Can spleen aspirations be safely used for the parasitological diagnosis of canine visceral leishmaniosis? A study on assymptomatic and polysymptomatic animals

The purpose of this study was to evaluate the safety of spleen aspiration as a sampling technique for the parasitological detection by culture and microscopy of Leishmania (chagasi) infantum. Two hundred and nine domiciled dogs from an endemic area for visceral leishmaniasis in Bahia State, Brazil, were studied. Most dogs (87%) were seropositive for anti-L. chagasi antibodies by ELISA. Clinical signs of disease were recorded and the animals monitored during and after spleen puncture in order to detect possible complications associated with the procedure. From a total of 257 splenic punctures in the 209 animals, only three minor events occurred, with no significant consequence for the animals and no association with risk factors. Leishmania was isolated from 149/180 (83%) seropositive dogs, and from 6/26 (23%) seronegative animals. The procedure did not cause adverse side effects or unnecessary suffering and confirmed the diagnosis in a large percentage of dogs. We conclude that spleen aspiration can be considered an effective and safe procedure for the definitive diagnosis of canine visceral leishmaniosis.     

The Correlation between Age,Body Weight and Testicular Parameters in Murrah Buffalo Bulls Raised in Brazil

Buffalo are an economically important source for meat and milk production, especially in Brazil. However, important aspects of their biology remain unknown thus far. Herein, we describe the reproductive characteristics of male Murrah buffalo (Bubalus bubalis) raised under extensive management conditions by applying biometrics associated with testicular weight. We analyzed seven males, divided into two groups: G1, which consisted of four 18-month-old animals, and G2, which consisted of three 24-month-old animals. Testicular development occurs slowly in Murrah buffalo, suggesting a delay of sexual maturity. The biometric testicular parameters analyzed were scrotal circumference, testicular weight, testicular length, testicular width, testicular thickness and testicular circumference. Our data indicate strong correlations between SC, age and body weight, and additional significant relationships were identified between body weight, age and other testicular parameters. Thus, these parameters are suitable indicators when selecting bulls for breeding purposes.     

Xanthorhodopsin: a proton pump with a light-harvesting carotenoid antenna

Energy transfer from light-harvesting carotenoids to chlorophyll is common in photosynthesis, but such antenna pigments have not been observed in retinal-based ion pumps and photoreceptors. Here we describe xanthorhodopsin, a proton-pumping retinal protein/carotenoid complex in the eubacterium Salinibacter ruber. The wavelength dependence of the rate of pumping and difference absorption spectra measured under a variety of conditions indicate that this protein contains two chromophores, retinal and the carotenoid salinixanthin, in a molar ratio of about 1:1. The two chromophores interact strongly, and light energy absorbed by the carotenoid is transferred to the retinal with a quantum efficiency of approximately 40%. The antenna carotenoid extends the wavelength range of the collection of light for uphill transmembrane proton transport.     

Immunosuppression abrogates resistance of young rabbits to Rabbit Haemorrhagic Disease (RHD)

Rabbit Haemorrhagic Disease (RHD) is caused by a calicivirus (RHDV) that kills 90% of infected adult European rabbits within 3 days. Remarkably, young rabbits are resistant to RHD. We induced immunosuppression in young rabbits by treatment with methylprednisolone acetate (MPA) and challenged the animals with RHDV by intramuscular injection. All of these young rabbits died within 3 days of infection due to fulminant hepatitis, presenting a large number of RHDV-positive dead or apoptotic hepatocytes, and a significant seric increase in cytokines, features that are similar to those of naïve adult rabbits infected by RHDV. We conclude that MPA-induced immunosuppression abrogates the resistance of young rabbits to RHD, indicating that there are differences in the innate immune system between young and adult rabbits that contribute to their distinct resistance/susceptibility to RHDV infection.     

Oviposition preference assessment of Diabrotica speciosa (Coleoptera: Chrysomelidae) for different soybean genotypes

This study assessed current research methods and applied them to tests of oviposition preference by Diabrotica speciosa (Germar) for different soybean genotypes; the correlation between the number of eggs per plant and leaf intake was evaluated. The experiments were divided into four parts: (i) assessing the preferred oviposition substrate; (ii) standardizing the number of D. speciosa pairs, (iii) evaluating the preferred soybean plant age, and (iv) testing the preference for oviposition on different soybean genotypes, and evaluating its correlation with leaf intake under laboratory conditions. Females of D. speciosa preferred to lay eggs in the soil, with the highest number of eggs laid in the presence of a growing soybean plant. The genotypes PI 227687, DM 339, and PI 274454 were the least preferred varieties for oviposition, while BRSGO 8360 was the most preferred genotype. Egg counts were not correlated with leaf intake, except for the variety IGRA RA 626 RR, which showed positive correlation. Our discoveries may be helpful for second-crop use of resistant genotypes in areas where different crops are cultivated, by reducing the pest density off-season.     

The Neurospora checkpoint kinase 2: a regulatory link between the circadian and cell cycles

The clock gene period-4 (prd-4) in Neurospora was identified by a single allele displaying shortened circadian period and altered temperature compensation. Positional cloning followed by functional tests show that PRD-4 is an ortholog of mammalian checkpoint kinase 2 (Chk2). Expression of prd-4 is regulated by the circadian clock and, reciprocally, PRD-4 physically interacts with the clock component FRQ, promoting its phosphorylation. DNA-damaging agents can reset the clock in a manner that depends on time of day, and this resetting is dependent on PRD-4. Thus, prd-4, the Neurospora Chk2, identifies a molecular link that feeds back conditionally from circadian output to input and the cell cycle.     

Partial purification and characterization of pectin methylesterase from acerola (Malpighia glabra L.)

The enzyme pectin methylesterase (PME) is present in acerola fruit and was partially purified by gel filtration on Sephadex G-100. The results of gel filtration showed different PME isoforms. The total PME (precipitated by 70% salt saturation) and one of these isoforms (fraction from Sephadex G-100 elution) that showed a molecular mass of 15.5 +/- 1.0 kDa were studied. The optimum pH values of both forms were 9.0. The total and the partially purified PME showed that PME specific activity increases with temperature. The total acerola PME retained 13.5% of its specific activity after 90 min of incubation at 98 degrees C. The partially purified acerola (PME isoform) showed 125.5% of its specific activity after 90 min of incubation at 98 degrees C. The K(m) values of the total PME and the partially purified PME isoform were 0.081 and 0.12 mg/mL, respectively. The V(max) values of the total PME and the partially purified PME were 2.92 and 6.21 micromol/min/mL/mg of protein, respectively.     

Chickens treated with a nitric oxide inhibitor became more resistant to Plasmodium gallinaceum infection due to reduced anemia,thrombocytopenia and inflammation

Malaria is a serious infectious disease caused by parasites of the Plasmodium genus that affect different vertebrate hosts. Severe malaria leads to host death and involves different pathophysiological phenomena such as anemia, thrombocytopenia and inflammation. Nitric oxide (NO) is an important effector molecule in this disease, but little is known about its role in avian malaria models. Plasmodium gallinaceum- infected chickens were treated with aminoguanidine (AG), an inhibitor of inducible nitric oxide synthase, to observe the role of NO in the pathogenesis of this avian model. AG increased the survival of chickens, but also induced higher parasitemia. Treated chickens demonstrated reduced anemia and thrombocytopenia. Moreover, erythrocytes at different stages of maturation, heterophils, monocytes and thrombocytes were infected by Plasmodium gallinaceum and animals presented a generalized leucopenia. Activated leukocytes and thrombocytes with elongated double nuclei were observed in chickens with higher parasitemia; however, eosinophils were not involved in the infection. AG reduced levels of hemozoin in the spleen and liver, indicating lower inflammation. Taken together, the results suggest that AG reduced anemia, thrombocytopenia and inflammation, explaining the greater survival rate of the treated chickens.     

Effect of feeding time on dietary protein utilization and growth of juvenile Senegalese sole (Solea senegalensis)

The present study aimed to determine the effect of feeding time on growth and nitrogen excretion in juvenile sole. An 84‐day growth trial was conducted, in which food was supplied to three triplicate groups of juvenile Senegalese sole (3 g wet weight) at different schedules – diurnal, nocturnal and mixed. At the end of the growth trial, ammonia and urea excretion was assessed during a 24 h cycle. Improved growth (1.3% vs. 0.9% day^?1, specific growth rate), higher nitrogen retention (0.35 vs. 0.27 g N kg^?1 day^?1), lower ammonia excretion (209 vs. 272 mg N‐NH₄ kg^?1 day^?1) and lower total nitrogen excretion (278 vs. 352 mg N kg^?1 day^?1) were found in daytime‐fed fish compared with night‐fed fish. Fish in the mixed feeding regime showed intermediate values of ammonia and total nitrogen excretion, but did not differ from day‐fed fish regarding the other parameters. Results indicate that juvenile sole at a period of their life cycle appear to use more efficiently dietary protein for somatic growth under a diurnal than under a nocturnal feeding regime. This suggest that at least during a time‐window in the juvenile rearing a diurnal feeding regime might be more effective in the production of this species.