Distribution of Adult Male and Female Baccharis concinna (Asteraceae) in the Rupestrian Fields of Serra Do Cipó, Brazil

Abstract: This study focuses on the sex ratio and spatial distribution of males and females in three populations of the endemic and restricted tropical dioecious shrub, Baccharis concinna (Asteraceae) in the mountainous region of Serra do Cipó, southeastern Brazil. The proportion of female plants in the population at lower elevation (1000 m a.s.l.) was significantly greater than of male plants. At this elevation of P/N and Ca/Al ratios in the soil were also greater indicating better nutritional status of the soils. The concentration of aluminium increased significantly with the elevation ( p < 0.001), perhaps rendering soils less conducive to female plants at higher elevations. Female plants are possibly adversely affected to a greater extent by soil quality than male plants. The spatial distribution of the populations within habitat was tested by the K(t) function, where the neighbourhood of a given individual was defined by a circle with a radius (t) up to 3 m. Despite the strong tendency for aggregation, the distribution of the sexes within habitats was random and the hypothesis was not supported. The independent distribution of the sexes within habitats may be explained by nutrient homogeneity of the soils, as well as by an absence of antagonism between the sexes. Nevertheless, we found a trend for males and females to be aggregated according to their gender.     

Expression of the β-subunit of β-conglycinin in seeds of transgenic plants

Soybean (<i>Glycine max</i> (L.) Merr.) seeds contain the storage protein <i><img src="/content/hj14657847718t20/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-conglycinin, encoded by a multigene family. <i><img src="/content/hj14657847718t20/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-Conglycinin consists of three subunits; <img src="/content/hj14657847718t20/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"><img src="/content/hj14657847718t20/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">, <img src="/content/hj14657847718t20/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">, and <i><img src="/content/hj14657847718t20/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>. A genomic clone for a <i><img src="/content/hj14657847718t20/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-subunit of <i><img src="/content/hj14657847718t20/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-conglycinin has been characterized by restriction-enzyme mapping and hybrid selected in-vitro translation followed by immunoprecipitation. In order to determine the developmental regulation of this <i><img src="/content/hj14657847718t20/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-subunit gene, its expression was studied in seeds of transgenic petunia (<i>Petunia hybrida</i>) and tobacco (<i>Nicotiana tabacum</i> L.) plants. The <i><img src="/content/hj14657847718t20/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-subunit expressed in seeds of petunia and tobacco was recognized by anti-<i><img src="/content/hj14657847718t20/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-conglycinin serum at a relative molecular mass of 53 000, equivalent to that of the native protein. Separation of the petunia-seed proteins by isoelectric focusing followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis showed that multiple isoelectric forms of the <i><img src="/content/hj14657847718t20/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-subunit were produced. There was approximately a twofold variation in the accumulation of the <i><img src="/content/hj14657847718t20/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-subunit protein in the mature seeds of transgenic petunia plants, each containing a single <i><img src="/content/hj14657847718t20/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-subunit gene. However, the level of protein accumulation in mature seeds and the amount of <i><img src="/content/hj14657847718t20/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-subunit mRNA in developing seeds was not correlated. Accumulation of the <i><img src="/content/hj14657847718t20/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-subunit protein in transgenic seeds was less than the <img src="/content/hj14657847718t20/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"><img src="/content/hj14657847718t20/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-subunit protein that accumulated in transgenic petunia seeds containing a single <img src="/content/hj14657847718t20/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"><img src="/content/hj14657847718t20/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-subunit gene and less than the amount of the <i><img src="/content/hj14657847718t20/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-subunit in mature soybean seeds which contain 8–13 <i><img src="/content/hj14657847718t20/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-subunit genes. In transgenic tobacco plants, the accumulation of the <i><img src="/content/hj14657847718t20/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>-subunit protein in seeds was generally well correlated with the number of genes that were incorporated in the different transformants.Abbreviations kb kilobase - kDa kilodalton - M<sub>r</sub> relative molecular mass - SDS-PAGE sodium dodecyl sulfate polyacrylamide gel electrophoresis     

C-banding polymorphism and the analysis of nucleolar activity in Dasypyrum villosum (L.) Candargy,its added chromosomes to hexaploid wheat and the amphiploid Triticum dicoccum — D. villosum

Summary C-banding patterns and nucleolar activity were analyzed in <i>Dasypyrum villosum</i>, its added chromosomes to hexaploid wheat and the hexaploid amphiploid <i>Triticum dicoccum-D. villosum</i>. Two different populations of the allogamous species <i>D. villosum</i> (2n= 14, VV) from Greece and Italy were analyzed showing a similar polymorphism for C-banding pattern. Six of the seven addition lines were identified by their characteristic C-banding pattern. No polymorphism between both members of each added alien chromosome was found. Furthermore, nucleolar activity and competition were studied by using silver staining procedure. In <i>D. villosum</i> only one chromosome pair, A, was found to be responsible for organizing nucleoli. The results obtained in the amphiploid and in the addition lines demonstrate that nucleolar activity is restricted to SAT-chromosomes 1B and 6B of wheat, while those of <i>D. villosum</i> remain inactive.     

Effect of transforming growth factor beta (TGF-β) on ATP citrate lyase in isolated hepatocytes

Summary Transforming growth factor beta (TGF-<img src="/content/h1314432126t4246/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">) activates ATP citrate lyase in freshly isolated rat liver hepatocytes in a time dependent manner. Maximal stimulation of the enzyme occurred with less than thirty minutes of incubation of the cells with TGF-<img src="/content/h1314432126t4246/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">. The half maximal effect on the enzyme determined in hepatocytes incubated with TGF-<img src="/content/h1314432126t4246/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"> for 10 min at 37°C was elicited by TGF-<img src="/content/h1314432126t4246/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"> concentrations in the 10<sup>–11</sup> – 10<sup>–12</sup> M range. The potential role of TGF-<img src="/content/h1314432126t4246/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"> stimulation of ATP citrate lyase activity in new membrane synthesis is discussed.     

Separation of chitosomes and secretory vesicles from the “slime” variant of Neurospora crassa

Cells from the <img src="/content/t18787603372n062/xxlarge8220.gif" alt="ldquo" align="MIDDLE" BORDER="0">slime<img src="/content/t18787603372n062/xxlarge8221.gif" alt="rdquo" align="MIDDLE" BORDER="0"> variant of <i>Neurospora crassa</i> were broken in isotonic conditions by use of triethanolamine buffer plus EDTA. After removal of large membranous structures by low-speed centrifugation, chitosomes and secretory vesicles were separated by means of gel filtration, precipitation of membranous contaminants with Concanavalin A, and centrifugation in sucrose or glycerol gradients. Polypeptidic composition of fractions enriched in secretory vesicles or chitosomes was found to be distinct. By these criteria we concluded that chitosomes and secretory vesicles represent different populations of microvesicles. Both microvesicular populations appeared free of endoplasmic reticulum and vacuolar contaminants as demonstrated by determination of appropriate enzymatic markers.Abbreviations ER Endoplasmic reticulum - UDP-GlcNAc uridine-5<img src="/content/t18787603372n062/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-diphosphate N-acetyl glucosamine - GlcNAc N-acetyl glucosamine - SDS sodium dodecyl sulfate - PMSF phenyl methyl sulfonyl fluoride - EDTA ethylene diamino tetraacetic acid Investigador Nacional de Mexico. On leave from the Centro de Investigacion y Estudios Avanzados (IPN), and the Universidad de Guanajuato, Gto., Mexico     

The organization of repetitive sequences in the albumin and alpha-fetoprotein gene loci in the rat

Summary The distribution of middle repetitive sequences in the genic and extragenic regions of the rat albumin and <img src="/content/t7l55v7372129272/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-fetoprotein genes was analyzed. Their presence was determined by probing Southern blots of restriction fragments of albumin and <img src="/content/t7l55v7372129272/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-fetoprotein genomic subclones with <sup>32</sup>P-labeled total rat DNA. Repetitive sequences were detected in both genes. They were classified as weak, moderate and intense hybridizing elements according to the intensity of hybridization. Weak repetitive sequences were characterized as dG·dT repeats by using <sup>32</sup>P-labeled poly-(dG·dT)(dC·dA) oligomer probe. They occurred in 5<img src="/content/t7l55v7372129272/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0"> and 3<img src="/content/t7l55v7372129272/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0"> extragenic regions of the two genes and in introns 4 and 5 of the albumin gene. The moderate repetitive sequence present in intron 6 of the albumin gene was identified as the rat SINES element, 4D12. The intense repetitive sequence, localized in the 3<img src="/content/t7l55v7372129272/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0"> non-coding region of the albumin gene, corresponded to the terminal segment of a rat high repeat long interspersed DNA family, L1Rn. 4D12 and L1Rn sequences were also scattered throughout the <img src="/content/t7l55v7372129272/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-fetoprotein locus as moderate and intense repetitive elements, respectively, but their distribution was different from that of the albumin genomic region. These results indicate that repetitive sequences invaded the two loci in a non-conservative manner.     

Cellular origin and distribution of transforming growth factor-β1 in the normal rat myocardium

Summary Transforming growth factor-<i><img src="/content/m3347t697v5x7106/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i> (TGF-<i><img src="/content/m3347t697v5x7106/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i>) is a biologically active polypeptide present in normal tissues as well as transformed cells. Two structurally related forms of this peptide are TGF-<i><img src="/content/m3347t697v5x7106/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i> <sub>1</sub> and TGF-<i><img src="/content/m3347t697v5x7106/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i> <sub>2</sub>. Using freshly isolated cardiomyocytes and non-myocyte heart cells, and a [<sup>32</sup>P]-labelled cDNA probe to human TGF-<i><img src="/content/m3347t697v5x7106/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i> <sub>1</sub>, we demonstrated that mRNA for TGF-<i><img src="/content/m3347t697v5x7106/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i> <sub>1</sub> could be detected only in the nonmyocyte fraction of heart cells. In the present study, the distribution of TGF-<i><img src="/content/m3347t697v5x7106/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i> <sub>1</sub> in the heart was determined by immunofluorescence staining by use of a polyclonal antibody to porcine TGF-<i><img src="/content/m3347t697v5x7106/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i> <sub>1</sub> in cryostat sections of rat heart. Immunofluorescence staining was intense around the blood vessels and radially diffuse in the surrounding myocardium.     

Selective labeling of α-bungarotoxin with fluorescein isothiocyanate and its use for the study of toxin-acetylcholine receptor interactions

The main product of the reaction of fluorescein isothiocyanate (FITC) and bungarotoxin (Bgt) under near stoichiometric conditions is a monofluorescein derivative preferentially labeled at Lys 26, a highly conserved residue known to be involved in the binding (McDaniel, C. S., Manshouri, T., and Atassi, M. Z. (1987)<i>J. Prot. Chem.</i> <b>6</b>, 455–461; Garcia-Borron, J. C., Bieber, A. L., and Martinez-Carrion, M. (1987)<i>Biochemistry</i> <b>26</b>, 4295–4303) of postsynaptic neurotoxins specific for the nicotinic acetylcholine receptor (AcChR). The fluorescently labeled toxin retains a high affinity for the AcChR, and an unaltered specificity. Binding of FITC-Bgt to AcChR results in a significant decrease in the fluorescence intensity of the probe. This AcChR-mediated quenching of FITC-Bgt fluorescence allows for a continuous monitoring of the binding process. The quenching of free and bound FITC-Bgt by charged and neutral quenchers shows few fluorophore accessibility changes as induced by the toxin-bound state. The results are consistent with a model in which the positively charged concave surface of the toxin interacts with a negatively charged complementary surface in the receptor molecule.     

Core substructure in Mastigocladus laminosus phycobilisomes

A native high molecular complex (M<sub>r</sub> 850000) containing about 50% of the allphycocyanin of the phycobilisome but lacking allophycocyanin B was separated from isolated phycobilisomes by gel electrophoresis. It was designated AP<sub>CM</sub> since the large linker polypeptide L<sub>CM</sub> was exclusively localized in this complex. The complex exhibited a ?196°C fluorescence emission maximum at 673 nm (671 nm at 25°C). In addition, a core complex (designated AP<sub>C</sub>, M<sub>r</sub>≥1000000) consisting of both AP<sub>CM</sub> and AP 680 was isolated by combined gel filtration and linear gradient centrifugation. At 25°C this complex showed dual emission peaks at 670 and 680 nm demonstrating functional independence of the terminal emitters. A complex similar to AP<sub>CM</sub> can be isolated from phycobilisomes of <em>Anabaena variabilis</em>. This is evidence that AP<sub>CM</sub> is the constitutive center of the tricylindrical core of hemidiscoidal cyanobacterial phycobilisomes. Two models summarizing the structural and functional consequences of the results are presented in the discussion.