Non-infectivity of semen from bulls infected with bovine leukosis virus

Semen and serum were obtained from four bovine leukosis virus (BLV) infected bulls from each of eight bull studs. The samples from the 32 bulls were frozen and stored in liquid nitrogen for subsequent testing. The sera were tested for antibodies to BLV by the agar gel immunodiffusion (AGID) method. Thirty of the bulls were found to be infected with BLV. Pairs of sheep were intraperitoneally inoculated with semen pools of the four bulls from each bull stud. None of the sheep developed antibodies to BLV. A later challenge with BLV infected lymphocytes resulted in the infection of all challenged sheep indicating that they were susceptible to BLV infection. The results provide evidence that transmission of BLV via leukocyte free semen from BLV infected bulls does not occur.     

Detection of conjugated dienoic fatty acids in human vascular smooth muscle cells treated with conjugated linoleic acid

Conjugated linoleic acids (CLA) have attracted scientific interest due to their potential beneficial effects on atherosclerosis. Recent studies demonstrated that conjugated metabolites of CLA are found in tissues of CLA-fed animals and cultured cells treated with CLA. This observation has gained in importance since it has recently been shown that these metabolites of CLA exert specific biological activities. Therefore, the present study aimed to explore the potential formation of metabolites of cis-9, trans-11 CLA, trans-10, cis-12 CLA and trans-9, trans-11 CLA in cells of the vascular wall, which has not yet been shown. Examination of fatty acid composition of total cell lipids using Ag+-HPLC, GC-FID and GC-MS analysis revealed a significant isomer-specific formation of conjugated metabolites of CLA such as CD16:2, CD20:2 and CD22:2 in human coronary artery smooth muscle cells treated with various CLA isomers. Different CD16:2/CLA ratios between various CLA isomers as observed in the present study indicate that fatty acid metabolism is differently affected by the configuration of the double bonds. In conclusion, the observation from the present study suggests that the effects of CLA in vascular cells might not only be mediated by CLA itself but also by its conjugated metabolites. Future studies using highly purified conjugated metabolites of CLA are necessary to study their role in mediating biological effects of CLA in cell culture systems.     

The Nucleocapsid Protein of Human Coronavirus NL63

Human coronavirus (HCoV) NL63 was first described in 2004 and is associated with respiratory tract disease of varying severity. At the genetic and structural level, HCoV-NL63 is similar to other members of the Coronavirinae subfamily, especially human coronavirus 229E (HCoV-229E). Detailed analysis, however, reveals several unique features of the pathogen. The coronaviral nucleocapsid protein is abundantly present in infected cells. It is a multi-domain, multi-functional protein important for viral replication and a number of cellular processes. The aim of the present study was to characterize the HCoV-NL63 nucleocapsid protein. Biochemical analyses revealed that the protein shares characteristics with homologous proteins encoded in other coronaviral genomes, with the N-terminal domain responsible for nucleic acid binding and the C-terminal domain involved in protein oligomerization. Surprisingly, analysis of the subcellular localization of the N protein of HCoV-NL63 revealed that, differently than homologous proteins from other coronaviral species except for SARS-CoV, it is not present in the nucleus of infected or transfected cells. Furthermore, no significant alteration in cell cycle progression in cells expressing the protein was observed. This is in stark contrast with results obtained for other coronaviruses, except for the SARS-CoV.     

Isolation of human antibody repertoires with preservation of the natural heavy and light chain pairing

The humoral immune system in higher vertebrates is unique in its ability to generate highly diverse antibody responses against most pathogens as well as against certain malignancies. Several technologies have been developed to exploit this vast source of potentially therapeutic antibodies, including hybridoma technology, phage display and yeast display. Here, we present a novel, high-throughput technology (the Symplex Technology) for rapid direct cloning and identification of human antigen-specific high-affinity antibodies from single antibody-producing cells of immune individuals. The utility of the technology was demonstrated by isolation of diverse sets of unique high-affinity antibodies against tetanus toxoid and influenza virus from immunized volunteers. Hence, the Symplex Technology is a new method for the rapid isolation of high-affinity antibodies directly from humans.     

Host physiological status determines phage-like particle distribution in the lysate

Bacteriophage morphotype diversity and latent period duration upon induction were correlated with the host population growth. The prophages of the lysogenic Vibrio sp. (DSM14379) were induced with mitomycin C in a batch culture with different salinity, substrate concentration or composition, and at different temperatures. Under all experimental conditions, phages were induced and a population of different complete and incomplete phage-like particles was observed in the lysate. Under favorable growth conditions, the phage-like particle community in the lysate was overpopulated with phage tail-like rigid rods. The number of rods was reduced in samples with low organic carbon concentration, samples with 8% and 10% NaCl, and samples induced at 40 and 43 degrees C. Although all lysates contained all phage-like particle-size fractions, their relative abundances varied. Up to a fivefold difference in phage-like particle size was observed in lysates. Size distribution of phage-like particles changed along temperature, salinity and organic carbon gradients. Results also indicated that the latent period of the induced phage-like particle population converged to approximately 90 min above a growth rate of 1.0 h(-1). At lower host growth rates, the latent period generally increased. However, at 40 and 43 degrees C and at low peptone-yeast extract concentration in the growth medium, the latent period remained short. We propose that different host physiological conditions influence organic matter composition upon prophage induction and may thus affect virus-controlled flow of the energy and carbon in the ecosystem.