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Summary: Chlamydia suis has been detected in numerous disease conditions of pigs, particularly in eye infections. This study examined recurring conjunctivitis cases in five commercial pig farms in Japan. 40.5% of the cases were identified as Chlamydia positive using impression cytology of ocular smears and a genus‐specific direct fluorescent antibody. C. suis was detected in 59.5% of the samples using PCR tests targeting 16S‐23S rRNA intergenic spacer region (ISR) and ompA gene. Genetic analysis of PCR amplicons revealed nine sequence variants of 16S‐23S rRNA ISR and 20 sequence variants within ompA gene. Among C. suis‐positive conjunctivitis cases, 36.4% showed concurrent infection with 2–4 varied ompA sequence types and 9.1% showed multiple 16S‐23S rRNA ISR sequence types of C. suis. Multiple genotypes were found circulating in four of five farms. All 20 detected strains and 25 previously reported C. suis strains were grouped into four clusters. Japanese C. suis strains were closely related to American and European strains indicating wide distribution of these genetically variant strains. This study is the first to show multiple and genetically diverse C. suis strain associations in pig conjunctivitis. [ABSTRACT FROM AUTHOR]

With 1 table Backcrosses were attempted of F1 hybrids of spring wheat genotypes (HS 375 and C 306) and winter wheat genotypes (Saptdhara and Tyari) with the Indian rye (Secale cereale L.) landrace 'Lahaul Local'. Intergeneric hybridizations using pollen of maize and Imperata cylindrica (2n = 20), a wild and weedy species, were conducted in the wheat‐rye‐derived backcross BC1F1 and BC1F2 generations to study the relative efficiency of the two chromosome elimination approaches in the induction of haploid plants. Although seed formation was similar with both pollen sources, the relative frequency of embryo‐carrying seeds ranged from 8% to 30% with I. cylindrica, whereas with maize, no embryo‐carrying seed was obtained. Comparisons of induction of haploid plants in the wheat‐rye backcross derivatives showed that the wheat × I. cylindrica system was superior to the wheat × maize system and was also cost effective as it shares the flowering season with wheat in sub‐temperate conditions. [ABSTRACT FROM AUTHOR]

To study genetic diversity and occurrence of Chlamydophila psittaci, a total of 1,147 samples from 11 avian orders including 53 genera and 113 species of feral and captive birds were examined using ompA gene based nested PCR. Three types of chlamydiae: C. psittaci (94.12%), C. abortus (4.41%) and unknown Chlamydophila sp. (1.47%) were identified among 68 (5.93%) positive samples (Psittaciformes-59, Ciconiiformes-8 and Passeriformes-1). Based on nucleotide sequence variations in the VD2 region of ompA gene, all 64 detected C. psittaci strains were grouped into 4 genetic clusters. Clusters I, II, III and IV were detected from 57.35%, 19.12%, 10.29% and 7.35% samples respectively. A single strain of unknown Chlamydophila sp. was found phylogenetically intermediate between Chlamydophila species infecting avian and mammalian hosts. Among Psittaciformes, 28 out of 81 tested species including 10 species previously unreported were found to be chlamydiae positive. Chlamydiosis was detected among 8.97% sick and 48.39% dead birds as well 4.43% clinically normal birds. Therefore, it was observed that though various genetically diverse chlamydiae may cause avian chlamydiosis, only a few C. psittaci strains are highly prevalent and frequently associated with clinical/subclinical infections.