Camels carry Middle East respiratory syndrome coronavirus, but little is known about infection age or prevalence. We studied >800 dromedaries of all ages and 15 mother–calf pairs. This syndrome constitutes an acute, epidemic, and time-limited infection in camels <4 years of age, particularly calves. Delayed social separation of calves might reduce human infection risk.

The 5'-3' exonuclease Exo1p from Saccharomyces cerevisiae is required for wild-type levels of meiotic crossing-over and normal meiotic chromosome segregation as is the meiosis-specific MutS homologue, Msh4p. Mutations in both genes reduce crossing-over by approximately two-fold, but deltamsh4 strains have significantly lower viability and a higher frequency of meiosis I non-disjunction. Epistasis analysis indicates a complex interaction between the two genes. Although crossing-over was not detectably lower in the double mutant, viability was significantly worse than either single mutant. Such a result suggests that the two genes are affecting meiotic viability by distinct mechanisms. We propose that deltaexo1 affects chromosome segregation by reducing crossing-over, while deltamsh4 affects both the frequency and distribution of crossovers. Mutation in EXO1 reduces gene conversion frequencies significantly at some but not all loci, suggesting that other enzymes are also involved in DNA resection. We propose that Exo1p plays an early role in establishing some recombination intermediates by generating single-stranded tails. The role of Msh4p is suggested to be in determining whether some recombination intermediates are resolved as crossover events and in generating crossover interference. The synergistic effect of deltaexo1deltamsh4 on spore viability suggests that the two genes have partially compensatory roles in a process affecting meiotic success.

BackgroundThe Houbara bustard (Chlamydotis undulata) is a wild seasonal breeding bird populating arid sandy semi-desert habitats in North Africa and the Middle East. Its population has declined drastically during the last two decades and it is classified as vulnerable. Captive breeding programmes have, hitherto, been unsuccessful in reviving population numbers and thus radical technological solutions are essential for the long term survival of this species. The purpose of this study was to investigate the use of primordial germ cell-mediated chimera technology to produce viable Houbara bustard offspring.Methodology/Principal FindingsEmbryonic gonadal tissue was dissected from Houbara bustard embryos at eight days post-incubation. Subsequently, Houbara tissue containing gonadal primordial germ cells (gPGCs) was injected into White Leghorn chicken (Gallus gallus domesticus) embryos, producing 83/138 surviving male chimeric embryos, of which 35 chimeric roosters reached sexual maturity after 5 months. The incorporation and differentiation of Houbara gPGCs in chimeric chicken testis were assessed by PCR with Houbara-specific primers and 31.3% (5/16) gonads collected from the injected chicken embryos showed the presence of donor Houbara cells. A total of 302 semen samples from 34 chimeric roosters were analyzed and eight were confirmed as germline chimeras. Semen samples from these eight roosters were used to artificially inseminate three female Houbara bustards. Subsequently, 45 Houbara eggs were obtained and incubated, two of which were fertile. One egg hatched as a male live born Houbara; the other was female but died before hatching. Genotyping confirmed that the male chick was a pure-line Houbara derived from a chimeric rooster.ConclusionThis study demonstrates for the first time that Houbara gPGCs can migrate, differentiate and eventually give rise to functional sperm in the chimeric chicken testis. This approach may provide a promising tool for propagation and conservation of endangered avian species that cannot breed in captivity.

A zebra shark, Stegostoma fasciatum, held in captivity at the Burj Al Arab aquarium, produced embryos and pups in the absence of a male. A total of 15 pups were produced from eggs laid within the aquarium over a period of four consecutive years commencing 2007. Parthenogenesis was confirmed through DNA analysis for three pups sampled during the first two consecutive egg cycles and is presumed to be the method of reproduction responsible thereafter.

A comprehensive second-generation whole genome radiation hybrid (RH II), cytogenetic and comparative map of the horse genome (2n = 64) has been developed using the 5000rad horse × hamster radiation hybrid panel and fluorescence in situ hybridization (FISH). The map contains 4,103 markers (3,816 RH; 1,144 FISH) assigned to all 31 pairs of autosomes and the X chromosome. The RH maps of individual chromosomes are anchored and oriented using 857 cytogenetic markers. The overall resolution of the map is one marker per 775 kilobase pairs (kb), which represents a more than five-fold improvement over the first-generation map. The RH II incorporates 920 markers shared jointly with the two recently reported meiotic maps. Consequently the two maps were aligned with the RH II maps of individual autosomes and the X chromosome. Additionally, a comparative map of the horse genome was generated by connecting 1,904 loci on the horse map with genome sequences available for eight diverse vertebrates to highlight regions of evolutionarily conserved syntenies, linkages, and chromosomal breakpoints. The integrated map thus obtained presents the most comprehensive information on the physical and comparative organization of the equine genome and will assist future assemblies of whole genome BAC fingerprint maps and the genome sequence. It will also serve as a tool to identify genes governing health, disease and performance traits in horses and assist us in understanding the evolution of the equine genome in relation to other species.

Taken together, our findings introduce crocin as a candidate chemopreventive agent against HCC.

Broadly neutralizing antibodies (bnAbs) against HIV-1 protect from infection and reduce viral load upon therapeutic applications. However no vaccine was able so far to induce bnAbs demanding their expensive biotechnological production. For clinical applications, nanobodies (VHH) derived from heavy chain only antibodies from Camelidae, may be better suited due to their small size, high solubility/stability and extensive homology to human VH3 genes. Here we selected broadly neutralizing nanobodies by phage display after immunization of dromedaries with different soluble trimeric envelope proteins derived from HIV-1 subtype C. We identified 25 distinct VHH families binding trimeric Env, of which 6 neutralized heterologous primary isolates of various HIV-1 subtypes in a standardized in vitro neutralization assay. The complementary neutralization pattern of two selected VHHs in combination covers 19 out of 21 HIV-1 strains from a standardized panel of epidemiologically relevant HIV-1 subtypes. The CD4 binding site was preferentially targeted by the broadly neutralizing VHHs as determined by competition ELISAs and 3D models of VHH-Env complexes derived from negative stain electron microscopy. The nanobodies identified here are excellent candidates for further preclinical/clinical development for prophylactic and therapeutic applications due to their potency and their complementary neutralization patterns covering the majority of epidemiologically relevant HIV-1 subtypes.

The present study aimed to investigate the differentiation of chicken (Gallus gallus domesticus) primordial germ cells (PGCs) in duck (Anas domesticus) gonads. Chimeric ducks were produced by transferring chicken PGCs into duck embryos. Transfer of 200 and 400 PGCs resulted in the detection of a total number of 63.0 ± 54.3 and 116.8 ± 47.1 chicken PGCs in the gonads of 7-day-old duck embryos, respectively. The chimeric rate of ducks prior to hatching was 52.9% and 90.9%, respectively. Chicken germ cells were assessed in the gonad of chimeric ducks with chicken-specific DNA probes. Chicken spermatogonia were detected in the seminiferous tubules of duck testis. Chicken oogonia, primitive and primary follicles, and chicken-derived oocytes were also found in the ovaries of chimeric ducks, indicating that chicken PGCs are able to migrate, proliferate, and differentiate in duck ovaries and participate in the progression of duck ovarian folliculogenesis. Chicken DNA was detected using PCR from the semen of chimeric ducks. A total number of 1057 chicken eggs were laid by Barred Rock hens after they were inseminated with chimeric duck semen, of which four chicken offspring hatched and one chicken embryo did not hatch. Female chimeric ducks were inseminated with chicken semen; however, no fertile eggs were obtained. In conclusion, these results demonstrated that chicken PGCs could interact with duck germinal epithelium and complete spermatogenesis and eventually give rise to functional sperm. The PGC-mediated germline chimera technology may provide a novel system for conserving endangered avian species.