in vitro affinity of the HSC80 gene to chromosomal scaffolds prepared from shoot apices of tomato. We found that a 1.5 kb upstream region and a 1.4 kb downstream region, but not the intron region, are MARs. These MARs interact with tomato and pea scaffolds and bind regardless of the expression status of HSC80 in the tissue from which the nuclei were isolated. Comparison to two known yeast MARs ARS1 and CENIII, showed that the HSC80 5MAR binds more avidly to tomato scaffolds than ARS1, while no binding of CENIII was observed. Competition binding between the two HSC80 MARs indicated that the 5 MAR can outcompete the 3 MAR and not vice versa. Last, we observed that the interaction of the 3 MAR with the scaffold could result in an electrophoretic mobility shift resistant to SDS, protease, and phenol treatment. In conclusion, MARs whose binding properties can be clearly differentiated are closely flanking the HSC80 gene. The discovery of MARs in regions which have a distinct function in HSC80 transgenes but not in transient expression assays, is consistent with a chromosomal scaffold role in HSC80 gene regulation.     

刺激中缝背核调制小脑间位核神经元电活动

刺激中缝背核（ｄｏｒｓａｌｒａｐｈｅｎｕｃｌｅｕｓ,ＤＲ）可以引起小脑间位核（ｉｎｔｅｒｐｏｓｅｄｎｕｃｌｅｕｓ,ＩＮ）神经元抑制,兴奋和双相（抑制－兴奋和兴奋－抑制）３种不同类型的反应,其中以抑制反应为主（７６．０％）,多数细胞的反应潜伏期〈３０ｍｓ。ＩＮ细胞的自发放电频率为５－１２０Ｈｚ,自发放电频率高的神经元群体对ＤＲ刺激的反应率却比自发放电频率低的群体低。静脉注射５－ＨＴ２／１ｃ受体阻断剂     

Root,shoot and soil parameters required for process-oriented models of crop growth limited by water or nutrients

A review is given of the prospects for using process-oriented models of water and nutrient uptake in improving integrated agriculture. Government-imposed restrictions on the use of external inputs will increase the likelihood of (temporary) nutrient or water stress in crop production in NW Europe and thus a better understanding is required of shoot-root-soil interactions than presently available. In modelling nutrient and water uptake, three approaches are possible: 1) models-without-roots, based on empirically derived efficiency ratios for uptake of available resources, 2) models evaluating the uptake potential of root systems as actually found in the field and 3) models which also aim at a prediction of root development as influenced by interactions with environmental factors. For the second type of models the major underlying processes are known and research can concentrate on model refinement on the one hand and practical application on the other. The main parameters required for such models are discussed and examples are given of practical applications. For the third type of models quantification of processes known only qualitatively is urgently needed.     

Composition and organisation of extracellular matrices around germ tubes and appressoria ofColletotrichum lindemuthianum

Summary The ultrastructure and composition of the extracellular matrices (ECMs) associated with germ tubes and appressoria ofColletotrichum lindemuthianum have been examined. Flexuous fibres (fimbriae), up to 6 m long and 4–30 nm in diameter, protruded from the surface of germ tubes and appressoria. Anionic colloidal gold and lectin cytochemistry showed that ECMs of germ tubes and appressoria contain basic proteins, -D-mannose and -D-galactose residues. A monoclonal antibody, UB26, was raised to infection structures isolated from leaves ofPhaseolus vulgaris infected withC. lindemuthianum. UB26 recognised a protein epitope on two glycoproteins (M_r 133,000 and 146,000). Reductions in the M_r of these proteins after treatment with peptide-N-glycosidase and trifluoromethane sulphonic acid suggest that they carry N- and O-linked side-chains. Immunofluorescence and EM-immunogold labelling showed that glycoproteins recognised by UB26 were restricted to the ECMs around germ tubes and appressoria but fimbriae were not labelled. Unlike appressorial germ tubes formed in vitro, intracellular infection hyphae were not labelled, suggesting that the glycoproteins recognised by UB26 are not present on fungal structures formed within host cells. In liquid culture, these glycoproteins were not released into the medium, suggesting they are physically linked to the cell wall. Also, the glycoproteins were not removed from glass surfaces by ultrasonication. These results suggest that glycoproteins recognised by UB26 may be involved in the adhesion of germ tubes and appressoria to substrata. Our results show that the ECMs of germ tubes and appressoria differ markedly in structure and composition from those of conidia and intracellular hyphae, and that extracellular glycoproteins are associated with specific regions of the fungal cell surface.Abbreviations ECM extracellular matrix - BPA Bauhinia purpurea agglutinin - BSA bovine serum albumin - DIC differential interference contrast - FITC fluorescein isothiocyanate - GNL Galanthus nivalis lectin - GSI-B₄ Griffonia simplicifolia isolectin B₄ - HEPES (N-(2-hydroxyethyl)piperazine-N-(2-ethanesulphonic acid) - IIF indirect immunofluorescence - IPC isopycnic centrifugation - MAb monoclonal antibody - PEG polyethylene glycol - PBS phosphate buffered saline - PNGase peptideN-glycosidase - SDS-PAGE sodium dodecyl sulphate polyacrylamide gel electrophoresis - TCS tissue culture supernatant - TEM transmission electron microscopy - TFMS trifluoromethane sulphonic acid     

T cells in murine lupus: propagation and regulation of disease

MRL/Mp-lpr/lpr mice develop a spontaneous lupus syndrome, including hypergammaglobulinemia, autoantibodies, glomerulonephritis, and lymphadenopathy. To investigate the role of lymphocyte subsets in the pathogenesis of disease, lupus-prone MRL mice deficient in T cells, T cells, or both were generated. Mice deficient in T cells developed a partially penetrant lupus syndrome, characterized by lymphadenopathy, elevated levels of class-switched immunoglobulins, an increased incidence of antinuclear antibodies, and immune deposits in kidneys which progressed to renal insufficiency over time. In comparison to wild type animals, T cell-deficient animals developed an accelerated and exacerbated disease phenotype, characterized by accelerated hypergammaglobulinemia and enhanced autoantibody production and mortality. Repertoire analysis of these latter animals identified polyclonal expansion (V) of CD4+B220-cells. Mice lacking both and T cells failed to generate class-switched autoantibodies and immune complex renal disease. First, these findings demonstrate that murine lupus in the setting of Fas-deficiency does not absolutely require the presence of T cells, and they also suggest that a significant basis for MRL/lpr disease, including renal disease, involves T cell-independent, T cell dependent, polyreactive B cell autoimmunity, upon which T cell-dependent mechanisms aggravate specific autoimmune responses. Second, these data indicate that T cells partake in the regulation of systemic autoimmunity, presumably via their effects on CD4+B220-T cells that provide B cell help. Finally, these results demonstrate that MRL/lpr B cells, despite their intrinsic abnormalities, cannot per se cause tissue injury without T cell help.Abbreviations snRNPs small nuclear ribonucleoprotein particles     

Structured modelling of animal cells

Recent advances in computer technology have promoted the design and use of detailed, computer-based models for biological systems. For many non-biological systems, the complexity of such simulations may be considered inappropriate and unwieldy, but in biological systems, and more specifically in animal cell culture, this level of complexity simply mimics what is only beginning to be understood about metabolic processs. With this in mind, we contend that complex, structured models are vital tools in the investigation of fundamental biological processes. An example of such a simulation, which describes the commercial production of therapeutic proteins by animal cell cultures, is considered.