The content of fat in carp (Cyprinus carpio) tissue was evaluated throughout one year. The following tissues were evaluated: skeletal muscle, soft roe, hard roe, fat tissue, and hepatopancreas. Respective fatty acids were determined using gas liquid chromatography (GLC). The highest content of valuable polyunsaturated acids, like eicosahexaenoic acid, was found in soft roe and in skeletal muscle during summer, in hepatopancreas during spring, in hard roe during fall. The content of eicosahexaenoic acid in hard roe remains high in all seasons except summer. Saturated fatty acids like palmitic acid and stearic acid do not fluctuate very much throughout the year. The maximum concentration of oleic acid was found in summer. Differences in fatty acid concentration among different carp tissues depended on the living style, but their variation in the same tissue within the year depended on the main fodder of fish.
Elemental sulfur oxidation by ferric iron in Acidithiobacillus ferrooxidans was investigated. The apparent Michaelis constant for ferric iron was 18.6 mM. An absence of anaerobic ferric iron reduction ability was observed in bacteria maintained on elemental sulfur for an extended period of time. Upon transition from ferrous iron to elemental sulfur medium, the cells exhibited similar kinetic characteristics of ferric iron reduction under anaerobic conditions to those of cells that were originally maintained on ferrous iron. Nevertheless, a total loss of anaerobic ferric iron reduction ability after the sixth passage in elemental sulfur medium was demonstrated. The first proteomic screening of total cell lysates of anaerobically incubated bacteria resulted in the detection of 1599 protein spots in the master two-dimensional electrophoresis gel. A set of 59 more abundant and 49 less abundant protein spots that changed their protein abundances in an anaerobiosis-dependent manner was identified and compared to iron- and sulfur-grown cells, respectively. Proteomic analysis detected a significant increase in abundance under anoxic conditions of electron transporters, such as rusticyanin and cytochrome c(552), involved in the ferrous iron oxidation pathway. Therefore we suggest the incorporation of rus-operon encoded proteins in the anaerobic respiration pathway. Two sulfur metabolism proteins were identified, pyridine nucleotide-disulfide oxidoreductase and sulfide-quinone reductase. The important transcription regulator, ferric uptake regulation protein, was anaerobically more abundant. The anaerobic expression of several proteins involved in cell envelope formation indicated a gradual adaptation to elemental sulfur oxidation.
Hydrogen can serve as an electron donor for chemolithotrophic acidophiles, especially in the deep terrestrial subsurface and geothermal ecosystems. Nevertheless, the current knowledge of hydrogen utilization by mesophilic acidophiles is minimal. A multi-omics analysis was applied on Acidithiobacillus ferrooxidans growing on hydrogen, and a respiratory model was proposed. In the model, [NiFe] hydrogenases oxidize hydrogen to two protons and two electrons. The electrons are used to reduce membrane-soluble ubiquinone to ubiquinol. Genetically associated iron-sulfur proteins mediate electron relay from the hydrogenases to the ubiquinone pool. Under aerobic conditions, reduced ubiquinol transfers electrons to either cytochrome aa3 oxidase via cytochrome bc1 complex and cytochrome c4 or the alternate directly to cytochrome bd oxidase, resulting in proton efflux and reduction of oxygen. Under anaerobic conditions, reduced ubiquinol transfers electrons to outer membrane cytochrome c (ferrireductase) via cytochrome bc1 complex and a cascade of electron transporters (cytochrome c4, cytochrome c552, rusticyanin, and high potential iron-sulfur protein), resulting in proton efflux and reduction of ferric iron. The proton gradient generated by hydrogen oxidation maintains the membrane potential and allows the generation of ATP and NADH. These results further clarify the role of extremophiles in biogeochemical processes and their impact on the composition of the deep terrestrial subsurface.
Colicin production in
Escherichia coli
(
E
.
coli
) strains represents an important trait with regard to microbial survival and competition in the complex intestinal environment. A novel colicin type, colicin Z (26.3 kDa), was described as a product of an original producer, extraintestinal
E
.
coli
B1356 strain, isolated from the anorectal abscess of a 17 years-old man. The 4,007 bp plasmid (pColZ) was completely sequenced and colicin Z activity (
cza
) and colicin Z immunity (
czi
) genes were identified. The
cza
and
czi
genes are transcribed in opposite directions and encode for 237 and 151 amino acid-long proteins, respectively. Colicin Z shows a narrow inhibitory spectrum, being active only against enteroinvasive
E
.
coli
(EIEC) and
Shigella
strains via CjrC receptor recognition and CjrB- and ExbB-, ExbD-mediated colicin translocation. All tested EIEC and
Shigella
strains isolated between the years 1958–2010 were sensitive to colicin Z. The lethal effect of colicin Z was found to be directed against cell wall peptidoglycan (PG) resulting in PG degradation, as revealed by experiments with Remazol Brilliant Blue-stained purified peptidoglycans and with MALDI-TOF MS analyses of treated PG. Colicin Z represents a new class of colicins that is structurally and functionally distinct from previously studied colicin types.
Short‐awned (breviaristatum) mutants were induced in the barley varieties Bonus, Foma and Kristina by ionizing radiations (X‐ and γ‐rays, neutrons) and by chemical mutagens (chiefly sulfonates and ethyleneimine) About 260 mutants were isolated and certified in 1953–1972. Of those tested for allelism approximately 140 were distributed into 17 loci represented by 2 to 26 allelic mutants. Two loci have a single allele. The skew distribution of mutants at different loci is evident. Mutation rates and proportions were determined in M2 progenies during four years of screening. Chlorophyll mutations were approximately 25 times more frequent than breviaristatum types. Among the morphological mutants, erectoides, eceriferum and breviaristaturn types were approximately equally common. In general, chemical mutagens were 2–3 times more efficient than radiations in the induction of all kinds of mutation. Differences in detectability of mutant groups depending on parent variety are briefly discussed. A brief phenotypical description of the individual breviaristatum (ari) loci is given, illustrating the pleiotropic effects often found. Mutants in loci ari‐a, ‐c, ‐d, ‐e, which have previously been placed on the chromosome map, may serve as good marker genes. Mutants of loci ari‐1 and ‐m are of some practical interest owing to their stiff short straw and prolific spikes.
In contrast to iron-oxidizing Acidithiobacillus ferrooxidans, A. ferrooxidans from a stationary phase elemental sulfur-oxidizing culture exhibited a lag phase in pyrite oxidation, which is similar to its behaviour during ferrous iron oxidation. The ability of elemental sulfur-oxidizing A. ferrooxidans to immediately oxidize ferrous iron or pyrite without a lag phase was only observed in bacteria obtained from growing cultures with elemental sulfur. However, these cultures that shifted to ferrous iron oxidation showed a low rate of ferrous iron oxidation while no growth was observed. Two-dimensional gel electrophoresis was used for a quantitative proteomic analysis of the adaptation process when bacteria were switched from elemental sulfur to ferrous iron. A comparison of total cell lysates revealed 39 proteins whose increase or decrease in abundance was related to this phenotypic switching. However, only a few proteins were closely related to iron and sulfur metabolism. Reverse-transcription quantitative PCR was used to further characterize the bacterial adaptation process. The expression profiles of selected genes primarily involved in the ferrous iron oxidation indicated that phenotypic switching is a complex process that includes the activation of genes encoding a membrane protein, maturation proteins, electron transport proteins and their regulators.
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