Inhibitory action of elemental sulphur (S°) on fungal spores

1993 ◽  
Vol 39 (8) ◽  
pp. 731-735 ◽  
Author(s):  
Trello Beffa
Keyword(s):  
Neurospora Crassa ◽  
Fungal Spores ◽  
Final Concentration ◽  
Elemental Sulphur ◽  
Atp Content ◽  
High Concentration ◽  
Fungicidal Action ◽  
Low Concentrations ◽  
Production Of Hydrogen ◽  
Sulphydryl Groups

The fungitoxic effect of increasing concentrations of elemental sulphur (S°) was studied during the pregermination period of spores of Phomopsis viticola and conidia of Neurospora crassa. High concentrations of S° (> 10 μM final concentration) inhibited respiratory activities strongly and decreased the ATP content of spores and conidia. S° at low concentrations (1 and 3 μM final concentration) did not inhibit the respiratory activities or ATP content of spores and conidia. In spores of P. viticola, low concentrations of S° were reduced by the cells with the production of hydrogen sulphide (H2S), principally at the level of the respiratory chain. However, in the presence of a high concentration of S°, the capacity to reduce S° increased, and was then most probably independent of the respiratory activities. Proteic and nonproteic sulphydryl groups important in cellular metabolism were probably responsible for almost all the reduction of S°. In fact, the addition of increasing concentrations of S° to spores of P. viticola resulted in a dramatic increase in oxidized glutathione, suggesting the participation of reduced glutathione in S° reduction. In conclusion, we suggest that the fungicidal action of S° is probably related to the oxidation of important sulphydryl groups and not to the competitive interaction between S° and oxygen at the level of the respiratory chain.Key words: elemental sulphur, fungicide, fungi, Neurospora crassa, Phomospis viticola.

Metabolism of elemental sulphur (S°) during fungal spore germination

1993 ◽  
Vol 39 (8) ◽  
pp. 736-741 ◽  
Author(s):  
Trello Beffa
Keyword(s):  
Amino Acids ◽  
Neurospora Crassa ◽  
Fungal Spore ◽  
Mitochondrial Respiratory Chain ◽  
Final Concentration ◽  
Elemental Sulphur ◽  
Phomopsis Viticola ◽  
Free Sulphur ◽  
Sulphur Amino Acids ◽  
Layer Chromatography

35S-labelled elemental sulphur (S°) at nontoxic levels (3 μM) was incorporated into sulphur amino acids and glutathione by the spores of the fungus Phomopsis viticola. Incorporation studies were performed with 3 μM 35S° during the pregermination period of P. viticola spores. The free sulphur amino acids and protein sulphur amino acids were purified by column and thin-layer chromatography. During the first minutes of the pregermination process of the spores, the S° was essentially metabolized into free cysteine and glutathione. Detectable concentrations of methionine and homocysteine were measured after 1 h of incubation. Azide (2 mM final concentration), an inhibitor of the mitochondrial respiratory chain at the level of cytochrome oxidase, strongly inhibited the incorporation of S°. In contrast, the uncoupler 2,4-dinitrophenol (15 μM final concentration) and sulphate did not affect the incorporation of S°. The metabolism of 35S° into the protein sulphur amino acids cysteine and methionine during the germination of spores of P. viticola and conidia of Neurospora crassa is also discussed. It appears that S° does not necessarily have to be oxidized to sulphate prior to its incorporation into sulphur amino acids, but could be directly reduced to sulphide at the level of the respiratory chain.Key words: elemental sulphur, assimilation, sulphur amino acids, Phomopsis viticola, Neurospora crassa.

Biological Mechanisms of H2S Formation in Sewer Pipes

1992 ◽  
Vol 26 (3-4) ◽  
pp. 907-914 ◽  
Author(s):  
A. Attal ◽  
M. Brigodiot ◽  
P. Camacho ◽  
J. Manem
Keyword(s):  
Suspended Solid ◽  
Urban Wastewater ◽  
Biological Mechanisms ◽  
Sewer Pipes ◽  
Sulfate Reducing ◽  
Biological Phenomena ◽  
Low Concentrations ◽  
Production Of Hydrogen ◽  
High Concentrations ◽  
Reducing Bacteria

The purpose of this study is to gain a better understanding of the biological phenomena involved in the production of hydrogen sulfide in urban wastewater (UWW) systems. It is found that the UWW itself naturally possesses the biomass needed to consume the sulfates. These heterotrophic sulfate-reducing bacteria populations, though immediately active in strict anaerobic conditions, are present only in very low concentrations in the UWW. A concentration of them was studied within the pressure pipes, in the form of deposits, and this justifies the high concentrations of sulfides measured in certain wastewater networks. There are two reasons why the ferrous sulfate used as a treatment in any wastewater networks should not cause the production of additional sulfides. Firstly, the sulfate consumption kinetics are always too slow, relative to the residence time of the water in the pipe, for all of the sulfates to be consumed anyway. Secondly, the amount of assimilable carbon, soluble carbon, and carbon from suspended solid (SS) hydrolysis is insufficient.

Small-volume vitrification and rapid warming yield high survivals of one-cell rat embryos in cryotubes

2021 ◽  
Author(s):  
Yasuyoshi Fukuda ◽  
Misako Higashiya ◽  
Takahiro Obata ◽  
Keita Basaki ◽  
Megumi Yano ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Small Volume ◽  
Sucrose Solution ◽  
High Concentration ◽  
Rat Embryos ◽  
Low Concentrations ◽  
Intracellular Ice Formation ◽  
Intracellular Ice ◽  
Warming Rate ◽  
Very High

Abstract To cryopreserve cells, it is essential to avoid intracellular ice formation during cooling and warming. One way to achieve this is to convert the water inside the cells into a non-crystalline glass. It is currently believed that to accomplish this vitrification, the cells must be suspended in a very high concentration (20–40%) of a glass-inducing solute, and subsequently cooled very rapidly. Herein, we report that this belief is erroneous with respect to the vitrification of one-cell rat embryos. In the present study, one-cell rat embryos were vitrified with 5 μL of EFS10 (a mixture of 10% ethylene glycol, 27% Ficoll, and 0.45 M sucrose) in cryotubes at a moderate cooling rate, and warmed at various rates. Survival was assessed according to the ability of the cells to develop into blastocysts and to develop to term. When embryos were vitrified at a 2,613 °C/min cooling rate and thawed by adding 1 mL of sucrose solution (0.3 M, 50 °C) at a warming rate of 18,467 °C/min, 58.1 ± 3.5% of the EFS10-vitrified embryos developed into blastocysts, and 50.0 ± 4.7% developed to term. These rates were similar to those of non-treated intact embryos. Using a conventional cryotube, we achieved developmental capabilities in one-cell rat embryos by rapid warming that were comparable to those of intact embryos, even using low concentrations (10%) of cell-permeating cryoprotectant and at low cooling rates.

Drosophila cell fusion induced by wheat germ agglutinin

1975 ◽  
Vol 18 (1) ◽  
pp. 113-121
Author(s):  
R.M. Rizki ◽  
T.M. Rizki ◽  
C.A. Andrews
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Embryonic Cell ◽  
High Concentration ◽  
Drosophila Cell ◽  
Low Concentrations ◽  
Embryonic Cell Lines ◽  
Scanning Electron

The effects of wheat germ agglutinin on Drosophila embryonic cell lines growing on cover-glasses was examined by scanning electron microscopy. At low concentrations of the lectin (5-10 mug/ml), cells spread against the glass surface and fused to form syncytia. At high concentration, damage to the cell surface was evidenced as extensive membrane shrivelling and loss of surface microfilaments. Fusion also occurred under these conditions. There was some indication that the morphology of cells in division remains undisturbed by wheat germ agglutinin. The coalescence of cells and morphologic disotrtion induced by wheat germ agglutinin were not inhibited by N-acetylglucosamine, the hapten inhibitor of the lectin, under the conditions utilized in this study.

scholarly journals Blooms of bryozoans and epibenthic diatoms in an urbanized sandy Beach (Balneário Camboriú - SC - Brazil): dynamics, possible causes and biomass characterization

2017 ◽  
Vol 65 (4) ◽  
pp. 678-694 ◽  
Author(s):  
Leonardo Rubi Rörig ◽  
Maevi Ottonelli ◽  
Ana Gabriela Itokazu ◽  
Marcelo Maraschin ◽  
João Vitor Heberle Lins ◽  
...  
Keyword(s):  
Saturated Fatty Acids ◽  
Experimental Studies ◽  
Growth Conditions ◽  
Adjacent Area ◽  
High Concentration ◽  
Local Pollution ◽  
Organic Debris ◽  
Quality Of Water ◽  
Low Concentrations ◽  
Environmental Health Problem

Abstract Balneário Camboriu (SC - Brazil) is a touristic city where the disordered growth of the urban population and the implementation of coastal works without proper evaluation generated environmental impacts and affected the sanitary quality of water and sediment of Camboriu River and marine adjacent area. One of the most recent and alarming phenomena observed are the blooms of invasive bryozoans (Arboscuspis bellula and Membraniporopsis tubigera) associated with epibenthic diatoms (Amphitetras antediluviana and Biddulphia biddulphiana). Several clues associate these phenomena, started in 2003, with the excess of nutrients and organic matter in the Camboriú cove and large coastal works such as dredging, landfills and construction of jetties, leading to changes in benthic ecological structure. Being an aesthetic and environmental health problem, the concern of the scientific community and government agencies intensified as the occurrences become more frequent and persistent. This research addresses this issue through environmental and experimental studies. Samplings of the benthic material collected by boat and diving, and blooms monitoring were the environmental approach. The laboratory work included the algal isolation and culture, in addition to growth conditions assessment and chemical biomass analysis. Monitoring data showed a seasonal trend in the blooms, with more conspicuous events in warmer months. Diatoms increase in abundance in colder months and bryozoans in the warmer ones. The diatom A. antediluviana, predominant in the blooms, grew satisfactorily in laboratory cultivation, showing better growth in media with higher concentrations of silicate and phosphate. Bryozoans showed slow growth in laboratory conditions. The deposited material collected in the environment showed low concentrations of saturated fatty acids, but the high biomass suggest a possible use for biofuels production. Biomass samples dominated by bryozoans showed moderate antimicrobial activity against Klebsiella pneumoniae. The explanation for the occurrence of these blooms are still inconclusive, but there is considerable evidence that it is a synergistic effect between the high concentration of bacteria and organic debris in the water related to local pollution and the elimination of natural competitors by coastal works.

scholarly journals Effects of Bacterial Cell-Free Supernatant on Nutritional Parameters of Apis Mellifera and Their Toxicity Against Varroa Destructor

2020 ◽  
Vol 64 (1) ◽  
pp. 55-66
Author(s):  
Fiorella G. De Piano ◽  
Matias D. Maggi ◽  
Facundo R. Meroi Arceitto ◽  
Marcela C. Audisio ◽  
Martín Eguaras ◽  
...  
Keyword(s):  
Apis Mellifera ◽  
Varroa Destructor ◽  
High Concentration ◽  
Colony Losses ◽  
Nutritional Parameters ◽  
Low Concentrations ◽  
Bee Health ◽  
Contact Exposure ◽  
Fat Bodies ◽  
The Relationship

AbstractApis mellifera L. is an essential pollinator that is currently being affected by several stressors that disturb their ecological function and produce colony losses. Colonies are being seriously affected by the ectoparasitic mite Varroa destructor. The relationship between stressors and bee symbionts is being studied in order to enhance bee health. The goal of this study was to evaluate the effect of cell-free supernatants (CFSs) produced by Lactobacillus johnsonii AJ5, Enterococcus faecium SM21 and Bacillus subtilis subsp. subtilis Mori2 on A. mellifera nutritional parameters and their toxicity against V. destructor. Toxicity and survival bioassays were conducted on adult bees with different concentrations of CFSs. Nutritional parameters such as soluble proteins and fat bodies in abdomens were measured. Varroa destructor toxicity was analyzed by a contact exposure method and via bee hemolymph. At low concentrations, two of CFSs tends to enhance bee survival. Remarkably fat bodies maintained their levels with all CFS concentrations in the abdomens, and soluble protein increased at a high concentration of two CFSs. Toxicity against V. destructor was observed only via hemolymph, and results were in agreement with the treatment that produced an increase in bee proteins. Finally, CFS produced by L. johnsonii AJ5 could be a promising natural alternative for strengthening bee health.

scholarly journals Sexual dimorphism in prostacyclin-mimetic responses of rat mesenteric and coronary arteries.

2021 ◽  
Author(s):  
Samuel Baldwin ◽  
Elizabeth Forrester ◽  
Lauren McEwan ◽  
Iain Greenwood
Keyword(s):  
Experimental Approach ◽  
Mesenteric Arteries ◽  
High Concentration ◽  
Male And Female ◽  
Sexual Dimorphisms ◽  
Kv7 Channels ◽  
Low Concentrations ◽  
Ip Receptor ◽  
Female Wistar Rats ◽  
Arterial Tone

Background and purpose- Prostacyclin mimetics are widely used clinically. As such it is pertinent to understand the mechanisms underlying the vasoactive response to such agents, yet to date, no study has considered sex as a factor. The aim of this study was to characterise the effect of prostacyclin mimetics, Iloprost and MRE-269, on precontracted arterial tone from male and female Wistar arteries. As a secondary consideration, we investigated Kcnq-encoded KV7 channels as potential downstream targets of prostacyclin-IP-receptor mediated signalling. Experimental approach- Relative mRNA transcript and protein abundance were determined by RT-qPCR and immunocytochemistry respectively. The effect of Iloprost and MRE-269 was determined on pre-contracted arterial tone in the presence of pharmacological modulators of potassium channels and molecular interreference of KV7.1 within 2nd order mesenteric and left anterior descending arteries from male and female Wistar rats. Key results- Iloprost evoked a bi-phasic response in male mesenteric arteries, at low concentrations relaxing, then contracting the vessel at high concentration in a process attributed to IP and EP3 receptors respectively. Secondary contraction was absent in the females, potentially underpinned by a reduction in Ptger3. Pharmacological inhibition and molecular interference of KV7.1 significantly attenuated MRE-269 mediated relaxation in male and female Wistar in Diestrus / Metoestrous, but not Pro-oestrus / Oestrus. Conclusions and implications- Stark sexual dimorphisms in Iloprost mediated vasoactive responses are present within mesenteric arteries. KV7.1 is implicated in IP-receptor mediated vasorelaxation and is impaired by the Oestrus cycle.

Modelling of microbial processes that govern degradation of organic substrates in soil, with special reference to pesticides

1990 ◽  
Vol 329 (1255) ◽  
pp. 369-373 ◽  
Keyword(s):  
Microbial Population ◽  
Large Fraction ◽  
Organic Substrates ◽  
High Concentration ◽  
Deterministic Models ◽  
Soil Microbial ◽  
Low Concentrations ◽  
Biokinetic Parameters ◽  
Soil Microbial Population ◽  
Kinetics Of

We tried to develop deterministic models for kinetics of 2,4-D breakdown in the soil based on the following considerations: (i) at low concentrations degradation results from maintenance consumption by a large fraction of the soil microbial population; (ii) at high concentration in addition to the maintenance consumption there is a growth-associated carbon incorporation by a small specific microbial population. Values for the biokinetic parameters are consistent with those commonly found in the literature. Comparison between observed and simulated curves suggests that a non-negligible part of the pesticidal carbon exists as microbial by-products.

Hydrogen Interaction with Defects in ZnO

2012 ◽  
Vol 733 ◽  
pp. 228-231 ◽  
Author(s):  
František Lukáč ◽  
Jakub Čížek ◽  
Marián Vlček ◽  
Ivan Procházka ◽  
Martin Vlach ◽  
...  
Keyword(s):  
Subsurface Layer ◽  
Positron Annihilation Spectroscopy ◽  
Nuclear Reaction Analysis ◽  
X Ray Diffraction ◽  
High Concentration ◽  
X Ray ◽  
Low Concentrations ◽  
Hydrogen Interaction ◽  
Induced Stresses ◽  
Zno Crystal

In the present work hydrothermally grown ZnO single crystals were electrochemically charged with hydrogen. The influence of hydrogen on ZnO microstructure was investigated by positron annihilation spectroscopy (PAS) combined with X-ray diffraction (XRD) using synchrotron radiation. Hydrogen concentration in the samples was determined by nuclear reaction analysis (NRA). It was found that a high concentration of hydrogen can be introduced into ZnO by electrochemical loading. At low concentrations, absorbed hydrogen causes elastic volume expansion of ZnO crystal. At higher concentration, hydrogen-induced stresses exceed the yield stress in ZnO and plastic deformation of the crystal takes place leading to formation of a defected subsurface layer in the crystals.

Improved XLT4 Agar: Small Addition of Peptone to Promote Stronger Production of Hydrogen-Sulfide by Salmonellae

1994 ◽  
Vol 57 (10) ◽  
pp. 854-858 ◽  
Author(s):  
R. G. MILLER ◽  
C. R. TATE ◽  
E. T. MALLINSON
Keyword(s):  
Hydrogen Sulfide ◽  
Clinical Samples ◽  
Pork Sausage ◽  
Bacterial Cultures ◽  
Proteose Peptone ◽  
Low Concentrations ◽  
Production Of Hydrogen ◽  
Hydrogen Sulfide Production ◽  
Selective Plating ◽  
Pure Bacterial Cultures

Xylose lysine tergitol4 agar (XLT4) is a highly selective plating medium used for isolating salmonellae. Studies have shown that XLT4 increases the recovery of salmonellae found in food, environmental and clinical samples. Further testing demonstrated that the addition of low concentrations of proteose peptone No. 3 (pp3) to XLT4 produced blacker Salmonella colonies in shorter incubation times (increased hydrogen sulfide production), while still maintaining strong inhibition of competing bacteria. The increased black colony formation facilitates prompt recognition of the weaker hydrogen sulfide-producing Salmonella strains. Test concentrations of pp3 at 0.5, 1.2 and 1.8 g/L were added to XLT4 and compared with plain XLT4 using pure bacterial cultures. In addition, these four plating media, plus xylose lysine desoxycholate agar (XLD) were evaluated using nonspiked chicken liver and pork sausage samples. The concentration of 1.2 g/L of pp3 in XLT4 gave the best overall results. In virtually all cases, the Salmonella colonies were larger and more black than on plain XLT4 without pp3. The improved XLT4 is recommended for more reliable detection of salmonellae from food, environmental and clinical samples.

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