Do closely related species share of feeding niche along growth? Diets of three sympatric species of the mojarras (Actinopterygii: Gerreidae) in a tropical bay in southeastern Brazil

Understanding the trophic relationships among closely related species is a way to obtain subsidies for their management and conservation of their habitats. The diets of three co-occurring abundant fish species of the Gerreidae family (Diapterus rhombeus, Eucinostomus argenteus and Eucinostomus gula) in a tropical bay were described. The tested hypothesis was that the three sympatric species present shifts in their use of resource during the ontogenetic development to facilitate their coexistence. Size groups for each species were categorized according to breakpoints in the morphological structures determined by piecewise regression models. Significant overlapping in diets was found for all size classes of D. rhombeus but not for size classes of the Eucinostomus genus. Furthermore, different size classes of D. rhombeus did not overlap diet with size classes of the Eucinostomus genus. The specialization in feeding niches corresponding to growth seems to bring benefits for this group of fish rather than a generalist feeding strategy. The hypothesis of the available resources partitioning was accepted only between the two genera (Diapterus and Eucinostomus), and among size classes of the Eucinostomus genus that seemed to follow the principle of limiting similarity. However, different size classes of D. rhombeus exhibited strong evidence of an intraspecific overlapping of the trophic niche. It seems that different processes related to use of the trophic niche dimension are structuring these closely related fish species.     

Differentially expressed proteins associated with drought tolerance in bananas (<Emphasis Type="Italic">Musa</Emphasis> spp.)

Bananas are one of the most important fruits in tropical and subtropical regions worldwide. Each year, banana plantations expand, but the areas available are mostly dry lands. The establishment of strategies for obtaining drought tolerant cultivars depends on understanding of biological responses at genetic, molecular and biochemical levels. Proteomics is a powerful tool for functional characterization of the response of plants to abiotic stress and little is known about drought tolerance in Musa spp. Therefore, the aim of this study was to identify proteins related to drought tolerance in two contrasting banana genotypes, Prata Anã and BRS Tropical, susceptible and tolerant to drought, respectively. Proteins were extracted from rhizomes of bananas grown under greenhouse conditions with control, irrigated and water deficit regimes. The differential protein expression pattern was established by two-dimensional (2-D) electrophoresis and spots analyzed in nano Q-Tof Micro UPLC. Twenty-three differentially expressed proteins were found in the tolerant genotype (BRS Tropical) under water deficit, with proteins involved in metabolism, defense and transport. Proteins were classified according to known function and biosynthetic pathways. Signaling proteins in response to water stress, especially for the biological function of growth and development of plants cells, were also encountered, whereas heat shock proteins played a significant role. This is the first report of proteomic analysis for drought tolerance in ‘Pome’ and ‘Silk-type’ bananas containing the ‘B’ genome. Our work provides insights into Musa spp. response to drought and data for further studies regarding molecular mechanisms, which determine how Musa spp. cells better overcome environmental perturbations.     

Molecular Identification of Candida Species in the Oral Microbiota of Individuals with Down Syndrome: A Case–Control Study

Mycopathologia - Candida species are common in the human oral microbiota and may cause oral candidiasis (OC) when the microbiota equilibrium is disturbed. Immunosuppressed individuals are...     

Microbiological quality of water and dialysate in a haemodialysis unit in Ponta Grossa-PR, Brazil

AIMS: The objective of the study was to determine the microbiological quality of samples of water and dialysate in a haemodialysis unit. METHODS AND RESULTS: Seventy-two samples each of water and dialysate were collected during November 2003 to April 2004. The following microbiological analyses were performed: test for total and faecal coliforms, which produced negative results for all the samples; counts of total heterotrophic bacteria, where three samples of water and two of dialysate showed levels higher than those permitted by national standards; and endotoxin assay, which revealed high quantities only in samples of water that preceded reverse osmosis. Nonfermenting Gram-negative bacteria were identified in 54 samples of dialysate and in 26 samples of water. The test for adhesion to an inert surface showed that various bacteria were capable of forming biofilms. Twenty-seven per cent of the bacteria were resistant to sodium hypochlorite at 500 ppm for 10-min contact time. Sixty per cent of the isolates were resistant to three or more antibiotics. CONCLUSIONS: Water and dialysate can be a source of infection for patients who need haemodialysis. SIGNIFICANCE AND IMPACT OF THE STUDY: An adequate system for water treatment, disinfection of the haemodialysis system and microbiological monitoring of the water and dialysate are necessary to reduce bacteraemia and pyrogenia outbreaks.     

In vitro organogenesis of Citrus volkameriana and Citrus aurantium

In vitro organogenesis of Citrus volkameriana and C. aurantium was studied considering three explant types: epicotyl segment, internodal segment, and hypocotyl segment with attached cotyledon fragment. The explants were cultured in medium according to Grosser and Gmitter (EME) supplemented with 0, 0.5, 1.0, 1.5, and 2.0 mg dm^{− 3} 6-benzyl-aminopurine (BAP), incubated firstly in darkness for 4 weeks, and then transferred to 16-h photoperiod for 2 weeks. Comparing epicotyl and internodal segments, a higher percentage of responsive explants and a higher number of shoots per explant were obtained with epicotyl segments, regardless of the BAP concentration. For C. volkameriana the highest percentage of responsive epicotyl segments (42 %) was obtained in EME with 1.0 mg dm⁻³ BAP, while for C. aurantium (59 %) in EME with 0.5 mg dm⁻³ BAP. The organogenesis efficiency was the best with the use of the hypocotyl segment with attached cotyledon fragment (77 % for C. volkameriana and to 75 % for C. aurantium). With this explant the morphogenesis occurred only in the hypocotyl region. The in vitro organogenesis was characterized by histological analyses showing that the morphogenic process started in the cambium region near the explant cut end.     

Technical viability of the production,partial purification and characterisation of inulinase using pretreated agroindustrial residues

The present work aimed to study the viability of the use of sugarcane molasses and corn steep liquor (CSL) in a sequential inulinase production performing an up-stream pretreatment of these agroindustrial residues. A sequential strategy was used applying three central composite rotatable designs (CCRDs) to optimise medium composition, followed by a down-stream step. The medium containing 150 g L⁻¹ molasses, 50 g L⁻¹ CSL and 6 g L⁻¹ yeast extract, yielded a maximum inulinase production of 1,294 ± 7 U mL⁻¹, after 72 h of fermentation. A down-stream evaluation was carried out using an expanded bed of Streamline DAE resin (Pharmacia), with and without the up-stream treatment. The results showed that the enzyme could not be recovered from the non-pretreated medium, whereas a yield of 91% was obtained in the adsorption stage from the medium prepared with the up-stream treatment, showing the viability of producing the enzyme inulinase from agroindustrial residues using the integrated process.     

Mating behavior of the coffee leaf-miner Leucoptera coffeella (Guérin-Mèneville) (Lepidoptera: Lyonetiidae)

Despite the importance of Leucoptera coffeella (Guérin-Mèneville) in coffee production worldwide, there is a lack of information on its reproductive biology. This knowledge will help in mass rearing, as well as support the development of behavioral control techniques for this insect. The purpose of the study was to determine the periodicity of mating and male capture and describe the mating behavior L. coffeella. In laboratory, we observed the periodicity of mating with virgin couples of different ages, zero to five days after emergence. Male activity was studied in a 0.7 ha coffee plantation, cv. Catuaí, where Delta traps were installed at 0.5 m above ground, using either virgin females or rubber septa lured with the synthetic sex pheromone. The sequence of mating behavior was studied by making visual observations and recorded of pairs placed on individual plastic tubes. Mating occurred between 4h and 6h of photophase, when the highest frequencies involved pairs with ages of one and three days after emergence, with peak of mating occurring in 5th hour of photophase. The young or old pairs showed significantly copulation frequency and the peak of matings advance in 1h. The highest male capture occurred at 12p.m. and 13 p.m. by traps with virgin females or traps with synthetic sex pheromone lures, respectively. L. coffeella is one insect with diurnal mating and the mating behavior was not different from what is know for other Lepidoptera species.     

Significance of AgNOR measurement in thyroid lesions

OBJECTIVE: To evaluate the discriminating potential of AgNOR area measurement and count in thyroid tumors using static cytometry equipment. STUDY DESIGN: Slides were analyzed by a computerized system for image analysis, CAS 200 (Becton & Dickinson, U.S.A.), using the Cell Measurement computer program (CAS 200, Becton & Dickinson). The argyrophilic reaction (NORs) was evaluated with a 400-fold amplification directly from the computer monitor. RESULTS: Thirty-three cases were analyzed for AgNOR staining. The cases studied included 3 goiters, 10 follicular adenomas, 6 Hürthle adenomas, 4 follicular carcinomas, 7 papillary carcinomas, and 3 Hürthle carcinomas. A total of 6,600 nuclei were evaluated. For statistical purposes, lesions were classified as benign and malignant, and both the number and the area of counted NORs showed very similar values. The NORs median among 19 benign tumors was 1.484 (SD +/- 0.265) and of 14 malignant tumors was 1.436 (SD +/- 0.414); the NORs areas were 2.6584 (SD +/- 1.0653) and 2.3643 (SD +/- 0.6320), respectively. CONCLUSION: Our results showed that AgNOR evaluation was not a significant parameter to discriminate between malignant and benign thyroid lesions.