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Showing papers in "Annual Review of Microbiology in 1949"


Journal ArticleDOI
TL;DR: Bacterial growth is considered as a method for the study of bacterial physiology and biochemistry, with the interpretation of quantitative data referring to bacterial growth limited to populations considered genetically homogeneous.
Abstract: The study of the growth of bacterial cultures does not constitute a specialized subject or branch of research: it is the basic method of Microbiology. It would be a foolish enterprise, and doomed to failure, to attempt reviewing briefly a \"subject\" which covers actually our whole discipline. Unless, of course, we considered the formal laws of growth for their own sake, an approach which has repeatedly proved sterile. In the present review we shall consider bacterial growth as a method for the study of bacterial physiology and biochemistry. More precisely, we shall concern ourselves with the quantitative aspects of the method, with the interpretation of quantitative data referring to bacterial growth. Furthermore, we shall considerz exclusively the positive phases of growth, since the study of bacterial \"death,\" i.e., of the negative phases of growth, involves distinct problems and methods. The discussion will be limited to populations considered genetically homogeneous. The problems of mutation and selection in growing cultures have been excellently dealt with in recent review articles by Delbriick (1) and Luria (2). No attempt is made at reviewing the literature on a subject which, as we have just seen, is not really a subject at all. The papers and results quoted have been selected as illustrations of the points discussed.

4,104 citations





Journal ArticleDOI

19 citations



Journal ArticleDOI
TL;DR: On the basis of several thoroughly worked-over examples, it is inclined to generalize acquired resistance as being the result of a specific antibody response to an antigen possessed by the infectious agent.
Abstract: In this review attention will be centered upon the fundamental immunological considerations which determine protective immuni­ zation against infectious organisms; that is, the modifications in the host which serve as protective devices and the constituents of the infectious agents responsible for the induction of resistance. Only the essence of clinical statistics will be dealt with; sufficient to indicate the practical usefulness of the individual immunizing procedures. On the basis of several thoroughly worked-over examples, we are inclined to generalize acquired resistance as being the result of a specific antibody response to an antigen possessed by the infectious agent. Clear evidence for this mechanism is actually limited to relatively few well-known examples-the pneumococcus, the hemolytic streptococcus, the gram negative enteric bacilli, the antiKenic toxins, and perhaps some of the viruses, such as those of influenza, rubeola, and mumps where, when the virus is in the blood phase at least, antibodies may effectively inhibit the disease. In many of the bacterial diseases it has not been possible as yet to correlate the presence of antibodies with the immune state, and it seems obvious that with those agents-the viruses and rickett­ siae-in which the relation of organism to host is intracellular, antibodies may never have sufficient opportunity to act even though they might be able to influence the agent if the chance were afforded. In the case of the bacteria mentioned above, the immunizing. factors appear also to be important "virulence factors." Antibody immunity therefore serves to overcome or neutralize an aggressive property of the infecting organism. Although this kind of joust seems entirely reasonable from analogies in human activities, it is certainly conceivable that the host may "choose" to ignore the

13 citations



Journal ArticleDOI
TL;DR: A review of recent trends in techniques with an indication of the reference material can be found in this paper, where the authors focus mainly on the techniques for study of the bacteria and their products, though some reference will be made to other microorganisms.
Abstract: Within the limited space available for this review obviously it will not be possible even to list, much less to evaluate, each of the newly devised tools and/or techniques which have appeared in recent years. Therefore, this account will be concerned mainly with recent trends in techniques with an indication of the reference material. Since a particular technique often is concerned with new ap­ paratus, or with further use of instruments already known, men­ tion will also be made of some of the reference material concerning specialized apparatus currently being used in microbiological lab­ oratories. Although this topic has not been reviewed recently, only publications which have appeared within the last few years will be included and often the references cited are intended to be illustrative and not as a complete bibliography. Owing to space limitations and the field of interest of the re­ viewer, this summary will be concerned mainly with the techniques for study of the bacteria and their products, though some reference will be made to the other microorganisms. This review will not contain many references to new or revised procedures for staining microorganisms (these are abstracted in Stain Technology and elsewhere) nor formulae of media, specific cultural reactions, or procedures of interest mainly to the clinical or diagnostic labora­ tories. Material of the latter nature may be found in such books as those of Gradwohl (134), Marshall et al. (259), Mackie & Mc­ Cartney (256), Schaub & Foley (329), Stitt, Clough & Branham (351), Wadsworth (388), or the Pure Culture Study of Bacteria (302) issued by the Committee on Technic of the Society of Ameri­ can Bacteriologists. Other recent books which include, or are de­ voted exclusively to, discussions of techniques relate to viruses (118), histoand cytochemistry (130), immunochemistry (195), immunology (50), enzymes (358, 366), biochemical preparations (71) and general laboratory techniques (65,99,153, 190). Mention

7 citations


Journal ArticleDOI

6 citations



Journal ArticleDOI
TL;DR: It is shown that gram positive organisms (staphylococci) require an external source of glutamic acid, and that the assimilatory mechanism is blocked by penicillin, and the same microbes, made highly resistant to peniillin, become like gram negative bacteria and are able to synthesize their own glutamic Acid.
Abstract: Antibiotic action.-As with most drugs, the fundamental mode of action of penicillin is not clear. Two superficial facts are well known, i.e., that gram positive bacteria are more susceptible than gram negative and that the division and growth of bacteria are im­ peded with the formation of bizarre forms when early death or lysis is not produced. Pandalai & George (1) associate these effects with an interference with the nucleic acid metabolism of the bac­ teria, which coincides with the observation that gram positiveness is associated with the presence of magnesium ribonucleate. Gale and co-workers in a series of papers (2) show that gram positive organisms (staphylococci) require an external source of glutamic acid, and that the assimilatory mechanism is blocked by penicillin. The same microbes, made highly resistant to penicillin, become like gram negative bacteria and are able to synthesize their own glutamic acid. These two views may be compatible if it is assumed that the glutamic acid becomes a constituent of nucleoprotein. A paradoxical effect has been reported by Eagle (3) and Pratt & Dufrenoy (4), in which high concentrations of penicillin, in vitro, are less effective against several common microorganisms than lower concentrations. Still lower concentrations, of course, are again less effective. The latter authors also note an enhancement of effect when traces of cobalt are present, perhaps because this element stimulates growth of the bacteria and thereby increases their susceptibility to penicillin.