STUDIES OF THE DETERMINATION OF THE BACTERIUM COLI TYPE I CONTENT OF FARM WATER SUPPLIES

SUMMARY: A – comparison of the suitability of brilliant green bile broth and MacConkey's broth at 44° for the detection of Bacterium coli type I in farm water supplies, showed that 83.1% of the samples had no difference in the number of positive tubes at 44°, and only 5 samples (1.7%) had a significantly higher number of positive tubes in MacConkey's broth.
Of 707 strains of coli-aerogenes bacteria isolated from 44° positive tubes of both media, 94.5% were Bact. coli type I. Strains of Bact. coli type II and Bact. aerogenes type I which were 44° positive constituted 3.7% and 0.4% respectively, all of which were indole negative at 44°. In addition there were 10 strains (1.4%) of 44° positive Intermediate type II, 9 of which were indole positive at 44°.
An appreciable number (6.6%) of Bact. coli type I strains failed to give a positive indole reaction in 24 hr at 44°.     

COLI-AEROGENES BACTERIA IN FARM WATER SUPPLIES

SUMMARY: A series of 825 cultures of coli-aerogenes bacteria isolated at 30° and a series of 735 cultures isolated at 37° from 645 samples of farm water supplies were classified according to the recommendations of the Coliform Sub-Committee of the Society for Applied Bacteriology (Report, 1949). Klebsiella constituted 50% of the cultures isolated at 30°, whereas Escherichia coli I was the dominant type, forming 57%, among the cultures isolated at 37°. It would thus appear that isolation at 30° is as selective for Klebsiella as isolation at 37° is for Escherichia . Coli-aerogenes organisms, mainly 37° negative strains of Citrobacter freundii I and K. cloacae , were found in waters of high sanitary quality derived from protected springs and wells; but the coli-aerogenes microflora of polluted water was dominated by E. coli I, which formed 43% of the isolates at 30° and 76% of those at 37°. The results for a series of fortnightly samples from 11 farm water supplies showed a marked seasonal variation in the incidence of different types isolated at 30°; E. coli I formed a higher proportion in summer than in winter, while 37° negative strains of Klebsiella and Citrobacter formed a higher proportion in winter than in summer.     

FURTHER OBSERVATIONS ON THE BACTERIAL CONTENT OF WATER IN WATERCRESS BEDS

SUMMARY: Observations on two watercress beds in Kent have confirmed previous findings (Jones & Baker, 1955) that even in comparatively well-protected beds the coli-aerogenes content of the water may be high in summer. They have also shown that in spite of circumstances which would lead one to expect pollution, as in the case of one bed, the coli-aerogenes content can be low in winter. The season appears to influence the content in the water of coli-aerogenes bacteria, pectate liquefying bacteria and those capable of growing at 37°, but in the case of those growing at 22° other factors can play a more important part, as higher counts were not uncommon in winter. Seasonal effects were less marked with inlet samples; they were less influenced by atmospheric temperature, and little extraneous contamination occurred. Numbers increased as the sampling point moved from inlet to outlet.     

MARINE BACTERIA OF CARDIGAN BAY. I. BACTERIA OF AN OFF-SHORE AREA

SUMMARY: A study of marine bacteria from a fixed off-shore area in Cardigan Bay showed there was little significance in the variation between numbers from different levels within 8 fathoms deep. There was a suggestion of seasonal variation in surface water in colony counts at 15–18°. In general, the bacterial content was highest over the summer months, but showed little direct correlation with temperature, pH or light.
Strains were mainly obligate halophytes and small Gram-negative rods predominated (96%). Nearly 50% of strains isolated liquefied gelatin; otherwise, biochemical reactions were weak. The proportion of pigmented strains was low.
Alien bacteria were present in irregularly varying numbers in all samples and showed no seasonal variation. Coli-aerogenes strains were recorded in small numbers, at all depths and in all seasons, but Bact. coli type I only rarely occurred.     

THE INCIDENCE OF BACTERIUM COLI IN FARM WATER SUPPLIES

SUMMARY: Farm water supplies giving 37° positives in MacConkey's broth within 24 hr. had a much higher incidence of presumptive Bact. coli type I than those which gave 37° positives during the second day of incubation only; presumptive Bact. coli reactions were obtained with 85% of the 7,522 tubes positive in 24 hr. compared with 23% for the 7,593 tubes showing positive reactions during the second day at 37°.     

SURVIVAL OF BACTERIUM COLI TYPE I AND STREPTOCOCCUS FAECALIS IN SOIL

SUMMARY: Differences have been noted in the numbers of excretal organisms isolated from water supplies coming from gathering grounds with soils of different types. Those from acid moorlands normally contained smaller numbers of Bact. coli type I than those from limestone areas, although the numbers of animals present in the areas were approximately the same.
The technique is described for a study of the effect of soils from these areas on the survival of excretal organisms. Incubation of samples of the soils after inoculation with Bact. coli type I and with Strep. faecalis has shown that both organisms will persist in the limestone soils for several weeks but die out in a few days in acid peat soils. When chalk is added to the acid soils both organisms were able to persist for several months. It is suggested that survival is largely governed by pH.     

THE BACTERIOLOGY OF FARM WATER SUPPLIES: A STUDY OF THE COLONY COUNT IN 72 HOURS AT 22°

SUMMARY: The colony count at 22° of farm water supplies from springs and wells was mainly composed of biochemically inactive, non-pigmented, Gram-negative rods. Water from a stream polluted with farmyard sewage showed a similar dominance of Gram-negative rods, but orange or yellow pigmented colonies were more abundant. There were few 37° positive coli-aerogenes bacteria in either the farm water supplies or the sewage polluted stream, and Bact. coli type I was rare.
A high proportion of the bacteria from farm water supplies fermented milk in 3 days at 22°; a third developed acid, 15% proteolysis and 6.4% ropiness.
Contamination of pure spring water with surface soil from a heavily grazed pasture resulted in a hundredfold increase in colony count with aerobic sporing rods replacing Gram-negative rods as the dominant organisms, but coli-aerogenes bacteria were absent.     

COLI-AEROGENES BACTERIA FROM FARM DAIRY EQUIPMENT AND RAW MILK

SUMMARY: A series of 1,040 cultures of coli-aerogenes bacteria isolated at 30° from farm dairy equipment and raw milk was classified according to the recommendations of the Coliform Sub-Committee of the Society for Applied Bacteriology (Report, 1949). The distribution of species and types isolated from milk did not differ materially from that for dairy equipment, Klebsiella cloacae, K. aerogenes and Citrobacter freundii being the dominant species, while the incidence of Escherichia coli was relatively low. There was no marked seasonal incidence of any type, though E. coli I formed a slightly higher proportion of the coli-aerogenes microflora in winter, whereas K. aerogenes I was slightly higher in summer. Many of the cultures of the dominant types, K. cloacae, K. aerogenes I and Cit. freundii I, did not form acid and gas from lactose in two days at 37°. Consequently 37° negative, anaerogenic and paracolon strains constituted a relatively high proporton (49%) of the coli-aerogenes microflora.     

Bacterial Flora of the Hemolymph of the Blue Crab, Callinectes sapidus: Most Probable Numbers

The hemolymph of 290 freshly collected blue crabs from Chincoteague Bay, Va., was sampled over a 15-month period from August 1968 through November 1969 and most probable numbers of bacteria were determined by tube dilution. The hemolymph of 18% of all crabs sampled was found to be sterile, with 16% sterility in summer and 23% in winter samples. Despite individual variations, male crabs as a group had a higher bacterial hemolymph burden than females, and among both sexes summer counts were higher than winter. The hemolymph of crabs with missing appendages had significantly higher counts than uninjured crabs. The annual mean hemolymph most probable numbers per ml was 2,756 for males, 1,300 for females, and 1,876 for both sexes. The higher bacterial levels found in the hemolymph of male crabs may, in part, be explained by the fact that males, which predominated in the summer samples, had a higher incidence of injury and missing appendages than did females.     

Phototrophic sulfur bacteria and sulfate-reducing bacteria causing red waters in a shallow brackish coastal lagoon (Prévost Lagoon, France)

Abstract In the shallow lagoon of Prévost (43°30'N, 3°54'E; French Mediterranean coast), red waters occurring periodically during warm summers are a consequence of a succession of ecological events beginning in the early spring with a bloom of algae ( Ulva lactuca ). In summer 1977, a red water was analyzed; in the early summer, the water turned anoxic and became rich in sulfide which originated from sulfate reduction in the first 10 cm of the sediment. Numbers of both phototrophic and sulfate-reducing bacteria (SRB) increased during spring and summer, and the genera in the prevailing populations did not change: Thiocapsa (80%) among the phototrophic bacteria and Desulfovibrio and Desulfobacter among the SRB. They were also dominant during the period of red waters. A few Chromatium and Thiocystis species were also identified. During red water periods, these bacteria grew very actively, removing all the sulfide produced by SRB, and accumulated in the whole water column. Consequently, the sulfate level increased to 5 mmol·1⁻¹ higher than the theoretical sulfate level calculated from salinity, showing the active oxidation of sulfide by phototrophic bacteria. After the dystrophic crisis, oxic conditions were reestablished and the phototrophic bacterial biomass was partly grazed by zoobenthos organisms which densely populated the sediment surface.     

北京四海浮游藻类叶绿素含量与水体营养水平的研究

1987年1-12月对北京四海叶绿素含量进行了逐月测定,结果表明,各海叶绿素含量明显不同。四海叶绿素含量年均变化在0.0075-0.0259mg/L之间,其中以前海为最低,北海为最高。叶绿素含量有明显的季节变化,冬季最低,夏、秋季最高。四海叶绿素a的含量随水温、色度、悬浮物、BOD5、COD、总磷、总氮、藻类数量的增加而增加,随水体透明度的上升而下降。用叶绿素含量作为指标对四海富营养程度评价结果为:西海、后海、前海为中略偏富营养,北海为富营养水体。       

Removal and inactivation of indicator bacteriophages in fresh waters

AIMS: The removal and inactivation of faecal coliform (FC) bacteria, enterococci (ENT), sulphite-reducing clostridia (SRC), somatic coliphages, F-specific RNA bacteriophages and bacteriophages infecting Bacteroides fragilis in fresh waters. METHODS AND RESULTS: Removal was studied in two areas of a river. The results showed different removal of each group of microbes. Faecal coliform bacteria were removed faster than any other, whereas SRC and bacteriophages infecting Bact. fragilis were the most persistent. Inactivation was measured by 'in situ' experiments, which showed significant differences in survival of the different groups of bacterial and bacteriophage indicators. The SRC and bacteriophages were more resistant than faecal coliforms and enterococci, with the exception of F-specific RNA bacteriophages in the summer. Inactivation experiments with pure cultures of bacteriophages confirmed that phage B40-8 of Bact. fragilis was the most resistant. CONCLUSIONS: Bacteria and bacteriophages show different resistance to natural inactivation. The use of phages allows information to be obtained in addition to that provided by bacterial indicators. Somatic coliphages and phages infecting Bact. fragilis might supply that indicator function. SIGNIFICANCE AND IMPACT OF THE STUDY: Confirmation was obtained that bacteriophages provided additional information to that provided by bacterial indicators to monitor the natural inactivation of viruses and/or pathogens.     

WIREWORM POPULATIONS IN RELATION TO CROP PRODUCTION: III. POPULATION CHANGES AFTER SUMMER PLOUGHING

Six permanent pastures broken up in the summer of 1943 were sampled once a fortnight after ploughing in order to study changes in the wireworm populations.
The graphs of the running means of four consecutive counts showed the chief trends in population. On four of the fields, a slight increase in population was apparent up to December. Only in February and March was a definite decline apparent. On the other two fields, the counts declined by about 30 % during the autumn and winter.
A marked fall in population (from 30 to 70%) was evident on all the fields only after the first crop had been harvested. The new population at this time was characterized by an absence of larvae less than 4 mm. in length.
The results considered alone indicate that after summer ploughing the wireworm population remains unaffected until the following spring and summer during the cropping period. When the results are considered in relation to the grass 'controls', it appears that a net decline in population occurs during the autumn and winter and that the decline in spring and summer is not more marked than that which normally occurs at this time in grass fields. Unlike the grass fields, however, the reduction is permanent.     

Thymidine Incorporation by Free-Living and Particle-Bound Bacteria in a Eutrophic Dimictic Lake

The percentage of [methyl-³H]thymidine incorporated into samples from a dimictic eutrophic lake and retained on polycarbonate membranes of 3.0-, 1.0-, and 0.2-μm pore size was studied in a lake with filamentous cyanobacteria as the dominant phytoplankton type throughout the period of thermal stratification. Water samples were also examined by epifluorescence microscopy for evidence of algal senescence and bacterial colonization of intact and damaged cyanobacterial filaments. A small percentage (2 to 20%) of bacterial activity was retained by filters with pore sizes ≥ 1 μm in epilimnetic samples. Epilimnetic samples also had a small percentage of cyanobacterial filaments, either intact or damaged, which were visibly colonized by bacteria in summer and fall samples. A significant proportion (20 to 35%) of bacterial activity was retained by filters with pore sizes ≥ 1 μm in samples collected from the metalimnion and hypolimnion during late summer and fall. The proportion of damaged cyanobacterial filaments was higher in these samples than in those from the epilimnion or from those obtained early in the summer. Furthermore, the filaments in these samples were more heavily colonized by bacteria. Overall, particle-bound production accounted for only 2 to 19% of total bacterial production from April to August in all water layers. It appears that the supply of colonizable particles (damaged cyanobacterial filaments) is an important factor affecting the level of particle-bound bacterial activity in this lake.     

保安湖水体细菌群落结构时空变化特征及驱动因子

为了探究保安湖水体细菌群落结构时空变化特征及驱动因子,研究于2019年春、夏、秋、冬四季采集保安湖水样,使用宏基因组测序技术对保安湖水体细菌群落的组成及多样性变化进行了研究。结果表明:(1)保安湖不同湖区细菌群落组成无显著差异(P>0.05);夏、秋季细菌丰富度、均匀度、香农及辛普森多样性指数均显著高于春、冬季(P<0.05),夏、秋季优势类群为变形菌门(Proteobacteria)、放线菌门(Actinobactetiota)、蓝藻门(Cyanobacteria),而春、冬季变形菌门(Proteobacteria)和放线菌门(Actinobactetiota)占主导地位;(2)温度、透明度、pH、溶解氧、高锰酸盐指数、叶绿素a及总磷等因素是保安湖水体细菌群落结构变化的重要驱动因子;(3)保安湖细菌群落构建过程在春、夏、秋季由随机性过程主导,在冬季由确定性过程主导;(4)保安湖细菌网络互作具有明显的季节特征,从春季到冬季,保安湖细菌种间相互作用逐渐紧密复杂。综上所述,保安湖水体细菌群落结构具有明显的季节变化特征,温度、透明度、pH、溶解氧、高锰酸盐指数等因素具有驱动水体细...     

Growth rate and physiology of Yersinia enterocolitica; influence of temperature and presence of the virulence plasmid

The effect of temperature on the growth rate, protein pattern and fatty acid composition of Yersinia enterocolitica strain W22703 pYV⁺, its plasmidless isogenic derivative W22703 pYV^- and four recent field isolates was examined.
The growth rate was clearly influenced by presence or absence of the virulence plasmid: pYV^- strains grew consistently faster than pYV⁺ strains. This difference in growth rate was high at 30–35°C, moderate at 1–10°C and 25°C, but hardly significant at 15–20°C.
Increasing the growth temperature above 25°C resulted in the induction of the 220 kDa virulence plasmid-encoded Yop1 protein. In the 1–20°C range no obvious temperature- or plasmid-related differences in protein patterns could be detected.
The fatty acid composition showed a clear temperature-dependent change: with all strains the degree of saturation was low at 1°C and gradually increased with raising temperatures. All strains had similar fatty acid patterns, except one of the field isolates which showed aberrant C16 : 1 and cyclic fatty acid contents in the 5–25°C and 15°C ranges respectively. With strain W22703, the presence or absence of the virulence plasmid did not significantly alter the fatty acid pattern.     

Production of cell wall dissolving enzymes by Erwinia carotovora subsp. atroseptica in vitro at 27°C and 30°5C

Cultures of Erwinia carotovora subsp. atroseptica , grown at 27°C and 30·°C in different liquid media were assayed for activities of pectate lyase, polygalacturonase and cellulase. Total production of both pectate lyase and of polygalacturonase was 3–6 times less at 30·5°C than at 27°C; secretion of pectate lyase was similarly affected. Cellulase was cell bound and its production was not affected by the temperatures investigated. Growth, protein synthesis and protease activity were similar at the two temperatures and production of enzyme activity at 27°C and 30·5°C was independent of the growth medium.     

环境因素对东平湖沉积物细菌群落结构的影响

【目的】探讨环境因素对东平湖沉积物细菌群落结构的影响。【方法】应用T-RFLP(Terminal RestrictionFragment Length Polymorphism)技术分析和比较了6个不同位置的东平湖沉积物在丰水期和枯水期的细菌多样性,并结合不同样品环境因子的差异,采用主成分分析(PCA)和典型对应分析(CCA),探讨了环境因子对细菌多样性的影响。【结果】不同沉积物样品的T-RFLP图谱具有较高的相似性。除2号样品外,所有枯水期样品的细菌群落具有较高的丰富度、多样性、均匀度和较低的优势度。CCA结果表明,558bp T-RF的丰度与总磷、总氮、总有机碳、铵态氮和硝态氮含量呈负相关而与碳氮比和水深呈正相关;64.5、164、509和543bp T-RFs的丰度与总氮、总有机碳、铵态氮、硝态氮、碳氮比和水深呈正相关;而其它14种主要的T-RFs在不同样品间分布较为稳定受环境因子影响不大。90、136.5、138和488bp等T-RFs可能代表了东平湖沉积物中占优势地位的土著菌群。通过Phylogenetic Assignment Tool在线分析结果推测,东平湖沉积物中的优势菌群可能属于Firmicutes和Proteobacteria门。【结论】环境因素对东平湖沉积物的细菌多样性产生显著影响,但对其土著菌群的影响不大。     

Temporal and spatial variations of aquatic environmental characteristics and sediment bacterial community in five regions of Lake Taihu

Sediment bacterial community and their relation with environmental factors were investigated in the five different trophic status lake regions sediment, Meiliang Bay, Wuli Lake, Gonghu Bay, Western Lake Taihu and Xukou Bay in a large, shallow, eutrophic freshwater lake (Lake Taihu, China). Water and surface sediment samples were collected at 35 sampling sites in January 2014 (winter) and July 2015 (summer). The physicochemical characterization showed that there were obvious changes in the trophic status and eutrophic index of five lake regions, which was mainly due to the difference of organic matter source. Based on the analysis of aquatic environmental characteristics, the organic nitrogen or nitrate nitrogen was the main storing form in the overlying water of five lake regions. In addition, nitrate nitrogen in pore water was lower than in overlying water, while ammonia nitrogen in pore water was higher than in overlying water. According to the DGGE profiles, temporal and spatial variations of bacterial community were apparent. Bacterial diversity was higher in summer than in winter and increased with the decrease in the lake region trophic status. The dendrogram of the bacterial community similarities revealed that samples were almost all grouped into two defined clusters (summer and winter), which indicated that season rather than region was the dominant factor. Canonical correspondence analysis demonstrated that ammonia nitrogen and nitrate–nitrite nitrogen in the sediment and pore water, organic matter and temperature significantly influenced the sediment bacterial community in the five lake regions.     

BIOCHEMISTRY OF CEREBRAL TUMOURS: SODIUM, POTASSIUM, CALCIUM, PHOSPHORUS, MAGNESIUM, COPPER AND SULPHUR CONTENTS OF ASTROCYTOMATA, MEDULLOBLASTOMATA AND GLIOBLASTOMATA MULTIFORME

Abstract— Twenty-nine autopsy specimens of intracerebral tumours (nine astrocytomata, ten medulloblastomata and ten glioblastomata multiforme), as well as samples of peritumoral and apparently normal brain tissue, have been studied for Na, K, P, Ca, Mg, Cu, and S contents.
The tumour tissue, irrespective of the histological characteristics, as compared to the 'normal' and perineoplastic tissues, showed higher concentration of Ca, Mg, Cu and S. The peritumoral tissue, regardless of the tumour type, showed a higher concentration of Cu than the 'normal' control brain.
The more malignant glioblatomata and medulloblastomata. The Cu levels did not show a significant diference.