Spore-spheroplast transformation of Bacillus megaterium

A new method for transformation of Bacillus megaterium was developed by modification of Chang and Cohen's method. In our method, spore spheroplasts were used as recipient cells instead of the protoplasts of vegetative cells. Longer incubation (60 min) of spore spheroplasts and plasmid DNA before treatment with polyethylene glycol remarkably increased the efficiency of transformation. The frequency of transformation was about 10(4) per microgram of plasmid DNA. A shot-gun-type cloning of chromosome DNA of B. megaterium ATCC 12872 was available in B. megaterium ATCC 19213 strain by this transformation method.     

Pathogenicity for several laboratory animals of toxoplasma oocysts originated from naturally infected cats.

The pathogenicity of four strains, O-1, O-2, O-3, and O-4, of Toxoplasma isolated in the form of oocyst from the feces of naturally infected cats was examined for such laboratory animals as mice, rats, rabbits, guinea pigs, and dogs, in comparison with that of the Beverley strain. Suspensions of seven graded doses of oocysts of each strain ranging from 1.0 X 10(-1) to 1.0 X 10(5) were inoculated orally into seven groups of five mice each. The O-1, O-2, and O-3 strains were as pathogenic for mice as the Beverley strain, but the O-4 strain was not so pathogenic as any other strain. Rats, rabbits, guinea pigs, and dogs were inoculated orally with around 1.0 X 10(5) oocysts. The four O strains were not so severly pathogenic for rats and rabbits as to cause death. The O-2 and O-3 strains showed strong pathogenicity for guinea pigs, almost all of which, when inoculated with them, died after manifesting severe clinical symptoms. The pathogenicity of the O-1 and O-2 strains showed essentially the same tendency for dogs as for any other animal. In inoculation with oocysts, as well as with proliferative forms or cysts, the same pathogenicity was not observed in different strains, even if the same species of host animals was used. On the contrary, the same pathogenicity was not always found even in one strain when a different species of animals was used.     

Serologic differences in strains of Sporothrix schenckii.

To obtain evidence that Sporothrix scheneckii enters the body by contact with contaminated materials, the antigenic property of strains from different sources was investigated. The reciprocal absorption test of the antisera against a soil isolate and a human isolate (KO 4606) showed that the absorbed antisera against KO 4606 possessed unique antigen(s) in addition to the common antigen of both strains. Twenty-three clinical isolates were tested with absorbed antisera. Not all of them possessed the unique antigen(s), but there were serologic varieties among S. schenckii strains, regardless of their sources, clinical type of the disease and the morphology of the yeast phase cells.     

Effects of thiamine and pyridoxine on the content and composition of sterols in Saccharomyces carlsbergensis 4228

The level of sterols in $\text{S. carlsbergensis}$ 4228 cells grown aerobically on a synthetic medium fortified with thiamine was significantly low compared with that in the control cells. The levels of free and esterified sterols in the thiamine-cells were 60% and 10% of the corresponding sterol levels in the control cells, respectively. Analysis by gas-liquid chromatography of non-saponifiable lipids extracted from the cells revealed that the amounts of squalene, lanosterol and two unidentified sterols were higher than those in the control cells and that ergosterol and zymosterol, major sterols in the control cells, were not present. These effects of thiamine on the content and composition of sterols were abolished by the addition of pyridoxine to the medium.     

Identification of Candida isolated from the cutaneous candidiasis by the combined use of confirmatory medium and slide agglutination with monofactorial antibodies

Forty strains ofCandida and one ofTorulopsis were isolated from patients with cutaneous candidiasis. The isolates comprised 29 strains ofC. albicans, 7 strains ofC. tropicalis, 2 strains ofC. guilliermondii, and one each ofC. parakrusei, C. lipolytica, andT. famata were identified by the ordinary method. Besides the common pathogenC. albicans, a few other species ofCandida may be etiologic organisms of cutaneous candidiasis. These strains were re-examined by combined use of sucrose agar slants and slide agglutination tests with IgG monofactorial antibodies as a rapid identification method, especially for determining serotypes ofC. albicans. The new method was useful and reliable for rapid identification ofC. albicans and related species. All strains ofC. albicans isolated from skin lesions proved to be standard serotypes ofC. albicans.

---

Zusammenfassung Vierzig Stämme vonCandida und eins vonTorulopsis wurden aus Kranken mit kutanen Candidamykosen isoliert. Neunundzwanzig Stämme vonC. albicans, 7 vonC. tropicalis, 2 vonC. guilliermondii, und je einer vonC. parakrusei, C. lipolytica undT. famata wurden mit dem ordinären Methode identifiziert. Außer dem gewohnlichen Erreger,C. albicans, konnten auch ein Paar andere Spezies vonCandida als den Erreger betrachtet werden. Sechsunddreißig Stämme vonC. albicans undC. tropicalis wurden mit der von uns verbesserten kombinierten serologischen und biologischen Methode untersucht, besonders um den Serotypus vonC. albicans festzusetzen. Die neue Methode war gut und zuverlässig als die rapide Identification vonC. albicans und verwandten Spezies. Alle aus der Hautläsion isoliertenC. albicans waren der in Japan allgemeine Serotypus vonC. albicans.

     

Regulation of polar surface structures in Caulobacter crescentus: Pleiotropic mutations affect the coordinate morphogenesis of flagella, pili and phage receptors

Summary A large number of Caulobacter mutants resistant to DNA or RNA phages were isolated. These phage-resistant mutants exhibited phenotypic variations with respect to cell motility and sensitivity to other phages.The majority of the mutants was resistant to both DNA and RNA phages tested. In addition, these mutants were either motile or non-motile. The analysis of spontaneous revertants from these mutants indicated that a single mutation is involved in these phenotypic variations. Other mutants were resistant to RNA phages and only to a certain DNA phage tested, and were also motile or non-motile.Several temperature-sensitive phage-resistant mutants were also isolated. One of them, CB13 ple-801, exhibited the wild type phenotype when grown at 25°C. However, at a higher temperature (35°C), the mutant cells became non-motile and resistant to both DNA and RNA phages. These phenotypes seem to be attributed to the concommitant loss of flagella, pili and phage receptors. In other respects (cell growth and morphology, and asymmetric stalk formation), CB13 ple-801 was normal at 35°C. The spontaneous revertants from CB13 ple-801 simultaneously regained the wild type phenotypes in all respects.It is suggested that a single mutation pleiotropically affects the formation of flagella, pili and phage receptors.     

Assembly mechanism of tobacco mosaic virus particle from its ribonucleic acid and protein

Summary The reconstitution process of an infectious tobacco mosaic virus particle from its RNA and protein consists of two steps, formation of the initial complex and growth of the helical rod, the former is the rate limiting step. The protein aggregate, having about 20–30 S, is needed for the formation of the initial complex with 5-end of tobacco mosaic virus RNA. The elongation reaction from the initial complex proceeds even under conditions where both the reconstitution reaction and the formation of 20–30 S protein aggregates do not take place. This indicates that the growth of the helical rod proceeds by stepwise additions of protein subunits or 4 S aggregates. A possible model for assembly process of tobacco mosaic virus particle is presented.     

A new diabetic strain of rat (WBN/Kob)

A new, spontaneously occurring diabetic syndrome has been observed in the aged males of an inbred strain of Wistar rats, WBN/Kob. The main clinical sign, glycosuria, was first detected at about 60 weeks of age, and thereafter some animals developed hyperlipidaemia and gradual emaciation. Prior to the onset of glucosuria, male rats showed impaired glucose tolerance after a glucose load at 21 weeks of age. The histopathologic lesions of the pancreas in the diabetic males consisted of multifocal fibrosis, decreased in number and size of islets and atrophy of exocrine tissue. Multifocal inflammatory foci of varying stages were the main pancreatic lesion in prediabetic male rats. This inflammatory change was detected even in 12-week-old rats and tended to occur around the islets. Therefore focal fibrosis and the decrease in the number and size of islets were considered to result from post-inflammatory scarring. The maturity-onset of this syndrome and the impaired glucose tolerance in younger animals suggested that diabetes mellitus of this rat strain is insulin-independent type II. However, the histological lesions of the pancreas were somewhat different from previous reports of both type I and II diabetes mellitus in man and animals.     

Comparison of amino acid sequences between phosphoenolpyruvate carboxylases from Escherichia coli (allosteric) and Anacystis nidulans (non-allosteric): identification of conserved and variable regions

Amino acid sequences of phosphoenolpyruvate carboxylases of Escherichia coli (allosteric) and a cyanobacterium Anacystis nidulans (non-allosteric) were aligned. The pattern of homology suggests that the enzyme molecule is comprised of two distinct regions, namely, a conserved region (C-terminal half) and a variable region (N-terminal half). Among the amino acid residues which have previously been presumed essential for the catalytic activity, three histidine residues were found to be conserved, but cysteine residues were not. Furthermore, the conserved sequence unique to the enzyme was identified by comparison of the enzyme sequence with amino acid sequences in our data bank.