FC‐14 Clonality studies of feline cutaneous lymphocytosis

A previous study described cutaneous lymphocytosis (CL) in 23 cats. The process resembles cutaneous pseudolymphoma in humans, a heterogeneous group of benign reactive proliferations of well‐differentiated lymphocytes in the skin of humans. Morphological and immunophenotypic characteristics do not offer reliable criteria to accurately predict the clinical outcome of feline CL or pseudolymphoma in humans. Presence of clonal cell populations is more consistent with a neoplastic process. In a previous study, feline CL lesions (20 cats) were evaluated for clonality using PCR, and only two cats had monoclonal T‐cell populations. Because false‐negative results may occur, the purpose of this study was to repeat the PCR using a revised primer set based on analysis of additional feline T‐cell receptor γ (TCRγ) sequences. DNA was isolated from 29 skin lesions and six internal organs of 20 cats. DNA integrity was assessed by glyceraldehyde‐3‐phosphate dehydrogenase PCR. Polymerase chain reaction clonality was performed using the revised primer set specific for feline TCRγ, and duplicate samples were evaluated. The PCR products were assessed by heteroduplex analysis. Clonal rearrangement of TCRγ was detected in 14 cats (24 of 35 tissues: 21 of 29 skin lesions and three of six internal organs); eight of these cats are still alive and six were euthanized. Monoclonal populations were seen in three of five cats that had involvement of internal organs. These findings indicate that feline CL is best considered as a slowly progressive process which may be reactive, but often evolves into a low‐grade indolent lymphoma. Funding: George H. Muller Fund for Research in Dermatology.     

Hyperglycaemia in transition dairy cows: Effects of lactational stage and conjugated linoleic acid supplementation on glucose metabolism and turnover

Supplementing conjugated linoleic acid ( CLA ) is supposed to spare glucose due to the milk fat‐depressing effect of the trans ‐10, cis ‐12 CLA isomer, and allows repartitioning nutrients despite an energy deficiency in early lactation. However, there is still a lack of knowledge in terms of the dynamic pattern of the glucose turnover in transition dairy cows. We hypothesized that dairy cows supplemented with CLA have an altered rate of glucose turnover and insulin sensitivity during early lactation. We conducted three consecutive hyperglycaemic clamps (HGC ) in weeks ?2, +2 and +4 relative to parturition in Holstein cows supplemented daily either with 70 g of lipid‐encapsulated CLA (6.8 g trans ‐10, cis ‐12 and 6.6 g of the cis ‐9, trans ‐11 CLA isomer; CLA ; n  = 11) or with 56 g of control fat ( CON ; n  = 11). From week ?3 up to week +4 relative to parturition, milk yield and dry matter intake (DMI ) were recorded daily, while body weight (BW ) and milk composition were obtained once weekly. Blood samples were taken once weekly and every 30 min during the HGC . Plasma was analysed for concentrations of glucose, fatty acids (FFA ), beta‐hydroxybutyrate (BHB ), insulin, triglycerides and cholesterol. The CLA supplementation did not affect performance and metabolic parameters except for BHB and cholesterol. Furthermore, insulin concentrations and insulin sensitivity were affected by treatment. During the HGC in early lactation, insulin response was lower and decrease in FFA and BHB greater compared with the HGC in week ?2 although glucose target concentration achieved during the steady‐state period was similar for all three HGC . Our findings in terms of insulin and cholesterol suggest that body reserves are preserved through CLA feeding without restraining animal's performance. Furthermore, CLA effects on cholesterol and triglyceride concentrations indicated beneficial effects on hepatic lipid export contributing to an improved efficiency of prevailing metabolites in circulation.     

Production of salmonid amoebic gill disease by exposure to Paramoeba sp. harvested from the gills of infected fish

Atlantic salmon, S almo salar L., were exposed to different concentrations of Paramoeba sp. The lowest concentration which induced amoebic gill disease (AGD) was 230 Paramoeba sp. L^–1 and the severity of infection increased with increasing concentration. The concentration of Paramoeba sp. positively correlated with the number of gill lesions ( R ² > 0.7). This study provides evidence that Paramoeba sp. is the causative agent of AGD and describes an experimental model that enables the severity of the induced disease to be controlled.     

Genetic diversity and differentiation of sea trout (<Emphasis Type="Italic">Salmo trutta</Emphasis>) populations in Lithuanian rivers assessed by microsatellite DNA variation

The genetic diversity and differentiation of sea trout were studied in three river basins in Lithuania: Akmena-Dane, Bartuva, and Nemunas. A total of 282 individuals were genotyped at eight microsatellite loci. A similar level of genetic diversity was found in all of the populations studied: mean allelic richness ranged from 3.64 to 5.03, and average expected heterozygosity ranged from 0.588 to 0.721. Significant genetic divergence was observed among the different river basins as well as between populations within the drainages. All pairwise F _ST values were highly significant, ranging from 0.027 to 0.197. The analysis of molecular variance showed rather weak hierarchical population structuring within the Nemunas basin, which may be explained by extensive gene flow among different river basins or, alternatively, reflect the influence of artificial breeding. Information on genetic diversity and differentiation of the Lithuanian sea trout populations will be useful for future management decisions.     

Biocontrol potential of Pseudomonas azotoformans,Serratia marcescens and Trichoderma virens against Fusarium wilt of Dalbergia sissoo

Wilt disease caused by Fusarium solani is a serious constraint to Dalbergia sissoo (shisham) plantations in northern India. In this study, the antagonistic potential of 40 bacterial isolates recovered from rhizophere soil of healthy shisham trees, and a well‐characterized Trichoderma species (Trichoderma virens) were tested for their possibility as biocontrol agents for F. solani. Two promising isolates (S1 and S15) were identified which inhibited pathogen growth, caused chitin degradation, produced siderophores and solubilized phosphate in vitro. Isolate S15 scored highest for hydrogen cyanide (HCN) production while isolate S1 was a non‐HCN producer. These two isolates were identified as Serratia marcescens (S1) and Pseudomonas azotoformans (S15) following sequence analysis of 16S rDNA. In dual culture assays, T. virens caused 80% inhibition of mycelial growth of the test fungus. The three selected antagonists when tested in planta in the glasshouse completely suppressed production of wilt symptoms on 12‐month‐old shisham plants. Further work is needed to ascertain the potential of these isolates to be used as biocontrol agents to manage shisham wilt under field conditions.