Bioinformatic characterization of the extracellular lipases from Kluyveromyces marxianus

Lipases are hydrolytic enzymes that break the ester bonds of triglycerides, generating free fatty acids and glycerol. Extracellular lipase activity has been reported for the nonconventional yeast Kluyveromyces marxianus, grown in olive oil as a substrate, and the presence of at least eight putative lipases has been detected in its genome. However, to date, there is no experimental evidence on the physiological role of the putative lipases nor their structural and catalytic properties. In this study, a bioinformatic analysis of the genes of the putative lipases from K. marxianus L-2029 was performed, particularly identifying and characterizing the extracellular expected enzymes, due to their biotechnological relevance. The amino acid sequence of 10 putative lipases, obtained by in silico translation, ranged between 389 and 773 amino acids. Two of the analysed putative proteins showed a signal peptide, 25 and 33 amino acids long for KmYJR107Wp and KmLIP3p, and a molecular weight of 44.53 and 58.23 kDa, respectively. The amino acid alignment of KmLIP3p and KmYJR107Wp with the crystallized lipases from a patatin and the YlLip2 lipase from Yarrowia lipolytica, respectively, revealed the presence of the hydrolase characteristic motifs. From the 3D models of putative extracellular K. marxianus L-2029 lipases, the conserved pentapeptide of each was determined, being GTSMG for KmLIP3p and GHSLG for KmYJR107Wp; besides, the genes of these two enzymes (LIP3 and YJR107W) are apparently regulated by oleate response elements. The phylogenetic analysis of all K. marxianus lipases revealed evolutionary affinities with lipases from abH15.03, abH23.01, and abH23.02 families.     

Synthesis of N,N-diethyl-N-{4-[(E)-(4-nitrophenyl)diazenyl]phenyl}amine via in situ diazotisation and coupling in supercritical carbon dioxide

The synthesis of azo dyes via a conventional aqueous-based diazotisation and coupling reaction requires the use of relatively high concentrations of mineral acids, which leads to high electrolyte concentrations in wastewater. Reported in this paper is an environmentally benign one-pot method for the synthesis of a nonionic azo dye, N,N -diethyl- N -{4-[( E )-(4-nitrophenyl)diazenyl]phenyl}amine, in supercritical carbon dioxide without using a mineral acid. The product yield increased significantly with temperature, with 91% theoretical yield afforded at 80 °C. The pressure of the system had little influence on product yield.     

Comparison of Etest to broth microdilution method for testing Streptococcus pneumoniae susceptibility to levofloxacin and three macrolides

When the Etest was compared to broth microdilution for susceptibility testing of Streptococcus pneumoniae, levofloxacin, erythromycin, and penicillin results correlated for both methods; azithromycin and clarithromycin showed discrepancies of > or = 2 dilutions for 95.8% and 31.5% of the isolates, respectively. Levofloxacin was active against 141 of 142 isolates (< or = 2.0 micrograms/ml), making it a potentially useful new fluoroquinolone.     

Self-organizing maps as a model of brain mechanisms potentially linked to autism.

The application of artificial neural networks in the study of psychopathological syndromes has great potential. Several computational models of acquired and developmental disorders, including autism, have been proposed recently. In this paper, we use the framework of self-organizing maps to study several aspects of autism, by modeling abnormalities in the learning process in biologically plausible manners. We then interpret the resulting feature maps with reference to autistic characteristics. The effects of manipulating the physical structure and size of self-organizing maps were measured and compared with the general characteristics of neural growth abnormalities in autistic children. We find no effect on stimuli coverage, but a negative impact on map unfolding, dependant on the intensity of the abnormality, but not the time of onset. We analyze sensory issues by introducing the concept of attention functions, used to model hypersensitivities and hyposensitivities. The issue of focus on details rather than the whole is analyzed through a model in which distant neighbors are explicitly rejected; we show the model may lead to improved coverage of finely-shaped areas or isolated stimuli, but poorer map unfolding. Finally, we consider effects of noisy communication channels on the development of maps, and show a strong sensitivity of both coverage and unfolding of maps.     

Modeling the Combining Site of the Human Asialoglycoprotein Receptor

A model for the carbohydrate recognition domain (CRD) and combining site of the human asialoglycoprotein (ASGP) receptor has been computed on the basis of the close sequence homology with the mannose-binding lectin (MBP), whose three-dimensional structure in complex with a ligand has been determined by crystallographic methods (Weis, W.I.; Drickamer, K.; Hendrickson, W.A. Nature 1992, 360: 127). Within the limitations of modeling methods, the model is compatible with data on ligand binding of the family C-type lectins, of which the MBP and the ASGP receptor are members. The model derived can serve as a guide for designing site-directed mutagenesis experiments in order to further elucidate the origins of specificity of the ASGP receptor toward galactose. In particular, the model focuses attention on the possible role of position 207 (MBP sequence numbering) in promoting galactose binding.     

An expert PID controller uses refined ziegler and nichols rules and fuzzy logic ideas

This article proposes a scheme for the on-line adjustment of three mode controller settings based on experimental measurements of closed-loop performance. It uses a recently developed heuristic tuning procedure to identify estimated process parameters. This method may give rise to conflicting estimates. Fuzzy Set theory is applied to manage the situation in terms of a fuzzy conjunction to combine the various estimates. PID control was chosen because of its wide use in the industrial environment due to driving simplicity and robustness. The article shows design, development, and computer simulation aspects.     

Effect of breed-type on the relationships between intramuscular and total body fat in steers

The partitioning of total dissectible body fat and the amounts of intramuscular fat in Psoas major, Semitendinosus and Biceps brachii muscles were determined in two groups of A. Angus and AA × Nelore steers with similar averages of total dissectible fat (27·7 kg). In addition, the fatty acid composition of total fat and the triglyceride fraction from dissectible and intramuscular fats were determined.

The AA × Nelore steers have higher levels of subcutaneous fat and lower levels of intermuscular fat than the A. Angus but contain lower levels of intramuscular fat in the three muscles. The allometric regressions varied according to the muscle and breed type. The fatty acid composition of subcutaneous and kidney fats were similar but differences in the percentages of 14:0, 18:0, 18:2 and 20:4 fatty acids in intramuscular fats between the two genetic groups were detected.     

A comparison of distribution and composition of intramuscular fat in Duroc Jersey and Hampshire pigs at 100 kg liveweight

The intramuscular fat content, its fatty acid composition and that from the triglyceride fraction, were determined in several muscles from the right sides of four Duroc Jersey and four Hampshire castrated male pigs slaughtered at 100 kg liveweight. The Hampshires had heavier muscles than the Duroc Jersey pigs, but did not show significant differences in the percentages of intramuscular fat. The concentrations of linoleic acid were, in general, higher in the Hampshire than in the Duroc Jersey pigs and in many muscles the differences were highly significant (p < 0·05) The concentrations of linoleic acid (18:2) in the triglyceride fraction did not differ among muscles within breeds but were higher in Hampshire than in Duroc Jersey pigs.