bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in the nuclear structure of bacteria, particularly during spore formation
Authors: Klieneberger-Nobel Emmy 
Published: May 2009

Changes of nuclear structure in bacteria have been studied by means of the hydrochloric acid-Giemsa method which produces brilliantly stained specimens and can be carried out with almost the same ease as some of the ordinary routine staining techniques.The nuclear changes in the four spore-bearing organisms studied are outlined in Text-fig. III, to which the following numbers refer. The dumbbell bodies which are dispersed in the cells of the young growth (1) become alined in the long axis of the cell (2) where they eventually fuse into an axial nuclear cylinder (3, 4). These cells divide up into fusion cells of approximately the same length (5). The development of the ‘chromosome’ stage (1) into the fusion cell (5) is the first step in the process of sporulation. During its further development the fusion cell or spore mother cell divides twice (6, 7), with the result that it is segregated into four structures which often assume dumbbell shape. Therefore the chromatin cylinder of the individual spore mother cell seems to be equivalent to four nuclear elements one of which functions as the spore ‘chromosome’ (‘nucleus’?), whereas the remaining three disintegrate (8, 9). The ripe spore (9) representing, as it does, the smallest cell unit contains one nuclear structure only.Therefore the two main features in spore formation of bacteria appear to be (1) a fusion of the dumbbell bodies into an axial chromatin rod (‘autogamy’?), (2) a reduction partition which is reminiscent of, though not corresponding to, the more complicated phenomenon of meiosis in the higher organisms. The sporulation, as outlined in this paper, gives new proof of the important part played by the chromatinic dumbbell bodies (‘chromosomes’) in the developmental cycle of spore-bearing organisms. The fusion cell with its axial chromatin cylinder has for the first time been proved to have a progressive functional significance as a stage in a nuclear cycle. The particular mode of fusion followed by reduction partition suggests that the chromatinic dumbbell bodies may be concerned with the transmission of the hereditary characters in bacteria.
Bacterial lysis and antiseptics
Authors: Pulvertaft R. J. V. , Lumb G. D. 
Published: May 2009

When a number of organisms are exposed in early rapidly multiplying broth cultures to minimally effective bacteriostatic concentrations of a number of antiseptics, almost complete lysis may be demonstrated.When older cultures are exposed to low concentrations, or young cultures to strong concentrations, lysis does not occur in many cases.The lytic effect of penicillin is apparently identical with that of the antiseptics tested. The phenomenon appears to depend on the nature of the effect of the antiseptic on metabolic enzymes, autolytic enzymes, or both.
Cross-infection in hospital due to Salmonella derby
Authors: Rubbo Sydney D. 
Published: May 2009

1. An outbreak of gastro-enteritis in hospital due to Salmonella derby is described.2. The probable pathways of infection are indicated diagrammatically (Text-fig. 2).3. Attention is drawn to the importance of dust as an environmental source of infection in gastroenteritis in a closed community.4. Methods of control including the detection of carriers, the avoidance of contact with anything that goes into an infant's mouth and the protection of exposed food from dust contamination are stressed.
Haemolytic disease of newborn foals due to iso-immunization of pregnancy
Authors: Coombs R. R. A. , Crowhurst R. C. , Day F. T. , Heard D. H. , Hinde I. T. , Hoogstraten J. , Parry H. B. 
Published: May 2009

1. Six cases of haemolytic disease in newborn foals apparently due to iso-immunization of pregnancy are described from their clinical, serological, haematological and pathological aspects. The findings agree closely with those seen in the same disease in newborn mules.2. The disease may be diagnosed serologically by demonstrating the in vivo iso-sensitization of the foal's red cells by means of the direct antiglobulin-sensitization test. It is quite possible that after further investigation a modification of Diamond's albumin tube test may also be of value. Immune anti-red cell iso-antibodies of more than one specificity may be demonstrated in the dams' sera.3. Despite the acute haemolytic process, very few reticulocytes and no erythroblasts are seen in the peripheral blood.4. The morbid histology of the tissues of foals dying with the disease exhibits various points of interest which are discussed.5. The clinical aspect is not described in this paper in any detail. However, a programme is suggested which would enable a successful exsanguino-transfusion of compatible blood to be carried out at very short notice. At present this seems to be the logical and most practical method of specific treatment.
A study of rheumatic fever and streptococcal infection in different social groups in Melbourne
Authors: Holmes Margaret C. , Rubbo Sydney D. 
Published: May 2009

1. Hospital records of 1469 cases of rheumatic fever (including chorea) up to the age of 14 years were used to study the social distribution of the disease in Melbourne. On this evidence the incidence of rheumatic fever was three times greater in low than in high rental districts.2. The results of throat-swab surveys and Dick tests on schoolchildren living in different districts showed that children in the poor districts contracted streptococcal infections more frequently than those in well-to-do districts.3. One factor associated with the carrier rate ofStreptococcus pyogenesin the various social groups was the incidence of tonsillectomy. In the better class districts where the tonsillectomy rate was high (60%) theStr. pyogenescarrier rate was 12.5%, whereas the rates in poor areas were 35 and 25.3% respectively.4. Differences in social incidence of rheumatic fever might therefore be explained by differences in social incidence of streptococcal infection, which, in turn, might be influenced by the incidence of tonsillectomy.We wish to thank the many persons who so willingly assisted in the collection of data for this study, particularly Dr H. L. Stokes and Dr M. M. Wilson, and Dr R. E. O. Williams for advice on presentation. This work was supported by a grant to one of us (Dr M. C. Holmes) from the Commonwealth Research Fund from the University of Melbourne.
Enumeration ofStreptococcus faecalis, with particular reference to polluted waters
Authors: Allen L. A. , Pierce Margaret A. F. , Smith Hazel M. 
Published: May 2009

Factors affecting the growth ofStreptococcus faecalison glucose-yeast extract-sodium azide agar have been studied. Both the high temperature of incubation used (45° C.) and the presence of azide reduced the proportion of cells able to form colonies, the inhibitory action being much more marked with cultures which had become attenuated, either through age or through prolonged immersion in water, than with comparatively young and vigorous cultures. This inhibitory action was found to be largely overcome if the inoculum was subjected to a preliminary period of ‘resuscitation’, by incubating it with double-strength glucose broth before adding the azide-agar portion of the medium and allowing the mixture to set.Neutral red was so inhibitory to some strains ofStr. faecalisthat it could not be included in the medium. Phosphate, as the potassium salt at a concentration of 0.7%, if autoclaved with the remaining constituents of the medium, exerted a depressing effect on the counts. Added separately it showed no inhibitory action.The spinning-bottle technique (Allenet al.1952) was adapted forStr. faecalis. When used for samples containing a mixed flora the method, described in the Appendix, permitted the growth only ofStr. faecalis.This paper is published by permission of the Department of Scientific and Industrial Research.
Improved methods for determining the most probable number ofBacterium coliand ofStreptococcus faecalis
Authors: Childs Eileen , Allen L. A. 
Published: May 2009

Three methods have been investigated for determining Most Probable Numbers, using lactose-bile salts broth forBacterium coliand glucose-yeast extract-azide broth forStreptococcus faecalis. In the ‘direct’ method inoculated tubes of medium are incubated directly in a water-bath, at 44° C. forBact. colior at 45° C. forStr. faecalis. In the ‘subculture’ method primary incubation at 37° C. is followed by subculture of positive tubes to tubes of fresh media which are incubated at the higher temperature. In the ‘resuscitation’ method each medium is divided into 2 parts. The inoculum is mixed, in McCartney bottles or tubes, with the first part of the medium, containing the sugar and the peptone, and the mixture is held at 37° C. for 1–2 hr. to resuscitate organisms weakened by age or by long immersion in water. The second part of the medium, containing the bile salts or the azide, is then added and the bottles or tubes are incubated at 44 or 45° C. With samples of polluted waters the ‘subculture’ method gives significantly higher counts than the ‘direct’ method forStr. faecalisbut not forBact. coli.The ‘resuscitation’ method gives significantly higher results than the ‘subculture’ method for both organisms, it requires less time for completion, and is specific for the organism concerned.These results were obtained with media containing 0.003% brom-cresol purple as indicator; neutral red was found to be inhibitory.This paper is published by permission of the Department of Scientific and Industrial Research.
A group of viruses isolated from naturally infected mosquitoes collected in the Murray Valley area of Victoria and New South Wales
Authors: French E. L. , Reeves W. C. 
Published: May 2009

By the inoculation of suspensions of mosquitoes on the chorio-allantoic membrane of chick embryos, seven pock-producing viruses have been isolated. The mosquitoes were collected in a small area of the Murray Valley situated in the north-western corner of Victoria and southern New South Wales. Six of the viruses were isolated from pools ofC. fatigansand one from a pool ofC. annulirostris. Five of the viruses were found to be members of the bird pox group and related to fowl-pox virus. Two of the viruses differed in the type of pock they produced on the chorio-allantoic membrane and appeared to be serologically unrelated to the other five.The interest and criticism of Sir Macfarlane Burnet, F.R.S., throughout the conduct of this work is gratefully acknowledged.
Tetanus antitoxin titration by haemagglutination
Authors: Fulthorpe A. J. 
Published: May 2009

The behaviour of sheep cells sensitized with tetanus toxins and toxoids in the presence of antitoxin has been investigated.Sensitized sheep cells were agglutinated in the presence of tetanus antitoxin. The agglutinin titres of such direct agglutinin systems were roughly proportional to the antitoxin content of the sera with some marked exceptions. The discrepancies were associated with the presence of non-specific agglutinins (antibodies other than specific antitoxin) and with the immunization history of the horses providing the sera.When sensitized cells were used as indicators of the presence of free antitoxin in toxin or toxoid-antitoxin mixtures, the correlation within vivotests was quite good at the L+ level of test, but not so reliable at the 0·01 L+ level of test.Sensitized cells preserved with formalin were found to be more reliable and the results with such materials were more reproducible than those obtained with freshly prepared sensitized cells.Cells sensitized with different concentrations of antigen gave different titres by direct agglutination with simple dilution of antitoxin; this difference was very much less in haemagglutination inhibition tests.The LAdose (the volume of toxin or toxoid which when mixed with one unit of antitoxin gave a + + ± end-point) varied according to the sensitivity of the suspension used and the purity of the components of the reacting mixtures.Prozones (zones of agglutination inhibition in the region of antibody excess) were found to be associated with the immunization history of the horses from which the sera were obtained. In general the more thorough the immunization the longer the prozones found. The length of prozones was proportionately increased with decrease in the concentration of sensitizing antigen. Possible reasons for the behaviour of certain antitoxins in these tests have been discussed.I am indebted to Prof. M. Raynaud of the Pasteur Institute, Garches, for the supply of tetanus toxoids of high purity.I am very grateful to Mr Charles Newman for considerable technical assistance.
An intra-oral inoculation technique for the production of experimental pneumonia in mice
Authors: Epstein S. S. , Breach G. D. 
Published: May 2009

Techniques for the production of experimental pneumonia are briefly reviewed. A new method of intra-oral inoculation in the anaesthetized mouse is described and its advantages with particular reference to the danger of aerial contamination and facility of technique discussed. An application of this method to virulence studies is indicated and other possible applications suggested.The author would like to express gratitude to Dr I. Friedmann for having made this work possible and for his advice and help at all stages. He would also like to thank the late Sir E. L. Kennaway, Dr F. Fulton and Dr D. A. Osborn for helpful suggestions, Prof. E. T. C. Spooner for the kind loan of the Bourdillon apparatus, Dr S. T. Cowan for an N.C.T.C. strain of Klebsiella, Mr P. Payne for statistical advice and Mr D. Connolly for the photomicrograph.
The fimbrial antigens ofShigella flexneri
Authors: Gillies R. R. , Duguid J. P. 
Published: May 2009

1. ‘Pure fimbrial antisera’ were prepared forSh. flexneristrains of O-serotypes 1a, 2b, 3 and 4aand 5, by injecting rabbits with a living fimbriate-phase culture and absorbing the crude immune serum with a non-fimbriate-phase culture of the same strain to remove antibodies for the non-fimbrial (somatic) antigens. These sera gave at high titre a rapid, loosely floccular agglutination of all fimbriate-phaseFlexnericultures, caused adhesion of their fimbriae visible by electron-microscopy and inhibited their haemagglutinating activity. ‘Non-fimbrial antisera’, prepared by injection of non-fimbriate-phase cultures, were devoid of these activities; they gave somatic-type agglutination with fimbriate bacilli at lower titres than with homologous non-fimbriate bacilli, the fimbriae tending to mask the O-antigens and confer relative O-inagglutinability.2. Heating at 90°C. detached the fimbriae from the bacilli, so that these lost their haemagglutinating activity, fimbrial serum agglutinability and fimbrial agglutinin-binding power. When heated for 21/2 hr. at 100°C., the detached fimbriae retained agglutinin-binding power, but lost their immunogenicity.3. Cross-agglutination and absorption tests showed that the antigenic composition of the fimbriae was identical in allflexneristrains, irrespective of O-serotype. Theflexneripure fimbrial antisera agglutinated at low titre sixty out of sixty-six fimbriateBact. colistrains. Absorption tests with aflexneriand threecolipure fimbrial antisera showed that the fimbriae ofSh. flexnericontained a major‘flexneri-specific antigen’, found in only onecolistrain, one or more minor ‘flexneri-coliantigens’ shared by a fewcolistrains. Thecolifimbriae also contained a major,‘colitype-specific antigen’ shared in groups of several related strains. Theflexnerisera did not react with fimbriate strains ofBact. cloacae, SalmonellaandProteus.4. Fimbrial agglutinins forSh. flexneriwere found in eighty of eighty-one normal human sera at titres from 30 to 1920, and in some pre-immunization rabbit sera at titres of 30 to 60.
Epidemiology of staphylococcal infections
Authors: Roodyn Leonard 
Published: May 2009

During the period 1951–58, a study has been carried out of a series of seventeen families in which more than one member developed a staphylococcal lesion.In eleven of these families, phage typing revealed that spread of infection from person to person had occurred. Once introduced into a household, the staphylococcus demonstrated great persistence; a particular strain could cause recurrent lesions in different members for as long as 6 years. The interval between the first and subsequent infection in another member of the same family was most irregular, but was usually 2–11 months.The patient with recurrent furunculosis appeared to be mainly responsible for dissemination of strains.In six out of the seventeen families, although multiple infections were encountered in the household, these were not due to case-to-case spread because more than one phage type of staphylococcus was isolated.In one family investigated, there had been a dissemination of a hospital-acquired staphylococcus to another member of the household.No infections were encountered in which the ‘epidemic strain’ 80/81 was responsible.I wish to express my gratitude to Dr R. E. O. Williams of the Staphylococcal Reference Laboratory, Colindale, for his assistance in this work.
Further observations on an insecticide-bait-box method for the control of sylvatic plague vectors; effect of prolonged field exposure to DDT powder
Authors: Kartman Leo 
Published: May 2009

A field experiment was conducted from July 1958 to February 1959 in the San Francisco Bay region to test the effect on flea populations of prolonged exposure of the native meadow vole, Microtus californicus, to 5% DDT powder in insecticide-bait-boxes. Previous studies had shown that two important vectors of sylvatic plague, Malaraeus telchinum and Hystrichopsylla linsdalei, could be controlled both on their hosts and in the host nests by this method. However, the question of possible resistance was postulated since the control of H. linsdalei on its host was inferior to control of other flea species.Bait-boxes with DDT powder were maintained in the field for 6 months. Records of flea populations on Microtus during this period showed equally good control of all flea species. Observations on vole nests at termination of the study revealed deposits of DDT and good control of all flea species in them. During the period of study, the evidence suggested that none of the flea species involved exhibited DDT resistance.The major portion of the field routine was done by Messrs A. R. Kinney and R. L. Martin. Flea identifications were made by Mr H. E. Stark. Analyses of nests and rodents for DDT were performed by Mr C. Cueto, Technical Development Laboratories, CDC, Savannah, Georgia.
The evaluation of ventilation
Authors: Lidwell O. M. 
Published: May 2009

The problem of describing quantitatively the effective ventilation in a room when the air within the room is imperfectly mixed is discussed. It is suggested that the protection afforded by the ventilation to any given position against airborne contamination liberated at any other position can be best expressed in terms of the integrated exposure at the first point following liberation of a tracer substance at the second. This quantity is called thetransfer indexand its reciprocal theequivalent ventilationapproaches numerically to the rate of supply of ventilating air as the mixing of air within the room approaches completeness. Nitrous oxide is a convenient tracer gas for making such measurements.A method is also described whereby estimates of thetransfer indexcan be made employing only such apparatus as is easily available in a reasonably well-equipped laboratory. This method employs acetone vapour as a tracer substance. The concentration of this vapour in the air is measured by the pH change produced in a dilute solution of hydroxylamine hydrochloride as it flows down a cotton wick exposed to the atmosphere.
Observations on a poliovirus variant
Authors: Austin F. J. , Miles J. A. R. 
Published: May 2009

1. Some of the biological and physical properties of one member (FES) of an inter-related group of viruses were examined and compared with the Saukett strain of poliovirus Type 3.2. The accumulated data of particle size, immunological relationship, and host tissue and cell tropism indicates that this is a naturally occurring non-neurotropic strain of poliovirus Type 3. It shows a slight immunological difference from Saukett, and also differs from it in temperature stability.3. The significance of four different isolations of this agent in a brief period is discussed.
An environmental survey of bakehouses and abattoirs for salmonellae
Authors: Harvey R. W. S. , Phillips W. Powell 
Published: May 2009

1. Moore's gauze swabs have, in our hands, been shown to be a reliable instrument for the survey of salmonella infection in the environment of two food premises.2. A large bakery was demonstrated to be regularly contaminated with salmonellae. Thirty-one floor gully swabs out of 111 (27·9%) were positive for salmonellae. Little spread of infection to the general public was experienced.3. Staff infection with salmonellae was shown to occur in this bakery. Fifteen positive specimens of staff sewage out of 93 were obtained (16·1%). There was little evidence of prolonged contamination of the sewers with salmonellae. Staff infections were probably, therefore, of short duration. The staff probably became infected from contaminated goods in the bakehouse. Rat contamination of sewers was excluded by water trapping.4. It is not thought that regular examination of staff excreta would be a profitable means of discovering carriers or of preventing contamination of the products. The frequency with which such examinations would have to be performed to discover short-term excreters would be administratively impossible.5. Of 274 swabs from gullies in abattoirs, 111 were positive for salmonellac (40·5%). Twenty-one different serotypes were isolated. Seventeen of these serotypes are known to occur in animal feedingstuffs.6. Parallel examination of abattoir swabs and excreta from human infections forS. typhimurium, coupled with phage-typing of the strains, provided information of the geographically local nature of much sporadic illness due to this serotype. Of a total of 30 typable strains, 23 belonged to phage-types found in the abattoirs, or on local farms. Sporadic incidents were represented by 25 of these cultures, 18 of which corresponded in phage-type to those found in the abattoirs or in local farm animals. The phage-types ofS. typhimuriumisolated from the slaughter houses not infrequently corresponded in timing with the strains isolated from human infections.
The epidemiology of infectious hepatitis in Israel
Authors: Davies A. Michael , Suchowolski A. 
Published: May 2009

1. The incidence of infectious hepatitis calculated from official notifications fluctuated between 5·7 and 11·4 per 10,000 during the years 1949–57, while reports of the Workers' Sick Fund indicated a rate three to four times greater. The highest rates were between the ages 1 and 9, two-thirds of the cases being under 10. Mortality was very low.2. Highest attack rates were seen under conditions of crowding, i.e. in agricultural schools, communal settlements and new immigrant towns. This fact, together with the winter peak of incidence, suggests a contact-respiratory form of spread.3. Immigrants, regardless of country, showed particular susceptibility during their first year or two in Israel. In the long run there was no difference in attack rate between immigrants from Western and from Middle Eastern countries, in spite of the known endemicity of the disease in the Middle East. In communities such as those from Yemen and North Africa, with large families and with, on the whole, a lower economic status, the mean age at onset was significantly younger. Among the non-Jewish population, the incidence was lower than expected due partly to under-reporting and partly, perhaps, to a mild form of the disease in the very young.