Increased Capacity for Polycyclic Aromatic Hydrocarbon Mineralization in Bioirrigated Coastal Marine Sediments

Bioirrigation of marine sediments by benthic infauna has the potential to increase both the rate and depth of bacterial mineralization of polycyclic aromatic hydrocarbons (PAHs) by recirculating oxygenated bottom water into sediment burrows. Rates of heterotrophic bacterial production and mineralization of PAHs (naphthalene, phenanthrene, and fluoranthene) were measured in sections of sediment cores sampled from stations in San Diego Bay. Data suggest that rates of PAH biodegradation and bacterial heterotrophy were influenced by bioirrigation by benthic infauna. PAH mineralization and heterotrophic production were higher in core sections where sulfide was not detected relative to core sections containing sulfide. Depth-integrated capacity of the upper 17 cm of sediment to mineralize PAHs was 4 to 10 times higher at the station with bioirrigation coefficients that increased with depth. Remedial dredging of sediments to remove contaminant mass (and presumable lower ecological risk) will also remove benthic infauna. Removal of infauna and the subsequent lowering of bioirrigation in surface sediments would be expected to lower the capacity of intrinsic PAH bioremediation. This could cause local increases in ambient PAH concentration and consequently increase the ecological risk at the site and potentially degrade the health of the ecosystem by removing a sink for PAHs.     

Investigation of apoptosis in cultured cells infected with equine herpesvirus 1

Many viruses alter different stages of apoptosis of infected cells as a strategy for successful infection. Few studies have addressed mechanisms of equine herpesvirus 1 (EHV-1) strain-induced cell death. We investigated the effect of an abortigenic strain (AR8 strain) on heterologous Madin–Darby bovine kidney cells and homologous equine dermis (ED) cells cell lines. We compared morphologic and biochemical features of early and late apoptosis at different postinfection times. We investigated translocation of phosphatidylserine to the cell surface, nuclear fragmentation and changes in the cytoskeleton using flow cytometry and annexin V/propidium iodide staining, DNA laddering, terminal deoxynucleotidyl transferase UTP nick-end labeling assay and immunofluorescence staining of cytokeratin 18 cleavage. AR8 EVH-1 strain interfered with apoptosis in both cell lines, particularly during the middle stage of the replication cycle; this was more evident in ED cells. Although this antiapoptotic effect has been reported for other alpha herpesviruses, our findings may help elucidate how EHV-1 improves its infectivity during its cycle.     

Transmission of Creutzfeldt-Jakob disease to the stumptail macaque (Macaca arctoides).

The successful transmission of Creutzfeldt-Jakob disease from both affected human and chimpanzee brain to stumptail macaques has been accomplished. The incubation period of 5 yr was the same for both animals; however, the course of the disease was longer in the animal receiving the human brain. In both cases, initial mild symptoms slowly remitted only to reappear some 4 mo later. Muscle biopsies revealed changes suggestive of a mild neuropathy. In addition, there appeared to be an increased ability to incorporate 3H-thymidine in untreated cultures of lymphocytes from peripheral blood.     

Analysis of tumor-associated alkyldiacylglycerols and other lipids during radiation-induced thymic leukemogenesis.

Lipid composition of thymuses investigated during the development of thymic leukemogenesis induced by exposing C57BL/6J mice to gamma radiation led to the following conclusions. 1. Alkyldiacylglycerols, a class of lipids that are generally elevated in most neoplastic tissues, occurred only in small quantities (less than 1% of the total lipids) in the thymuses of both control and irradiated mice. However, we found a 3- to 8-fold increase in this fraction in thymic tumors of mice at 5 mo after irradiation when compared to controls of similar age. However, the small quantity of this lipid class in thymic leukemia and the fact that similar levels were found in some samples of involuted thymuses of mice 3 days after irradiation, suggests to us that the level of alkyldiacylglycerols is not sufficiently specific or sensitive for detecting early stages of thymic leukemogenesis. 2. Thymuses 3 days after irradiation and leukemic thymuses contain 2- to 3-fold greater quantities of cholesterol esters than control thymuses. No major differences were found in the distribution of acyl moieties in the cholesterol esters of the various thymus samples from the same aged mice except that in thymic tumors the quantity of 18:1 esters was increased by about 25% over that of the controls. The apparent lack of specificity of increased cholesterol esters for neoplasia indicates that its measurement would not provide a suitable indicator of early neoplastic transformation. 3. Acyl composition of the triacylglycerols of thymuses revealed an increase in the 18:1 and a decrease in the 18:2 acids at 3 days after irradiation when compared to the same aged controls. However, thymic tumors occurring at 5 mo after irradiation contained less 14:0, 16:0, and 16:1 acids and increased amounts of 18:1 and 18:2 acids esterified as triacylglycerols compared to controls. The fatty acid distribution in the phospholipid fraction of thymuses was not altered by the appearance of leukemia.     

Functional Gene Hybridization Patterns of Terrestrial Ammonia-Oxidizing Bacteria

Abstract The biochemical pathway and genetics of autotrophic ammonia oxidation have been studied almost exclusively in Nitrosomonas europaea. Terrestrial autotrophic ammonia-oxidizing bacteria (AAOs), however, comprise two distinct phylogenetic groups in the beta-Proteobacteria, the Nitrosomonas and Nitrosospira groups. Hybridization patterns were used to assess the potential of functional probes in non-PCR-based molecular analysis of natural AAO populations and their activity. The objective of this study was to obtain an overview of functional gene homologies by hybridizing probes derived from N. europaea gene sequences ranging in size from 0.45 to 4.5 kb, and labeled with 32P to Southern blots containing genomic DNA from four Nitrosospira representatives. Probes were specific for genes encoding ammonia monooxygenase (amoA and amoB), hydroxylamine oxidoreductase (hao), and cytochrome c-554 (hcy). These probes produced hybridization signals, at low stringency (30 degreesC), with DNA from each of the four representatives; signals at higher stringency (42 degreesC) were greatly reduced or absent. The hybridization signals at low stringency ranged from 20 to 76% of the total signal obtained with N. europaea DNA. These results indicate that all four functional genes in the ammonia oxidation pathway have diverged between the Nitrosomonas and Nitrosospira groups. The hao probe produced the most consistent hybridization intensities among the Nitrosospira representatives, suggesting that hao sequences would provide the best probes for non-PCR-based molecular analysis of terrestrial AAOs. Since N. europaea can also denitrify, an additional objective was to hybridize genomic DNA from AAOs with probes for Pseudomonas genes involved in denitrification. These probes were specific for genes encoding heme-type dissimilatory nitrite reductase (dNir), Cu-type dNir, and nitrous oxide reductase (nosz). No hybridization signals were observed from probes for the heme-type dNir or nosz, but Nitrosospira sp. NpAV and Nitrosolobus sp. 24-C hybridized, under low-stringency conditions, with the Cu-type dNir probe. These results indicate that AAOs may also differ in their mechanisms and capacities for denitrification.     

Comparative susceptibility of a canine cell line and bluetongue virus susceptible cell lines to a bluetongue virus isolate pathogenic for dogs

Summary Recently, bluetongue virus (BLU) serotype 11 was detected in diseased dogs that had been inoculated with live attenuated vaccine contaminated with this serotype of bluetongue virus (Akita et al., 1994). For various laboratory tests, BLU can be propagated in different cell cultures. No information was found in the literature about the possibility of propagating this virus in canine cells. To determine whether the BLU isolate from the contaminated canine vaccine (BLU-vac) is unique in its ability to replicate in canine cells, this virus was studied in parallel with U.S. prototype strains of BLU (serotypes 2, 10, 11, 13, and 17), in hamster lung (HmLu-1) and canine kidney (MDCK) cell cultures. In HmLu-1 cell cultures, the BLU-vac produced cytopathic effect (CPE) of the same type as the U.S. prototype BLU strains by 4 to 6 d postinoculation. In MDCK cell cultures, all of the BLU strains tested were able to replicate but did not produce CPE. The BLU-inoculated MDCK cells became persistently infected, and these cultures continued to produce infectious BLU even after six serial passages over 2 1/2 mo. In none of these cultures was CPE observed. In mixed cultures containing both HmLu-1 and MDCK cells, CPE first affected the HmLu-1 islands; subsequently, CPE spread also to the areas with MDCK cells. The silent persistent infection of the MDCK cells with BLU indicates that more stringent screening of the cells used in the production of live vaccines for various contaminating viruses is necessary.     

Candidate SNP of CACNA2D1 Gene Associated with Clinical Mastitis and Production Traits in Sahiwal (Bos taurus indicus) and Karan Fries (Bos taurus taurus × Bos taurus indicus)

The present study was conducted to identify polymorphisms in CACNA2D1 gene and their association with clinical mastitis and production traits. Exon 18 and its flanking regions were screened for the presence of SNPs. Statistical analysis was performed to identify association of period of birth, breed, and genotype with mastitis incidence on randomly selected 103 Sahiwal and 102 Karan Fries cattle. PCR-RFLP analysis revealed that g.38819398G?>?A mutation in exon 18 (269?bp amplicon) of CACNA2D1 gene resolved into AA, AG, and GG genotypes in Sahiwal and Karan Fries cattle. Wald chi-square analysis revealed that the period of birth, breed, and genotype were significantly associated with mastitis incidence. GG genotyped cattle were found to be less susceptible to mastitis. Least square analysis revealed that GG and AG genotype animals of G38819398A SNP of CACNA2D1 gene in Sahiwal as well as in Karan Fries cattle were associated with higher average milk yields during 1st, 2nd, and 3rd lactations (P?<?0.01). These observations and their differential association with the incidence of mastitis and production traits can be utilized as an aid to selection for simultaneous improvement of both antagonistic traits; however, validation of results on large number of animals is warranted.