scholarly journals Comparison of Cellular and Biomass Specific Activities of Dominant Bacterioplankton Groups in Stratified Waters of the Celtic Sea

2001 ◽  
Vol 67 (11) ◽  
pp. 5210-5218 ◽  
Author(s):  
Mikhail V. Zubkov ◽  
Bernhard M. Fuchs ◽  
Peter H. Burkill ◽  
Rudolf Amann
Keyword(s):  
Protein Synthesis ◽  
Cellular Protein ◽  
Light Scatter ◽  
Flow Sorting ◽  
Sorting Technique ◽  
Specific Activities ◽  
Celtic Sea ◽  
Metabolic Activities

ABSTRACT A flow-sorting technique was developed to determine unperturbed metabolic activities of phylogenetically characterized bacterioplankton groups with incorporation rates of [35S]methionine tracer. According to fluorescence in situ hybridization with rRNA targeted oligonucleotide probes, a clade of α-proteobacteria, related to Roseobacter spp., and aCytophaga-Flavobacterium cluster dominated the different groups. Cytometric characterization revealed both these groups to have high DNA (HNA) content, while the α-proteobacteria exhibited high light scatter (hs) and the Cytophaga-Flavobacteriumcluster exhibited low light scatter (ls). A third abundant group with low DNA (LNA) content contained cells from a SAR86 cluster of γ-proteobacteria. Cellular specific activities of the HNA-hs group were 4- and 1.7-fold higher than the activities in the HNA-ls and LNA groups, respectively. However, the higher cellular protein synthesis by the HNA-hs could simply be explained by their maintenance of a larger cellular protein biomass. Similar biomass specific activities of the different groups strongly support the main assumption that underlies the determination of bacterial production: different bacteria in a complex community incorporate amino acids at a rate proportional to their protein synthesis. The fact that the highest growth-specific rates were determined for the smallest cells of the LNA group can explain the dominance of this group in nutrient-limited waters. The metabolic activities of the three groups accounted for almost the total bacterioplankton activity, indicating their key biogeochemical role in the planktonic ecosystem of the Celtic Sea.

Determination of protein synthesis in human rectal cancer in situ by continuous [1-13C]leucine infusion

1997 ◽  
Vol 272 (5) ◽  
pp. E796-E802 ◽  
Author(s):  
W. H. Hartl ◽  
H. Demmelmair ◽  
K. W. Jauch ◽  
H. L. Schmidt ◽  
B. Koletzko ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Rectal Cancer ◽  
Protein Synthesis ◽  
Tumor Tissue ◽  
Normal Mucosa ◽  
Constant Infusion ◽  
Precursor Pool ◽  
Arterial Blood

Previous studies on human colorectal tumor protein synthesis in situ relied on techniques that required intra- or perioperative sampling to obtain a sufficient biopsy size. The purpose of the present study was to develop a new technique by use of new mass spectrometry equipment [capillary gas chromatography (GC)-combustion isotope ratio mass spectrometry (IRMS)], which allows reduction of the necessary sampling size. Thereby, tumor sampling could be done via conventional rectosigmoidoscopy, excluding the need for further disturbing invasive measures. Fifteen postabsorptive patients with localized rectal cancer received a primed-constant infusion of [1-13C]leucine (0.16 mumol.kg-1.min-1 constant, 9.6 mumol/kg prime). Forceps biopsies were taken after 3 and 6 h. In five subjects, tumor tissue and normal mucosa were studied simultaneously. Determination of protein-bound leucine enrichment was done by GC-IRMS, and GC-quadrupole MS was used to determine tracer-to-tracee ratios (tracer/tracee) for free intracellular leucine. GC-MS data demonstrated achievement of a steady state in the precursor pool enrichment after 3 h of isotope infusion (tracer/tracee at 3 h: 6.34 +/- 0.46%, at 6 h: 6.58 +/- 0.38%). Calculation of tumor protein synthesis yielded a fractional synthetic rate (FSR) of 1.06 +/- 0.11%/h or 25.5 +/- 2.6%/day (range 12.0-37.1%/day). At any time, protein-bound leucine enrichment was significantly higher in tumor tissue than in normal mucosa of the same subject. However, protein synthetic rates were comparable (tumor: 1.09 +/- 0.20%/h, mucosa: 1.29 +/- 0.28%/h). Thus combined GC-combustion IRMS and GC-/quadrupole MS provide a simple, reliable, and minimally invasive method to determine tumor FSR in situ, thereby excluding interferences common to previous methods. Tumor and mucosa tissues are similar with respect to protein synthesis, but they apparently differ with respect to leucine extraction from the arterial blood.

Nucleic acid and protein synthesis and pattern regulation in hydra

Development ◽  
1969 ◽  
Vol 21 (1) ◽  
pp. 55-70
Author(s):  
S. G. Clarkson
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Experimental Approach ◽  
Direct Evidence ◽  
Animal Cells ◽  
Rna And Protein Synthesis ◽  
Metabolic Activities ◽  
Time Required ◽  
Pattern Regulation

In a previous paper (Clarkson, 1969) data were presented which indicate that hypostome determination is accompanied by a large and rapid burst of RNA synthesis, a slight stimulation of protein synthesis, and no increase in DNA synthesis. More direct evidence concerning the relative importance of these metabolic activities in hypostome determination is reported in this paper. The experimental approach made use of the transplantation test of Webster & Wolpert (1966) in conjunction with some inhibitors of DNA, RNA and protein synthesis, the rationale being that if these metabolic activities play important roles in the determination of the hypostome, then their inhibition would be expected to have severe effects on the time required for this process. Regarding the inhibitors, hydroxyurea (HU) inhibits DNA synthesis in a variety of animal cells without altering rates of formation of RNA or protein (Young & Hodas, 1964; Yarbro, Kennedy & Barnum, 1965; Schwartz, Garofalo, Sternberg & Philips, 1965).

ATP and Protein Synthesis Assays to Evaluate the Toxicities of Preservatives in Vitro

1991 ◽  
Vol 19 (1) ◽  
pp. 60-67
Author(s):  
Corrado L. Galli ◽  
Barbara Viviani ◽  
Giampiero Casartelli ◽  
Marina Marinovich
Keyword(s):  
Protein Synthesis ◽  
Protein Content ◽  
Cellular Protein ◽  
Cell Protein ◽  
Leucine Incorporation ◽  
Maximal Effect ◽  
Atp Level ◽  
Cellular Protein Content

Cellular protein content, protein synthesis, ATP level and lactate dehydrogenase (LDH) activity, measured in a murine epidermal cell line (HEL/30), were used as the endpoints for determining the cytotoxicities of 17 antimicrobial chemicals. The relative toxicities of the test compounds were quantified by the determination of the concentrations inducing a 50% inhibition of [3H]-leucine incorporation into proteins (IC50), causing a 50% reduction of ATP level or final cell protein content or producing the maximal effect on LDH leakage (EC50) after 2 hours of treatment. The results indicate a good correlation between both the reduction of ATP level and inhibition of protein synthesis and the minimal inhibitory concentration (MIC) on different microorganisms, suggesting that ATP and protein synthesis assays could be useful as prescreening methods for testing the cytotoxicities of preservatives.

Altered protein synthesis during in situ oat leaf senescence

1990 ◽  
Vol 80 (4) ◽  
pp. 619-623 ◽  
Author(s):  
Louise Lalonde ◽  
Rajinder S. Dhindsa
Keyword(s):  
Protein Synthesis ◽  
Leaf Senescence ◽  
Altered Protein

INDIREKTE PAPIERCHROMATOGRAPHISCHE METHODE ZUR BESTIMMUNG DER HARNOESTROGENE

1961 ◽  
Vol 38 (4) ◽  
pp. 545-562 ◽  
Author(s):  
L. Kecskés ◽  
F. Mutschler ◽  
I. Glós ◽  
E. Thán ◽  
I. Farkas ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Granulosa Cell ◽  
Iron Content ◽  
List Type ◽  
Granulosa Cell Tumour ◽  
Hydrolysis Of ◽  
Phenol Fraction ◽  
Qualitative Determination

ABSTRACT 1. An indirect paperchromatographic method is described for separating urinary oestrogens; this consists of the following steps: acidic hydrolysis, extraction with ether, dissociation of phenol-fractions with partition between the solvents. Previous purification of phenol fraction with the aid of paperchromatography. The elution of oestrogen containing fractions is followed by acetylation. Oestrogen acetate is isolated by re-chromatography. The chromatogram was developed after hydrolysis of the oestrogens 'in situ' on the paper. The quantity of oestrogens was determined indirectly, by means of an iron-reaction, after the elution of the iron content of the oestrogen spot, which was developed by the Jellinek-reaction. 2. The method described above is satisfactory for determining urinary oestrogen, 17β-oestradiol and oestriol, but could include 16-epioestriol and other oestrogenic metabolites. 3. The sensitivity of the method is 1.3–1.6 μg/24 hours. 4. The quantitative and qualitative determination of urinary oestrogens with the above mentioned method was performed in 50 pregnant and 9 non pregnant women, and also in 2 patients with granulosa cell tumour.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

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