Production of mucic acid from pectin-derived D-galacturonic acid: a review / 生物工程学报

Mucic acid is a hexaric acid that can be biosynthesized by oxidation of D-galacturonic acid, which is the main constituent of pectin. The structure and properties of mucic acid are similar to that of glucaric acid, and can be widely applied in the preparation of important platform compounds, polymers and macromolecular materials. Pectin is a cheap and abundant renewable biomass resource, thus developing a process enabling production of mucic acid from pectin would be of important economic value and environmental significance. This review summarized the structure and hydrolysis of pectin, the catabolism and regulation of D-galacturonic acid in microorganisms, and the strategy for mucic acid production based on engineering of corresponding pathways. The future application of mucic acid are prospected, and future directions for the preparation of mucic acid by biological method are also proposed.

A plate method for rapid screening of Ketogulonicigenium vulgare mutants for enhanced 2-keto-l-gulonic acid production

Abstract A new plate method was developed for rapid screening of Ketogulonicigenium vulgare mutants overproducing 2-keto-l-gulonic acid (2-KLG). The screening methodology took the advantage of the acidity caused by 2-KLG, which changes the color of bromothymol blue (pH indicator) from blue to yellow. Using the proposed method, a mutant, K. vulgare 65, was selected from 20,000 colonies produced by a strain subjected to spaceflight mutagenesis. When co-cultured with Bacillus megaterium 2980 in 20-L fermenters, K. vulgare 65 showed a high conversion rate (94.45%) of l-sorbose to 2-KLG. In contrast to the traditional screening method, this one significantly improved the frequency of obtaining positive mutants. The proposed plate screening method is cost-effective and easy to run and is thus useful for the isolation and screening of K. vulgare mutants overproducing 2-KLG.

Fitness analysis between the L-sorbosone dehydrogenase modules and Ketogulonigenium vulgare chassis / 生物工程学报

Ketogulonigenium vulgare is an acid-producing strain in the process of two-step vitamin C fermentation. L-sorbosone dehydrogenase (SNDH) is one of the key enzymes during the biosynthesis of 2-keto-L-gulonic acid (2-KGA), the precursor of vitamin C. However, the catalytic mechanism of SNDH is unclear. According to the whole genome sequencing of K. vulgare, two genes encoding sorbosone dehydrogenases, one derived from the chromosome (named as sndhg) and one from plasmid (named as sndhp), were introduced into an industrial strain K. vulgare. The overexpression of gene sndhg had hardly effect on 2-KGA production, and the overexpression of gene sndhp produced an obvious byproduct in the fermentation broth. Combinational expression of sndhg/sndhp with pqqA (obtaining sndhg-pqqA and sndhp-pqqA modules) in K. vulgare resulted in the similar fermentation phenotype to two previous strains. After serial sub-cultivation of co-cultured Bacillus endophyticus with each engineered K. vulgare for 50 d, the conversion rate of 2-KGA increased by 15.4%, 179%, 0.65% and 125% compared with that of the parental K. vulgare with B. endophyticus. This study shows that adaptive evolution of microbial consortium is an effective strategy to increase the fitness between functional modules and chassis, thus quickly getting better strains for production of 2-KGA.

Influence of magnification and superimposition of structures on cephalometric diagnosis

OBJECTIVE: The purpose of this study was to assess the influence of magnification and superimposition of structures on CBCT-generated lateral cephalometric radiographs (LCR) using different segments of the cranium. METHODS: CBCT scans of 10 patients were selected. Four LCR were generated using Dolphin Imaging(r) software: full-face, right side, left side and center of the head. A total of 40 images were imported into Radiocef Studio 2(r), and the angles of the most common cephalometric analyses were traced by the same observer twice and within a 10-day interval. Statistical analyses included intraexaminer agreement and comparison between methods by means of intraclass correlation coefficient (ICC) and Bland-Altman agreement tests. RESULTS: Intraexaminer agreement of the angles assessed by ICC was excellent (> 0.90) for 83% of measurements, good (between 0.75 and 0.90) for 15%, and moderate (between 0.50 and 0.75) for 2% of measurements. The comparison between methods by ICC was excellent for 68% of measurements, good for 26%, and moderate for 6%. Variables presenting wider confidence intervals (> 6o) in the Bland-Altman tests, in intraexaminer assessment, were: mandibular incisor angle, maxillary incisor angle, and occlusal plane angle. And in comparison methods the variables with wider confidence interval were: mandibular incisor, maxillary incisor, GoGn, occlusal plane angle, Frankfort horizontal plane (FHP), and CoA. CONCLUSION: Superimposition of structures seemed to influence the results more than magnification, and neither one of them significantly influenced the measurements. Considerable individual variability may occur, especially for mandibular and maxillary incisors, FHP and occlusal plane. .

OBJETIVO: o objetivo do presente estudo foi avaliar a influência da sobreposição estrutural e da magnificação nas radiografias cefalométricas laterais (RCL) geradas por meio de tomografias computadorizadas de feixe cônico (TCFC), usando diferentes segmentos do crânio. MÉTODOS: foram selecionadas 10 tomografias de pacientes. Quatro RCL foram geradas usando Dolphin Imaging, sendo face total, lado direito, lado esquerdo e o centro da cabeça. Um total de 40 imagens foi importado para o Radiocef Studio, e os ângulos das análises cefalométricas mais comuns foram medidos pelo mesmo observador, duas vezes, em um intervalo de 10 dias. As análises estatísticas incluíram concordância intraexaminador e comparação entre os métodos por meio do coeficiente de correlação intraclasse (ICC) e testes de concordância de Bland-Altman. RESULTADOS: a concordância intraexaminador dos ângulos avaliados pelo ICC foi excelente (> 0,90) para 83% das medições, boa (entre 0,75 e 0,90) para 15%, e moderada (entre 0,50 e 0,75) para 2% das medições. A comparação entre os métodos por ICC foi excelente para 68% das medições, boa para 26% e moderada para 6%. As variáveis que apresentaram intervalos de confiança mais amplos (> 6°) nos testes de Bland-Altman, na avaliação intraexaminador, foram: incisivo superior, incisivo inferior e plano oclusal, enquanto nos métodos de comparação, as variáveis com intervalos de confiança mais amplos foram: incisivo inferior, incisivo superior, GoGn, ângulo do plano oclusal, plano horizontal de Frankfort e CoA. CONCLUSÃO: a sobreposição estrutural pareceu influenciar os resultados mais do que a magnificação, mas os métodos não influenciaram significativamente as medições. Considerável variabilidade individual pode ocorrer especialmente para os incisivos superiores e inferiores, plano horizontal de Frankfort e plano oclusal. .

Metabolite Profiling during Fermentation of Makgeolli by the Wild Yeast Strain Saccharomyces cerevisiae Y98-5

Makgeolli is a traditional Korean alcoholic beverage. The flavor of makgeolli is primarily determined by metabolic products such as free sugars, amino acids, organic acids, and aromatic compounds, which are produced during the fermentation of raw materials by molds and yeasts present in nuruk, a Korean fermentation starter. In this study, makgeolli was brewed using the wild yeast strain Saccharomyces cerevisiae Y98-5, and temporal changes in the metabolites during fermentation were analyzed by ultra-high-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry. The resultant data were analyzed by partial least squares-discriminant analysis (PLS-DA). Various metabolites, including amino acids, organic acids, sugar alcohols, small peptides, and nucleosides, were obviously altered by increasing the fermentation period. Changes in these metabolites allowed us to distinguish among makgeolli samples with different fermentation periods (1, 2, 3, 6, 7, and 8 days) on a PLS-DA score plot. In the makgeolli brewed in this study, the amounts of tyrosine (463.13 microg/mL) and leucine (362.77 microg/mL) were high. Therefore, our results indicate that monitoring the changes in metabolites during makgeolli fermentation might be important for brewing makgeolli with good nutritional quality.

Systems Biological Approaches Reveal Non-additive Responses and Multiple Crosstalk Mechanisms between TLR and GPCR Signaling

A variety of ligands differ in their capacity to bind the receptor, elicit gene expression, and modulate physiological responses. Such receptors include Toll-like receptors (TLRs), which recognize various patterns of pathogens and lead to primary innate immune activation against invaders, and G-protein coupled receptors (GPCRs), whose interaction with their cognate ligands activates heterotrimeric G proteins and regulates specific downstream effectors, including immuno-stimulating molecules. Once TLRs are activated, they lead to the expression of hundreds of genes together and bridge the arm of innate and adaptive immune responses. We characterized the gene expression profile of Toll-like receptor 4 (TLR4) in RAW 264.7 cells when it bound with its ligand, 2-keto-3-deoxyoctonate (KDO), the active part of lipopolysaccharide. In addition, to determine the network communications among the TLR, Janus kinase (JAK)/signal transducer and activator of transcription (STAT), and GPCR, we tested RAW 264.7 cells with KDO, interferon-beta, or cAMP analog 8-Br. The ligands were also administered as a pair of double and triple combinations.

Effects of broccoli extract on biodistribution and labeling blood components with 99mTc-GH / Efeitos do extrato de brócolis na biodistribuição e marcação dos componentes do sangue com 99mTc-GH

PURPOSE: People consume vegetables without the knowledge of the side effects of the biological and chemical contents and interactions between radiopharmaceuticals and herbal extract. To this end, current study is focused on the effects of broccoli extract on biodistribution of radiolabeled glucoheptonate (99mTc-GH) and radiolabeling of blood components. METHODS: GH was labeled with 99mTc. Quality control studies were done utilizing TLC method. Biodistribution studies were performed on male rats which were treated via gavage with either broccoli extract or SF as control group for 15 days. Blood samples were withdrawn from rats' heart. Radiolabeling of blood constituents performed incubating with GH, SnCl2 and 99m Tc. RESULTS: Radiochemical yield of 99mTc-GH is 98.46±1.48 percent (n=8). Biodistribution studies have shown that according to the control, the treated group with broccoli has approximately 10 times less uptake in kidney. The percentage of the radioactivity ratios of the blood components is found to be same in both groups. CONCLUSIONS: Although there is no considerable effect on the radiolabeling of blood components, there is an outstanding change on the biodistribution studies especially on kidneys. The knowledge of this change on kidney uptake may contribute to reduce the risk of misdiagnosis and/or repetition of the examinations in Nuclear Medicine.

OBJETIVO: As pessoas consomem verduras sem o conhecimento dos efeitos colaterais dos conteúdos biológicos e químicos e interações entre os medicamentos radiofarmacêuticos e os extratos vegetais. Para este fim, o estudo atual é focado sobre os efeitos do extrato de brócolis na biodistribuição do fármaco glucoheptonato (99mTc-GH) e da marcação de componentes do sangue. MÉTODOS: GH foi marcado com 99mTc. Estudos de controle de qualidade foram feitos utilizando o método do TLC. Os estudos de biodistribuição foram realizados em ratos machos que foram tratados por gavagem com um extrato de brócolis ou SF como grupo controle para 15 dias. Amostras de sangue foram retiradas do coração de ratos. Marcação de constituintes sanguíneos realizados incubação com SnCl2 GH e 99mTc. RESULTADOS: Radioquímica rendimento de 99mTc-GH é 98,46 ± 1,48 por cento (n = 8). Os estudos de biodistribuição mostraram que de acordo com o controle, o grupo tratado com brócolis tem aproximadamente 10 vezes menor absorção no rim. O percentual do ratio de radioatividade dos componentes do sangue é encontrado para ser igual nos dois grupos. CONCLUSÕES: Embora não haja nenhum efeito considerável sobre a marcação dos componentes do sangue há uma mudança notável na biodistribuição especialmente nos rins. O conhecimento desta mudança na captação de rim pode contribuir para reduzir o risco de erro diagnóstico e/ou a repetição dos exames de Medicina Nuclear.

Suppression of CFTR-mediated Cl- Secretion of Airway Epithelium in Vitamin C-deficient Mice

Hyperoxic ventilation induces detrimental effects on the respiratory system, and ambient oxygen may be harmful unless compensated by physiological anti-oxidants, such as vitamin C. Here we investigate the changes in electrolyte transport of airway epithelium in mice exposed to normobaric hyperoxia and in gulonolacton oxidase knock-out (gulo[-/-]) mice without vitamin C (Vit-C) supplementation. Short-circuit current (Isc) of tracheal epithelium was measured using Ussing chamber technique. After confirming amiloride-sensitive Na+ absorption (DeltaIsc,amil), cAMP-dependent Cl- secretion (DeltaIsc,forsk) was induced by forskolin. To evaluate Ca2+-dependent Cl- secretion, ATP was applied to the luminal side (DeltaIsc,ATP). In mice exposed to 98% PO2 for 36 hr, DeltaIsc,forsk decreased, DeltaIsc,amil and DeltaIsc,ATP was not affected. In gulo(-/-) mice, both DeltaIsc,forsk and DeltaIsc,ATP decreased from three weeks after Vit-C deprivation, while both were unchanged with Vit-C supplementation. At the fourth week, tissue resistance and all electrolyte transport activities were decreased. An immunofluorescence study showed that the expression of cystic fibrosis conductance regulator (CFTR) was decreased in gulo(-/-) mice, whereas the expression of KCNQ1 K+ channel was preserved. Taken together, the CFTR-mediated Cl- secretion of airway epithelium is susceptible to oxidative stress, which suggests that supplementation of the antioxidant might be beneficial for the maintenance of airway surface liquid.

Enhancement of 2-keto-L-gulonic acid production using three-stage pH control strategy / 生物工程学报

The aim of this study was to improve the 2-keto-L-gulonic acid (2-KLG) production efficiency by Ketogulonicigenium vulgare and Bacillus megaterium by using multi-stage pH control strategy. The effect of pH on the cell growths and 2-KLG production showed that the optimum pH for K. vulgare and B. megaterium cell growth were 6.0 and 8.0, respectively, while the optimum pH for 2-KLG production was 7.0. Based on the above results, we developed a three-stage pH control strategy: the pH was kept at 8.0 during the first 8 h, then decreased to 6.0 for the following 12 h, and maintained at 7.0 to the end of fermentation. With this strategy, the titer, productivity of 2-KLG and L-sorbose consumption rate were achieved at 77.3 g/L, 1.38 g/(L x h) and 1.42 g/(L x h), respectively, which were 9.7%, 33.2% and 25.7% higher than the corresponding values of the single pH (pH 7.0) control model.

Enhancing 2-keto-L-gulonic acid production under hyperosmotic stress by adding sucrose / 生物工程学报

This study aimed to further enhance 2-keto-L-gulonic acid (2-KLG) production efficiency. A strategy for enhancing Ketogulonigenium vulgare growth and 2-KLG production by improving B. megaterium growth with sucrose was developed based on the time course of osmolality during 2-KLG industrial scale fermentation and effects of osmolality on cells growth and 2-KLG production. Results showed that the accumulation of 2-KLG and the feeding of alkaline matter led to an osmolality rise of 832 mOsmol/kg in the culture broth. High osmotic stress (1 250 mOsmol/kg) made the growth ofB. megaterium and K. vulgare decreased 15.4% and 31.7%, respectively, and consequently the titer and productivity of 2-KLG reduced 67.5% and 69.3%, respectively. When supplement sucrose under high osmotic condition (1 250 mOsmol/kg), B. megaterium growth was significantly improved, with the result that 2-KLG production was increased 87%. Furthermore, by applying this sucrose addition strategy further to batch fermentation in 3 L fermentor, the productivity of 2-KLG increased 10.4%, and the duration of fermentation declined 10.8%. The results presented here provide a potential strategy for enhancing the target metabolites produced by mixed strains at environmental stress.

Effect of High Glucose on the Oxidative Stress in Trabecular Meshwork Cells

PURPOSE: To investigate the effect of high glucose (HG) on the oxidative stress in cultured human trabecular meshwork cells (HTMC). METHODS: Primarily cultured HTMC were exposed to low glucose (5 mM) and HG (25 mM) for 7 days. Additionally, 1 mM L-arginine, 5 mM DAHP, 10 microgram/ml insulin, 100 micrometer L-ascorbic acid, 10, and 100 micrometer sepiapterin were co-exposed. The cellular survival and nitric oxide (NO) production were assessed by MTT assay and Griess assay, respectively. Superoxide production was measured by modified cytochrome c assay. RESULTS: HG did not affect the survival of cultured HTMC significantly. HG decreased NO production. Co-exposed DAHP decreased but DAHP and insulin increased NO production. In addition, HG increased superoxide production, which was decreased by insulin, L-ascorbic acid, and sepiapterin. CONCLUSIONS: HG decreased NO production accompanied with increased superoxide production in HTMC. Thus HG induces oxidative stress in HTMC and may cause cellular dysfunction and damage of the trabecular meshwork.

Lactic acid fermentative production using waste from the harvest of green sugar cane as a substrate

Para la producción fermentativa de ácido láctico se evaluaron como sustrato residuos de cosecha de caña de azúcar (variedad CC85-92). Las fermentaciones se realizaron a 32ºC y pH 6,0, utilizando jugos obtenidos de hojas y cogollos (JTL), y Lactococcus lactis subs. lactis aislado de caña de azúcar de la misma variedad. En las fermentaciones se midieron la concentración de ácido láctico (LA), la conversión de sustrato (SC), la concentración de biomasa, la velocidad de formación de producto (rp) y el rendimiento (Yp/s), y los resultaron se compararon con fermentaciones que utilizaron la misma cepa y medio de cultivo comercial MRS adicionado de glucosa hasta 60g.l-¹. Utilizando JTL se pueden obtener concentraciones de ácido láctico por encima de 28,5g.l-¹ y rendimientos de 0,85g. g-¹ en 48 horas de fermentación. Los sustratos JTL y MRS mostraron diferencias estadísticamente significativas en Yp/s, SC y concentración de biomasa, y diferencias estadísticamente no significativas en LA y rp. Los resultados sugieren que los residuos de cosecha de caña de azúcar pueden ser utilizados como materia prima barata para la producción fermentativa de ácido láctico.

Purification of L-sorbose/L-sorbosne dehydrogenase from Ketogulonigenium vulgare and construction and selection of genomic library / 生物工程学报

L-sorbose/L-sorbosone dehydrogenase from Ketogulonigenium vulgare S2 can transform L-sorbose to 2-KLG, which is widely used in production of Vitamin C. In order to obtain the engineering strain producing L-sorbose/L-sorbosone dehydrogenase and simplify the fermentation technology, firstly, this enzyme was purified by the methods of ammonium sulfate precipitation, DEAE Sepharose Fast Flow and Q Sepharose High Performance. Then, the purified L-sorbose/L-sorbosone dehydrogenase was injected to rabbit to obtain antibody. Next, the genomic library of Ketogulonigenium vulgare S2 was constructed by inserting the restriction fragments of chromatosomal DNA digested with Sau3A I into cosmid pKC505 vector digested by Hpa I and Pst I, which were packed with lamda phage package protein and transferred into E. coli DH5alpha in vitro. Finally, the positive strain K719# was selected from more than 12,000 clones via Dot-ELISA. Through the test of SDS-PAGE and thin layer chromatography, the results showed that the engineering strain K719# had the same biological activity as Ketogulonigenium vulgare S2 after adding coenzyme PQQ.

Imaging using Tc99m-tetrofosmin for the detection of the recurrence of brain tumour: a comparative study with Tc99m-glucoheptonate.

BACKGROUND: In the past "blood-brain barrier" agents such as Tc99m-glucoheptonate were routinely used for the diagnosis of brain tumours. Of late, agents used for studying myocardial perfusion namely, Tc99m-tetrofosmin, Thallium-201, and Tc99m-sestamibi have replaced the "blood-brain barrier agents " when imaging is undertaken for the detection of the recurrence of brain tumours. However, the incremental diagnostic information provided by Tc99m-tetrofosmin when compared with a blood brain barrier agent in the diagnosis of recurrent brain tumour has not been evaluated till date. AIMS: The study was carried out to substantiate whether Tc99m-tetrofosmin provides any incremental diagnostic information not provided by the blood brain barrier agent Tc99m-glucoheptonate. MATERIAL AND METHODS: Brain SPECT scans were performed using Tc99m-tetrofosmin and Tc99m-glucoheptonate in 126 patients of recurrent brain tumour. Bio-distribution and uptake properties of both the tracers were analysed by measuring relative uptake of both the tracers in tumour compared to background (T/B ratio), nasopharynx (T/N ratio) and scalp (T/S ratio). STATISTICAL ANALYSIS: Descriptive statistics were calculated for each variable. Pearson's correlation coefficient was applied to see agreement of the continuous variables. Paired t test was used to evaluate the difference between two means. RESULTS: Uptake properties of both the tracers were analysed in 105 patients in whom both Tc99m-tetrofosmin and Tc99m-glucoheptonate showed concentration. The remaining 21 patients in whom the tumour mass did not show Tc99m-tetrofosmin concentration were excluded from the study. Mean T/B ratio, T/N ratio and T/S ratio was 5.83 + 2.09 and 5.99 + 2.26, 0.53 + 0.21 and 0.55 + 0.22 and 1.11 + 0.60 and 1.26 + 0.52 for Tc99m-tetrofosmin and Tc99m-glucoheptonate respectively. No statistically significant difference between T/B ratio and T/N ratio of Tc99m-tetrofosmin and Tc99m-glucoheptonate was found; p values were 0.25 and 0.83 respectively. However there was significant difference (P=0.006) between the T/S ratio of Tc99m-tetrofosmin and that of Tc99m-glucoheptonate. CONCLUSION: Tc99m-tetrofosmin does not provide any incremental diagnostic information not provided by the blood brain barrier agent Tc99m-glucoheptonate.

Craving e consumo de doce em pacientes dependentes de cocaína crack: um estudo clínico de observação / Craving and candy consumption in cocaine crack dependent patients: an observational clinical study

O objetivo deste estudo clínico foi observar sobre o consumo de doce para superar o craving em pacientes dependentes de cocaína-crack, voluntariamente internados em comunidade terapêutica.Foram estabelecidos critérios de inclusão e exclusão para constituir a amostra e critérios na entrevista para a coleta de dados. Os dados foram analisados em frequências absolutas e frequências relativas. Da amostra obtida(n=26), 42,3 por cento referiram não sentir craving durante o período de abstinência, enquanto que 26,9 por cento relataram sentir craving e 30,7 por cento que afirmaram superar o craving consumindo um alimento doce. Foram elaboradas possíveis explicações sobre a superação do craving consumindo doce.

The protective effects and its underlying mechanism of 2,4-diamino-6-hydroxy-pyrimidine on postburn Staphylococcus aureus sepsis in rats / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the protective effect and its underlying mechanism of 2,4-diamino-6-hydroxy-pyrimidine (DAHP), an inhibitor of GTP-cyclohydrolase I (GTP-CHI), on postburn Staphylococcus aureus (S. aureus) sepsis in rats.</p><p><b>METHODS</b>Fifty-six Wistar rats were randomly divided into four groups, i.e. normal control, scalding control, postburn sepsis group and DAHP treatment group. Tissue samples from liver, kidneys, lungs and heart were aseptically taken, and in which the GTP-CHI and inducible nitric oxide synthase (iNOS) contents and the mRNA expression of tumor necrosis factor-alpha (TNFalpha) were determined. Furthermore, biopterin (BH(4)) and nitric oxide (NO) levels in these tissue were also measured.</p><p><b>RESULTS</b>After the scalding injury followed by bacterial challenge, the GTP-CHI gene expression and biopterin levels were significantly increased in all tissue sampled, and so were iNOS mRNA expression and NO (P < 0.01), especially in liver and lungs. The expressions of GTP-CHI mRNA and iNOS mRNA and the production of BH(4) and NO in all tissue were evidently inhibited by the pretreatment with DAHP (P < 0.05 approximately 0.01). At the same time, the TNFalpha expression was also obviously decreased. In addition, The mortality at 6 hr in rats of DAHP treatment group was decreased.</p><p><b>CONCLUSION</b>The prognosis of the scalding rats complicated by sepsis caused by G(+) bacteria could be improved by DAHP pretreatment, which might be related to the inhibition of the production of BH(4) and NO by DAHP.</p>

Formulation of culture medium for growth of microbes from the sugar cane industry and use of cetyltrimethylammonium bromide as antimicrobial agent

Foi desenvolvido um meio adequado para cultivo de microrganismos importantes na indústria de acúcar e alcool. A eficácia do meio foi determinada medindo-se os parâmetros de crescimento dos principais microrganismos contaminantes do caldo de cana que säo exigentes quanto aos fatores de crescimento. Esse meio teve base no caldo de cana desde que a sua finalidade era avaliaçäo dos agentes antimicrobianos comumente usados no controle de contaminaçäo da indústria sucro-alcooleira. Como exemplo de sua utilizaçäo, o comportamento do brometo de cetiltrimetilamônio (CTAB) no meio de cana 11 foi analisado quanto à sua atividade sobre os microrganismos selecionados. Bactérias do ácido acético e do ácido láctico foram os mais susceptíveis seguidas de leveduras, Pseudomonas acidovorans e depois pelas enterobactérias. Algumas Pseudomonas (Pseudomonas aeruginosa, Ps. cepacia e Ps. mendocina) foram extremamente resistentes no CTAB, provavelmente em virtude da impermeabilidade do invólucro celular. A eficácia do CTAB em concentraçöes muito baixas sobre os microrganismos de interesse à indústria sucro-alcooleira pode ser medida por essa técnica

Açúcar: o tóxico adoçante / Sugar: the poisonous sweet

O objetivo deste trabalho é quantificar o consumo de açúcar, identificar os fatores determinantes deste e avaliar mudanças de atitudes dos alunos do curso profissionalizante da Faculdade de Odontologia de Pernambuco, frente ao pensamento corrente de que a ingestäo de sacarose acarreta danos à saúde. Variáveis individuais e ambientais que interferem no processo foram consideradas. Esta populaçäo revelou um elevado consumo de produtos contendo açúcar; no entanto, fatores determinantes do mesmo näo estäo relacionados com os conhecimentos científicos e crenças individuais, mas com a permissividade social do hábito e com as imagens ligadas à afetividade e à figura materna

Radiochemical quality control of kits labelled with Tc-99m produced at IPEN-CNEN/SP

Os radiofármacos marcados com 99mTc säo rotineiramente usados nos laboratórios de Medicina Nuclear. A maioria destes produtos utilizam Sn++ para reduzir o Tc(VII) a um estado de valência menor, facilitando a formaçäo de complexos na reaçäo. O sistema de cromatografia miniaturizada, realizado nos compostos marcados com 99mTc, usando Whatman 3MM (8x1 cm) ou (6x1 cm) como suporte, e NaCl 0,9// NaCl 30// metanol 85// e acetona como solventes, permite avaliar a pureza radioquímica em poucos minutos após a sua preparaçäo. Este método adaptado nos trabalhos de controle rotineiro determina além do TcO4 (pertecnetato) o 99mTc hidrolizado reduzido. Os conjuntos de reativos liofilizados para marcar com 99mTc produzidos no IPEN-CNEN/SP, säo MDP, DTPA, HSA, GHA, HIDA, pYRO, maa, miaa, s, Dextran-500, Cit. Sn. e Fit. Os ensaios de controle radioquímico foram realizados no primeiro dia após a sua preparaçäo e durante 12 meses para determinar a validade de seu uso. Todas as preparaçöes mostraram um alto rendimento (95-99//) de marcaçäo durante esse período de tempo