Epidemiology and diagnosis of Mycobacterium tuberculosis in captive Asian elephants (Elephas maximus).

The deaths of two Asian elephants (Elephas maximus) in August 1996 led the United States Department of Agriculture to require the testing and treatment of elephants for tuberculosis. From August 1996 to September 1999. Mycobacterium tuberculosis infection was confirmed by culture in 12 of 118 elephants in six herds. Eight diagnoses were made antemortem on the basis of isolation of M. tuberculosis by culture of trunk wash samples; the remainder (including the initial two) were diagnosed postmortem. We present the case histories, epidemiologic characteristics, diagnostic test results, and therapeutic plans from these six herds. The intradermal tuberculin test, enzyme-linked immunosorbent assay serology, the blood tuberculosis test, and nucleic acid amplification and culture are compared as methods to diagnose M. tuberculosis infection in elephants.     

Effect of biocontrol agents and biofertilizers on root rot,yield, harvest index and nutrient uptake of cassava (Manihot esculanta Crantz)

Cassava is an important subsidiary food and industrial raw material in the tropics. Root rot disease, caused by Phytophthora palmivora, poses a serious threat to cassava cultivation in Tamil Nadu, India. Field experiments (2008–09) were conducted to study the effect of biocontrol agents (Trichoderma spp. and Pseudomonas fluorescens) and biofertilizers (Azospirillum, vesicular–arbuscular mycorrhizal fungi and phosphorus-solubilizing bacteria) on root rot, yield, harvest index and nutrient uptake of cassava at two NPK rates. The design of the experiment was a split plot with two NPK rates, recommended and 50% recommended rate, as the main plot treatments and five biocontrol agents and biofertilizers as subplot treatments. The results clearly indicated that use of a bioinoculants consortium significantly reduced root rot infection/disease incidence over uninoculated controls. Azospirillum significantly improved the yield of cassava at 50% of the recommended rate of NPK. NPK rates had no significant impact on harvest index of cassava and Trichoderma and vesicular–arbuscular mycorrhizal fungi resulted in a higher harvest index even at 50% of the recommended NPK rate. Nitrogen, phosphorus and potassium uptake was significantly improved when treated with biofertilizers and/or a consortium.     

Pectate lyases of Erwinia chrysanthemi: Pel E-like polypeptides and pelE homologous sequences in strains isolated from different plants

Pel E, one of the four major pectate lyases produced by Erwinia chrysanthemi (Echr) strain EC16, was purified to homogeneity and was found to have an apparent molecular weight of 47 500 and a pI of 10. Antibodies produced against this preparation inhibited Pel E activity, but did not affect Pel A, Pel B or Pel C activities. Immunotitration revealed that Pel E accounted for a major fraction of the total extracellular Pel activity ranging from 40–60% in culture and potato tuber tissue. Isoelectric focusing of the extracellular Pels produced by various Echr strains indicated that while the Pel profiles of strains isolated from various hosts were different, the profiles of strains isolated from the same host were very similar. A significant proportion (ranging from 39 to 74%) of the Pel activity of these strains was inhibited by the anti-Pel E antibodies. DNA hybridization under stringent conditions indicated the presence of pelE homologous sequences in the genomes of E. chrysanthemi strains. We conclude that a Pel E-like enzyme occurs in all E. chrysanthemi strains examined.     

Brugia malayi in Mastomys natalensis: efficacy of mebendazole in combination with Freund's complete adjuvant.

The chemotherapeutic efficacy of mebendazole given in combination with Freund's complete adjuvant (FCA) against Brugia malayi in multimammate rat was evaluated. Animals treated with mebendazole, orally at 200 mg/kg x 5 consecutive days along with FCA given subcutaneously (s.c.) on day -10, day 0 and day +15 of the drug treatment killed 48.51% of the adult worms. This drug given alone at the same regimen and by the same route showed only 18.7% mortality rate on adults. Mebendazole given intraperitoneally along with FCA given s.c., however, was four times more efficacious as filaricide than mebendazole alone. Nevertheless, the animals receiving FCA alone also revealed 23.5% mortality rate of adult worms. The animals receiving a combination therapy or FCA alone showed significant increase in antibody titre to the filariae which however decreased in the later stages. No enhancement of antibody level could be detected in animals treated with mebendazole alone. The non-specific immunopotentiation induced by FCA appeared to play a major role in enhancing the activity of mebendazole.     

An Outbreak of Gangrenous Syndrome among Buffaloes and Cattle in West Bengal: Clinicopathological Studies

Gangrenous syndrome/Degnala disease was recorded in a large number of buffaloes and cattle in Murshidabad district of West Bengal, India. Fusarium spp. had been isolated from the mouldy paddy straw which were fed to the animals. There was a reduction in the incidence of the disease following withdrawal of the mouldy paddy straw. Histopathological examination showed necrosis and loss of architectural details in the skin.     

Molecular systematics in Chrysanthemum × grandiflorum (Ramat.) Kitamura

An attempt was made to understand the molecular systematics and genetic differences between 10 original chrysanthemum cultivars and 11 mutants. The similarity among the cultivars and mutants varied from 0.17 to 0.90 using RAPD analyses, a simple but efficient method to distinguish cultivars and to assess parentage. Two distinct groups were found. Two cultivars were present as a separate group showing differences from all other cultivars. Mutants with different flower colour could be identified at the molecular level using RAPD technique holding promise to identify unique genes as SCAR markers. A high genetic distance among the different chrysanthemums showed that there exists a possibility of introgressing new and novel genes from the chrysanthemum gene pool.     

Genetic and physiological evidence for the production of N-acyl homoserine lactones by Pseudomonas syringae pv. syringae and other fluorescent plant pathogenic Pseudomonas species

N-acyl homoserine lactones (AHLs) function as cell density (quorum) sensing signals and regulate diverse metabolic processes in several gram negative bacteria. We report that strains of Pseudomonas syringae pvs. syringae (Pss), tabaci and tomato as well as P. corrugata and P. savastanoi produce difussible AHLs that activate the lux operons of Vibrio fischeri or the tra::lacZ fusion of Agrobacterium tumefaciens. In Pss strain B3A, AHL production occurs in cell density dependent manner. Nucleotide sequence and genetic complementation data revealed the presence of ahlI_Pss, a luxI homolog within the Ahl⁺ DNA of Pss strain B3A. The DNA expresses in AHL-deficient strains of P. fluorescens and E. carotovora subsp. carotovora (Ecc), and restores extracellular enzyme production and pathogenicity in the Ecc strain. The derivatives of Pss strains B3A and 301D carrying chromosomal ahlI::lacZ do not produce AHL, but like their wild type parents, produce extracellular protease and the phytotoxin syringomycin as well as elicit the hypersensitive reaction in tobacco leaves. While these strains also produce a basal level of -galactosidase activity, the expression of ahlI::lacZ is substantially stimulated in the presence of multiple copies of the DNA or by the addition of cell-free spent cultures containing AHL. The activation of -galactosidase production occurs with spent cultures of some, but not all Pseudomonas strains which produce AHL as indicated by the Lux and tra::lacZ assays. Pss strains deficient in the global regulatory genes, gacA or lemA, produce very low levels of AHL. Since inactivation of ahlI_Pss eliminates AHL production and since Ahl⁺ Pseudomonas strains carry the homolog of ahlI_Pss, we conclude that ahlI_Pss specifies a key step in AHL biosynthesis and it has been conserved in many plant pathogenic pseudomonads.     

Effect of Growth Regulators on the Productivity of Some Major Oilseed Crops

A number of field experiments were conducted at the Viswavidyalaya Research Farm during 1984–85 to 1986–87 to study the effects of five growth regulators viz. Miraculan (a triacontanol based growth stimulant), Nutron (1-triacontanol growth stimulant), Planofix ( α -napthylacetic acid), Paras or Mixtalol (Higher alcoholic carbon compounds) and N-triacontanol on productivity of five different major oilseed crops viz. rapeseed ( Brassica campestris L. var. yellow sarson), mustard ( Brassica juncea L. Czern and Coss), sesame ( Sesamum indicum L.), linseed ( Linum usitatissimum L.) and safflower ( Carthemus tinctorius L.). Results showed the positive influence of growth regulators on the productivity of crops (10–40 % increase in yield); however the influence was not consistent over the years. N-triacontanol when tried on mustard only improved the grain yield significantly, more so when applied with paras or planofix, sesame was most influenced by spraying planofix and paras. Nutron favourably influenced safflower and linseed. The test weight of grains followed by the number of pods/plant were influenced most by the application of growth regulators. Inconsistency in results over the years, however, need further investigations on the timing of spraying.     

Genotypic variability in vegetable amaranth (Amaranthus tricolor L for foliage yield and its contributing traits over successive cuttings and years

Summary Twenty nine strains of vegetable amaranth (Amaranthus tricolor were grown for two successive seasons to study different selection parameters for foliage yield and its nine contributing morphological and quality traits. The strains AV-38 (5.06 kg/plot) and AV-31 (5.04 kg/plot) recorded highest foliage yield, followed by AV-30 (4.78 kg/plot) and AV-23 (4.70 kg/plot). The protein and carotenoid content averaged 1.24 ± 0.03 mg/100 mg and 0.83 ± 0.02 mg/g respectively. The leaves of A. tricolor also have considerable quantities of ascorbic acid (112.33 ± 5.00 mg/100 g) and fibre (8.39 ± 0.10%). The mean of individual cuttings for plant height, leaf size, stem diameter, foliage yield, protein, ascorbic acid and fibre content increased with successive cuttings till third cutting and thereafter showed a decline. Genotypic coefficient of variation (GCV) values ranged from 6.80 to 28.25%. However, the fibre content, branches/plant, leaves/plant, plant height and stem diameter showed lowest values of GCV. The values of heritability estimates were high for all the traits in all the cuttings as well as on pooled basis and ranged from 0.89 for branches/plant to 0.98 for foliage yield. Highest expected genetic advance was noticed for ascorbic acid (57.48%), followed by foliage yield (48.30%) and leaf size (29.51%).