Structural identification of novel oligosaccharides produced by Lactobacillus bulgaricus and Lactobacillus plantarum

β-Galactosidases (β-Gal) of lactic acid bacteria produce oligosaccharides from lactose when suitable acceptor carbohydrates are present. This study aimed to elucidate the structure of oligosaccharides formed by galactosylation of N-acetylglucosamine (GlcNAc) and fucose. Crude cellular extract of Lactobacillus bulgaricus and LacLM of Lactobacillus plantarum were used as sources of β-Gal activity. Disaccharides obtained by galactosylation of GlcNAc were identified as Gal-β-(1→4)-GlcNAc or Gal-β-(1→6)-GlcNAc by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and comparison with external standards. Trisaccharides were identified as Gal-β-(1→6)-Gal-β-(1→[4 or 6])-GlcNAc by LC-MS, analysis of the MS/MS spectra of selected in-source fragment ions, and their relative retention times. LC-MS analysis revealed the presence of five galactosylated fucosides, but their linkage type could not be identified, partly due to the lack of reference compounds. β-Gal of lactic acid bacteria may serve as suitable tools for the chemoenzymatic synthesis of therapeutic oligosaccharides.     

Preliminary studies on the insecticidal activity and wash-fastness of twelve pyrethroid treatments impregnated into bednetting assayed against mosquitoes

The insecticidal properties of twelve pyrethroid preparations impregnated into polyester netting were compared, before and after washing, with a view to assessing their suitability for treating bednets (mosquito nets) in the field. Bioassays were carried out by exposing the mosquitoes, Anopheles gambiae Giles sensu stricto andAedes aegypti L. to netting with two concentrations of insecticide, on washed and unwashed samples, for 30 s and 3 min at different times after impregnation. Mortality was recorded after 24 h. Permethrin applied at 97°C at pH 3.4 resulted in increased uptake by polyester fibres. The performance of most insecticides on unwashed netting had not declined appreciably 12 weeks after impregnation. However, all the insecticides were depleted by washing. The treatments with best insecticidal activity after washing were cypermethrin, lambda-cyhalothrin applied at ambient temperature and normal pH and permethrin applied in a hot acid solution.     

Evidence for chain molecules enriched in carbon, hydrogen, and oxygen in comet halley

In situ measurements of the composition and spatial distribution of heavy thermal positive ions in the coma of comet Halley were made with the heavy-ion analyzer RPA2-PICCA aboard the Giotto spacecraft. Above 50 atomic mass units an ordered series of mass peaks centered at 61, 75, 91, and 105 atomic mass units were observed. Each peak appears to be composed of three or more closely spaced masses. The abundances decrease and the dissociation rates increase smoothly with increasing mass. These observations suggest the presence of chain molecules that are enriched in carbon, oxygen, and hydrogen, such as polyoxymethylene (polymerized formaldehyde), in comet Halley.     

Animal well-being and animal care

To know how to care for animals, one must understand their needs. Physiologic and safety needs of farm animals are reasonably well fulfilled. Behavioral needs have yet to be determined and used as bases for animal care. The concept of the welfare plateau is important for the design and operation of facilities for agricultural animals. Current issues in the care of farm animals include standard agricultural practices, stockmanship and the human-animal bond, and standards of design for animal-production equipment.     

Physicochemical structure-activity relationship of DDT congeners and the inhibition of mitochondrial ATPase

Structure-activity relationships were used to determine the physicochemical properties of DDT that are important in the inhibition of oligomycin-sensitive mitochondrial ATPase activity of red coxal muscle tissue homogenates of the American cockroach (Periplaneta americana). The results were compared with structure-activity relationships derived from toxicity values for houseflies (Musca domestica) and blowflies (Phormia regina), reported in the literature. Toxicity was found to be promoted by hydrophobicity and electron donation. Toxicity was concluded to be a route of action process involving the distribution and partitioning of insecticide to active sites and apart from them. Enzyme inhibition, in contrast to factors contributing to toxicity, was determined to be a mode of action process predicted by the lipophilic parameter (π) and the steric constant, van der Waals radii (VWR), and represents action upon a sterically sensitive, hydrophobic site in the membrane sector of mitochondrial ATPase.     

Regulation of muscle differentiation: stimulation of myoblast fusion in vitro by catecholamines

Epinephrine and isoproterenol provoke primary chick myoblasts to initiate precocious cell fusion. Both the rise in intracellular adenosine 3' ,5-monophosphate (cyclic AMP) and cell fusion generated by these effectors are prevented by propranolol, which is a specific blocker of the beta-adrenergic receptor. Propranolol has no effect either on the precocious cell fusion provoked by prostaglandin E or on cell fusion in control cultures. The results support the idea that a rise in cyclic AMP is the critical intracellular change responsible for initiating events that culminate in myoblast differentiation 4 to 5 hours later. They also indicate that the culminate in myoblast differentiation 4 to 5 hours later. They also indicate that the hormone responsible for the positive regulation of myoblast differentiation in vitro is not acting through the beta-adrenergic receptor.