Genetic Pleiotropy for Resting Metabolic Rate with Fat-Free Mass and Fat Mass: The Québec Family Study

Shared genetic and familial environmental causes for the associations among resting metabolic rate (RMR), fat-free mass (FFM), and fat mass (FM) were investigated in families participating in phase 2 of the Québec Family Study. A multivariate familial correlation model assessing the pattern of significant cross-trait correlations between family members (e.g., RMR in parents with FFM in offspring) was used to infer the etiology of the associations. For each of FM and FFM with RMR, significant sibling, parent-offspring, and intraindividual cross-trait correlations suggest the associations are familial. Furthermore, the lack of significant spouse cross-trait correlations suggests that the familial aggregation is primarily genetic. Bivariate heritability estimates suggest that as much as 45% to 50% of the shared variance between FFM and RMR may be genetic, and as much as 28% to 34% for FM and RMR. This study supports the notion that the gene(s) affecting each of FFM and FM also influence the RMR. Moreover, the lack of any familial associations between FFM and FM suggests that the effects of each body size component on RMR are independent, i.e., more than one genetic source on the RMR-body size association. The possibility that RMR is an oligogenic trait (i.e., more than one underlying genetic etiology) should be further investigated using more complex multivariate segregation methods until specific genes can be tested.     

Novel method for purification of staphylococcal enterotoxin A

A novel single-step procedure for the purification of staphylococcal enterotoxin A (SEA), namely, dye ligand affinity chromatography with the triazine dye Red A, was developed. SEA purified by this method produced a single band when subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The yield from 5 liters of culture supernatant was 0.113 g, corresponding to an overall yield of 55%. In some instances, purification of SEA from culture supernatants by dye ligand affinity chromatography produced two enterotoxin peaks that could be eluted from the column with 300 and 500 mM phosphate buffer (pH 6.8). Enterotoxin from these peaks produced a single band when subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, but multiple bands were observed on isoelectric focusing gels. This method of purification represents a significant improvement in time, yields, and purity of enterotoxin over previously published purification methods.     

<Emphasis Type="Italic">Heteroconium chaetospira</Emphasis>, a dark septate root endophyte allied to the Herpotrichiellaceae (Chaetothyriales) obtained from some forest soil samples in Canada using bait plants

During an extended search in Western Canada for fungal root endophytes useful as biocontrol agents against soil-borne pathogens, we isolated Heteroconium chaetospira, as well as Phialocephala fortinii or similar taxa, from seven samples of forest soil using herbaceous seedlings of four different species (i.e., barley, Chinese cabbage, eggplant, and melon) as bait plants. Our results support a previous observation that eggplant is a particularly effective species for baiting H. chaetospira from soil and confirm the ability of this fungus to grow as an endophyte in the roots of axenically reared host plants. Cultural characters show that this species is similar to P. fortinii and other melanized fungi in the dark septate endophyte (DSE) group (e.g., Leptodontidium orchidicola, P. sphaeroides, and Cadophora finlandica) in that it produces darkly pigmented colonies on agar media. Heteroconium chaetospira differs from P. fortinii and other melanized members of the Leotiomycetes in the DSE group in that its conidia are fusiform and develop in blastic acropetal chains. Heteroconium chaetospira is phylogenetically distant from most DSE taxa because DNA sequences for the nuclear small subunit (SSU) ribosomal RNA gene (rDNA) indicate that the taxon is affiliated with the Herpotrichiellaceae of the Chaetothyriales rather than with the Leotiomycetes.     

Puccinia chunjii, a close relative of the cereal stem rusts revealed by molecular phylogeny and morphological study

A rust specimen with macroscopic similarities to the cereal stem rusts was collected on Elymus sp. from Gansu province, China. Phylogenetic analyses of ITS and COI DNA sequences indicated the fungus was closely related but distinct as a strongly supported sister taxon to the Puccinia graminis species complex. Microscopic examination revealed diagnostic teliospore characteristics, differentiating it from P. graminis and other morphologically similar rusts. Herein, we designate a name for this new lineage, Puccinia chunjii sp. nov.     

Influence of interactions on water and aroma permeabilities of ι-carrageenan–oleic acid–beeswax films used for flavour encapsulation

The objective of this work is to investigate the water and aroma barrier properties of films obtained from ι-carrageenan containing glycerol and lipids mixtures of oleic acid (OA) and beeswax (BW) used for encapsulation of active compounds. Water vapor permeability (WVP) is greatly influenced by lipid composition, encapsulated aroma compound and also relative humidity. WVP decreases when films contain encapsulated aroma compound but increases when the moisture content in the films increases. When oleic acid was the main compound of lipid phase, the plasticizing effect of water revealed through water permeability is less marked. The results of ethyl acetate, ethyl butyrate, ethyl hexanoate, 2-hexanone, 1-hexanol and cis-3-hexenol permeabilities reveal that physicochemical interactions between aroma compounds-hydrocolloid and aroma compound-lipid induce structural changes and modify their permeability. This work gives evidence of the ability of ι-carrageenan–OA–BW films to protect encapsulated aroma compound and its influence in barrier properties.     

The preservation of ultrastructure in saturated phosphatidyl cholines by tannic acid in model systems and type II pneumocytes

The preservation for electron microscopy of saturated phospholipids in general, and phosphatidyl choline (PC)in particular, remains and unsolved problem since OsO(4) and glutaraldehyde are incapable of interacting with PC directly. However, by introducing tannic acid preceding osmication, we were able to demonstrate highly ordered, preserved lamellar structures in model experiments with saturated PC, and in vivo experiments type II pneumocytes of lung tissue. The secretory bodies of the latter are known to contain a high proportion of these saturated phospholipids. In both cases, the repeating periodicity approximated 45 A. It was determined that tannic acid interacts with the choline component of PC to form a "complex," which then could be stabilized by treatment with OsO(4). In the absence of osmication, the PC-tannic acid complex acid did not survive conventional dehydration techniques, but osmication permitted conventional Epon embedment. Sphingomyelin (SPH), which contains choline, behaved similarly in model experiments. But there was no evidence of a comparable reaction with tannic acid using phosphatidyl ethanolamine (PEA), phosphatidyl serine (PS), or phosphstidy inositol (PI). Chemical studies indicted a high pH dependency for the formation of the PC- tannic acid complex. Also, experiments demonstrated its dissociation in various organic solvents. Sharp delineation and great contrast of the polar zones in the ordered lamellar structures was achieved by additional staining with lead citrate thus leading to the conclusion that tannic acid serves as a multivalent agent, capable of simultaneous interaction with saturated PC, OsO(4), and lead citrate stains.     

Cyclic amp-induced morphological transformation of cells infected by temperature-sensitive mouse sarcoma virus: Expression of transformation-associated markers

Normal rat kidney (NRK) cells infected with a temperature-sensitive (ts) mutant of mouse sarcoma virus (NRK [MSV-1b]) express the transformed phenotype when grown under permissive conditions, but acquire the normal phenotype when grown under restrictive conditions. Addition of 3', 5' cyclic adenosine monophosphate (cAMP) to NRK (MSV-1b) cells grown at the restrictive temperature results in morphological transformation. To determine whether other markers associated with the transformed phenotype were coordinately expressed after cAMP exposure, concanavalin A (Con A) agglutinability, hexose transport rate, and incorporation of radioactively labeled fucose into fucolipid III and fucolipid IV (FL III and FL IV ) of the cells were examined. NRK cells transformed by wild-type MSV or NRK(MSV- 1b) grown under permissive conditions were agglutinated by low concentrations of Con A and exhibited relatively high maximal agglutination levels which were specifically inhibited by α-methyl-D-mannoside. In contrast, NRK (MSV-1b) cells grown under restrictive conditions were weakly agglutinated by Con A and exhibited reduced maximal agglutination levels, similar to uninfected NRK cells. Treatment of NRK (MSV-1b) cells at the restrictive temperature with cAMP resulted in morphological transformation and a change in the pattern of incorporation of labeled fucose inot FL III and FL IV to one comparable to that of NRK (MSV-1b) cells at the permissive temperature or to NRK cells transformed by wild-type MSV. In contrast, cAMP treatment resulted in no increase in Con A agglutinability or 2 deoxy-D- [(3)H]glucose transport relative to mock treated cultures. The results demonstrate that cAMP-induced morphological transformation and altered fucolipid composition of NRK (MSV-1b) cells are not correlated with alterations in hexose transport rate or Con A agglutinability.