Report on the 43rd Annual Meeting of the DPG-Working Group Nematology

Journal of Plant Diseases and Protection -     

Use of molasses as a carbon source during the nursery rearing of Farfantepenaeus brasiliensis (Latreille, 1817) in a Biofloc technology system

The present work evaluated the use of molasses as a carbon source during the nursery rearing of Farfantepenaeus brasiliensis in a Biofloc technology system. During a 30 days trial, three replicate tanks were randomly assigned to the following treatments: 1.) molasses (with molasses addition) and 2.) control (without molasses addition). Bacteriological analysis was used to quantify the abundance of presumptive Vibrio spp. between control and molasses treatment. The concentration of this microorganism was lower in molasses compared with control. For the immunological analysis, shrimp haemolymph was collected to determine the total haemocyte count and the total protein concentration. The immunological results were not different between treatments. The performance results of shrimp reared with molasses addition showed that the survival rate (88.87 ± 6.36), the mean final weight (1.22 ± 0.38) and the specific growth rate (0.0309 ± 1.06) were significantly higher compared with control (80.5 ± 2.42; 1.03 ± 0.13; 0.0256 ± 0.97 respectively). Moreover, the addition of molasses contributed to the maintenance of water quality and lower concentration of presumptive Vibrio spp. The control presented an unstable variation of Vibrio spp. reaching values of 80 × 10² CFU/ml, while the highest result of molasses was 20 × 10² CFU/ml, confirming the beneficial effects of molasses addition.     

The impact of sea erosion on coastal Pinus pinea stands: A diachronic analysis combining tree-rings and ecological markers

Coastal erosion is a widespread phenomenon on sandy coasts throughout the Mediterranean region; along the Thyrrenian coast of Tuscany (Italy), stone pine (Pinus pinea L.) stands originally planted for the protection of agricultural crops further inland are often damaged. In the present study, a pairwise comparison of stands at different distance from the sea at eroded and control sites highlighted the effects of coastal erosion alone on pine growth and function. Dendroecological analyses made it possible to determine the temporal dynamics of the phenomenon since 1930 and the interactions with climate, whilst additional structural (LAI, sapwood area) and functional (carbon isotope discrimination) measurements were used to discriminate between stress mechanisms. Salty winds, exacerbated by the removal of dunal vegetation, were found to be the most likely cause of the observed growth decline. The presence and, in more recent times, the reduction of surfactants in sea water played an important synergistic effect. The intrusion of salty water in the water table, on the contrary, played a marginal role at the site. Finally, stressed trees were more sensitive to the inter-annual variability in precipitation; at all sites, growth was stimulated by June, November and December precipitation in the current and two preceding years.     

Release of doxycycline through cellulose acetate symmetric and asymmetric membranes produced from recycled agroindustrial residue: Sugarcane bagasse

Cellulose acetate is one of the components employed in drug controlled-release systems in the form of membranes. The aim of this study was to examine the controlled-release of doxycycline employing cellulose acetate symmetric and asymmetric membranes as matrices. The cellulose triacetate was produced from sugarcane bagasse through a homogeneous acetylation reaction, using acetic acid as the solvent, acetic anhydride as the acetylating agent and sulfuric acid as the catalyst. The viscosity average molecular weight of the cellulose acetate produced was 39,000 g mol⁻¹. The symmetric membranes were produced using a system solvent of dichloromethane/ethanol (9:1, v/v) and the asymmetric membranes were produced from the same solvent system and 10% of water. For the formulation of both, 5% of doxycycline was used. The membranes were characterized by thermal analysis (DSC and TGA) and scanning electron microscopy SEM. The release of doxycycline through cellulose triacetate matrices was examined using spectrophotometric analysis in the ultraviolet-visible region, at 275 nm. The results revealed that asymmetric membranes release 80% of the drug in 100 min, while symmetric membranes release 14% of the drug during the same time interval.     

IMAGING DIAGNOSIS—ULTRASONOGRAPHIC APPEARANCE OF SKELETAL MUSCLE METASTASES IN A DOG WITH HEMANGIOSARCOMA

A 13‐year‐old spayed female German shepherd dog was presented for acute onset of lethargy, anorexia, and disseminated erythematous skin lesions. Thoracic radiographs and abdominal ultrasonographic findings were consistent with metastatic hemangiosarcoma. Multiple, ill‐defined, irregularly shaped hypoechoic nodules were also detected within the thoracic and abdominal wall. Hemangiosarcoma metastases to the skeletal muscle were confirmed based on histopathological examination. Multivisceral involvement was also confirmed by necropsy. Metastatic neoplasia should be considered as a differential diagnosis for dogs with ill‐defined, irregular, hypoechoic, intramuscular nodules.     

Monitoring neonicotinoid resistance in biotype B of Bemisia tabaci in Florida

BACKGROUND: Biotype B of the sweetpotato whitefly, Bemisia tabaci (Genn.), is a worldwide pest that has developed resistance to many insecticides, including the neonicotinoid class. Florida field populations were monitored for susceptibility to the neonicotinoids imidacloprid and thiamethoxam using a cut leaf petiole bioassay method. RESULTS: Average RR₅₀ values for imidacloprid increased from 3.7 in 2000 to 12.0 in 2003; decreased to 5.0 and 2.5 in 2004 and 2005, respectively; and then increased to 26.3 and 23.9 in 2006 and 2007, respectively. Populations with RR₅₀ values of about 50 to 60 during generation one reverted to RR₅₀ values of ?4 in six generations, when reared without further exposure to imidacloprid. Average RR₅₀ values for thiamethoxam increased from 2.0 in 2003 to 24.7 in 2006 and decreased to 10.4 in 2007. Populations with RR₅₀ values of about 22, 32 and 53 during generation one declined to 8, 5 and 6, respectively, after being reared for five generations without exposure to thiamethoxam. The correlation coefficient from the 26 populations that were bioassayed both with imidacloprid and thiamethoxam showed a significant positive correlation (R² = 0.58) between these populations. CONCLUSION: The high level of RR₅₀ values to imidacloprid and thiamethoxam suggest an unstable decline in the susceptibility of B. tabaci to imidacloprid and thiamethoxam, with possible cross‐resistance or predisposition for dual resistance selection. Copyright © 2009 Society of Chemical Industry     

Effect of food on the pharmacokinetics of oral cefuroxime axetil in dogs

Cefuroxime axetil pharmacokinetic profile was investigated in 12 Beagle dogs after single intravenous and oral administration of tablets or suspension at a dose of 20 mg/kg, under both fasting and fed conditions. A three-period, three-treatment crossover study (IV, PO under fasting and fed condition) was applied. Blood samples were withdrawn at predetermined times over a 12-hr period. Cefuroxime plasma concentrations were determined by HPLC. Data were analyzed by compartmental analysis. No statistically significant differences were observed between formulations and feeding conditions on PK parameters. Independently of the feeding condition, absorption of cefuroxime axetil after tablet administration was low and erratic. The drug has been quantified in plasma in 3 out of 6 and 5 out of 6 dogs in the fasted and fed groups. For this formulation, the bioavailability (F), peak plasma concentration (C_max), and area under the concentration–time curve (AUC) of cefuroxime axetil were significantly enhanced (p < .05) by the concomitant ingestion of food (32.97 ± 13.47–14.08 ± 7.79%, 6.30 ± 2.62–2.74 ± 0.66 µg/ml, and 15.75 ± 3.98–7.82 ± 2.76 µg.hr/ml for F, C_max, and AUC in fed and fasted dogs, respectively), while for cefuroxime axetil suspension, feeding conditions affected only the rate of absorption, as reflected by the significantly shorter absorption half-life (T_½(a)) and time to peak concentration (T_max) (0.55 ± 0.27–1.15 ± 0.19 hr and 1.21 ± 0.22–1.70 ± 0.30 for T_½(a) and T_max in fed and fasted dogs, respectively). For cefuroxime axetil tablets, T > MIC (≤1 µg/ml) was <2 hr in fasted and ≈4 hr in fed animals, and for cefuroxime axetil suspension, T > MIC (≤1 µg/ml) was ≈5 hr and for T >MIC (≤4 µg/ml) was ≈2.5 hr for fasted and fed dogs, respectively. Cefuroxime axetil as a suspension formulation seems to be a better option than tablets. However, its short permanence in plasma could reduce its clinical usefulness in dogs.