A study of field drain ochre deposits. 2. The distribution of micro-organisms

1987 ◽  
Vol 108 (2) ◽  
pp. 347-351 ◽  
Author(s):  
I. Ap Dbwi ◽  
D. B. Johnson ◽  
W. I. Kelso
Keyword(s):  
Thiobacillus Ferrooxidans ◽  
Heterotrophic Bacteria ◽  
Drainage Water ◽  
Low Ph ◽  
Filamentous Bacteria ◽  
England And Wales ◽  
Neutral Ph ◽  
Wide Range ◽  
Water Ph ◽  
Micro Organisms

SummarySheathed filamentous bacteria,Leptothrixspp. andGallionellaspp., were observed in ochre samples from sites in England and Wales.Thiobacillus ferrooxidanswas found in acidic samples (pH < 4·0) and in ochre from drainage water of near neutral pH suggesting that it can contribute to ochre formation over a wide range of drainage water pH, Heterotrophic bacteria capable of growing in artificial media of low pH and complexdegrading heterotrophic bacteria were also isolated. Some ochre deposits could be described as either pyritic or filamentous but the majority of samples fell between these extremes and had various combinations ofT. ferrooxidans, sheathed filamentous bacteria and other heterotrophic bacteria.

Effects of Aluminum on the Leopard Frog, Rana pipiens: Life Stag Comparisons and Aluminum Uptake

1990 ◽  
Vol 47 (1) ◽  
pp. 210-216 ◽  
Author(s):  
Joseph Freda ◽  
D. Gordon McDonald
Keyword(s):  
Rana Pipiens ◽  
Low Ph ◽  
The Body ◽  
Leopard Frog ◽  
Whole Body ◽  
Toxicity Tests ◽  
Al Content ◽  
Wide Range ◽  
Water Ph ◽  
Percent Mortality

In this study, we conducted a series of toxicity tests investigating the response of embryos, prestage 25 tadpoles and 3-wk old tadpoles of the leopard frog (Rana pipiens) to a wide range pf pH (4.2–4.8) and Al (0–1000 μg∙:L−1}, and to pH 6.5 with no Al present. In embryos and prestage 25 tadpoles, Al ameliorated the toxic effects of very low pH's (4.2–4.4), while becoming toxic at higher pH's (4.6–4.8). Although both embryos and prestage 25 tadpoles were killed by low pH (pH 4.2–4.4 and 4.2, respectively) and elevated Al ([Formula: see text] and [Formula: see text] Al, respectively), embryos were relatively more sensitive (i.e. higher percent mortality) to low pH, whereas prestage 25 tadpoles were relatively more sensitive to Al Three week old tadpoles did not die at any test pH (without Al) and mortality (>20%) caused by Al occurred at only pH 4.8 and 750–1000 μg∙L−1 Al. The body sodium concentrations of 3-wk old tadpoles that survived high Al exposure were depressed indicating sublethal stress. Whole body Al uptake in 3-wk old tadpoles was also elevated in water containing high concentrations of Al, but it was positively related to water pH and exposure time. This result suggests that body Al content is not an accurate indicator of Al exposure in tadpoles living in acidic, Al contaminated ponds.

scholarly journals Vaccinia Virus Entry into Cells via a Low-pH-Dependent Endosomal Pathway

2006 ◽  
Vol 80 (18) ◽  
pp. 8899-8908 ◽  
Author(s):  
Alan C. Townsley ◽  
Andrea S. Weisberg ◽  
Timothy R. Wagenaar ◽  
Bernard Moss
Keyword(s):  
Plasma Membrane ◽  
Vaccinia Virus ◽  
Virus Entry ◽  
Low Ph ◽  
Neutral Ph ◽  
Concanamycin A ◽  
Endosomal Acidification ◽  
Wide Range ◽  
Endosomal Pathway ◽  
Ph Dependent

ABSTRACT Previous studies established that vaccinia virus could enter cells by fusion with the plasma membrane at neutral pH. However, low pH triggers fusion of vaccinia virus-infected cells, a hallmark of viruses that enter by the endosomal route. Here, we demonstrate that entry of mature vaccinia virions is accelerated by brief low-pH treatment and severely reduced by inhibitors of endosomal acidification, providing evidence for a predominant low-pH-dependent endosomal pathway. Entry of vaccinia virus cores into the cytoplasm, measured by expression of firefly luciferase, was increased more than 10-fold by exposure to a pH of 4.0 to 5.5. Furthermore, the inhibitors of endosomal acidification bafilomycin A1, concanamycin A, and monensin each lowered virus entry by more than 70%. This reduction was largely overcome by low-pH-induced entry through the plasma membrane, confirming the specificities of the drugs. Entry of vaccinia virus cores with or without brief low-pH treatment was visualized by electron microscopy of thin sections of immunogold-stained cells. Although some virus particles fused with the plasma membrane at neutral pH, 30 times more fusions and a greater number of cytoplasmic cores were seen within minutes after low-pH treatment. Without low-pH exposure, the number of released cores lagged behind the number of virions in vesicles until 30 min posttreatment, when they became approximately equal, perhaps reflecting the time of endosome acidification and virus fusion. The choice of two distinct pathways may contribute to the ability of vaccinia virus to enter a wide range of cells.

scholarly journals Interactions between Sponges and the Water Column:  Nutrient Utilisation and Feeding by New Zealand  Subtidal Sponges

2021 ◽  
Author(s):  
◽  
Alejandra Perea-Blázquez
Keyword(s):  
New Zealand ◽  
Water Column ◽  
Heterotrophic Bacteria ◽  
Marine Ecosystems ◽  
Sponge Species ◽  
Suspension Feeders ◽  
Functional Roles ◽  
Nutrient Utilisation ◽  
Wide Range ◽  
Micro Organisms

<p>Sponges are an important component of New Zealand subtidal communities and play many key functional roles in marine ecosystems, including competition for space, facilitating primary production, nutrient cycling, bioerosion, and interactions with the water column. Sponges are involved in the bidirectional movement of detritus, nutrients, micro-organisms and planktonic particles both to and from the benthos to the pelagic ecosystem, thereby affecting pelagic processes. As suspension-feeders, sponges are capable of filtering large volumes of water, and they depend on food that is suspended in the water column, meaning that their interaction with the water column is likely to be very important. The main goal of my research was to investigate the interactions between sponges and the water column and how this varies in relation to sponge characteristics, nutrient fluxes, seasonality and food supply. I studied the diet composition of 10 sponge species that are abundant and widely distributed along the south coast of Wellington, New Zealand. I found that the diet of the sponge species analysed comprised three types of picoplanktonic organisms: heterotrophic bacteria, Prochlorococcus, and Synechococcus. These micro-organisms (picoplankton) that sponges feed on are vital for benthic food webs because they are involved in the transformation and cycling process of dissolved inorganic nutrients before they become available to other marine organisms. The results from this thesis demonstrated that different sponge species have different retention efficiencies for different types of picoplankton and I propose that this suggests intra-phyletic food particle niche partitioning among sponges. While these findings support the partitioning of food resources between different co-existing sponge species, they also suggest that partitioning may not be essential for co-existence, as some species had similar retention efficiencies implying an overlap in resource use. By measuring rates of carbon assimilation in the form of planktonic food particles, combined with data on a number of characteristics of the sponge species analysed, I found that sponge assemblages play a key role in the transfer of energy from the water column to the benthos. The results from this thesis indicate that there is a wide range of food concentrations in the rocky reefs where the study species are living, over which retention rate, nutrient utilisation and carbon consumption varied temporally. This emphasises the importance of understanding temporal variation in productivity, and suggests that such variations are likely to have important implications for suspension-feeders. By integrating the feeding results with estimations of oxygen consumption rates, and the amount of carbon obtained from the different micro-organisms found in the water column, preliminary carbon budgets were created. These budgets were used to quantify the capacity of carbon obtained via heterotrophic suspension-feeding to support sponge metabolism, as well as infer the potential for this carbon to support other processes such as sponge growth and reproduction. Overall, this project was the first to consider the functional roles of sponges in New Zealand marine ecosystems and provided useful information on their ecological and biological importance. The large amounts of carbon that sponges transfer from the water column to the benthos, in conjunction with the other findings of my thesis, increase our understanding of the ecology of temperate sponges.</p>

scholarly journals Interactions between Sponges and the Water Column:  Nutrient Utilisation and Feeding by New Zealand  Subtidal Sponges

2021 ◽  
Author(s):  
◽  
Alejandra Perea-Blázquez
Keyword(s):  
New Zealand ◽  
Water Column ◽  
Heterotrophic Bacteria ◽  
Marine Ecosystems ◽  
Sponge Species ◽  
Suspension Feeders ◽  
Functional Roles ◽  
Nutrient Utilisation ◽  
Wide Range ◽  
Micro Organisms

<p>Sponges are an important component of New Zealand subtidal communities and play many key functional roles in marine ecosystems, including competition for space, facilitating primary production, nutrient cycling, bioerosion, and interactions with the water column. Sponges are involved in the bidirectional movement of detritus, nutrients, micro-organisms and planktonic particles both to and from the benthos to the pelagic ecosystem, thereby affecting pelagic processes. As suspension-feeders, sponges are capable of filtering large volumes of water, and they depend on food that is suspended in the water column, meaning that their interaction with the water column is likely to be very important. The main goal of my research was to investigate the interactions between sponges and the water column and how this varies in relation to sponge characteristics, nutrient fluxes, seasonality and food supply. I studied the diet composition of 10 sponge species that are abundant and widely distributed along the south coast of Wellington, New Zealand. I found that the diet of the sponge species analysed comprised three types of picoplanktonic organisms: heterotrophic bacteria, Prochlorococcus, and Synechococcus. These micro-organisms (picoplankton) that sponges feed on are vital for benthic food webs because they are involved in the transformation and cycling process of dissolved inorganic nutrients before they become available to other marine organisms. The results from this thesis demonstrated that different sponge species have different retention efficiencies for different types of picoplankton and I propose that this suggests intra-phyletic food particle niche partitioning among sponges. While these findings support the partitioning of food resources between different co-existing sponge species, they also suggest that partitioning may not be essential for co-existence, as some species had similar retention efficiencies implying an overlap in resource use. By measuring rates of carbon assimilation in the form of planktonic food particles, combined with data on a number of characteristics of the sponge species analysed, I found that sponge assemblages play a key role in the transfer of energy from the water column to the benthos. The results from this thesis indicate that there is a wide range of food concentrations in the rocky reefs where the study species are living, over which retention rate, nutrient utilisation and carbon consumption varied temporally. This emphasises the importance of understanding temporal variation in productivity, and suggests that such variations are likely to have important implications for suspension-feeders. By integrating the feeding results with estimations of oxygen consumption rates, and the amount of carbon obtained from the different micro-organisms found in the water column, preliminary carbon budgets were created. These budgets were used to quantify the capacity of carbon obtained via heterotrophic suspension-feeding to support sponge metabolism, as well as infer the potential for this carbon to support other processes such as sponge growth and reproduction. Overall, this project was the first to consider the functional roles of sponges in New Zealand marine ecosystems and provided useful information on their ecological and biological importance. The large amounts of carbon that sponges transfer from the water column to the benthos, in conjunction with the other findings of my thesis, increase our understanding of the ecology of temperate sponges.</p>

Bioencapsulation in Sol-Gel Glasses

1998 ◽  
Vol 519 ◽  
Author(s):  
L. Bergogne ◽  
S. Fennouh ◽  
J. Livage ◽  
C. Roux
Keyword(s):  
Sol Gel ◽  
Porous Silica ◽  
Silica Matrix ◽  
Whole Cells ◽  
The Past ◽  
Wide Range ◽  
Activity Of Enzymes ◽  
Gel Glasses ◽  
Micro Organisms

AbstractBioencapsulation in sol-gel materials has been widely studied during the past decade. Trapped species appear to retain their bioactivity in the porous silica matrix. Small analytes can diffuse through the pores allowing bioreactions to be performed in-situ, inside the sol-gel glass. A wide range of biomolecules and micro-organisms have been encapsulated. The catalytic activity of enzymes is used for the realization of biosensors or bioreactors. Antibody-antigen recognition has been shown to be feasible within sol-gel matrices. Trapped antibodies bind specifically the corresponding haptens and can be used for the detection of traces of chemicals. Even whole cells are now encapsulated without any alteration of their cellular organization. They can be used for the production of chemicals or as antigens for immunoassays.

scholarly journals Diphtheria toxin entry into cells is facilitated by low pH.

1980 ◽  
Vol 87 (3) ◽  
pp. 828-832 ◽  
Author(s):  
K Sandvig ◽  
S Olsnes
Keyword(s):  
Protein Synthesis ◽  
Toxic Effect ◽  
Diphtheria Toxin ◽  
Surface Membrane ◽  
Low Ph ◽  
Toxin A ◽  
Neutral Ph ◽  
Diphtheria Toxin A ◽  
Adsorptive Endocytosis

At neutral pH, NH4Cl and chloroquine protected cells against diphtheria toxin. A brief exposure of the cells to low pH (4.5-5.5) at 37 degrees completely abolished this protection. When, to cells preincubated with diphtheria toxin and NH4Cl, neutralizing amounts of anti-diphtheria toxin were added before the pH was lowered, the toxic effect was considerably reduced, but it was not completely abolished. A much stronger toxic effect was seen when antibodies were added immediately after incubation at low pH. Upon a short incubation with diphtheria toxin at low pH, the rate of protein synthesis in the cells decreased much faster than when the normal pH was maintained. The data suggest that, at low pH, diphtheria toxin (or its A fragment) penetrates directly through the surface membrane of the cell. The possibility is discussed that, when the medium has a neutral pH, the entry of diphtheria toxin involves adsorptive endocytosis and reduction of the pH in the vesicles possibly by fusion with lysosomes. Low pH did not facilitate the entry of the closely related toxins abrin, ricin, and modeccin.

Motion of slender bodies in unsteady Stokes flow

2011 ◽  
Vol 688 ◽  
pp. 66-87 ◽  
Author(s):  
Efrath Barta
Keyword(s):  
Stokes Flow ◽  
Slenderness Ratio ◽  
Creeping Flow ◽  
Slender Body Theory ◽  
Wide Range ◽  
Unsteady Stokes Flow ◽  
Slender Bodies ◽  
Set Up ◽  
Micro Organisms ◽  
Parameter Values

AbstractThe flow regime in the vicinity of oscillatory slender bodies, either an isolated one or a row of many bodies, immersed in viscous fluid (i.e. under creeping flow conditions) is studied. Applying the slender-body theory by distributing proper singularities on the bodies’ major axes yields reasonably accurate and easily computed solutions. The effect of the oscillations is revealed by comparisons with known Stokes flow solutions and is found to be most significant for motion along the normal direction. Streamline patterns associated with motion of a single body are characterized by formation and evolution of eddies. The motion of adjacent bodies results, with a reduction or an increase of the drag force exerted by each body depending on the direction of motion and the specific geometrical set-up. This dependence is demonstrated by parametric results for frequency of oscillations, number of bodies, their slenderness ratio and the spacing between them. Our method, being valid for a wide range of parameter values and for densely packed arrays of rods, enables simulation of realistic flapping of bristled wings of some tiny insects and of locomotion of flagella and ciliated micro-organisms, and might serve as an efficient tool in the design of minuscule vehicles. Its potency is demonstrated by a solution for the flapping of thrips.

Phytophthora nicotianae var. parasitica. [Descriptions of Fungi and Bacteria].

1964 ◽  
Author(s):  
G. M. Waterhouse
Keyword(s):  
Geographical Distribution ◽  
Citrus Fruit ◽  
Heavy Rain ◽  
Drainage Water ◽  
Phytophthora Nicotianae ◽  
Crown Rot ◽  
Fruit Rot ◽  
Piper Betle ◽  
Wide Range ◽  
Southern Rhodesia

Abstract A description is provided for Phytophthora nicotianae var. parasitica. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On a very wide range of host plants comprising 58 families including: avocado, castor, Cinchona spp., citrus, cotton, eggplant, guava, lucerne, papaw, parsley, pineapple, Piper betle, rhubarb, sesame, strawberry, tomato. DISEASES: Damping-off of seedlings (tomato, castor, citrus, cotton); root rot (citrus, avocado, strawberry, lucerne); crown rot (parsley, rhubarb, strawberry, lucerne); brown stem rot of tobacco; stem canker and tip blight of Cinchona spp. ; leaf blight (castor, sesame, pineapple, Piper betle) and fruit rot (citrus, tomato, guava, papaw, eggplant). GEOGRAPHICAL DISTRIBUTION: Africa (Ethiopia, Mali, Madagascar, Mauritius, Morocco, Nigeria, Sierra Leone, Southern Rhodesia, Tanganyika); Asia (Burma, Ceylon, China, Formosa, India, Israel, Japan, Java, Malaya, Philippines); Australia & Oceania (Australia, Hawaii, Tasmania); Europe (Cyprus, France, Germany, Great Britain, Holland, Ireland, Italy, Poland, Portugal, U.S.S.R.); North America (Bermuda, Canada, Mexico, U.S.A.); Central America & West Indies (Costa Rica, Cuba, El Salvador, Guatemala, Jamaica, Montserrat, Puerto Rico, Trinidad);. South America (Argentina, Brazil, British Guiana, Colombia, Paraguay, Peru, Venezuela). TRANSMISSION: Soil-borne, spreading rapidly after heavy rain or where soil remains moist or water-logged (40: 470). Also recorded in drainage water in India and in reservoirs and canals supplying citrus groves in U.S.A. (23: 45; 39: 24). A method for determining a disease potential index in soil using lemon fruit has been described (38: 4). Also present in testas of seeds from diseased citrus fruit which may infect nursery seedbeds (37: 165).

scholarly journals Actinomycetes as An Environmental Scrubber

2021 ◽  
Author(s):  
Sutaria Devanshi ◽  
Kamlesh R. Shah ◽  
Sudipti Arora ◽  
Sonika Saxena
Keyword(s):  
Secondary Metabolites ◽  
Agricultural Waste ◽  
Chemical Compounds ◽  
Filamentous Bacteria ◽  
Primary And Secondary Metabolites ◽  
Sustainable Environment ◽  
Potential Source ◽  
Wide Range ◽  
Bioactive Secondary Metabolites ◽  
Broad Variety

Biotechnological tools engaged in the bioremediation process are in reality, sophisticated and dynamic in character. For specialized reasons, a broad variety of such devices are employed to produce a safe and balanced environment free of all types of toxins and so make life simpler for humans on planet Earth. Actinomycetes is one of these extremely important and functionally helpful groups. They can be used for a variety of bioremediation objectives, including biotransformation, biodegradation, and many more. Actinomycetes are one of the most varied groups of filamentous bacteria, capable of prospering in a variety of ecological settings because to their bioactive capabilities. They’re famous for their metabolic diversity, which includes the synthesis of commercially useful primary and secondary metabolites. They produce a range of enzymes capable of totally destroying all of the constituents. They are well-known for their ability to produce bioactive secondary metabolites. Members of various genera of Actinomycetes show promise for application in the bioconversion of underutilized urban and agricultural waste into high-value chemical compounds. The most potential source is a wide range of important enzymes, some of which are synthesized on an industrial scale, but there are many more that have yet to be discovered. Bioremediation methods, which use naturally existing microbes to clear residues and contaminated regions of dangerous organic chemicals, are improving all the time. In the realm of biotechnological science, the potential of actinomycetes for bioremediation and the synthesis of secondary metabolites has opened up intriguing prospects for a sustainable environment.

scholarly journals Analysis of virulence factors and emm typing of Streptococcus pyogenes clinical isolates.

2019 ◽  
Author(s):  
Gustavo Enck Sambrano ◽  
Gustavo P Riboldi ◽  
Keli C Reiter ◽  
Thiago Galvão da Silva Paim ◽  
Neidmar Correa Tolfo ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Streptococcus Pyogenes ◽  
Virulence Genes ◽  
Clinical Isolates ◽  
Pcr Analysis ◽  
Tissue Tropism ◽  
Factors Analysis ◽  
Wide Range ◽  
Group A ◽  
Micro Organisms

Background: Streptococcus pyogenes, a Group A streptococci (GAS), is an important human pathogen that causes a wide range of infections. Methods: Twenty five clinical isolates of S. pyogenes were submitted to an emm typing and to a Real-time PCR analysis for 23 important virulence factors. Results: Fourteen emm types were found and the emm1 type was the most prevalent. The majority of the isolates were classified as emm pattern E, followed by A-C3. No pattern D was found. Among the virulence factors, the most prevalent were SpeG, Slo, C5a-peptidase and SPNA. Phage encoded virulence genes were also found among the strains, such as mf-2, SpeJ and SpeL. Discussion: The emm1 type was the most prevalent while the 13 others M types were distributed along the strains. No tissue tropism was found on the isolates. The virulence factors analysis demonstrated that chromosomally and phage-encoded genes were found, which confers a potential for high virulent micro-organisms.

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