Botrytis cinerea Infection of Grape Flowers: Light and Electron Microscopical Studies of Infection Sites

ABSTRACT Specific floral organs including the calyptra, stigma, and receptacle area of glasshouse-grown grapevines (Vitis vinifera cv. Cabernet Sauvignon) were inoculated with aqueous suspensions of Botrytis cinerea conidia, and the initial steps involved in colonization and infection of the host tissues were studied for several days postinoculation using light microscopy as well as scanning and transmission electron microscopy. Conidia germinated on all floral organs examined and became attached to the host surface within 48 h after inoculation. However, in all cases the vast majority of conidia accumulated in a channel-like gap between the ovary and the calyx that extended in a narrowing fashion into the flower interior where the ovary joined the receptacle. Very few conidial germ tubes were detected in the style following inoculation of the stigma, and no evidence for their growth toward the ovaries could be found. In contrast, hyphae were more abundant in the receptacle area, regardless of the site of inoculation. Tips of the calyx became necrotic and mycelium formed in the gap between ovary and calyx within 72 h following inoculation, providing a major point of colonization and infection. B. cinerea colonized dehiscent calyptras within 72 h of inoculation, providing a potential source of inoculum from calyptras that remained stuck in the cluster. The results suggest that the grape flower's receptacle area is the predominant site of infection for B. cinerea, although a minor portion of infections may also occur through the stigma and style.     

Tibial plateau symmetry and the effect of osteophytosis on tibial plateau angle measurements

A novel technique was developed to estimate the caudal medial tibial plateau landmark in the face of osteophytosis to improve accuracy in tibial plateau angle measurements. Using this technique, tibial plateau angles were evaluated in 31 normal dogs before and 8 months after right cranial cruciate ligament transection. There was no significant difference in mean tibial plateau angle before or after induction of osteophytosis. Additionally, it was determined that 90% of dogs had a difference of =2 degrees between right and left tibial plateau angles, which was considered symmetrical.     

INTRA- AND INTEROBSERVER VARIABILITY OF ULTRASONOGRAPHIC MEASUREMENTS OF THE THYROID GLAND IN HEALTHY BEAGLES

The repeatability of ultrasonographic measurements of the canine thyroid gland was evaluated. The variability of three different parameters (the maximal length, width, and height) within observer, between observer and between dogs was assessed based on three different measurements made by each of three observers infive healthy beagle dogs. From the three parameters, the volume of the gland was estimated using a formula of a rotation ellipse. The height and the volume had the lowest intra- and interobserver variability, while measurements of the length had the biggest intra- and interobserver variability. The mean values, with their 90% confidence interval were: height = 0.53cm [0.33-0.73], length = 2.45cm [2.04-2.85], width = 0.62cm [0.46- 0.78], volume = 0.38 cm3 [0.20-0.55].     

Floristic diversity and vegetation patterns along disturbance gradient in arid coasts in southern Mediterranean: Case of the Gulf of Gabès,southern Tunisia

Knowledge about vegetation patterns along disturbance gradients is essential for conservation and management of coastal habitats in arid regions. This study focuses on the floristic diversity and the factors controlling the vegetation structure in the Gulf of Gabès (Tunisia). For this purpose, the floristic diversity of 120 relevés belonging to three coastal sites with different disturbance levels (40 relevés per site) was analyzed in relation with 10 environmental and anthropogenic factors. Therophytes constitute 54% of the 237 plants species belonging to 44 families identified in the present study. The species richness and floristic diversity indices exhibited a similar trend and peaked in the slightly disturbed site (H′?=?3.38; S?=?176). The similarity between sites was relatively low and reached its maximum between the little and the highly disturbed sites. Two-way indicator species analysis and detrended correspondence analysis applied on the floristic data resulted in groups mainly determined by disturbance level by explicitly segregating the three sites. Canonical correspondence analysis (CCA) indicated that the spatial pattern of species composition was mainly influenced by anthropogenic variables. Partial CCA revealed that the effect of anthropogenic variables on floristic composition was thrice higher than the effect of environmental variables (57.5% vs. 18.4%, respectively). Overall, this study provides a broad understanding of the floristic diversity and vascular plant richness in the Gulf of Gabès. The obtained results reflected a disturbance–diversity pattern and thus revealed the obvious importance of maintaining the intermediate disturbance for biodiversity conservation and monitoring.     

A high-resolution radiation hybrid map of the human genome draft sequence

We have constructed a physical map of the human genome by using a panel of 90 whole-genome radiation hybrids (the TNG panel) in conjunction with 40,322 sequence-tagged sites (STSs) derived from random genomic sequences as well as expressed sequences. Of 36,678 STSs on the TNG radiation hybrid map, only 3604 (9.8%) were absent from the unassembled draft sequence of the human genome. Of 20,030 STSs ordered on the TNG map as well as the assembled human genome draft sequence and the Celera assembled human genome sequence, 36% of the STSs had a discrepant order between the working draft sequence and the Celera sequence. The TNG map order was identical to one of the two sequence orders in 60% of these discrepant cases.     

Isolation of viral haemorrhagic septicaemia virus from mummichog, stickleback, striped bass and brown trout in eastern Canada

Viral haemorrhagic septicaemia virus (VHSV) was isolated from mortalities occurring in populations of mummichog, Fundulus heteroclitus, stickleback, Gasterosteus aculeatus aculeatus, brown trout, Salmo trutta, and striped bass, Morone saxatilis, in New Brunswick and Nova Scotia, Canada. The isolated viral strains produced a cytopathic effect on the epithelioma papillosum cyprini cell line. Serum neutralization indicated the virus was VHSV and sequencing identified the rhabdovirus isolates as the North American strain of VHSV. Phylogenetic analysis indicated that the isolates are closely related and form a distinguishable subgroup of North American type VHSV. To our knowledge, this is the first report of VHSV in mummichog and striped bass.     

Physiological response,blood chemistry profile and mucus secretion of red sea bream (<Emphasis Type="Italic">Pagrus major</Emphasis>) fed diets supplemented with <Emphasis Type="Italic">Lactobacillus rhamnosus</Emphasis> under low salinity stress

Environmental stressors caused by inadequate aquaculture management strategies suppress the immune response of fish and make them more susceptible to diseases. Therefore, efforts have been made to relieve stress in fish by using various functional feed additives in the diet, including probiotics. The present work evaluates the effects of Lactobacillus rhamnosus (LR) on physiological stress response, blood chemistry and mucus secretion of red sea bream (Pagrus major) under low salinity stress. Fish were fed four diets supplemented with LR at [0 (LR0), 1 × 10² (LR1), 1 × 10⁴ (LR2) and 1 × 10⁶ (LR3) cells g^?1] for 56 days. Before stress, blood cortisol, urea nitrogen (BUN) and total bilirubin (T-BIL) showed no significant difference (P > 0.05), whereas plasma glucose and triglyceride (TG) of fish-fed LR2 and LR3 diets were significantly lower (P < 0.05) than those of the other groups. Plasma total cholesterol (T-CHO) of fish-fed LR3 diet was significantly (P < 0.05) lower than that of the other groups. Furthermore, total plasma protein, mucus myeloperoxidase activity and the amount of mucus secretion were significantly enhanced in LR-supplemented groups when compared with the control group (P < 0.05). After the application of the low salinity stress test, plasma cortisol, glucose, T-CHO and TG contents in all groups showed an increased trend significantly (P < 0.01) compared to the fish before the stress challenge. However, plasma total protein and the amount of secreted mucus showed a decreased trend in all groups. On the other hand, BUN, T-BIL and mucus myeloperoxidase activity showed no significant difference after exposure to the low salinity stress (P > 0.05). In addition, the fish that received LR-supplemented diets showed significantly higher tolerance against low salinity stress than the fish-fed LR-free diet (P < 0.05). The physiological status and the detected immune responses, including total plasma protein and mucus myeloperoxidase activity in red sea bream, will provide a more comprehensive outlook of the effects of probiotics to relieve stress in fish.     

Comparison of the anthocyanin composition during ripening of Syrah grapes grown using organic or conventional agricultural practices

The anthocyanin composition of Syrah grapes harvested at different stages of ripening and produced using organic or conventional agriculture was studied. Samples of grapes were collected from veraison to full maturity in each plot, and the content in nine anthocyanins was determined by high-performance liquid chromatography with diode array detection. The total content in anthocyanins during ripening of the conventionally grown grapes was significantly higher compared to that found in the organic production. The accumulation of anthocyanins reached a maximum 28 days after veraison (in agreement with high temperature) and then decreased until harvest. In all samples, grapes from the conventional agriculture presented higher proportions of delphinidin, petunidin, malvidin, and acylated malvidin glucosides compared to grapes from organic agriculture. In contrast with other comparative studies of organically and conventionally grown plants, the results demonstrated a higher content in anthocyanins in conventionally grown grapes.     

Botrytis cinerea Infection in Grape Flowers: Defense Reaction, Latency, and Disease Expression

ABSTRACT Inflorescences of field-grown grapevines (Vitis vinifera L. cv. Gamay) were inoculated with a Botrytis cinerea conidia suspension or dried conidia at different stages during bloom in moist weather. Approximately 10% of the conidia germinated within 72 h, resulting in two to three times more latent infections than uninoculated controls in pea-size (7 mm in diameter) berries. In surface-sterilized pea-size berries, latent B. cinerea was present predominantly in the receptacle area. After veraison, latent B. cinerea also was found in the style and, in mature berries, latent colonies were distributed throughout the pulp. Inoculation at full bloom led to the highest disease severity (66%) at harvest, compared with 38% in controls. Stilbene stress metabolites in the flowers were measured by high-performance liquid chromatography. Resveratrol accumulated mainly after pre-bloom and full-bloom inoculation, but did not prevent infection. Piceid levels did not change following inoculation, while epsilon-viniferin was found in necrotic tissues only, and pterostilbene and alphaviniferin were not detected at all. B. cinerea conidia suspensions also were applied to various locations on flowers of pot-grown cvs. Pinot Noir and Chardonnay. Inoculation of the receptacle area, but not that of the stigma and ovary, resulted in latent infections. Stilbene synthesis was similar to the field results, with resveratrol accumulating mainly in the calyptra and receptacle area. Constitutive soluble phenolic compounds (mainly derivatives of quercetin and hydroxy-cinnamic acid) were present at high concentrations in the calyptra but at low levels in the receptacle area. These experiments confirmed bloom as a critical time for B. cinerea infection in grapes and suggest that the most likely site of infection is the receptacle area or cap scar exposed at anthesis. Stilbenes may have a limited role in inhibition of flower infection and latency in susceptible grape cultivars, and epsilon-viniferin may be a by-product rather than a deterrent of infection.