A coding variant in SR-BI (I179N) significantly increases atherosclerosis in mice

Human coding variants in scavenger receptor class B member 1 (SR-BI; gene name SCARB1) have recently been identified as being associated with plasma levels of HDL cholesterol. However, a link between coding variants and atherosclerosis has not yet been established. In this study we set out to examine the impact of a SR-BI coding variant in vivo. A mouse model with a coding variant in SR-BI (I179N), identified through a mutagenesis screen, was crossed with Ldlr ^?/? mice, and these mice were maintained on a Western-type diet to promote atherosclerosis. Mice showed 56 and 125 % increased atherosclerosis in female and male Ldlr ^?/? Scarb1 ^I179N mice, respectively, when compared to gender-matched Ldlr ^?/? control mice. As expected, HDL cholesteryl ester uptake was impaired in Ldlr ^?/? Scarb1 ^I179N mice compared to Ldlr ^–/– control mice, with a net effect of increased small and very small LDL cholesterol in Ldlr ^?/? Scarb1 ^I179N mice being the most probable cause of the observed increased atherosclerosis. Our data show that non-null coding variants in SR-BI can have a large significant impact on atherosclerosis, even if plasma lipid levels are not dramatically affected, and that human mutations in other candidate lipid genes could significantly impact atherosclerosis.     

Preferential secretion of collagen type 3 versus type 1 from adventitial fibroblasts stimulated by TGF-β/Smad3-treated medial smooth muscle cells

Restenosis, or arterial lumen re-narrowing, occurs in 30–50% of the patients undergoing angioplasty. Adaptive remodeling is the compensatory enlargement of the vessel size, and has been reported to prevent the deleterious effects of restenosis. Our previous studies have shown that elevated transforming growth factor (TGF-β) and its signaling protein Smad3 in the media layer induce adaptive remodeling of angioplastied rat carotid artery accompanying an increase of total collagen in the adventitia. In order to gain insights into a possible role of collagen in Smad3-induced adaptive remodeling, here we have investigated a mechanism of cell–cell communication between medial smooth muscle cells (SMCs) and adventitial fibroblasts in regulating the secretion of two major collagen subtypes. We have identified a preferential collagen-3 versus collagen-1 secretion by adventitial fibroblasts following stimulation by the conditioned medium from the TGF-β1-treated/Smad3-expressing medial smooth muscle cells (SMCs), which contained higher levels of CTGF and IGF2 as compared to control medium. Treating the TGF-β/Smad3-stimulated SMCs with an siRNA to either CTGF or IGF2 reversed the effect of conditioned media on preferential collagen-3 secretion from fibroblasts. Moreover, recombinant CTGF and IGF2 together stimulated adventitial fibroblasts to preferentially secrete collagen-3 versus collagen-1. This is the first study to identify a preferential secretion of collagen-3 versus collagen-1 from adventitial fibroblasts as a result of TGF-β/Smad3 stimulation of medial SMCs, and that CTGF and IGF2 function together to mediate this signaling communication between the two cell types.     

Contamination issues in a continuous ethanol production corn wet milling facility

Low ethanol yields and poor yeast viability were investigated at a continuous ethanol production corn wet milling facility. Using starch slurries and recycle streams from a commercial ethanol facility, laboratory hydrolysates were prepared by reproducing starch liquefaction and saccharification steps in the laboratory. Fermentations with hydrolysates prepared in the laboratory were compared with plant hydrolysates for final ethanol concentrations and total yeast counts. Fermentation controls were prepared using hydrolysates (plant and laboratory) that were not inoculated with yeast. Hydrolysates prepared in the laboratory resulted in higher final ethanol concentrations (15.8 % v/v) than plant hydrolysate (13.4 % v/v). Uninoculated controls resulted in ethanol production from both laboratory (12.2 % v/v) and plant hydrolysates (13.7 % v/v), indicating the presence of a contaminating microorganism. Yeast colony counts on cycloheximide and virginiamycin plates confirmed the presence of a contaminant. DNA sequencing and fingerprinting studies also indicated a number of dissimilar communities in samples obtained from fermentors, coolers, saccharification tanks, and thin stillage.     

Imaging heterogeneity of membrane and storage lipids in transgenic Camelina sativa seeds with altered fatty acid profiles

Engineering compositional changes in oilseeds is typically accomplished by introducing new enzymatic step(s) and/or by blocking or enhancing an existing enzymatic step(s) in a seed‐specific manner. However, in practice, the amounts of lipid species that accumulate in seeds are often different from what one would predict from enzyme expression levels, and these incongruences may be rooted in an incomplete understanding of the regulation of seed lipid metabolism at the cellular/tissue level. Here we show by mass spectrometry imaging approaches that triacylglycerols and their phospholipid precursors are distributed differently within cotyledons and the hypocotyl/radicle axis in embryos of the oilseed crop Camelina sativa, indicating tissue‐specific heterogeneity in triacylglycerol metabolism. Phosphatidylcholines and triacylglycerols enriched in linoleic acid (C18:2) were preferentially localized to the axis tissues, whereas lipid classes enriched in gadoleic acid (C20:1) were preferentially localized to the cotyledons. Manipulation of seed lipid compositions by heterologous over‐expression of an acyl–acyl carrier protein thioesterase, or by suppression of fatty acid desaturases and elongases, resulted in new overall seed storage lipid compositions with altered patterns of distribution of phospholipid and triacylglycerol in transgenic embryos. Our results reveal previously unknown differences in acyl lipid distribution in Camelina embryos, and suggest that this spatial heterogeneity may or may not be able to be changed effectively in transgenic seeds depending upon the targeted enzyme(s)/pathway(s). Further, these studies point to the importance of resolving the location of metabolites in addition to their quantities within plant tissues.     

A thermal hysteresis-producing xylomannan glycolipid antifreeze associated with cold tolerance is found in diverse taxa

The presence of large-molecular-mass, thermal hysteresis (TH)-producing antifreezes (e.g., antifreeze proteins) has been reported in numerous and diverse taxa, including representative species of fish, arthropods, plants, fungi, and bacteria. However, relatively few of these antifreeze molecules have been chemically characterized. We screened diverse species by subjecting their homogenates to ice-affinity purification and discovered the presence of a newly identified class of antifreeze, a xylomannan-based TH-producing glycolipid that was previously reported in one species of freeze-tolerant Alaskan beetle. We isolated xylomannan-based antifreeze glycolipids from one plant species, six insect species, and the first frog species to be shown to produce a large-molecular-mass antifreeze. ¹H NMR spectra of the ice-purified molecules isolated from these diverse freeze-tolerant and freeze-avoiding organisms were nearly identical, indicating that the chemical structures of the glycolipids were highly similar. Although the exact functions remain uncertain, it appears that antifreeze glycolipids play a role in cold tolerance.     

Development of a sensitive assay for the detection of Pseudoloma neurophilia in laboratory populations of the zebrafish Danio rerio

The zebrafish Danio rerio is an increasingly important biological model in many areas of research. Due to the potential for non-protocol-induced variation, diseases of zebrafish, especially those resulting in chronic, sub-lethal infections, are of great concern. The microsporidium Pseudoloma neurophilia is a common parasite of laboratory zebrafish. Current methods for detection of this parasite require lethal sampling of fish, which is often undesirable with poorly spawning mutant lines and small populations. We present here an improved molecular-based diagnostic assay using real-time polymerase chain reaction (PCR), and including sonication treatment prior to DNA extraction. Comparisons of several DNA extraction methods were performed to determine the method providing the maximum sensitivity. Sonication was found to be the most effective method for disrupting spores. Compared to previously published data on PCR-based assay using a dilution experiment, sensitivity is increased. This shows that our assay, which includes sonication, is capable of detecting parasite DNA at 1 log higher dilution than the conventional PCR-based assay, which does not include sonication. Furthermore, we demonstrate the application of this method to testing of water, eggs, and sperm, providing a potential non-lethal method for detection of this parasite in zebrafish colonies with a sensitivity of 10 spores 1(-1) of water, 2 spores per spiked egg sample, and 10 spores microl(-1) of spiked sperm sample.     

Quantitative trait loci for clinical mastitis on chromosomes 2, 6, 14 and 20 in Norwegian Red cattle

Mastitis is the most frequent and costly disease in dairy production and solutions leading to a reduction in the incidence of mastitis are highly demanded. Here a genome-wide association study was performed to identify polymorphisms affecting susceptibility to mastitis. Genotypes for 17 349 SNPs distributed across the 29 bovine autosomal chromosomes from a total of 2589 sires with 1 389 776 daughters with records on clinical mastitis were included in the analysis. Records of occurrence of clinical mastitis were divided into seven time periods in the first three lactations in order to identify quantitative trait loci affecting mastitis susceptibility in particular phases of lactation. The most convincing results from the association mapping were followed up and validated by a combined linkage disequilibrium and linkage analysis. The study revealed quantitative trait loci affecting occurrence of clinical mastitis in the periparturient period on chromosomes 2, 6 and 20 and a quantitative trait locus affecting occurrence of clinical mastitis in late lactation on chromosome 14. None of the quantitative trait loci for clinical mastitis detected in the study seemed to affect lactation average of somatic cell score. The SNPs highly associated with clinical mastitis lie near both the gene encoding interleukin 8 on chromosome 6 and the genes encoding the two interleukin 8 receptors on chromosome 2.     

Exploitation-related reef fish species richness depletion in the epicenter of marine biodiversity

The central Visayan region of the Philippines historically has the highest concentration of coral reef fishes than any other large marine area in the world. This well-supported biogeographic phenomenon is contradicted by recent transect observations on coral reefs that indicates that the Visayan region and the southern Philippine Sea region have the lowest species richness in the Philippines. The Visayan region has unusually low counts of species typically exploited in fisheries and the aquarium trade. This evidence, coupled with numerous reports of intense fishing and habitat degradation and subsequent species declines at local scales suggests that this exploitation is having a cumulative effect on the overall species richness of the Visayan region. Successes in Marine Protected Areas in this region in increasing species richness at local scales suggests that improved management of these protected areas coupled with much more intensive fisheries management will be key to reviving a healthy biodiversity in the Visayas.     

Production of 5-hydroxymethylfurfural from glucose catalyzed by hydroxyapatite supported chromium chloride

Production of 5-hydroxymethylfurfural (HMF) from glucose was studied in ionic liquids in the presence of hydroxyapatite supported chromium chloride (Cr-HAP) using oil-bath heating and microwave irradiation (MI). Compared with oil-bath heating, the MI way obviously increased HMF yield and reduced the reaction time from days to several minutes. A maximum HMF yield of 40% was obtained from the dehydration of glucose under MI in 2.5 min. This method is potential as an energy-efficient and cost-effective approach for the conversion of biomass into platform chemicals.