Comparative Studies on Generalized Transducing Bacteriophages of Proteus mirabilis, φm and π1

Comparative studies were made on the generalized transducing bacteriophages of Proteus mirabilis φm (Nakaya and Rownd), π1 (Böhme), and a clear plaque-forming mutant φm-c, derived from φm. Electron microscopic observations revealed that these phages were morphologically identical, indicating that they belonged to the group C of Bradley's classification, or to the type Cl of Ackermann's classification. Phages φm and π1 formed characteristic turbid plaques different from each other, and the plaques of π1 were smaller in size than those of φm. The plaques of phage φm-c were clear and also were the largest in size among those studied. Average latent periods of φm and π1 were 70 and 60 min, respectively. Average burst size was found to be 30 and 10 plaque-forming units per infected cell for φm and π1, respectively. It was confirmed by cross neutralization tests that φm and π1 differed serologically from each other. The host range of the two phages also differed, and phage φm was more sensitive to heat than π1. These results indicate that phages φm and π1 are different types of phages. Majority of the properties of phage φm-c were nearly identical with those of phage π1 except that the multiplication of φm-c was more strongly inhibited by methylene blue than that of φm and π1. Phage φm-c is considered to be a clear mutant of φm.     

Hydrophobic Core Formation and Dehydration in Protein Folding Studied by Generalized-Ensemble Simulations

Despite its small size, chicken villin headpiece subdomain HP36 folds into the native structure with a stable hydrophobic core within several microseconds. How such a small protein keeps up its conformational stability and fast folding in solution is an important issue for understanding molecular mechanisms of protein folding. In this study, we performed multicanonical replica-exchange simulations of HP36 in explicit water, starting from a fully extended conformation. We observed at least five events of HP36 folding into nativelike conformations. The smallest backbone root mean-square deviation from the crystal structure was 1.1 Å. In the nativelike conformations, the stably formed hydrophobic core was fully dehydrated. Statistical analyses of the simulation trajectories show the following sequential events in folding of HP36: 1), Helix 3 is formed at the earliest stage; 2), the backbone and the side chains near the loop between Helices 2 and 3 take nativelike conformations; and 3), the side-chain packing at the hydrophobic core and the dehydration of the core side chains take place simultaneously at the later stage of folding. This sequence suggests that the initial folding nucleus is not necessarily the same as the hydrophobic core, consistent with a recent experimental ϕ-value analysis.     

A possible relationship between cord blood transferrin and birth length in infants

Cord blood levels of transferrin (Tf) and insulin-like growth factor I (IGF-1) were measured in 33 normal and 12 preterm infants. Tf was measured by the single radial immunodiffusion technique, while IGF-1 was measured by specific RIA. Tf levels in normal term infants (195 +/- 27 mg/dl) were significantly below normal adult levels (261 +/- 12 mg/dl). Tf levels in preterm infants (159 +/- 30 mg/dl) were lower than those in normal term infants. Tf levels showed a positive correlation with birth length, weight, gestational age and albumin levels in all infants. There was no correlation between Tf and IGF-1 levels in term and preterm infants.     

Production of chitinase and β-N-acetylglucosaminidase by intestinal bacteria of Pinnipedian animals

The chitinase- and β-N-acetylglucosaminidase(GlcNAcase)-producing ability of intestinal bacteria from Pinnipedian animals was determined using fluorogenic 4-methylumbelliferone glycosides of N-acetylglucosamine oligosaccharides. Intestinal microflora of a single Cape fur seal, three California sea lions and three South American sea lions were characterized by a predominance of isolates of the Bacteroidaceae and Enterobacteriaceae families and the genus Clostridium . Of the 711 isolates tested 26.0, 10.0 and 8.7% could hydrolyse 4-MU(GlcNAc)₁ 4-MU(GlcNAc)₂, and 4-MU(GlcNAc)₃, respectively. This result suggests that β-GlcNAcase producers occur at a higher density than do chitinase producers. Moreover, β-GlcNAcase, and to a lesser degree, chitinase seem to be efficiently produced by facultative anaerobes in the Cape fur seal and the California sea lion, and by both facultative and obligate anaerobes in the South American sea lion. To our knowledge, this is the first paper to report that isolates of the family Bacteroidaceae and the genus Streptococcus produce chitinase and/or β-GlcNAcase.     

Biological properties of plaque-size variants of Sendai virus

Large (RL)-and small (RS)-plaque variants of Sendai virus were isolated in culture of LLCMK2 cells in the presence of trypsin and their biological properties were determined. The RL variant was more virulent to mice than the RS variant. The RL variant had a higher growth rate than the RS variant in multiple-step growth in the presence of trypsin, but the two variants had an almost equal growth rate in its absence. Restoration of hemolytic activity in cleavage of the F protein of the RL variant were achieved by milder trypsin treatment than was needed for the RS variant.     

Innervation of dog ciliary ganglion

There are species differences with regard to the composition of the ciliary ganglion. For instance, in rabbits and cats it consists solely of oculomotor nerves and has no sympathetic or sensory innervation. The purpose of this study is to clarify the participation of these nerves in the ciliary ganglion of the dog by histochemical methods. Cholinesterase (ChE) activity was studied by Karnovsky's method and catecholamine fluorescence by the glyoxylic acid method. Furthermore, the origins of the respective nerves were investigated by a serial preparation method, involving unilateral cervical sympathectomy and tracer dye injection in the ganglion. The results obtained were: (1) Ciliary ganglion cells showed intense ChE activity. Oculomotor nerve fibers leading to the ganglion showed moderate ChE activity, while the reaction in the short ciliary nerves was strong. (2) Aminergic nerves were present in the intercellular space of the ciliary ganglion, and bilateral or central innervation was suggested by the results of cervical sympathectomy. (3) Connection between the ciliary and trigeminal ganglia was proved by the dye tracer study. The results show that the ciliary ganglion in dogs is composed of oculomotor, trigeminal and sympathetic nerves.