Sequential bacteriological observations in relation to cell-mediated and humoral antibody responses of cattle infected with Mycobacterium paratuberculosis and maintained on normal or high iron intake

Twenty calves were orally infected with Mycobacterium paratuberculosis before weaning. Ten of these plus 4 non-infected controls were maintained on elevated dietary iron intake from 6 to 33 months of age. During this time, in which the majority of animals were bred, the influence of increased dietary iron upon tests of cellular and humoral immune responsiveness to antigens of the organism were monitored. Results were examined in relation to the organism's capacity to multiply and infect up to 7 portions of the intestinal tract. No significant differences were detected in the degree of intestinal disease or pattern of faecal excretion of M. paratuberculosis in iron supplemented and non-supplemented cattle. Cutaneous delayed-type hypersensitivity (DTH) to johnin PPD developed at 1 month and in-vitro lymphocyte and immunostimulatory activity (LS) to this antigen at 2 months after infection. LS indices were significantly reduced in magnitude in iron-supplemented cattle (p less than 0.01). Most ELISA antibody responses were positive 10 to 17 months after infection and preceded the fewer number of CF responses by several months. Neither of the antibody tests was affected by elevated iron intake. Generally, complete or partial resistance to paratuberculosis was associated with sustained positive monthly LS tests (index greater than or equal to 2.0), whereas antibody levels tended to be sustained only in the more severely affected cattle. Although neither test system was affected by pregnancy the ELISA failed to detect a significant proportion of cattle chronically shedding M. paratuberculosis in faeces.     

Resistance to synthetic pyrethroids in South Australian populations of sheep lice (Bovicola ovis)

SUMMARY Lice were collected from 71 flocks detected as Infested at market Inspection in 1990 and 1991, from 16 flocks where resistance was suspected and from 31 flocks from Kangaroo Island. Susceptibility to cypermethrin was measured by a treated surface technique and survival of lice at 5 ppm or greater was taken as an indication of resistance. The prevalence of resistance was 34% in louse populations from the market inspection sample, 50% in flocks in which resistance was suspected and 68% in flocks from Kangaroo Island. Most resistance factors were in the range 1 to 20 although one louse population with a resistance factor of 91 was found on Kangaroo Island.     

Use of imiquimod 5% cream (Aldara™) in cats with multicentric squamous cell carcinoma in situ: 12 cases (2002–2005)*

Multicentric squamous cell carcinoma in situ (MSCCIS) is a variant of squamous cell carcinoma in cats, commonly referred to as Bowen’s‐like disease. Imiquimod 5% cream (Aldara?) is a novel immune response modifier (IRM) that has been reported as a successful treatment for Bowen’s disease in humans. The purpose of this study was to describe clinical findings, treatment protocols and survival in cats with MSCCIS treated with imiquimod 5% cream and to examine the effects of imiquimod 5% cream in cats with MSCCIS. The expression of papillomavirus group‐specific antigen in the study population was also determined. From review of medical records, 12 cats were identified with a histologic diagnosis of MSCCIS and treatment with imiquimod 5% cream. Initial lesions responded to imiquimod 5% cream in all cats. Most cats (75%) developed new lesions. New lesions also responded to imiquimod 5% cream in all cats treated. Five cats (41%) had side effects suspected to be associated with the use of imiquimod 5% cream, including local erythema (25%), increased liver enzymes and neutropenia (8%), and partial anorexia and vomiting (8%). Kaplan–Meier median treatment duration and median survival time probabilities for cats in this study were 1189 days, respectively. A time to failure model was generated as many cats were censored from analysis well before the aforementioned projected median. This model resulted in a shorter median survival time of 243 days. No patient‐related, tumour‐related or treatment‐related prognostic variables were identified. No expression for papilloma group‐specific antigen was found. Imiquimod 5% cream appears to be well tolerated in the majority of cats, and further studies are warranted to further examine its usefulness in cats with this disease.     

Evidence of parasexual exchange of DNA in the rice blast fungus challenges its exclusive clonality

ABSTRACT We applied DNA markers to determine whether parasexual recombination may contribute to the extreme genetic diversity and variability observed in Magnaporthe grisea, the causal agent of rice blast disease. Dispersed repetitive elements and mapped, low-copy restriction fragment length polymorphism (RFLP) probes were used to detect transfers of DNA between cultured isolates of M. grisea. Low-copy RFLP probes also were used to detect putative recombinants among isolates from well-characterized field populations of the pathogen. Microscopic examination of tufted mycelium between cocultured isolates revealed frequent hyphal fusions. Hyphal tips and conidia were recovered without selection from tufted zones in two separate vegetative pairings involving isolates with dissimilar haplotypes, based on the repetitive element MGR586. Haplotypic changes were observed at a higher frequency in tuft derivatives than in subcultures of each isolate alone. From 136 tuft derivatives analyzed, 5 putative recombinant haplotypes were identified. Introgression was demonstrated with two independent repetitive elements, fosbury and MGR586, as probes on DNA digested with several restriction enzymes. Introgressions were characterized by addition of 1 to 10 MGR586 bands, and 1 to 3 fosbury bands from one parent into the background of the other. Polymorphic single-copy probes were used to analyze putative recombinants. One probe detected an introgression event as predicted by analysis with MGR586. To assess the possible role of parasexual recombination in field populations of the pathogen, isolates in the Philippines previously grouped based on DNA fingerprinting were analyzed with low-copy RFLP markers. Polymorphism in single-copy loci typically was seen between, but not within, putative pathogen lineages. One lineage (designated lineage 4), however, was polymorphic for several probes. For some isolates, alleles at these loci comigrated with alleles characteristic of other lineages, suggesting the transfer of DNA fragments between lineages. One isolate was apparently a merodiploid, carrying an allele typical of lineage 4 plus another allele characteristic of a different lineage. In a survey of isolates from the Indian Himalayas, a merodiploid also was found with single- or low-copy probes. Examination of MGR586 profiles of the putative recombinant and its putative donor strains showed the expected introgression of MGR586 bands. The detection of parasexual DNA exchanges in wild-type strains under unselected conditions and the existence of merodiploids in nature suggest that parasexual recombination occurs in field populations of M. grisea. This raises questions concerning exclusive clonality in the blast fungus.     

Proteomic Analysis of the Venom of Jellyfishes Rhopilema esculentum and Sanderia malayensis

Venomics, the study of biological venoms, could potentially provide a new source of therapeutic compounds, yet information on the venoms from marine organisms, including cnidarians (sea anemones, corals, and jellyfish), is limited. This study identified the putative toxins of two species of jellyfish—edible jellyfish Rhopilema esculentum Kishinouye, 1891, also known as flame jellyfish, and Amuska jellyfish Sanderia malayensis Goette, 1886. Utilizing nano-flow liquid chromatography tandem mass spectrometry (nLC–MS/MS), 3000 proteins were identified from the nematocysts in each of the above two jellyfish species. Forty and fifty-one putative toxins were identified in R. esculentum and S. malayensis, respectively, which were further classified into eight toxin families according to their predicted functions. Amongst the identified putative toxins, hemostasis-impairing toxins and proteases were found to be the most dominant members (>60%). The present study demonstrates the first proteomes of nematocysts from two jellyfish species with economic and environmental importance, and expands the foundation and understanding of cnidarian toxins.