Draft Genome Sequence of the Capripoxvirus Vaccine Strain KSGP 0240, Reisolated from Cattle

Control of lumpy skin disease in cattle is based on vaccination with live attenuated vaccines. The Kenyan strain KSGP 0240 is commonly used to vaccinate ruminants against capripox infections, but the conferred protection is still controversial. In this study, we report the draft genome sequence of the vaccine strain KSGP 0240, reisolated from cattle.

A role for worm cutl-24 in background- and parent-of-origin-dependent ER stress resistance

Organisms in the wild can acquire disease and stress resistance traits that far outstrip the programs endogenous to humans. Finding the molecular basis of such natural resistance characters is a key goal of evolutionary genetics. Standard statistical-genetic methods toward this end can perform poorly in organismal systems that lack high rates of meiotic recombination, like Caenorhabditis worms. Here we discovered unique ER stress resistance in a Kenyan C. elegans isolate, which in inter-strain crosses was passed by hermaphrodite mothers to hybrid offspring. We developed an unbiased version of the reciprocal hemizygosity test, RH-seq, to explore the genetics of this parent-of-origin-dependent phenotype. Among top-scoring gene candidates from a partial-coverage RH-seq screen, we focused on the neuronally-expressed, cuticlin-like gene cutl-24 for validation. In gene disruption and controlled crossing experiments, we found that cutl-24 was required in Kenyan hermaphrodite mothers for ER stress tolerance in their inter-strain hybrid offspring, and was a contributor to the trait in their purebred progeny. These data establish the Kenyan strain allele of cutl-24 as a determinant of a natural stress-resistant state, and they set a precedent for the dissection of natural trait diversity in invertebrate animals without the need for a panel of meiotic recombinants.

Storage root yield of sweetpotato as influenced by sweetpotato leaf curl virus and its interaction with sweetpotato feathery mottle virus, and sweetpotato chlorotic stunt virus in Kenya

The effect of a Kenyan strain of sweetpotato leaf curl virus (SPLCV) and its interactions with sweetpotato feathery mottle virus (SPFMV), and sweetpotato chlorotic stunt virus (SPCSV) on root yield was determined. Trials were performed during two seasons using varieties contrasting in their resistance to sweetpotato virus disease, ‘Kakamega’ and ‘Ejumula’, in a randomized complete block design with sixteen treatments replicated three times. The treatments included plants graft inoculated with SPLCV, SPFMV and SPCSV alone and in possible dual or triple combinations. Yield and yield related parameters were evaluated at harvest. Results showed marked differences in the effect of SPLCV infection on the two varieties: ‘Ejumula’, which is susceptible to SPFMV and SPCSV, suffered no significant yield loss from SPLCV infection, whereas ‘Kakamega’, which is more resistant to SPFMV and SPCSV, suffered an average of 47% yield loss, despite only mild symptoms occurring in both varieties. These results highlight the variability in sensitivity to SPLCV between sweetpotato cultivars as well as a lack of correlation of SPLCV related symptoms with susceptibility to the virus. In addition, they underline the lack of correlation between resistance to the RNA viruses SPCSV and SPFMV and DNA virus SPLCV.

Examination of Taxonomic Uncertainties Surrounding Brucella abortus bv. 7 by Phenotypic and Molecular Approaches

ABSTRACTBrucellataxonomy is perpetually being reshuffled, at both the species and intraspecies levels. Biovar 7 ofBrucella abortuswas suspended from theApproved Lists of Bacterial NamesBrucellaclassification in 1988, because of unpublished evidence that the reference strain 63/75 was a mixture ofB. abortusbiovars 3 and 5. To formally clarify the situation, all isolates previously identified asB. abortusbv. 7 in the AHVLA and ANSES strain collections were characterized by classical microbiological and multiple molecular approaches. Among the 14 investigated strains, including strain 63/75, only four strains, isolated in Kenya, Turkey, and Mongolia, were pure and showed a phenotypic profile in agreement with the former biovar 7, particularly agglutination with both anti-A/anti-M monospecific sera. These results were strengthened by molecular strategies. Indeed, genus- and species-specific methods allowed confirmation that the four pure strains belonged to theB. abortusspecies. The combination of most approaches excluded their affiliation with the recognized biovars (biovars 1 to 6 and 9), while some suggested that they were close to biovar 3.These assays were complemented by phylogenetic and/or epidemiological methods, such as multilocus sequence analysis (MLSA) and variable-number tandem repeat (VNTR) analysis. The results of this polyphasic investigation allow us to propose the reintroduction of biovar 7 into theBrucellaclassification, with at least three representative strains. Interestingly, the Kenyan strain, sharing the same biovar 7 phenotype, was genetically divergent from other three isolates. These discrepancies illustrate the complexity ofBrucellataxonomy. This study suggests that worldwide collections could include strains misidentified asB. abortusbv. 7, and it highlights the need to verify their real taxonomic position.

Studies on the transmission and course of infection of a Kenyan strain of Theileria mutans

SummaryTheileria mutans (Aitong) isolated from cattle exposed in the Narok District of Kenya and blood-passaged through cattle 8 times, appeared to have lost its original pathogenicity for cattle. It was demonstrated that the parasite was trans-stadially transmissible by the tick Amblyomma variegatum but not by Rhipicephalus appendiculatus. Four tick–bovine passages were made using A. variegatum, and infective parasites were also harvested from A. variegatum nymphs which had been fed for 5 days on rabbits. Blood containing piroplasms, or lymphoid cells infected with schizonts taken from cattle, at the 2nd tick–bovine passage were shown to be infective on inoculation.The course of the T. mutans infections in the cattle was studied. In tick-induced infections macroschizonts occurred transiently, persisting longest in circulating lymphoid cells. Microschizonts were rarely detected. The macroschizonts were morphologically distinct from those of other Theileria species described from East Africa.In tick-induced infections, the piroplasm parasitaemia increased rapidly and there was evidence of restored pathogenicity of the parasite since high piroplasm parasitaemias were associated with a marked anaemia.

Babesia bigemina in Kenya: experimental transmission by Boophilus decoloratus and the production of tick-dervied stabilates

A Babesia-free batch of laboratory reared Boophilus decoloratus ticks was infected with a Kenyan strain of Babesia bigemina by feeding them on a steer infected by inoculation of a blood stabilate. The engorged female ticks showed developing stages of B. bigemina in their haemolymph and subsequently their progeny transmitted the parasite to a susceptible splenectomized steer.Attempts were made to produce stabilates from pre-fed larvae and nymphs derived from infected batches of B. decoloratus. Only the stabilates derived from the nymphs pre-fed either on cattle or rabbits produced B. bigemina infection when inoculated intravenously into susceptible cattle.