Chitinases of Trichoderma atroviride Induce Scab Resistance and Some Metabolic Changes in Two Cultivars of Apple

ABSTRACT This study reports the combination of a transgene-mediated defense mechanism with a conventionally bred resistance in order to improve apple scab resistance. Two cultivars of apple (Galaxy, scab-susceptible, and Ariane, carrying the Vf resistance gene) were transformed with endochitinase and exochitinase genes derived from the biocontrol fungus Trichoderma atroviride. The obtained transgenic lines were analyzed for the expression of both genes and resistance to two races of the pathogen Venturia inaequalis: the common race 1 and race 6 which overcomes the resistance conferred by the Vf gene. A negative correlation between growth of transgenic lines and endochitinase activity was observed. Reduced growth appeared to be associated with high lignin content and high peroxidase as well as glucanase activity, suggesting that endochitinase activity may disturb the metabolism of the plant. Scab inoculation with races 1 and 6 performed in a growth chamber on 14 lines of normal vigor identified 6 lines with significantly enhanced resistance. Ten lines with reduced vigor were tested in vitro with a bioassay on rooted shoots. All lines expressing high endochitinase activity exhibited a significant reduction of scab symptoms.     

Fatal necrotizing fasciitis and myositis in a captive common bottlenose dolphin (Tursiops truncatus) associated with Streptococcus agalactiae.

A common bottlenose dolphin (Tursiops truncatus) was presented for necropsy after acute onset of gastrointestinal signs and cutaneous lesions that rapidly progressed to death. Gross and microscopic findings were characterized by locally extensive severe necrohemorrhagic fasciitis and cellulitis, and severe necrotizing myositis in the head and dorsocranial thorax, with numerous disseminated gram-positive cocci. Streptococcus agalactiae was isolated from the lesions and from visceral organs (liver and lung), and it was identified by standard microbiology techniques. This communication is the first report of necrotizing fasciitis in a marine mammal associated with S. agalactiae.     

Environmental and genetic variation of the effective radiative properties of the coat of Holstein cows under tropical conditions

Morphological characteristics, coat effective radiative properties, and the percentage of white colour were measured in the coats of 973 Holstein cows, and estimates of the genetic parameters were obtained for these traits, except morphological characteristics. The results showed that white coats are more dense with long, thin hairs, while the black coats are less dense with short, thick hairs. Effective transmissivity is greater in the less-dense coats with short, thin hairs, independently of coat colour. Effective reflectivity depends more on the variation in the radiative properties of the coat and skin surface rather than on the morphological characteristics of the coat. Effective absorptivity is greater in black and dense coats with long, thick hairs, than in the white and less-dense coat with short, thin hairs. All heritability estimates were of low magnitude, except for the percentage of white coat colour.     

Evidence of Two Formae Speciales in Venturia inaequalis, Responsible for Apple and Pyracantha Scab

ABSTRACT Genetic relationships, mating crosses, and host specificity of Venturia inaequalis isolates from Malus spp. and of Spilocaea pyracanthae isolates from Pyracantha spp. were evaluated. Sequence analysis of the complete internal transcribed spacer (ITS) region (ITS1-5.8S to ITS2) revealed a total similarity between these two putative species. ITS restriction fragment length polymorphism carried out with five restriction enzymes on a collection of 28 isolates confirmed a lack of diversity in this region between and within these two populations. Additional isolates from three related species (V. pirina, V. nashicola, and S. eriobotryae) were divided into two distinct monophyletic groups in a phylogenetic tree using ITS sequence comparison. These groups were related to their anamorph (i.e., Spilocaea or Fusicladium). When inoculated on their host of origin, fields isolates caused typical symptoms of scab disease, and a host specificity was demonstrated by cross pathogenicity of isolates from Malus x domestica and Pyracantha spp. Mating on dried leaves in vitro between one isolate of each putative species led to production of numerous perithecia. Ninety-six sporulating monoascosporic progenies were isolated from this cross. Based on these genetic and pathogenic data, we proposed that pathogens responsible for scab on Malus spp. and Pyracantha spp. are considered as two formae speciales belonging to V. inaequalis.     

Pastoralism and plant cover in the lower Shabelle Region,Southern Somalia

A vegetation and rangeland survey has been carried out in the lower Shabelle region, Southern Somalia, with the aim of evaluating the natural vegetation as a source of forage for grazing animals. In this framework, four different vegetation types have been recognized and mapped using remote sensing techniques; general vegetation characteristics, mainly floristic and physiognomic aspects, are described. Dynamic relationships between these vegetation types are also outlined.     

Suppressive activity of some glucosinolate enzyme degradation products on Pythium irregulare and Rhizoctonia solani in sterile soil

Glucosinolate degradation products (GLDPs), mainly isothiocyanates, obtained by myrosinase‐catalysed hydrolysis of glucosinolates (GLs), are an important group of natural bioactive substances. The fungitoxic activity of four GLDPs, chosen on the basis of their side‐chain structures, was assayed against Pythium irregulare and Rhizoctonia solani. The effectiveness of the degradation products (DPs) of sinigrin (alkenyl GL), epi‐progoitrin (hydroxy‐alkenyl GL), glucoiberin and glucoerucin (thiofunctionalised GLs) in inhibiting P irregulare oospore germination and R solani soil colonisation were tested in a closed system, using an artificially infected soil. The fungitoxic activity of these GLDPs varied according to their side‐chain structure. As in previous in vitro studies, the thiofunctionalised GLDPs were found the most effective, producing complete inhibition of P irregulare oospore germination (0.01 µmole g⁻¹ soil) and R solani soil colonisation (0.5 µmole g⁻¹ soil), but even sinigrin DP showed a fungitoxic activity higher than that of epi‐progoitrin DP. © 2000 Society of Chemical Industry     

Ontogeny of hepatic methionine catabolic enzyme activities (Transmethylation and Transsulphuration) and associated physiological amino acids in E10-21 chick embryos and D1-49 broilers

Developmental changes in hepatic methionine adenosyltransferase, cystathionine β-synthase, cystathionase, and glycine N-methyltransferase were determined in broiler chick embryos and hatched chicks by using radiometric and spectrometric methods. Hepatic free methionine, S-adenosylmethionine, S-adenosylhomocysteine, homocysteine, cystathionine, and cysteine levels were also investigated. Results showed an increase in hepatic MAT activity from E10 to E21 during embryogenesis, suggesting greater transmethylation rates throughout the rapid embryonic growth and development period. A strong positive correlation between embryo BW and MAT activity also supports this idea. The MAT specific activity continued to increase after hatching, but there was a negative correlation between chick BW and MAT activities from D1 to D49. This may indicate different MAT isozymes exist for chick embryo hepatic tissue compared to hepatic tissue of hatched chick and growing broilers. The developmental pattern of MAT isozymes could be critical for methionine metabolism to cope with the demand imposed on the embryo, chicks, and growing broilers. Additionally, the specific activity of hepatic CBS in chick embryos was determined to be lower compared to that observed in older broilers (35 and 49 days). Since liver CBS specific activity is at the lowest point from D1-7 in young chicks, the ability to convert adequate homocysteine to cysteine through transsulphuration may be limiting for cysteine synthesis at this time. Steady-state hepatic homocysteine levels in chick embryos and chicks may be a function of the rates of homocysteine formation, remethylation, and catabolism via the transsulphuration pathway. The present study indicates young chicks from D1 to D7 may have a limited ability for adequate transsulphuration; therefore, dietary cystine may be needed for optimum performance.     

A habitat model for brown bear conservation and land use planning in the central Apennines

We investigated the brown bear habitat suitability in an 8000 km² study area encompassing Abruzzo, Latium, and Molise regions in central-southern Italy. Based on long-term field surveys and published records, we classified bear habitat as occupied or unoccupied in 92 out of 320 sample squares (5 × 5 km). For each sample square 36 habitat variables were measured from topographic maps and Corine land-cover III level digital maps. The influence of habitat features on bear presence was investigated by multivariate and one-way analyses of variance and by logistic regression analysis. The logistic model correctly classified 95.5% of sample squares of bear presence and 93.8% of those where bears were absent. Average altitude, deciduous woodlands and ecotone length, showed a positive relationship with bear presence, whereas vineyard-olive groves and shrublands were negatively correlated with bear presence. No specific land management guidelines or strategies exist for bear conservation in central Italy, based on knowledge of habitat-population relationships. The landscape scale habitat model we developed could be useful to predict bear occurrence, to identify critical areas for a brown bear conservation strategy, and to enhance the arrangement of the protected areas network for the conservation of this species.