Non-excitable mutants of Paramecium caudatum, CNR (caudatum non-reversal) are unable to show the avoiding reaction due to the malfunction of voltage dependent Ca2+ channels. Among 4 CNRs, cnrA, cnrB, cnrC and cnrD so far obtained, cnrC cells temporarily change to wild-type phenotype when cnrC are mated with wild type or other CNRs belonging to different loci (conjugation rescue). On the other hand, cnrA shows almost no conjugation rescue during conjugation. Duration of backward swimming of pairs between cnrC and wild type or other mutants controlled by different loci was examined by K+ test solution. Pairs of cnrC and wild type showed heterotypic pair character and short backward swimming at the beginning but showed the same extent of backward swimming as that of wild-type homotypic pairs in 2 hrs from the formation of tight pairs. When the double mutant, cnrC-Kag (K+-agitated; controlled by cnrBKg), was mated with cnrA, duration of backward swimming proceeded gradually. This result suggests that further interaction of the wild-type products with those of cnrBKg is necessary for the expression of Kag phenotype.
Monoclonal antibodies were produced against Babesia equi piroplasms. Three MoAbs reacting with an 18 kDa surface membrane protein (p18) of B. equi in immunoblot analysis, were used to characterize the epitopes on p18. All the three MoAbs recognized the same epitope on p18 as indicated by competitive ELISA. Negative results in two-site ELISA suggest absence of repetitive epitopes on p18. Triton X-114 phase partitioning confirmed that 18 kDa antigen is an integral membrane protein of B. equi piroplasms. As these MoAbs identified a single protein and showed no crossreaction with B. caballi or equine erythrocyte proteins, these can be a candidate to be used in the differential diagnosis of mixed equine piroplasma infections.
We have recently reported the presence of a Babesia ovata like large intraerythrocytic parasite, Babesia sp.1 in the cattle population of Hokkaido in Japan. A 5.5 kilobase(kb) DNA fragment that showed cross-hybridization with the BOZAP6, a DNA probe derived from B. ovata genome, was cloned from the Babesia sp.1 genome and characterized. Beside a sequence that conferred the cross-hybridization, the fragment contained the parasite-specific sequence that did not hybridize with DNAs from B. ovata, B. bigemina, B. bovis, Theileria sergenti, Anaplasma marginale, A. centrale, Eperythrozoon wenyoni and bovine white blood cells. The Babesia sp.1 specific region on the 5.5 kb fragment was excised and subcloned into a plasmid vector as parasite-specific DNA probe (SpS7). Babesia ovata-specific DNA probe (OvS9) was also obtained by deleting a sequence that confers the cross-hybridization with Babesia sp.1 from original BOZAP6 DNA. SpS7 or OvS9 was sensitive enough to detect 5 ng of DNA either from Babesia sp.1 or B. ovata, respectively. These DNA probes, sensitive and either specific for B. ovata or Babesia sp.1, could be useful tools in epidemiological studies to analyze the variations in the bovine Babesia species in Japan.
Trials were conducted in groups of14 day old Ross Broilers and Lohmann Brown laying birds experimentally infected with 350, 1,250, 5,000, 20,000, 80,000, 320,000, or 1,280,000 sporulated oocysts of a field strain of Eimeria tenella. The oocyst output, weight gain and performance, clinical signs and mortality were recorded for 14 days post infection. Birds were necropsied for lesion scoring and histopathological examination. Performance was related to the level of challenge with mortality of up to 80% occurring in birds infected with 20,000 oocysts and above. There was good correlation between clinical signs and post mortem findings, with severe lesions present in birds in the more heavily infected groups. Caecae were engorged and distended with bloody caecal cores. Histopathological examination confirmed the presence of increasing numbers of parasites from day 6 onwards, with massive epithelial destruction and mucosal sloughing in the heavily infected groups.
A study to elucidate the main species of coccidia was carried out on breeder hare reared in an Umbrian intensive game breeding farm and on juvenile hare reared first in cages and subsequently in 9 protected areas in the Province of Perugia (Italy). A total of 2,100 faecal samples from game hare were collected monthly between January 1990-December 1993. Results showed that coccidia were not present in the breeder and juvenile hare kept in cages; conversely, Eimeria leporis and E. semisculpta were detected in the juvenile hare reared in eight of the protected areas but showed a wide range of variability. In addition E. robertsoni, E. townsendi, E. hungarica and E. europea were isolated from the dead hare reared in one protected area with a high coccidial prevalence.