Characterisation of pumpkin yellow vein mosaic virus from India

Yellow vein mosaic disease symptoms occur frequently in pumpkin in India. Diseased plants show vein yellowing, which sometimes coalesces to form chlorotic patches. Infected plants are stunted and flowers drop prematurely, greatly reducing yields. Diseased plants are infected by a begomovirus, designated pumpkin yellow vein mosaic virus (PYVMV), which is transmitted readily and in a persistent manner by the whitefly, Bemisia tabaci. Transmission of PYVMV requires minimum acquisition and inoculation access periods of 30 min and 10 min, respectively. The minimum latent period in the insect is 6 h and the virus persists in the vector for at least 8 days. PYVMV has a narrow host range consisting of a small number of cucurbit species and some tobacco cultivars. It was detected serologically in diseased plants and in viruliferous B. tabaci using polyclonal antibodies in a double‐antibody sandwich enzyme‐linked immunosorbent assay. Reactions with monoclonal antibodies in a triple‐antibody sandwich ELISA showed that PYVMV has an epitope profile distinct from those of other begomoviruses from the Indian sub‐continent. Polymerase chain reaction amplified fragments from the putative viral coat and movement protein genes. Based on comparative phylogeny of complete coat protein gene sequences, PYVMV was most similar to the bipartite Tomato leaf curl New Delhi virus from India and appears to be a new strain of this virus.     

Effect of some Flavonoids and Phenolic Acids on Seed Germination and Rooting

Nandakumar, L. and Rangaswamy, N. S. 1985. Effect of some flavonoidsand phenolic acids on seed germination and rooting.Mdash;J.cxp. Bot. 36: 1313–1319. Effects of isovitexin (isolated from leaves of Rhynchosia minima),leucocyanidin, gallic acid, and protocatechuic acid on seedgermination and subsequent seedling growth of a crucifer Brassicacampestris, and two legumes Lens esculenta and R. minima, aswell as effects of isovitexin on rooting of onion bulbs aredescribed. Neither of the flavonoids affected seed germinationin any of the three systems studied. However, both the flavonoidspromoted seedling growth in B. campestris and L. esculenta;the promotion of root growth was more marked. At 10^–5and 10^–7M, isovitexin also promoted rooting of onion bulbs.In the range of 2.27 ? 10^–4M to 3.28 ? 10^–3M, leucocyanidinpromoted growth of both root and shoot in L. esculenta, whereasin the range 3.28 ? 10^–3M to l.64?lO^–3M it suppressedseedling growth. In contrast to the flavonoids, the two phenolicacids tested inhibited seed germination at 10^–3M, andat lower concentrations they suppressed seedling growth. The promotive effects of the flavonoids isovitexin and leucocyanidin,especially on root growth, hold promise for the use of suchnaturally occurring plant substances in studies on the physiologyof plant growth and development. Key words: Flavonoids, phenolic acids, seed germination, rooting     

Nucellus Cultures of two Cucurbits--Luffa cylindrica and Trichosanthes anguina

Nucellus cultures of Luffa cylindrica and Trichosanthes anguina(Cucurbitaceae) have been established. Tracheary differentiationoccurred in cultures of both taxa. Supplementing the culturemedium with 2,4-D caused limited and diffuse differentiationof tracheary elements. In the absence of 2,4-D, tracheary differentiationwas profuse and the tracheary elements formed compact nodules;the differentiation of tracheary nodules could be traced towell-developed meristemoids. Our results show that the formationof tracheary nodules is an ultimate event in morphogenesis andbears no causal relation to organogenesis. The suitability ofthe nucellus as a system for studies on tracheary differentiationis emphasized.     

WPA guidance on steps,obstacles and mistakes to avoid in the implementation of community mental health care

This paper provides guidance on the steps, obstacles and mistakes to avoid in the implementation of community mental health care. The document is intended to be of practical use and interest to psychiatrists worldwide regarding the development of community mental health care for adults with mental illness. The main recommendations are presented in relation to: the need for coordinated policies, plans and programmes, the requirement to scale up services for whole populations, the importance of promoting community awareness about mental illness to increase levels of help-seeking, the need to establish effective financial and budgetary provisions to directly support services provided in the community. The paper concludes by setting out a series of lessons learned from the accumulated practice of community mental health care to date worldwide, with a particular focus on the social and governmental measures that are required at the national level, the key steps to take in the organization of the local mental health system, lessons learned by professionals and practitioners, and how to most effectively harness the experience of users, families, and other advocates.     

Broad-based resistance to pigeonpea sterility mosaic disease in wild relatives of pigeonpea (Cajanus: Phaseoleae)

Sterility mosaic disease (SMD), an important biotic constraint on pigeonpea (Cajanus cajan) in the Indian subcontinent, is caused by Pigeonpea sterility mosaic virus (PPSMV) transmitted by the eriophyid mite, Aceria cajani. Distinct PPSMV isolates occur in different geographical regions and broad‐based resistance to all these isolates is scarce in cultivated pigeonpea germplasm. Wild relatives of pigeonpea, which are known to possess resistance to several pests and diseases, were evaluated for broad‐based SMD resistance. One hundred and fifteen wild Cajanus accessions from six species (C. albicans, C. platycarpus, C. cajanifolius, C. lineatus, C. scarabaeoides and C. sericeus) were evaluated against three PPSMV isolates prevailing in peninsular India. Evaluations were done under greenhouse conditions in endemic locations of each isolate through mite‐mediated virus inoculation. Fifteen accessions showed resistance to all three isolates: ICP 15614, 15615, 15626, 15684, 15688, 15700, 15701, 15725, 15734, 15736, 15737, 15740, 15924, 15925 and 15926. Most of the wild accessions did not support mite multiplication. The majority of the accessions resistant to PPSMV following inoculations with viruliferous mites were susceptible by graft inoculation, suggesting that vector resistance is conferring resistance to infection with PPSMV. The 15 accessions identified as being resistant to infection to all three virus isolates tested are cross compatible with pigeonpea by traditional breeding. They are therefore useful for exploitation in breeding programmes to increase both the level of SMD resistance and to diversify its genetic base in the cultivated pigeonpea gene pool.     

'BULBIFORMIN', AN ANTIBIOTIC PRODUCED BY BACILLUS SUBTILIS

The antimicrobial spectrum of the antibiotic produced by Bacillus subtilis has indicated that it is chiefly antifungal. In the presence of the antibiotic, a characteristic bulb formation has been observed in the spores and hyphae of the test fungi. The active principle has been shown to be thermolabile. The importance of magnesium in relation to growth and antibiotic production has been indicated. Large quantities up to 30 p.p.m. are required for maximum production of the antibiotic which is not intracellular, but is secreted into the medium.
The data presented suggest that the antibiotic under consideration is different from those of B. subtilis previously described, therefore the name proposed for this antibiotic is 'bulbiformin'.