The fatty acid composition of muscle and adipose tissues from entire and castrated male Boer goats raised in Australia

The fatty acid composition of longissimus thoracis (LT) muscle and adipose tissues (subcutaneous and intermuscular fat) from castrated and entire male Boer goat bucks was investigated. Sixty Boer bucks in groups of between three and five animals were slaughtered at 5, 15, 30, 45, 60, 75, 90 and 105 kg live weight (5 and 15 kg animals were not castrated). The fatty acid composition of LT muscle from castrated and entire Boers was significantly affected by slaughter weight. The fatty acid content of LT muscle and subcutaneous and intermuscular fat from both castrated and entire Boer bucks was primarily composed of oleic acid followed by palmitic and stearic acid. Both oleic and palmitic acid increased with slaughter weight whereas stearic acid decreased. LT muscle from castrated Boer bucks contained higher amounts of desirable fatty acids. In contrast to slaughter weight, castration of Boer bucks resulted in only minor changes in fatty acid composition of adipose tissues. It can be concluded that slaughter weight plays a role in changing the fatty acid composition of LT muscle and adipose tissues from Boer bucks.

Direct fermentation of potato starch wastewater to lactic acid by Rhizopus oryzae and Rhizopus arrhizus

The biochemical kinetic of direct fermentation for lactic acid production by fungal species of Rhizopus arrhizus 3,6017 and Rhizopus oryzae 2,062 was studied with respect to growth pH, temperature and substrate. The direct fermentation was characterized by starch hydrolysis, accumulation of reducing sugar, and production of lactic acid and fungal biomass. Starch hydrolysis, reducing sugar accumulation, biomass formation and lactic acid production were affected with the variations in pH, temperature, and starch source and concentration. A growth condition with starch concentration approximately 20 g/l at pH 6.0 and 30 degrees C was favourable for both starch saccharification and lactic acid fermentation, resulting in lactic acid yield of 0.87-0.97 g/g starch associated with 1.5-2.0 g/l fungal biomass produced in 36 h fermentation. R. arrhizus 3,6017 had a higher capacity to produce lactic acid, while R. oryzae 2,062 produced more fungal biomass under similar conditions.

Simultaneous saccharification and fermentation of potato starch wastewater to lactic acid by Rhizopus oryzae and Rhizopus arrhizus

The biochemical kinetic of simultaneous saccharification and fermentation (SSF) for lactic acid production by fungal species of Rhizopus arrhizus 36017 and Rhizopus oryzae 2062 was studied with respect to growth pH, temperature and substrate. Both R. arrhizus 36017 and R. oryzae 2062 had a capacity to carry out a single stage SSF process for lactic acid production from potato starch wastewater. The kinetic characteristics, termed as starch hydrolysis, accumulation of reducing sugars, lactic acid production and fungal biomass formation, were affected with variations in pH, temperature, and starch source and concentration. A growth condition with starch concentration approximately 20 g/l at pH 6.0 and 30 degrees C was favourable for both starch saccharification and lactic acid fermentation, resulting in lactic acid yield of 0.85-0.92 g/g associated with 1.5-3.5 g/l fungal biomass produced in 36-48 h fermentation. R. arrhizus 36017 had a higher capacity to produce lactic acid, while R. oryzae 2062 produced more fungal biomass under similar conditions. (c) 2005 Elsevier B.V. All rights reserved.

The crystal structure of a bacterial Class II ketol-acid reductolsomerase: Domain conservation and evolution

Ketol-acid reductoisomerase (KARI; EC 1.1.1.86) catalyzes two steps in the biosynthesis of branched-chain amino acids. Amino acid sequence comparisons across species reveal that there are two types of this enzyme: a short form (Class 1) found in fungi and most bacteria, and a long form (Class 11) typical of plants. Crystal structures of each have been reported previously. However, some bacteria such as Escherichia coli possess a long form, where the amino acid sequence differs appreciably from that found in plants. Here, we report the crystal structure of the E. coli enzyme at 2.6 A resolution, the first three-dimensional structure of any bacterial Class 11 KARI. The enzyme consists of two domains, one with mixed alpha/beta structure, which is similar to that found in other pyridine nucleotide-dependent dehydrogenases. The second domain is mainly alpha-helical and shows strong evidence of internal duplication. Comparison of the active sites between KARI of E. coli, Pseudomonas aeruginosa, and spinach shows that most residues occupy conserved positions in the active site. E. coli KARI was crystallized as a tetramer, the likely biologically active unit. This contrasts with P. aeruginosa KARI, which forms a dodecamer, and spinach KARI, a dimer. In the E. coli KARI tetramer, a novel subunit-to-subunit interacting surface is formed by a symmetrical pair of bulbous protrusions.

The influence of architecture on degradation and tissue ingrowth into three-dimensional poly(lactic-co-glycolic acid) scaffolds in vitro and in vivo

The in vitro and in vivo degradation properties of poly(lactic-co-glycolic acid) (PLGA) scaffolds produced by two different technologies-therm ally induced phase separation (TIPS), and solvent casting and particulate leaching (SCPL) were compared. Over 6 weeks, in vitro degradation produced changes in SCPL scaffold dimension, mass, internal architecture and mechanical properties. TIPS scaffolds produced far less changes in these parameters providing significant advantages over SCPL. In vivo results were based on a microsurgically created arteriovenous (AV) loop sandwiched between two TIPS scaffolds placed in a polycarbonate chamber under rat groin skin. Histologically, a predominant foreign body giant cell response and reduced vascularity was evident in tissue ingrowth between 2 and 8 weeks in TIPS scaffolds. Tissue death occurred at 8 weeks in the smallest pores. Morphometric comparison of TIPS and SCPL scaffolds indicated slightly better tissue ingrowth but greater loss of scaffold structure in SCPL scaffolds. Although advantageous in vitro, large surface area:volume ratios and varying pore sizes in PLGA TIPS scaffolds mean that effective in vivo (AV loop) utilization will only be achieved if the foreign body response can be significantly reduced so as to allow successful vascularisation, and hence sustained tissue growth, in pores less than 300 mu m. (C) 2005 Elsevier Ltd. All rights reserved.

Macrophage-specific expression of human lysosomal acid lipase corrects inflammation and pathogenic phenotypes in lal(-/-) mice

Lysosomal acid lipase (LAL) hydrolyzes cholesteryl esters and triglycerides to generate free fatty acids and cholesterol in the cell. The downstream metabolites of these compounds serve as hormonal ligands for nuclear receptors and transcription factors. Genetic ablation of the lal gene in the mouse caused malformation of macrophages and inflammation-triggered multiple pathogenic phenotypes in multiple organs. To assess the relationship between macro phages and lal(-/-) pathogenic phenotypes, a macrophage-specific doxycycline-inducible transgenic system was generated to induce human LAL (hLAL) expression in the lal(-/-) genetic background under control of the 7.2-kb c-fins promoter/intron2 regulatory sequence. Doxycycline-induced hLAL expression in macrophages significantly ameliorated aberrant gene expression, inflammatory cell (neutrophil) influx, and pathogenesis in multiple organs. These studies strongly support that neutral lipid metabolism in macrophages contributes to organ inflammation and pathogenesis.