A technique for the study of oxygen availability to micro-organisms in soil and its possible use as an index of soil aeration

1947 ◽  
Vol 37 (3) ◽  
pp. 249-256 ◽  
Author(s):  
D. M. Webley
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Availability ◽  
Bacterial Cells ◽  
Experimental Conditions ◽  
Soil Aeration ◽  
Resultant Effect ◽  
Aeration Conditions ◽  
A New Technique ◽  
Micro Organisms ◽  
Properties Of Soil

1. In Part I of the paper details are presented of a new technique for the study of oxygen availability to bacteria added to soil. In essentials the technique consists of adding a washed suspension of bacterial cells together with excess of suitable oxidizable substrate to air dried, sieved soil contained in Warburg vessels. The rate of oxygen uptake is looked upon as a function of the aeration conditions within the soil. The results can be expressed by means of a conventional figure called the aeration factor (or A.F.).2. In Part II with the use of the technique it has been shown that two physical properties of soil which influence oxygen availability under the experimental conditions of the technique are (a) moisture content of the soil, (b) the amount of break-up of the soil crumbs. Since the A.F. measures the resultant effect produced by these factors it may be regarded as an index of soil aeration.

Electrochemical communication between microbial cells and electrodes via osmium redox systems

2012 ◽  
Vol 40 (6) ◽  
pp. 1330-1335 ◽  
Author(s):  
Kamrul Hasan ◽  
Sunil A. Patil ◽  
Dónal Leech ◽  
Cecilia Hägerhäll ◽  
Lo Gorton
Keyword(s):  
Electron Transfer ◽  
Biofuel Cells ◽  
Major Group ◽  
Electrochemical Biosensors ◽  
Bioelectrochemical Systems ◽  
Bacterial Cells ◽  
Redox Systems ◽  
Microbial Cells ◽  
Fundamental Part ◽  
Micro Organisms

Electrochemical communication between micro-organisms and electrodes is the integral and fundamental part of BESs (bioelectrochemical systems). The immobilization of bacterial cells on the electrode and ensuring efficient electron transfer to the electrode via a mediator are decisive features of mediated electrochemical biosensors. Notably, mediator-based systems are essential to extract electrons from the non-exoelectrogens, a major group of microbes in Nature. The advantage of using polymeric mediators over diffusible mediators led to the design of osmium redox polymers. Their successful use in enzyme-based biosensors and BFCs (biofuel cells) paved the way for exploring their use in microbial BESs. The present mini-review focuses on osmium-bound redox systems used to date in microbial BESs and their role in shuttling electrons from viable microbial cells to electrodes.

Hydrothermal Generation of 3-Dimensional WO3 Nanocubes, Nanobars and Nanobricks, Their Antimicrobial and Anticancer Properties

2021 ◽  
Vol 21 (10) ◽  
pp. 5337-5343
Author(s):  
Nilam Qureshi ◽  
Seungjae Lee ◽  
Ravindra Chaudhari ◽  
Pramod Mane ◽  
Jayant Pawar ◽  
...  
Keyword(s):  
Chemical Characterization ◽  
Growth Curves ◽  
Viable Cell ◽  
Inhibition Zone ◽  
Bacterial Cells ◽  
Hydrothermal Route ◽  
3 Dimensional ◽  
Anticancer Properties ◽  
Bacteria And Fungi ◽  
Micro Organisms

In our current endeavor, 3-dimensional (3D) tungsten oxide (WO3) nanostructures (nanocubes, nanobars and nanobricks) have been swiftly generated via hydrothermal route at 160 °C for 24 h. Physico-chemical characterization of the resultant powder revealed formation of WO3 nanostructures with predominantly faceted cube, brick and rectangular bar-like morphology. The present study was also aimed at exploring the antimicrobial and anticancer potential of WO3 nanostructures. Antimicrobial activity was tested against different micro-organisms viz., Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli and Aspergillus fumigatus. The antibacterial and antifungal activity was ascertained against these micro-organisms by measuring the diameter of inhibition zone in agar well diffusion test which revealed that the resultant WO3 nanostructures acted as excellent antibacterial agents against both bacteria and fungi but were more effective against the fungus, A. fumigatus. To examine the growth curves of bacterial cells, time kill assay was monitored for E. coli, against which significant antibacterial action of WO3 nanostructures was noted. The anti-cancer activity of WO3 nanostructures was found to be concentration-dependent against KB cell line by viable cell count method. In our pilot study, WO3 nanostructures suspension with concentration in the range of 10−1 to 10−5 mg/ml was found to kill KB cells effectively.

Respiratory and Circulatory Responses to Hypoxia in the Lobster Homarus Americanus

1975 ◽  
Vol 62 (3) ◽  
pp. 637-655 ◽  
Author(s):  
B. R. MCMAHON ◽  
J. L. WILKENS
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Homarus Americanus ◽  
Control Mechanisms ◽  
Blood Oxygen ◽  
Experimental Conditions ◽  
Oxygen Levels ◽  
Wide Range ◽  
Oxygen Tensions

Contrary to previous reports, oxygen consumption is maintained over a wide range of external oxygen tensions in the lobster Homarus americanus. In animals acclimated to the experimental conditions this response is mediated by increased branchial pumping, increased effectiveness of oxygen uptake by the gills and an increased contribution by the respiratory pigment to the oxygen delivered to the tissues. Circulatory blood oxygen levels are generally high in lobsters resting in well-aerated water. Mechanisms for detection of hypoxia and possible control mechanisms are discussed.

scholarly journals Aerated Irrigation of Different Irrigation Levels and Subsurface Dripper Depths Affects Fruit Yield, Quality and Water Use Efficiency of Greenhouse Tomato

2020 ◽  
Vol 12 (7) ◽  
pp. 2703
Author(s):  
Yan Zhu ◽  
Huanjie Cai ◽  
Libing Song ◽  
Xiaowen Wang ◽  
Zihui Shang ◽  
...  
Keyword(s):  
Growth Performance ◽  
Water Use ◽  
Soluble Sugar ◽  
Taste Quality ◽  
Fruit Yield ◽  
Soil Aeration ◽  
Acid Ratio ◽  
Use Efficiency ◽  
Aeration Conditions ◽  
Irrigation Levels

Aerated irrigation (AI) is a method to mitigate rhizosphere hypoxia caused by the wetting front from subsurface drip irrigation (SDI). This study evaluated the impacts of AI on soil aeration, plant growth performance, fruit yield (tomato), irrigation water use efficiency (IWUE), fruit nutrition (lycopene and Vitamin C (VC)) and taste (soluble sugar, organic acid and sugar–acid ratio) quality. A three-factorial experiment including AI and SDI at three irrigation levels (W0.6, W0.8 and W1.0, corresponding with crop-pan coefficients of 0.6, 0.8 and 1.0) and two dripper depths (D15 and D25, burial at 15 and 25 cm, respectively), totaling 12 treatments overall, was conducted in a greenhouse during the tomato-growing season (April–July) in 2016. The AI improved soil aeration conditions, with significantly increased soil oxygen concentration and air-filled porosity relative to SDI. Moreover, the AI improved crop growth performance, with increased root morphology (diameter, length density, surface area and volume density), delayed flowering time, prolonged flowering duration and increased shoot (leaf, stem and fruit) dry weight, and harvest index. Fruit yield per plant, fruit weight, IWUE, the contents of lycopene, VC and soluble sugar, and sugar–acid ratio significantly increased under AI treatments (P < 0.05). As the irrigation level increased, fruit yield, number, and weight increased (P < 0.05), but IWUE and fruit lycopene, soluble sugar, and organic acid content decreased (P < 0.05). The dripper depth had no significant impact on fruit yield, nutrition and taste quality. Principal component analysis revealed that the optimal three treatments in terms of fruit yield, IWUE, and nutrition and taste quality were the treatments W0.6D25AI, W1.0D25AI and W1.0D15AI. These results suggest that AI can improve tomato growth performance and increase fruit yield, nutrition and taste quality, and IWUE through enhancing soil aeration conditions.

scholarly journals Genome-Wide Transcriptional Profiling of the Escherichia coli Response to a Proline-Rich Antimicrobial Peptide

2004 ◽  
Vol 48 (9) ◽  
pp. 3260-3267 ◽  
Author(s):  
Linda Tomasinsig ◽  
Marco Scocchi ◽  
Romina Mettulio ◽  
Margherita Zanetti
Keyword(s):  
Escherichia Coli ◽  
Bacterial Resistance ◽  
Transcriptional Profiling ◽  
Transcriptional Response ◽  
Bacterial Cells ◽  
Experimental Conditions ◽  
Bacterial Membranes ◽  
Transcriptional Alterations ◽  
Proline Rich Peptide ◽  
Bacterial Genes

ABSTRACT Most antimicrobial peptides (AMPs) impair the viability of target bacteria by permeabilizing bacterial membranes. However, the proline-rich AMPs have been shown to kill susceptible organisms without causing significant membrane perturbation and may act by inhibiting the activity of bacterial targets. To gain initial insight into the events that follow interaction of a proline-rich peptide with bacterial cells, we used DNA macroarray technology to monitor transcriptional alterations of Escherichia coli in response to challenge with a subinhibitory concentration of the proline-rich Bac7(1-35). Substantial changes in the expression levels of 70 bacterial genes from various functional categories were detected. Among these, 26 genes showed decreased expression, while 44 genes, including genes that are potentially involved in bacterial resistance to antimicrobials, showed increased expression. The generation of a transcriptional response under the experimental conditions used is consistent with the ability of Bac7(1-35) to interact with bacterial components and affect biological processes in this organism.

scholarly journals Microbial flocculant produced by a novel Paenibacillus sp., strain A9, using food processing wastewater to replace fermentation medium and its application for the removal of Pb(II) from aqueous solution

2019 ◽  
Vol 37 (9-10) ◽  
pp. 683-697 ◽  
Author(s):  
Binhui Jiang ◽  
Lili Fu ◽  
Wan Cao ◽  
Bo Zhang ◽  
Fengda Li ◽  
...  
Keyword(s):  
Cell Surface ◽  
Fermentation Broth ◽  
Removal Rate ◽  
Production Costs ◽  
Infrared Spectrometry ◽  
Bacterial Cells ◽  
Experimental Conditions ◽  
Spectrometry Analysis ◽  
Paenibacillus Sp ◽  
Food Wastewater

Due to high production costs, the popularization and application of microbial flocculants in the field of water treatment have been limited. In this study, the capture of lead ions by the fermentation broth of a novel Paenibacillus sp. strain A9 and cultured with food wastewater was further investigated. The results revealed that the production of MBFA9 could be increased significantly by adding a small amount of carbon and nitrogen to food wastewater. Under the best experimental conditions (pH 8.5, culture temperature 30°C, 150 r/min), adding 1% (m/v) carbon and 0.1% (m/v) nitrogen to 1% (v/v) wastewater resulted in a yield of MBFA9 of 6.29 g/l. At a temperature of 30°C, pH of 5, contact time of 35 min, and FBA9 dosage of 5%, the removal rate and removal capacity of Pb(II) reached the highest values of 95.1% and 317 mg/g, respectively. Field emission scanning electron microscopy analysis indicated that bacterial cells, metabolite small molecule acids, and MBFA9 in FBA9 all contributed to the removal of Pb(II). Fourier-transform infrared spectrometry analysis indicated that functional groups such as –OH, –COOH, –CO, and –NH2 existed in MBFA9 and on the cell surface. Various mechanisms involved in Pb(II) removal can occur simultaneously, including cell surface adsorption, microcrystallization, and biological flocculation.

Topical antimicrobial testing of burn wound micro-organisms: Evaluation of a new technique

Burns ◽  
1990 ◽  
Vol 16 (1) ◽  
pp. 64-66 ◽  
Author(s):  
T.E. Taddonio ◽  
P.D. Thomson ◽  
D.J. Smith ◽  
J.K. Prasad
Keyword(s):  
New Technique ◽  
Burn Wound ◽  
A New Technique ◽  
Micro Organisms ◽  
Topical Antimicrobial

Leeuwenhoek Lecture: Soil metabolism

1955 ◽  
Vol 143 (911) ◽  
pp. 159-178 ◽  
Keyword(s):  
Dynamic Equilibrium ◽  
Soil Microbiology ◽  
Ion Concentration ◽  
Complex Biological System ◽  
Hydrogen Ion Concentration ◽  
Aeration Conditions ◽  
The Subject ◽  
Micro Organisms ◽  
Physical And Chemical ◽  
Soil Metabolism

It is a signal honour to be invited to give the Leeuwenhoek Lecture, and I would like to thank the authorities of the Royal Society for their invitation to me to give this lecture on the chemical aspects of soil microbiology. Leeuwenhoek clearly perceived from his pioneer work that a vast world of micro-organisms lies in the soil. The importance of its study, both in the purely scientific domain and in the practical fields of agriculture and medicine, is only now being realized. I will try in this lecture to give a short description of some recent studies of the chemical aspects of soil microbiology with a few observations on their practical implications. Some conception of the enormous population of micro-organisms in soil is provided by the fact that there may be as many as 5000 million bacteria per gram of soil. This corresponds to a weight of over 4 tons of bacterial substance per acre of soil. The numbers of bacteria fluctuate very greatly depending on availability of food supply, moisture, aeration conditions, temperature, hydrogen-ion concentration of the soil, and other factors. Protozoa may reach figures of the order of 1 million per gram of soil and algae may exceed a hundred thousand per gram. Actinomycetes and fungi, the exact numbers of which are difficult to estimate, may have a combined weight in the soil equal to that of the bacteria. Kluyver (1953) makes a comment in his recent Leeuwenhoek Lecture that the weight of microbial protoplasm on earth surpasses that of animal protoplasm by almost twenty times. It is obvious, therefore, that in dealing with the subject of soil metabolism we are dealing with the metabolism of vast numbers of living cells, greatly exceeding the number of cells found in animal life. The organisms of soil do not develop in an unrestricted chaotic manner. They are, on the other hand, greatly dependent on each other, sharing many factors in common. Soil may be considered to be a complex biological system in which hosts of organisms compete with each other often for a limited supply of nutritional material. They exercise profound effects on each others’ development and chemical activities, and they establish between themselves a dynamic equilibrium which continually changes with the changes in the physical and chemical environment of the soil.

Über die circadiane Variation der Stoffwechselgröße des isolierten Gewebes / Circadian Rhythm of Metabolie Rate in Isolated Tissue

1978 ◽  
Vol 33 (11-12) ◽  
pp. 955-961
Author(s):  
H. J. Schmidt
Keyword(s):  
Circadian Rhythm ◽  
Oxygen Uptake ◽  
Metabolic Rate ◽  
Circadian Variation ◽  
Experimental Conditions ◽  
Single Experiment ◽  
Experimental Time ◽  
Relative Maximum ◽  
Stabilisation Period ◽  
Locomotive Activity

The circadian variation of oxygen uptake of isolated mouse diaphragm has been measured by means of the direct Warburg-technique in two series with sets of each 8 successive experiments. Under our experimental conditions oxygen uptake in the isolated diaphragm remains constant for 5 hours at least. The 24-hour period could therefore be completed with 8 single measurements of each 10 - 20 isolated diaphragms started at 3 h intervals with a overlap in experimental time of 2 h hours between each single experiment. Similar to the results concerning the spontaneous locomotive activity of the mouse (ASCHOFF 1955) we found maximum values of metabolic rate during the night, minimum values during day time and a interpolated relative maximum of oxygen uptake between 600 -800 h. Oxygen uptake after the stabilisation period of approximately 1 h seems to be determined by the time of the death of the animal.

Basal Oxygen Uptake: A New Technique for an Old Test*

1986 ◽  
Vol 62 (5) ◽  
pp. 863-868 ◽  
Author(s):  
VICTORIA S. LIM ◽  
DONALD C. ZAVALA ◽  
MICHAEL J. FLANIGAN ◽  
RICHARD M. FREEMAN
Keyword(s):  
Oxygen Uptake ◽  
New Technique ◽  
A New Technique
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