Smy2p Participates in COPII Vesicle Formation Through the Interaction with Sec23p/Sec24p Subcomplex

The coat protein complex II (COPII) is essential for vesicle formation from the endoplasmic reticulum (ER) and is composed of two heterodimeric subcomplexes, Sec23p/Sec24p and Sec13p/Sec31p, and the small guanosine triphosphatase Sar1p. In an effort to identify novel factors that may participate in COPII vesicle formation, we isolated SMY2, a yeast gene encoding a protein of unknown function, as a multicopy suppressor of the temperature-sensitive sec24-20 mutant. We found that even a low-copy expression of SMY2 was sufficient for the suppression of the sec24-20 phenotypes, and the chromosomal deletion of SMY2 led to a severe growth defect in the sec24-20 background. In addition, SMY2 exhibited genetic interactions with several other genes involved in the ER-to-Golgi transport. Subcellular fractionation analysis showed that Smy2p was a peripheral membrane protein fractionating together with COPII components. However, Smy2p was not loaded onto COPII vesicles generated in vitro. Interestingly, coimmunoprecipitation between Smy2p and the Sec23p/Sec24p subcomplex was specifically observed in sec23-1 and sec24-20 backgrounds, suggesting that this interaction was a prerequisite for the suppression of the sec24-20 phenotypes by overexpression of SMY2. We propose that Smy2p is located on the surface of the ER and facilitates COPII vesicle formation through the interaction with Sec23p/Sec24p subcomplex

Saccharomyces cerevisiae chitin biosynthesis activation by N-acetylchitooses depends on size and structure of chito-oligosaccharides

<p>Abstract</p> <p>Background</p> <p>To explore chitin synthesis initiation, the effect of addition of exogenous oligosaccharides on <it>in vitro </it>chitin synthesis was studied. Oligosaccharides of various natures and lengths were added to a chitin synthase assay performed on a <it>Saccharomyces cerevisiae </it>membrane fraction.</p> <p>Findings</p> <p><it>N</it>-acetylchito-tetra, -penta and -octaoses resulted in 11 to 25% [¹⁴C]-GlcNAc incorporation into [¹⁴C]-chitin, corresponding to an increase in the initial velocity. The activation appeared specific to <it>N</it>-acetylchitooses as it was not observed with oligosaccharides in other series, such as beta-(1,4), beta-(1,3) or alpha-(1,6) glucooligosaccharides.</p> <p>Conclusions</p> <p>The effect induced by the <it>N</it>-acetylchitooses was a saturable phenomenon and did not interfere with free GlcNAc and trypsin which are two known activators of yeast chitin synthase activity <it>in vitro</it>. The magnitude of the activation was dependent on both oligosaccharide concentration and oligosaccharide size.</p

Genome-scale modeling of the protein secretory machinery in yeast

The protein secretory machinery in Eukarya is involved in post-translational modification (PTMs) and sorting of the secretory and many transmembrane proteins. While the secretory machinery has been well-studied using classic reductionist approaches, a holistic view of its complex nature is lacking. Here, we present the first genome-scale model for the yeast secretory machinery which captures the knowledge generated through more than 50 years of research. The model is based on the concept of a Protein Specific Information Matrix (PSIM: characterized by seven PTMs features). An algorithm was developed which mimics secretory machinery and assigns each secretory protein to a particular secretory class that determines the set of PTMs and transport steps specific to each protein. Protein abundances were integrated with the model in order to gain system level estimation of the metabolic demands associated with the processing of each specific protein as well as a quantitative estimation of the activity of each component of the secretory machinery

What's new pussycat? A genealogy of animal celebrity

Animal celebrity is a human creation informing us about our socially constructed natural world. It is relational, expressive of cultural proclivities, political power plays and the quotidian everyday, as well as serious philosophical reflections on the meaning of being human. This article attempts to outline some key contours in the genealogy of animal celebrity, showing how popular culture, including fairground attractions, public relations, Hollywood movies, documentary films, zoo attractions, commercial sport and mediatised moral panics - particularly those accompanying scientific developments such as cloning - help to order, categorise and license aspects of human understanding and feelings. The nature of [animal] charisma and celebrity are explored with assistance from Jumbo the Elephant, Guy the Gorilla, Paul the clairvoyant octopus, Uggie the film star, Nénette the orang-utan and Dolly the sheep. It argues that the issue of what it is to be human lies beneath the celebritised surface or, as Donna Haraway noted, the issue 'of having to face oneself'

Dietary supplementation with hydrolyzed yeast and its effect on the performance, intestinal microbiota, and immune response of weaned piglets.

The objective of this study was to evaluate the effects of autolyzed yeast on performance, cecal microbiota, and leukogram of weaned piglets. A total of 96 piglets of commercial line weaned at 21-day-old were used. The experimental design was a randomized block design with four treatments (diets containing 0.0%, 0.3%, 0.6%, and 0.9% autolyzed yeast), eight replicates, and three animals per pen in order to evaluate daily weight gain, daily feed intake, and feed conversion in periods of 0 to 15, 0 to 26, and 0 to 36 days. Quadratic effects of autolyzed yeast inclusion were observed on the feed conversion from 0 to 15 days, on daily weight gain from 0 to 15 days, 0 to 26 days and, 0 to 36 days, indicating an autolyzed yeast optimal inclusion level between 0.4% and 0.5%. No effect from autolyzed yeast addition was observed on piglet daily feed intake, cecal microbiota, and leukogram; however, i.m. application of E. coli lipopolysaccharide reduced the values of total leukocytes and their fractions (neutrophils, eosinophils, lymphocytes, monocytes, and rods). Therefore, autolyzed yeast when provided at levels between 0.4% and 0.5% improved weaned piglets’ performance.info:eu-repo/semantics/publishedVersio

A multinational study exploring adolescent perception of school climate and mental health

School climate is a topic of increasing importance internationally. The current study investigated the established measurement invariance of an eight-factor school climate scale using a multinational sample of secondary students. School climate factor means across 14 international groups were compared and findings on the association between school climate factors and mental health were also investigated. Findings, from this study, illustrate several cross-national similarities regarding the ways in which secondary students perceive school climate and the influence of school climate on student mental health. These findings can support school psychologists’ efforts to identify strategies and supports that improve the school environment in areas that are most consistently related to student experiences, such as school safety and school connectedness. Implications, limitations, and future directions are discussed

The posthuman way of war

Recent interventions from a ‘posthumanist’ or ‘new materialist’ perspective have highlighted the embedded character of human systems within a ‘panarchy’ of human and non-human systems. This article brings attention to a very particular element of materiality, one with a profound significance for issues of security – relations between human and non-human animals in instances of conflict. It is an indication of the deeply human-centred character of both international relations and security studies that almost none of the central texts mention the very significant roles that non-human animals have in the conduct of war. We argue that the character of war would have been radically different but for the forced participation by an enormous range of non-human animals. Even though, with the improvements in transportation over the last century, non-human animals are less evident in the context of the movement of people and equipment, they still play a significant number of roles in the contemporary war-machines of wealthy countries. Drawing on literature from critical animal studies, sociology and memoirs, this article discusses the enormous variety of roles that non-human animals have played in the conduct of war, and examines the character of human–non-human animal relations in times of war

Polysaccharide synthesis in the dimorphic fungus Candida albicans

SIGLEAvailable from British Library Document Supply Centre- DSC:D42999/82 / BLDSC - British Library Document Supply CentreGBUnited Kingdo