| 1. |
- Ast, Jennifer C, et al.
(författare)
-
Phylogenetic analysis of the lux operon distinguishes two evolutionarily distinct clades of Photobacterium leiognathi.
- 2004
-
Ingår i: Archives of Microbiology. - : Springer Science and Business Media LLC. - 0302-8933 .- 1432-072X. ; 181:5, s. 352-61
-
Tidskriftsartikel (refereegranskat)abstract
- The luminous marine bacterium Photobacterium mandapamensis was synonymized several years ago with Photobacterium leiognathi based on a high degree of phenotypic and genetic similarity. To test the possibility that P. leiognathi as now formulated, however, actually contains two distinct bacterial groups reflecting the earlier identification of P. mandapamensis and P. leiognathi as separate species, we compared P. leiognathi strains isolated from light-organ symbiosis with leiognathid fishes (i.e., ATCC 25521(T), ATCC 25587, lequu.1.1 and lleuc.1.1) with strains from seawater originally described as P. mandapamensis and later synonymized as P. leiognathi (i.e., ATCC 27561(T) and ATCC 33981) and certain strains initially identified as P. leiognathi (i.e., PL-721, PL-741, 554). Analysis of the 16S rRNA and gyrB genes did not resolve distinct clades, affirming a close relationship among these strains. However, strains ATCC 27561(T), ATCC 33981, PL-721, PL-741 and 554 were found to bear a luxF gene in the lux operon ( luxABFE), whereas ATCC 25521(T), ATCC 25587, lequu.1.1 and lleuc.1.1 lack this gene ( luxABE). Phylogenetic analysis of the luxAB(F)E region confirmed this distinction. Furthermore, ATCC 27561(T), ATCC 33981, PL-721, PL-741 and 554 all produced a higher level of luminescence on high-salt medium, as previously described for PL-721, whereas ATCC 25521(T), ATCC 25587, lequu.1.1 and lleuc.1.1 all produced a higher level of luminescence on low-salt medium, a characteristic of P. leiognathi from leiognathid fish light organs. These results demonstrate that P. leiognathi contains two evolutionarily and phenotypically distinct clades, P. leiognathi subsp. leiognathi (strains ATCC 25521(T), ATCC 25587, lequu.1.1 and lleuc.1.1), and P. leiognathi subsp. mandapamensis (strains ATCC 27561(T), ATCC 33981, PL-721, PL-741 and 554).
|
|
| 2. |
- Barker-Astrom, K., et al.
(författare)
-
Chlorosis during nitrogen starvation is altered by carbon dioxide and temperature status and is mediated by the ClpP1 protease in Synechococcus elongatus
- 2005
-
Ingår i: Archives of Microbiology. - : Springer Science and Business Media LLC. - 0302-8933 .- 1432-072X. ; 183:1, s. 66-69
-
Tidskriftsartikel (refereegranskat)abstract
- The interactive effects of inorganic carbon status, temperature and light on chlorosis induced by nitrogen deficiency, and the roles of Clp proteases in this process were investigated. In wild-type cultures grown in high or ambient CO2, following transfer to media lacking combined nitrogen, phycocyanin per cell dropped primarily through dilution of the pigment through cell division, and also suffered variable degrees of net degradation. When grown at high CO2 (5%), chlorophyll (Chl) suffered net degradation to a greater extent than phycocyanin. In marked contrast, growth at ambient CO2 resulted in Chl per cell dropping through dilution. Conditions that drove net Chl degradation in the wild-type resulted in little or no net Chl degradation in a clpPI inactivation mutant, with Chl content dropping largely through growth dilution in the mutant. The chlorotic response of a clpPII inactivation strain was nearly the same as that of wild-type, although phycocyanin degradation may have been slightly accelerated in the former.
|
|
| 3. |
- Braune, Wolfram, et al.
(författare)
-
Phototactic responses in Haematococcus lacustris and its modification by light intensity and the carotenoid biosynthesis inhibitor Norflurazon
- 1990
-
Ingår i: Archives of Microbiology. - 0302-8933 .- 1432-072X. ; 154, s. 448-452
-
Tidskriftsartikel (refereegranskat)abstract
- At fluence rates below 45 W· m-2 cells of the flagellate stage of Haematococcus lacustris react only positively phototactically with a rather high degree of orientation (indicated by r values up to 0.66 with the Rayleigh test). The directedness of orientation decreases with decreasing irradiance. The degree of directedness of the phototactic response depends on the intensity of preirradiation: Low light intensity applied after strong light application results in a dark reaction (low r values), low light given after darkness stimulates a rather high degree of directedness of positive phototaxis. Weak blue light (=483 nm; 0.4 W · m-2) stimulates positive phototactic response, whereas comparable red light (=658 nm; 0.5 W · m-2) does not. Cells which were grown in a medium containing 10-4 M Norflurazon (effective in inhibition of carotenoid biosynthesis) although maintaining motility completely lose the ability to react positively phototactically. The possible role of carotenoids in the phototactic orientation is discussed.
|
|
| 4. |
- Dubey, Mukesh, et al.
(författare)
-
Investigating the compatibility of the biocontrol agent Clonostachys rosea IK726 with prodigiosin-producing Serratia rubidaea S55 and phenazine-producing Pseudomonas chlororaphis ToZa7
- 2016
-
Ingår i: Archives of Microbiology. - : Springer Science and Business Media LLC. - 0302-8933 .- 1432-072X. ; 198, s. 369-377
-
Tidskriftsartikel (refereegranskat)abstract
- This study was carried out to assess the compatibility of the biocontrol fungus Clonostachys rosea IK726 with the phenazine-producing Pseudomonas chlororaphis ToZa7 or with the prodigiosin-producing Serratia rubidaea S55 against Fusarium oxysporum f. sp. radicis-lycopersici. The pathogen was inhibited by both strains in vitro, whereas C. rosea displayed high tolerance to S. rubidaea but not to P. chlororaphis. We hypothesized that this could be attributed to the ATP-binding cassette (ABC) proteins. The results of the reverse transcription quantitative PCR showed an induction of seven genes (abcB1, abcB20, abcB26, abcC12, abcC12, abcG8 and abcG25) from subfamilies B, C and G. In planta experiments showed a significant reduction in foot and root rot on tomato plants inoculated with C. rosea and P. chlororaphis. This study demonstrates the potential for combining different biocontrol agents and suggests an involvement of ABC transporters in secondary metabolite tolerance in C. rosea.
|
|
| 5. |
- Ekelund, Nils, 1956-
(författare)
-
Effects of calcium channel blockers and DCMU on motility and the photophobic response of Gyrodinium dorsum
- 1989
-
Ingår i: Archives of Microbiology. - 0302-8933 .- 1432-072X. ; 151, s. 187-190
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of the calcium channel blockers, verapamil, diltiazem and lanthanum ions and the Ca2+ dependency on motility as well as the photophobic response (stop-response) of Gyrodinium dorsum were studied. At Ca2+ concentrations below 10-3 M, motility was inhibited. La3+ inhibits the stop-response, in contrast to verapamil and diltiazem. The only calcium channel blocker that increased the amount of non-motile cells was verapamil. The results indicate that motility are Ca2+ dependent and that the stop-responses of G. dorsum could be affected by extracellular Ca2+. Effects of the photosythesis inhibitor (DCMU) on the stop-response was also determined. With background light of different wavelength (614, 658 and 686 nm) the stop-response increased. DCMU inhibited this effect of background light. Negative results with the monoclonal antibody Pea-25 directed to phytochrome and the results with DCMU, indicate that the stop-response of G. dorsum is coupled to photosynthesis rather than to a phytochrome-like pigment. Oxygen evolution, but not cell movement, was completely inhibited by 10-6 M DCMU.
|
|
| 6. |
- Ferreira, Daniela, et al.
(författare)
-
Transcription and regulation of the hydrogenase(s) accessory genes, hypFCDEAB, in the cyanobacterium Lyngbya majuscula CCAP 1446/4
- 2007
-
Ingår i: Archives of Microbiology. - : Springer Science and Business Media LLC. - 0302-8933 .- 1432-072X. ; 188:6, s. 609-617
-
Tidskriftsartikel (refereegranskat)abstract
- Lyngbya majuscula CCAP 1446/4 is a filamentous cyanobacterium possessing both an uptake and a bi-directional hydrogenase. The presence of a single copy of the hyp operon in the cyanobacterial genomes suggests that these accessory genes might be responsible for the maturation of both hydrogenases. We investigated the concomitant transcription of hypFCDEAB with the hydrogenases structural genes-hup and hox. RT-PCRs performed with L. majuscula cells grown under different physiological conditions showed a substantial decrease in the relative amount of hupL transcript under non-N-2-fixing conditions. In contrast, no significant differences were observed for the transcript levels of hypFCDEAB in all conditions tested, while minor fluctuations could be discerned for hoxH. Previously, it was demonstrated that the transcriptional regulators NtcA and LexA interact with the promoter regions of hup and hox, respectively, and that putative binding sites for both proteins are present in the hyp promoter of L. majuscula. Therefore, a putative involvement of NtcA and LexA in the regulation of the hyp transcription was investigated. Electrophoretic mobility shift assays resulted in NtcA or LexA-bound retarded fragments, suggesting the involvement of these proteins in the transcriptional regulation of hypFCDEAB.
|
|
| 7. |
- Gustafsson, Mattias, et al.
(författare)
-
Fatty-acid-displaced transcriptional repressor, a conserved regulator of cytochrome P450 102 transcription in Bacillus species
- 2001
-
Ingår i: Archives of Microbiology. - : Springer Science and Business Media LLC. - 0302-8933 .- 1432-072X. ; 176:6, s. 459-464
-
Tidskriftsartikel (refereegranskat)abstract
- Bacillus subtilis strain 168 encodes two flavocytochromes P450, Cyp102A2 and Cyp102A3. The cyp102A3 gene is preceded by, and organized in an operon with, a gene for a transcriptional regulator, encoded by fatR. The paralogous gene, cyp102A2, is most likely transcribed as a mono-cistronic message. We show that fatR encodes a protein that binds to an operator sequence that is present upstream of its own reading frame, thereby repressing the expression of the fatR-cyp102A3 operon. Unsaturated fatty acids and phytanic acid have the capacity to interact with FatR and to abrogate its binding to the operator sequence.
|
|
| 8. |
- Hagemann, Martin, et al.
(författare)
-
Detection of a phage genome carrying a zonula occludens like toxin gene (zot) in clinical isolates of Stenotrophomonas maltophilia.
- 2006
-
Ingår i: Archives of Microbiology. - : Springer Science and Business Media LLC. - 0302-8933 .- 1432-072X. ; 185:6
-
Tidskriftsartikel (refereegranskat)abstract
- During a study of the genetic diversity of Stenotrophomonas strains, we found an autonomous replicating DNA molecule in chromosomal DNA preparations of the clinical Stenotrophomonas maltophilia strain c5. The entire sequence of 6,907 bp of the isolated DNA molecule was determined, which was called phiSMA9. Seven ORFs, which code for proteins with considerable similarity to proteins in databases, were identified in the DNA sequence. The largest ORF shows high sequence similarities to the pI protein of the filamentous phage phiLf, which was later shown to be identical to toxin Zot of Vibrio cholerae. Beside the Zot-like protein, six other proteins with similarities to known phage proteins such as a phage replication protein RstA and phage absorption or coat protein are encoded on phiSMA9, which indicate that this circular DNA molecule represents the replicative form of a linear phage genome. A PCR-based screening showed that only five from the totally investigated 47 Stenotrophomonas strains of clinical and environmental origin harbor these genes. Altogether, we describe the first genome of a phage for the nosocomial pathogen Stenotrophomonas, which contains a Zot toxin like gene and might be regarded as the first Stenotrophomonas virulence factor.
|
|
| 9. |
- Hambraeus, Gustav, et al.
(författare)
-
Escherichia coli RNase E and RNase G cleave a Bacillus subtilis transcript at the same site in a structure-dependent manner
- 2004
-
Ingår i: Archives of Microbiology. - : Springer Science and Business Media LLC. - 0302-8933 .- 1432-072X. ; 181:2, s. 137-143
-
Tidskriftsartikel (refereegranskat)abstract
- The decay of Bacillus subtilis aprE leader-lacZ mRNA was examined in Escherichia coli wild-type and in mutants deficient in RNase E, RNase G, or both. Two versions of the mRNA were studied: the wild-type mRNA, which has a stem-loop at the 5' end, and a mutant mRNA, with a single-stranded 5' end. The half-life of both transcripts was determined by RNase E, the half-life of the mutant transcript being one-third of that of the wild-type transcript. RNase G cleaved both transcripts at a site within an AU-rich sequence in the stem-loop region, but cleavage was much more efficient when the stem-loop was destabilized. RNase E cleaved at the same site, but less efficiently and only in the mutant transcript.
|
|
| 10. |
- Karlsson, Anna, 1969-, et al.
(författare)
-
CO2-dependent fermentation of phenol to acetate, butyrate and benzoate by an anaerobic, pasteurised culture
- 2000
-
Ingår i: Archives of Microbiology. - : Springer Science and Business Media LLC. - 0302-8933 .- 1432-072X. ; 173:5-6, s. 398-402
-
Tidskriftsartikel (refereegranskat)abstract
- Fermentative degradation of phenol was studied using a non-methanogenic, pasteurised enrichment culture containing two morphologically different bacteria. Phenol was fermented to benzoate, acetate and butyrate and their relative occurrence depended on the concentration of hydrogen. Proportionately more benzoate was formed with high initial levels of H2. The influence of P(H2) on the fermentation pattern was studied both in dense cell suspensions and in growing cultures by addition of hydrogen. An increase in growth yield (OD578 was observed, compared to controls, as a consequence of phenol degradation, however, the increase was less in H2-amended treatments, in which most of the phenol ended up as benzoate. The degradation of phenol in the dense cell suspension experiments was dependent on CO2. Benzoate was not degraded when added as a substrate to the growing culture. This is, to our knowledge, the first report concerning the fermentative degradation of phenol to nonaromatic products.
|
|
| 11. |
|
|
| 12. |
- Leganés, Francisco, et al.
(författare)
-
Wide variation in the cyanobacterial complement of presumptive penicillin-binding proteins
- 2005
-
Ingår i: Archives of Microbiology. - New York : Springer. - 0302-8933 .- 1432-072X. ; 184:4, s. 234-248
-
Tidskriftsartikel (refereegranskat)abstract
- A genomic analysis of putative penicillin-binding proteins (PBPs) that are involved in the synthesis of the peptidoglycan layer of the cell wall and are encoded in 12 cyanobacterial genomes was performed in order to help elucidate the role(s) of these proteins in peptidoglycan synthesis, especially during cyanobacterial cellular differentiation. The analysis suggested that the minimum set of PBPs needed to assemble the peptidoglycan layer in cyanobacteria probably does not exceed one bifunctional transpeptidase-transglycosylase Class A high-molecular-weight PBP; two Class B high-molecular-weight PBPs, one of them probably involved in cellular elongation and the other in septum formation; and one low-molecular-weight PBP. The low-molecular-weight PBPs of all of the cyanobacteria analyzed are putative endopeptidases and are encoded by fewer genes than in Escherichia coli. We show that in Anabaena sp. strain PCC 7120, predicted proteins All2981 and Alr4579, like Alr5101, are Class A high-molecular-weight PBPs that are required for the functional differentiation of aerobically diazotrophic heterocysts, indicating that some members of this class of PBPs are required specifically for cellular developmental processes.
|
|
| 13. |
- Lin, Po-Chi, et al.
(författare)
-
NADH oxidation drives respiratory Na+ transport in mitochondria from Yarrowia lipolytica
- 2008
-
Ingår i: Archives of Microbiology. - : Springer Science and Business Media LLC. - 0302-8933 .- 1432-072X. ; 190:4, s. 471-480
-
Tidskriftsartikel (refereegranskat)abstract
- It is generally assumed that respiratory complexes exclusively use protons to energize the inner mitochondrial membrane. Here we show that oxidation of NADH by submitochondrial particles (SMPs) from the yeast Yarrowia lipolytica is coupled to protonophore-resistant Na+ uptake, indicating that a redox-driven, primary Na+ pump is operative in the inner mitochondrial membrane. By purification and reconstitution into proteoliposomes, a respiratory NADH dehydrogenase was identified which coupled NADH-dependent reduction of ubiquinone (1.4 micromol min(-1) mg(-1)) to Na+ translocation (2.0 micromol min(-1) mg(-1)). NADH-driven Na+ transport was sensitive towards rotenone, a specific inhibitor of complex I. We conclude that mitochondria from Y. lipolytica contain a NADH-driven Na+ pump and propose that it represents the complex I of the respiratory chain. Our study indicates that energy conversion by mitochondria does not exclusively rely on the proton motive force but may benefit from the electrochemical Na+ gradient established by complex I.
|
|
| 14. |
- Linder, Tomas
(författare)
-
Evaluation of the chitin-binding dye Congo red as a selection agent for the isolation, classification, and enumeration of ascomycete yeasts
- 2018
-
Ingår i: Archives of Microbiology. - : Springer Science and Business Media LLC. - 0302-8933 .- 1432-072X. ; 200, s. 671-675
-
Tidskriftsartikel (refereegranskat)abstract
- Thirty-nine strains of ascomycete yeasts representing 35 species and 33 genera were tested for their ability to grow on solid agar medium containing increasing concentrations of the chitin-binding dye Congo red. Six strains were classified as hypersensitive (weak or no growth at 10 mg/l Congo red), five were moderately sensitive (weak or no growth at 50 mg/l), three were moderately tolerant (weak or no growth at 100 mg/l), while the remaining 25 strains were classified as resistant (robust growth at >= 100 mg/l) with 20 of these strains classified as hyper-resistant (robust growth at 200 mg/l). Congo red growth phenotypes were consistent within some families but not others. The frequency of Congo red resistance among ascomycete yeasts was deemed too high for the practical use of Congo red as a selection agent for targeted isolation, but can be useful for identification and enumeration of yeasts.
|
|
| 15. |
- Linder, Tomas
(författare)
-
Phenotypical characterisation of a putative -amino acid transaminase in the yeast Scheffersomyces stipitis
- 2019
-
Ingår i: Archives of Microbiology. - : Springer Science and Business Media LLC. - 0302-8933 .- 1432-072X. ; 201, s. 185-192
-
Tidskriftsartikel (refereegranskat)abstract
- Phylogenetic analysis of class III transaminases in the budding yeasts Lachancea kluyveri, Saccharomyces cerevisiae and Scheffersomyces stipitis identified a hitherto uncharacterised Sch. stipitis transaminase encoded by the PICST_54153 gene, which clustered with previously described -amino butyric acid (GABA) and -alanine transaminases. Deletion of the PICST_54153 gene in Sch. stipitis resulted in a complete loss in the utilisation of -alanine and -ureidopropionic acid as nitrogen sources, while growth on 1,3-diaminopropane displayed a significant lag phase compared to the wild-type control. It was therefore concluded that the Sch. stipitis PICST_54153 gene likely encodes a -alanine transaminase. However, minor growth defects when 1,4-diaminobutane or 1,5-diaminopentane was provided as the nitrogen source suggested that the Picst_54153 transaminase may also participate in the catabolism of other diamine-derived -amino acids. Unexpectedly, the picst_54153 deletion mutant failed to grow on solid minimal medium in the presence of 5mM -alanine even if a preferred nitrogen source was provided.
|
|
| 16. |
- Matsson, Mikael, et al.
(författare)
-
Carboxin resistance in Paracoccus denitrificans conferred by a mutation in the membrane-anchor domain of succinate:quinone oxidoreductase (Complex II)
- 1998
-
Ingår i: Archives of Microbiology. - : Springer Science and Business Media LLC. - 0302-8933 .- 1432-072X. ; 170:1, s. 27-37
-
Tidskriftsartikel (refereegranskat)abstract
- Succinate:quinone reductase is a membrane-bound enzyme of the citric acid cycle and the respiratory chain. Carboxin is a potent inhibitor of the enzyme of certain organisms. The bacterium Paracoccus denitrificans was found to be sensitive to carboxin in vivo, and mutants that grow in the presence of 3'-methyl carboxin were isolated. Membranes of the mutants showed resistant succinate:quinone reductase activity. The mutation conferring carboxin resistance was identified in four mutants. They contained the same missense mutation in the sdhD gene, which encodes one of two membrane-intrinsic polypeptides of the succinate:quinone reductase complex. The mutation causes an Asp to Gly replacement at position 89 in the SdhD polypeptide. P. denitrificans strains that overproduced wild-type or mutant enzymes were constructed. Enzymic properties of the purified enzymes were analyzed. The apparent K-m for quinone (DPB) and the sensitivity to thenoyltrifluoroacetone was normal for the carboxin-resistant enzyme, but the succinate:quinone reductase activity was lower than for the wild-type enzyme. Mutations conferring carboxin resistance indicate the region on the enzyme where the inhibitor binds. A previously reported His to Leu replacement close to the [3Fe-4S] cluster in the iron-sulfur protein of Ustilago maydis succinate:quinone reductase confers resistance to carboxin and thenoyltrifluoroacetone. The Asp to Gly replacement in the P. denitrificans SdhD polypeptide, identified in this study to confer resistance to carboxin but not to thenoyltrifluoroacetone, is in a predicted cytoplasmic loop connecting two transmembrane segments. It is likely that this loop is located in the neighborhood of the [3Fe-4S] cluster.
|
|
| 17. |
- Metsäniitty, Marjut, et al.
(författare)
-
Extracellular vesicles from Aggregatibacter actinomycetemcomitans exhibit potential antitumorigenic effects in oral cancer : a comparative in vitro study
- 2024
-
Ingår i: Archives of Microbiology. - : Springer Nature. - 0302-8933 .- 1432-072X. ; 206:6
-
Tidskriftsartikel (refereegranskat)abstract
- Aggregatibacter actinomycetemcomitans is an opportunistic Gram-negative periodontopathogen strongly associated with periodontitis and infective endocarditis. Recent evidence suggests that periodontopathogens can influence the initiation and progression of oral squamous cell carcinoma (OSCC). Herein we aimed to investigate the effect of A. actinomycetemcomitans-derived extracellular vesicles (EVs) on OSCC cell behavior compared with EVs from periodontopathogens known to associate with carcinogenesis. EVs were isolated from: A. actinomycetemcomitans and its mutant strains lacking the cytolethal distending toxin (CDT) or lipopolysaccharide (LPS) O-antigen; Porphyromonas gingivalis; Fusobacterium nucleatum; and Parvimonas micra. The effect of EVs on primary and metastatic OSCC cells was assessed using cell proliferation, apoptosis, migration, invasion, and tubulogenesis assays. A. actinomycetemcomitans-derived EVs reduced the metastatic cancer cell proliferation, invasion, tubulogenesis, and increased apoptosis, mostly in CDT- and LPS O-antigen-dependent manner. EVs from F. nucleatum impaired the metastatic cancer cell proliferation and induced the apoptosis rates in all OSCC cell lines. EVs enhanced cancer cell migration regardless of bacterial species. In sum, this is the first study demonstrating the influence of A. actinomycetemcomitans-derived EVs on oral cancer in comparison with other periodontopathogens. Our findings revealed a potential antitumorigenic effect of these EVs on metastatic OSCC cells, which warrants further in vivo investigations.
|
|
| 18. |
|
|
| 19. |
|
|
| 20. |
- Proenca, Audrey Menegaz, et al.
(författare)
-
Genomic, biochemical, and phylogenetic evaluation of bacteria isolated from deep-sea sediment harboring methane hydrates
- 2022
-
Ingår i: Archives of Microbiology. - : Springer. - 0302-8933 .- 1432-072X. ; 204:4
-
Tidskriftsartikel (refereegranskat)abstract
- Over half of the organic carbon on Earth's surface is trapped in marine sediment as methane hydrates. Ocean warming causes hydrate dissociation and methane leakage to the water column, rendering the characterization of microbes from hydrate depositions a pressing matter. Through genomic, phylogenetic, and biochemical assays, we characterize the first microorganisms isolated from the Rio Grande Cone (Brazil), reservoir responsible for massive methane releases to the water column. From sediment harboring rich benthic communities, we obtained 43 strains of Brevibacillus sp., Paenibacillus sp. and groups of Bacillus sp. Methane-enriched samples yielded strains of the Pseudomonas fluorescens complex, exhibiting fluorescent siderophore production and broad multi-carbon catabolism. Genomic characterization of a novel Pseudomonas sp. strain indicated 32 genes not identified in the closest related type-species, including proteins involved with mercury resistance. Our results provide phylogenetic and genomic insights on the first bacterial isolates retrieved from a poorly explored region of the South Atlantic Ocean.
|
|
| 21. |
|
|
| 22. |
- Samanta, Loknath, et al.
(författare)
-
Differential catalase activity and tolerance to hydrogen peroxide in the filamentous cyanobacteria Nostoc punctiforme ATCC 29113 and Anabaena sp. PCC 7120
- 2022
-
Ingår i: Archives of Microbiology. - : Springer Nature. - 0302-8933 .- 1432-072X. ; 204
-
Tidskriftsartikel (refereegranskat)abstract
- Photoautotrophic cyanobacteria often confront hydrogen peroxide (H2O2), a reactive oxygen species potentially toxic to cells when present in sufficiently high concentrations. In this study, H2O2 tolerance ability of filamentous cyanobacteria Nostoc punctiforme ATCC 29133 (Nostoc 29133) and Anabaena sp. PCC 7120 (Anabaena 7120) was investigated at increasing concentrations of H2O2 (0-0.5 mM). In Nostoc 29133, 0.25 and 0.5 mM H2O2 caused a reduction in chlorophyll a content by 12 and 20%, respectively, whereas with similar treatments, a total loss of chlorophyll a was detected in Anabaena 7120. Further, Nostoc 29133 was able to maintain its photosystem II performance in the presence of H2O2 up to a concentration of 0.5 mM, whereas in Anabaena 7120, 0.25 mM H2O2 caused a complete reduction of photosystem II performance. The intracellular hydroperoxide level (indicator of oxidative status) did not increase to the same high level in Nostoc 29133, as compared to in Anabaena 7120 after H2O2 treatment. This might be explained by that Nostoc 29133 showed a 20-fold higher intrinsic constitutive catalase activity than Anabaena 7120, thus indicating that the superior tolerance of Nostoc 29133 to H2O2 stems from its higher ability to decompose H2O2. It is suggested that difference in H2O2 tolerance between closely related filamentous cyanobacteria, as revealed in this study, may be taken into account for judicious selection and effective use of strains in biotechnological applications.
|
|
| 23. |
- Selstam, Eva, 1945-, et al.
(författare)
-
Membrane lipid composition of the unusual cyanobacterium Gloeobacter violaceus sp PCC 7421, which lacks sulfoquinovosyl diacylglycerol
- 1996
-
Ingår i: Archives of Microbiology. - 0302-8933 .- 1432-072X. ; 166:2, s. 132-135
-
Tidskriftsartikel (refereegranskat)abstract
- Gloeobacter violaceus sp. PCC 7421 is an unusual cyanobacterium with only one cellular membrane, which lacks the thylakoid membranes found in other oxygenic photosynthetic organisms. The cell membrane lipids in G. violaceus sp. PCC 7421 are monogalactosyl diacylglycerol, digalactosyl diacylglycerol, phosphatidyl glycerol and phosphatidic acid in the molar proportion of 51, 24, 18 and 4% respectively. This lipid composition resembles that of the cell membrane from other cyanobacteria, but completely lacks sulfoquinovosyl diacylglycerol. This lack of sulfoquinovosyl diacylglycerol is exceptional for a photosynthetic membrane. The membrane lipids are esterified to 14:0, 16:0, 16:1, 18:0, 18:1, 18:2 and alpha 18:3 fatty acids.
|
|
| 24. |
- Sharma, Tanuj, et al.
(författare)
-
Identifying novel inhibitors targeting Exportin-1 for the potential treatment of COVID-19
- 2024
-
Ingår i: ARCHIVES OF MICROBIOLOGY. - 0302-8933 .- 1432-072X. ; 206:2
-
Tidskriftsartikel (refereegranskat)abstract
- The nuclear export protein 1 (XPO1) mediates the nucleocytoplasmic transport of proteins and ribonucleic acids (RNAs) and plays a prominent role in maintaining cellular homeostasis. XPO1 has emerged as a promising therapeutic approach to interfere with the lifecycle of many viruses. In our earlier study, we proved the inhibition of XPO1 as a therapeutic strategy for managing SARS-COV-2 and its variants. In this study, we have utilized pharmacophore-assisted computational methods to identify prominent XPO1 inhibitors. After several layers of screening, a few molecules were shortlisted for further experimental validation on the in vitro SARS-CoV-2 cell infection model. It was observed that these compounds reduced spike positivity, suggesting inhibition of SARS-COV-2 infection. The outcome of this study could be considered further for developing novel antiviral therapeutic strategies against SARS-CoV-2.
|
|
| 25. |
- Sirijovski, Nick, et al.
(författare)
-
Rhodobacter capsulatus magnesium chelatase subunit BchH contains an oxygen sensitive iron-sulfur cluster
- 2007
-
Ingår i: Archives of Microbiology. - : Springer Science and Business Media LLC. - 0302-8933 .- 1432-072X. ; 188:6, s. 599-608
-
Tidskriftsartikel (refereegranskat)abstract
- Magnesium chelatase is the first unique enzyme of the bacteriochlorophyll biosynthetic pathway. It consists of three subunits (BchI, BchD, and BchH). Amino acid sequence analysis of the Rhodobacter capsulatus BchH revealed a novel cysteine motif ((393)CX(2)CX(3)CX(14)C) that was found in only six other proteobacteria (CX(2)CX(3)CX(11-14)C). The cysteine motif is likely to coordinate an unprecedented [Fe-S] cluster. Purified BchH demonstrated absorbance in the 460 nm region. This absorbance was abolished in BchH proteins with alanine substitutions at positions Cys396 and Cys414. These modified proteins were also EPR silent. In contrast, wild type BchH protein in the reduced state showed EPR signals resembling those of a [4Fe-4S] cluster with rhombic symmetry and g values at 1.90, 1.93, and 2.09, superimposed with a [3Fe-4S] cluster centered at g = 2.02. The [3Fe-4S] signal was observed independently of the [4Fe-4S] signal under oxidizing conditions. Mg-chelatase activity assays showed that the cluster is not catalytic. We suggest that the [4Fe-4S] and [3Fe-4S] signals originate from a single coordination site on the monomeric BchH protein and that the [4Fe-4S] cluster is sensitive to oxidation. It is speculated that the cluster participates in the switching between aerobic and anaerobic life of the proteobacteria.
|
|
| 26. |
- Strandberg, Rebecka, 1982-, et al.
(författare)
-
Coexistence and expression profiles of two alternative splice variants of the pheromone receptor gene pre-1 in Neurospora crassa
- 2013
-
Ingår i: Archives of Microbiology. - : Springer Science and Business Media LLC. - 0302-8933 .- 1432-072X. ; 195:10-11, s. 773-780
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, we show that two splice variants of the pheromone receptor gene (pre-1) transcript coexist in vegetative and reproductive tissues of the filamentous ascomycete fungus Neurospora crassa. The two splice variants differ by intron retention of the last intron, which is predicted to result in a premature stop codon and loss of 322 amino acids in the C-terminal cytosolic region of PRE-1. Using quantitative PCR, we show that expression of the variants is influenced by mating type (mat), with a higher proportion of intron-spliced transcripts in a mat A strain and a higher proportion of the intron-retained variant in a mat a strain. The intron-retained PRE-1 variant is predicted to lack 6 ubiquitination sites that may influence receptor function. In conclusion, N. crassa produce two pre-1 splice variants that display different transcription profiles.
|
|
| 27. |
- Tzelepis, Georgios, et al.
(författare)
-
Detection of Verticillium species in Swedish soils using real‑time PCR
- 2017
-
Ingår i: Archives of Microbiology. - : Springer Science and Business Media LLC. - 0302-8933 .- 1432-072X. ; 199, s. 1383-1389
-
Tidskriftsartikel (refereegranskat)abstract
- Verticillium species are soilborne plant pathogens, responsible for big yield losses worldwide. Here, we report improved procedures to generate DNA from Verticillium species imbedded in farm soils. Using new genomic sequence information, primers for V. dahliae, V. albo-atrum, V. tricorpus, and V. longisporum were designed. In a survey of 429 samples from intensively farmed soil of two Swedish regions, only V. dahliae and V. longisporum were identified. A bias towards V. longisporum (40%) was seen in the south, whereas V. dahliae was more frequent in the western region (19%). Analyses of soil and leaf samples from 20 sugar beet fields, where foliar wilting had been observed, revealed V. dahliae DNA in all leaf and soil samples and V. longisporum in 18 soil samples, illustrating host choice and longevity of the V. longisporum microsclerotia. This study demonstrates the applicability of new molecular diagnostic tools that are important for growers of variable crops.
|
|
| 28. |
- Wegrzyn, A., et al.
(författare)
-
ClpP/ClpX-mediated degradation of the bacteriophage lambda O protein and regulation of lambda phage and lambda plasmid replication
- 2000
-
Ingår i: Archives of Microbiology. - : Springer Science and Business Media LLC. - 0302-8933 .- 1432-072X. ; 174:02-jan, s. 89-96
-
Tidskriftsartikel (refereegranskat)abstract
- The O protein is a replication initiator that binds to the ori lambda region and promotes assembly of the bacteriophage lambda replication complex. This protein, although protected from proteases by other elements of the replication complex, in a free form is rapidly degraded in the host, Escherichia coil, by the ClpP/ClpX protease. Nevertheless, the physiological role of this rapid degradation remains unclear. Here we demonstrate that the copy number of plasmids derived from bacteriophage lambda is significantly higher in wild-type cells growing in rich media than in slowly growing bacteria. However, lambda plasmid copy number in bacteria devoid of the ClpP/ClpX protease was not dependent on the bacterial growth rate and in all minimal media rested was comparable to that observed in wildtype cells growing in a rich medium. Contrary to lambda plasmid replication, the efficiency of lytic growth of bacteriophage lambda was found to be dependent on the host growth rate in both wild-type bacteria and clpP and clpX mutants. The activities of two major lambda promoters operating during the lytic development, p(R) and p(L), were found to be slightly dependent on the host growth rate. However, when p(R) activity was significantly decreased in the dnaA mutant, production of phage progeny was completely abolished at low growth rates. These results indicate that the O protein (whose level in E. coli cells depends on the activity of ClpP/ClpX protease) is a major limiting factor in the regulation of lambda plasmid replication at low bacterial growth rates. However, this protein seems to be only one of the limiting factors in the bacteriophage lambda lytic development under poor growth conditions of host cells. Therefore, it seems that the role of the rapid ClpP/ClpX-mediated proteolysis of the O protein is to decrease the efficiency of early DNA replication of the phage in slowly growing host cells.
|
|
| 29. |
- Ascencio, F, et al.
(författare)
-
Cell-surface charge and cell-surface hydrophobicity of collagen-binding Aeromonas and Vibrio strains
- 1995
-
Ingår i: Archives of Microbiology. - 0302-8933. ; 164:3, s. 223-230
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract Partitioning in aqueous polymer two-phase systems of polyethylene glycol and dextran was used to detect and compare cell-surface charge and cell-surface hydrophobicity of Aeromonas hydrophila, A. caviae, A. sobria, Vibrio cholerae, and V. anguillarum strains. These strains have cell-surface components that bound either native or thermally denatured type I collagen (i.e., a mixture of the alpha1+alpha2 chains) and gelatin immobilized on latex beads. Our goals were: (1) to compare the possible relationship between the cell-surface charge/hydrophobicity and binding to collagen and (2) to evaluate the influence of the culture media on the expression of surface properties. There was no apparent relationship between cell-surface charge, cell-surface hydrophobicity, and binding to collagen. The expression of surface properties was dependent on the culture media. There was no relationship between binding to immobilized collagen and binding to soluble 125I-labeled collagen. Particle-agglutination reactivity differed when using various collagen-coated microbead preparations. There were general differences in the particle-agglutination reactivity when collagen-coated latex beads were prepared using different coating procedures. The negative charge and hydrophobicity of the various collagen-coated microbead preparations were also studied by partitioning in the two-phase system of polyethylene glycol and dextran. Under these conditions, the alpha1+alpha2 collagen-chain mixture covalently immobilized on carboxy-modified latex beads was less hydrophobic and negatively charged than gelatin and native collagen immobilized on the same kind of latex beads. For latex beads passively coated with collagen preparations, the alpha1+alpha2 collagen-chain mixture was more hydrophobic than gelatin and native collagen. We suggest that for screening collagen-binding among Vibrio and Aeromonas strains, a reliable and sensitive particle-agglutination assay should consider the collagen preparation and the coating procedure for the immobilization of collagen onto the latex beads. In this regard, carboxy-modified latex beads coated with an alpha1+alpha2 collagen-chain mixture gave the best results.
|
|
| 30. |
|
|
| 31. |
|
|
| 32. |
- Malmcrona-Friberg, Karin, et al.
(författare)
-
Chemical changes in cell envelope and poly-β-hydroxybutyrate during short term starvation of a marine bacterial isolate
- 1986
-
Ingår i: Archives of Microbiology. - 0302-8933. ; 144:4, s. 340-345
-
Tidskriftsartikel (refereegranskat)abstract
- Qualitative and quantitative changes were observed in lipids, poly-β-hydroxybutyrate (PHB), and a cell wall peptidoglycan consitutent in a marine bacterial isolate during starvation for 24 h in an energy and nutrient-free medium. While the amount and composition of the membrane fatty acids fluctuated within the first hours of starvation, the total amount of fatty acids decreased during the starvation period. Furthermore, the ratio of monounsaturated to saturated fatty acids decreased and the proportion of short chain fatty acids increased. In the very early phase of starvation the bacteria contained PHB, which had been accumulated during the growth phase, but after 3 h no PHB was detected. Cells starved for phosphorus showed a different pattern as PHB was initially accumulated and did not decrease until 5 h of starvation. Synthesis of the cell wall amino acid d-alanine was initiated during the first phase of starvation. The effects of these changes on membrane fluidity and uptake of substrates as well as the use of fatty acids and PHB as energy resources during starvation are discussed.
|
|
| 33. |
- Mårdén, Per, et al.
(författare)
-
Physiological and morphological changes during short term starvation of marine bacterial islates
- 1985
-
Ingår i: Archives of Microbiology. - 0302-8933. ; 142:4, s. 326-332
-
Tidskriftsartikel (refereegranskat)abstract
- Three marine bacteria were examined for physiological and morphological changes in the initial phase of starvation. It was found that the starvation process was induced in a similar way irrespective of whether the cells were suspended in nutrient and energy free artificial seawater (NSS) or NSS supplemented with nitrogen and phosphorus. An initial phase of increased activity was consistent with a decreased response to added nutrients. Recovery from starvation exhibited the same response in both these starvation regimes, measured throughout the starvation period. Cells in nitrogen or phosphorus deprived starvation regimes, showed a high and rapid increased activity, followed by a delayed and more pronounced decline in respiratory activity. The initial phase of starvation also included a loss of poly-β-hydroybutyrate as observed by transmission electron microscopy (TEM). Two bacterial strains showed formation of small vesicles on the outer cell layer when examined by TEM. This formation and release of vesicles was related to the continuous size reduction during starvation survival. The results are discussed in terms of defining the mechanisms of initial cellular responses to nutrient deprivation.
|
|
| 34. |
- Valeur, Anders, et al.
(författare)
-
Differences in lipid composition between free-living and initially adhered cells of a Gram-negative bacterium
- 1988
-
Ingår i: Archives of Microbiology. - 0302-8933. ; 149:6, s. 521-526
-
Tidskriftsartikel (refereegranskat)abstract
- The phospholipid fatty acid composition and poly-β-hydroxybutyrate (PHB) content of initially adhered and free-living cells of a Pseudomonas sp. isolated from the rape plant Brassica napus were examined with gas chromatography (GC). Five different adhesion experiments were made including variations in surface charge (hydrophilic and lipophilic), temperature, media composition and time of adhesion. Lipids and poly-β-hydroxybutyrate (PHB) were extracted with a chloroform-methanol-water mixture, hydrolyzed and esterified with pentafluorobenzyl bromide. Analysis was performed with capillary gas chromatography and flame ionization detection. A pronounced difference in both the ratio saturated/unsaturated fatty acids and in PHB content between free-living and adhered bacteria were found. The free-living bacteria has a significantly smaller ratio of saturated/unsaturated C16 and C18 fatty acids and also a smaller ratio of total C18/total C16 fatty acids. Bacteria adhered to the lipophilic surface had a higher ratio of saturated to unsaturated C16 fatty acids than at the hydrophilic surface. There were no major differences between the treatments regarding the amount of bacteria adhered to the surface or their lipid composition.
|
|
| 35. |
- Jiang, Fangyuan, et al.
(författare)
-
Improved Object Detection and Pose Using Part-Based Models
- 2013
-
Ingår i: Lecture Notes in Computer Science (Image Analysis : 18th Scandinavian Conference, SCIA 2013, Espoo, Finland, June 17-20, 2013. Proceedings). - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. - 9783642388859 - 9783642388866 ; 7944, s. 396-407
-
Konferensbidrag (refereegranskat)abstract
- Automated object detection is perhaps the most central task of computer vision and arguably the most difficult one. This paper extends previous work on part-based models by using accurate geometric models both in the learning phase and at detection. In the learning phase manual annotations are used to reduce perspective distortion before learning the part-based models. That training is performed on rectified images, leads to models which are more specific, reducing the risk of false positives. At the same time a set of representative object poses are learnt. These are used at detection to remove perspective distortion. The method is evaluated on the bus category of the Pascal dataset with promising results.
|
|
