Insulin and hypertonicity recruit GLUT4 to the plasma membrane of muscle cells by using N-ethylmaleimide-sensitive factor-dependent SNARE mechanisms but different v-SNAREs: role of TI-VAMP

Insulin and hypertonicity each increase the content of GLUT4 glucose transporters at the surface of muscle cells. Insulin enhances GLUT4 exocytosis without diminishing its endocytosis. The insulin but not the hypertonicity response is reduced by tetanus neurotoxin, which cleaves vesicle-associated membrane protein (VAMP)2 and VAMP3, and is rescued upon introducing tetanus neurotoxin-resistant VAMP2. Here, we show that hypertonicity enhances GLUT4 recycling, compounding its previously shown ability to reduce GLUT4 endocytosis. To examine whether the canonical soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) mechanism is required for the plasma membrane fusion of the tetanus neurotoxin-insensitive GLUT4 vesicles, L6 myoblasts stably expressing myc-tagged GLUT4 (GLUT4myc) were transiently transfected with dominant negative N-ethylmaleimide-sensitive factor (NSF) (DN-NSF) or small-interfering RNA to tetanus neurotoxin-insensitive VAMP (TI-VAMP siRNA). Both strategies markedly reduced the basal level of surface GLUT4myc and the surface gain of GLUT4myc in response to hypertonicity. The insulin effect was abolished by DN-NSF, but only partly reduced by TI-VAMP siRNA. We propose that insulin and hypertonicity recruit GLUT4myc from partly overlapping, but distinct sources defined by VAMP2 and TI-VAMP, respectively.     

Visible Light Induces Melanogenesis in Human Skin through a Photoadaptive Response

Visible light (400–700 nm) lies outside of the spectral range of what photobiologists define as deleterious radiation and as a result few studies have studied the effects of visible light range of wavelengths on skin. This oversight is important considering that during outdoors activities skin is exposed to the full solar spectrum, including visible light, and to multiple exposures at different times and doses. Although the contribution of the UV component of sunlight to skin damage has been established, few studies have examined the effects of non-UV solar radiation on skin physiology in terms of inflammation, and limited information is available regarding the role of visible light on pigmentation. The purpose of this study was to determine the effect of visible light on the pro-pigmentation pathways and melanin formation in skin. Exposure to visible light in ex-vivo and clinical studies demonstrated an induction of pigmentation in skin by visible light. Results showed that a single exposure to visible light induced very little pigmentation whereas multiple exposures with visible light resulted in darker and sustained pigmentation. These findings have potential implications on the management of photo-aggravated pigmentary disorders, the proper use of sunscreens, and the treatment of depigmented lesions.     

Functional characterization of two type-1 diacylglycerol acyltransferase (DGAT1) genes from rice (Oryza sativa) embryo restoring the triacylglycerol accumulation in yeast

Plant Molecular Biology - Two OsDGAT1 genes showed the ability to restore TAG and LB synthesis in yeast H1246. Alterations in the N-terminal region of OsDGAT1-1 gene revealed its regulatory role in...     

Cefotaxime prevents microbial contamination and improves microspore embryogenesis in wheat and triticale

Key message

Cefotaxime (100 mg/l) mitigate occasional gram negative bacterial contamination in wheat and triticale microspore culture and most importantly it increases cell growth and green plant production.

Abstract

Isolated microspore culture is a promising option to rapidly fix the product of meiotic recombination of F₁ hybrids, in the process of varietal development. Clean culture and high embryogenesis rate are essential to commercial triticale and wheat microspore cultures. So, this study investigated (1) contaminants from isolated microspores cultures, (2) two antibiotics to control bacterial growth, and (3) the contribution of antibiotics to increased microspore-derived embryo-like structures (ELS), green and albino plants. Five species of bacteria were identified in contaminated cultures (Erwinia aphidicola, Pantoea agglomerans, Pseudomonas sp., Staphylococcus epidermis and Staphylococcus warneri) using fatty acid analysis and 16S ribosomal RNA sequences analysis, and yeast. Antibacterial susceptibility test using Cefotaxime and Vancomycin resulted in strong inhibition of 24 bacterial isolates, using Cefotaxime at 100 mg/l, but not Pseudomonas sp. Other antibiotic treatments inhibited bacterial growth at least partially. Microspore induction medium supplemented with the same antibiotics treatments resulted in successful microspore embryogenesis and green plant production. Antibiotic treatments were first tested in triticale and then validated in wheat cultivars AC Carberry and AC Andrew. Induction medium supplemented with Cefotaxime at 50 and 100 mg/l substantially increased the formation of ELS and green plants in triticale and wheat, respectively. Incidentally, it also affected the occurrence of albinism in all genotypes. Our results demonstrated dual purpose of Cefotaxime for isolated microspore culture, most importantly it increases cell growth and success of microspore cultures in triticale and wheat genotypes, but would also prevent accidental loss of cultures with most common bacterial contaminants.     

Insights using a molecular approach into the life cycle of a tapeworm infecting great white sharks

The great white shark Carcharodon carcharias Linnaeus, 1758 is a versatile and fierce predator (and responsible for many shark attacks on humans). This apex predator feeds on a wide range of organisms including teleosts, other elasmobranchs, cephalopods, pinnipeds, and cetaceans. Although much is known about its diet, no trophic links have been empirically identified as being involved in the transmission of its tapeworm parasites. Recently, the use of molecular tools combined with phylogenetics has proven useful to identify larval and immature stages of marine tapeworms; utilization of the technique has been increasing rapidly. However, the usefulness of this approach remains limited by the availability of molecular data. Here, I employed gene sequence data from the D2 region of the large subunit of ribosomal DNA to link adults of the tapeworm Clistobothrium carcharodoni Dailey and Vogelbein, 1990 (Cestoda: Tetraphyllidea) to larvae for which sequence data for this gene are available. The sequences from the adult tapeworms were genetically identical (0% sequence divergence) to those available on GenBank for "SP" 'small' Scolex pleuronectis recovered from the striped dolphin (Stenella coeruleoalba) and Risso's dolphin (Grampus griseus). This study is the first to provide empirical evidence linking the trophic interaction between great white sharks and cetaceans as a definitive route for the successful transmission of a tetraphyllidean tapeworm. Using the intensity of infection data from this shark and from cetaceans as proxies for the extent of predation, I estimate that this individual shark would have consumed between 9 to 83 G. griseus , fresh, dead, or both, in its lifetime.     

On the re-isolation and taxonomic study of Candida viswanathii Viswanathan et Randhawa 1959

Summary A detailed taxonomic study of a new isolate ofCandida viswanathii from sputum is reported.     

On the occurrence of two new species of Trichophyton in Indian soils

Summary Two new species ofTrichophyton, T. indicum andT. evolceanui, isolated from soil in India by the hair baiting technique, are described.T. indicum is characterized by its flat colony and delicately roughened microconidia. It is common and widely distributed in soil in India. T. evolceanui can be distinguished fromT. indicum by its heaped and folded colony on tomato juice agar and its echinulate and obovate microconidia which are consistently wider than those ofT. indicum on the various culture media tested.T. evolceanui also differs fromT. indicum in producing perforating organs on hair in vitro soil culture. It has restricted occurrence in Indian soils.     

Plant Cell Wall Matrix Polysaccharide Biosynthesis

The wall of an expanding plant cell consists primarily of cellulose microfibrils embedded in a matrix of hemicellulosic and pectic polysaccharides along with small amounts of structural and enzymatic proteins. Matrix polysaccharides are synthesized in the Golgi and exported to the cell wall by exocytosis, where they intercalate among cellulose microfibrils, which are made at the plasma membrane and directly deposited into the cell wall. Involvement of Golgi glucan synthesis in auxin-induced cell expansion has long been recognized; however, only recently have the genes corresponding to glucan synthases been identified. Biochemical purification was unsuccessful because of the labile nature and very low abundance of these enzymes. Mutational genetics also proved fruitless. Expression of candidate genes identified through gene expression profiling or comparative genomics in heterologous systems followed by functional characterization has been relatively successful. Several genes from the cellulose synthase-like （Csl） family have been found to be involved in the synthesis of various hemicellulosic glycans. The usefulness of this approach, however, is limited to those enzymes that probably do not form complexes consisting of unrelated proteins. Nonconventional approaches will continue to incrementally unravel the mechanisms of Golgi polysaccharide biosynthesis.     

Synthesis of novel anilinoquinolines as c-fms inhibitors

A novel series of potent substituted anilinoquinolines were discovered as c-fms inhibitors. The potency could be manipulated upon modification of the C4 aniline and C7 aryl functionality. Pharmacokinetic analysis identified a metabolically stable analog suitable for further investigative work.