Production of medium-chain-length polyhydroxyalkanoate by Pseudomonas oleovorans grown in sugary cassava extract supplemented with andiroba oil

Pseudomonas oleovorans were grown on sugary cassava extracts supplemented with andiroba oil for the synthesis of a mediumchain- length polyhydroxyalkanoate (PHA MCL). The concentration of total sugars in the extract was approximately: 40 g/L in culture 1, 15 g/L in cultures 2 and 3, and 10 g/L in culture 4. Supplementation with 1% andiroba oil and 0.2 g/L of (NH4)2HPO4 was performed 6.5 hours after growth in culture 3, and supplementation with the same amount of andiroba oil and 2.4 g/L of (NH4)2HPO4 was performed at the beginning of growth in culture 4. The synthesis resulted mainly in 3-hydroxy-decanoate and 3-hydroxy-dodecanoate units; 3-hydroxy-butyrate, 3-hydroxy-hexanoate; and 3-hydroxy-octanoate monomers were also produced but in smaller proportions. P. oleovorans significantly accumulated PHA MCL in the deceleration phase of growth with an oxygen limitation but with sufficient nitrogen concentration to maintain cell growth. The sugary cassava extract supplemented with andiroba oil proved to be a potential substrate for PHA MCL production.

Estudo microcalorimétrico da interação de tensoativos n-alquil-sulfato de sódio com tripsina a 298 k

Systematic study of the interactions of ionic surfactants with protein trypsin in buffer solution pH 3.5, 7.0 and 9.0, ionic strength 10 mM at 298 K was done using the microcalorimetric technique. In this study, anionic surfactant solutions of the sodium n-alkyl sulfates series (C8, C10, C12 and C14) were used. The enthalpy of interaction (ΔintHº) shows that the interaction of the surfactants C8, C10, C12 and C14 with trypsin in the solution pH 3.5 is an endothermic process with the value of ΔintHº decreasing linearly with increasing carbon chain length, which is attributed to the unfolding of the polypeptide chain. In the solution pH 7.0, we observed the same trend except for C14. In the solution pH 9.0, from C10 the enthapy of interaction didn't change with the increasing of the carbon chain length due to unfolding of the polypeptide. We concluded that when trypsin is folded, the enthalpy of interaction shows a linear relationship with the surfactant's hydrophobicity, in agreement with Traube's rule.

A técnica da reflectância difusa aplicada ao estudo da fluorescência de 2,3-naftalimidas n-substituídas com grupos alquila incluídas em b-ciclodextrina e adsorvidas em celulose microcristalina

The solution fluorescence of N-alkyl-2,3-naphthalimides (1-4) in polar protic and aprotic solvents was compared to the emission from solid samples resulting from the imide complexation with b-cyclodextrin or adsorption on the surface of microcrystalline cellulose. Solid samples of the inclusion complex 2,3-naphthalimides/b-cyclodextrin show maximum for fluorescence emission significantly different to the observed in methanolic solution. Beside this, a clear effect on the alkyl chain length could be observed for these samples which is probably due to differences in probe location inside the cyclodextrin cavity. The constancy for fluorescence quantum yield and fluorescence lifetime for the imides 1 - 4 adsorbed on microcrystalline cellulose suggests that, independently of the polarity of the solvent used for sample preparation, the probe is preferentially located on the cellulose surface. An increase of fluorescence quantum yield and fluorescence lifetime for solid samples, when compared to the values obtained in solution for the different solvents employed in this study (acetonitrile, methanol and water), is fully in accordance with a decrease of the probe mobility due to inclusion in b-cyclodextrin or to adsorption on cellulose.

Imobilização de lipases em filme de caseinato de sódio/glicerol: aplicação na síntese de ésteres

Lipases from different sources were immobilized in sodium caseinate/glycerol film and used in the esterification reactions of aliphatic acids with alcohols in the presence of organic solvents. Lipases from Pseudomonas sp and Rhizopus oryzae were selected and the influence of several parameters was analyzed, including: lipase loading, organic solvent polarity, reaction temperature, chain length of alcohol and acid and enzyme/support reuse. For comparison, free enzymes were used under similar experimental conditions.

Optimization of the carrot leaf dehydration aiming at the preservation of omega-3 fatty acids

The carrot leaf dehydration conditions in air circulation oven were optimized through response surface methodology (RSM) for minimizing the degradation of polyunsaturated fatty acids, particularly alpha-linolenic (LNA, 18:3n-3). The optimized leaf drying time and temperature were 43 h and 70 ºC, respectively. The fatty acids (FA) were investigated using gas chromatography equipped with a flame ionization detector and fused silica capillary column; FA were identified with standards and based on equivalent-chain-length. LNA and other FA were quantified against C21:0 internal standard. After dehydration, the amount of LNA, quantified in mg/100 g dry matter of dehydrated carrot leaves, were 984 mg.

Evaluation of the influence of base and alkyl bromide on synthesis of pyrazinoic acid esters through fatorial design

Pyrazinoic acid esters have been synthesized as prodrugs of pyrazinoic acid. In the literature, its preparation is reported through the reaction of pyrazinoyl chloride with alcohols and the reaction with DCC/DMAP. In this work, it is reported a 2² factorial design to evaluate the preparation of these esters through the substitution of alkyl bromides with carboxylate anion. The controlled factors were alkyl chain length of bromides (ethyl and hexyl) and the used base (triethylamine and DBU). Results revealed that the used base used has significant effect on yield, and alkyl bromide used has neither significant influence, nor its interaction effect with base.

Efecto del catión, del anión y del co-ión sobre la agregación de líquidos iónicos en solución acuosa

The aggregation behavior of thirteen 1-alkyl-3-methylimidazolium based ionic liquids in aqueous solution is presented, considering variations of the alkyl side chain length as well as the anionic moiety. Cation and anion molecular volumes are selected as appropriate molecular descriptors. Additionally, the existing relationship between critical micelle concentration (CMC) and electrolyte concentration in solution is established, aiming to clarify ion effects. CMC values were obtained by measuring electrical conductivity and surface tension. It was confirmed that aggregation of ionic liquids in aqueous solution and in presence of inorganic salts is affected by the factors developed in this study.

Estudio del coeficiente de reparto de ácidos carboxílicos grasos en sistemas modificados heptano/agua

The use of fatty acids (FAs) as amphiphiles is very important because they have a behaving similar to surfactants. The formulation for the preferential partition of these species was studied by varying the amount of salt at constant acid concentration. As the salt concentration increases, a Winsor I→III→II transition is observed for all the systems studied. Furthermore, the electrolyte concentration required to obtain the optimum formulation varies inversely with the chain length of the acid. The partition coefficient of the surfactant allows one to obtain thermodynamic information on the acid transfer process between the phases of the system.

Reversible flow of cholesteryl ester between high-density lipoproteins and triacylglycerol-rich particles is modulated by the fatty acid composition and concentration of triacylglycerols

We determined the influence of fasting (FAST) and feeding (FED) on cholesteryl ester (CE) flow between high-density lipoproteins (HDL) and plasma apoB-lipoprotein and triacylglycerol (TG)-rich emulsions (EM) prepared with TG-fatty acids (FAs). TG-FAs of varying chain lengths and degrees of unsaturation were tested in the presence of a plasma fraction at d > 1.21 g/mL as the source of CE transfer protein. The transfer of CE from HDL to FED was greater than to FAST TG-rich acceptor lipoproteins, 18% and 14%, respectively. However, percent CE transfer from HDL to apoB-containing lipoproteins was similar for FED and FAST HDL. The CE transfer from HDL to EM depended on the EM TG-FA chain length. Furthermore, the chain length of the monounsaturated TG-containing EM showed a significant positive correlation of the CE transfer from HDL to EM (r = 0.81, P < 0.0001) and a negative correlation from EM to HDL (r = -041, P = 0.0088). Regarding the degree of EM TG-FAs unsaturation, among EMs containing C18, the CE transfer was lower from HDL to C18:2 compared to C18:1 and C18:3, 17.7%, 20.7%, and 20%, respectively. However, the CE transfer from EMs to HDL was higher to C18:2 than to C18:1 and C18:3, 83.7%, 51.2%, and 46.3%, respectively. Thus, the EM FA composition was found to be the rate-limiting factor regulating the transfer of CE from HDL. Consequently, the net transfer of CE between HDL and TG-rich particles depends on the specific arrangement of the TG acyl chains in the lipoprotein particle core.

Polymerase chain reaction and restriction fragment length polymorphism analysis of the ITS2 region for differatiation of Brazilian Biomphalaria intermediate hosts of the Schistosoma mansoni

We sequenced the internal transcribed spacer 2 of the ribosomal DNA (ITS2-DNAr) from the three Schistosoma mansoni intermediate hosts in Brazil: Biomphalaria glabrata, Biomphalaria tenagophila and Biomphalaria straminea. Analysis of a restriction map from those sequences allowed us to select putative restriction enzymes able to identify the snail species under study. Four restriction enzymes were used and HpaII provided simple species-specific profiles easily visualized in polyacrylamide gels. The use of ITS2 is advantageous as it provides a small fragment of 460 bp which may be easily amplified by PCR. In the current work, we showed that the amplification of ITS2-DNAr together with HpaII enzyme restriction is an auxiliary molecular tool for the morphological identification of such snails as well as for taxonomic and phylogenetic studies of neotropical planorbids.

Molecular identification of similar species of the genus Biomphalaria (Mollusca: Planorbidae) determined by a polymerase chain reaction-restriction fragment length polymorphism

The freshwater snails Biomphalaria straminea, B. intermedia, B. kuhniana and B. peregrina, are morphologically similar; based on this similarity the first three species were therefore grouped in the complex B. straminea. The morphological identification of these species is based on characters such as vaginal wrinkling, relation between prepuce: penial sheath:deferens vas and number of muscle layers in the penis wall. In this study the polymerase chain reaction restriction fragment length polymorphism technique was used for molecular identification of these molluscs. This technique is based on the amplification of the internal transcribed spacer regions ITS1 e ITS2 of the ribosomal RNA gene and subsequent digestion of these fragments by restriction enzymes. Six enzymes were tested: Dde I, Mnl I, Hae III, Rsa I, Hpa II e Alu I. The restriction patterns obtained with DdeI presented the best profile for separation of the four species of Biomphalaria. The profiles obtained with all the enzymes were used to estimate the genetic distances among the species through analysis of common banding patterns.

Identification of planorbids from Venezuela by polymerase chain reaction amplification and restriction fragment length polymorphism of internal transcriber spacer of the RNA ribosomal gene

Snails of the genus Biomphalaria from Venezuela were subjected to morphological assessment as well as polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis. Morphological identification was carried out by comparison of characters of the shell and the male and female reproductive apparatus. The PCR-RFLP involved amplification of the internal spacer region ITS1 and ITS2 of the RNA ribosomal gene and subsequent digestion of this fragment by the restriction enzymes DdeI, MnlI, HaeIII and MspI. The planorbids were compared with snails of the same species and others reported from Venezuela and present in Brazil, Cuba and Mexico. All the enzymes showed a specific profile for each species, that of DdeI being the clearest. The snails were identified as B. glabrata, B. prona and B. kuhniana.

Identification of Biomphalaria havanensis and Biomphalaria obstructa populations from Cuba using polymerase chain reaction and restriction fragment length polymorphism of the ribosomal RNA intergenic spacer

In Cuba, several Biomphalaria species have been reported such as B. orbignyi, B. schrammi, B. helophila, B. havanensis and B. peregrina; only the latter three are considered as potential hosts of Schistosoma mansoni. The specific identification of Biomphalaria species is based on anatomical and morphological characters of genital organs and shells. The correct identification of these snails is complicated by the high variation in these characters, similarity among species and in some cases by the small size of the snails. In this paper, we reported the classical morphological identification, the use of PCR and RFLP analysis of the internal transcribed spacer region of the ribosomal RNA genes for molecular identification of seven snail populations from different localities in Cuba. Using morphological and molecular analysis, we showed that among the studied Cuban Biomphalaria populations only B. havanensis and B. obstructa species were found.

Mycobacterium bovis: polymerase chain reaction identification in bovine Lymphonode biopsies and genotyping in isolates from Southeast Brazil by spolygotyping and restriction fragment length polymorphism

Diagnosis of the Mycobacterium tuberculosis complex by direct PCR of mediastinal lymphnode DNA and microbiological tests were compared in cattle suspicious of bearing tuberculous-like lesions detected during slaughter. The PCR procedure applied on DNA samples (n=54) obtained by adding alpha -casein into the thiocyanate extraction mix was positive in 70% of the samples. PCR confirmed the identification of 23 samples (100%) that grew in culture, 9 samples (60%) that failed to grow in culture, plus 6 (37.5%) samples that resulted in growth of bacterial contaminants. Genotyping by IS6110-RFLP and DR-spoligotyping analysis of seven samples revealed the presence of several polimorphisms. Seven of the isolates contained multiple copies of IS6110, thus defining the existence of five singular genotypes.

Polymerase chain reaction and restriction fragment length polymorphism of cytocrome oxidase subunit I used for differentiation of Brazilian Biomphalaria species intermediate host of Schistosoma mansoni

The intermediate hosts of Schistosoma mansoni, in Brazil, Biomphalaria glabrata, B. tenagophila and B. straminea, were identified by restriction fragment length polymorphism analysis of the mitochondrial gene cytochrome oxidase I (COI). We performed digestions with two enzymes (AluI and RsaI), previously selected, based on sequences available in Genbank. The profiles obtained with RsaI showed to be the most informative once they were polymorphic patterns, corroborating with much morphological data. In addition, we performed COI digestion of B. straminea snails from Uruguay and Argentina.