Flies as a source of enteric pathogens in a rural village in Thailand.

The village of Ban Pong in northeastern Thailand was studied from January through December 1981 to determine the importance of flies as a source of enteric pathogens. The number of flies (predominantly Musca domestica) increased in kitchens and animal pens in the hot dry spring, when the incidence of diarrhea was highest in the village. Enterotoxigenic Escherichia coli, Shigella spp., non-O1 Vibrio cholerae, and Vibrio fluvalis were isolated from fly pools in yards (69%), animal pens (38%), bathrooms (35%), and kitchens (8%). Enterotoxigenic E. coli was isolated from one fly pool in May and from another in June, when the incidence of such infections was highest in the village. Flies often carry and presumably disseminate enteric pathogens in rural Thailand.     

Meningitis with Acinetobacter calcoaceticus in cerebrospinal fluid. A case report

A case of meningitis due to Acinetobacter calcoaceticus occurred after neurosurgery. The cerebrospinal fluid cytology showed intracellular diplococci that strongly resembled Neisseria meningitidis. However, subsequent bacteriologic studies revealed a bacterium identical to A. calcoaceticus. It is of practical importance for cytology laboratories to recognize this diplococcal form of organism.     

Structure of tomato busy stunt virus IV. The virus particle at 2.9 A resolution

The structure of tomato bushy stunt virus has been determined crystallographically to 2.9 A resolution. Details are presented of both the molecular structure and the methods by which it has been solved. The icosahedrally symmetric viral shell is composed of 180 protein subunits (Mr 43,000), with three similar but distinct modes of subunit bonding. This capacity for alternative packing is due to localized flexibility in the folded polypeptide (hinges between domains) and to multiple conformations for surface side-chains. The polypeptide backbone has an essentially invariant fold within a compact domain. A mechanism for correct positioning of the different modes of subunit interaction is evident from the structure of the TBSV particle. Thirty-five residues of the polypeptide chain fold in an ordered way on 60 of the 180 subunits, forming an internal framework. Interaction of folded domains with this framework permits accuracy of long-range geometry (correct curvature and closure) to be determined by unambiguous switching between alternative local contact angles. RNA packs tightly into the particle interior. Protein-RNA interactions occur through parts of the subunit that are flexibly linked to the well-ordered domains of the shell. This variable interaction imposes minimum restrictions on the folding of the RNA chain.     

Immunoreactive met-enkephalin in the canine adrenal; response to acute hypovolemic stress

Immunoreactive met-enkephalin was measured in the adrenal, kidney, liver, and intestine of the dog using radioimmunoassay. Adrenal tissue concentrations were 20 to 200-fold higher than the other tissues studied. In response to acute hypovolemic stress, the concentration of met-enkephalin in the adrenal vein of the dog increased 6-fold over basal peripheral arterial levels. These results suggest that the canine adrenal gland is a rich source of this opioid peptide and that the adrenal releases met-enkephalin in response to acute stress.     

Divalent cation sites in tomato bushy stunt virus. Difference maps at 2-9 A resolution

Difference electron density maps, using as few as four 1/2 degrees oscillation photographs, have been computed for tomato bushy stunt virus crystals soaked in EDTA. GdCl3 and silicotungstate. The maps define a double divalent cation site, responsible for regulating expansion of the virus particle, as well as sites for binding tungstate anions.     

Association of three highly mutable genes involving pigmentation in Anthirrhinum majus

Unstable alleles at three unlinked loci (delilah, nivea and pallida) can mutate somatically to allow the production of clones of pigmented cells (“flakes”) in particular parts of the corolla. The size of the flakes depends on the timing of the mutations during the development of the flower.     

Selective precipitation of ribonucleic acid from a mixture of total cellular nucleic acids extracted from cultured mammalian cells

A simple and reproducible method is described for precipitating RNA selectively from total mammalian-cell nucleic acids extracted by the phenol-sodium dodecyl sulphate procedure at pH8.0. Under specified conditions bulk RNA is precipitated almost quantitatively whereas bulk DNA remains in solution. Minor components of RNA (detected by pulse-labelling and chromatography on methylated albumin-kieselguhr) and rapidly labelled components of DNA containing single-stranded regions are also precipitated. The usefulness of the method is discussed in the context of isolating separately both RNA and DNA from cultured cells that are difficult to obtain in quantity.     

Salivary glands of the cat: A histochemical study

Synopsis The submandibular, sublingual and parotid glands of the cat have been studied. Mucosubstance histochemistry demonstrated acidic mucosubstances with varying properties in the acini. Thiamine pyrophosphatase and nucleoside diphosphatase reaction products were seen with a Golgi-like appearance in acinar cells. Granules of acid phosphatase, -glucuronidase and E600-resistant esterase reaction products, presumably representing lysosomal enzyme activities, were seen in acinar and ductal cells. Diffuse acid phosphatase and -glucuronidase reaction products were seen in central cells of the submandibular acini, and diffuse non-specific esterase reaction product was seen in acinar and ductal cells. Arylamidase reaction product was associated with some acinar cells. Reaction product from a peroxidase technique was seen in demilunar cells of the submandibular acini, in parts of the sublingual acini, in parotid acini, and in ductal cells. Cytochrome oxidase and succinate dehydrogenase reaction products were seen most strongly in striated ducts, whereas NADH- and NADPH-diaphorase reaction products were seen at a high level throughout the ducts.