1 Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte MG, Brazil
2 Departamento de Bioquímica e Imunologia, Instituto de Ciências ...Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte MG, Brazil
3 Departamento de Bio-Interação, Universidade Federal da Bahia, Salvador BA, Brazil
4 Universidade Estadual Vale do Acaraú, Sobral CE, Brazil
5 Centro Nacional de Pesquisa de Caprinos, Empresa Brasileira de Pesquisa Agropecuária, Sobral CE, Brazil
Correspondence Vasco Azevedo vasco{at}icb.ufmg.br
Received 11 October 2006
Accepted 23 November 2006
Corynebacterium pseudotuberculosis is the aetiological agent of caseous lymphadenitis (CLA), a debilitating disease of sheep and goats. Accurate diagnosis of CLA primarily relies on microbiological examination, followed by biochemical identification of isolates. In an effort to facilitate C. pseudotuberculosis detection, a multiplex PCR (mPCR) assay was developed targeting three genes of this bacterium: the 16S rRNA gene, rpoB and pld . This method allowed efficient identification of 40 isolates of this bacterium that had been identified previously by biochemical testing. Analysis of taxonomically related species did not generate the C. pseudotuberculosis mPCR amplification profile, thereby demonstrating the assay's specificity. As little as 1 pg of C. pseudotuberculosis genomic DNA was detected by this mPCR assay, demonstrating the sensitivity of the method. The detection limit in clinical samples was estimated to be 10 3 c.f.u. C. pseudotuberculosis could be detected directly in pus samples from infected sheep and goats ( n =56) with a high diagnostic sensitivity (94.6 %). The developed assay significantly improves rapid C. pseudotuberculosis detection and could supersede bacteriological culture for microbiological and epidemiological diagnosis of CLA.
Abbreviations: CLA, caseous lymphadenitis; mPCR, multiplex PCR; PLD, phospholipase D.
The GenBank/EMBL/DDBJ accession number for the rpoB gene sequence of Arcanobacterium pyogenes is DQ680032.
Among the spinel oxides studied, NiAl
2O
4 showed the highest conversion in ethylbenzene dehydrogenation with CO
2 to produce styrene. The causes of the deactivation, as well as the regeneration ...ability, are discussed based on the structure and catalytic property relationships. Deactivation and recycling studies of NiAl
2O
4 show that the nature of coke is closely related to the activity and styrene selectivity.
Catalytic dehydrogenation of ethylbenzene with CO
2 to produce styrene was carried out on MAl
2O
4 (where M
=
Cu
2+, Ni
2+, or both), and also with pure NiO and CuO catalysts. The synthesized materials were characterized by various physico-chemical techniques and catalytic activity, coke deactivation, and recycling of spent catalysts were studied. The NiAl
2O
4 phase showed the highest activity under moderate conditions (activity
=
160
×
10
−3
mol
g
−1
h
−1; selectivity to styrene
=
90.7%). Pure NiO and CuO were virtually inactive in the reaction due to the easy reduction of the phases in these oxides. NiAl
2O
4, an active phase for the reaction, was cooperatively associated with Cu in a highly stable ternary system (Cu-Ni-Al). However, this association did not result in high conversion or selectivity. Analyses of the coked catalysts revealed the presence of carbon on the solid surface that was in the form of graphite and polyaromatics. Deactivation studies on NiAl
2O
4 proved that Ni
2+ sites were covered with a moderate amount of crystalline graphite that grew progressively and was subsequently eliminated by using higher CO
2/EB ratios. These results suggest that a reverse water shift reaction may be occurring when this solid is used. On the other hand, polyaromatic carbons were not eliminated and were the leading cause of the catalyst deactivation, rather than the physical degradation (reduction) of the solid. Recycling studies have demonstrated the high tendency of NiAl
2O
4 to regain the oxidation state of nickel, and thus, the styrene selectivity was maintained for over 40
h. The conditions leading to the highest conversion were a CO
2/EB ratio of 30 and a
T
=
550
°C at ambient pressure. Under these conditions, activities were comparable to those of Fe-K commercial catalysts for dehydrogenation, leading over the steam.
Investigations surrounding the variability of productivity in upwelling regions are necessary for a better understanding the physical–biological coupling in these regions by monitoring systems of ...environmental impacts according to the needs of the regional coastal management. Using a spatial and temporal database from National Centers for Environmental Prediction (NCEP) and National Center for Atmospheric (NCAR) Research reanalysis, Quick Scatterometer vector wind, and surface stations from the Southeast coast of Brazil, we investigate the meteorological influences due to the large-scale systems in the variability of the nutrient and larvae concentration, and chlorophyll
a
, describing statistically relationships between them in upwelling regions. In addition, we used multivariate analysis, such as PCA and clustering to verify spatial and temporal variances and describe more clear the structure and composition of the ecosystem. Correlation matrix analyses were applied for different water masses present in the study area to identify the relations between physical and biogeochemical parameters in a region, where frequently upwelling occur. Statistical approaches and seasonal variability show that the period of November to March is more sensitive to nutrients (1.20 mg/m
3
for chlorophyll
a
, 2.20 μmol/l for total nitrogen and 5.5 ml/l for DO) and larvae concentrations (120 org/m
3
for most of the larvae, except for cirripedia that presented values around 370 org/m
3
) relating to the influence of large and mesoescale meteorological patterns. The spatial and temporal variables analyzed with multivariate approach show meaningful seasonality variance of the physical and biological samples, characterizing the principal components responsible for this variance in spring and summer (upwelling period), emphasizing the monitoring of species as crustaceans and mussels that are present in the local economy. Then, the spring and summer season are characterized by high productivity due to the occurrence of upwelling in this period.
•The IR system is a fast and inexpensive alternative for food sample preparation.•Conditions of the element extractions are studied in details using chemometric tools.•A potential sample preparation ...approach for trace element analysis is proposed.
A new approach to the analysis of Cu, Fe, Mn and Zn in flaxseed was developed based on infrared-assisted acid digestion. Quantitation by flame atomic absorption spectrometry yields results in agreement with those arising from aggressive total decomposition using conventional microwave-assisted (MW) digestions. A full factorial design in two levels was applied to evaluate the impact of significant variables for all elements to determine optimal experimental conditions. A desirability function revealed these to be: 2.0g sample mass, 8mL of HNO3 and 8min of heating time in the IR system. Precision better than 10% (RSD) was obtained, superior to that of a combined IR-MW approach. Sample preparation based on IR-assisted digestion provides a rapid and inexpensive alternative to other conventional techniques for the analysis of complex samples and is able to accommodate relatively large masses of sample, alleviating potential homogeneity issues as well as enhancing detection power.
•Potential of fast solubilization of 2 g of sample using only HNO3.•Simple and low cost system with a halogen lamp was used as IR source.•Samples with different fat/protein ratios were used to study ...the system.•Factorial design and chemometric tools provide fast optimization of the system.
A fast sample preparation procedure based on use of infrared (IR) assisted heating for mineralization of soybean derived samples has been developed for their subsequent multielement analysis by inductively coupled plasma optical emission spectrometry (ICP-OES) and flame atomic absorption spectrometry (FAAS). A cold finger was examined for refluxing of acid vapors to determine its impact on efficiency and economy of digestion. The optimized procedure, based on 1 g subsamples, 8 mL of HNO3 (65% w/w) and exposure of the mixture to a 500 W IR source for 5 min without refluxing, permitted accurate determination of all analytes in NIST SRM 1568b (rice flour). Detection limits using ICP-OES were (µg/kg) 97, 1.0, 39, 185, 0.47 and 1200 for Ca, Cu, Fe, K, Mn and P, respectively, and 18 for Zn by FAAS. The IR-assisted digestion approach provided a low cost, easy to use system having great potential for implementation in routine analysis of trace elements in soybean and similar matrices.
An original total synthesis of the antiepileptic drug brivaracetam (BRV) is reported. The key step in the synthesis consists of an enantioselective photochemical Giese addition, promoted by ...visible-light and the chiral bifunctional photocatalyst Δ-RhS. Continuous flow conditions were employed to improve the efficiency and allow an easy scale-up of the enantioselective photochemical reaction step. The intermediate obtained from the photochemical step was converted into BRV by two different pathways, followed by one alkylation and amidation, thus giving the desired active pharmaceutical ingredients (API) in 44% overall yield, 9:1 diastereoisomeric ratio (dr) and >99:1 enantiomeric ratio (er).
The 1,3-dipolar cycloaddition of meso-tetrakis(pentafluorophenyl)porphyrin and its nickel complex, with the bulky azomethine ylide dipole was studied under mild conditions, and yielded chlorin and ...isobacteriochlorin derivatives self-prevented from aggregation. The reactions were performed at room temperature or 0°C, and we were able to establish a set of reaction conditions to obtain only the chlorin or the isobacteriochlorin. These compounds were evaluated in solution, and no aggregation was observed at less than 25mM (∼30mgmL−1) using 1H NMR experiments.
The importance of Clostridium perfringens for most wild animal species remains unclear. This study aimed to isolate and genotype C. perfringens in stool samples from free-living South American coati ...(Nasua nasua) in Brazil. Forty-six free-living N. nasua were trapped and stool samples were collected. Two different protocols for C. perfringens isolation were tested: direct plating onto selective agar and pre-enrichment in broth followed by plating in selective agar. Clostridium perfringens type A was isolated from 15 (32.6%) animals by direct plating and 36 (78.3%) animals by broth PE, and the rate of isolation was significantly different between these two methods (P < 0.01). Twelve of the 36 (33.3%) isolated strains by the PE protocol were positive for the β-2 toxin-encoding gene (cpb2) whereas the enterotoxin-encoding gene (cpe) and necrotic enteritis like-B toxin gene (netb) were not found. These results suggest that C. perfringens is commonly part of the microbiota of free-living coatis. Additionally, the use of a PE protocol appears to be essential for studies on C. perfringens in this species.
(
)
is a spore-forming bacterium responsible for nosocomial infections in humans. It is recognized as an important agent of diarrhea and colitis in several animal species and a possible zoonotic ...agent. Despite the known importance of
infection in humans and animals, no vaccine or other effective measure to control the disease is commercially available. A possible alternative treatment for
infection is the use of a nontoxigenic strain of
as a competitive exclusion agent. However, a thorough knowledge of this strain is necessary for this purpose. We selected
Z31, a nontoxigenic strain (PCR ribotype 009), for investigation because it prevents
infection in a hamster model.
The genome sequence of
Z31 is a circular chromosome of 4298,263 bp, with a 29.21 % GC content, encoding 4128 proteins, and containing 78 pseudogenes. This strain belongs to ST 3, clade 1, and has five phage regions in its genome. Genes responsible for resistance to tetracycline and erythromycin were detected and more importantly, Z31 also contains genes that promote spore production and stability, cell attachment, intestinal adherence, and biofilm formation.
In this study, we present the first complete genome sequence of nontoxigenic
strain Z31. When the Z31 genome was compared with those of other isolates available in GenBank, including a draft genome of a nontoxigenic strain, several unique regions were evident. Z31 contains no toxin genes, but encodes several non-toxin virulence factors, which may favor host colonization.
PDF
