Ultrastructural localization of anaplasmal antigens (Pawhuska isolate) with ferritin-conjugated antibody.

Antibodies from a cow with an experimentally induced infection of the Pawhuska isolate of bovine anaplasmosis were conjugated with ferritin and used to label antigenic sites in preparations of parasitized erythrocytes. Intact erythrocytes did not label on the extracellular surface. Ferritin-conjugated antibody did not pass through the intact erythrocyte to label the parasite, probably due to the large molecular size of the antibody. Damage to erythrocytic plasmalemma and inclusion body in the hemolyzed erythrocytes and complement-fixation antigen allowed labeling of anaplasmal inclusion structures. The positively labeled structures were outer surface of the pellicle, chromatin of the initial body, and inclusion appendage. Unlabeled structures included inner organismic membrane of the initial body, inclusion membrane, fibrillar protoplasmic network of the initial body, and small electron-dense bodies derived from the initial body.     

Molecular cloning of complementary DNA from a pneumopathic strain of bovine viral diarrhea virus and its diagnostic application.

A pneumopathic strain of bovine viral diarrhea virus was grown in cell culture and purified. Genomic ribonucleic acid was extracted, polyadenylated at the 3' end, and copied into complementary DNA after oligo-dT priming. Complementary DNA was male double stranded and cloned into the pUC9 plasmid. Approximately 200 complementary DNA clones varying in length from 0.5 to 2.5 kilobases were obtained. Hybridization assays indicated that the sequences isolated were specific for bovine viral diarrhea virus and that at least 5.5 kilobases of bovine viral diarrhea virus genome was represented in the library of complementary DNA clones, the majority of which may have originated from the 3' end of the virus genome. One cloned complementary DNA sequence was used as a 32P-labelled hybridization probe for bovine viral diarrhea virus detection. The probe hybridized with all cytopathic and noncytopathic strains of bovine viral diarrhea virus tested and was 100 times more sensitive than infectivity assays for the detection of bovine viral diarrhea virus. Hybridization did not occur with nucleic acids from bovine coronavirus, bluetongue virus, bovine adenovirus or uninfected cell cultures. Native plasmid DNA sequences, labelled with 32P, did not hybridize with bovine viral diarrhea virus ribonucleic acid.     

Effects of Starvation and Feeding on Lipid Class and Fatty Acid Profile of Late Stage Mud Crab,Scylla serrata,larvae

Lipid class and fatty acid (FA) analysis were conducted on newly molted, fed, and starved zoea V and megalopa of the mud crab, Scylla serrata (S. serrata). Larvae starved for 4 d showed a substantial decrease in total FA content, from 49.67 μg/mg to 13.94 μg/mg ash‐free dry weight (AFDW) at the zoea V stage, and from 38.47 μg/mg to 10.40 μg/mg AFDW at the megalopa stage. This depletion indicates that S. serrata larvae effectively utilize stored lipid reserves for energy during periods of food deprivation. Megalopa subjected to longer starvation periods, however, did not utilize lipid as the major energy source after day 4, suggesting increased reliance on protein catabolism during prolonged starvation. At both larvae stages the major FAs were 18:1n‐9, 16:0, 20:5n‐3 (eicosapentaenoic acids, EPA), 18:3n‐3 (linolenic acid, LNA), 18:0 and 22:6n‐3 (docosahexaenoic acid, DHA) and this FA profile persisted in both fed and starved larvae. The highly unsaturated fatty acids (HUFA), EPA, DHA, and arachidonic acid (20:4n‐6, AA) were not conserved in tissue during starvation, indicating that HUFA requirements might be lower for S. serrata larvae than shown for other crustaceans. Similarly, a high level of LNA in newly molted zoea V and megalopa were rapidly depleted in unfed larvae, indicating that this FA had an important role as an energy reserve. Throughout the study, FAs from the polar lipid fraction dominated larvae tissues, while FAs from the neutral lipid constituted the largest accessible energy reserve during starvation (depleted from 23.05 to 1.23 μg/mg AFDW in zoea V, and from 19.00 to 1.27 μg/mg AFDW in megalopa). The results of this study provide new insight into lipid utilization of S. serrata larvae during development, an important step toward development of formulated diets for use in mud crab hatcheries.     

Development of Procedures for Sex-sorting Frozen–Thawed Bovine Spermatozoa

Dairy bull sperm may be sex‐sorted, frozen and used to artificially inseminate heifers with acceptable fertility if the herd is well‐managed. One drawback to the technology is that donor bulls must be located within a short distance of the sorting facility in order to collect semen, which limits the number of bulls from which sorted sperm are available. A successful method used to overcome this limitation in sheep is sex‐sorting from frozen–thawed semen and refreezing for artificial insemination. This technique is attractive to the dairy industry, and therefore a series of three experiments was designed to investigate the optimal methods to prepare, sex‐sort and re‐freeze frozen–thawed bovine sperm. Sperm were prepared for sorting by density gradient separation in either PureSperm^® or BoviPure?, followed by staining in one of three diluents (Androhep^®, Bovine Sheath Fluid + 0.3% BSA or TALP buffer). Sperm were sorted and collected into Test yolk buffer, and frozen in an extender containing 0, 0.25, 0.375 or 0.5% Equex STM Paste. Frozen–thawed sperm were better orientated (p = 0.006) and had fewer damaged membranes (8.7 ± 0.6% vs 19.5 ± 2.4%; p = 0.003) after centrifugation in PureSperm^® rather than BoviPure? gradients. Sperm orientation (p < 0.05) and motility (69.9 ± 3.0 vs 55.6 ± 4.0; p < 0.001) were highest after staining in Androhep^® rather than in TALP buffer. Sperm were more motile (58.2 ± 4.7 vs 38.7 ± 3.5; p < 0.001) and had better acrosome integrity (74.3 ± 2.9 vs 66.8 ± 2.0; p < 0.001) after freezing in an extender containing 0.375% Equex STM Paste than in extender without Equex. Hence, a protocol has been developed to allow frozen–thawed bull sperm to be sex‐sorted with high resolution between the sexes, then re‐frozen and thawed with retention of motility and acrosome integrity.     

Cambrian burgess shale animals replicated in clay minerals

Although the evolutionary importance of the Burgess Shale is universally acknowledged, there is disagreement on the mode of preservation of the fossils after burial. Elemental mapping demonstrates that the relative abundance of elements varies between different anatomical features of the specimens. These differences reflect the compositions of the minerals that replicated the decaying organism, which were controlled by contrasts in tissue chemistry. Delicate morphological details are replicated in the elemental maps, showing that authigenic mineralization was fundamental to preserving these fossils, even though some organic remains are also present.     

The many faces of bovine viral diarrhea virus.

The complex and unique nature of bovine viral diarrhea virus(BVDV) continues to present challenges to infectious disease re-searchers, veterinarians, and the cattle industry. In addition, the BVDV pathogen will undoubtedly continue to change and present itself in many different configurations.