Genetics of resistance to Puccinia recondita in two wheat crosses

Leaf rust resistance genes were identified in the common wheat variety ‘HUW 206’ and line HUWL 39 by inoculating their seedlings with 20 pathotypes of diverse avirulence–virulence combinations. The inheritance patterns and allelic relationships were studied by crossing these wheats with ‘Agra Local1 and a set of Thacher’ near-isogenic lines with genes for resistance. Seedling resistance studies revealed the presence of genes Lr1, Lr10 and Lr26 in ‘HUW 206’ and genes Lr10 and Lr26 in HUWL 39. The presence of genes Lr1 and Lr10 was confirmed indirectly by testing for the linked genes Sr31 and Yr9. An F₁ test for progressive necrosis in crosses of the lines with ‘Spica’ revealed the absence of Lr13.     

Involvement of higher order interactions addressing complex polygenetically controlled inheritance of downy mildew [Sclerospora graminicola (Sacc.) Schrot] resistance in pearl millet [Pennisetum glaucum (L.) R.Br.]

Inheritance of downy mildew [Sclerospora graminicola (Sacc.) Schrot]resistance was studied using generation mean analysis in pearl millet [Pennisetum glaucum (L.) R.Br.]. Eleven basic generations, namely, P₁, P₂, F₁, F₂, B₁, B₂, B₁F₂, B₂F₂, L₁, L₂ and L₃ of three crosses involving six diverse lines for downy mildew incidence were evaluated under artificial epiphytotic conditions over two environments. The downy mildew incidence was best fitting for digenic, trigenic and tetragenic ratios when fitted into classical Mendelian ratios demonstrating involvement of two or more genes. Digenic and trigenic interaction models were adequate in the case of crosses I and III respectively, to account for the total variability in generation means. Unlike severity, comparative estimates of gene effects over two environments were mostly consistent in all crosses for prevalence. Most of the epistatic and major gene effects were found significant in all crosses for both the disease traits. Non-allelic interactions particularly at three-gene loci viz., w (additive × additive × additive) and y (additive × dominance × dominance) in cross II and all trigenic interactions in cross III were predominant. Duplicate dominance (cross I) and complementary epistasis (crosses II and III) were observed for both the traits revealing inconsistency of gene effects over crosses. The gd₁ (interaction of additive gene effect with e₁) and gh₁(interaction of dominant gene effect with e₁) were significant in crosses I and II, indicating interaction of additive and dominance gene effects with environments. Thus a breeding method that can mop up the resistant genes to form superior gene constellations interacting in a favorable manner against pathotype I would be more suitable to accelerate the pace of resistance improvement. This revised version was published online in August 2006 with corrections to the Cover Date.     

Anti-viral activity of methyl 1-chloro-7-methyl-2-propyl-1h-benzo[d] imidazole-5-carboxylate against white spot syndrome virus in freshwater crab (Paratelphusa hydrodromous)

Shrimp farming industries are subjected to severe economic loss due to a disease called white spot syndrome, a viral disease caused by white spot syndrome virus (WSSV) in penaeid shrimp. Numerous active compounds in the market possess anti-viral activity against the white spot syndrome virus, yet the issue remains unsolved. The present study was carried out to determine the anti-viral activity of methyl 1-chloro-7-methyl-2-propyl-1h-benzo[d] imidazole-5-carboxylate (C₁₃H₁₅N₂O₂Cl) against WSSV. The anti-viral activity of the synthetic compound was determined in freshwater crabs. Crabs were divided into three different experimental groups: healthy control groups (N.C.) received NTE buffer, positive control group (P.C.) crabs received WSSV, and treatment group crabs received WSSV along with synthetic weight compound. Experimental groups were observed for 30 days post-infection. Three different organs (gills, muscles, and head soft tissue (HST)) were dissected from all three groups and analyzed using molecular-based techniques, including polymerase chain reaction (PCR), Western blot, and histopathology. Clinical signs of WSSV were observed in the positive and N.C. groups; however, the treatment group showed a 100% survival rate. Confirmation was done using PCR, Western blot, and histopathology. These results demonstrated that the given synthetic compound has significant anti-viral activity against WSSV.

     

Seedling Peroxidase and IAA Oxidase Activities in Relation to Hybrid Vigour in Pearl Millet (Pennisetum americanum L. Leeke)

Seedlings of three hybrids and their parental lines were analyzed for growth, and peroxidase as well as IAA oxidase activities in cytoplasmic and salt-extracted ionically bound fractions with a view to evaluate heterosis in pearl millet. The hybrid vigour was manifested in roots and shoots of all the three hybrids clearly for growth and activities of peroxidase and IAA oxidase except the wall-bound IAA oxidase. Either better parental or mid-parental heterosis was discernible. The role of peroxidase and IAA oxidase systems in meristematic activity and removal of excessive auxin levels to bring about maximal growth response in the hybrids is discussed.     

Phylogenetic analysis of recent classical swine fever virus (CSFV) isolates from Assam, India

Classical swine fever (CSF), a highly contagious viral disease of pigs, is endemic in India. As there is no information concerning the accurate genetic typing of classical swine fever virus (CSFV) isolates in India, 16 CSF viruses isolated during 2005-2007 from domestic pigs in different districts of Assam were typed in 5′ UTR (150 nucleotides). To confirm the genetic typing results and to study the genetic variability, selected viruses were also analyzed in E2 (190 nt) and NS5B gene (409 nt) regions. Phylogenetic analysis revealed that all the 16 CSFV isolates analyzed belonged to group 1 and subgroup 1.1 in contrast to the situation in other Asian countries. Additionally, analysis in E2 and NS5B region placed the Indian isolates in a clearly separated clade within subgroup 1.1. The results suggest that subgroup 1.1 CSF viruses are currently circulating in India, which is important for epidemiology and control of CSF.     

Single radial hemolysis test for the detection of rinderpest antibody

Summary The single radial hemolysis [SRH] test was employed for detection of rinderpest antibodies in post-vaccinated serum samples as also in serum samples from animals recovered from rinderpest infection. The results were compared with counterimmunoelectrophoresis [CIE] and serum neutralisation [SN] tests. The CIE test was found to be more sensitive than SRH but because of ease and simplicity SRH can also be used for monitoring antibody development after vaccination.

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Resumen Se utilizó la prueba radial sencilla de hemólisis (RSH) para detectar anticuerpos de rinderpest, en muestras de suero de animales vacunados y recuperados de la enfermedad. Los resultados se compararon con las pruebas de contrainmunoelectroforésis (CIE) y sero neutralización (SN). La prueba CIE fue más sensitiva que la RSH, pero debido a la sencillez de manejo, se recomienda la RSH para medir el nivel de anticuerpos post vacunales.

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Résumé Le test d’hémolyse radiale simple (HRS) a été utilisé pour la détection des anticorps antibovipestiques dans des échantillons de sérums après vaccination et aussi dans des échantillons de sérums d’animaux convalescents. Les résultats ont été comparés avec les tests de contre-immunoélectrophorèse (CIE) et de séroneutralisation (SN). On a trouvé que le test CIE est plus sensible que le HRS mais par suite de son aisance et de sa facilité, le HRS peut aussi être employé pour suivre le développement des anticorps après vaccination.

     

Role of iron and iron chelation therapy in oxygen free radical mediated tissue injury in an ascending mouse model of chronic pyelonephritis

The contribution of iron towards the free radical generation leading to renal tissue damage was assessed using a non-obstructive ascending mouse model for chronic pyelonephritis. The parameters studied include luminol dependent chemiluminescence (LDCL), histopathology and some biochemical investigations. We found that iron enhanced the renal tissue damage and led to renal scarring, an end point in chronic renal inflammation, irrespective of the bacterial strain studied. In addition a role of iron chelation therapy as a treatment for chronic renal inflammation is also suggested.