Unconventional secretion of Acb1 is mediated by autophagosomes

Starving Dictyostelium discoideum cells secrete AcbA, an acyl coenzyme A–binding protein (ACBP) that lacks a conventional signal sequence for entering the endoplasmic reticulum (ER). Secretion of AcbA in D. discoideum requires the Golgi-associated protein GRASP. In this study, we report that starvation-induced secretion of Acb1, the Saccharomyces cerevisiae ACBP orthologue, also requires GRASP (Grh1). This highlights the conserved function of GRASP in unconventional secretion. Although genes required for ER to Golgi or Golgi to cell surface transport are not required for Acb1 secretion in yeast, this process involves autophagy genes and the plasma membrane t-SNARE, Sso1. Inhibiting transport to vacuoles does not affect Acb1 secretion. In sum, our experiments reveal a unique secretory pathway where autophagosomes containing Acb1 evade fusion with the vacuole to prevent cargo degradation. We propose that these autophagosome intermediates fuse with recycling endosomes instead to form multivesicular body carriers that then fuse with the plasma membrane to release cargo.     

Rapid and specific identification of nitrile hydratase (NHase)-encoding genes in soil samples by polymerase chain reaction

A polymerase chain reaction (PCR) protocol was developed for the specific detection of genes coding nitrile hydratase (NHase). Primer design was based on the highly conserved sequences found in the coding region of the alpha-subunit gene corresponding to the metal-binding site. Purified genomic DNA from bacterial strains or directly from soil can serve as the target for the PCR, thus affording a simple and rapid method for screening NHase genes. The primer pairs, NHCo1/NHCo2 and NHFe1/NHFe2 yield PCR products corresponding to a partial coding sequence of cobalt and iron NHase genes, respectively. Using the PCR method, both types of iron- and cobalt-NHase-encoding genes were detected in DNA from pure cultures and soil samples. Furthermore consensus primers allowed rapid cloning and expression of novel NHases in Escherichia coli.     

Effect of vertical sleeve gastrectomy in melanocortin receptor 4-deficient rats

Bariatric surgery is currently the most effective treatment for obesity. Vertical sleeve gastrectomy (VSG), a commonly applied bariatric procedure, involves surgically incising most of the volume of the stomach. In humans, partial loss of melanocortin receptor-4 (MC4R) activity is the most common monogenic correlate of obesity regardless of lifestyle. At present it is unclear whether genetic alteration of MC4R signaling modulates the beneficial effects of VSG. Following VSG, we analyzed body weight, food intake, glucose sensitivity, and macronutrient preference of wild-type and MC4R-deficient (Mc4r(+/-) and Mc4r(-/-)) rats compared with sham-operated controls. VSG reduced body weight and fat mass and improved glucose metabolism and also shifted preference toward carbohydrates and away from fat. All of this occurred independently of MC4R activity. In addition, MC4R was resequenced in 46 human subjects who underwent VSG. We observed common genetic variations in the coding sequence of MC4R in five subjects. However, none of those variations appeared to affect the outcome of VSG. Taken together, these data suggest that the beneficial effect of VSG on body weight and glucose metabolism is not mediated by alterations in MC4R activity.     

Systematic analysis of cell cycle effects of common drugs leads to the discovery of a suppressive interaction between gemfibrozil and fluoxetine

Screening chemical libraries to identify compounds that affect overall cell proliferation is common. However, in most cases, it is not known whether the compounds tested alter the timing of particular cell cycle transitions. Here, we evaluated an FDA-approved drug library to identify pharmaceuticals that alter cell cycle progression in yeast, using DNA content measurements by flow cytometry. This approach revealed strong cell cycle effects of several commonly used pharmaceuticals. We show that the antilipemic gemfibrozil delays initiation of DNA replication, while cells treated with the antidepressant fluoxetine severely delay progression through mitosis. Based on their effects on cell cycle progression, we also examined cell proliferation in the presence of both compounds. We discovered a strong suppressive interaction between gemfibrozil and fluoxetine. Combinations of interest among diverse pharmaceuticals are difficult to identify, due to the daunting number of possible combinations that must be evaluated. The novel interaction between gemfibrozil and fluoxetine suggests that identifying and combining drugs that show cell cycle effects might streamline identification of drug combinations with a pronounced impact on cell proliferation.     

Structure of bacterial communities along a hydrocarbon contamination gradient in a coastal sediment

The bacterial diversity of a chronically oil-polluted retention basin sediment located in the Berre lagoon (Etang-de-Berre, France) was investigated. This study combines chemical and molecular approaches in order to define how the in situ petroleum hydrocarbon contamination level affects the bacterial community structure of a subsurface sediment. Hydrocarbon content analysis clearly revealed a gradient of hydrocarbon contamination in both the water and the sediment following the basin periphery from the pollution input to the lagoon water. The nC17 and pristane concentrations suggested alkane biodegradation in the sediments. These results, combined with those of terminal-restriction fragment length polymorphism analysis of the 16S rRNA genes, indicated that bacterial community structure was obviously associated with the gradient of oil contamination. The analysis of bacterial community composition revealed dominance of bacteria related to the Proteobacteria phylum (Gamma-, Delta-, Alpha-, Epsilon- and Betaproteobacteria), Bacteroidetes and Verrucomicrobium groups and Spirochaetes, Actinobacteria and Cyanobacteria phyla. The adaptation of the bacterial community to oil contamination was not characterized by dominance of known oil-degrading bacteria, because a predominance of populations associated to the sulphur cycle was observed. The input station presented particular bacterial community composition associated with a low oil concentration in the sediment, indicating the adaptation of this community to the oil contamination.     

Anatomy, palynology and nutlet micromorphology of Turkish endemic Teucrium sandrasicum (Lamiaceae)

In this study, the anatomical features of the leaf and stem, besides the pollen and nutlet characteristics of Teucrium sandrasicum are investigated. T. sandrasicum, belonging to sect. Teucrium, is an endemic perennial herb growing on serpentine around Muğla province. The anatomical studies on T. sandrasicum revealed that the stem shares the general characteristics of the Labiatae family. The leaves clearly exhibit xeromorphy due to features such as the distribution of stomata on the lower surface (hipostomatic), the occurrence of guard cells below the epidermis (xeromorphic type), inrolled margins, thick cuticle layer, thick outer epidermal cell wall, a high density of trichomes and thick palisade layer of the mesophyll. The anatomical studies showed that the upper epidermal cells of the leaf include many spherocrystals. The pollen grains are prolate, medium in size, 3-colpate with verrucate ornamentation. The nutlets are ellipsoid with a reticulate-verrucate surface. The results have proven that T. sandrasicum is different from the other species of the sect. Teucrium because of the branched trichomes on the stem and the lack of eglandular trichomes on the nutlets.     

Removal of cadmium from aqueous solution by Nordmann fir (Abies nordmanniana (Stev.) Spach. Subsp. nordmanniana) leaves

The utility of Nordmann fir (Abies nordmanniana (Stev.) Spach. Subsp. nordmanniana) leaves from Eastern Black Sea region for the removal (sorption) of metal ions from aqueous solutions was investigated. For this, the optimum values of pH, time, metal concentration, leaf concentration, leaf particle size and adsorption capacity were determined. Also the recovery conditions of the metals from leaves were studied. Cd metal was selected because of its toxic properties. Freundlich isotherm model was used to describe the adsorption behaviour and the experimental results obtained for Cd(2+) adsorption, followed this model well. The utility of Nordmann fir leaves to remove toxic metals from aqueous solutions was proved. Hence, this study showed that the leaves of Nordmann fir can provide cheap source as biosorbents for toxic metal removal from natural or wastewaters.     

Antiviral activity of the volatile oils of Melissa officinalis L. against Herpes simplex virus type-2

Melissa officinalis L. (Lamiaceae) has been used in a variety of practical applications in medical science. Our objective in the current study was to determine the effects of the volatile oil components of M. officinalis on Herpes simplex virus type 2 (HSV-2) replication in HEp-2 cells. Four different concentrations (25, 50, 100, 150 and 200 μg/ml) of volatile oils were examined. Experiments were carried out using HEp-2 cells. M. officinalis volatile oil was found to be non-toxic to HEp-2 cells up to a concentration of 100 μg/ml. It was, however, found to be slightly toxic at a concentration over of 100 μg/ml. The antiviral activity of non-toxic concentrations against HSV-2 was tested. The replication of HSV-2 was inhibited, indicating that the M. officinalis L. extract contains an anti-HSV-2 substance.