Novel attempts launched toward universal Sarbecovirus vaccine

The emergence of severe acute respiratory syndrome corona-virus 2 (SARS-CoV-2) variants and new coronaviruses raise the demand for universal vaccines.In recent ...     

Characterization of highly pathogenic H5N1 avian influenza A viruses isolated from South Korea

An unprecedented outbreak of H5N1 highly pathogenic avian influenza (HPAI) has been reported for poultry in eight different Asian countries, including South Korea, since December 2003. A phylogenetic analysis of the eight viral genes showed that the H5N1 poultry isolates from South Korea were of avian origin and contained the hemagglutinin and neuraminidase genes of the A/goose/Guangdong/1/96 (Gs/Gd) lineage. The current H5N1 strains in Asia, including the Korean isolates, share a gene constellation similar to that of the Penfold Park, Hong Kong, isolates from late 2002 and contain some molecular markers that seem to have been fixed in the Gs/Gd lineage virus since 2001. However, despite genetic similarities among recent H5N1 isolates, the topology of the phylogenetic tree clearly differentiates the Korean isolates from the Vietnamese and Thai isolates which have been reported to infect humans. A representative Korean isolate was inoculated into mice, with no mortality and no virus being isolated from the brain, although high titers of virus were observed in the lungs. The same isolate, however, caused systemic infections in chickens and quail and killed all of the birds within 2 and 4 days of intranasal inoculation, respectively. This isolate also replicated in multiple organs and tissues of ducks and caused some mortality. However, lower virus titers were observed in all corresponding tissues of ducks than in chicken and quail tissues, and the histological lesions were restricted to the respiratory tract. This study characterizes the molecular and biological properties of the H5N1 HPAI viruses from South Korea and emphasizes the need for comparative analyses of the H5N1 isolates from different countries to help elucidate the risk of a human pandemic from the strains of H5N1 HPAI currently circulating in Asia.     

Amplified Rnase H Activity in Escherichia coli B/R Increases Sensitivity to Ultraviolet Radiation

Strains of E. coli B/r transformed with the plasmid pSK760 were found to be sensitized to inactivation by ultraviolet radiation (UV) and to have elevated levels of RNase H activity. Strains transformed with the carrier vector pBR322 or the plasmid pSK762C derived from pSK760 but with an inactivated rnh gene were not sensitized. UV-inactivation data for strains having known defects in DNA repair and transformed with pSK760 suggested an interference by RNase H of postreplication repair: uvrA cells were strongly sensitized, wild-type and uvrA recF cells were moderately sensitized and recA cells were not sensitized; and minimal medium recovery was no longer apparent in sensitized uvrA cells. Biochemical studies showed that post-UV DNA synthesis was sensitized and that the smaller amounts of DNA synthesized after irradiation, while of normal reduced size as indicated by sedimentation position in alkaline sucrose gradients, did not shift to a larger size (more rapidly sedimenting) upon additional incubation. We suggest an excess level of RNase H interferes with reinitiation of DNA synthesis on damaged templates to disturb the normal pattern of daughter strand gaps and thereby to inhibit postreplication repair.     

Success Factors for Avian Influenza Vaccine Use in Poultry and Potential Impact at the Wild Bird–Agricultural Interface

Thirty-two epizootics of high pathogenicity avian influenza (HPAI) have been reported in poultry and other birds since 1959. The ongoing H5N1 HPAI epizootic that began in 1996 has also spilled over to infect wild birds. Traditional stamping-out programs in poultry have resulted in eradication of most HPAI epizootics. However, vaccination of poultry was added as a control tool in 1995 and has been used during five epizootics. Over 113 billion doses of AI vaccine have been used in poultry from 2002 to 2010 as oil-emulsified, inactivated whole AIV vaccines (95.5%) and live vectored vaccines (4.5%). Over 99% of the vaccine has been used in the four H5N1 HPAI enzootic countries: China including Hong Kong (91%), Egypt (4.7%), Indonesia (2.3%), and Vietnam (1.4%) where vaccination programs have been nationwide and routine to all poultry. Ten other countries used vaccine in poultry in a focused, risk-based manner but this accounted for less than 1% of the vaccine used. Most vaccine “failures” have resulted from problems in the vaccination process; i.e., failure to adequately administer the vaccine to at-risk poultry resulting in lack of population immunity, while fewer failures have resulted from antigenic drift of field viruses away from the vaccine viruses. It is currently not feasible to vaccinate wild birds against H5N1 HPAI, but naturally occurring infections with H5 low pathogenicity avian influenza viruses may generate cross-protective immunity against H5N1 HPAI. The most feasible method to prevent and control H5N1 HPAI in wild birds is through control of the disease in poultry with use of vaccine to reduce environmental burden of H5N1 HPAIV, and eventual eradication of the virus in domestic poultry, especially in domestic ducks which are raised in enzootic countries on range or in other outdoor systems having contact with wild aquatic and periurban terrestrial birds.     

A map of 22 loci on human chromosome 22.

We constructed a genetic linkage map of the entire long arm of human chromosome 22 with 30 polymorphic markers, defining 22 loci. The map consists of a continuous linkage group 110 cM long, when male and female recombination fractions are combined; average distance between the loci is 5.2 cM. All loci were placed on the map with high support against alternative orders (odds in excess of 1000:1). The order of loci presented in our map is in full agreement with that of the previous linkage maps of chromosome 22 and with the physical assignment of markers. Two markers included in this map, KI-831 (D22S212) and pEFZ31 (D22S32), allowed us to better define the region of the (11;22) translocation breakpoint specific for Ewing sarcoma. Ten additional polymorphic markers were placed on the 22-loci map with odds lower than 1000:1 against alternative locations. In total, we have introduced 29 new markers on the linkage map of chromosome 22.     

Population structure and behaviour of crop-raiding elephants in Kibale National Park, Uganda

We examined patterns of crop raiding by elephants across gender and age classes in relation to elephant life history and sociobiology and estimated the quantitative contribution of crops to elephant diet in Kibale National Park (KNP). Elephant dung‐boli sizes were used to estimate age and sex, while the presence of crop remains in the dung of crop‐raiding elephants was used as evidence of repeated raiding. To estimate the expected proportion of elephants raiding per age class, the age distribution of raiders was compared with the age distribution of all KNP elephants. Elephants raiding crops were predominantly males. They began raiding in expected proportions at 10–14 years while a higher than expected proportion raided crops at 20–24 years. These results suggest that crop raiding is initiated at an age when male elephants leave their families and a large proportion of elephants raid when they are approaching reproductive competition. Evidence from dung of crop raiders, suggests that repeated raiding increases with age. Crop raiders derived 38% of their daily forage from the short time spent raiding, consistent with expectations of foraging theory. Males may be more likely to learn crop raiding because they are socially more independent and experience intense mating competition than females.