The cytotaxonomy ofEmilia spp. (Asteraceae: Senecioneae) occurring in Brazil

Analysis of several populations in a large part of the distribution area of the genusEmilia in Brazil has revealed only two species: the diploidE. sonchifolia and the tetraploidE. fosbergii. The more widely reportedE. coccinea was not found. They show a karyotype constancy in morphology and chromosome number (2n = 10 and 2n = 20, respectively), C-banding pattern and number of secondary constrictions. Some indications were found thatE. fosbergii may be an allopolyploid and that its ancestors had different genome sizes.     

Production,cross reactivity,and epitope analysis of monoclonal antibodies against rat kidney gamma glutamyltransferase

Eighteen IgGl monoclonal antibodies (blabs) have been produced against gamma-glutamyl transferase (GGT) from rat kidney. They were specific to the light subunit of the enzyme with affinity constants ranging from 0.3 to 7.5 10⁸ M^–1, while they did not react with GGT from other sources i.e. human and pig kidney, rat and guinea pig liver, suggesting species and organ specificity. Two of the blabs (N° 11 and 21) lost their immunoreactivities towards rat kidney GGT in the presence of N-acetyl-neuraminic acid, while immunoreactivities of the other blabs were unchanged. Furthermore, Mabs No 11 and 21 did not react with desialylated rat kidney GGT. These findings suggest that N-acetyl-neuraminic acid is involved in the epitopes recognized by these two Mabs.Abbreviations ELISA enzyme linked immunosorbent assay - GGT gamma-glutamyltransferase - Mab monoclonal antibody - SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis     

Analysis of acidic and basic chitinases from tobacco and petunia and their constitutive expression in transgenic tobacco

cDNA clones of messenger RNAs for acidic and basic chitinases were isolated from libraries of tobacco mosaic virus-infected Samsun NN tobacco and petunia. The tobacco cDNA clones for acidic chitinase fell into two different groups, whereas all petunia cDNA clones had the same sequence. Also, tobacco genomic clones were isolated and one was characterized. This genomic clone, corresponding to one of the cDNA clones, showed that this acidic chitinase gene contains two introns. The amino acid sequences of the acidic chitinases from tobacco, as deduced from the cDNA clones, fully agreed with partial sequences derived from peptides obtained from purified tobacco-derived pathogenesis-related proteins PR-P and PR-Q. The deduced amino acid sequences showed that PR-P and PR-Q are 93 and 78%, respectively, identical to the petunia enzyme. All deduced chitinase sequences indicated the presence of an NH2-terminal, highly hydrophobic signal peptide. In addition, the polysaccharide-binding domain present at the NH2-terminus of basic chitinases from mature tobacco is not present in these acidic chitinases. Furthermore, the complete coding sequence for the petunia chitinase, constructed downstream of the cauliflower mosaic virus 35S promoter, was used to transform tobacco. The resulting chimeric gene was constitutively expressed, and the petunia enzyme was targeted to the extracellular fluid. In contrast, a basic chitinase of tobacco, expressed from a chimeric gene, was found in total leaf extracts but not in preparations of extracellular fluid.     

Comparative analysis of the lipopolysaccharides of a rough and a smooth strain of Pseudomonas syringae pv. phaseolicola

The lipopolysaccharides (LPS) of a rough (R) and a smooth (S) strain of Pseudomonas syringae pv. phaseolicola were analysed. The S-LPS revealed markedly more rhamnose and fucose, but less glucose, than the R-LPS. The presence of 3-O-methyl-rhamnose (acofriose) in the S-LPS was confirmed by cochromatography with authentic acofriose. SDS polyacrylamide gel electrophoresis of the S-LPS demonstrated a cluster of regularly spaced high molecular weight fractions, which was almost lacking in the R-LPS. The main fatty acids of the lipid A of both LPS species were 3-OH-10:0,3-OH-12:0,2-OH-12:0, and 12:0. Two N-linked diesters were demonstrated: 3-O(12:0)-12:0 and 3-O(2-OH-12:0)-12:0. S-LPS was subjected to mild hydrolysis and the degraded polysaccharide separated into three fractions by gel permeation chromatography on a Fractogel TSK HW-50 column. Fraction I, representing nearly only the O-specific side chain, consisted of rhamnose and fucose in a molar ratio of 4:1, with 4% of the rhamnose being 3-O-methylated (acofriose). Fraction II, representing mostly core material, was composed of glucose, rhamnose, heptose, glucosamine, galactosamine, alanine, and a still unidentified amino compound, in an approximate molar ratio of 3:1:1:1:1:1:1, and KDO. Fraction III consisted of released monomers and salts. The LPS was highly phosphorylated (3.28% phosphorus in the core fraction). The thus characterized composition of the LPS O-chain seems to be unique for the pathovar phaseolicola of P. syringae, although many similarities exist to other pathovars as well as to other bacterial species.Abbreviations LPS lipopolysacchairdes - GC/MS combined gas liquid chromatography-mass spectrometry - HVE high voltage electrophoresis - KDO 2-keto-3-deoxyoctonic acid - PAGE polyacrylamide gel electrophoresis - SDS sodium dodecylsulfate P.s. pv. phaseolicola is termed P. phaseolicola in the text     

Pericentric inversion of chromosome 19 in three families

Summary Pericentric inversion of chromosome 19 has been found in several members of three unrelated families from a restricted geographical region. In one of the families, an additional pericentric inversion of chromosome 9 was observed. Reproductive problems, multiple abortions in two families and a neonatal death in the third, were present. A review of previously described cases is included, and the genetic risk connected with this type of rearrangement is also discussed.     

DR antigen expression on ovarian carcinoma cells does not correlate with their capacity to elicit an autologous proliferative response

Summary Expression of HLA-DR antigens by purified preparations of human ovarian carcinoma cells freshly isolated from surgical specimens was examined in parallel with the capacity of tumor cells to elicit a blastogenic response from autologous lymphocytes in mixed lymphocyte-tumor culture (MLTC) assay. Of 21 tumor preparations, 11 (52%) reacted with monoclonal antibodies 279 and/or 949 specific for a monomorphic determinant of HLA-DR antigens, with heterogeneous positivity, ranging between 30% and 95%. In this series of patients positive MLTC occurred in 8/21 individual experiments. The HLA-DR expression was proportionally similar in tumors giving positive MLTC (4/8=50%) and negative MLTC (7/13=53%). The lack of correlation between DR expression on tumor cells and stimulatory activity in autologous MLTC and the fact that DR-negative tumors could induce lymphocyte stimulation, support the hypothesis that blastogenesis occurs upon recognition of tumor-associated antigens, different from DR molecules, possibly tumor-specific antigens.     

Localization of the membrane-bound hydrogenase in Alcaligenes eutrophus by electron microscopic immunocytochemistry

Abstract The membrane-bound hydrogenase was localized in cells of Alcaligenes eutrophus by electron microscopic immunocytochemistry. Post-embedding labeling performed on ultrathin sections revealed that the enzyme was located predominantly (80%) at the cell periphery in autotrophically and heterotrophically grown bacteria harvested from the exponential phase of growth. In the stationary growth phase, however, only 50% of the enzyme was found at the cell periphery; the remaining 50% was distributed over the cytoplasm. The relative amount of electron microscopic label per cell as seen by application of the protein A—gold technique was higher in cells grown autotrophically as compared to cells grown heterotrophically on fructose. Derepression of the enzyme was followed electron microscopically in a substrate-shift experiment (growth on fructose, followed by a shift to glycerol). Major amounts of the enzyme appeared to undergo a reattachment to the cytoplasmic membrane under these conditions, starting with a reduced location of the enzyme in the cytoplasm and an accumulation in cell areas close to the cytoplasmic membrane. These findings indicate that the 'membrane-bound' hydrogenase (i.e., that material enriched as membrane-bound enzyme according to the appropriate activity test) is not, in fact, membrane bound or membrane integrated but membrane associated. It may or may not interact with the cytoplasmic face of the cytoplasmic membrane, depending on the growth phase and conditions.     

The Salmonella wien virulence plasmid pZM3 carries Tn1935, a multiresistance transposon containing a composite IS1936-kanamycin resistance element

Tn1935, a 23.5-kb transposon mediating resistance to ampicillin, kanamycin, mercury, spectinomycin, and sulfonamide was isolated from pZM3, an IncFIme virulence plasmid from Salmonella wien. Tn1935 possesses the entire sequence of Tn21 and contains two additional DNA segments of 0.95 and 2.7 kb carrying the ampicillin and kanamycin resistance genes, respectively. The latter is part of a composite element since it is flanked by two IS15-like insertion sequences (IS1936) in direct orientation. IS1936 is about 800 bp long and is closely related to IS15 delta, IS26, IS46, IS140, and IS176. Functional analysis of IS1936-mediated cointegrates shows that both insertion sequences are active and able to form cointegrates at the same frequency. Resolution of the cointegrates requires the presence of the host Rec system. The presence of the composite IS1936-element within Tn1935 supports the hypothesis that multidrug resistance transposons evolved by insertion of antibiotic determinants which are themselves transposable.     

Different lipid A types in lipopolysaccharides of phototrophic and related non-phototrophic bacteria

Lipid A analyses confirm not only the present taxa of the purple nonsulfur bacteria (formerly Rhodospirillaceae), but also phylogenetical relatedness of distinct phototrophic to distinct non-phototrophic bacteria, as was suggested by cataloguing 16S rRNA. For example, lipid A with ester-bound 3-OH-10:0 and the rare amide-linked 3-oxo-14:0 is common to the phototrophic Rhodobacter capsulatus and Rhodobacter sphaeroides and also to Paracoccus denitrificans and Thiobacillus versutus. 'Lipid ADAG' (lipid A with 2,3-diamino-D-glucose (DAG)) occurs in the phototrophic Rhodopseudomonas viridis and Rhodopseudomonas palustris and also in the related non-phototrophic species, e.g., Nitrobacter winogradskyi, Pseudomonas diminuta, or Thiobacillus ferrooxidans. The phylogenetically more coherent purple sulfur bacteria (Chromatiaceae) uniformly contain D-mannose in their phosphate-free lipid A. Among the green bacteria, only the Chlorobiaceae but not the likewise chlorosome-containing Chloroflexaceae contain lipopolysaccharide. Lipid ADAG from R. viridis is a structural analogue of a biosynthetic precursor (lipid X) of enterobacterial lipid A. Lipid A synthase from Salmonella accepts not only lipid X but also the synthetic di-N-acyl-2,3-diamino-D-glucose analogue as substrate (Raetz, C.R.H., unpublished results). More and more naturally occurring lipid A's with both, 2,3-diaminoglucose and glucosamine ('mixed' lipid A, with 2,3-diaminoglucose or glucosamine dominating) are being found. Newly recognized lipid A and lipid ADAG types might offer the possibility of differentially stimulating desired biological activities in animals without also having the undesired endotoxic activities. The non-toxic lipid A from Rhodopseudomonas viridis for example is able to stimulate prostaglandin secretion in peritoneal macrophages and can be used as an antagonist to the endotoxic shock caused by Salmonella lipopolysaccharide.     

Aspects of the reproductive biology of the bass, Dicentrarchus labrax L. I. An histological and histochemical study of oocyte development

Histological and histochemical studies of oocyte development in the bass, Dicentrarchus labrax L., showed that three types of inclusions are formed during vitellogenesis. Lipid yolk accumulates first as lipid droplets, followed by protein yolk in the form of discrete protein yolk granules. The third type of inclusion are the small cortical alveoli (intravesicular yolk/yolk vesicles, i.e.'carbohydrate yolk') which form in the peripheral cytoplasm after both the lipid and protein yolk have started to accumulate. While the protein yolk granules maintain their structural integrity through to maturation, forming a densely packed zone in the mid-outer cortex, the lipid yolk droplets continually coalesce and migrate centripetally, forming a prominent zone of large lipid droplets in the inner-mid cortex. From the histological study of oocyte development, a number of distinct developmental stages are delineated, while gross examination of the paired ovary revealed that, depending on its stage of development, it can be placed into one of seven maturity stages.