Evaluation of Three Formulations of Culture Media for Isolation of Brucella spp. regarding Their Ability to Inhibit the Growth of Contaminating Organisms

Three culture media (Brucella agar, Farrell medium, and CITA) were compared for their effectiveness in inhibiting contamination and for isolating Brucella spp. One hundred lymph nodes from pigs (n = 50) and wild boars (n = 50) with lymphadenitis were collected in slaughterhouses in the State of Sao Paulo and were assessed on these three selective media for Brucella spp. All of the samples were negative for Brucella spp. on the three culture media. On the agar medium, fungal (70 plates) and Gram-positive bacterial (59 plates) contaminants were observed; in the CITA medium, the absence of fungal and Gram-positive bacteria on 15 plates was observed; no bacterial or fungal growth was observed on the Farrell media. The results demonstrated that the CITA and Farrell media inhibited the growth of contaminants better than the Brucella agar.

Toxicity on aquatic organisms exposed to secondary effluent disinfected with chlorine, peracetic acid, ozone and UV radiation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Minimal levels of ultraviolet light enhance the toxicity of TiO2 nanoparticles to two representative organisms of aquatic systems

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

High efficacy in hyperthermia-associated with polyphosphate magnetic nanoparticles for oral cancer treatment

Nanotherapy applied to cancer treatment is constantly evolving, and new approaches to current techniques, such as magnetohyperthermia, are being implemented to solve and minimize the limitations of conventional therapeutic strategies. The purpose of this study was to investigate the action of polyphosphate-coated maghemite nanoparticles (MNPs) on oral squamous cell carcinoma. Human oral cancer cells (UM-SCC14A) were incubated with MNPs at various concentrations and subjected to cell proliferation tests (MTT), apoptosis assays and transmission electron image analysis. Viability and apoptotic events were time and dose dependent. These in vitro tests showed that at the intermediate concentration tested there is no significant toxicity, as confirmed by transmission electron microscopy. For this reason this MNPs concentration was chosen for the subsequent in vivo tests. Oral tumor induction was performed by applying the carcinogen DMBA to Syrian hamsters. Animals were then treated by magnetohyperthermia using MNPs. No signs of general clinical symptoms of toxicity or abnormal behavioral reactions were observed. However, animals treated with MNPs and exposed to the alternating magnetic field in the hyperthermia procedure exhibited a significant and time dependent cancer regression, as confirmed by histopathological analyses and immunohistochemistry. Actually, in quantitative terms of the magnetotherapy efficacy involving these polyphosphate-coated MNPs, 100% recovery (12/12) was observed in the oral cancer tumor bearing Syrian hamsters seven days after the treatment with the magnetohyperthermia procedure. Data supports the suggestion that the MNPs-mediated hyperthermia represents a promising strategy for the treatment of oral cancer.

Ecological strategies of Al-accumulating and non-accumulating functional groups from the cerrado sensu stricto

Coordenação de Aperfei çoamento de Pessoal de Nível Superior (CAPES)

Imazapyr herbicide efficacy on floating macrophyte control and ecotoxicology for non-target organisms

the aims of this study were to determine imazapyr efficacy for floating macrophyte control and ecotoxicology for non-target organisms. For the floating macrophyte control efficacy tests were used the doses of 0,5; 1,0; 2,0; 2,5; 3,0; 3,5 and 4,0 L ha(-1) and a control with 10 replicates. The acute toxicology for non-target organisms was estimated by lethal concentration 50% (LC50 and EC50). The floating macrophyte control efficacy was over 90%. Imazapyr was classified as moderately toxic for the following biomarkers: L. minor, H. eques, B. rerio, P. caudimaculatus, P. canaliculata, and P. mesopotamicus and lightly toxic for A. caroliniana. Thus, imazapyr herbicide is a tool with great potential to be used on floating macrophyte control (E. crassipes, P. stratiotes e S. molesta) in Brazil and this practice can be evaluated by the use of application biomarkers.

Removal of clay by stingless bees: load size and moisture selection

Some organisms disperse energy, associated with the transportation of resource, which is not necessarily food. Stingless bees of Central Amazonia (Melipona flavolineata and M. lateralis) collect clay in banks along streams for nest building. The moisture of the clay varies along the bank, and bees collect clay from specific location, indicating that there is some sort of preference regarding their selection. This study aims at identifying: if larger bees carry more clay; if there is a preference for moisture of substrates; and if bees are less efficient accumulating and transporting clay when it is wet. In order to do so, I measured the size of the bees and of the pellets of clay found in the corbicula. I set up a field experiment to test substrate preferences. The amount of clay transported, increased exponentially in accordance to the size of the bee, and the preferred substrate was the driest clay. The amount and the efficiency of removal of clay were not affected by the moisture of the substrate. Despite the wet clay being denser, it does not reduce the efficiency of exploitation of the resource, but suggests that bees spend more energy to carry the same quantity of wet clay, which may be the underlying mechanism explaining their preference for removing drier clay.

Production and characterization of poly-(3-hydroxybutyrate) from recombinant Escherichia coli grown on cheap renewable carbon substrates

Although the biopolymer poly-(3-hydroxybutyrate), P[3HB], presents physicochemical properties that make it an alternative material to conventional plastics, its biotechnological production is quite expensive. As carbon substrates contribute greatly to P[3HB] production cost, the utilization of a cheaper carbon substrate and less demanding micro-organisms should decrease its cost. In the present study a 23 factorial experimental design was applied, aiming to evaluate the effects of using hydrolysed corn starch (HCS) and soybean oil (SBO) as carbon substrates, and cheese whey (CW) supplementation in the mineral medium (MM) on the responses, cell dried weigh (DCW), percentage P[3HB] and mass P[3HB] by recombinant Escherichia coli strains JM101 and DH10B, containing the P[3HB] synthase genes from Cupriavidus necator (ex-Ralstonia eutropha). The analysis of effects indicated that the substrates and the supplement and their interactions had positive effect on CDW. Statistically generated equations showed that, at the highest concentrations of HCS, SO and CW, theoretically it should be possible to produce about 2 g L(1) DCW, accumulating 50% P[3HB], in both strains. To complement this study, the strain that presented the best results was cultivated in MM added to HCS, SBO and CW ( in best composition observed) and complex medium (CM) to compare the obtained P[3HB] in terms of physicochemical parameters. The obtained results showed that the P[3HB] production in MM (1.29 g L(-1)) was approximately 20% lower than in CM (1.63 g L(-1)); however, this difference can be compensated by the lower cost of the MM achieved by the use of cheap renewable carbon sources. Moreover, using differential scanning calorimetry and thermogravimetry analyses, it was observed that the polymer produced in MM was the one which presented physicochemical properties (Tg and Tf) that were more similar to those found in the literature for P[3HB].

Lethal effects of abamectin on the aquatic organisms Daphnia similis, Chironomus xanthus and Danio rerio

Abamectin is used as an acaricide and insecticide for fruits, vegetables and ornamental plants, as well as a parasiticide for animals. One of the major problems of applying pesticides to crops is the likelihood of contaminating aquatic ecosystems by drift or runoff. Therefore, toxicity tests in the laboratory are important tools to predict the effects of chemical substances in aquatic ecosystems. The aim of this study was to assess the potential hazards of abamectin to the freshwater biota and consequently the possible losses of ecological services in contaminated water bodies. For this purpose, we identified the toxicity of abamectin on daphnids, insects and fish. Abamectin was highly toxic, with an EC50 48 h for Daphnia similis of 5.1 ng L-1, LC50 96 h for Chironomus xanthus of 2.67 mu g L-1 and LC50 48 h for Danio rerio of 33 mu g L-1. (C) 2011 Elsevier Ltd. All rights reserved.

Evaluation of the Sensitivity of Freshwater Organisms Used in Toxicity Tests of Wastewater from Explosives Company

Explosives industries are a source of toxic discharge. The aim of this study was to compare organisms sensitivity (Daphnia similis, Danio rerio, Escherichia coli and Pseudomonas putida) in detecting acute toxicity in wastewater from two explosives, 2,4,6-TNT (TNT) and nitrocellulose. The samples were collected from an explosives company in the Paraiba Valley, So Paulo, Brazil. The effluents from TNT and nitrocellulose production were very toxic for tested organisms. Statistical tests indicated that D. similis and D. rerio were the most sensitive organisms for toxicity detection in effluents from 2,4,6-TNT and nitrocellulose production. The P. putida bacteria was the organism considered the least sensitive in indicating toxicity in effluents from nitrocellulose.

Evolution of time-control mechanisms in subterranean organisms: cave fishes under light-dark cycles (Teleostei: Siluriformes, Characiformes)

Subterranean organisms are excellent models for chronobiological studies, yet relatively few taxa have been investigated with this focus. Former results were interpreted as a pattern of regression of circadian locomotor activity rhythms in troglobitic (exclusively subterranean) species. In this paper we report results of experiments with cave fishes showing variable degrees of troglomorphism (reduction of eyes, melanic pigmentation and other specializations related to the hypogean life) submitted to light-dark cycles, preceded and followed by several days in constant darkness. Samples from seven species have been monitored in our laboratory for the detection of significant circadian rhythms in locomotor activity: S. typhlops, an extremely troglomophic species, presented the lowest number of significant components in the circadian range (only one individual out of eight in DD1 and three other fish in LD), all weak (low values of spectral power). Higher incidence of circadian components was observed for P. kronei - only one among six studied catfish without significant circadian rhythms under DD1 and DD2; spectral powers were generally high. Intermediate situations were observed for the remaining species, however all of them presented relatively strong significant rhythms under LD. Residual oscillations (circadian rhythms in DD2) were detected in at least part of the studied individuals of all species but S. typhlops, without a correlation with spectral powers of LD rhythms, i.e., individuals exhibiting residual oscillations were not necessarily those with the strongest LD rhythms. In conclusion, the accumulated evidence for troglobitic fishes strongly supports the hypothesis of external, environmental selection for circadian locomotor rhythms.

Evaluation of different selective media for enumeration of probiotic micro-organisms in combination with yogurt starter cultures in fermented milk

The aim of this study was to assess selective plating methodologies for the enumeration and identification of Streptococcus thermophilus, Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus acidophilus, Lactobacillus rhamnosus and Bifidobacterium animalis ssp. lactis in fermented milks. Seven agar media (MRS with added sorbitol, clindamycin or vancomycin, acidified MRS, RCA with added aniline blue and dicloxacilin, M17 and ST) were evaluated. The results showed that RCA dicloxacilin agar was suitable for the selective enumeration of B. animalis ssp. lactis in fermented milk. Either MRS (acidified) or M17 agar could be used for enumeration of L. delbrueckii ssp. bulgaricus and S. thermophilus, respectively. MRS media containing antibiotics were effective for the enumeration of the probiotic organisms (L. rhamnosus and L. acidophilus) inoculated in fermented milks.

Gases and volatile compounds associated with micro-organisms in blown pack spoilage of Brazilian vacuum-packed beef

This study correlated the composition of the spoilage bacterial flora with the main gaseous and volatile organic compounds (VOCs) found in the package headspace of spoiled, chilled, vacuum-packed meat. Fifteen chilled, vacuum-packed beef samples, suffering from blown pack spoilage, were studied using 16S rRNA clone sequencing. More than 50% of the bacteria were identified as lactic acid bacteria (LAB), followed by clostridia and enterobacteria. Fifty-one volatile compounds were detected in the spoiled samples. Although the major spoilage compounds were identified as alcohols and aldehydes, CO2 was identified as the major gas in the spoiled samples by headspace technique. Different species of bacteria contribute to different volatile compounds during meat spoilage. LAB played an important role in blown pack deterioration of the Brazilian beef studied.

Zooplankton biomass estimation from digitized images: a comparison between subtropical and Antarctic organisms

The measurement of mesozooplankton biomass in the ocean requires the use of analytical procedures that destroy the samples. Alternatively, the development of methods to estimate biomass from optical systems and appropriate conversion factors could be a compromise between the accuracy of analytical methods and the need to preserve the samples for further taxonomic studies. The conversion of the body area recorded by an optical counter or a camera, by converting the digitized area of an organism into individual biomass, was suggested as a suitable method to estimate total biomass. In this study, crustacean mesozooplankton from subtropical waters were analyzed, and individual dry weight and body area were compared. The obtained relationships agreed with other measurements of biomass obtained from a previous study in Antarctic waters. Gelatinous mesozooplankton from subtropical and Antarctic waters were also sampled and processed for body area and biomass. As expected, differences between crustacean and gelatinous plankton were highly significant. Transparent gelatinous organisms have a lower dry weight per unit area. Therefore, to estimate biomass from digitized images, pattern recognition discerning, at least, between crustaceans and gelatinous forms is required.