Antibacterial activity of Venda medicinal plants

Crude methanol and water extracts of 36 plants, employed in the treatment of diseases of probable bacterial etiology by the Venda people, were screened for antibacterial activity. Combretum molle, Peltophorum africanum, Piper capense, Terminalia sericea and Zanthoxylum davyi were the most active and presented MIC values < or =1.00 mg/ml.     

Using density management diagrams to assess crown fire potential in Pinus pinaster Ait. stands

Context

Density management diagrams (DMDs) are useful for designing, displaying and evaluating alternative density management regimes for a given stand-level management objective. The inclusion of variables related to crown fire potential within DMDs has not previously been considered.

Aims

The aim of this study was to include isolines of variables related to crown fire initiation and spread in DMDs to enable identification of stand structures associated with different types of wildfire.

Methods

Biometric and fuel data from maritime pine (Pinus pinaster Ait.) stands in NW Spain were used to construct DMDs. Different surface and crown fire behaviour models were used together to estimate crown fire potential.

Results

The crown fire potential varied greatly throughout development of the maritime pine stands. Low stands were more prone to crowning. The type of crown fire was mainly determined by stand density.

Conclusion

The DMDs developed can be used to identify relationships between stand structure and crown fire potential, thus enabling the design of thinning schedules aimed at reducing the likelihood of crowning.     

Comparative performance of the red flour beetle Tribolium castaneum (Coleoptera: Tenebrionidae) on different plant diets

Tribolium castaneum is a pest of stored foods that causes serious economic losses. Understanding insect nutritional requirements and the effects of different diets on insect development can provide tools for developing strategies to control insect and integrated pest management systems. In this work we studied the performance of the T. castaneum on different plant diets composed of Vigna unguiculata, Phaseolus vulgaris and wheat flours. The diets interfered differentially with development and insect survival. Larvae size was reduced about 60 % in larvae fed with V. unguiculata flour. A delay in pupae formation was also observed. The larval mortality of 100 % was observed in the P. vulgaris diet. Carbohydrate and triglyceride showed variations during development and with different diets. Larvae fed with wheat diets showed a high concentration of carbohydrates 21 days after hatching (DAH) and triglyceride at 15 and 21 DAH. Larvae fed with wheat diets showed α-amylase activity during development. At 15 DAH the activity of larvae fed with V. unguiculata increased about 50 %. Cysteine protease activity in larvae fed with wheat remained high throughout development. Serine protease activity also varied according to diets. These results show that the nutritional state of developing larvae varies greatly with respect to triglycerides, carbohydrate and digestive enzymes depending on the diet and larval stage. Altogether, these results show that changes in dietary nutrients can interfere with insect physiology. Therefore changes in diet composition that may deprive insects of essential nutrients or include toxic compounds might be a good control strategy for stored product pests.     

Habitat split and the global decline of amphibians

The worldwide decline in amphibians has been attributed to several causes, especially habitat loss and disease. We identified a further factor, namely "habitat split"-defined as human-induced disconnection between habitats used by different life history stages of a species-which forces forest-associated amphibians with aquatic larvae to make risky breeding migrations between suitable aquatic and terrestrial habitats. In the Brazilian Atlantic Forest, we found that habitat split negatively affects the richness of species with aquatic larvae but not the richness of species with terrestrial development (the latter can complete their life cycle inside forest remnants). This mechanism helps to explain why species with aquatic larvae have the highest incidence of population decline. These findings reinforce the need for the conservation and restoration of riparian vegetation.     

Assessment of qualitative and quantitative parameters of healthy thyroid gland in adult horses by magnetic resonance imaging

In humans and pets, magnetic resonance imaging (MRI) provides important adjunctive anatomic information about the thyroid and its adjacent structures. To the best of our knowledge, however, no studies have been reported regarding the use of MRI for thyroid evaluation in horses. The aim of this study was to obtain qualitative and quantitative parameters of healthy thyroid gland in adult horses by MRI. Eleven horses were submitted to thyroid MRI evaluation. The healthy thyroid of these animals was ensured by normal examinations performed before (free thyroxine and ultrasound) and after (cytology) to MRI. It was concluded that the dorsal spin-echo T1-weighted, fast spin-echo T2-weighted, sagittal STIR and a three-dimensional T1-weighted gradient echo were the sequences that best characterized the thyroid lobes. Qualitatively, there was a significant variation in the elliptical format of some lobes considering the sagittal plane, which oscillated between rounded and flattened conformation. Excellent reproducibility of the quantitative thyroid parameters obtained was verified. The thyroid gland total volume mean of observers was 14.31 cm³ (±0.69). In relation with comparisons between quantitative parameters of left and right lobes, only differences regarding their respective lengths were observed. Thus, we can infer that the difference in some thyroid lobes format can be explained by the significant variation identified between left and right lobes lengths.     

Buriti pulp oil did not improve high-fat diet-induced metabolic disorders in c57bl/6 mice

Metabolic syndrome (MetS) and obesity are growing in many parts of the world, becoming public health problems. It is proposed that foods with functional properties can assist in the treatment of these diseases. Crude buriti pulp oil (BPO) is a food traditionally consumed by residents in the Pantanal, Cerrado and Brazilian Amazon. It is rich in oleic acid, tocopherols and carotenoids, emerging as a potential functional food. Thus, this study aimed to evaluate the effect of the supplementation of BPO on metabolic disorders caused by a high-fat diet. Four groups of C57BL6 mice were used, a lean group with AIN-93M diet and control oil supplementation, an obese group with a high-fat diet and control oil supplementation, and two obese groups with a high-fat diet and BPO supplementation in the amounts of 50 and 100 mg/kg. BPO worsened the metabolic state caused by the high-fat diet, worsening risk factors associated with MetS, as the abdominal circumference and retroperitoneal fat, serum levels of total cholesterol, uric acid, alanine transaminase, glucose and triglycerides, and renal fat, in addition to changes in glycaemic control and oxidative stress markers. C57BL/6 mice fed with a high-fat diet and supplemented with BPO presented a worsening in metabolic risk factors associated with MetS.     

Influence of different warming temperatures on the vitrified testicular fragments from pre-pubertal cat

Testicular vitrification is an alternative to preserve the genetic material of pre-pubertal animals. However, there are few studies on post-vitrification warming. Hence, the aim was to compare the influence of different warming temperatures on vitrified testicular fragments from pre-pubertal cats. The testicles were fragmented and divided into a control group (non-vitrified) and vitrified, using an association between dimethylsulphoxide and glycerol. The vitrified fragments were warmed at 50, 55 and 60°C/5 s. Morphological and morphometric evaluations were carried out using classical histology. Afterwards, the mitochondrial activity was evaluated using Rhodamine 123. The data were expressed in mean and standard error. The differences were considered significant when p < .05. In the histomorphological analysis, the testicular fragment presented seminiferous tubules with poorly developed germinal epithelium, compatible with pre-pubertal animals. The group warmed at 50°C presented similar to the control regarding the maintenance of the integrity of the tubules and cells, without stromal rupture and lamina propria alteration, as well as regarding the maintenance of the junctions between the cells. The group warmed at 55°C showed reduction of the cell junctions, and the one warmed at 60°C had increased detachment of the basement membrane (p < .05). The warming caused a reduction in the tubular diameter inversely proportional and progressive to the increase in temperature, with the highest diameter in the control group and the lowest in the 60°C group. The control group showed a lower incidence of Rhodamine 123, followed in ascending order of the warmings at 55 and 60°C. The higher mitochondrial activity was obtained with 50°C, showing an increase of the metabolic cell function at this temperature. It was concluded that the testicular fragment of pre-pubertal cats presents a better preserved morphology, morphometry and viability when warmed at 50°C.     

Exposure to metallic mercury in workers in a tropical chloralkali plant evaluated through urine analysis,Rio de Janeiro,Brazil.

Occupational exposure to Hg vapour was investigated in 78 workers during three periods with different temperatures: August 1991, December 1991, and February 1992. Each individual was sampled twice in each period; before and after a six working days period (with a two free days interval). As an attempt to normalise Hg excretion urine was sampled always after a normal 8 hours night sleeping and immediately frozen. Mineralisation was done with acid and oxidant mixture and determination by cold vapour Atomic Absorption Spectrophotometry (Varian VGA-76 and AA-1475). Analytical accuracy was controlled by routine analysis of certified reference material (Seronorm TM trace elements, Nycome As diagnostics Olso - Norway) and all samples were analysed in triplicates. Of a total of 355 samples analysed 13% were over the maximum limit for occupational exposure (50 µg.l-1 or ppb). From the 78 individuals investigated 13% presented average value smaller than 10 ppb; just 8% had the average over 50 ppb; 64% showed averages smaller than 30 ppb; and 28% were between 30 and 50 ppb. Seasonal variation was observed with the highest values in the hottest periods. High variability was observed in the same individual even within an interval of just few days (seven days). No increase of Hg in urine after the six days of exposure was observed when compared with the values after the two free days interval.     

Participatory maize breeding for low nitrogen tolerance

The local maize variety Sol da Manhã has a broad genetic background. It was identified in 1985 in a participatory evaluation trial as being suitable for cultivation under low soil fertility conditions in Sol da Manhã, situated in Seropédica, State of Rio de Janeiro, Brazil. The variety was then improved for 6 selection cycles by the formal breeding sector at the experimental station of Embrapa Agrobiologia. There were three cycles of mass selection, one selection cycle between and within half-sib families, one selection cycle within full-sib families, and one selection cycle between and within S₁ families. Thereafter, the variety was improved in collaboration with the informal sector, viz. a group of farmers of the agricultural community of Sol da Manhã for 6 cycles of mass selection. The variety was evaluated in 1994 in field trials for grain yield and nitrogen use efficiency. Sol da Manhã can be characterised as efficient in nitrogen use, under both favourable and unfavourable growing conditions.