Screening techniques and sources of resistance to root diseases in cool season food legumes

Summary Soil-borne fungal diseases are among the most important factors, limiting the yield of grain legumes in many countries worldwide. Root rot, caused by Aphanomyces euteiches, Rhizoctonia solani, Fusarium solani and wilt, caused by several formae speciales of Fusarium oxysporum are the most destructive soil-borne diseases of pea, chickpea, lentil, fababean and lupin. The most effective control of these diseases is achieved through the use of resistant varieties. In this paper, recent advances in conventional and innovative screening methods for disease resistance are presented. Many grain legume accessions, which are maintained in national and international germplasm collections, have been evaluated for disease resistance and numerous resistant varieties have been released following incorporation of identified resistance genes from these sources. Recent identification of molecular markers tightly linked to resistance genes has greatly enhanced breeding programs by making marker assisted selection (MAS) possible and allowing the development of varieties with multiple disease resistance. Progress in the understanding of the biology of soil-borne fungal pathogens of grain legumes is also reviewed with particular reference to the genetic structure of their populations, diagnosis and host–pathogen interaction.     

Application of biotechnology in breeding lentil for resistance to biotic and abiotic stress

Summary Lentil is a self-pollinating diploid (2n = 14 chromosomes) annual cool season legume crop that is produced throughout the world and is highly valued as a high protein food. Several abiotic stresses are important to lentil yields world wide and include drought, heat, salt susceptibility and iron deficiency. The biotic stresses are numerous and include: susceptibility to Ascochyta blight, caused by Ascochyta lentis; Anthracnose, caused by Colletotrichum truncatum; Fusarium wilt, caused by Fusarium oxysporum; Sclerotinia white mold, caused by Sclerotinia sclerotiorum; rust, caused by Uromyces fabae; and numerous aphid transmitted viruses. Lentil is also highly susceptible to several species of Orabanche prevalent in the Mediterranean region, for which there does not appear to be much resistance in the germplasm. Plant breeders and geneticists have addressed these stresses by identifying resistant/tolerant germplasm, determining the genetics involved and the genetic map positions of the resistant genes. To this end progress has been made in mapping the lentil genome and several genetic maps are available that eventually will lead to the development of a consensus map for lentil. Marker density has been limited in the published genetic maps and there is a distinct lack of co-dominant markers that would facilitate comparisons of the available genetic maps and efficient identification of markers closely linked to genes of interest. Molecular breeding of lentil for disease resistance genes using marker assisted selection, particularly for resistance to Ascochyta blight and Anthracnose, is underway in Australia and Canada and promising results have been obtained. Comparative genomics and synteny analyses with closely related legumes promises to further advance the knowledge of the lentil genome and provide lentil breeders with additional genes and selectable markers for use in marker assisted selection. Genomic tools such as macro and micro arrays, reverse genetics and genetic transformation are emerging technologies that may eventually be available for use in lentil crop improvement.     

Occurrence of Mycobacterium spp. and other pathogens in lymph nodes of slaughtered swine and wild boars (Sus scrofa)

Mycobacterium spp. and other pathogens were investigated in 258 swine lymph nodes (129 with and 129 without apparent lesions), and 120 lymph nodes (60 with and 60 without lesions) from wild boars (Sus scrofa). A total of lymph nodes from swine and wild boars were collected of different animals. Submaxillar and mesenteric lymph nodes were submitted to microbiological examination and colonies suggestive of Mycobacterium spp. (alcohol-acid bacilli) were submitted to PCR Restriction Assay (PRA). In swine with lymphadenitis, Mycobacterium spp. (24.1%) and Rhodococcus equi (13.2%) were the most prevalent microorganisms, while in lymph nodes without lesions were identified a complex of microorganisms, including of environmental mycobacteria. In wild boars with lymphadenitis, ß-haemolytic Streptococcus (10.0%), Mycobacterium spp (8.4%) and R. equi (6.6%) were the most frequent. Among mycobacterias were identified predominantly Mycobacterium avium subspecies type 1 (48.3%) and M. avium subspecies type 2 (16.1%), followed by Mycobacterium intracellulare, Mycobacterium szulgai,Mycobacterium fortuitum, Mycobacterium gordonae, Mycobacterium simiae, Mycobacterium nonchromogenicum and Mycobacterium intracellulare type 2.     

Survival of silver catfish fingerlings exposed to acute changes of water pH and hardness

Theaim of this study was to examine the survival of fingerlings of silver catfish,Rhamdia quelen, in water with different pH and hardnessvalues. Fingerlings (1.60 ± 0.14 g; 5.67 ± 0.15cm) were randomly assigned to 35 treatments (in triplicate) andmaintained in 44 L polyethylene tanks (10 fingerlings/tank) for 96h. Fingerlings were exposed to seven solutions of varying pH (3.5,3.75, 4.0, 7.0, 9.5, 10.0, and 10.5) and five solutions of varying hardness(30,70, 150, 300, and 600 mg.l^?1 CaCO₃).Survival was assessed at 12, 24, 48, 72, and 96 h. Fingerlingmortality was 100% after 12 h exposure to pH 3.5 at all hardnesslevels, whereas mortality at pH 3.75, 10.0, and 10.5 decreased with increasinghardness. There was no mortality of fingerlings exposed to pH 4.0, 7.0, and 9.5at all hardness levels. The results allow us to conclude that the hardnesslevels studied do not affect the survival of silver catfish fingerlings exposedto pH 3.5, 4.0, 7.0, and 9.5 for 96 h. However, the increase ofwater hardness improved survival of fingerlings of this species exposed to pH3.75, 10.0, and 10.5.     

Ventricular septal defect repair in a small dog using cross-circulation

SUMMARY A haemodynamically significant ventricular septal defect was diagnosed in a 3-month-old male Cavalier King Charles Spaniel. A median sternotomy was performed and the 6.5 kg dog placed on cardiopulmonary bypass using pump-assisted cross-circulation. A 10 mm diameter peri-membranous ventricular septal defect was closed using a continuous suture of 4–0 polypropylene, via a 2.5 cm incision in the right ventricular outflow tract. The duration of cardiopulmonary bypass was 90 minutes. Complications in the immediate postoperative period were mild and easily managed.     

Intracerebroventricular Infusion of Leptin into Mature Merino Rams of Different Metabolic Status: Effects on Blood Concentrations of Glucose and Reproductive and Metabolic Hormones

In mature Merino rams, nutrition is one of the external cues that most strongly affects the reproductive centres of the preoptic-hypothalamic continuum. The signalling pathways that link dietary status and the activity of the neurones that produce gonadotrophin-releasing hormone signals are thought to be partly hormonal in nature to reflect the amount of body reserves. Among the hormones thought to be involved are insulin and leptin. This study tested whether recombinant bovine leptin infused (0.4 microg/h) into the third cerebral ventricle would stimulate pulsatile luteinizing hormone (LH) secretion in mature Merino rams when their energy status was low or decreasing, during both chronic (fasting) and acute reductions of energy balance. Leptin may interact with other hormones that depend on energy availability, so we also monitored changes in circulating concentrations of insulin, thyroid hormones, growth hormone, prolactin and adrenocorticotrophin. Overall, our data do not support this hypothesis. The dietary regimes induced clear responses in the metabolic profiles of the animals but there was no clear effect of central leptin administration on LH pulse frequency. The relationships between the hormonal systems measured in the present study add weight to the contention that leptin plays only a permissive role in the nutritional control of the reproductive axis and that other hormonal signals (particularly insulin) or pathways are acting in concert with leptin to stimulate the reproductive axis.