Influence of Cell Detachment on the Respiration Rate of Tumor and Endothelial Cells

Cell detachment is a procedure routinely performed in cell culture and a necessary step in many biochemical assays including the determination of oxygen consumption rates (OCR) in vitro. In vivo, cell detachment has been shown to exert profound metabolic influences notably in cancer but also in other pathologies, such as retinal detachment for example. In the present study, we developed and validated a new technique combining electron paramagnetic resonance (EPR) oximetry and the use of cytodex 1 and collagen-coated cytodex 3 dextran microbeads, which allowed the unprecedented comparison of the OCR of adherent and detached cells with high sensitivity. Hence, we demonstrated that both B16F10 melanoma cells and human umbilical vein endothelial cells (HUVEC) experience strong OCR decrease upon trypsin or collagenase treatments. The reduction of cell oxygen consumption was more pronounced with a trypsin compared to a collagenase treatment. Cells remaining in suspension also encounter a marked intracellular ATP depletion and an increase in the lactate production/glucose uptake ratio. These findings highlight the important influence exerted by cell adhesion/detachment on cell respiration, which can be probed with the unprecedented experimental assay that was developed and validated in this study.     

Assessing the Physiological State of the Fucoids from the Barents Sea Littoral by the End of the Polar Night

Methods of amperometry and potentiometric titration were used to follow dark respiration (DR) and apparent photosynthesis (AP) in the fucoids Ascophyllum nodosum (L.) Le Jol, Fucus vesiculosus L., and F. serratus L. from the Barents Sea littoral by the end of the 40-day-long polar night. The macroalgae were shown to manifest species-specific low rates of photosynthesis and respiration. However, in spite of their low photosynthetic status due to the effects of subzero temperature and prolonged low or zero illumination, the macroalgae have been able to restore DR and AP to the initial level already by the day 9; the ability to restore AP depended on the level of illumination. The study of the changes in the carbonate–bicarbonate system in the light and darkness demonstrated that the macroalgae grown in darkness, in contrast to those grown in twilight, could absorb bicarbonate in darkness; however, they lost this capacity after two-day-long illumination at an irradiance of 7 mol/(m² s). Bicarbonate uptake in darkness and the capacity to restore the systems of photosynthesis and respiration in fucoid cells are discussed in the context of algal energy metabolism under the polar night conditions.     

Effects of Selection for Dark Respiration Rate on Enzyme Genotypes in Lolium perenne

Two lines of perennial ryegrass (Lolium perenne) that had previouslybeen selected for ‘fast’ and ‘slow’rates of leaf dark respiration were examined to determine whetherselection had differentiated allelic or genotypic frequenciesof five polymorphic enzyme loci, and determine whether respirationrates differed among genotypes. The lines were differentiatedfor genes coding for phosphoglucose isomerase (PGI) and UDP-glucosepyrophosphorylase (UDP). Respiration rates were heterogeneousamong UDP and 6-phosphogluconate dehydrogenase (6PGD) genotypes.Founder effects may have produced the genetic differentiationof lines at the PGI locus as we detected no differences amonggenotypes for respiration rates. The genetic differentiationamong lines for UDP was consistent with differences in darkrespiration among genotypes. Although we detected large differences(75%) in dark respiration rate among 6PGD genotypes in the fastrespiring line, selection did not differentiate the lines atthis locus. Lolium perenne L., perennial ryegrass, enzyme polymorphisms, dark respiration rate     

Gamete Structure and Fertilization in the Barents Sea Sponge Leucosolenia complicata

The ultrastructure of male and female gametes of asconoid sponge Leucosolenia complicata(Calcispongiae, Calcaronea), a hermaphrodite species that reproduces in autumn, is described. The mature sponge's oocytes were up to 70 m in diameter, had no coatings, and contained a nucleus about 31 m in diameter with large nucleoli (up to 6.6 m). There were vacuoles with fibrillar contents typical of calcareous sponges in ooplasm. During vitellogenesis, a cluster of a great number of nurse cells developed above each oocyte from transformed choanocytes. Mature spermia of L. complicatalooked like orbicular cells about 2.5 m in diameter, with no acrosome or tail. The spermium nucleus (diameter about 2.2 m) was formed by incompletely condensed chromatin and was surrounded with a thin layer of cytoplasm of nonuniform thickness. In the thick layer of cytoplasm beyond the ribosomes, there were two or three mitochondria, dictyosomes, and electron-dense protein bodies lying freely under the nucleus. Fertilization occurred with the aid of a carrier cell. During spawning (mass release of spermia), any nurse cell complex can seize a spermium and transform into a carrier cell in situ. The transformation of a seized spermium into a spermiocyst was connected with the rapid isolation of the spermium nucleus from the protein body. Fertilization began with the penetration of the protein body into the oocyte cytoplasm. Only after this did the spermium's nucleus penetrate into the oocyte.     

Enzymatic Hydrolysis of Proteins from Crustaceans of the Barents Sea

Enzymatic preparations from king crab hepatopancreas were shown to be capable, in principle, of producing protein hydrolysates. Hydrolysis of protein-containing waste of deep-water prawn and king crab occurs most successfully at pH 8.0–8.5 and 50–55°C for 5–6 h in the presence of 6 g enzyme per kg substrate. The total chemical composition of the hydrolysates, the molecular weight distributions of proteins and polypeptides, and the contents of free amino acids were studied in dry hydrolysates.     

Enzymatic hydrolysis of proteins from crustaceans of the Barents Sea

Enzymatic preparations from king crab hepatopancreas were shown to be capable, in principle, of producing protein hydrolysates. Hydrolysis of protein-containing waste of deep-water prawn and king crab occurs most successfully at pH 8.0-8.5 and 50-55 degrees C for 5-6 h in the presence of 6 g enzyme per kg substrate. The total chemical composition of the hydrolysates, the molecular weight distributions of proteins and polypeptides, and the contents of free amino acids were studied in dry hydrolysates.     

Effects of Light and Dark on the Ultrastructure of Lichen Algae

Quantitative ultrastructural observations have been made onthe algal cells (Trebouxia) in two lichens, Parmelia sulcataand P. laevigata, stored for 48 h in the dark or under a light/darkregime. The response of the alga was found to differ in theselichens. In P. sulcata the dark treatment caused a decreasein starch grains, lipid-rich pyrenoglobuli and peripheral cytoplasmicstorage bodies and an increase in pyrenoid and chloroplast proteinbodies. The algae in P. laevigata contained little starch andno chloroplast protein bodies. However, after dark treatment,starch, cytoplasmic storage bodies and pyrenoid dimensions sometimesdeclined, while pyrenoglobuli numbers increased. Some of theseapparent changes depended upon the units used for calculatingthe cross-sectional areas of structures, e.g. absolute units,percentage of cell wall, protoplast or chloroplast cross-sectionalarea. Chloroplast area increased in the dark (as a % of cellwall area) in both species while mitochondria were larger inthe dark in P. sulcata but not in P. laevigata. Ultrastructuralchanges were not clearly correlated with changes in photosyntheticand respiratory rates. These results directly support the suggestionthat some intra-cellular structures are energy-generating reservesthe dimensions of which can rapidly change. Parmelia sulcata, Parmelia laevigata, lichen algae, light and dark storage, starvation, reserve substances, organdie dimensions     

Influence of Salinity Concentration on Aquatic Insect Community Structure: A Mesocosm Experiment in the Dead Sea Basin Region

Salinity varies considerably among temporary pools in the Dead Sea Basin, Israel. We experimentally assessed the effects of four salinity levels (0, 10, 20 and 30 g NaCl per liter) on the aquatic insect community in this basin in an artificial pool experiment. Each salinity level was randomly assigned to six pools (total=24 pools). Salinity did not affect total insect abundance but strongly affected abundance and distributions of different species, and consequently, community structure. Of 13 taxa colonizing the pools, 12 were Diptera including 10 mosquito species. Five taxa were sufficiently common to assess abundance in relation to salinity. Polypedilum nubiferum Skuse (Diptera: Chironomidae) was largely salinity intolerant being abundant only in the freshwater. Ephydra flavipes Macquart (Diptera: Ephydridae) was most abundant at the highest salinity level and was rare in freshwater. Ochlerotatus caspius Pallas (Diptera: Culicidae) abundance tended to be highest at 10 g/l and lowest at 30 g/l although the differences were not statistically significant. Anopheles multicolor Cambouliu (Diptera: Culicidae) was relatively euryhaline although numbers dropped significantly at the highest salinity. Cleon dipterum Linnaeus (Baetidae: Ephemeroptera) was also euryhaline and showed no significant differences in abundance across salinities. For the mosquito species, we also estimated survival to pupation. Survival to pupation was significantly lower for O. caspius in freshwater, but was not statistically significantly different across salinities for A.␣multicolor. Species diversity was highest at the two lowest salinities tested and then dropped with increasing salinity. Evenness was not significantly different across salinities. Community similarity generally decreased with increasing salinity differences though dissimilarity was greatest when comparing freshwater to other salinities. Thus, regional diversity is likely increased when there is a range of salinities among pools.     

褐藻裙带菜孢子叶粗提物体外抗单纯疱疹病毒Ⅱ型活性研究

从药物对细胞的保护、对HSV-2增殖的影响及对HSV-2感染细胞的综合作用三个方面研究不同稀释度的裙带菜孢子叶粗提物抑制单纯疱疹病毒Ⅱ型对Vero细胞的感染作用,细胞病变效应法(Cytopathogenic effect,CPE)观察和MTT法测定裙带菜多糖抗HSV-2活性,结果表明裙带菜多糖能明显抑制HSV-2对Vero细胞的致病变作用,使细胞存活率升高,其水提醇沉法所得裙带菜多糖的IC50为6.49μg/mL,并初步推测其抗HSV-2活性是作用在HSV-2和受体结合,侵入Vero细胞阶段,为筛选新型抗病毒药物、研究海藻多糖抗HSV-2活性机理及优化裙带菜孢子叶的提取工艺提供参考依据。     

The rotifer fauna of arctic sea ice from the Barents Sea,Laptev Sea [2pt] and Greenland Sea

Hydrobiologia - Samples from arctic sea ice were studied for their rotifer fauna. Ice core samples were collected in the northern Barents Sea and the Laptev Sea from August to October 1993 and in...     

Influence of Salinity on the Structure and the State of Bivalve Mytilus galloprovincialisPopulations

The influence of salinity on the structure and status of mussel Mytilus galloprovincialispopulations in the Black Sea was examined. Lowering salinity results in an increase in mortality rate and a decrease in numbers, biomass, juvenile recruitment, growth rates, and annual production. Low salinity produces changes in the size, age, sex, and phenotypic structure of mussel populations, namely, a decrease in the average size and age of mussels and an increase in the proportion of females and heterozygote deficiency.     

Microbiological analysis of cryopegs from the Varandei Peninsula, Barents Sea

The paper deals with the microbiological characterization of water-saturated horizons in permafrost soils (cryopegs) found on the Varandei Peninsula (Barents Sea coast), 4-20 m deep. The total quantity of bacteria in the water of cryopegs was 3.5 x 10(8) cells/ml. The population of cultivated aerobic heterotrophic bacteria was 3-4 x 10(7) cells/ml and the number of anaerobic heterotrophic bacteria varied from 10(2) to 10(5) cells/ml depending on cultivation temperature and salinity. Sulfate-reducing bacteria and methanogenic archaea were found as hundreds and tens of cells per ml of water, respectively. A pure culture of a sulfate-reducing strain B15 was isolated from borehole 21 and characterized. Phylogenetic analysis has shown that the new bacterium is a member of the genus Desulfovibrio with Desulfovibrio mexicanus as its closest relative (96.5% similarity). However, the significant phenotypic differences suggest that strain B15 is a new species of sulfate-reducing bacteria.     

Microbiological analysis of cryopegs from the Varandei Peninsula,Barents Sea

The paper deals with the microbiological characterization of water-saturated horizons in permafrost soils (cryopegs) found on the Varandei Peninsula (Barents Sea coast), 4–20 m deep. The total quantity of bacteria in the water of cryopegs was 3.5 × 10⁸ cells/ml. The population of cultivated aerobic heterotrophic bacteria was 3–4 × 10⁷ cells/ml and the number of anaerobic heterotrophic bacteria varied from 10² to 10⁵ cells/ml depending on cultivation temperature and salinity. Sulfate-reducing bacteria and methanogenic archaea were found as hundreds and tens of cells per ml of water, respectively. A pure culture of a sulfate-reducing strain B15 was isolated from borehole 21 and characterized. Phylogenetic analysis has shown that the new bacterium is a member of the genus Desulfovibrio with Desulfovibrio mexicanus as its closest relative (96.5% similarity). However, the significant phenotypic differences suggest that strain B15 is a new species of sulfate-reducing bacteria.     

Checklist of fauna found in zooplankton samples from the Barents Sea

We present a list of zooplankton taxa occurring in the Barents Sea based on our analysis of 360 samples from the upper 100 m of the water column as well as on reports from published sources. Moreover, we provide information on adult size, ecological and geographical distribution, habitat preference and frequency of occurrence of each taxon. The list encompasses a total of 374 species and higher taxa. Most are mesozooplankton, with Copepoda prevailing (153 species), and belong to the holoplankton. However, pseudoplankton, organisms only circumstantially occurring in the water column, also comprise a significant part of the fauna (86 taxa). The coastal zooplankton (264 neritic species) was richer than the fauna of the open sea. In our samples, the majority of the zooplankton taxa were rarely found (94 of 157 taxa, equivalent of 60%), 46 taxa (29%) were moderate and only 17 taxa (11%) were common (found in >80% of the samples). Among these, the copepods Calanus finmarchicus, C. glacialis, Oithona similis and Pseudocalanus minutus were most frequent.