Molecular identification and physiological characterization of Zymomonas mobilis strains from fuel-ethanol production plants in north-east Brazil.

Zymomonas mobilis has long attracted attention owing to its capacity to ferment hexose to ethanol. From a taxonomic viewpoint, Z. mobilis is a unique species of the genus Zymomonas, separated into three subspecies, Z. mobilis subsp. mobilis, Z. mobilis subsp. pomaceae and Z. mobilis subsp. francensis on the basis of physiological tests, which are often unreliable owing to the genetic proximity among these species. Currently, the use of molecular techniques is more appropriate for identification of these bacterial subspecies. In this study, the 32 strains of Z. mobilis present in the UFPEDA bacterial collection were characterized using molecular techniques, such as sequencing of the 16S rDNA gene and its theoretical restriction profile, classifying them as members of the subspecies, Z. mobilis subsp. mobilis. In addition, anaerobic cultivations were performed, which showed the biological diversity of the strains in terms of growth, sugar consumption and ethanol production. From these results, it was possible to identify the strain Z-2-80 as a promising bacterium for use in the fermentation process. SIGNIFICANCE AND IMPACT OF THE STUDY: Zymomonas mobilis is a bacterium of great relevance to biotechnology, owing to its capacity to ferment hexose to ethanol. On a molecular basis, 32 isolates were identified as Z. mobilis subsp. mobilis. However, intraspecific diversity was identified when these were grown under strictly anaerobic conditions. The results obtained from this study suggest a strain of Z. mobilis as an alternative for use in the fermentation process.

Photodynamic effect of zinc porphyrin on the promastigote and amastigote forms of Leishmania braziliensis.

Leishmaniasis is a neglected disease present in more than 88 countries. The currently adopted chemotherapy faces challenges related to side effects and the development of resistance. Photodynamic therapy (PDT) is emerging as a therapeutic modality for cutaneous leishmaniasis. Zn(ii) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (ZnTE-2-PyP4+, ZnP) is a cationic, water-soluble, zinc porphyrin-based photosensitizer whose photodynamic effect on Leishmania braziliensis was analyzed by evaluating the number of visibly undamaged and motile cells, cell membrane integrity, mitochondrial membrane potential, and ultrastructural damage. Treatment of parasites with ZnP and light induced damage in up to 90% of L. braziliensis promastigote cells. Propidium iodide labeling suggested the loss of plasma membrane integrity. In samples treated with ZnP and light, a hyperpolarization of the mitochondrial membrane potential was also observed. Ultrastructural evaluation of promastigotes after photodynamic treatment indicated a loss of cytoplasmic material and the presence of vacuoles. Scanning electron microscopy showed wrinkling of the plasma membrane and a reduced cell volume. Additionally, the number of amastigotes per macrophage was reduced by about 40% after photodynamic application. The treatment showed no considerable toxicity against mammalian cells. Therefore, the results indicated that PDT associated with ZnTE-2-PyP4+ represents a promising alternative to cutaneous leishmaniasis treatment.

Biomedical applications of glyconanoparticles based on quantum dots.

BACKGROUND: Quantum dots (QDs) are outstanding nanomaterials of great interest to life sciences. Their conjugation versatility added to unique optical properties, highlight these nanocrystals as very promising fluorescent probes. Among uncountable new nanosystems, in the last years, QDs conjugated to glycans or lectins have aroused a growing attention and their application as a tool to study biological and functional properties has increased. SCOPE OF REVIEW: This review describes the strategies, reported in the literature, to conjugate QDs to lectins or carbohydrates, providing valuable information for the elaboration, improvement, and application of these nanoconjugates. It also presents the main applications of these nanosystems in glycobiology, such as their potential to study microorganisms, the development of diseases such as cancer, as well as to develop biosensors. MAJOR CONCLUSIONS: The development of glyconanoparticles based on QDs emerged in the last decade. Many works reporting the conjugation of QDs with carbohydrates and lectins have been published, using different strategies and reagents. These bioconjugates enabled studies that are very sensitive and specific, with potential to detect and elucidate the glycocode expressed in various normal or pathologic conditions. GENERAL SIGNIFICANCE: Produce a quick reference source over the main advances reached in the glyconanotechnology using QDs as fluorescent probes.

Vitamin E nanoemulsion activity on stored red blood cells.

BACKGROUND: Stored red blood cells (RBCs) undergo numerous changes that have been termed RBC storage lesion, which can be related to oxidative damage. Vitamin E is an important antioxidant, acting on cell lipids. Thus, this study aimed to investigate vitamin E activity on stored RBCs. METHODS: We prepared a vitamin E nanoemulsion that was added to RBC units and stored at 4 °C. Controls, without vitamin E, were kept under the same conditions. Reactive oxygen species (ROS) production was monitored for up to 35 days of storage. RBC elasticity was also evaluated using an optical tweezer system. RESULTS: Vitamin E-treated samples presented a significant decrease in ROS production. Additionally, the elastic constant for vitamin E-treated RBCs did not differ from the control. CONCLUSION: Vitamin E decreased the amount of ROS in stored RBCs. Because vitamin E acts on lipid oxidation, results suggest that protein oxidation should also be considered a key factor for erythrocyte elastic properties. Thus, further studies combining vitamin E with protein antioxidants deserve attention, aiming to better preserve overall stored RBC properties.

Protein extraction method for the proteomic study of Zymomonas mobilis during production of ethanol and levans.

Zymomonas mobilis has aroused considerable interest owing to its rapid metabolism and efficiency in producing ethanol and by-products such as levans, sorbitol, and gluconic acid from simple sugars. We performed a proteomic analysis of Z. mobilis UFPEDA241 to provide a global profile of regulatory proteins. The choice of the methods of extraction and cell lysis are fundamental steps and of great importance for the detection and identification of intra- and extracellular proteins of a proteome. Strains were subjected to protein extraction methods using three different reagents: TRIzol, lysis buffer, and phenol. The optimum method was taken to be the one that produced the greatest quantity and quality of proteins in one dimension for further analysis in two dimensions during the production of ethanol and levans over 72 h. The results showed that the greatest amount of protein was obtained by the phenol method (1.44 ± 0.07 mg/mL), which was significantly different (P < 0.05) to the TRIzol (1.11 ± 0.01 mg/mL), and lysis buffer (0.93 ± 0.01 mg/mL) methods (both with P > 0.05). Fermentation at 20°C produced the highest level of levans, and using two-dimensional electrophoresis and mass spectrometry it was possible to identify 34 differentially expressed spots.

Identification of Angiostrongylus cantonensis and other nematodes using the SSU rDNA in Achatina fulica populations of Metro Manila.

Angiostrongylus cantonensis is a parasitic nematode that causes eosinophilic meningitis in humans. Accidental infection occurs by consumption of contaminated intermediates, such as the giant African land snail, Achatina fulica. This study surveyed the presence of A. cantonensis juveniles in A. fulica populations from 12 sites in Metropolitan Manila, Philippines using the SSU rDNA. Fourteen distinct sequences from 226 nematodes were obtained; of these, two matched A. cantonensis and Ancylostoma caninum, respectively, with 100% identity. Exact identities of the remaining twelve sequences could not be determined due to low percent similarities. Of the sequenced nematodes, A. cantonensis occurred with the highest frequency (139 out of 226). Most of these (131 out of 139) were collected in just one area in Quezon City. Nematode infection of A. fulica in this area and two others from Makati and another area in Quezon City, respectively, were highest, combining for 95% of the total infection. Ancylostoma caninum, on the other hand, was detected in four different sites. A. caninum is a canine parasite, and this is the first report of the nematode in A. fulica. These results cause public health concerns as both A. cantonensis and A. caninum are zoonotic to humans.

Genetic variability and resistance of cultivars of cowpea [Vigna unguiculata (L.) Walp] to cowpea weevil (Callosobruchus maculatus Fabr.).

The cowpea weevil (Callosobruchus maculatus Fabr.) is the most destructive pest of the cowpea bean; it reduces seed quality. To control this pest, resistance testing combined with genetic analysis using molecular markers has been widely applied in research. Among the markers that show reliable results, the inter-simple sequence repeats (ISSRs) (microsatellites) are noteworthy. This study was performed to evaluate the resistance of 27 cultivars of cowpea bean to cowpea weevil. We tested the resistance related to the genetic variability of these cultivars using ISSR markers. To analyze the resistance of cultivars to weevil, a completely randomized test design with 4 replicates and 27 treatments was adopted. Five pairs of the insect were placed in 30 grains per replicate. Analysis of variance showed that the number of eggs and emerged insects were significantly different in the treatments, and the means were compared by statistical tests. The analysis of the large genetic variability in all cultivars resulted in the formation of different groups. The test of resistance showed that the cultivar Inhuma was the most sensitive to both number of eggs and number of emerged adults, while the TE96-290-12-G and MNC99-537-F4 (BRS Tumucumaque) cultivars were the least sensitive to the number of eggs and the number of emerged insects, respectively.

Short term inhalation toxicity of a liquid aerosol of CdS/Cd(OH)2 core shell quantum dots in male Wistar rats.

Colloidal quantum dots (QD) show great promise as fluorescent markers. The QD used in this study were obtained in aqueous medium rather than the widely used colloidal QD. Both methodologies used for the production of QD are associated with the presence of heavy metals such as cadmium (Cd). Here we investigate the short-term inhalation toxicity of water-soluble core-shell CdS/Cd(OH)2 QD. Male Wistar rats were head-nose exposed for 6 h/day on 5 days at the technically maximum concentration (0.52 mg Cd/m³). Histological examination was performed directly after the last exposure. Additional rats were used for Cd organ burden determinations. Clinical parameters in blood, bronchoalveolar lavage fluid and lung tissue were determined 3 days after the last exposure. To analyze the reversibility or progression of effects, the examinations were performed again after a recovery period of 3 weeks. The results of the study indicate that CdS/Cd(OH)2 QD caused local neutrophil inflammation in the lungs that partially regressed after the 3-week recovery period. There was no evidence that QD were translocated to the central nervous system nor that a systemic acute phase response occurred.

Web-enabled registry of inherited bleeding disorders in Portugal: conditions and perception of the patients.

Local and national haemophilia registries are powerful instruments to support the healthcare and researchers and improve the communication between Comprehensive Haemophilia Diagnostic and Treatment Centres (HTCs) and patients. Hemo@care is an example of a Local Haemophilia Registry Systems (LHR_Sys) based on the Web, developed in collaboration with a HTC located in Portugal, to support the haemophilia treatments registry, collect and manage the clinical information and provide mechanisms to control the clotting factor concentrates (CFC) stock. To extend this solution (the hemo@care) to other Portuguese HTCs and consequently to meet the preconditions to create a National Haemophilia Registry Systems (NHR_Sys), a study based on a questionnaire was carried out at nationwide. This study aims to assess the conditions and motivations of people with haemophilia (PWH) geographically scattered throughout the country, to use a potential Web-enabled registry with the purpose of replacing the traditional paper-diaries, to understand their judgment about a potential NHR_Sys currently non-existent in Portugal, and at the same time, to characterize demographically and pathologically those people at the nationwide. The results based on the analysis of 168 responses (response rate of 31%) confirmed the high prevalence of the disease in haemophilia A (75%) compared with haemophilia B (11.3%) and a large incidence in the severe levels, or the existence of people with mild severity without diagnosis and treatment. Furthermore, the results also revealed the need, conditions and motivation for using a registry system by PWH; thus it is deemed to justify the extension of the hemo@care to other HTCs in Portugal and consequently to create the NHR_Sys.

Integrating user studies into computer graphics-related courses.

This paper presents computer graphics. Computer graphics and visualization are essentially about producing images for a target audience, be it the millions watching a new CG-animated movie or the small group of researchers trying to gain insight into the large amount of numerical data resulting from a scientific experiment. To ascertain the final images' effectiveness for their intended audience or the designed visualizations' accuracy and expressiveness, formal user studies are often essential. In human-computer interaction (HCI), such user studies play a similar fundamental role in evaluating the usability and applicability of interaction methods and metaphors for the various devices and software systems we use.

Uso de pinças ópticas para avaliação do potencial zeta de hemácias em EDTA, CPD-SAGM e estocadas / Use of optical tweezers for evaluation of szeta potential of red blood cells in EDTA, CPD-SAGM and stored in blood banks

A hemácia é carregada negativamente, principalmente devido ao ácido siálico que gera um potencial elétrico denominado Potencial Zeta que impede a aglutinação intravascular. Os testes de hemaglutinação na rotina transfusional, necessitam de substâncias potencializadoras, das quais muitas agem diminuindo o Potencial Zeta para se ter maior sensibilidade. Através da pinça óptica, ferramenta capaz de capturar células utilizando a luz, foi proposta uma metodologia para quantificar o potencial zeta e aplicar em hemácias coletadas com EDTA e estocadas em CPD-SAGM (visando avaliar alterações de cargas da membrana relacionadas a lesões de armazenamento. Os potenciais zeta em CPD-CAGM foram superiores (-14,8 mV) aos em EDTA (-7,9 mV) e decrescentes a partir do primeiro dia de armazenamento, estabilizando-se a partir da terceira semana com potencial zeta -7,6 mV. Hemácias com CPD-SAGM apresentaram potencial zeta maior, pois possivelmente este conservante evitou lesões mais significativas da membrana que poderiam alterar as cargas. A redução do potencial zeta no armazenamento pode ser consequência de enzimas liberadas de leucócitos lisados que tenham alterado as glicoforinas da membrana. A metodologia permitiu avaliar o potencial zeta em diferentes condições e poderá contribuir na padronização de técnicas de hemaglutinação com diferentes meios potencializadores e no melhor conhecimento das lesões de estocagem para fins transfusionais.

Studying taxis in real time using optical tweezers: applications for Leishmania amazonensis parasites.

Beads trapped by an optical tweezers can be used as a force transducer for measuring forces of the same order of magnitude as typical forces induced by flagellar motion. We used an optical tweezers to study chemotaxis by observing the force response of a flagellated microorganism when placed in a gradient of attractive chemical substances. This report shows such observations for Leishmania amazonensis, responsible for leishmaniasis, a serious disease. We quantified the movement of this protozoan for different gradients of glucose. We were able to observe both the strength and the directionality of the force. The characterization of the chemotaxis of these parasites can help to understand the mechanics of infection and improve the treatments employed for this disease. This methodology can be used to quantitatively study the taxis of any kind of flagellated microorganisms under concentration gradients of different chemical substances, or even other types of variable gradients such as temperature and pressure.

Some environmental and biological factors influencing the activity of entomopathogenic Bacillus on mosquito larvae in Brazil

The influence of environmental and biological factors on the efficacy of Bacillus thuringiensis serovar israelensis and B. sphaericus as mosquito larvicides are reviewed. The importance of strain dependence, cultivating media/methods, mosquito species/specificity, formulations and their relation to mosquito feeding habits, as well as temperature, solar exposure, larval density and concomitant presence of other aquatic organisms are addressed with reference to the present status of knowledge in Brazil.

Some environmental and biological factors influencing the activity of entomopathogenic Bacillus on mosquito larvae in Brazil.

The influence of environmental and biological factors on the efficacy of Bacillus thuringiensis serovar israelensis and B. sphaericus as mosquito larvicides are reviewed. The importance of strain dependence, cultivating media/methods, mosquito species/specificity, formulations and their relation to mosquito feeding habits, as well as temperature, solar exposure, larval density and concomitant presence of other aquatic organisms are addressed with reference to the present status of knowledge in Brazil.

Atividade predatoria de Helobdella triserialis lineata (Hirudinea: Glossiphonidae) sobre formas imaturas de Aedes fluviatilis e Culex quinquefasciatus (Diptera: Culicidae) em laboratorio. / Predatory activity of Helobdella triserialis lineata (Hirudinea: Glossiphonidae) on immature forms of Aedes fluviatilis and Culex quinquefasciatus (Diptera: Culicidae) in laboratory

Foi avaliada a atividade predatoria, em laboratorio, de Helobdella triserialis lineata (Hirudinea: Glossiphonidae) sobre ovos, larvas e pupas de Aedes fluviatilis e Culex quinquefasciatus (Diptera: Culicidae), bem como a influencia da presenca desses hirudineos sobre o comportamento de oviposicao das femeas das duas especies de mosquitos. Experimentos adicionais foram feitos testando a influencia da profundidade da agua e da sua salinidade sobre a capacidade predatoria dos hirudineos. Nas condicoes do experimento, foi observada predacao de larvas e pupas, porem nao de ovos das duas especies de dipteros. Numero estatisticamente menor de desovas foi depositado por femeas de Cx. quinquefasciatus em recipientes que continham hirudineos, nao ocorrendo o mesmo com femeas de Ae. fluviatilis. As diferentes profundidades de agua testadas nao interferiram na atividade predatoria de H. t. lineata e somente em concentracoes acima de 3% de NaC1 essa atividade mostrou-se bastante diminuida