Arbuscular mycorrhizal associations in different forest tree species of Hazarikhil forest of Chittagong, Bangladesh

Biodiversity of arbuscular mycorrhizal (AM) colonization and AM fungal spores were studied in the roots and rhizosphere soils of Acacia catechu (L.f). Wild., A. mangium Willd, Anthocephala cadamba Miq., Artocarpus chaplasha Roxb., Chickrassia tabularis A. Juss., Swietenia macrophylla King., Tectona grandis L. from plantations; Albizia procera (Roxb.) Benth., A. falcataria L., Alstonia scholaris (L.) R. Br., Aphanamixis polystachya (Wall.) Parker., Hydnocarpus kurzii (King.) Warb., Heynea trijuga Roxb., Lagerstroemia speciosa (L.) Pers., Messua ferrea Linn., Podocarpus nerifolia Don., Swintonia floribunda Griff., Syzygium fruticosum (Roxb.) DC., S. grandis (Wt.) Wal. from forest and nursery seedlings of A. polystachya, A. chaplasha, Gmelina arborea Roxb. and S. cuminii (L.) Skeels from Hazarikhil forest, Chittagong of Bangladesh. Roots were stained in aniline blue and rhizosphere soils were assessed by wet sieving and decanting methods. The range of AM colonization varied significantly from 10%-73% in the plantations samples. Maximum colonization was observed in A. mangium (73%) and minimum colonization was observed in C. tabularis (10%). Vesicular colonization was recorded 15%-67% in five plantation tree species. The highest was in A. cadamba (67%) and the lowest was in T. grandis; A. chaplasha and C. tabularis showed no vesicular colonization. Arbuscular colonization was recorded 12%-60% in four plantation tree species. The highest was in A. mangium (60%) and the lowest was in A. cadamba. Roots of Artocarpus chaplasha, C. tabularis and T. grandis showed no arbuscular colonization. Among 12 forest tree species, nine tree species showed AM colonization. The highest was in A. falcataria (62%) and the lowest was in S. fruticosum (10%). Significant variation in vesicular colonization was recorded in seven forest tree species. The highest was in H. trijuga (52%) and the lowest was in L. speciosa (18%). Hydnocarpus kurzii, M. ferrea, P. nerifolia S. fruticosum and S. grandis showed no vesicular colonization. Arbuscular colonization was recorded in seven forest tree species. The highest was in A. falcataria (60%) and the lowest was in A. procera (10%). All the nursery seedlings showed AM colonization and the range was 10%-73%. Vesicules were recorded in G. arborea (40%) and S. cumini (40%). Arbuscular colonization was recorded in G. arborea (100%) and S. cumini (100%). Spore population was recorded 77-432/100 g dry soils, 80-276/100 g dry soils, and 75-153/100g dry soils in plantation, forest and nursery, respectively. Glomus and Acaulospora were dominant genera among the six AM fungi recorded. Significantly positive correlation was observed between AM colonization and AM fungal spore population in Hazarikhil plantation tree species, forest tree species and nursery tree seedlings. The present study showed the biodiversity of root colonization and AM fungi are active in nutrient cycling, survivals and seedling establishment of the plants in the Hazarikhil forest, plantation and nursery.     

Comparison of ecological condition and conservation status of English yew population in two Austrian gene conservation forests

English yew Taxus baccata L. has been catalogued as endangered tree species and prone to extinction in Austria as well as many other parts of Europe. The present work is based on the comparison of the natural population of two gene conservation forests from different geographic locations in Austria where the spatial structure, regeneration status and possible conservation measures are examined. The pole stand distribution varied distinctly in each sites. The total no of individuals per ha （DBH ≥5 cm）, average DBH and average height were 492 n.hm^-2, 8.8 cm and 6.3 m in Stiwollgraben whereas in Leininger Riese 45 n.hm^-2, 16.3 cm and 7.6 m respectively. Over 79% of the Stiwollgraben population were represented the good health condition, while in Leininger Riese it was less then 49 % which means population of Stiwollgraben is in better condition compared to Leininger Riese. The sites differed considerably in the pattern of regeneration but pattern were consistent with the dynamics depicted by the age distribution. Considering the one-year-old seedlings Stiwollgraben contains 13 019 individuals.hm^-2 whereas Leininger Riese only 1 368. Surprisingly there were no any saplings in respect of 51 to 150 cm height classes in both sites and 30 to 50 cm in Stiwollgraben. In that context the conservation of English yew on the forest level may require well-managed reserves and long-term rotations between harvest events, protection from the herbivore and reduction of competition, which will enhance the long-term viability of the species.     

Humoral antibody response in animals infected with virulent rinderpest virus

Summary Humoral antibody responses in cattle or rabbits infected with virulent rinderpest virus or lapinised rinderpest virus respectively were assessed. Rinderpest specific antibodies could be first detected 6 days post-infection. No correlation could be established between antibody response and the course of the disease in infected animals during the early stages of infection. The animals with fatal infection either did not respond or had a transient antibody response. A gradual increase in antibody titre from 7 days post-infection was observed in animals which ultimately recovered.

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Respuesta De Anticuerpos Humorales En Animales Infectados Con Virus Virulento De Rinderpest

Resumen Se llevó a cabo un estudio tendiente a captar la respuesta de anticuerpos humorales en bovinos o conejos infectados con virus virulento de rinderpest o virus lapinizado de rinderpest, respectivamente. Los anticuerpos específicos de rinderpest fueron detectados a partir de los 6 días despues de la inoculación. No se pudo establecer correlación entre la respuesta de anticuerpos y el curso de la enfermedad en animales infectados, durante los estadíos iniciales de la enfermedad. Los animales con infecciones fatales o no respondieron o tuvieron una respuesta humoral débil. Los animales que se recuperaron presentaron un alza progresiva en el nivel de anticuerpos desde los 7 días después de la infección.

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Response Immunitaire Humorale Chez Des Animaux Infectes Par Le Virus De La Peste Bovine

Résumé Les réponses immunitaires de bovines ou lapins infectés respectivement par le virus de la peste bovine virulent ou lapinisé ont été évaluées. Des anticorps spécifiques contre la peste bovine ont pu être décelés 6 jours après l'infection. Aucune corrélation n'a pu être établie entre la réponse immunitaire et l'évolution de la maladie chez les animaux durant les premiers stades de l'infection. Les animaux n'ayant pas survécu soit n'ont pas développé une réponse immunitaire soit l'on présentée mais de façon transitoire. Une augmentation graduelle de taux d'anticorps à partir du 7e jour après l'infection a été observée chez les animaux qui ont fini par guérir.

     

Recurrent somatic embryogenesis and plant regeneration in Angelica glauca Edgew., a critically endangered medicinal plant of the Western Himalaya

Summary

Secondary somatic embryogenesis and plant regeneration from seedling explants of Angelica glauca, an endangered medicinal plant of the Himalaya, is reported for the first time. Callus was obtained from all the explants tested in the present study (i.e., epicotyls, hypocotyls, and cotyledonary nodes). The highest frequency of callus formation (95.8%) was observed using epicotyl explants on 4.0 µM 2,4-dichlorophenoxyacetic acid (2,4-D), whereas 70.8% of hypocotyl explants, and 58.3% of cotyledonary nodes produced callus. One-hundred percent embryogenic callus was induced from epicotyl explants in 2.0 µM 6-benzyladenine (BA) and 2.0 µM μnaphthaleneacetic acid (NAA), together with the maximum number of somatic embryos (34.2 embryos per explant). Cotyledonary nodes did not produce somatic embryos. Histological studies confirmed the induction of somatic embryogenesis. Somatic embryos germinated into plantlets upon transfer to half-strength Murashige and Skoog (MS) medium without added plant growth regulators. We observed 85% survival of these plantlets under field conditions. The development of secondary embryos was also observed when primary embryos were sub-cultured on full-strength MS medium containing 2.0 µM NAA plus 2.0 µM BA. This system of recurrent somatic embryogenesis provides a route for gene transfer and also for the large-scale production of this critically endangered medicinal plant.     

Synthesis of new 7H-1,3,4-thiadiazolo[3,2-a] [1,3,5] triazine-7-thiones as potential fungicides

A number of 2-aryl- and 2-aryloxymethyl-5-aryl-7H-1,3,4-thiadiazolo[3,2-a][1,3,5]triazine-7-thiones have been synthesised and their fungitoxicities determined in vitro against Aspergillus niger and Fusarium oxysporum. Two alternative routes for synthesis of the title compounds are described. Some of the compounds had activities comparable with that of the commercial fungicide mancozeb. Structure/activity relationships for the compounds are discussed.     

Marek's disease virus-transformed chicken T-cell lines respond to lymphokines.

Current assays for chicken interleukin-2 (IL-2) utilize mitogen-activated lymphocytes. However, very high inter-assay variability and sporadic high background proliferation limit their usefulness. In view of the above, several Marek's disease virus (MDV)-transformed T-cell lines (which grow well in a serum-supplemented medium) were tested for a response to chicken IL-2 when grown in serum-free media. Five of six lines examined showed a dose-dependent proliferative response to chicken T-cell conditioned media. One line, MDCC-CU14, was chosen for further studies. In addition to the tumor cells' dose-dependent responses to semi-purified chicken IL-2, they expressed T-cell activation antigens on the cell surface. Furthermore, the level of surface expression was enhanced on cells provided IL-2. Co-incubation of the tumor cells with monoclonal antibody INN-CH-16 (specific for an antigen on the surface of activated T-cells) and IL-2 resulted in a modulation of lymphokine-induced proliferation. Together, these data suggest that signalling mechanisms in MDV T-cell tumors are intact and that these lines can be used as an assay for chicken T-cell lymphokines. Furthermore, they provide an interesting model for the study of avian and mammalian T-cell transformation. Implications for the study of Marek's disease are also discussed.     

Genetic parameters of survival in four generations of Indian white shrimp (Fenneropeneaus indicus)

This study evaluated the genetic variance for survival at harvest of Indian white shrimp (Fenneropenaeus indicus) using a pedigreed synthetic population generated upon collecting broodstock from different fishery grounds in Egypt. The estimated heritabilities (h² ± SE) of survival from generations G₀ to G₃ ranged from 0.144 ± 0.026 to 0.008 ± 0.030 using a model that included the common environmental effect (c²). Low heritability (0.014 ± 0.015) was estimated across generations with the inclusion of common environmental effect (c²). However, the h² of survival from G₀ to G₁ ranged from 0.569 ± 0.071 to 0.410 ± 0.011 when c² was not included. The genetic correlation for survival between different ponds from G₀ to G₃ was moderate to high (0.79 ± 0.042 to 0.83 ± 0.012) but significantly different (P < 0.05). There were low correlation coefficients (?0.237 ± 0.089 to 0.316 ± 0.073) between body weight estimated breeding value (EBV) and survival EBV of families in four generations.     

Assessment of transmission risk in WSSV-infected shrimp Litopenaeus vannamei upon cooking

White spot syndrome virus has been a threat to the global shrimp industry since it was discovered in Taiwan in 1992. Thus, shrimp-producing countries have launched regulations to prevent import of WSSV-infected commodity shrimp from endemic areas. Recently, cooked shrimp that is infected with WSSV tested positive by PCR. However, there is no study to determine the infectivity of WSSV in cooked shrimp that tested positive by PCR. In the present study, WSSV-infected shrimp were cooked at boiling temperature for different times including 0, 1, 3, 5, 10 and 30 min. Upon exposure to boiling temperature, WSSV-infected shrimp were fed to SPF shrimp (Litopenaeus vannamei). The result showed experimentally challenged shrimp from 0-min treatment (positive control) indeed got infected with WSSV. However, experimentally challenged shrimp that were fed tissues boiled at 1, 3, 5, 10 and 30 min were not infected with WSSV. Mortality data showed that only the positive control (0-min) treatment displayed high mortality, whereas no mortality was observed in any other treatment category. These findings suggest that cooking shrimp at boiling temperature for at least 1 min might prevent any potential spread of WSSV from endemic countries to other geographical areas where WSSV has not yet been reported.     

Identification of water-stressed area based on the interrelationship of soil moisture and seasonal rice cultivation

Paddy and Water Environment - The present study identifies water-stressed areas based on linkages between NOAH model-based soil moisture and seasonal paddy rice cultivation in the...