Reciprocal complementation of movement function of potato viruses X and A.

During isolation of strains of potato viruses X (PVX) and A (PVA) from indigenously collected potato germplasm, an inseparable association between these viruses was discovered. As a result, all the hosts of PVX, used to free PVX from PVA, also showed infection of PVA along with PVX. Furthermore, Nicandra physaloides, which is a host of PVA but not PVX, also did not free PVA from PVX. These results suggested a reciprocal complementation of movement function of these viruses due to which they together infected various hosts sensitive to PVX or PVA. Relative concentration of PVX, in all the hosts tested, was much higher than that of PVA.

Effect of pH, ions, bovine serum albumin and heterologous antisera on the stability of immunosorbed flexuous potato viruses.

Electron microscopic studies on the stability of immunosorbed (trapped) virions of potato viruses X, S and Y0 (PVX, PVS and PVY0) revealed disintegration and dislodging of PVY0 virions upon incubation with (1) antisera to PVX, PVS, or both diluted in saline, (2) 0.86% NaCl (saline) or 0.1 mol/l CaCl2 but not with 0.1 mol/l CaSO4 or 0.1 mol/l MgSO4. PVX virions, on the other hand, showed partial dislodging upon incubation with an antiserum to PVS diluted in saline, but complete disintegration and dislodging with saline. 0.1 mol/l CaCl2 caused partial dislodging while MgCl2, CaSO4 or MgSO4 (all 0.1 mol/l) had no apparent adverse effect. PVS virions were not affected by saline, CaCl2, MgCl2, CaSO4 or MgSO4 (all 0.1 mol/l) and were only partially dislodged by antisera to PVX or PVY0. Disintegration and/or dislodging of the PVX and PVY0 virions was prevented when (1) they were fixed with glutaraldehyde prior to incubation or (2) the virus extract contained bovine serum albumin (BSA) or (3) heterologous antisera were diluted in 0.1 mol/l phosphate buffer (PB) before use except the PVS antiserum which still caused disintegration and dislodging of PVY0 virions. Prior fixation of virions prevented their disruption and dislodging by saline only in the case of PVY0 but not PVX. On the other hand, BSA reverted the adverse effect of saline but not that of the PVS antiserum on PVY0 virions. The results presented here suggest (1) a disruptive effect of Cl' on PVX and PVY0 virions particularly when it was associated with Na+ and (2) an interaction between the immunosorbed virions of PVX or PVY0 and the antiserum to PVS.

Mesangial proliferative glomerulonephritis in chronic obstructive pulmonary disease.

Ten patients of chronic obstructive pulmonary disease were studied for changes in ultrastructure of the glomeruli, serum immunoglobulin and complement levels. The glomeruli showed proliferation in the mesangium in 90% patients and electron dense deposits in the mesangium in 30% patients. IgA and IgG were usually elevated whereas complements were usually depressed in most of these patients. It is suggested that repeated respiratory infections in these subjects may be responsible for mesangioproliferative type of glomerulonephritis, high IgA and IgG levels. The complements are activated and they take part in immune complex formation getting deposited in mesangium.

Detection of sugarcane bacilliform virus in sugarcane germplasm.

Sugarcane bacilliform virus (SCBV), a badnavirus was found in sugarcane genotypes of Saccharum officinarum L., S. barberi Jesw., S. sinense Roxb., S. robustum Brand and Jesw., and Saccharum hybrids. In most of the suspected genotypes the virus was found associated with clear foliar symptoms. However, certain symptom-free clones carried the virus too. The virus was detected by immuno-electron microscopy (IEM) and enzyme-linked immunosorbent assay (ELISA) in suspected clones. The virions measured about 108-118 x 20-21 nm in size. The virus was serologically closely related to another badnavirus, banana streak virus (BSV). Virus titer was low in most of the genotypes. However, a close correlation between symptoms expression and virus titer existed in some genotypes.

Immunosorbent electron microscopic studies on a tobamovirus causing brinjal necrotic mosaic.

Serological relationships of brinjal necrotic mosaic virus (BNMV), a strain of tobacco mosaic virus (TMV) causing necrotic mosaic disease of brinjal in India to other TMV strains was investigated by immunosorbent electron microscopy (ISEM). The intensity of trapping and decoration revealed a close relationship of BNMV to TMV-D, TMV-U1 and TMV-WU1 strains, and a distant relationship to TMV-A1 and TMV-P11 strains. There was a negligible relationship to TMV-P14, tomato mosaic virus (ToMV) and cucumber green mottle mosaic virus (CGMMV). Therefore, BNMV is proposed to be distinct from the previously reported TMV-A1 strain of brinjal.

Morphological changes in the flexuous potato viruses upon decoration in immunosorbent electron microscopy.

Effect of titer and pH of decorating antiserum, and the virus-source host species on the virion morphology upon decoration of potato viruses X, S and Y was studied. There was good decoration without any apparent adverse effect in the case of PVX and PVS with exception of pH 6.0 and antiserum titer 1:0.5, which caused decoration of only a small proportion of the virions. On the other hand, the PVYo virion morphology showed only slight to extensive disorganization depending on the pH and titer of the antiserum and the virus-source host species. Virion structure was, however, preserved when either PVYo (o strain) and its antiserum were made to react in liquid phase, or virions were fixed with 3% glutaraldehyde before decoration.

Factors influencing immune electron microscopy of flexuous potato viruses.

Effects of pH of extraction buffers, pH and titer of trapping antisera and their combinations, virus acquisition time and virus host on the trapping efficiency of flexuous potato viruses X, S and Y (PVX, PVS and PVY) in immune electron microscopy were evaluated. Addition of ethylene-diamine-tetraacetic acid to the extraction buffer improved trapping of PVY, adversely affected PVS but not PVX. Combinations of antisera had differential adverse effect on trapping which was maximum with the mixture of three antisera. Mixture of antisera to PVX and PVY had the least adverse effect on trapping of PVX and PVY as compared to the mixture with PVS antiserum. Trapping of PVX and PVY was good and almost at par at all the dilutions of the antisera while that of PVS was good up to 1000-fold only. Prolonged virus acquisition time significantly increased the number of virions trapped. Trapping was affected both by the pH of the antiserum and the extraction buffer, while in the case of PVY it was also affected by the host species.