Cantharellus pleurotoides, a new and unusual basidiomycete from Guyana

Cantharellus pleurotoides sp. nov. (Cantharellaceae, Cantharellales, Basidiomycota) is described from the Pakaraima Mountains of Guyana, occurring in rainforests dominated by ectomycorrhizal Dicymbe spp. (Caesalpiniaceae). This fungus is singular among Cantharellus species described worldwide in possessing a pleurotoid basidioma. Macromorphological, micromorphological, and habitat data are provided for the new species.     

Surfactin and fengycin contribute to the protection of a Bacillus subtilis strain against grape downy mildew by both direct effect and defence stimulation

Bacillus subtilis GLB191 (hereafter GLB191) is an efficient biological control agent against the biotrophic oomycete Plasmopara viticola, the causal agent of grapevine downy mildew. In this study, we show that GLB191 supernatant is also highly active against downy mildew and that the activity results from both direct effect against the pathogen and stimulation of the plant defences (induction of defence gene expression and callose production). High-performance thin-layer chromatography analysis revealed the presence of the cyclic lipopeptides fengycin and surfactin in the supernatant. Mutants affected in the production of fengycin and/or surfactin were thus obtained and allowed us to show that both surfactin and fengycin contribute to the double activity of GLB191 supernatant against downy mildew. Altogether, this study suggests that GLB191 supernatant could be used as a new biocontrol product against grapevine downy mildew.     

Hepatic Xbp1 Gene Deletion Promotes Endoplasmic Reticulum Stress-induced Liver Injury and Apoptosis

Endoplasmic reticulum (ER) stress activates the unfolded protein response (UPR), a highly conserved signaling cascade that functions to alleviate stress and promote cell survival. If, however, the cell is unable to adapt and restore homeostasis, then the UPR activates pathways that promote apoptotic cell death. The molecular mechanisms governing the critical transition from adaptation and survival to initiation of apoptosis remain poorly understood. We aim to determine the role of hepatic Xbp1, a key mediator of the UPR, in controlling the adaptive response to ER stress in the liver. Liver-specific Xbp1 knockout mice (Xbp1^LKO) and Xbp1^fl/fl control mice were subjected to varying levels and durations of pharmacologic ER stress. Xbp1^LKO and Xbp1^fl/fl mice showed robust and equal activation of the UPR acutely after induction of ER stress. By 24 h, Xbp1^fl/fl controls showed complete resolution of UPR activation and no liver injury, indicating successful adaptation to the stress. Conversely, Xbp1^LKO mice showed ongoing UPR activation associated with progressive liver injury, apoptosis, and, ultimately, fibrosis by day 7 after induction of ER stress. These data indicate that hepatic XBP1 controls the adaptive response of the UPR and is critical to restoring homeostasis in the liver in response to ER stress.     

Distinct intracellular vesicle transport mechanisms are selectively modified by spastin and spastin mutations

Spastin is a microtubule severing ATPase that regulates intracellular and axonal transport of vesicles. Intracellular vesicle trafficking was analyzed in differentiated SH‐SY5Y‐neuroblastoma cells, transfected with spastin wild‐type and three spastin mutations (ΔN, K388R, S44L) to investigate spastin‐mediated effects on the velocity of vesicles, stained with LysoTracker Red®. The vesicle velocity varied considerably between mutations and detailed analysis revealed up to five distinct velocity classes. Microtubule severing by overexpressed wild‐type spastin caused reduced vesicle velocity. S44L and ΔN mutations, which were functionally impaired, showed similar velocities as control cells. K388R‐transfected cells exhibited an intermediate velocity profile. The results support the idea that spastin mutations not only alter axonal transport, but in addition regulate intracellular trafficking in the cell soma as well. J. Cell. Physiol. 226: 362–368, 2011. © 2010 Wiley‐Liss, Inc.     

Manufacturing procedures and microbiological aspects ofParakari, a novel fermented beverage of the wapisiana amerindians of Guyana

The alcoholic beverageparakari, a unique fermentation product of cassava (Manihot esculenta Crantz) by the Wapisiana of Guyana, involves the use of a starch-hydrolyzing (amylolytic) mold (Rhizopus sp., Mucoraceae, Zygomycota) followed by a solid-state ethanol fermentation. A detailed study was made of theparakari manufacturing process in the Wapisiana village of Aishalton, South Rupununi, Guyana. Thirty steps were involved inparakari manufacture and these exhibited a high degree of sophistication, including the use of specific cassava varieties, control of culture temperature, and boosting of inoculum potential with purified starch additives. During the fermentation process, changes in glucose content, pH, taste, smell, and culture characteristics were reported for the fermenting mash.Parakari is the only known example of an indigenous New World fermentation that utilizes an amylolytic mold. Manufacture ofparakari is analogous to similar dual fermentations of the Orient, yet independently derived.     

Novel insights into biosynthesis and uptake of rhamnolipids and their precursors

Applied Microbiology and Biotechnology - The human pathogenic bacterium Pseudomonas aeruginosa produces rhamnolipids, glycolipids with functions for bacterial motility, biofilm formation, and...     

Effect of water clarity on the distribution of marine birds in nearshore waters of Monterey Bay, California

ABSTRACT.   The distribution of marine birds relative to water clarity was examined in the nearshore waters of Monterey Bay, California. I conducted nine at-sea surveys in 1999 and 2000 and simultaneously recorded water clarity and the density of five taxa of marine birds. Among plunge-divers, Forster's Terns ( Sterna forsteri ) occurred more frequently than expected over turbid water (<2.5 m Secchi depth) and, among pursuit-diving species, Brandt's Cormorants ( Phalacrocorax penicillatus ) occurred most often in the clearest water available (>5 m Secchi depth). Turbidity in Monterey Bay may be caused by suspended organic matter, including phytoplankton, during summer and fall. Forster's Tern may prefer such areas because small fish are likely to occur near this potential food source. Brandt's Cormorants probably rely on vision to catch fish near the bottom and turbid water may reduce available light and limit visual acuity. The distribution of Brown Pelicans (Pelecanus occidentalis ), Western/Clark's Grebes (Aechmophorus occidentalis/clarkii ), and Marbled Murrelets ( Brachyramphus marmoratus ) did not appear to be influenced by turbidity levels, indicating that some seabirds use marine habitats with a wide range of water clarities.