Tuberculosis in wild seals and characterisation of the seal bacillus

SUMMARY Tuberculosis was diagnosed in 3 otariid seals found dead on beaches at 3 locations on the south coast of Western Australian between May 1990 and March 1991. This confirms that tuberculosis is present in the 2 native seals (Neophoca cinerea and Arctocephalus forsteri) in Western Australian waters. Mycobacterium sp isolated from the lungs of 2 of the seals were studied to determine the similarity of the strains to each other, to the strains isolated during 1986 from Australian sea lions and New Zealand fur seals kept in captivity at a marine park near Perth, Western Australia, and to a strain isolated in 1988 from a seal trainer who worked with the infected captive seals for 3 years. After restriction endonuclease analysis (REA) with the endonucleases Bst Ell, Bcl I and Pvu II, one of the wild seal strains appeared to have identical DNA fragment patterns to the strains from the captive seals and the seal trainer. The other wild seal isolate had identical REA profiles using Bst EII and Bcl I, but a minor difference was detected using Pvu II. Differences in these isolates were more clearly seen in restriction fragment length polymorphisms after hybridisation with two DNA probes. The secretory protein MPB70, present in M bovis, was not detected in wild seal isolates using sodium dodecyl sulphate polyacrylamide gel electrophoresis and Western blotting techniques. Analysis of protein and DNA fragment profiles indicated that seal tuberculosis isolates form a unique cluster within the M tuberculosis complex.     

Assessment of clonal fidelity of micropropagated gerbera plants by ISSR markers

True-to-type clonal fidelity is one of the most important pre-requisites in micropropagation of crop species. Genetic fidelity of in vitro raised 45 plants of gerbera (Gerbera jamesonii Bolus) derived from three different explants, viz., capitulum, leaf and shoot tips, was assessed by 32 ISSR markers, for their genetic stability. Out of 32 ISSR markers, 15 markers produced clear, distinct and scorable bands with an average of 5.47 bands per marker. The markers designed from AG motif amplified more number of bands. The markers anchored at 3′ ends produced high number of consistent bands than unanchored markers. Fifteen ISSR markers generated a total of 3773 bands, out of which 3770 were monomorphic among all the clones. The Jaccard's similarity coefficient revealed that out of 45 clones derived from different explants, 44 were grouped into a single large cluster alongwith the mother plant with a similarity coefficient value of 1.00, whereas one clone (C38) remained ungrouped. The clones derived from capitulum and shoot tip explants did not show any genetic variation, whereas, one of the leaf-derived clones exhibited some degree of variation.     

Alteration in important quality traits and antioxidant activities in Brassica oleracea with Ogura cybrid cytoplasm

In vegetable brassicas, cytoplasmic male sterility (CMS) system is the most preferred mechanism for hybrid seed production and Ogura cybrid cytoplasm is the only source used widely. Effects of the alien cybrid cytoplasm on important quality traits need to be understood for their effective use in breeding programme. In analysing 38 Ogura cybrid cytoplasm‐based cauliflower CMS lines, it was revealed that introgression of Ogura cytoplasm resulted in significant alteration in important quality traits. Cupric reducing antioxidant activity and ferric reducing ability of plasma values were increased up to 5–10 times in different genotypes. Among 38 analysed CMS lines, concentration of plant pigments such as anthocyanin, total chlorophylls and ascorbic acid was reduced in 21, 17 and 32 genotypes, respectively. However, the concentration of total carotenoids and β‐carotene was elevated in most of the CMS lines and total carotenoid was increased up to 20 times in the CMS line, Ogu13‐85‐2A. The results indicate the role of nuclear–cytoplasmic interaction and mitochondrial genome in determining concentration of different quality traits.     

Inheritance of resistance to lindane in a laboratory-selected strain of Tribolium castaneum (Herbst)

Studies on the inheritance of resistance to lindane in a laboratory-selected strain of Tribolium castaneum, by making crosses between the resistant and a susceptible strain, showed that resistance in this strain is controlled by an autosomally inherited single gene which is incompletely dominant.     

Detection and molecular characterization of naturally transmitted sheep associated malignant catarrhal fever in cattle in India

Malignant catarrhal fever (MCF) is a fatal herpesvirus infection of domestic and wild ruminants, with a short and dramatic clinical course characterized primarily by high fever, severe depression, swollen lymph nodes, salivation, diarrhea, dermatitis, neurological disorders, and ocular lesions often leading to blindness. In the present study, fatal clinical cases of sheep associated malignant catarrhal fever (SA-MCF) were identified in cattle in the state of Karnataka. These cases were initially presented with symptoms of diarrhea, respiratory distress, conjunctivitis, and nasal discharges. Laboratory diagnosis confirmed the detection of ovine herpesvirus-2 (OvHV-2) genome in the peripheral blood samples of two ailing animals. The blood samples collected subsequently from sheep of the neighboring areas also showed presence of OvHV-2 genome indicating a nidus of infection in the region. The positive test results were further confirmed by nucleotide sequencing of the OIE approved portion of tegument gene as well as complete ORF8 region of the OvHV-2 genome. Phylogenetic analysis based on the sequence of the latter region indicated close genetic relationship with other OvHV-2 reported elsewhere in the world.     

Mutations affecting nodulation in grain legumes and their potential in sustainable cropping systems

Many spontaneous and a large number of induced mutants that show altered nodulation pattern have been isolated in pea, soybean, common bean, faba bean, chickpea, groundnut and pigeonpea. Available information on nodulation mutants in these crops is summarised. The importance of nodulation mutants in basic studies on plant-microbe symbiotic interactions, nitrogen fixation and breeding of cultivars with higher yield and nitrogen fixation rate are examined. The nodulation mutants, after inoculation with specific bacterial strains or a number of different strains, show either: no nodulation (nod-), few nodules (nod+/-), ineffective nodulation (fix-), hyper nodulation (nod++) or hypernodulation even in the presence of otherwise inhibitory nitrate levels (nts). No spontaneous hypernodulation or nts mutants have been found, all have been induced in independent experiments using different cultivars of pea, soybean and common bean after mutagenising seeds. Most nodulation mutants show monogenic recessive inheritance, though semi-dominant and dominant inheritance is also reported. Nodule number is controlled by a process known as autoregulation; hypernodulating mutants show relaxed autoregulation. By grafting shoots of hypernodulating soybean mutant on normal nodulating soybean, mungbean and hyacinth bean, presence of a common, translocatable signal has been shown. Nodulation mutants have contributed to the understanding of the genetic regulation of host-symbiont interactions, nodule development and N fixation. Initially, the hypernodulating mutants were found to be poor in yield. Using the induced hypernodulating mutant, a new soybean cultivar ‘Nitrobean 60’, has been released in Australia. This cultivar is reported to have given 15% higher yield over cv. ‘Bragg,’ and contributed a higher amount of fixed N to the following cereal crop in rotation. Prospects of using the nodulation mutants in developing grain legume cultivars that combine high yield with high residual N, within the bioenergetic constraints, for developing sustainable cropping systems are examined. This revised version was published online in August 2006 with corrections to the Cover Date.     

Spice oil cinnamaldehyde exhibits potent anticandidal activity against fluconazole resistant clinical isolates

Fluconazole resistance is becoming an important clinical concern. We studied the in vitro effects of cinnamaldehyde against 18 fluconazole-resistant Candida isolates. MIC₉₀ of cinnamaldehyde against different Candida isolates ranged 100–500 μg/ml. Growth and sensitivity of the organisms were significantly affected by cinnamaldehyde at different concentrations. The rapid irreversible action of this compound on fungal cells suggested membrane-located targets for its action. Insight studies to mechanism suggested that cinnamaldehyde exerts its antifungal activity by targeting sterol biosynthesis and plasma membrane ATPase activity. Inhibition of H⁺-ATPase leads to intracellular acidification and cell death. Toxicity against H9c2 rat cardiac myoblasts was studied to exclude the possibility of further associated cytotoxicity. The observed selectively fungicidal characteristics against fluconazole-resistant Candida isolates signify a promising candidature of this essential oil as an antifungal agent in treatments for candidosis.