Recognition and differentiation of seven whitefly-transmitted geminiviruses from India, and their relationships to African cassava mosaic and Thailand mung bean yellow mosaic viruses

Particles resembling those of geminiviruses were found by immunosorbent electron microscopy in extracts of plants infected in India with bhendi yellow vein mosaic, croton yellow vein mosaic, dolichos yellow mosaic, horsegram yellow mosaic, Indian cassava mosaic and tomato leaf curl viruses. All these viruses were transmitted by Bemisia tabaci whiteflies, all reacted with at least one out of ten monoclonal antibodies to African cassava mosaic virus (ACMV), and all reacted with a probe for ACMV DNA-1, but scarcely or not at all with a full-length probe for ACMV DNA-2. Most of the viruses were distinguished by their host ranges when transmitted by whiteflies, and the rest could be distinguished by their pattern of reactions with the panel of monoclonal antibodies. Horsegram yellow mosaic virus was distinguished from Thailand mung bean yellow mosaic virus by its lack of sap transmissibility, ability to infect Arachis hypogaea, failure to react strongly with the probe for ACMV DNA-2 and its pattern of reactions with the monoclonal antibodies. Structures resembling a ‘string of pearls’, but not geminate particles, were found in leaf extracts containing malvastrum yellow vein mosaic virus. Such extracts reacted with two of the monoclonal antibodies, suggesting that this whitefly-transmitted virus too is a geminivirus. All seven viruses from India can therefore be considered whitefly-transmitted geminiviruses.     

Anatomical dissemination of circumsporozoite protein in wild Afrotropical Anopheles affects malaria sporozoite rate determination by ELISA

The head, thorax, wings, legs and abdomen of 320 wild-caught Anopheles gambiae Giles sensu lato and 115 An.funestus Giles were tested by an enzyme-linked immunosorbent assay (ELISA) for Plasmodium falciparum Welch to determine how anatomical dissemination of circumsporozoite (CS) protein could affect the estimation of malaria sporozoite rates by ELISA. Of fifty-three Anopheles with CS protein detected in any body part, positive reactions were observed for 58.5% of heads, 67.0% of thoraces, 39.6% of wings, 52.8% of legs and 60.4% of abdomens. Mean absorbance values (range 0-2.00) were highest in thorax samples (1.17), followed by heads (0.80), abdomens (0.67), wings (0.48) and legs (0.46). Circumsporozoite protein was present in the wings or legs, but not in the head or thorax, in 11.3% (6/53) of the infected Anopheles. The ELISA infection rate of 12.8% (41/320) for An.gambiae would have increased to 14.7% (47/320) by inclusion of six mosquitoes with CS protein in wings or legs alone. The slight overestimation of the proportion of infective mosquitoes due to disseminated CS protein would have little effect on estimates of relative infection rates by ELISA for field-collected Anopheles, with abdomens removed prior to testing. However, the widespread dissemination of CS protein indicates that sporozoite load estimates by ELISA, for mosquitoes without abdomens, may not provide adequate measurements of the numbers of sporozoites in the salivary glands. Operationally, careful processing of mosquito samples for the determination of infectivity rates by ELISA is necessary to prevent the mixing of wings or legs among samples representing individual mosquitoes.     

Sexual maturity in sea trout, Salmo trutta L., running up the River Calonne (Normandy, France) at the 'finnock' stage

Sexual maturation in sea trout ( Salmo trutto L.) running up the River Calonne (Normandy, France), at the finnock stage, is characterized. Autopsy of 118 finnock in summer showed that 87 ± 7% aged 2+ and 33 ± 15% aged 1 + were undergoing gametogenesis. In autumn all the fish were maturing. The analysis of plasma levels of 11-ketotestosterone, 17β-oestradiol, maturational gonadotropin and vitellogenin showed that only females in vitellogenesis can be well identified in summer (plasma vitellogenin greater than 0.30 mg ml^-1). The morphological recognition of females among 134 autumn finnock and the ELISA assay of plasma vitellogenin of 814 summer finnock, demonstrated that vitellogenic females represented 12 ± 2%0 of the 1 + individuals and 46 ± 2% of 2+ fish captured during the 1985 run. The question of a possible relationship between the salinity tolerance ofjuvenile trout migrating towards the sea in the spring and their age on first migration in the river is discussed.     

SMV不同毒株在大豆植株内的病毒浓度比较

用SMV不同毒株接种大豆后,定期检测植株体内的病毒浓度。结果各毒株接种48小时后即在部分植株顶芽内洲出病毒,按种后20—25天植株内病毒含量最高。     

Infusion of tumor necrosis factor (TNF) causes an increase in circulating TNF-binding protein in humans

Serum samples from cancer patients receiving intravenous infusions of recombinant tumor necrosis factor (rTNF) and recombinant interferon-gamma (rIFN-gamma) were analyzed for TNF and the TNF-binding protein (TNF-BP). TNF-BP is a soluble fragment of the transmembrane TNF receptor with antagonistic effects to TNF and is released by proteolytic cleavage of the receptor. During a 60-min infusion of rTNF, peak serum levels of rTNF were observed after 30 to 60 min and a transient increase of circulating TNF-BP was observed with peak levels between 30 and 120 min. Injection of IFN-gamma alone did not affect the levels of TNF and TNF-BP. Thus administration of rTNF leads to release into the circulation of TNF-BP, which may modulate both systemic and local effects of TNF and influence its therapeutic efficacy.     

The initiation of legumin synthesis in immature embryos of Pisum sativum L. grown in vivo and in vitro

A highly sensitive immunoassay has been used for the detection of a major storage protein, legumin, in embryos of Pisum sativum L.; with this technique nanogram quantities could be measured. In the two varieties tested, legumin could be detected in embryos in vivo, when they had attained a fresh weight of 2·10^-3 g and 3·10^-3 g, respectively. Contrary to earlier claims, embryos cultured in vitro were shown to be capable of initiating legumin synthesis. This capacity to initiate legumin synthesis was confirmed by two-dimensional isoelectric focusing-electrophoresis and fluorography; embryos harvested before initiation of legumin synthesis and cultured in radioactive medium were shown to have synthesized legumin subunits. The amounts of legumin and total protein synthesized per unit fresh weight were consistently greater in vitro than in equivalent embryos grown in vivo.Abbreviations ELISA Enzyme-linked immunosorbent assay - BSA bovine serum albumin - IgG immunoglobulin - SDS sodium dodecyl sulphate - DSP Pisum cv. Dark Skinned Perfection     

Serological detection and antigenic variation of two whitefly-transmitted geminiviruses: tobacco leaf curl and croton yellow vein mosaic viruses

A panel of 25 monoclonal antibodies (MAbs) raised against particles of two heterologous whitefly-transmitted geminiviruses (begomoviruses) was used in triple antibody-sandwich ELISA (TAS-ELISA) to determine the detectability and epitope profiles of 26 Indian isolates of tobacco leaf curl virus (TLCV) and 13 of croton yellow vein mosaic virus (CYVMV). Stock cultures of the two viruses had indistinguishable epitope profiles although they differ in symptomatology and particle stability. Their epitope profiles also strongly resembled those of Indian isolates of bhendi (okra) yellow vein mosaic and Indian cassava mosaic (ICMV) viruses. TLCV isolates from Andhra Pradesh, Gujarat and Karnataka States differed slightly in epitope profile: they reacted with at least eight out of 10 MAbs raised to ICMV but only one to four out of 15 MAbs raised to African cassava mosaic virus (ACMV). Virus isolates serologically indistinguishable from TLCV were detected in symptom-bearing weeds (Acanthospermum hispidum, Ageratum conyzoides, Euphorbia geniculata, Parthenium hysterophorus) found in leaf curl-affected tobacco fields and shown previously to be experimental hosts of TLCV. Indian TLCV isolates had small, consistent differences in epitope profile from Pakistani isolates but large differences from isolates from Burkina Faso, Malawi or Uganda. Isolates from the three African countries reacted with four or five of the ACMV MAbs but only one or two of the ICMV MAbs, and there were small but consistent inter-country differences. CYVMV isolates from three Indian States showed less epitope variation than did Indian isolates of TLCV. TAS-ELISA with MAb SCR 18 was a more sensitive test for detecting Indian TLCV isolates than was double antibody-sandwich ELISA with polyclonal antibodies.