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101.
In this paper we report studies on photosynthetic formation of inorganic pyrophosphate (PPi) in three phototrophic bacteria. Formation of PPi was found in chromatophores from Rhodopseudomonas viridis but not in chromatophores from Rhodopseudomonas blastica and Rhodobacter capsulatus. The maximal rate of PPi synthesis in Rps. viridis was 0.15 mol PPi formed/(min*mol Bacteriochlorophyll) at 23°C. The synthesis of PPi was inhibited by electron transport inhibitors, uncouplers and fluoride, but was insensitive to oligomycin and venturicidin. The steady state rate of PPi synthesis under continuous illumination was about 15% of the steady-state rate of ATP synthesis. The synthesis of PPi after short light flashes was also studied. The yield of PPi after a single 1 ms flash was equivalent to approximately 1 mol PPi/500 mol Bacteriochlorophyll. In Rps. viridis chromatophores, PPi was also found to induce a membrane potential, which was sensitive to carbonyl cyanide p-trifluoromethoxyphenylhydrazone and NaF.Abbreviations BChl
Bacteriochlorophyll
- F0F1-ATPase
Membrane bound proton translocating ATP synthase
- FCCP
Carbonyl cyanide p-trifluoromethoxyphenylhydrazone
- H+-PPase
Membrane bound proton translocating PPi synthase
- TPP+
Tetraphenyl phosphonium ion
- TPB-
Tetraphenyl boron ion
-
Transmembrane electrical potential difference 相似文献
102.
103.
Sebnem O. Erenler Salih Gencer Hikmet Geckil Benjamin C. Stark Dale A. Webster 《Applied Biochemistry and Microbiology》2004,40(3):241-248
The hemoglobins found in unicellular organisms show a great deal of chemical reactivity, protecting cells against oxidative stress, and hence have been implicated in a wider variety of potential functions than those traditionally associated with animal and plant hemoglobins. There are well-documented studies showing that bacteria expressing Vitreoscilla hemoglobin (VHb), the first prokaryotic hemoglobin characterized, have better growth and oxygen uptake rates than their VHb counterparts. Here, the expression of VHb, its effect on the growth and antioxidant enzyme status of cells under different culture conditions was studied by cloning the complete regulatory and coding sequences (vgb) for VHb in Enterobacter aerogenes. Contrary to what has been reported for Escherichia coli, the expression of vgb in E.aerogenes decreased several fold under 10% of atmospheric oxygen (2% oxygen) and its growth was not greatly improved by the presence of VHb. Measured either as viable cells or total cell mass, untransformed E. aerogenes grew better than the recombinant strains. At the late exponential phase, however, the vgb-bearing strain was determined to have a higher cell number and total cell mass than the strain bearing only the plasmid vector with no vgb insert. The VHb expressing strain also had an oxygen uptake rate several fold higher than its counterparts. Given that oxidative stress may occur upon elevated oxygen exposure and be balanced by the action of antioxi-dative compounds, the level of antioxidative response of E. aerogenes expressing VHb was also studied. The VHb expressing strain had substantially (1.5–2.6-fold) higher catalase activity than strains not expressing VHb. Both VHb+ and VHb- strains, however, showed similar levels of superoxide dismutase activity. The activity of both enzymes was also growth phase dependent. Stationary phase cells of all strains showed 2–5-fold higher activity for these enzymes than cells at the exponential phase. 相似文献
104.
Sayli BS 《Biological trace element research》2003,93(1-3):19-29
In order to rule out the possibility of omitting some individuals in the study at field visits described in previous articles,
either because of the reluctance of the subject or because of his appointment elsewhere, fertility and infertility states
of borate workers of the Borax and Acid Plants in Bandirma, Balikesir are given. Balikesir is one of the four provinces with
large borate deposits of Turkey, and Bandirma is 1 of its 19 districts. This county is relatively far away from borate deposits,
and drinking water piped out through the springs has a boron amount between 0.10 and 0.82 ppm B. That the participants are
occupationally exposed to the mineral in essence is therefore conceivable. At the first phase of the investigation, 191 workers
were interviewed, as detailed previously. Among these, there were six infertiles of the primary type with a rate 3.1%. Boron-unrelated
infertile couples among sibs were found to be 2.6–3.6%, and 3.2% for three-generation marriages—none being higher than those
revealed in different sets of controls. In the second stage of work, computerized files of all workers of the facility and
all employees of the general management sharing the same location were checked without an interview. Twenty-four subjects
(3.4%) out of 712 workers were childless versus 2.7% among 108 employees, and 2.2% among 91 workers of a distantly located
sulfuric acid plant of the same complex. The differences were not significant, and these recent findings support the conclusion
already reached almost unambiguously that boron exposure at the present levels does not interfere with human reproduction. 相似文献
105.
In situ non-invasive spectral discrimination between bone cell phenotypes used in tissue engineering
Notingher I Jell G Lohbauer U Salih V Hench LL 《Journal of cellular biochemistry》2004,92(6):1180-1192
Raman micro-spectroscopy was used to discriminate between different types of bone cells commonly used in tissue engineering of bone, with the aim of developing a method of phenotypic identification and classification. Three types of bone cells were analysed: human primary osteoblasts (HOB), retroviral transfected human alveolar bone cells with SV40 large T antigen (SV40 AB), and osteoblast-like human osteosarcoma derived MG63 cell line. Unsupervised principal component analysis (PCA) and linear discriminant analysis (LDA) of the Raman spectra succeeded in discriminating the osteosarcoma derived MG63 cells from the non-tumour cells (HOB and SV40 AB). No significant differences were observed between the Raman spectra of the HOB and SV40 AB cells, confirming the biochemical similarities between the two cell types. Difference spectra between tumour and non-tumour cells suggested that the spectral discrimination is based on the fact that MG63 osteosarcoma derived cells are characterised by lower concentrations of nucleic acids and higher relative concentrations of proteins compared to the non-tumour bone cells. A supervised classification model (LDA) was built and showed high cross-validation sensitivity (100%) and specificity (95%) for discriminating the MG63 cells and the non-tumour cells, with 96% of the cells being correctly classified either as tumour or non-tumour derived cells. This study proves the feasibility of using Raman spectroscopy to identify in situ phenotypic differences in living cells. 相似文献
106.
Pirkko Mäenpää Taina Kallio Paula Mulo Gaza Salih Eva-Mari Aro Esa Tyystjärvi Christer Jansson 《Plant molecular biology》1993,22(1):1-12
Photoinhibition of photosystem II in the cyanobacterium Synechocystis 6803 was followed after site-specific mutagenesis of the D1 polypeptide. Mutations were created in the stromal/cytosolic loop connecting helices D and E. Two mutations E243K and CA1, a deletion of the three glutamates 242–244 and a substitution Q241H, were made in the putative cleavage area of the D1 polypeptide. A third mutation E229D was made in the PEST-like sequence. Mutants and control cells were illuminated and FV/FM was recorded. Compared to the control, the mutants were less photoinhibited. Fluorescence relaxation after a single flash was delayed in CA1. Restoration of FV/FM after photoinhibition in the mutants was totally dependent on protein synthesis while control cells were able to recover partially also when protein synthesis was inhibited. In addition, the protein synthesis-dependent recovery of CA1 was slowed down. Our results indicate a correlation between the mutated amino acids and photoinhibition of photosystem II. 相似文献
107.
108.
Cutler CP Brezillon S Bekir S Sanders IL Hazon N Cramb G 《American journal of physiology. Regulatory, integrative and comparative physiology》2000,279(1):R222-R229
Recent studies on teleost fish have suggested that their genomes have undergone ancient polyploidization events resulting in the duplication of the genome. A duplicate copy of the Na,K-ATPase beta(1)-isoform (called beta(233)) has been identified in the European eel (Anguilla anguilla). The beta(233)-isoform shares high levels of nucleotide (74.8%) and amino acid (69.9%) homology with the eel beta(1)-subunit as well as other vertebrate beta(1)-sequences. Compared with the widely expressed beta(1)-isoform, expression of beta(233)-mRNA is mainly restricted to epithelial tissues. Seawater acclimation induced increases in beta(233)-mRNA levels in kidney, gill, and intestine of migratory "silver" but not the nonmigratory "yellow" adult eels, suggesting that the factors responsible for this upregulation are themselves developmentally regulated. Expression of a variably glycosylated 40- to 52-kDa beta(233)-protein in both gill "chloride" and intestinal epithelial cells suggests that the beta(233)-isoform of Na,K-ATPase may play an important functional role in the major osmoregulatory tissues of euryhaline fish such as the eel. 相似文献
109.
Kufner S Fleischer RP Kroell T Schmid C Zitzelsberger H Salih H de Valle F Treder W Schmetzer HM 《Cancer immunology, immunotherapy : CII》2005,54(10):953-970
Functional dendritic cells (DC) are professional antigen presenting cells (APC) and can be generated in vitro from leukemic cells from acute myeloid leukemia AML patients, giving rise to APC of leukemic origin presenting leukemic antigens (DCleu). We have already shown that DC can be successfully generated from AML and myeloplastic syndromes (MDS) cells in serum-free standard medium (X-vivo + GM-CSF + IL-4 +TNF + FL) in 10–14 days. In this study, we present that DC counts generated from mononuclear cells (MNC) varied between 20% (from 55 MDS samples), 34% (from 100 AML samples) and 25% (from 38 healthy MNC samples) medium. Between 53% and 58% of DC are mature CD83+ DC. DC harvests were highest in monocytoid FAB types (AML-M4/M5, MDS-CMML) and independent from cytogenetic risk groups, demonstrating that DC-based strategies can be applied for patients with all cytogenetic risk groups. Proof of the clonal derivation of DC generated was obtained in five AML and four MDS cases with a combined FISH/immunophenotype analysis (FISH-IPA): The clonal numerical chromosome aberrations of the diseases were regularly codetectable with DC markers; however, not with all clonal cells being convertible to leukemia-derived DCleu (on average, 53% of blasts in AML or MDS). To the contrary, not all DC generated carried the clonal aberration (on average, 51% of DC). In 41 AML and 13 MDS cases with a suitable antigen expression, we could confirm FISH-IPA data by Flow cytometry: although DCleu are regularly detectable, on average only 57% of blasts in AML and 64% of blasts in MDS were converted to DCleu. After coculture with DC in mixed lymphocyte reactions (MLR), autologous T cells from AML and MDS patients proliferate and upregulate costimulatory receptors. The specific lysis of leukemic cells by autologous T cells could be demonstrated in three cases with AML in a Fluorolysis assay. In six cases with only few DCleu or few vital T cells available after the DC/MLR procedure, no lysis of allogeneic or autologous leukemic cells was seen, pointing to the crucial role of both partners in the lysis process. We conclude: (1) the generation of DC is regularly possible in AML and also in MDS under serum-free conditions. (2) Clonal/leukemia-derived DCleu can be regularly generated from MDS and AML-MNC; however, not with all blasts being converted to DCleu and not all DC generated carrying leukemic markers. We recommend to select DCleu for vaccinations or ex vivo T-cell activations to avoid contaminations with non-converted blasts and non-leukemia-derived DC and to improve the harvest of specific, anti-leukemic T cells. DC and DC-primed T cells could provide a practical strategy for the immunotherapy of AML and MDS. 相似文献
110.
Ozcan A Deveci MS Oztas E Dede M Yenen MC Korgun ET Gunhan O 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》2005,27(4):181-186
OBJECTIVE: To investigate the reported increase in the expression of the glucose transporter GLUT-1 in borderline and malignant ovarian epithelial tumors and its relationship to prognosis. STUDY DESIGN: In this study, areas in which immunohistochemical membranous staining with GLUT-1 were most evident were selected, and the proportions of GLUT-1 expression in 46 benign, 11 borderline and 42 malignant cases of ovarian epithelial tumors were determined quantitatively with a computer and Zeiss Vision KS 400 3.0 (G?ttingen, Germany) for Windows (Microsoft, Redmond, Washington, U.S.A.) image analysis. RESULTS: GLUT-1 expression was determined in all borderline tumors (11 of 11) and in 97.6% of malignant tumors (41 of 42). No GLUT-1 expression was observed in benign tumors. The intensity of GLUT-1 staining was lower in borderline tumors than in malignant cases. This was statistically significant (p = 0.005). As differentiation in malignant tumors increased, proportions of GLUT-1 expression showed a relative increase, but this difference was not statistically significant (p = 0.68). CONCLUSION: When GLUT-1 expression in borderline and malignant ovarian epithelial tumors was analyzed against prognosis, no statistically significant difference was identified. Assessment of GLUT-1 expression using the image analysis program was more reliable, with higher reproducibility than in previous studies. 相似文献