Virus-induced Abl and Fyn kinase signals permit coxsackievirus entry through epithelial tight junctions

Group B coxsackieviruses (CVBs) must cross the epithelium as they initiate infection, but the mechanism by which this occurs remains uncertain. The coxsackievirus and adenovirus receptor (CAR) is a component of the tight junction and is inaccessible to virus approaching from the apical surface. Many CVBs also interact with the GPI-anchored protein decay-accelerating factor (DAF). Here, we report that virus attachment to DAF on the apical cell surface activates Abl kinase, triggering Rac-dependent actin rearrangements that permit virus movement to the tight junction. Within the junction, interaction with CAR promotes conformational changes in the virus capsid that are essential for virus entry and release of viral RNA. Interaction with DAF also activates Fyn kinase, an event that is required for the phosphorylation of caveolin and transport of virus into the cell within caveolar vesicles. CVBs thus exploit DAF-mediated signaling pathways to surmount the epithelial barrier.     

Trichloroethene Biodegradation Potential in Wetland Soils and Paleowetland Sediments

Trichloroethene (TCE) plumes extend north-northeast toward the Ohio River from the Paducah Gaseous Diffusion Plant (PGDP), a Superfund site in the Gulf Coastal Plain of western Kentucky. Wetlands in the floodplain are in the paths of these plumes, and on-site contamination has migrated downward from the Regional Gravel Aquifer (RGA) into the upper McNairy Formation, which overlies a bedrock aquifer. Intrinsic biodegradation in these two environments at the margins of the RGA could limit further contaminant migration and ecosystem or water-quality degradation. To assess cometabolic biodegradation potential in these uncontaminated environments, we attempted to culture and enumerate methanogens, sulfate- and Fe(III)-reducers, and methanotrophs, which have been implicated elsewhere as TCE degraders. Soil samples were collected at three wetland sites in the floodplain. McNairy sediments were collected beneath one of the suspected source areas at PGDP. Methanogens, sulfate reducers, and methanotrophs were abundant in wetland soils, with populations generally decreasing with depth. Methanogens were the only group cultured from McNairy sediments, and they showed little activity compared with wetland methanogen cultures. TCE loss in methanogenic batch cultures by chemoautotrophic and acetoclastic methanogens was monitored, but no significant degradation was observed.     

Structural basis for the anticoagulant activity of heparin. 1. Relationship to the number of charged groups.

This study was undertaken to provide further information concerning the chemical heterogeneity of heparins and the relationships between the anticoagulant activity (USP assay) and the anionic density of the heparin. A sample of commercial heparin was fractionated into 13 fractions by sequential extraction in a two-phase system of 1-butanol-aqueous NaCl containing excess hexadecylpyridinium chloride. The anionic density distribution was characterized by the fractional distribution of uronate among the fractions. The fractions were characterized by several molar ratios of constituents, molecular weight, charge density, and anticoagulant activity in recalcified sheep plasma. The heparin was broadly distributed among the last 10 fractions; the first three contained impurities which were completely separated from the heparin fractions. The heparin fractions differ systematically in anionic density but are of substantially the same molecular weight. Anticoagulant activity increased markedly with anionic density, ranging from 81 units/mg for the heparin fraction with the lowest anionic density up to a high of 243 units/mg. The relationship between anticoagulant activity and either anionic density or its square is nonlinear. However, in the latter case an initial linear relationship was observed for anticoagulant activities of less than 200 units/mg.     

Screenhouse and Field Persistence of Nonpathogenic Endophytic Fusarium oxysporum in Musa Tissue Culture Plants

Two major biotic constraints to highland cooking banana (Musa spp., genome group AAA-EA) production in Uganda are the banana weevil Cosmopolites sordidus and the burrowing nematode Radopholus similis. Endophytic Fusarium oxysporum strains inoculated into tissue culture banana plantlets have shown control of the banana weevil and the nematode. We conducted screenhouse and field experiments to investigate persistence in the roots and rhizome of two endophytic Fusarium oxysporum strains, V2w2 and III4w1, inoculated into tissue-culture banana plantlets of highland cooking banana cultivars Kibuzi and Nabusa. Re-isolation of F. oxysporum showed that endophyte colonization decreased faster from the rhizomes than from the roots of inoculated plants, both in the screenhouse and in the field. Whereas rhizome colonization by F. oxysporum decreased in the screenhouse (4–16 weeks after inoculation), root colonization did not. However, in the field (17–33 weeks after inoculation), a decrease was observed in both rhizome and root colonization. The results show a better persistence in the roots than rhizomes of endophytic F. oxysporum strains V2w2 and III4w1.     

Ectopic Cushing's syndrome in cloacogenic carcinoma of the anal canal: a case demonstrating APUD characteristics

A patient found to have ectopic Cushing's syndrome three months after surgical resection of cloacogenic carcinoma of the anal canal was studied with serial plasma cortisol and ACTH measurements. The effects of therapy on plasma ACTH and cortisol levels were noted. An autopsy was performed immediately after death and liver metastatic tumor tissue was assayed for "small" ACTH, "big" ACTH, PTH, and alpha sub-unit of hCG, Clinical Cushing's syndrome was observed along with nonsuppressible plasma cortisol level. Plasma ACTH only reached the highest normal level but tumor ACTH ("small"), "big" ACTH, alpha sub-unit and PTH were markedly elevated. It was concluded that a case of classic cloacogenic carcinoma of the anal canal produced ectopic Cushing's syndrome. Elevated tumor alpha sub-unit and PTH were not associated with appreciable biologic activity. Ectopic Cushing's syndrome in this disease may imply poorer prognosis.     

Lipid composition of deep-sea hydrothermal vent tubeworm Riftia pachyptila, crabs Munidopsis subsquamosa and Bythograea thermydron, mussels Bathymodiolus sp. and limpets Lepetodrilus spp

Lipid composition was determined for hydrothermal vent species collected by the Deep Submergence Vehicle ALVIN from chimneys at 2,500 m depth on the East Pacific Rise. These are the first lipid biomarker studies for most of these species. Lipid content was low and dominated by polar lipid in the vestimentiferan tubeworm Riftia pachyptila, mussels Bathymodiolus sp. and limpets Lepetodrilus spp. The galatheid (Munidopsis subsquamosa) and most brachyuran adult (Bythograea thermydron) crabs were characterized by higher storage lipid (triacylglycerol). Total polyunsaturated fatty acids were similar in R. pachyptila plume and body, but higher in the posterior part of the soft body, which had more docosahexaenoic acid (2-5% of total FA) compared to the anterior and plume (< or =0.3%). Two sulphur-oxidizing bacterial markers, 16:1(n-7)c and 18:1(n-7)c, were high in R. pachyptila and mussel (up to 23%), but lower in both crab species (4-17%). R. pachyptila had greater nonmethylene interrupted diunsaturated fatty acids (8-13%) than all other species (2-8%). R. pachyptila may desaturate and elongate 18:1(n-7)c to obtain essential polyunsaturated fatty acids 20:5(n-3) and 20:4(n-6). The sterol composition of R. pachyptila included similar amounts of cholesterol and desmosterol, whereas the other species had a more diverse sterol composition. These differences in lipids, fatty acids and sterols reflect diverse nutritional strategies and possibly temperature regimes in these species.     

Transport of the Harmful Bloom Alga Aureococcus anophagefferens by Oceangoing Ships and Coastal Boats

It is well established that cyst-forming phytoplankton species are transported in ships' ballast tanks. However, there is increasing evidence that other phytoplankton species which do not encyst are also capable of surviving ballast transit. These species have alternative modes of nutrition (hetero- or mixotrophy) and/or are able to survive long-term darkness. In our studies of no-ballast-on-board vessels arriving in the Great Lakes, we tested for the presence of the harmful algal bloom species Aureococcus anophagefferens (brown tide) in residual (i.e., unpumpable) ballast water using methods based on the PCR. During 2001, the brown tide organism was detected in 7 of 18 ballast water tanks in commercial ships following transit from foreign ports. Furthermore, it was detected after 10 days of ballast tank confinement during a vessel transit in the Great Lakes, a significant result given the large disparity between the salinity tolerance for active growth of Aureococcus (>22 ppt) and the low salinity of the residual ballast water (~2 ppt). We also investigated the potential for smaller, recreational vessels to transport and distribute Aureococcus. During the summer of 2002, 11 trailered boats from the inland bays of Delaware and coastal bays of Maryland were sampled. Brown tide was detected in the bilge water in the bottoms of eight boats, as well as in one live-well sample. Commercial ships and small recreational boats are therefore implicated as potential vectors for long-distance transport and local-scale dispersal of Aureococcus.     

Determining nitrogen fractions in swine slurry

Nutrient management plans are used to reduce non-point source pollution from animal operations. These plans require manure analysis and use indices to determine nutrient availability. This study evaluated a modified method for determining nitrogen fractions in swine slurry stored under slatted floors, calculating plant available nitrogen, and characterizing nitrogen fractions by holding pit depth. Manure samples were collected from gestating sow and finishing pig holding pits at discrete depths. Ammonium, amino acid, and amino sugar concentrations were significantly different for gestation holding pits by depth, but finishing pig holding pit values were not significantly different by depth. Plant available nitrogen was approximately 74% for gestation and 67% for finishing barn manures. Nitrogen fraction analysis suggests land application of swine manure for crop growth should be managed based on type of nitrogen present in the manure, which can be highly correlated to animal growth stage.     

A study of the mortality and fecundity of Haemonchus contortus in sheep following experimental infections.

The regulation of the fecundity and mortality of H. contortus in sheep was examined using a series of mathematical models. Six-month-old Dorset crossbred lambs were infected once only with various doses of infective H. contortus larvae (500-20,000 larvae). Parasite mortality was found to be an increasing linear function of the magnitude of the initial infection over the range of doses examined. Parasite fecundity was found to remain constant over the intensity and duration of the infection. The average fecundity for H. contortus at the time of slaughter was found to be 7037 eggs per female worm per day. There was no evidence of time-dependent changes in fecundity or density-dependent regulation of fecundity.