Showing papers in "Microbiological Research in 1984"

Mutagenesis and inducible responses to deoxyribonucleic acid damage in Escherichia coli.

Abstract: INTRODUCTION............................................................ 61 PROCESSING OF DAMAGED DNA ............................................................ 61 SOS REGULATORY NETWORK ............................................................. 61 Present Model for SOS Regulation ............................................................ 62 SOS Responses ............................................................ 62 Development of the Model for SOS Regulation .................................. .......................... 64 Genetic studies of recA and lexA .6....................................4i................... 64 Deduction of the essential elements of SOS regulation .......................................................... 65 Identification of genes in the SOS network............ ............ 66 Biochemical studies of SOS regulation............................................................ 67 SOS-Inducing Signal ............................................................ 67 Central role of RecA activation ............................................................. 67 Agents and treatments which cause SOS induction ............................................................ 68 Indirect induction.6.............................. . . . .. . .. . .. . . 68 Role of DNA replication ............................................................ 68 Involvement of small molecules .................................... ...................... . .68 Role of single-strand DNA-binding protein ........................................................... 69 Fine Tuning in the Induction of the SOS System ........................................................... 69 Intermediate states of induction.............................................................69 Factors influencing the extent of SOS induction ............................................................ 70 Strategies for modulating individual genes within the SOS network....................................... . 70 INDUCTION OF HEAT SHOCK GENES BY DNA-DAMAGING AGENTS .................................... 71 ADAPTIVE RESPONSE TO METHYLATING AND ETHYLATING AGENTS ........... ................... 71 Biochemistry of the Adaptive Response ................. ........................................... 72 06-Alkylguanine-DNA alkyltransferase .................. ......................................... 72 3-Methyladenine-DNA glycosylase II............................................................. 72 Regulation of the Adaptive Network .............. .............................................. 72 Effect of the Adaptive Response on Mutagenesis................................ ........................... 72 Comparison of the SOS, Heat Shock, and Adaptive Regulatory Systems ............... ....................... 73 ROLE OF SOS PROCESSING IN MUTAGENESIS ............................................................ 73 Mutagenesis by UV and Most Chemicals Is Not a Passive Process ....................... ....................... 73 Weigle reactivation and Weigle mutagenesis ............................................................. 73 Bacterial mutagenesis ............................................................. 74 Significance of umuD and umuC Mutations ............................................................. 74 Isolation of umuD and umuC mutations............................................................. 75 Identification of the umuD and umuC gene products ............................................................ 75 umuD and umuC Analogs on Naturally Occurring Plasmids ...................................................... 75 pKM101 ............................................................. 75 Relationship of pKM101-mediated processes to cellular gene functions ...................................... 76 mucA and mucB genes of pKM101 are analogs of umuD and umuC ............... ......................... 76 Distribution of umuDC functions in other bacteria ............................................................. 76 A Second Requirement for the RecA Protein in Mutagenesis .................................................... 77 Effect of the recA430 mutation on mutagenesis ............................................................. 77 Evidence suggesting that UV mutagenesis does not require the induction of genes other than those repressed by LexA ..................................................... 77 Other evidence...................................77 Targeting of UV and Chemical Mutagenesis ................................ 78 Most UV and chemical mutagenesis is targeted ........................................................ ..78 Hotspots ......................................................... 78 Concept of HFOs and LFOs ......................................................... 79 (i) HFOs ......................................................... 79 (ii) LFOs ........................................................... 79 Consequences of SOS Processing of DNA Not Damaged by Exogenous Agents ........... ................... 79 Relationship of SOS processing to the spontaneous mutation frequency ............ ........................ 79 Mutagenesis of undamaged bacteriophage in SOS-induced cells which depends on SOS processing 80

Regulation of trehalose mobilization in fungi.

Abstract: INTRODUCTION............................................................... 42 TREHALOSE ...................... . .. .... .... .... .. . .. ............. 42 Occurrence in Fungi............................................................... 42 Accumulation and Mobilization in the Life Cycle .......................................................... 42 Function of Trehalose ............................................................... 43 TREHALASE ............................................................... 44 Nonregulatory and Regulatory Trehalases............................................................... 44 Activity During the Life Cycle ........................................................ 45 Nonregulatory trehalases ............................................................... 45 In vivo activation of regulatory trehalases ................................. .............................. 46 SUBCELLULAR LOCALIZATION OF TREHALOSE AND TREHALASE ............. ....................... 47 REGULATION OF TREHALOSE MOBILIZATION ............................................................... 47 Regulation of Trehalase at the Transcriptional Level............................................................... 47 Compartmentation of Trehalose and Nonregulatory Trehalases .................................................. 48 cAMP-Induced Phosphorylation of Regulatory Trehalases ........................................................ 49 The glucose-induced, cAMP-dependent phosphorylation cascade.............................................. 49 Cellular cAMP levels and the basal activity of regulatory trehalase ..........................04009000069 51 Activation of regulatory trehalase by nitrogen sources in the presence of glucose 51 Activation of regulatory trehalase in fungal spores by heat shock ................. ............................... 52 Activation of regulatory trehalase and the induction of fungal spore germination ..............o ........... 52 Other Mechanisms...................................... . ..................... 53 CONCLUSIONS. ......................... ..................................... 54 ACKNOWLEDGMENTS ............................................................... 54 LITERATURE CITED ............................................................... 54

Processing of plasmid DNA during bacterial conjugation.

Abstract: Coupure et initiation du transfert d'ADN au site d'origine de transfert, separation des 2 brins d'ADN plasmidiques, transfert des brins, synthese d'ADN dans les cellules donneuses et receptrices et recircularisation des molecules de plasmides repliquees

Mechanisms of microbial resistance and detoxification of mercury and organomercury compounds: physiological, biochemical, and genetic analyses.

Abstract: METHYLATION OF MERCURY BY MICROORGANISMS ..................................... 96 Mechanism of Methylation of Mercury....................................................... 96 Methylmercury Formation Under Anaerobic Conditions ........................................ 97 Methylmercury Formation Under Aerobic Conditions .......................................... 97 Effects of HgS on Methylation of Mercury .......... .......................................... 98

Biology of bacterial deoxyribonucleic acid topoisomerases.

Abstract: INTRODUCTION .......................................................................... DNA SUPERCOILING AND TOPOISOMERASES ............................................. CONTROL OF TOPOISOMERASE GENE EXPRESSION ...................................... ROLE OF TOPOISOMERASES AND SUPERCOILING IN DNA REPLICATION................. Elongation Phase of Replication ............................................................ Initiation of Replication ................................................................... Termination of Replication ................................................................ Plasmid Replication In Vivo ............................................................... ROLE OF TOPOISOMERASES AND SUPERCOILING IN GENE EXPRESSION................. CELLULAR RESPONSES TO NALIDIXIC ACID............................................. TOPOISOMERASES, RECOMBINATION, AND REPAIR ...................................... Generalized Recombination. .. ............................................................ Site-Specific Recombination. .. ............................................................ Gyrase-Mediated Illegitimate Recombination. .. ............................................. DNA Repair............................................................................ CONCLUDING REMARKS ................................................................. ACKNOWLEDGMENTS .................................................................... LITERATURE CITED..................................................................... 273 274 276 277 277 279 279 280 280 281 282 282 282 283 284 285 285 285

Regulation of plasmid replication.

Abstract: Article de synthese sur la regulation de la replication chez les plasmides avec etude du plasmide, Col E 1, des plasmides du groupe d'incompatibilite FII, du plasmide pT 18 1, des plasmides du groupe d'incompatibilite F 1 , du plasmide P1 et du plasmide RGK