Testicular shape,scrotal skin thickness and testicular artery blood flow changes in bulls of different ages

The aim of this study was to compare the biometric testicular characteristics, skin thickness and haemodynamics of the testicular artery of 12- and 24-month-old bulls using Doppler ultrasonography, the study was conducted using 48 indicus-taurus animals. The scrotal circumference (SC) and biometry characteristics of the bulls were measured to calculate the testicular volume. Doppler ultrasonography was used to obtain the haemodynamic values of the testicular artery. The skin thickness and volume were lower (p<.01) in the younger bulls (12 months:4.68 ± 0.68 mm; 168.76 ± 47.96 cm³) versus 24 months (5.05 ± 0.89; 499.73 ± 129.24 cm³) animals (p<.01). During diastole, mean velocity was lower in the 12 months (7.98 ± 3.83) than in the 24 months (11.37 ± 4.15) animals (p <.05). The 12-month-old animals had higher pulsatility and resistivity indices (0.49 ± 0.02; 0.51 ± 0.20) compared to the 24-month-old animals (0.32 ± 0.16; 0.40 ± 0.15) (p < .05). The final testicular end velocity was lower in animals with long/moderate-shaped (L/M) (7.31 ± 2.91) than in those moderate/oval-shaped (M/O) (11.48 ± 3.88) testicles (p < .05). Animals with L/M testes presented higher pulsatility values and resistivity indices (0.51 ± 0.05; 0.55 ± 0.04) compared to animals with M/O shape (0.29 ± 0.20; 0.36 ± 0.15). We showed that the blood flow of the supra testicular artery between the two evaluated ages differed, and that 24-month-old bulls presented better thermoregulation capacity. Animals with a long/moderate testicular format presented a greater vascular resistance, which was imposed on the blood flow due to the anatomical differences in the testicular artery, resulting in lower velocity, and indicating better heat dissipation in this format.     

A comparative study of methods for diagnosis of obesity in an urban mixed-race population in Minas Gerais, Brazil

BACKGROUND: Obesity is defined as an excess of total body fat and may be assessed by different methods. The objective of the present study was to establish the discriminatory power of anthropometric data in determining obesity. METHODS: The subjects comprised 685 individuals, aged 20-79 years, sampled from a population-based survey. The following indicators were used: body mass index (BMI), waist circumference (WC) and total body fat percentage estimated with both Siri's equation (%BF Siri) and foot-to-foot bioelectrical impedance analysis (%BF BIA). Sensitivity and specificity of different cut-off points for each method were determined using %BF BIA as reference. RESULTS: Of 685 participants, 57.6% were aged >/= 40 years, 69.9% were women and 72.6% self-referred themselves as non-white. To classify obesity based on sex and age among women aged 0.05). Classifying according to skin colour did not change cut-off points in any indicator. CONCLUSION: BMI and WC better discriminate obesity among women and men aged >/= 40 years from a mixed-race population.     

Magnetic Field and Plasma Observations at Mars: Initial Results of the Mars Global Surveyor Mission

The magnetometer and electron reflectometer investigation (MAG/ER) on the Mars Global Surveyor spacecraft has obtained magnetic field and plasma observations throughout the near-Mars environment, from beyond the influence of Mars to just above the surface (at an altitude of approximately 100 kilometers). The solar wind interaction with Mars is in many ways similar to that at Venus and at an active comet, that is, primarily an ionospheric-atmospheric interaction. No significant planetary magnetic field of global scale has been detected to date (<2 x 10(21) Gauss-cubic centimeter), but here the discovery of multiple magnetic anomalies of small spatial scale in the crust of Mars is reported.     

Effects of concanavalin A on the progesterone production by bovine steroidogenic luteal cells in vitro

The aim of this study was to evaluate the effects of concanavalin A (CONA) on the progesterone (P4) production by bovine steroidogenic luteal cells (LCs) in vitro. Luteal cells were collected during the mid‐luteal stage (at 10–12 days following ovulation) and processed in the laboratory. Luteal cells were grown for 7 days in a humid atmosphere with 5% CO₂, with or without 10% foetal bovine serum, and were subjected to the following treatments: control: no treatment; CONA (10 μg/ml); LH (100 μg/ml); CONA + LH; LH (100 μg/ml) + prostaglandin F2α (PGF2α) (10 ng/ml); CONA + LH + PGF2α. Samples of the culture media were collected on days 1 (D1) and 7 (D7) for P4 quantification. The cells were counted on D7 of culture. Differences between treatments were considered statistically significant at p < .05. Culture in the presence of CONA decreased the P4‐secreting capacity of LCs on D7 of culture, particularly in the absence of serum. The cell numbers did not change between treatments.     

Lythrum hyssopifolia (lesser loosestrife) poisoning of sheep in Victoria

Objective To document an ovine disease attributed to the consumption of Lythrum hyssopifolia (lesser loosestrife). Procedures Historical and histological review of field and experimental cases. Results 1–20% mortality occurred in sheep flocks grazing paddocks where L. hyssopifolia was the predominant green vegetation. Well‐documented disease outbreaks occurred in summer on nine farms across Victoria between 1974 and 2002. Liver damage occurred in all nine outbreaks, with kidney damage in at least eight. Hepatocyte necrosis was usually zonal to midzonal (zone 2) in the liver samples from four farms and periacinar (zone 3) in those from three farms, but some livers showed only single‐cell necrosis. Multinucleate hepatocytes near necrotic areas were a feature in six cases. Proximal tubular epithelium appeared to be the primary renal target and brown granules were often present in renal tubules. Biochemical and histological evidence of liver and kidney damage was obtained from two sheep experimentally pen‐fed harvested L. hyssopifolia. Conclusion Chemicals in L. hyssopifolia are toxic to ovine hepatocytes and renal tubular epithelial cells.     

Changes in distance decay relationships after river regulation: similarity among fish assemblages in a large Amazonian river

The construction of large dams has changed natural hydrology of many rivers in South America. Considering that little is known about the reorganisation of nonmigratory fish assemblages following an impoundment, we investigated changes caused by the construction of Lajeado Dam on the spatial distribution of nonmigratory fish along the Tocantins River, a large Amazonian river. In particular, we investigated changes in distance decay of community similarity (initial similarity and halving distance) in periods that preceded and followed the construction of the dam. For this study, we analysed data collected over a four‐year period, including seven sites distributed along the Tocantins River (~270 km). Initial similarity showed high values and little variation over the years. Halving distance, on the other hand, changed considerably after impoundment, showing progressive smaller values. In the first 2 years after impoundment, halving distance decreased by more than half of the initial value, indicating changes in distance decay relationships. An ordination analysis nonmetric multidimensional scaling (NMDS) indicated substantial changes in assemblage structure between pre‐ and postimpoundment periods, especially in sites close to the dam. In addition, after river regulation, we recorded shifts in species abundance across sites, while numerical dominance increased and local richness decreased in sites near the dam. Our results indicate that the dam changed diversity gradients along the river corridor, increasing the distance decay of assemblage similarity. All these findings evidence that nonmigratory fish assemblages are particularly vulnerable to river regulation.     

Dual inoculation of a woody legume (Centrolobium tomentosum) with rhizobia and mycorrhizal fungi in south-eastern Brazil

The integration of N₂ fixing trees into stable agroforestry systems in the tropics is being tested due to their ability to produce high biomass N and P yields, when symbiotically associated with rhizobia and mycorrhizal fungi. The growth of Centrolobium tomentosum Guill. ex Benth, a native leguminous tree from the Brazilian Atlantic Forest, was assessed with dual inoculation of Rhizobium spp and mycorrhizal fungi under field conditions. Complete fertilization was compared to treatments of inoculation with selected rhizobia strains BHICB-Ab1 or BHICB-Ab3, associated or not to arbuscular mycorrhizal (AM) fungi. The dual inoculation increased the height and growth in relation to the plants treated with rhizobia alone. Plants inoculated with strain BHICB-Ab1 and arbuscular mycorrhizal fungi (AMF) exhibited an increase of 56% dry matter over uninoculated control and nitrogen accumulation was greater than with BHICB-Ab3 inoculated plants. Strain BHICB-Ab1 presented a synergetic relationship with mycorrhizal fungi since the combined inoculation with BHICB-Ab1 enhanced plant height and dry weight more than single inoculation while the growth of BHICB-Ab3 plants was not modified by AMF inoculation. Arbuscular mycorrhizal fungi enhanced plants survival and seemed to favour the nodule occupation by rhizobia strains as compared to the non-mycorrhizal plants. Inoculation with selected rhizobia and AMF improved the growth of C. tomentosum under field conditions. This revised version was published online in June 2006 with corrections to the Cover Date.     

Origins and diversity of the Portuguese Landrace of Eucalyptus globulus

The Portuguese Landrace of Eucalyptus globulus is of unknown origin, with the earliest plantings of this tree species dating back to the early 19th century. In Portugal it is currently a major seed source for plantations and is also used in breeding programs. Eucalyptus globulus is native to south-eastern Australia. The substantial genetic differentiation of chloroplast and nuclear DNA markers between different native geographic races of this species allowed us to uncover the Australian origins of the Portuguese Landrace and to study its genetic diversity. To achieve this, we sequenced a highly polymorphic region of chloroplast DNA from 47 Portuguese Landrace individuals, and genotyped 34 of these using seven nuclear microsatellites. We compared these individuals to those in a database comprising chloroplast DNA sequence profiles from 292 native trees and seven nuclear microsatellites from 372 native trees. The majority of the Portuguese Landrace samples had closest affinities, in both marker systems, to native trees from south-eastern Tasmania, but some had affinities to trees from south-eastern Victoria. The discrepancies in the affinities indicated by chloroplast versus nuclear DNA markers could be explained by inter-race hybridisation after introduction. The genetic diversity in the Portuguese Landrace was less than that found in native E. globulus at the species level, but was similar to the average diversity found in native races of the species. This study demonstrates the power of using independent marker systems to identify the origins and diversity of domesticated populations, by comparison with variation in native stands.     

The prion-like protein Doppel enhances ovine spermatozoa fertilizing ability

The function of prion‐like protein Doppel was suggested to be related to male fertility. In this study, the importance of ovine Doppel polypeptide on spermatozoa capacitation and fertilization was evaluated. After refolding, recombinant Doppel (rDpl) was supplemented with different concentrations (40, 80 or 190 ng/ml) to ovine spermatozoa during the capacitation process. In experiment 1, post‐thawed ovine spermatozoa were incubated with different concentrations of rDpl during 1 h for swim‐up, and changes in sperm motility, concentration, vigour, viability and capacitation were monitored (10 replicates). In experiment 2, the fertilization ability of post‐swim‐up spermatozoa incubated as above was tested through heterologous fertilization of bovine in vitro matured oocytes (n = 423, three replicates). Regardless of dosage, rDpl improved (p ≤ 0.03) spermatozoa viability. Sperm individual motility and vigour were the highest (p ≤ 0.04) for the group receiving 190 ng/ml rDpl. Sperm supplemented with the highest doses of rDpl achieved higher (p = 0.02) fertilization rates (56.0 ± 3.0%) than control (39.1 ± 2.2%) and 40 ng/ml rDpl (39.8 ± 2.7%). Preliminary data suggest that Doppel protein may enhance in vitro spermatozoa fertilizing ability.