Synthèse et dégradation des composés glucidiques au sein de la communauté planctonique en zone marine eutrophe

A general study on the relations between “phytoplanktonic excretion” and “heterotrophic assimilation” has been carried out in eutrophic systems, natural or artificial. In the complex systems of these relations, two types of heterotrophic responses were obtained according to prevailing algal species. High heterotrophic potentials in NW African upwelling show the role of microorganisms in the disappearance of freshly excreted organic substances and in the composition of the remaining organic matter.     

Etude de la fertilité des eaux marines au moyen de tests biologiques effectués avec des cultures d'algues I. Comparaison des méthodes d'estimation

Several methods of growth potential estimation of marine productivity are discussed: (1) simultaneous measurements of nutrient content and organic production, (2) chemical composition of algal cells, (3) bioassay with algal cultures. This last method appears to be the most convenient; it allows to study the role of a nutrient component both when utilized alone and when combined in a pool of nutrients. Several aspects of bioassay technology are discussed: test species, chemical enrichments and growth estimation of test cultures.     

Typologie de bactéries prélevées devant le delta du Rhöne. Classification hiérarchique par une méthode d'agrégation suivant la variance. Clustering of Bacteria Isolated Seaward from the Rhǒne Outlet. Hierarchical Classification Using the Method of Aggregation According to Variance

Bacteria isolated from surface sea waters, brackish waters and from algal cultures were studied to attempt a nutritional clustering. A hierarchical method, using aggregation according to variance, was used to compute the data. Six nutritional groups had been separated by differences in genus composition and nutritional characteristics. Groups range from one with bacteria which are poorly versatile, i.e. attach few different substances, and which grow on sugars, amino-acids and organic acids without any selectivity, to one with bacteria which are versatile, and which attack numerous organic acids and amino-acids, but only a few sugars. Bacteria from different origins are not spread randomly in the different clusters. Strains isolated from algal cultures are mainly associated with the lowest versatility; those isolated from the undiluted sea water are associated with the highest versatility. Bacteria from diluted sea waters appear to be intermediate in regard to their capability of using organic substances as their sole source of carbon. It also appears that organic acids provide individually the most discriminating substrates, i.e. the most useful for separating individual groups, but amino-acids and organic acids, as a whole, are not easy to use in classification, because they are too heterogeneous. Sugar contribution to classification is almost nil.     

Typologie de bactéries prélevées devant le delta du Rhǒne. Utilisation d'une méthode objective: L'analyse des correspondances

Bacteria isolated from surface sea waters, brackish waters and from algal cultures were classified in nutritional clusters. Results obtained with an hierarchical method were improved by using the correspondence analysis. The former main statements appear confirmed and new informations are pointed out, mainly concerning the organic compounds which are the best indexes of the nutritional characteristics; e. g. a few organic acids and amino-acids can be used to estimate the versatility of bacteria; it also appears that strains which preferentially assimilate substrates of one chemical group, do not easily attack substances of other groups.     

Some aspects on the role of bacteria in deep water ecosystems

Summary Some remarks on the role of bacteria in deep lakes will be presented with an emphasis on their functioning in the carbon cycle in such ecosystems.The metabolic intensity of most lakes is regulated to a large extent at the primary producer level. Aerobic and anaerobic decomposition by heterotrophic bacteria of the unstable ultimate products of photosynthesis results in the production of carbon dioxide and methane. Bacterial growth occurs at the expense of energy released by the flow of electrons from donors to acceptors. Typical electron acceptors for bacterially mediated reactions are oxygen, nitrate, sulphate and carbon dioxide. When oxygen is used as electron acceptor, the highest amount of energy is released, while the lowest is released when carbon dioxide is used. These reactions are mediated biologically, and the chemical reaction sequence is paralleled by an ecological succession of microorganisms: aerobic heterotrophs, denitrifiers, fermenting bacteria, sulphate reducers, and methane producers. The presence of oxygen is inhibitory to the organisms mediating the last reactions (STUMM, 1966; McCARTY, 1972), and this explains the succession of micro-organisms concomittant with the decrease in redox potential.Both labile and refractory fractions of the pelagial dissolved organic matter can directly be utilized largely by heterotrophic bacteria. At the onset of the summer stratification of Lake Vechten a high concentration (numbers 10⁹ bact/L) of heterotrophic bacteria has been detected in the lower water layers (CAPPENBERG, 1972). The reason for this increase may be a release of nutrients from the mud. During stratification the water layers above the mud become anaerobic owing to the metabolic activity of the bacterial flora and the chemical oxygen demand of the mud. In summer time the highest numbers of heterotrophic bacteria are found in the metalimnion, where organic matter accumulates due to a lower relative rate of sedimentation caused by an increase in viscosity and density.Furthermore it was found that sulphate-reducing bacteria which are capable of reducing sulphates to sulphides using sulphate as terminal electron acceptor, were observed in the hypolimnion only at the time of maximal stratification. During stagnation, gradually decreasing sulphate concentrations are found in the hypolimnion, correlated with increaseing cell numbers of sulphate reducers. As no sulphate could be detected in the mud of Lake Vechten as well, we may conclude that the sulphate concentration limits the number of these bacteria, as can be predicted for similar aquatic environments.Usually the sulphate reducers are found in bottom deposits and are an important group of bacteria of the non-methanogenic populations in mud. Summarizing the biological methane production and its subsequent oxidation by methane-oxidizing bacteria, we may conclude that these processes can be important factors functioning in the carbon cycle in deep fresh-water ecosystems.     

赤泥自然成土过程及其微生物驱动机制

氧化铝废渣(赤泥)堆场生态修复的关键是赤泥土壤化。运用空间代替时间的方法,在未采取人工修复措施的赤泥堆场采集具有时间序列特征的赤泥样品,通过测定其理化生化指标及微生物群落结构变化,研究赤泥的自然成土过程及其微生物驱动机制。结果表明: 随赤泥泥龄的增加,其物理指标孔隙度、水稳性团聚体含量、团聚体平均重量直径提升,容重降低;化学指标pH值、电导率、酸中和能力和交换性钠饱和度降低;生化指标有机碳、总氮、有效态磷、微生物生物量碳、土壤基础呼吸提升,代谢熵降低。微生物Shannon多样性指数增加,群落结构由产氧光合细菌蓝细菌门、不产氧光合细菌绿菌门和绿弯菌门占据绝对优势转变为变形菌门、放线菌门和厚壁菌门占据优势地位,富营养细菌与贫营养细菌丰度比值明显增加。微观形态分析表明,微生物及其代谢产物通过对赤泥颗粒的吸附、链接、缠绕及包裹形成微生物-赤泥聚合体。在自然堆置过程中赤泥自发地由贫营养的极端生境向土壤生境转变,微生物通过提升营养水平、降低盐碱度、改善质地结构等途径参与赤泥的自然成土过程。     

Caractérisation de la membrane liée au chromosome replié isolé de Escherichia coli

Phospholipid analysis of the membranes associated with fast sedimenting folded chromosomes prepared by lysis of E. coli CR 34 shows that both inner and outer membranes are parts of the complex, in proportions not very different from that found in the whole bacteria.During the preparation of the folded chromosomes, the most recently synthesized molecules of phosphatidylglycerol and phosphatidylethanoamine are more sensitive to solubilisation, particularly those from the cytoplasmic membrane. Identification of a dominant fraction, the outer membrane, in some complexes, results from a preferential solubilization of the inner membrane.These results do not favor any specific association between the folded chromosome and the membranes.     

Seasonal Incidence of Bacterial Temperature Types in Louisiana Soil and Water

Psychrophilic bacteria were not detected in soil, mud, and water in the summer. In winter, they were present in water and mud and constituted a significant portion of the bacterial flora in lake water.     

含酚废水处理高效菌株的筛选

酚类化合物属于持久性有机污染物,含酚废水在我国水污染控制中被列为需要重点解决的有害废水之一。本文通过对本钢焦化厂含酚分废水处理工艺中曝气池内活性污泥所含未知菌株进行分离纯化,并经过对酚的耐受性实验和降解率实验,得到处理酚的高效菌株。通过对筛选出的菌株进行细胞个体形态和菌群形态特征观察及一系列生理生化实验,确定筛选出来的7株能高效降解盼的菌株为假单胞菌。本文的实验结果将有利于今后对含酚废水的处理。     

Degradation of Macromolecular Organic Compounds in a Tropical Lagoon (Ciénaga Grande,Colombia) and its Ecological Significance

Primary production and decomposition of organic substances were investigated in a tropical lagoon during the rainy season. Production and mineralization were measured using the oxygen method. Total bacteria numbers and biomasses were estimated with epifluorescence microscopy, and the enzymatic degradation capacity of model substrates was determined photometrically. These parameters were measured in the water and sediment of the lagoon itself and also in its effluents and incoming waters. The aim of the study was to determine the sites of highest microbial activity in the lagoon and to compare its activity with other coastal water bodies. Since the shallow water lagoon contains a large amount of particulate matter, it was of special interest to study the degradation of this material and its influence on the microbial population. It was found that up to 14 % of the bacteria colonized the particles and that 62 % of the respiration originated in the particle fraction >8 μm. Highest exoenzymatic activities were measured in the sediment and water of the mangrove belt. It is concluded that decomposition and conditioning of particulate organic matter play dominant roles in the recycling of organic carbon in the lagoon.     

Approche discriminante de contributions de différents échelons microplanctoniques aux mesures globales d'ETS dans des échantillons de mer. b. Bacteria

Discriminating approach of various microplanktonic-stage contributions to whole electron transport system (ETS) measurements in sea-water sampless. b. Bacateria Data obtained from cultures of natural bacterial populations were applied to various water samples in order to determine both the phytoplanktonic and bacterial contributions to whole ETS water-sample measurements. The bacterial part was estimated both by cell enumerations and HPLC muramic-acid measurements and the phytoplankton contribution by enumeration and chlorophyll levels. An appropriate first-order equation is adequate to low carbon content samples but must be corrested for highly organic loaded samples in order to obtain a better adjustment between the sum of the “estimated” phytoplanktonic and bacterial ETS and the really-measured ETS concentrations in the water samples.     

洋河酒窖泥细菌群落结构与菌株产酸能力分析

【背景】窖泥微生物的种类及其代谢产物类型是影响浓香型白酒发酵过程中丁酸和己酸等白酒中主要有机酸合成的影响因素之一。【目的】揭示浓香型白酒不同窖龄窖泥细菌群落结构,研究厌氧细菌产酸性能,阐明窖泥细菌与白酒中有机酸合成的相关性。【方法】通过Illumina HiSeq高通量测序,基于16S rRNA基因序列分析不同窖龄窖泥细菌的组成。分离获得厌氧细菌,通过比较菌株产丁酸和己酸能力来分析窖泥的微生物代谢特性。【结果】洋河酒窖泥细菌主要分布于梭菌纲(Clostridia)、拟杆菌纲(Bacteroidia)、互营养菌纲(Synergistia)和芽孢杆菌纲(Bacilli)。20年窖龄的窖泥中氢孢菌属(Hydrogenispora)和瘤胃梭菌属(Ruminiclostridium)丰度显著增加。窖泥细菌间相关性分析表明,瘤胃梭菌属(Ruminiclostridium)为窖泥中影响最大的核心微生物,很多微生物与梭菌属(Clostridium)菌株之间多为相互促进关系。通过传统可培养方法共分离得到梭菌目(Clostridiales)的20株厌氧菌。其中梭菌属(Clostridium)菌株产酸能力高...     

Etude de la fertilité des eaux marines au moyen de tests biologiques effectués avec des cultures d'algues. II. Limitation nutritionnelle et viabilité de l'inoculum

Ten cultures of phytoplankters, including four strains of Skeletonema costatum from different origins, were used to improve some aspects of the bioassay technology. Special attention was paid to the preliminary nutrient limitation of the inocula. When the cells are maintained in nutrient starvation, their carbon, nitrogen, carbohydrates, proteins and above all chlorophyll a contents decrease. The minimum appears after a range of 2–7 days, according to species. The survival of these limited cells and their capacity to give rise to active growing cultures when sub-cultured are different with species, but efficiency in the inocula they provide usually can occur only until the minimum content in cellular components appears. Starved cells and enriched cultures of Chaetoceros lauderi and Skeletonema costatum were used to inoculate several samples of sea water, in order to test the effect of the starvation on the experimental results. It appears that the starved cells increase the sensitivity of the method, but they are more susceptible to substances limiting their growth. In the opinion of the authors the best way would be to use both starved and enriched cells as inocula, but, when this is impossible, cautiously starved cells should be used with unpolluted sea waters.     

Synthèse des RNA au cours de la germination du radis

RNA synthesis in radish is studied during the first stages of germination. The radish seeds allowed to germinate in the dark, on distilled water, synthesize ribosomal RNA and accumulate a particular RNA, not incorporated in ribosomes. The results of ³²P incorporation in RNA of radish seedlings indicate a progressive formation of ribosomal RNA. Two species of rapidly labelled RNA are synthesized. With labelling time, their chromatographic behaviour on MAK columus evolves, while their electrophoretic characteristics remain stable. It is assumed that these two species are involved in ribosome formation. In vivo experiments with chloramphenicol support this conclusion. RNA which accumulates during germination, could be a particular type of ribosomal RNA which could be enable, under the definite culture conditions, to enter into ribosomal structures.     

Modifications des propriétés cytophotométriques des ADN et des histones nucléaires au cours de la sénescence des tritons (Triturus vulgaris et Triturus cristatus)

DNA and histones were studied by cytophotometry, in cartilaginous cells from urodele amphibians (Triturus vulgaris and Triturus cristatus) during ageing. With the Feulgen reaction, the DNA colorability decreased and their acid hydrolysis was more difficult. The coloration of the histones linked to DNA in chromatin was also changed. The results are discussed in relation to numerous works on deoxyribonucleoprotein modifications during cell ageing.ADN et histones ont été étudiés par cytophotométrie dans les cellules cartilagineuses d'Amphibiens Urodèles (Triturus vulgaris et Triturus cristatus) au cours du viellissement. Nous avons observé une baisse des affinités tinctoriales des ADN et une augmentation de leur résistance á l'hydrolyse acide pratiquée dans le cadre de la réaction de Feulgen. La colorabilité des histones associées aux ADN dans la chromatine est aussi modifiée. Tous ces résultats sont discutés en liaison avec les nombreux travaux effectués sur les modifications des désoxyribonucléoprotéines au cours du viellissement cellulaire.     

Repartition des Appendiculaires au large des cotes de Californie

Twenty-seven taxa of appendicularians have been identified fromthe cruise CALCOFI n° 7202 and their distribution has beenstudied by various numerical methods, with the purpose of definingsimultaneously the groups of associated species and the groupsof stations possessing similar characteristics. Two large recurrentgroups have been defined by the method of Fager and McGowan,corresponding approximatively to the major water masses present:central Pacific waters and equatorial Pacific waters. The methodof Williams and Lambert permits the separation of 11 southernstations and a northern group divided into 2 subgroups dependingon the presence or absence of O. dioica. The rank correlationsgive results very similar to those obtained with point correlations.Finally, principal component analysis allow good separationof the northern and southern zones by the factorial plan 1–3,while representation of the stations by the factorial plan 2–3separates the two northern subgroups depending on the presenceor absence of O. dioica. The results obtained by the differentmethods are therefore very much alike, but it is difficult toconclude they are a result of the specific cruise, or whetherthey represent a general phenomenon.     

Productivité comparée des deux étangs situés à proximité du lac Saint-Jean,au Québec

The Comparative Productivity of Two Ponds in the Vicinity of Lake St-John, Québec In 1980 and 1981, the productivity of two ponds near Lake St. John were evaluated. One, the pond of Desbiens, did not communicate with Lake St. John and the other, the pond of St-Gédéon, was connected to the lake. The aim of this study was to evaluate the contribution that a pond could make to the increase in productivity of Lake St. John which is a reservoir. The pond of Desbiens is more productive than Lake St. John but two to three times less than the pond of St-Gédéon. The pond of Desbiens shows an advanced degree of eutrophication whereas the pond of St-Gédéon is similar to the northern lakes by its physico-chemistry, zooplankton, sediments and benthic fauna. If we want to create artificial ponds, for a better productivity of reservoirs, it is important that they be connected to each other.