-
Volume 139,
Issue 11,
1993
Volume 139, Issue 11, 1993
- Genetics And Molecular Biology
-
-
-
Analysis of genome instability in Streptomyces ambofaciens
More LessGenetic instability in Streptomyces ambofaciens DSM 40697 is correlated with genomic instability characterized by multiple rearrangements (deletions and/or amplifications) occurring in a large unstable region. We have focused on one of the two amplifiable DNA loci which were mapped in this region: the amplifiable unit of DNA locus 6 (AUD6). The nucleotide sequence of one AUD6 fragment of 1·9 kb reveals the presence of two open reading frames (ORF1 and ORF2) on the basis of the typical Streptomyces base composition at each of the three positions within codons. ORF1 shows some similarity with a gene encoding a regulatory protein. The presence of potential genes in this unstable locus was unexpected because deletions occurred with high frequency within this region in the genetic instability-derived mutant strains. However, transcription analyses by S1 nuclease protection experiments on the wild-type strain showed transcription of both ORF1 and ORF2. Moreover, the amplified strain reveals increased transcription of ORF1 but no transcription of ORF2. The amplification therefore results in a switch in transcription. The unstable region of S. ambofaciens DSM 40697 therefore is not a ‘silent’ region because at least some loci are transcribed.
-
-
-
-
Functional and evolutionary implications of a survey of various actinomycetes for homologues of two Streptomyces coelicolor sporulation genes
More LessIn Streptomyces coelicolor A3(2) the whiB and whiG genes are essential for sporulation, their deduced products being a possible transcriptional activator and an RNA polymerase sigma factor, respectively. In a survey of DNA from diverse actinomycetes by Southern blotting, all samples tested hybridized with whiB, but only those representing genera capable of producing sporulating aerial mycelium hybridized with whiG. It is postulated that whiB may play a more intimate role in hyphal fragmentation processes (including sporulation) than whiG. The whiB and whiG homologues (whiB-Stv and whiG-Stv) of Streptoverticillium griseocaneum were cloned and sequenced, and subjected to functional tests in S. coelicolor whiB and whiG mutants. The genes were closely similar, but not identical, to their S. coelicolor counterparts at the DNA and deduced protein levels, and both Stv. griseocarnum gene products could function well in S. coelicolor. However, studies with hybrid transcription units suggested that the promoter region of whiB-Stv is somewhat inefficient in S. coelicolor.
-
-
-
The chromosomal location of genes for elongation factor Tu and ribosomal protein S10 in the cyanobacterium Spirulina platensis provides clues to the ancestral organization of the str and S10 operons in prokaryotes
More LessThe structural gene (rps10) encoding ribosomal protein S10 of the cyanobacterium Spirulina platensis has been localized both on chromosomal DNA and the previously characterized recombinant plasmid pSp7 harbouring the 3′-terminal portion of the gene for elongation factor G (fus) and the gene for elongation factor Tu (tuf). Alignment of the predicted S10 sequence of S. platensis with the homologous sequences from cyanelles, bacteria, archaea and eukarya showed that the cyanobacterial S10 shares a high degree of sequence homology (74% amino acid identity) with the cyanellar protein. Unlike the situation in Escherichia coli, the rps10 gene of S. plantensis is unlinked to the S10 operon genes, being adjacent to the str operon genes. Since a similar organization could be observed in cyanelles of Cyanophora paradoxa and in all archaea so far analysed, this probably represents the ancestral state.
-
-
-
Genetic structure of Neisseria gonorrhoeae populations: a non-clonal pathogen
More LessReproduction by binary fission generates a clonal genetic structure in bacterial populations in the absence of a high rate of recombination. The extent of recombination in natural populations ofNeisseria gonorrhoeae was determined from an analysis of electrophoretically demonstrable allelic variation at structural genes encoding nine enzyme loci in 227 worldwide isolates. No significant linkage disequilibrium was evident in the population, indicating that recombination must be frequent, relative to binary fission. The genetic structure of N. gonorrhoeae was compared with that of Bacillus subtilis from an earlier study. Linkage disequilibrium was less extreme in the N. gonorrhoeae population than in the local population of B. subtilis , in which only modest clonal structure was evident. Thus, N. gonorrhoeae , unlike pathogens so far examined, has a non-clonal population structure. As expected in a freely recombining population, no correlation was found between electrophoretic genotype and serovar or auxotype.
-
-
-
The draTG gene region of Rhodobacter capsulatus is required for post-translational regulation of both the molybdenum and the alternative nitrogenase
More LessSynthetic oligonucleotides, which were designed according to amino acid sequences conserved between Rhodospirillum rubrum and Azospirillum brasilense DraT and DraG, respectively, were used to identify the corresponding genes of Rhodobacter capsulatus. Sequence analysis of a 1904 bp DNA fragment proved the existence of R. capsulatus draT and draG. These two genes were separated by 11 bp only, suggesting that R. capsulatus draT and draG were part of one transcriptional unit. In contrast to R. rubrum, A. brasilense and Azospirillum lipoferum, the R. capsulatus draTG genes were not located upstream of the structural genes of nitrogenase nifHDK but close to the dctP gene at a distance of about 1000 kb from the nifHDK genes. Deletion mutations in the draTG gene region were constructed and introduced into R. capsulatus wild-type and a nifHDK deletion strain. The resulting mutant strains were examined for post-translational regulation of the molybdenum and the alternative nitrogenase in response to ammonia and darkness. Under ‘switch-off’ conditions the modified (ADP-ribosylated) and the non-modified forms of component II of both the molybdenum and the alternative nitrogenase were detected in a draTG wild-type background by immunoblot analysis, whereas only the non-modified forms were present in the draTG deletion strains. Nitrogenase activity in these strains was followed by the acetylene reduction assay. In contrast to the wild-type, draTG mutants were not affected in nitrogenase activity in response to ammonia or darkness. These results demonstrated that the draTG genes are required for post-translational regulation of both the molybdenum and the heterometal-free nitrogenase in R. capsulatus.
-
-
-
Characterization of regulatory mutations causing anaerobic derepression of the sodA gene in Escherichia coli K12: cooperation between cis- and trans-acting regulatory loci
More LessThe genetic loci leading to anaerobic derepression of a sodA::lacZ protein fusion in a UV-generated mutant strain (UV14) of Escherichia coli were identified. The mutant (UV14) was found to harbour two altered loci: one is in the trans-regulatory gene fnr (fumarate nitrate reduction) where leucine-129 was changed to glutamine (fnr14), and the second (sodA14) is in the promoter region (cis) of the sodA gene apparently affecting the binding of the Fur (ferric uptake regulation) protein. Introduction of an fnr − gene into UV14 restored anaerobic repression of sodA::lacZ and restored the ability of the cells to reduce nitrate. However, when either the fnr 14 or the sodA14 mutation was introduced into an otherwise wild-type background, only slight anaerobic derepression of sodA was observed. When both the cis- and trans-acting mutations (i.e. sodA14 and fnr14) were combined simultaneously in an otherwise wild-type background, the specific activity of sodA:: lacZ expression was comparable to that of the original mutant strain (UV14). Furthermore, a genetically confirmed fur fnr double mutant was also similarly derepressed in anaerobic sodA:: lacZ expression. The data presented suggest that the cis-mutation in UV14 (sodA14) affects the Fur-binding site in the sodA promoter, while having no effect on Fnr or Arc mediated repression. Also, a second putative Fnr-binding site that straddles the ribosomal binding-site was identified in the sodA gene.
-
-
-
Isolation, characterization and nucleotide sequence of the Streptococcus mutans lactose-specific Enzyme II (lacE) gene of the PTS and the phospho-β-galactosidase (lacG) gene
More LessThe lacE and lacG genes from Streptococcus mutans have been isolated and characterized, and their nucleotide sequence has been determined. The lacE gene encodes the lactose-specific Enzyme II component of the phosphoenolpyruvate-dependent phosphotransferase system (PTS). The lacG gene encodes the phospho-β-galactosidase which cleaves the lactose phosphate that is formed by the lactose PTS. The S. mutans lacE and lacG genes are located in the same operon as the tagatose genes. S. mutans metabolizes lactose via the tagatose phosphate pathway. The deduced LacE and LacG proteins of S. mutans display high homology with the corresponding proteins from Lactococcus lactis, Staphylococcus aureus and Lactobacillus casei.
-
-
-
Conservation of regulatory and structural genes for a multi-component phenol hydroxylase within phenol-catabolizing bacteria that utilize a meta-cleavage pathway
More LessPseudomonas sp. strain CF600 can degrade phenol and some of its methylated derivatives via a plasmid (pVI150)-encoded pathway. The metabolic route involves hydroxylation by a multi-component phenol hydroxylase and a subsequent meta-cleavage pathway. All 15 structural genes involved are clustered in an operon that is regulated by a divergently transcribed transcriptional activator. The multi-component nature of the phenol hydroxylase is unusual since reactions of this type are usually accomplished by single component flavoproteins. We have isolated and analysed a number of marine bacterial isolates capable of degrading phenol and a range of other aromatic compounds as sole carbon and energy sources. Southern hybridization and enzyme assays were used to compare the catabolic pathways of these strains and of the archetypal phenol-degrader Pseudomonas U, with respect to known catabolic genes encoded by Pseudomonas CF600. All the strains tested that degraded phenol via a mata-cleavage pathway were found to have DNA highly homologous to each of the components of the multi-component phenol hydroxylase. Moreover, DNA of the same strains also strongly hybridized to probes specific for pVI150-encoded meta-pathway genes and the specific regulator of its catabolic operon. These results demonstrate conservation of structural and regulatory genes involved in aromatic catabolism within strains isolated from diverse geographical locations (UK, Norway and USA) and a range of habitats that include activated sludge, sea water and fresh-water mud.
-
-
-
Bacteriophage ϕKP mediated generalized transduction in Erwinia carotovora subspecies carotovora
More LessThe bacteriophage ϕKP is capable of generalized transduction in Erwinia carotovora subspecies carotovora (Ecc) strains SCRI193 and ATCC 39048. ϕKP is a virulent phage containing double stranded DNA of approximately 46 kb. The frequencies of transduction were established for a number of chromosomal markers and plasmid pHCP2, and conditions for transduction optimized after exposure of the phage lysate to UV irradiation.
-
- Immunology
-
-
-
Antigenic and immunogenic differences in lipopolysaccharides of Escherichia coli J5 vaccine strains of different origins
Escherichia coli strain J5 mutants of various origins have often been used as vaccines for induction of crossreactive, cross-protective antibodies directed against the lipopolysaccharide (LPS) core region. The antigenic composition of LPS from J5 strains of different origin, i.e. strains J5(U), J5(UK), J5(2877) and J5(a), was investigated using monoclonal antibodies (mAbs) reactive only with LPS of a given chemotype, i.e. one specific for the incomplete E. coli core of the Re chemotype, a second mAb reactive only with the E. coli R3 complete core, and a third specific for the O-antigen of E. coli serovar O111. The LPS of strains J5(U) and J5(a) is almost exclusively composed of LPS of the Re chemotype, LPS of the J5(UK) strain is composed of Rc LPS and R3 complete core, while LPS of the J5(2877) strain contains Rc, R3 complete core and O-antigen. Growth of the bacteria in medium supplemented with galactose led to increased expression of complete core. The immune responses to the various strains were investigated. Antiserum to the J5 strain expressing the largest amount of R3 core [J5(UK)] had much higher anti-R3 LPS antibody titres compared to antiserum to the other strains. mAb 53, representative of the anti-R3 response to J5 strains containing complete core, bound to those E. coli LPS expressing the R3 core. Thus, the R3 LPS, present in some J5 vaccine strains is at least partially responsible for some of the cross-reactivities exhibited by some anti-J5 antisera. The present findings may explain some of the discrepant outcomes reported for cross-protection studies with J5 antisera, where J5 strains of various origins grown under different culture conditions have been used as vaccines and where LPS or bacteria expressing various core types have been used for challenge.
-
-
-
-
Biological activities of lipoteichoic acid and peptidoglycan–teichoic acid of Bacillus subtilis 168 (Marburg)
To evaluate the suitability of Bacillus subtilis as a production host of heterologous proteins for pharmaceutical purposes, we assessed the biological activity of this bacterium and its major cell envelope components, lipoteichoic acid (LTA) and peptidoglycan-teichoic acid complex (PG-TA) in several eukaryotic effector assays. LTA and PG-TA were found to be non-toxic for mice and guinea-pigs in a short-term toxicity assay. PG-TA was weakly pyrogenic and weakly mitogenic. Both LTA and PG-TA acted as immunologic adjuvants in mice and when injected in mice, also caused an increase in the number of granulocyte-monocyte colony-forming cells in the bone marrow probably via stimulation of production of granulocyte-macrophage colony-stimulating factor.
-
- Pathogenicity And Medical Microbiology
-
-
-
Structural comparison and epitope analysis of outer-membrane protein PIA from strains of Neisseria gonorrhoeae with differing serovar specificities
More LessThe sequences of the por genes, encoding outer-membrane protein PI, have been obtained from a number of strains of Neisseria gonorrhoeae that express PIA molecules with differing serovar specificities. The inferred amino acid sequences of the mature proteins each comprise 308 residues and show considerable homology, with the degree of sequence variation between PIA molecules being considerably less than seen previously with PIB, but more evenly distributed throughout the molecule. The positions of sequence variation are largely confined to the regions predicted to form one of eight surface-exposed loops, suggesting a more widespread distribution of potential antigenic diversity. The deduced amino acid sequences were used to synthesize peptides for epitope mapping experiments. Some epitopes responsible for serovar specificity or recognized by bactericidal monoclonal antibodies could be identified on the basis of their reactivity with simple linear peptides, whilst others recognized conformational epitopes. By comparison of sequence differences with mAb reactivity it was possible to identify regions that appear to contribute to such determinants, including separated regions of the molecule which together were required for the formation of the conformational epitopes. All the epitopes identified lie at or close to the apices of the predicted surface-exposed loops 1, 3, 6 or 8, focusing attention on these regions as accessible targets for immune attack.
-
-
- Physiology And Growth
-
-
-
Dimensional rearrangement of Escherichia coli B/r cells during a nutritional shift-down
More LessIn a search for the mechanism underlying dimensional changes in bacteria, the glucose analogue methyl α-d-glucoside was used to effect a rapid reduction in the mass growth rate of Escherichia coli by competitively inhibiting glucose uptake, a so-called nutritional shift-down. The new steady-state cell mass and volume were reached after 1 h, during which the rate of cell division was maintained; rearrangement of the linear dimensions (cell length, diameter), however, required an additional 2 h and caused an undershoot in cell length, consistent with the view that E. coli is slow to modify its diameter. The results are compared with the overshoot in cell length that occurs following nutritional shift-up.
-
-
-
-
Correlation between the respiration-driven Na+ pump and Na+-dependent amino acid transport in moderately halophilic bacteria
More LessThe effect of Na+ on amino acid uptake by moderately halophilic bacteria was examined using α-aminoisobutyric acid (AIB) as a nonmetabolizable amino acid analogue. Of the eight moderate halophiles investigated, the six Gram-negative bacteria that have a respiration-driven Na+ pump specifically required Na+ for AIB uptake. On the other hand, the two Gram-positive bacteria that have no respiration-driven Na+ pump showed no requirement for Na+ for AIB uptake. Thus, the mode of energy coupling to amino acid transport was quite different between the Gram-negative and Gram-positive moderate halophiles tested: the former, but not the latter, utilized Na+ circulation for the active uptake of AIB.
-
-
-
Activities of the enzymes of the Ehrlich pathway and formation of branched-chain alcohols in Saccharomyces cerevisiae and Candida utilis grown in continuous culture on valine or ammonium as sole nitrogen source
More LessValine aminotransferase, a key enzyme in both biosynthesis and breakdown of branched-chain amino acids, showed consistently higher activity in Candida utilis grown in continuous culture than in Saccharomyces cerevisiae, while pyruvate decarboxylase and alcohol dehydrogenase, the other two enzymes of the Ehrlich pathway of branched-chain alcohol formation, were lower in activity. By spheroplast lysis, it was shown that valine aminotransferase followed the distribution of pyruvate decarboxylase in being located in the cytosol. Replacement of ammonium as nitrogen source by valine during conditions of carbon or nitrogen limitation caused increased specific activities of these three enzymes in S. cerevisiae, but (with one exception) decreased those of C. utilis. Of the metabolites accumulating in the culture medium, little or no ethanol or branched-chain alcohols were present during carbon-limited growth of either organism, but the change to nitrogen limitation resulted in increases in concentration of 20- to 100-fold in pyruvate, acetate and non-pyruvate keto acids as well as the accumulation of branched-chain alcohols in both organisms, and of ethanol, ethyl acetate and glycerol in S. cerevisiae. When valine was the limiting nitrogen source, there was an increase in non-pyruvate keto acids and a 10- to 16-fold increase in 2-methylpropanol. Total branched-chain alcohols formed under nitrogen limitation were 2-fold higher in S. cerevisiae than in C. utilis, irrespective of nitrogen source. Accumulation of branched-chain alcohols, ethanol, acetate and glycerol was also observed during carbon-limited growth of S. cerevisiae with valine as nitrogen source at dilution rates above the critical rate for transition to respirofermentative growth. Less than 70% of the valine carbon metabolized during growth of S. cerevisiae and only 15% of that used during growth of C. utilis was recovered in identified metabolic products. Even allowing for losses by volatilization during aeration, this suggests that a significant amount of the valine is being metabolized by a route or routes other than the Ehrlich pathway, possibly via the action of branched-chain 2-keto acid dehydrogenase. The molar growth yield for the nitrogen source under either carbon or nitrogen limitation was significantly lower for growth on valine than for growth on ammonium, suggesting that breakdown of valine requires more energy. It is evident that not all the enzymes involved in branched-chain amino acid metabolism in yeasts have yet been identified, nor are their interactions properly understood.
-
-
-
Growth and product formation in chemostat and recycling cultures by Aspergillus niger N402 and a glucoamylase overproducing transformant, provided with multiple copies of the glaA gene
Continuous and recycling cultures were carried out with Aspergillus niger N402 wild-type and a glucoamylase overproducing transformant to investigate growth and product formation characteristics. In shake flask cultures, the amount of glucoamylase produced by the transformant was about five times more than by the wild-type strain. In contrast with these results, a twofold overproduction was found in glucose-limited continuous cultures, while no overproduction was found under maltodextrin-limitation. Two regions of specific growth rates could be distinguished, one at specific growth rates lower (domain I) and one at specific growth rates higher than 0.12 h−1 (domain II). In domain I changes in mycelium morphology and conidia formation were observed. It has been concluded that maintenance requirements are dependent on the specific growth rate over the whole range of measured growth rates. The deviation in linearity in the linear equation of substrate utilization, caused by this phenomenon, should be considered when continuous cultures with filamentous fungi are performed. In recycling cultures, xylose as limiting carbon source repressed glucoamylase production very strongly. Under maltodextrin-limitation a fivefold overproduction was found. After about 150 h, the total amount of glucoamylase produced was still increasing, while total amount of product, measured as carbon, remained constant. After this time no increase in the amount of biomass formed was observed. These results suggest autolysis and cryptic growth taking place in a recycling fermenter and cell death rate equalling growth rate.
-
-
-
Periodic selection in longterm continuous-flow cultures of the filamentous fungus Fusarium graminearum
More LessBy monitoring increases and decreases in the proportion of cycloheximide-resistant macroconidia, periodic selection was observed in populations of the filamentous fungus Fusarium graminearum, grown in glucose-limited chemostat cultures. The results indicated that periodic selection of advantageous mutants of F. graminearum occurred at intervals of about 124 h at both high (D = 0·19 h−1, approximately 34 generations) and low (D = 0·06 h−1, approximately 11 generations) dilution rates. Several ‘adaptive’ peaks (each indicating the appearance of an advantageous mutation) were observed before morphological (highly branched) mutants appeared in the populations; these mutants have previously been observed to have a selective advantage over the parental strain. At intervals, macroconidia harvested from the chemostat were used to inoculate plates of non-antibiotic-containing agar medium, and it was possible to monitor periodic selection in the original chemostat culture using second generation macroconidia harvested from these cultures. The proportion of cycloheximide-, potassium chlorate-, and p-fluoro-dl-phenylalanine-resistant macroconidia in these second generation macroconidia changed in a pattern similar to that observed when monitoring the proportion of cycloheximide-resistant macroconidia in the first generation population harvested directly from the chemostat. The experiments demonstrated that populations of filamentous fungi are heterogeneous and that much of this heterogeneity may already be present at the end of batch growth, i.e. before the onset of continuous cultivation.
-
-
-
Effects of cellobiose on cellulose colonization by a mesophilic, cellulolytic Clostridium (strain C401)
More LessWhen cultured on a mixture of cellobiose and cellulose, Clostridium C401 did not initially attach to cellulose but remained in the liquid phase. After cellobiose exhaustion, bacterial cells grew in association with the insoluble cellulose. Carboxymethylcellulase (CMCase) production on Avicel cellulose was four- to fivefold greater than on cellobiose, and cellulose-grown cells adhered to filter paper with an initial adhesion rate about four- to fivefold greater than did cellobiose-grown cells. Using tritiated thymidine incorporation as a measure of growth, it appeared that transfer of strain C401 from cellobiose to cellulose required an adaptation phase. An extracellular cellulase complex was isolated by affinity chromatography. This enzyme system is a multicomponent aggregate (molecular mass above 5 MDa), and yielded two major polypeptide bands by SDS-PAGE having molecular masses of 130 and 70 kDa. Cellobiose strongly inhibited Avicelase activity and slightly inhibited p-nitrophenylcellobiose hydrolysis (pNPCbase), but had no effect on the CMCase activity of the cellulase complex. In addition, polyclonal antibodies, raised against the purified 130 kDa protein inhibited Avicelase activity, but not CMCase and pNPCbase activities.
-
-
-
UV inhibition of the nematode infection process in Arthrobotrys oligospora and Dactylaria candida
More LessThe effects of UV irradiation on infection of nematodes by two nematode-trapping fungi were studied. Five minutes UV irradiation of the fungi caused an inhibition of the infection process in both Arthrobotrys oligospora and Dactylaria candida. After the nematodes were captured, the infection process stopped; the nematodes were still moving at a time when the nematodes in untreated controls were completely digested. The UV-irradiated fungi were still alive and were capable of further growth. After 15 min UV irradiation the number of captured nematodes was also reduced. Inhibition studies with cycloheximide showed differences between the two fungi. The nematodes were still alive 24 h after capture by treated cultures of A. oligospora while the infection process was normally completed by D. candida. There were minor differences in the peptide pattern on a SDS-PAGE gel between proteins from untreated and UV-irradiated mycelia of both fungi. Both the results from inhibition experiments and changes in the peptide pattern after UV irradiation suggest that the target molecules affected by UV irradiation may have been proteins involved in the infection process, and not the DNA. No effect of UV irradiation was observed on molecules that had been suggested previously to be involved in the nematode infection process (toxins, lectins and proteases).
-
- Plant-Microbe Interactions
-
-
-
Growth of the white rust fungus Albugo candida in callus tissue of Brassica juncea
More LessLeaf and stem explants of Brassica juncea cv. Pusa Bold produced callus tissue and plantlets on Murashige and Skoog medium at 18°C. Among the various organs of inflorescences, systemically infected with Albugo candida explants from hypertrophied peduncles and thickened terminal leaves proved suitable for the production of dua cultures of the biotroph and its host, success with the former being better than with the latter. Dual cultures were also established from ovaries, but poorly. Infected callus grew faster than its healthy counterpart. Leaf and sten pieces with rust pustules did not form callus. The dual culture showed abundant coenocytic intercellular mycelium with spherical haustoria within host cells. Infected callus maintained at 15 and 20 °C for 20 to 30 d showed only sporangial chains that remained confined within the callus tissue, whereas callus maintained at 25 and 30 °C contained both sporangia and oospores, like those of A. candida found in naturally infected tissues. The pathoge could be maintained in infected callus tissue for prolonged periods by periodic subculturing and it kept pace with the growth of the callus tissue. Placement of an infected callus in close contact with a healthy one did no result in infection of the latter.
-
-
Volumes and issues
-
Volume 171 (2025)
-
Volume 170 (2024)
-
Volume 169 (2023)
-
Volume 168 (2022)
-
Volume 167 (2021)
-
Volume 166 (2020)
-
Volume 165 (2019)
-
Volume 164 (2018)
-
Volume 163 (2017)
-
Volume 162 (2016)
-
Volume 161 (2015)
-
Volume 160 (2014)
-
Volume 159 (2013)
-
Volume 158 (2012)
-
Volume 157 (2011)
-
Volume 156 (2010)
-
Volume 155 (2009)
-
Volume 154 (2008)
-
Volume 153 (2007)
-
Volume 152 (2006)
-
Volume 151 (2005)
-
Volume 150 (2004)
-
Volume 149 (2003)
-
Volume 148 (2002)
-
Volume 147 (2001)
-
Volume 146 (2000)
-
Volume 145 (1999)
-
Volume 144 (1998)
-
Volume 143 (1997)
-
Volume 142 (1996)
-
Volume 141 (1995)
-
Volume 140 (1994)
-
Volume 139 (1993)
-
Volume 138 (1992)
-
Volume 137 (1991)
-
Volume 136 (1990)
-
Volume 135 (1989)
-
Volume 134 (1988)
-
Volume 133 (1987)
-
Volume 132 (1986)
-
Volume 131 (1985)
-
Volume 130 (1984)
-
Volume 129 (1983)
-
Volume 128 (1982)
-
Volume 127 (1981)
-
Volume 126 (1981)
-
Volume 125 (1981)
-
Volume 124 (1981)
-
Volume 123 (1981)
-
Volume 122 (1981)
-
Volume 121 (1980)
-
Volume 120 (1980)
-
Volume 119 (1980)
-
Volume 118 (1980)
-
Volume 117 (1980)
-
Volume 116 (1980)
-
Volume 115 (1979)
-
Volume 114 (1979)
-
Volume 113 (1979)
-
Volume 112 (1979)
-
Volume 111 (1979)
-
Volume 110 (1979)
-
Volume 109 (1978)
-
Volume 108 (1978)
-
Volume 107 (1978)
-
Volume 106 (1978)
-
Volume 105 (1978)
-
Volume 104 (1978)
-
Volume 103 (1977)
-
Volume 102 (1977)
-
Volume 101 (1977)
-
Volume 100 (1977)
-
Volume 99 (1977)
-
Volume 98 (1977)
-
Volume 97 (1976)
-
Volume 96 (1976)
-
Volume 95 (1976)
-
Volume 94 (1976)
-
Volume 93 (1976)
-
Volume 92 (1976)
-
Volume 91 (1975)
-
Volume 90 (1975)
-
Volume 89 (1975)
-
Volume 88 (1975)
-
Volume 87 (1975)
-
Volume 86 (1975)
-
Volume 85 (1974)
-
Volume 84 (1974)
-
Volume 83 (1974)
-
Volume 82 (1974)
-
Volume 81 (1974)
-
Volume 80 (1974)
-
Volume 79 (1973)
-
Volume 78 (1973)
-
Volume 77 (1973)
-
Volume 76 (1973)
-
Volume 75 (1973)
-
Volume 74 (1973)
-
Volume 73 (1972)
-
Volume 72 (1972)
-
Volume 71 (1972)
-
Volume 70 (1972)
-
Volume 69 (1971)
-
Volume 68 (1971)
-
Volume 67 (1971)
-
Volume 66 (1971)
-
Volume 65 (1971)
-
Volume 64 (1970)
-
Volume 63 (1970)
-
Volume 62 (1970)
-
Volume 61 (1970)
-
Volume 60 (1970)
-
Volume 59 (1969)
-
Volume 58 (1969)
-
Volume 57 (1969)
-
Volume 56 (1969)
-
Volume 55 (1969)
-
Volume 54 (1968)
-
Volume 53 (1968)
-
Volume 52 (1968)
-
Volume 51 (1968)
-
Volume 50 (1968)
-
Volume 49 (1967)
-
Volume 48 (1967)
-
Volume 47 (1967)
-
Volume 46 (1967)
-
Volume 45 (1966)
-
Volume 44 (1966)
-
Volume 43 (1966)
-
Volume 42 (1966)
-
Volume 41 (1965)
-
Volume 40 (1965)
-
Volume 39 (1965)
-
Volume 38 (1965)
-
Volume 37 (1964)
-
Volume 36 (1964)
-
Volume 35 (1964)
-
Volume 34 (1964)
-
Volume 33 (1963)
-
Volume 32 (1963)
-
Volume 31 (1963)
-
Volume 30 (1963)
-
Volume 29 (1962)
-
Volume 28 (1962)
-
Volume 27 (1962)
-
Volume 26 (1961)
-
Volume 25 (1961)
-
Volume 24 (1961)
-
Volume 23 (1960)
-
Volume 22 (1960)
-
Volume 21 (1959)
-
Volume 20 (1959)
-
Volume 19 (1958)
-
Volume 18 (1958)
-
Volume 17 (1957)
-
Volume 16 (1957)
-
Volume 15 (1956)
-
Volume 14 (1956)
-
Volume 13 (1955)
-
Volume 12 (1955)
-
Volume 11 (1954)
-
Volume 10 (1954)
-
Volume 9 (1953)
-
Volume 8 (1953)
-
Volume 7 (1952)
-
Volume 6 (1952)
-
Volume 5 (1951)
-
Volume 4 (1950)
-
Volume 3 (1949)
-
Volume 2 (1948)
-
Volume 1 (1947)
Most Read This Month
