Biomedical subjects
Publications and source records attributed to S S Kasatiya.
Out of 136 new phages, 80 (59%) are classified into 23 species according to morphology and physicochemical properties. Six new species are described and species beta 4, from a previous classification scheme, is renamed T1. The morphology of 36 phage species is schematically represented.
Bacillus cereus is responsible for an increasing number of food poisoning cases. By using 12 bacteriophages isolated from sewage, a typing scheme for B. cereus isolates from outbreaks or sporadic cases of food poisoning was developed. The phages belonged to three morphotypes. Ten phages with contractile tails and icosahedral heads were members of the Myoviridae family, and two phages with noncontractile tails belonged to the Siphoviridae family. Phage 11 represented a new species. It had an isometric head and a very long contractile tail with long wavy tail fibers and was one of the largest viruses known. The vast majority of 166 B. cereus strains (161, or 97%) isolated from food poisoning cases were typeable. Of 146 strains isolated from 18 outbreaks, 142 (97%) could be divided into 17 phage types. A good correlation, on the order of 80 to 100%, between phage types of strains isolated from suspected foods and those of strains isolated from stools of symptomatic patients was observed. Most Bacillus thuringiensis strains were also typeable, providing further evidence of the close relatedness of B. cereus and B. thuringiensis. This phage typing scheme can be a valuable epidemiological tool in tracing the origins of food poisoning caused by B. cereus.
Two hybridoma cell lines producing monoclonal antibodies (MAbs) to mycoplasmas were established by fusion of mouse myeloma and spleen cells obtained from mice immunized with whole cell Mycoplasma pneumoniae antigens. The MAbs designated as MYC-4 and MYC-9 bound to a single M. pneumoniae protein band with approximate molecular weights of 150,000. In dot-EIA both MAbs reacted with ten Mycoplasma spp., two serovars of Ureaplasma urealyticum and Acholeplasma laidlawii. The MAbs have great potential to be used as an antibody probe for the rapid screening of cell cultures and hybridomas for mycoplasmal contamination.
A nosocomial outbreak of dermatophytosis caused by Trichophyton tonsurans var. sulfureum subvar. perforans is reported in a nursing home for the elderly. The outbreak affected six residents and persisted for nine months despite remedial medical and sanitary measures. In a survey designed to determine the potential role of fomites in disease transmission, 129 environmental sites were sampled. A high proportion (22.3%) of the samples yielded T. tonsurans, including samples from beds, floors, and washroom facilities. Methods for the control of dermatophyte outbreaks in chronic care institutions are discussed.
85 Vibrio phages, 84 of them tailed and 1 filamentous, were surveyed. The tailed phages belonged to six basic morphotypes and to the Myoviridae, Siphoviridae, or Podoviridae families. 63 phages were classified into 18 species. The filamentous phage is a member of the Inovirus genus of the Inoviridae family. Vibrio phages are very heterogenous and include some morphologically interesting viruses. Several Vibrio phages closely resemble phages of other gram-negative bacteria, possibly indicating phylogenetic relationships between their hosts.
A new Salmonella serotype classified in the Kauffman sub-genus I (Kauffman 1963) has been isolated in Canada from a stock of cacao beans from Nigeria. Salmonella sherbrooke shares the antigenic structure 16:d:1,6.
Our experiments have shown that the cotton plug located at the top end of a "Pasteur pipette" allows aerosol to escape upon aspiration of a bacterial culture broth and may be the cause of contamination. In the following, we propose the use of a bacteriological filter system which insures greater safety.
The apparatus described in this article can distribute simultaneously 22 drops of different phage suspensions at a rate of 13,200 drops per hour, which is superior than the one obtained with the presently available apparatuses. It could eventually be attached to a Petri dish distributor.
Cytological effects were investigated in the Chinese hamster cell line (CHO-K1) exposed to microwave radiation of 2450 MHz frequency and incident power of 25 to 200 W for a period of 30 min. Nuclear vacuoles, pycnotic and decondensed chromosomes were observed in cells exposed to 25 W under elevated temperature conditions (uncontrolled temp). In addition a significant increase in chromosomal breakages/cell was observed. Cells exposed to relatively higher power, 75-200 W, under hypothermic conditions (29 degrees C) revealed no significant increase in either nuclear vacuoles or other chromosomal anomalies over control cells. Radiation-induced temperature elevation appears to be an essential factor in the cytological effects of microwave.
Six related Staphylococcus phages spontaneously produced various abnormal head and tail structures: (i) giant capsids which were tailed and apparently contained nucleic acid; (ii) regular and irregular smooth polyheads; (iii) heads and polyheads with wavy outlines; (iv) mottled heads and polyheads; (v) abnormally long and short tails; and (vi) "double capsids" connected by a small bridge. Some of these structures are rare, or have not yet been reported. The frequency os specific aberrant particles varied from one phage to another. Length distribution of smooth irregular polyheads and of abnormal tails indicated that these structures assemble at random from protein synthesized in excess. These phages represent an interesting model for genetic and morphogentic studies.
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Consecutive subculturing of the same bacterial strain over a period of time resulted in variations of relative concentration of pyrolysis products. It is recommended that judicious care should be taken in the choice of these products used for taxonomic purposes.
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An indirect fluorescent antibody test was evaluated in 198 cases of a high-risk group with a culture prevalence of 37.3% and in 426 cases of a low-risk group with a culture prevalence of 1.16%. A sensitivity of 77.1% in the culture-positive patients with uncomplicated gonorrhoea, and a specificity of 88.7% in the culture- and history-negative cases, was obtained in the high-risk group. In this group, the sera from 88.8% of the patients with culture-proven gonorrhoea became positive in an indirect fluorescent antibody test within 3 weeks of last sexual contact. In the low-risk group, for which the sensitivity could not be determined due to various reasons, a specificity of 95.8% was obtained. Complement fixation test was positive in sera of only 17.6% of the culture-positive cases of the high-risk group.
Streptococci of Lancefield group D were isolated from 52.2% of pharyngeal, 55.5% of urethral, 56.6% of endocervical, and 75.4% of ano-rectal specimens. Seventeen phages isolated from sewage and urogenital specimens were selected for phage typing. Four of these lysed only the strains of Streptococcus faecalis and its variety liquefaciens. Another six phages lysed only the strains of Streptococcus faecium and its variety durans. With the help of seven bacteriophages, 346 of 384 (90.1%) strains of S. faecalis and its variety liquefaciens could be classified into 27 types. Similarly, with the help of 10 other bacteriophages, 97 of 117 (82.9%) strains of S. faecium and its variety durans could be grouped into 22 types. In 72 of 87 (82.7%) cases, similar phage types were obtained at different culture sites of the same individual.
Phage VD13 possesses a large, elongated head and a long, non-contractile tail. It is active on group D streptococci and contains double-stranded DNA. The phage produces several rare kinds of head malformations, notably polymorphic mottled structures and giant heads which probably contain DNA.
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