Numerical Analysis of Astragalus cicer Microsymbionts

Thirty-seven rhizobium strains, isolated from root nodules of Astragalus cicer (L.) (cicer milkvetch) deriving from different geographic regions, were compared with the representative strains of the known rhizobial species and genera by numerical analysis of phenotypic characteristics. Our results indicated that Astragalus cicer rhizobia were related to the bacteria of Mesorhizobium species and formed two major phena. One phenon, localized on Mesorhizobium loti branch, contained strains from Poland. Another cluster, placed in the vicinity of M. tianshanense, M. mediterraneum, M. ciceri, and M. huakuii, comprised cicer milkvetch nodule isolates from Canada, Ukraine, and one strain from Poland. The relationship of Astragalus cicer microsymbionts to bacteria of the Mesorhizobium species was also supported by phage typing. Received: 10 February 2000 / Accepted: 8 March 2000     

Pediococci Residing on Plants

The pediococci residing on plants resemble the lactobacilli, but they differ from the streptococci in their limited distribution and low population level on plants. They are a subgroup within the genus Pediococcus which grow freely in neutral media and require neither NaCl nor CO(2). They are most readily recognized by the ability to initiate growth in liquid media, acidified to pH 5.0, which contain 1.5% sodium acetate. In stained preparations the cells occur singly and in pairs, short chains, and clusters. The occurrence of two-dimensional tetrads may be rare; this varies with the individual culture and with the culture medium. The terminal pH in 2% glucose broth varies from 3.6 to 4.3. Ability to initiate growth at 45 C, production of ammonia from arginine, dissimilation of malate, and fermentation of arabinose are confirmatory characteristics. The subgroup contains only two quite similar, but differentiable, species. P. acidilactici initiates growth at 50 C and produces catalase on heated blood medium but does not produce acid-sensitive catalase; a majority of the strains fail to initiate growth at 10 C and many fail to ferment maltose and lactose. P. pentosaceus initiates growth at 10 C but not at 50 C and produces acid-sensitive catalase; catalase production on heated blood medium is transient; a majority of the cultures ferment maltose, salicin, and trehalose. No carbohydrate serves reliably to differentiate between the species. The guanine plus cytosine ratio of P. pentosaceus deoxyribonucleic acid (DNA) was determined to be 35.1 +/- 1.2 and that of P. acidilactici DNA is 38.5 +/- 0.8.     

The role of motility in the efficiency of nodulation by Rhizobium meliloti

Tn5 mutants of Rhizobium meliloti L5.30 defective in motility (Mot^-) were isolated and compared to the parent with respect to the nodulation activity. Each of the mutants was able to generate normal nodules on the alfalfa (Medicago sativa) but had slightly delayed nodule formation. Coinoculation of lucerne with wild type Mot⁺ and Mot^- cells in the wide range of ratios resulted in nodules occupied in the majority by a motile strain suggesting that motility is a factor involved in the competition for nodule formation.     

Genetic instability in the <Emphasis Type="Italic">RAD51</Emphasis> and <Emphasis Type="Italic">BRCA1</Emphasis> regions in breast cancer

Breast cancer is the most prevalent cancer type in women. Accumulating evidence indicates that the fidelity of double-strand break repair in response to DNA damage is an important step in mammary neoplasias. The RAD51 and BRCA1 proteins are involved in the repair of double-strand DNA breaks by homologous recombination. In this study, we evaluated loss of heterozygosity (LOH) in the RAD51 and BRCA1 regions, and their association with breast cancer. The polymorphic markers D15S118, D15S214 and D15S1006 were the focus for RAD51, and D17S855 and D17S1323 for BRCA1. Genomic deletion detected by allelic loss varied according to the regions tested, and ranged from 29 to 46% of informative cases for the RAD51 region and from 38 to 42% of informative cases for the BRCA1 region. 25% of breast cancer cases displayed LOH for at least one studied marker in the RAD51 region exclusively. On the other hand, 31% of breast cancer cases manifested LOH for at least one microsatellite marker concomitantly in the RAD51 and BRCA1 regions. LOH in the RAD51 region, similarly as in the BRCA1 region, appeared to correlate with steroid receptor status. The obtained results indicate that alteration in the RAD51 region may contribute to the disturbances of DNA repair involving RAD51 and BRCA1 and thus enhance the risk of breast cancer development.     

Interaction of propranolol with model phospholipid membranes Monolayer,spin label and fluorescence spectroscopy studies

The interaction of propranolol with model phospholipid membranes was studied using various experimental techniques. The partition coefficient of propranolol in the negatively charged membranes of vesicles prepared from phosphatidylserine and phosphatidic acid was found to be more than 20-times higher than in neutral phosphatidylcholine membranes. Preferential interaction of propranolol with acidic phospholipid membranes was confirmed using the monolayer compression isotherm technique and the spin-labeling method. Phosphatidylserine monolayers were markedly expanded even at a relatively low drug concentration ($\text{5 · 10}{}^{\mathrm{?6}}$ M). In contrast, the effect of propranolol on phosphatidylcholine monolayers was much smaller, being detectable only at a higher concentration of the drug ($\text{1 · 10}{}^{\mathrm{?4}}$ M). Spin-labeling experiments show that propranolol exerts marked ordering effect on bilayers prepared from acidic phospholipids and does not change the order parameter of phosphatidylcholine membranes. The dependence of the propranolol fluorescence spectrum on the polarity of the solvent allowed us to identify the intercalation region of the drug in the membrane. The fluorophore moiety of propranolol was found to be localized in the lipid polar head groups region of the bilayer. The role of electrostatic and hydrophobic effects in propranolol-membrane interaction is discussed and the effect of propranolol on the ordering of phospholipid bilayers is compared with the effects of other anesthetic-like molecules.     

Diabetes-induced changes in the renal cortical proteome assessed with two-dimensional gel electrophoresis and mass spectrometry

To understand the spectrum of proteins affected by diabetes and to characterize molecular functions and biological processes they control, we analyzed the renal cortical proteome of db/db mice using 2-DE combined with MALDI-TOF, MALDI-TOF/TOF, and LC-MS/MS. This approach yielded 278 high confidence identifications whose expression levels were significantly increased or decreased >two-fold by diabetes, of which 170 mapped to gene identifiers representing 147 nonredundant proteins. Gene Ontology classification demonstrated that 80% of these proteins modulated physiological functions, 55% involved metabolism, approximately 25% involved carboxylic and organic acid metabolism, 14% involved biosynthesis or catabolism, and 12% involved fatty acid metabolism. Predominant molecular functions were catalytic (61%), oxidoreductase (20%), and transferase (17%) activities, and nucleotide and ATP binding (11-15%). Twenty eight percent of the proteins identified as significantly altered by diabetes were mitochondrial proteins. The top-ranked network described by Ingenuity Pathway Analysis indicated PPARalpha was the most common node of interaction for the numerous enzymes whose expression levels were influenced by diabetes. These differentially regulated proteins create a foundation for a systems biology exploration of molecular mechanisms underlying the pathophysiology of diabetic nephropathy.     

Emergence of Resistance to Fluconazole in <Emphasis Type="Italic">Candida albicans</Emphasis> Isolated From Vaginal Discharge

Purpose of Review

To provide information about the emergence of fluconazole resistance in Candida albicans isolated from vaginal discharge, in a global context, and to update the in vitro susceptibility profile of this species from Argentina.

Recent Findings

Vulvovaginal candidiasis is the second most common vaginal infection after vaginal bacteriosis. C. albicans remains the prevalent etiological yeast species, and despite antifungal treatment, the rate of recurrence remains high, which may be associated to antifungal resistance.

Summary

Data here presented were obtained from the study of C. albicans strains isolated from patients with clinical signs of vulvovaginal candidiasis from 1996 to 2017. Data obtained could represent the susceptibility profile of C. albicans strains circulating in Argentina and could be of potential usefulness to monitor and guide therapy, and also suggests the need for greater surveillance programs to detect fluconazole resistance over time.

     

Increased airway epithelial Na+ absorption produces cystic fibrosis-like lung disease in mice

Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene result in defective epithelial cAMP-dependent Cl(-) secretion and increased airway Na(+) absorption. The mechanistic links between these altered ion transport processes and the pathogenesis of cystic fibrosis lung disease, however, are unclear. To test the hypothesis that accelerated Na(+) transport alone can produce cystic fibrosis-like lung disease, we generated mice with airway-specific overexpression of epithelial Na(+) channels (ENaC). Here we show that increased airway Na(+) absorption in vivo caused airway surface liquid (ASL) volume depletion, increased mucus concentration, delayed mucus transport and mucus adhesion to airway surfaces. Defective mucus transport caused a severe spontaneous lung disease sharing features with cystic fibrosis, including mucus obstruction, goblet cell metaplasia, neutrophilic inflammation and poor bacterial clearance. We conclude that increasing airway Na(+) absorption initiates cystic fibrosis-like lung disease and produces a model for the study of the pathogenesis and therapy of this disease.     

Highly Asymmetric Cyclopropanation With Two Sulfinyl Auxiliaries as a Way to a Useful Synthetic Intermediate

The asymmetric cyclopropanation using double sulfinyl auxiliary gave bis‐sulfoxide with full diastereoselectivity and very high enantioselectivity. One of the sulfinyl substituents can be removed by sulfinyl metal exchange. Differentiation of sulfinyl substituents made it possible to assign the place of attack of the Grignard reagent. Chirality 27:816–819, 2015. © 2015 Wiley Periodicals, Inc.