Showing papers in "Bacteriological Reviews in 1977"

Energy conservation in chemotrophic anaerobic bacteria.

Abstract: [This corrects the article on p. 100 in vol. 41.].

Extracellular enzyme synthesis in the genus Bacillus.

Abstract: As the decade progresses this prediction is rapidly being realized, and microbial enzymes are becoming increasingly important in such diverse fields as medicine, brewing, and timber preservation. The genus Bacillus has played a major role in this development as evidenced by the distribution of the papers read at the Fifth International Fermentation Symposium, 1976 (64). Of 23 papers in the session devoted to "Microbial Enzymes of Industrial Interest" no less than ten were concerned with enzymes from bacilli. Reasons for the predominance of these bacteria in this area of study are several. First, they comprise a group of chemoorganotrophs that can be easily maintained and cultivated and yet are markedly heterogeneous in character. Psychrophiles, mesophiles, and thermophiles, in addition to alkalophilic, neutrophilic, and acidophilic species are well represented. Furthermore, virtually all 48 species of the genus listed in Bergey's Manual ofDeterminative Bacteriology (92) secrete a variety of soluble extracellular enzymes, which reflects the diversity of the parental habitats. Amylases that can liquefy starch under pressure at 11000 (194) and proteases that are stable and active at pH 12.0 (6) are extreme examples of enzyme adaption. This article will attempt to review the recent literature concerned with the characterization and properties of the exoenzymes synthesized by the bacilli and the control and mechanisms of their synthesis. It is restricted to this genus because the commercial importance of extracellular enzymes and academic interest in the process of sporulation have prompted a considerable amount of research into this general area. Nevertheless, in the final section I have attempted to equate our present knowledge of exoenzyme synthesis in procaryotes other than

The biology of methanogenic bacteria.

Abstract: [This corrects the article on p. 517 in vol. 41.].

Environmentally induced changes in immunological function: acute and chronic effects of inhalation of tobacco smoke and other atmospheric contaminants in man and experimental animals.

Abstract: Attention is drawn to the long-term effects of atmospheric contaminants in general (and cigarette smoke in particular) on immunological control mechanisms that are accepted as playing a vital role in the maintenance of health. The review argues that a hostile environment within the respiratory tract created by inhalation of air contaminants compromises local immunological function in the short term, and ultimately depresses systemic immunological function. Whether such a decline in immunological homeostasis is due directly to toxicity, or indirectly to accelerated aging of susceptible elements of the immune system, is speculative. The changes observed in both man and experimental animals exposed for long periods to air contaminants in many respects parallel those associated with normal aging and may represent an acceleration of the process of senescence. Specific biological effects of smoking, air pollution and immune functions in man and animal models are reviewed. The precise mechanism(s) by which air contaminants affect immunological function remains speculative, but the relative resistance of specified-pathogen-free animals to these agents infers a central role for the hosts' normal bacterial flora in the process.

Antiviral activity of interferons.

Abstract: INTRODUCTION.............................................................. 543 ESTABLISHMENT OF THE ANTIVIRAL STATE ........... .................... 544 Interferon Binding ................... ............................. 544 Development of Antiviral Activity................................. 546 LOCUS OF THE INTERFERON-INDUCED INHIBITION OF VIRUS GROWTH. . 547 Evidence that Interferon Treatment Inhibits Virus Uncoating ....... ........... 547 Evidence that Interferon Treatment Inhibits Transcription of the Viral Genome. 547 Evidence that Interferon Treatment Inhibits Viral Protein Synthesis ..... ...... 550 Observations in virus-infected cells ........................... 551 Observations in cell-free systems ....... .................... 552 Evidence that Interferon Treatment Inhibits Terminal Events in the Replication Cycle of Murine Leukemia Viruses ........ ................. 557 INTERFERON TREATMENT IS INEFFECTIVE IN SYSTEMS IN WHICH THE SV40 GENOME IS INTEGRATED INTO AN INTERFERON-RESISTANT VIRUS OR A HOST GENOME ........................... 559 DISCUSSION ............................. 560 LITERATURE CITED........................... 562

Fusobacterium necrophorum: its characteristics and role as an animal pathogen.

Abstract: INTRODUCTION.............................................................. 373 CLASSIFICATION ......... 374 DESCRIPTION OF F. NECROPHORUM. 376 Cellular Morphology ................................... 376 Lipopolysaccharide ................................... 376 Toxins ................................... 377 Biochemical Properties ........ ........................... 378 Serological Properties .................................... 378 Antibiotic Sensitivities ........ ............................ 381 Isolation and Cultivation .................................... 381 ANIMAL DISEASES AND CHEMOTHERAPY .................................. 382 Natural Infections .................................... 382 Calf diphtheria .................................... 382 Liver abscesses .................................... 383 Foot rot .......................................... 383 Other diseases .................................... 384 Experimental Infections ......... ........................... 385 IMMUNITY................................................................... 386 CONCLUDING REMARKS.................................... 387 LITERATURE CITED.................................... 387

Biosynthesis of aflatoxins.

Abstract: The role of zinc on the primary metabolism of Aspergillus parasiticus in relation to aflatoxin biosynthesis was studied. Zinc deficiency impaired growth and metabolism of nucleic acid and protein while stimulating that of lipid. The activities of enzymes of glycolytic cycle were affected indicating that these are zinc dependent enzymes. Impaired glycolytic cycle tends to reduce the level of primary metabolites like pyruvate, citrate and oxaloacetate which trigger aflatoxin formation. During stationary phase these precursors accumulate as these are not used up for the synthesis of secondary metabolites (aflatoxins) due to zinc deficiency. ATP and energy-charge (E.C.) which are important for various physiological processes like growth are reduced in zinc deficiency. Also zinc deficiency results in low levels of AMP which favour synthesis of lipid. Inorganic phosphate accumulated due to zinc deficiency and this may be unfavourable for aflatoxin synthesis.

Physiology and evolution of spirochetes.

Abstract: INTRODUCTION ........................................ 181 METABOLISM OF SPIROCHETES ................................... 182 Cultivation of Spirochetes ................................... 182 Anaerobic Energy-Yielding Metabolism ................................... 183 Aerobic Dissimilatory Metabolism ................................... 187 Physiology of T. pallidum ................................... 189 Lipids and Fatty Acids ................................... 189 Carotenoid Pigments ................................... 191 Motility and Chemotaxis ................................... 191 EVOLUTION OF SPIROCHETES ................................... 194 The Protospirochete Hypothesis ................................... 194 Convergent Evolution Hypothesis ................................... 195 Energy-Yielding Pathways of Spirochetes .................................... 195 Development of Associations with Hosts ................................... 197 Possible Relationship with Gliding Bacteria ................................... 197 Spirochetes, Eucaryotic Flagella, and Cilia ................................... 197 Concluding Remarks ................................... 198 Summary ................................... 198 LITERATURE CITED................................... 199

beta-Lysin of platelet origin.

Abstract: (3-Lysin is the name that Pettersson proposed to distinguish this thermostabile bactericidal component of serum from Buchner's alexin or a-lysin (51). He defined (8-lysin as the bactericidal substance found in normal serum that resisted inactivation when heated to 56°C for 30 min. According to this definition, there are at least three different ,3-lysins found in normal serum; these consist of lysozyme, ,B-lysin from platelets, and (8-lysin of nonplatelet origin. The first of these, lysozyme, is a single entity which is well defined in regard to its chemical and biological properties. The other two types of (3lysins are not readily distinguished from each other, and each could be composed of several distinct molecules. The ,B-lysin of platelet origin may be similar or identical to plakin (23). The (8-lysin of nonplatelet origin may include the bactericidal cationic proteins isolated from leukocyte lysosomes (64-66). In this review, attention will be focused on the (3-lysin of platelet origin, which will be referred to as \"platelet (3lysin.\