Rhodobacter capsulatus strain BK5 possesses a membrane bound respiratory nitrate reductase rather than the periplasmic enzyme found in other strains

Rhodobacter capsulatus strain BK5 possesses a membrane bound respiratory nitrate reductase rather than the periplasmic enzyme found in other strains. The enzyme in strain BK5 is shown to be both functionally and structurally related to the nitrate reductase of Paracoccus denitrificans and Escherichia coli.Abbreviation TMAO trimethylamine-N-oxide     

High-resolution NMR studies of transmembrane cation transport in uremic patients

Cation transport in erythrocytes of some uremic patients is impaired. Most studies have focused on the defect of the erythrocyte Na+/K+ pump in these diseased states. Herein, this cation transport defect was studied by using nuclear magnetic resonance spectroscopy (NMR) which is a non-invasive method permitting study on living erythrocytes. Firstly, we verified that the Na+ transport defect in uremic erythrocytes was not due to non-specific causes such as membrane alteration or a modification of the intracellular metabolism. The proton relaxation data, determined using a paramagnetic doping method, are consistent with a lack of erythrocytic membrane damage in uremic patients. Also, 31P-NMR results showed that in our experimental conditions, uremic and normal erythrocytes exhibit similar variations of ATP level over time. Lastly, the use of anionic paramagnetic shift reagent in 23Na-NMR revealed a defect in the Na+/K+ pump of erythrocytes from uremic patients with high Nain concentration. This defect seems to be due to a reduced number of pump units and to the presence of an endogenous inhibitor in uremic plasma.     

Phosphatidic acid, phosphatidylinositol, phosphatidylserine and cardiolipin in the course of early embryonic development. Fatty acid composition and content in whole toad embryos and in mitochondrial fractions

The fatty acid composition and content of phosphatidylinositol, phosphatidylserine and phosphatidic acid have been studied during the early development of toad embryos. Acidic phospholipids have been analyzed in whole oocytes and embryos and in the following subcellular fractions: yolk platelets, mitochondria and microsomes. Also cardiolipin, a mitochondrial phospholipid, has been analyzed. Gastrula stage embryos have shown, mainly in the mitochondrial fraction, an increase in the content of phosphatidic acid, phosphatidylserine and phosphatidylinositol with respect to unfertilized oocytes. Changes in the distribution of acyl groups of phosphatidic acid have been detected when different subcellular fractions are compared. On the other hand, the phosphatidylserine composition remains unmodified. Arachidonate and stearate are the principal components of phosphatidylinositol. Cardiolipin shows the same composition up to gastrulation and linoleate comprises about 50% of the total acyl groups.     

Incorporation of (3H)-arachidonic acid into cattle retina lipids: high uptake in triacylglycerols, diacylglycerols, phosphatidylcholine and phosphatidylinositol.

The incubation of (³H)-arachidonic acid-prelabeled cattle retinas for 20 min in the presence of glucose under a gas phase of 5% carbon dioxide in oxygen showed uneven labeling in lipid classes. Total phospholipids, acylglycerides and free fatty acids contained 35, 37 and 31 per cent of the total radioactivity. In phosphatidylinositol and phosphatidylcholine almost 70% of the polar lipid (³H)-arachidonate was recovered. About 70% of the total fatty acid esterified in retina lipids was found in diacylglycerols, triacylglycerols, phosphatidylinositol and phosphatidylcholine. It is concluded that the cattle retina “in vitro” takes up free arachidonic acid and that this fatty acid is further unevenly acylated into lipids.The apolar fatty acyl residues of lipids display an independent turnover and their composition may be modified by acylation-deacylation reactions. In several cellular lipids, a differential turnover of the fatty acids as compared with other lipid moieties has been indicated, such as the case of phosphatidylinositol (1–3) and cardiolipin (4). The latter is enriched in the inner mitochondrial membrane where energy conservation processes take place and the former has been implicated in synaptic transmission (5) and related with a protein identified as the acetylcholine receptor (6). In brain phosphoinositides tetraenoic molecular species are by far the largest (2) and an active acylation-deacylation cycle of arachidonic acid occurs (7). However data regarding retina phosphoinositides composition and metabolism is limited to: fatty acid distribution (8), to some studies on the phosphodiester metabolism by ³²p (9) and to a study reporting that in frog rod outer segments and retina, polyphosphoinositides are undetectable (10). The purpose of the present investigation was to observe the (³H)-arachidonic acid labeling of acylglycerides and of phosphoglyceride classes of cattle retina.     

Understanding the function of the tumor microenvironment,and compounds from marine organisms for breast cancer therapy

The pathology and physiology of breast cancer(BC),including metastasis,and drug resistance,is driven by multiple signaling pathways in the tumor microenvironment(TME),which hamper antitumor immunity.Recently,long non-coding RNAs have been reported to mediate pathophysiological developments such as metastasis as well as immune suppression within the TME.Given the complex biology of BC,novel personalized therapeutic strategies that address its diverse pathophysiologies are needed to improve clinical outcomes.In this review,we describe the advances in the biology of breast neoplasia,including cellular and molecular biology,heterogeneity,and TME.We review the role of novel molecules such as long non-coding RNAs in the pathophysiology of BC.Finally,we provide an up-to-date overview of anticancer compounds extracted from marine microorganisms,crustaceans,and fishes and their synergistic effects in combination with other anticancer drugs.Marine compounds are a new discipline of research in BC and offer a wide range of anti-cancer effects that could be harnessed to target the various pathways involved in BC development,thus assisting current therapeutic regimens.     

Paleobiogeographic implications of the Middle Eocene ostracods from Cairo–Suez district,Egypt

The main targets of this paper are to examine the Middle Eocene ostracod assemblages collected from a succession exposed in the Cairo–Suez district, Egypt and to detect their paleobiogeographical implications. The studied succession is subdivided into two rock units: the Observatory and Qurn formations, in ascending order. The analysis of the ostracod assemblages led to the identification of 18 species, none of which is new. Three local biozones are established, Digmocythere ismaili - Xestoleberis kenawyi Assemblage Zone, Grinioneis moosi - Loxoconcha pseudopunctatella Assemblage Zone and Cativella qurnenis - Soudanella triangulata Assemblage Zone. The multivariate analyses indicate that there are three distinct bioprovinces, one of them represents the North Africa bioprovince, including Egypt, Libya, and Tunisia. The second bioprovince represents the Middle East, including Jordan and Israel. The third represents the West Africa bioprovince, including Senegal, Togo, Ivory Coast and Nigeria. Therefore, this deduction supports a migration of Eocene ostracods along the southern Tethys.     

The potential of antagonistic moroccan Streptomyces isolates for the biological control of damping‐off disease of pea (Pisum sativum L.) caused by Aphanomyces euteiches

Three hundred and fifty‐nine isolates of actinobacteria collected from different Moroccan soils were evaluated for their in vitro antimicrobial activity against the oomycete pathogen Aphanomyces euteiches, the causal agent of damping‐off of pea and other legumes. Eighty‐seven isolates (24%) had an inhibitory in vitro effect against A. euteiches. Fourteen bioactive isolates with the greatest inhibitory effect against A. euteiches and no inhibitory effect on plant beneficial rhizobia were tested for their ability to protect pea seeds and seedlings against the damping‐off disease using culture supernatants or spore suspensions as treatments. The two most protective isolates, OB21 and BA15, significantly reduced, compared to untreated control plants, damping‐off by 33% and 47%, respectively. The two bioactive isolates were classified as species of the genus Streptomyces based on 16S rDNA analysis and morphological and chemical characteristics.     

Profiling the CD8low phenotype, an alternative career choice for CD8 T cells during primary differentiation

A CD8+ T cell of naive phenotype has multiple career choices during its primary differentiation into an effector cell population. One of these career options is becoming a CD8low T cell. We have previously shown by in vitro studies that CD8low T cells have lost expression of CD8 surface protein and mRNA and are poorly cytolytic. In line with poor cytolytic function, CD8low T cells express low levels of perforin and granzyme B and C, mediators of the granule-exocytosis machinery. However, CD8low T cells express IFN-gamma and substantial amounts of IL-4, the signature cytokines of type 1 and type 2 T-cell polarization, respectively. Here, we argue that the CD8low phenotype is an alternative career choice for any naive CD8+ T cell during primary activation but that the probability of choosing this option is greatly enhanced by both IL-4 and strong activation conditions. CD8low T cells have downregulated CD8 alpha/beta heterodimers and no preferential CD8 alpha/alpha homodimer expression. As shown by anti-CD8 Ab blocking experiments, surface CD8 substantially contributes to the CD8 T cell's effector function (i.e. cytokine expression and cytolytic activity). The distinct effector profile of CD8low T cells gives an example of the complexity of different CD8 T cell careers during primary effector differentiation.