Microbial assembly adapted to low-P soils in three subtropical forests by increasing the maximum rate of substrate conversion of acid phosphatases but not by decreasing the half-saturation constant

2022 ◽  
Vol 108 ◽  
pp. 103377
Author(s):  
Taiki Mori ◽  
Senhao Wang ◽  
Wei Zhang ◽  
Jiangming Mo
Keyword(s):  
Maximum Rate ◽  
Acid Phosphatases ◽  
Subtropical Forests ◽  
Half Saturation Constant ◽  
Substrate Conversion

Uptake of cytidine by isolated, perfused mouse liver

1982 ◽  
Vol 60 (2) ◽  
pp. 167-173 ◽  
Author(s):  
Norbert Kolassa ◽  
Alan R. P. Paterson
Keyword(s):  
Initial Phase ◽  
Maximum Rate ◽  
Mouse Liver ◽  
Nucleoside Transport ◽  
Transport Inhibitor ◽  
Half Saturation Constant ◽  
Inulin Space ◽  
Zero Values ◽  
Time Courses ◽  
Nucleoside Transport Inhibitor

Mouse livers were perfused at 22 °C with an oxygenated salts medium containing [5−3H]cytidine and [carboxyl-14C]inulin. The cellular uptake of cytidine was determined from the 3H content of liver samples less that present in the extracellular (inulin) space of the samples. Time courses of cytidine uptake were biphasic with initial phases which were approximately linear for 15 s and had time zero values that approximated the extracellular space. Rates of cytidine uptake derived from the initial phase of uptake evidently represented rates of membrane transport because (i) initial rates were saturable, and (ii) cytidine uptake was blocked by the nucleoside transport inhibitor, nitrobenzylthioinosine (NBMPR). Treatment of mice with the 5′-monophosphate of NBMPR (> 0.2 mg/kg, injected i.p.) 30–40 min prior to the perfusion also blocked cytidine entry into livers. An apparent half-saturation constant of about 10−3 M and a maximum rate of about 1 μmol∙g−1∙min−1 were estimated for the NBMPR-sensitive transport of cytidine into mouse liver cells.

scholarly journals Microbial grazers may aid in controlling infections caused by aquatic zoosporic fungi

2020 ◽  
Author(s):  
Hazel N. Farthing ◽  
Jiamei Jiang ◽  
Alexandra J. Henwood ◽  
Andy Fenton ◽  
Trent Garner ◽  
...  
Keyword(s):  
Maximum Rate ◽  
Batrachochytrium Dendrobatidis ◽  
Tetrahymena Pyriformis ◽  
Disease Dynamics ◽  
Free Living ◽  
Half Saturation Constant ◽  
Dispersal Stage ◽  
Zoosporic Fungi ◽  
Eukaryotic Microbes ◽  
Dynamics Simulations

AbstractFree-living eukaryotic microbes may reduce animal diseases. We evaluated the dynamics by which micrograzers (primarily protozoa) apply top-down control on the chytrid Batrachochytrium dendrobatidis (Bd) a devastating, panzootic pathogen of amphibians. Although micrograzers consumed zoospores (∼3 µm), the dispersal stage of chytrids, not all species grew monoxenically on zoospores. However, the ubiquitous ciliate Tetrahymena pyriformis, which likely co-occurs with Bd, grew at near its maximum rate (r = 1.7 d-1). A functional response (ingestion vs. prey abundance) for T. pyriformis, measured using spore-surrogates (microspheres) revealed maximum ingestion (Imax) of 1.63 × 103 zoospores d-1, with a half saturation constant (k) of 5.75 × 103 zoospores ml-1. Using these growth and grazing data we developed and assessed a population model that incorporated chytrid-host and micrograzer dynamics. Simulations using our data and realistic parameters obtained from the literature suggested that micrograzers could control Bd and potentially prevent chytridiomycosis (defined as 104 sporangia host-1). However, simulated inferior micrograzers (0.7 x Imax and 1.5 x k) did not prevent chytridiomycosis, although they ultimately reduced pathogen abundance to below levels resulting in disease. These findings indicate how micrograzer responses can be applied when modelling disease dynamics for Bd and other zoosporic fungi.

scholarly journals Microbial Grazers May Aid in Controlling Infections Caused by the Aquatic Zoosporic Fungus Batrachochytrium dendrobatidis

2021 ◽  
Vol 11 ◽  
Author(s):  
Hazel N. Farthing ◽  
Jiamei Jiang ◽  
Alexandra J. Henwood ◽  
Andy Fenton ◽  
Trent W. J. Garner ◽  
...  
Keyword(s):  
Population Model ◽  
Maximum Rate ◽  
Batrachochytrium Dendrobatidis ◽  
Tetrahymena Pyriformis ◽  
Disease Dynamics ◽  
Free Living ◽  
Half Saturation Constant ◽  
Dispersal Stage ◽  
Eukaryotic Microbes ◽  
Dynamics Simulations

Free-living eukaryotic microbes may reduce animal diseases. We evaluated the dynamics by which micrograzers (primarily protozoa) apply top-down control on the chytrid Batrachochytrium dendrobatidis (Bd) a devastating, panzootic pathogen of amphibians. Although micrograzers consumed zoospores (∼3 μm), the dispersal stage of chytrids, not all species grew monoxenically on zoospores. However, the ubiquitous ciliate Tetrahymena pyriformis, which likely co-occurs with Bd, grew at near its maximum rate (r = 1.7 d–1). A functional response (ingestion vs. prey abundance) for T. pyriformis, measured using spore-surrogates (microspheres) revealed maximum ingestion (Imax) of 1.63 × 103 zoospores d–1, with a half saturation constant (k) of 5.75 × 103 zoospores ml–1. Using these growth and grazing data we developed and assessed a population model that incorporated chytrid-host and micrograzer dynamics. Simulations using our data and realistic parameters obtained from the literature suggested that micrograzers could control Bd and potentially prevent chytridiomycosis (defined as 104 sporangia host–1). However, simulated inferior micrograzers (0.7 × Imax and 1.5 × k) did not prevent chytridiomycosis, although they ultimately reduced pathogen abundance to below levels resulting in disease. These findings indicate how micrograzer responses can be applied when modeling disease dynamics for Bd and other zoosporic fungi.

Neuronal and Extraneuronal Uptake of 3H-Norepinephrine in the Heart of the Active Bat: An Electron Microscopic Radioautographic Study

1973 ◽  
Vol 31 ◽  
pp. 522-523
Author(s):  
Martin Hagopian ◽  
Michael D. Gershon ◽  
Eladio A. Nunez
Keyword(s):  
Smooth Muscle ◽  
Monoamine Oxidase ◽  
Vascular Smooth Muscle ◽  
Cardiac Muscle ◽  
Maximum Rate ◽  
External Medium ◽  
Extraneuronal Uptake ◽  
Electron Microscopic ◽  
Cardiac Tissues ◽  
High Affinity

The ability of cardiac tissues to take up norepinephrine from an external medium is well known. Two mechanisms, called Uptake and Uptake respectively by Iversen have been differentiated. Uptake is a high affinity system associated with adrenergic neuronal elements. Uptake is a low affinity system, with a higher maximum rate than that of Uptake. Uptake has been associated with extraneuronal tissues such as cardiac muscle, fibroblasts or vascular smooth muscle. At low perfusion concentrations of norepinephrine most of the amine taken up by Uptake is metabolized. In order to study the localization of sites of norepinephrine storage following its uptake in the active bat heart, tritiated norepinephrine (2.5 mCi; 0.064 mg) was given intravenously to 2 bats. Monoamine oxidase had been inhibited with pheniprazine (10 mg/kg) one hour previously to decrease metabolism of norepinephrine.

Localization of acid phosphatases in root cap of rice plant

1991 ◽  
Vol 49 ◽  
pp. 224-225
Author(s):  
Y. R. Chen ◽  
Y. F. Huang ◽  
W. S. Chen
Keyword(s):  
Rice Plant ◽  
Developmental Stages ◽  
Uranyl Acetate ◽  
Root Cap ◽  
Plant Tissues ◽  
Acid Phosphatases ◽  
Root Tips ◽  
Buffer Solution ◽  
Cacodylate Buffer ◽  
Ethanol Series

Acid phosphatases are widely distributed in different tisssues of various plants. Studies on subcellular localization of acid phosphatases show they might be present in cell wall, plasma lemma, mitochondria, plastid, vacuole and nucleus. However, their localization in rice cell varies with developmental stages of cells and plant tissues. In present study, acid phosphatases occurring in root cap are examined.Sliced root tips of ten-day-old rice(Oryza sativa) seedlings were fixed in 0.1M cacodylate buffer containing 2.5% glutaraldehyde for 2h, washed overnight in same buffer solution, incubated in Gomori's solution at 37° C for 90min, post-fixed in OsO4, dehydrated in ethanol series and finally embeded in Spurr's resin. Sections were doubly stained with uranyl acetate and lead citrate, and observed under Hitachi H-600 at 75 KV.

The Demonstration of Human Prostatic Acid Phosphatase (Pap) With Phosphorylcholine

1976 ◽  
Vol 34 ◽  
pp. 88-89
Author(s):  
José A. Serrano ◽  
Hannah L. Wasserkrug ◽  
Anna A. Serrano ◽  
Arnold M. Seligman
Keyword(s):  
Acid Phosphatase ◽  
Prostate Gland ◽  
Prostatic Acid Phosphatase ◽  
Human Prostate ◽  
Rat Tissues ◽  
Specific Substrate ◽  
Acid Phosphatases ◽  
Lysosomal Acid ◽  
Cacodylate Buffer

As previously reported (1, 2) phosphorylcholine (PC) is a specific substrate for prostatatic acid phosphatase (PAP) as opposed to other acid phosphatases, e.g., lysosomal acid phosphatase. The specificity of PC for PAP is due to the pentavalent nitrogen in PC, a feature that renders PC resistant to hydrolysis by all other acid phosphatases. Detailed comparative cytochemical results in rat tissues are in press. This report deals with ultracytochemical results applying the method to normal and pathological human prostate gland.Fresh human prostate was obtained from 7 patients having transurethral resections or radical prostatectomies. The tissue was fixed in 3% glutaraldehyde- 0.1 M cacodylate buffer (pH 7.4) for 15 min, sectioned at 50 μm on a Sorvall TC-2 tissue sectioner, refixed for a total of 2 hr, and rinsed overnight in 0.1 M cacodylate buffer (pH 7.4)-7.5% sucrose.

The role of acid phosphatases in plant phosphorus metabolism

1994 ◽  
Vol 90 (4) ◽  
pp. 791-800 ◽  
Author(s):  
Stephen M. G. Duff ◽  
Gautam Sarath ◽  
William C. Plaxton
Keyword(s):  
Phosphorus Metabolism ◽  
Acid Phosphatases

Prothrombin Evaluation as Obtained by Kinetics Studies of Antigen-Antibody Reaction in a Laser Nephelometer

1984 ◽  
Vol 52 (01) ◽  
pp. 015-018 ◽  
Author(s):  
A Girolami ◽  
A Sticchi ◽  
R Melizzi ◽  
L Saggin ◽  
G Ruzza
Keyword(s):  
Liver Cirrhosis ◽  
Cirrhotic Patient ◽  
Maximum Rate ◽  
Serum Proteins ◽  
Clotting Factors ◽  
Kinetics Studies ◽  
Maximum Value ◽  
Time Required ◽  
Antigen Antibody ◽  
Kinetics Of

SummaryLaser nephelometry is a technique which allows the evaluation of the concentration of several serum proteins and clotting factors. By means of this technique it is also possible to study the kinetics of the reaction between antigen and antibody. We studied the kinetics of the reaction between prothrombin and an antiprothrombin antiserum using several prothrombins namely: Prothrombin Padua, prothrombin Molise, which are two congenital dysprothrombinemias, cirrhotic, coumarin or normal prothrombins. Different behaviors in the kinetics of the reactions were shown even when the concentration of prothrombins was about the same in all plasma tested. These differences were analyzed by means of a computer (Apple II 48 RAM) programmed to solve four unknown equations (Rodbard’s equation). From the data so obtained one can see that when voltages at the beginning and at the end of the reaction are in all cases about the same, a clear difference in the time required to reach half the maximum value of the voltage can still be demonstrated. This parameter, which is expressed in minutes, is longer in coumarin and prothrombin Molise than in controls. On the contrary it is shorter in prothrombin Padua and has about the same value of controls in the cirrhotic patient. Moreover the time at which the maximum rate is obtained is longer in coumarin and prothrombin Molise than in controls and shorter in liver cirrhosis and prothrombin Padua. In conclusion data obtained show that coumarin prothrombin behaves in a different way from cirrhotic prothrombin and also that there is a different behaviour between the two congenital dysprothrombinemias.

Modeling Trienzyme Biosensor at Internal Diffusion Limitation

2004 ◽  
Vol 9 (2) ◽  
pp. 139-144 ◽  
Author(s):  
J. Kulys
Keyword(s):  
Immobilized Enzymes ◽  
Internal Diffusion ◽  
Significant Response ◽  
Diffusion Limitation ◽  
Enzyme Reactions ◽  
Substrate Conversion ◽  
Apparent Stability ◽  
Biosensor Response

A model of biosensor containing three immobilized enzymes utilizing consecutive substrate conversion in the chain was developed. The modeling was performed at an internal diffusion limitation and a steadystate condition. The calculations showed that significant response of biosensors was produced if diffusion modules were larger than 1 for all enzyme reactions. Due to diffusion limitation the apparent stability of biosensor response increased many times in comparison to stability of the most labile enzyme of the chain.

SELECTED MORPHOMETRIC AND BIOLOGICAL CHARACTERISTICS OF IDE LEUCISCUS IDUS (LINNAEUS, 1758) IN THE LOWER IRTYSH

2017 ◽  
pp. 46-53
Author(s):  
Elizaveta L'vovna Liberman ◽  
Andrey Aleksandrovich Chemagin
Keyword(s):  
Maximum Rate ◽  
Linear Growth ◽  
Age Groups ◽  
Annual Growth ◽  
Recreational Fishing ◽  
Opisthorchis Felineus ◽  
Gonad Maturity ◽  
Study Results ◽  
Leuciscus Idus ◽  
Old Females

Ide Leuciscus idus (Linnaeus, 1758) belongs to Cyprinidae family and is used in commercial and recreational fishing. Ide is an intermediate host of Opisthorchis felineus . In the control catches (summer 2015, the Lower Irtysh, Uvatsky, Tobolsky and Vagaysky regions of Tyumenskaya Oblast’) there were observed species with lengths 11.9-38.1 cm, with a total weight 45-1085 g. Some species aged 9 years old and even older. The maximum rate of linear growth was registered in ide species younger than 3 years old, at this age annual growth made 5 cm. The annual growth of four-year-old females made 5.4 cm, males - 2.8 cm. Females aged 3+ exceeded males in body weight and length. Species at the age 1+…2+ years old added 204.6% in their mass; at the age 2+…3+ years old - 65.3%, at 3+…4+ years old - 29.4%. Gender and gonad maturity were determined in species older than 2+, but not in all species. Among females aged 2+…4+ there were found species with I and II stage of gonad maturity. Females aged 5+ were spawned-out species having VI-II stage of gonad maturity (48%); female species aged 6+ having IV stage of gonad maturity made 33.4%. Among males in the age groups of 2+ and 3+ there were registered species with I stage (38.5 and 20%, respectively) and II stage (61.5 and 80%, respectively) of maturation only. Fatness degree of studied species ranged from 0 to 5. Species aged 2+ had I stage (24% species); in the aged groups the proportion of such species decreased (5+ years old - 7.8%; 6+ years old - 12.1%; 8+ years old - 5.9%); species aged 2-7 had II stage of fatness; proportion of older species also decreased. Species with III and IV stage of fatness were found more often (III stage was observed in 100% of the fish species at the age of 1+). Proportion of species with V stage was minor, it increased with age. According to the analysis of the study results, nutritive base in the basin is found satisfactory for ide growth and development.

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