The human neonatal small intestine has the potential for arginine synthesis; developmental changes in the expression of arginine-synthesizing and -catabolizing enzymes

Background  

Milk contains too little arginine for normal growth, but its precursors proline and glutamine are abundant; the small intestine of rodents and piglets produces arginine from proline during the suckling period; and parenterally fed premature human neonates frequently suffer from hypoargininemia. These findings raise the question whether the neonatal human small intestine also expresses the enzymes that enable the synthesis of arginine from proline and/or glutamine. Carbamoylphosphate synthetase (CPS), ornithine aminotransferase (OAT), argininosuccinate synthetase (ASS), arginase-1 (ARG1), arginase-2 (ARG2), and nitric-oxide synthase (NOS) were visualized by semiquantitative immunohistochemistry in 89 small-intestinal specimens.     

Fermentation characterization and flux analysis of recombinant strains of Clostridium acetobutylicum with an inactivated solR gene

The effect of solR inactivation on the metabolism of Clostridium acetobutylicum was examined using fermentation characterization and metabolic flux analysis. The solR-inactivated strain (SolRH) of this study had a higher rate of glucose utilization and produced higher solvent concentrations (by 25%, 14%, and 81%, respectively, for butanol, acetone, and ethanol) compared to the wild type. Strain SolRH(pTAAD), carrying a plasmid-encoded copy of the bifunctional alcohol/aldehyde dehydrogenase gene (aad) used in butanol production, produced even higher concentrations of solvents (by 21%, 45%, and 62%, respectively, for butanol, acetone, and ethanol) than strain SolRH. Clarithromycin used for strain SolRH maintenance during SolRH(pTAAD) fermentations did not alter product formation; however, tetracycline used for pTAAD maintenance resulted in 90% lower solvent production. Journal of Industrial Microbiology & Biotechnology (2001) 27, 322–328. Received 12 September 2000/ Accepted in revised form 21 July 2001     

Stimulation of allergen-loaded macrophages by TLR9-ligand potentiates IL-10-mediated suppression of allergic airway inflammation in mice

BackgroundPreviously, we demonstrated that OVA-loaded macrophages (OVA-Mφ) partially suppress OVA-induced airway manifestations of asthma in BALB/c mice. In vitro studies showed that OVA-Mφ start to produce IL-10 upon interaction with allergen-specific T cells, which might mediate their immunosuppressive effects. Herein, we examined whether IL-10 is essential for the immunosuppressive effects of OVA-Mφ in vivo, and whether ex vivo stimulation of the IL-10 production by OVA-Mφ could enhance these effects.MethodsPeritoneal Mφ were loaded with OVA and stimulated with LPS or immunostimulatory sequence oligodeoxynucleotide (ISS-ODN) in vitro. The increase of IL-10 production was examined and, subsequently, ex vivo stimulated OVA-Mφ were used to treat (i.v.) OVA-sensitized mice. To further explore whether Mφ-derived IL-10 mediates the immunosuppressive effects, Mφ isolated from IL-10^-/- mice were used for treatment.ResultsWe found that stimulation with LPS or ISS-ODN highly increased the IL-10 production by OVA-Mφ (2.5-fold and 4.5-fold increase, respectively). ISS-ODN stimulation of OVA-Mφ significantly potentiated the suppressive effects on allergic airway inflammation. Compared to sham-treatment, ISS-ODN-stimulated OVA-Mφ suppressed the airway eosinophilia by 85% (vs. 30% by unstimulated OVA-Mφ), IL-5 levels in bronchoalveolar lavage fluid by 80% (vs. 50%) and serum OVA-specific IgE levels by 60% (vs. 30%). Importantly, IL-10^-/-Mφ that were loaded with OVA and stimulated with ISS-ODN ex vivo, failed to suppress OVA-induced airway inflammation.ConclusionsThese results demonstrate that Mφ-derived IL-10 mediates anti-inflammatory responses in a mouse model of allergic asthma, which both can be potentiated by stimulation with ISS-ODN.     

Time-dependent thresholds for torpor initiation in the rufous hummingbird (Selasphorus rufus)

Summary Three models for torpor initiation were tested in rufous hummingbirds (Selasphorus rufus) during moult, when these birds appear to avoid the use of torpor. In model 1, the level of energy reserves at which torpor is initiated (the threshold) remains constant throughout the night. In model 2, the threshold declines throughout the night, at a constant rate equivalent to the rate at which energy reserves are depleted during torpor. In model 3, the threshold declines at a rate equivalent to the rate of energy reserve depletion during torpor for most of the night, but at a higher rate (corresponding to the rate of energy expenditure during normothermia) during the final 2 h of the night, when these birds are usually normothermic. Model 1 predicts the most frequent and longest bouts of torpor, whereas model 3 predicts the fewest and shortest bouts. To determine the thresholds for each of 12 birds, food supply was manipulated to induce entry into torpor at different times on successive nights. Threshold slopes matched the predictions of model 3 most closely. Calculations comparing observed incidence of torpor with the predictions of model 1 show that the actual, time-dependent threshold for torpor initiation resulted in a 72% reduction in the number of torpor bouts compared with the number of torpor bouts that should have been initiated by a constant threshold. The advantage of a time-dependent threshold is that, although torpor is initiated when needed to prevent energy reserves from falling below a critical level, the amount of time spent in torpor can be minimized. This may be especially important to rufous hummingbirds during the spring moult, because lowered metabolic rates during torpor probably result in decreased rates of feather replacement during the moult and may thus have consequences for thermoregulation, territorial defence, and timing of the spring migration.     

Identification and predicted sequence of a previously unrecognized small hydrophobic protein, SH, of the paramyxovirus simian virus 5.

A previously unrecognized gene (SH) has been identified on the virion RNA of the paramyxovirus simian virus 5 between the genes for the fusion protein and the hemagglutinin-neuraminidase. An SH mRNA of 292 nucleotides (plus polyadenylate residues), transcribed from the SH gene, has been identified. The SH mRNA contains a single open reading frame which encodes a polypeptide of 44 amino acids with a molecular weight of 5,012. The SH polypeptide is predicted to contain an extensive hydrophobic region. This protein has been identified in simian virus 5-infected cells, and it has been shown to be encoded by the SH mRNA by in vitro translation of size-fractionated mRNAs, hybrid-arrest translation, and hybrid-selection translation.     

Molecular characterisation of the caprine (<Emphasis Type="Italic">Capra hircus</Emphasis>) lymphocyte function-associated antigen-1 alpha subunit-encoding cDNA

Background

Lymphocyte function-associated antigen-1 (LFA-1, CD11a/CD18, alpha L beta 2) is required for many cellular adhesive interactions during the immune response.

Results

The Capra hircus CD11a-encoding cDNA was sequenced and compared with its human, murine, rat, bovine and ovine counterparts. Despite some focal differences, it shares all the main characteristics of its known mammalian homologues.

Conclusion

Therefore, along with the caprine CD18-encoding cDNA, which has been available for a few months, the sequence data revealed here will allow the Capra hircus LFA-1 expression in vitro as a tool to explore the specificities of inflammation in the caprine species.