Chromosomal Location of a Gene Defining Nicotinamide Deamidase in Escherichia coli

A gene specifying the enzyme nicotinamide deamidase has been mapped, by the interrupted mating technique, at about 33 min on the chromosome of Escherichia coli K-12.     

Partial Characterization of C(x) Cellulase and Cellobiase from Ripening Tomato Fruits

Cellulolytic enzymes were studied in extracts from the locular contents of ripening fruits of Lycopersicon esculentum var. KC-146. When acting on carboxymethyl cellulose, the enzyme preparations were capable of decreasing the viscosity of the reaction mixture and generating reducing groups, oligosaccharides, and glucose. Cellobiose cellotriose, cellotetrose, and cellopentose also served as substrates for glucose production.     

CHEST INJURIES AMONG KOREAN CASUALTIES

Major wounds of the chest usually cause immediate or early death. Of 35 patients with major thoracic battle injuries who were treated in one naval hospital, six had non-penetrating wounds of the chest and other areas. Of the 29 with penetrating wounds of the chest, 23 were treated by aspiration of hemothorax, decortication in three cases, and thoracotomy for control of hemorrhage in one case and for removal of a foreign body in another.Four cases are reported, two to illustrate the usual course of treatment and two in which the patient died.     

THE FREE AMINO ACIDS OF HUMAN SPINAL FLUID DETERMINED BY ION EXCHANGE CHROMATOGRAPHY

(1) The free amino acids in human CSF from eighteen subjects have been determined. The analyses were performed on 0-75 ml of CSF by an ion exchange chromatographic method which is capable of detection to the 10^?10 mole level. (2) The amino acids always found in readily detectable amounts were: taurine, threonine, serine, glutamine, glutamic acid, citrulline, glycine, alanine, α-NH₂-n- butyric acid, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, ethanolamine, ornithine, lysine, histidine and arginine. Urea was present. Aspartic acid and cystine, though always present, occurred in small or trace amounts. Proline was found in four cases and tryptophan in thirteen cases. In addition, twelve unknown peaks were nearly always evident in every chromatogram. (3) Filtrates 10 times more concentrated than those used regularly were prepared from pooled CSF and analysed. These analyses clearly confirmed the presence of those amino acids which were normally in very low concentration and they also served to distinguish the twelve unknown compounds from confusion with baseline artifacts. (4) The distribution of free amino acids in CSF was different from their distribution in blood plasma. (5) Despite a variety of neurological conditions and a wide age span few marked deviations were found in any of the amino acid concentrations.     

Nematode sperm motility: nonpolar filament polymerization mediated by end-tracking motors

In nematode sperm cell motility, major sperm protein (MSP) filament assembly results in dynamic membrane protrusions in a manner that closely resembles actin-based motility in other eukaryotic cells. Paradoxically, whereas actin-based motility is driven by addition of ATP-bound actin subunits onto actin filament plus-ends located at the cell membrane, MSP dimers assemble from solution into nonpolar filaments that lack a nucleotide binding site. Thus, filament polarity and on-filament ATP hydrolysis, although essential for actin-based motility, appear to be unnecessary for membrane protrusions by MSP. As a potential resolution to this paradox, we propose a model for MSP filament assembly and force generation by MSP filament end-tracking proteins. In this model, ATP hydrolysis drives affinity-modulated, processive interactions between membrane-associated proteins and elongating filament ends. However, in contrast to the "actoclampin" model for actin filament end-tracking motors, ATP activates the tracking protein (or a soluble cofactor) rather than the MSP subunits themselves (in contrast to activation of actin subunits by ATP binding). The MSP end-tracking model predicts properties that are consistent with several key observations of MSP-based motility, including persistent membrane attachment, polymerization of filament ends at the membrane with depolymerization of free-filament ends away from the membrane, as well as a saturating dependence of polymerization rate on the concentration of non-MSP soluble cytoplasmic components.