Physiological studies with the fungus Saprolegnia megasperma isolated from the freshwater nematode Neomesomermis flumenalis

1975 ◽  
Vol 53 (24) ◽  
pp. 3032-3040 ◽  
Author(s):  
Richard A. Nolan
Keyword(s):  
Glutamic Acid ◽  
Glucose Utilization ◽  
Methionine Sulfoxide ◽  
Optimum Concentration ◽  
Optimum Temperature ◽  
Ph Indicators ◽  
Test Conditions ◽  
Optimum Ph ◽  
First Time ◽  
Aquatic Phycomycete

The aquatic phycomycete Saprolegnia megasperma Coker is recorded for the first time from the freshwater nematode Neomesomermis flumenalis (Welch) Nickle. The optimum temperature for growth of the fungus is between 13 and 19 °C, and the optimum pH is between 5.2 and 5.7. The pH indicators tested were non-toxic to this isolate. The optimum concentration of phosphate was 15 mM. The optimum concentration of lactalbumin hydrolyzate under the conditions used was 4 g/litre. Glucose utilization occurred readily; 40% of the original level was utilized by day 3, and by day 4 the glucose level had dropped to 9.6% of the day 0 level. All of the detectable glucose in the medium had been utilized by day 5 under the test conditions. The utilization of ninhydrin-positive substances from media that contained lactalbumin hydrolyzate with and without glucose was determined. Under both conditions the following substances were taken up from the medium: glycerophosphoethanolamine, L-methionine sulfoxide, L-aspartic acid, L-threonine, L-serine, L-proline, L-glutamic acid, glycine, L-alanine, DL-cystathionine, L-methionine, L-isoleucine, L-leucine, L-tyrosine, L-phenylalanine, L-lysine, L-histidine, L-tryptophan, L-arginine, and L-valine. Ammonia and urea were produced in both media by the isolate. The polyamines, putrescine, cadaverine, spermidine, and spermine, were not detected as being released during autolysis.

scholarly journals A DNA Ligase from a Hyperthermophilic Archaeon with Unique Cofactor Specificity

2000 ◽  
Vol 182 (22) ◽  
pp. 6424-6433 ◽  
Author(s):  
Masaru Nakatani ◽  
Satoshi Ezaki ◽  
Haruyuki Atomi ◽  
Tadayuki Imanaka
Keyword(s):  
Biochemical Study ◽  
Protein Product ◽  
Optimum Concentration ◽  
Dna Ligase ◽  
Gene Encoding ◽  
Hyperthermophilic Archaeon ◽  
Dna Ligases ◽  
Cofactor Specificity ◽  
Thermophilic Archaeon ◽  
Optimum Ph

ABSTRACT A gene encoding DNA ligase (ligTk ) from a hyperthermophilic archaeon, Thermococcus kodakaraensisKOD1, has been cloned and sequenced, and its protein product has been characterized. ligTk consists of 1,686 bp, corresponding to a polypeptide of 562 amino acids with a predicted molecular mass of 64,079 Da. Sequence comparison with previously reported DNA ligases and the presence of conserved motifs suggested that Lig Tk was an ATP-dependent DNA ligase. Phylogenetic analysis indicated that Lig Tk was closely related to the ATP-dependent DNA ligase fromMethanobacterium thermoautotrophicum ΔH, a moderate thermophilic archaeon, along with putative DNA ligases fromEuryarchaeota and Crenarchaeota. We expressedligTk in Escherichia coli and purified the recombinant protein. Recombinant Lig Tk was monomeric, as is the case for other DNA ligases. The protein displayed DNA ligase activity in the presence of ATP and Mg2+. The optimum pH of Lig Tk was 8.0, the optimum concentration of Mg2+, which was indispensable for the enzyme activity, was 14 to 18 mM, and the optimum concentration of K+ was 10 to 30 mM. Lig Tk did not display single-stranded DNA ligase activity. At enzyme concentrations of 200 nM, we observed significant DNA ligase activity even at 100°C. Unexpectedly, Lig Tk displayed a relatively small, but significant, DNA ligase activity when NAD+ was added as the cofactor. Treatment of NAD+ with hexokinase did not affect this activity, excluding the possibility of contaminant ATP in the NAD+ solution. This unique cofactor specificity was also supported by the observation of adenylation of Lig Tk with NAD+. This is the first biochemical study of a DNA ligase from a hyperthermophilic archaeon.

Immobilization and Characterization of Tannase and its Haze-removing

2009 ◽  
Vol 15 (6) ◽  
pp. 545-552 ◽  
Author(s):  
Erzheng Su ◽  
Tao Xia ◽  
Liping Gao ◽  
Qianying Dai ◽  
Zhengzhu Zhang
Keyword(s):  
Kinetic Parameter ◽  
High Activity ◽  
Green Tea ◽  
Storage Stability ◽  
Residual Activity ◽  
Black Tea ◽  
Optimum Temperature ◽  
Oolong Tea ◽  
Optimum Ph

Tannase was effectively immobilized on alginate by the method of crosslinking-entrapment-crosslinking with a high activity recovery of 76.6%. The properties of immobilized tannase were investigated. Its optimum temperature was determined to be 35 ° C, decreasing 10 °C compared with that of free enzyme, whereas the optimum pH of 5.0 did not change. The thermal and pH stabilities of immobilized tannase increased to some degree. The kinetic parameter, Km, for immobilized tannase was estimated to be 11.6 × 10-4 mol/L. Fe2+ and Mn2+ could activate the activity of immobilized tannase. The immobilized tannase was also applied to treat the tea beverage to investigate its haze-removing effect. The content of non-estern catechins in green tea, black tea and oolong tea increased by 52.17%, 12.94% and 8.83%, respectively. The content of estern catechins in green tea, oolong tea and black tea decreased by 20.0%, 16.68% and 5.04%, respectively. The anti-sediment effect of green tea infusion treated with immobilized tannase was significantly increased. The storage stability and reusability of the immobilized tannase were improved greatly, with 72.5% activity retention after stored for 42 days and 86.9% residual activity after repeatedly used for 30 times.

scholarly journals Novel role of the ER/SR Ca2+ sensor STIM1 in the regulation of cardiac metabolism

2019 ◽  
Vol 316 (5) ◽  
pp. H1014-H1026 ◽  
Author(s):  
Helen E. Collins ◽  
Betty M. Pat ◽  
Luyun Zou ◽  
Silvio H. Litovsky ◽  
Adam R. Wende ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Fatty Acid ◽  
Pyruvate Dehydrogenase ◽  
Glucose Utilization ◽  
Cardiac Metabolism ◽  
Mitochondrial Morphology ◽  
Acid Uptake ◽  
Stromal Interaction Molecule 1 ◽  
First Time

The endoplasmic reticulum/sarcoplasmic reticulum Ca2+ sensor stromal interaction molecule 1 (STIM1), a key mediator of store-operated Ca2+ entry, is expressed in cardiomyocytes and has been implicated in regulating multiple cardiac processes, including hypertrophic signaling. Interestingly, cardiomyocyte-restricted deletion of STIM1 (crSTIM1-KO) results in age-dependent endoplasmic reticulum stress, altered mitochondrial morphology, and dilated cardiomyopathy in mice. Here, we tested the hypothesis that STIM1 deficiency may also impact cardiac metabolism. Hearts isolated from 20-wk-old crSTIM1-KO mice exhibited a significant reduction in both oxidative and nonoxidative glucose utilization. Consistent with the reduction in glucose utilization, expression of glucose transporter 4 and AMP-activated protein kinase phosphorylation were all reduced, whereas pyruvate dehydrogenase kinase 4 and pyruvate dehydrogenase phosphorylation were increased, in crSTIM1-KO hearts. Despite similar rates of fatty acid oxidation in control and crSTIM1-KO hearts ex vivo, crSTIM1-KO hearts contained increased lipid/triglyceride content as well as increased fatty acid-binding protein 4, fatty acid synthase, acyl-CoA thioesterase 1, hormone-sensitive lipase, and adipose triglyceride lipase expression compared with control hearts, suggestive of a possible imbalance between fatty acid uptake and oxidation. Insulin-mediated alterations in AKT phosphorylation were observed in crSTIM1-KO hearts, consistent with cardiac insulin resistance. Interestingly, we observed abnormal mitochondria and increased lipid accumulation in 12-wk crSTIM1-KO hearts, suggesting that these changes may initiate the subsequent metabolic dysfunction. These results demonstrate, for the first time, that cardiomyocyte STIM1 may play a key role in regulating cardiac metabolism. NEW & NOTEWORTHY Little is known of the physiological role of stromal interaction molecule 1 (STIM1) in the heart. Here, we demonstrate, for the first time, that hearts lacking cardiomyocyte STIM1 exhibit dysregulation of both cardiac glucose and lipid metabolism. Consequently, these results suggest a potentially novel role for STIM1 in regulating cardiac metabolism.

Answering the Questions of the Psychologist Assessing the Visually Handicapped Child

1975 ◽  
Vol 69 (8) ◽  
pp. 350-353
Author(s):  
John L. Morse
Keyword(s):  
Classroom Observation ◽  
Handicapped Child ◽  
Test Results ◽  
Visual Condition ◽  
Inappropriate Behaviors ◽  
Test Conditions ◽  
Visually Handicapped ◽  
First Time

The most common question asked by the psychologist who is faced for the first time with assessing a visually handicapped child are answered. The 15 questions include such areas as the required information concerning visual condition, background of the client, test conditions, the role of the parents, classroom observation, behaviors observed during testing, evaluation of test results, expectations of parents and teachers, and modification of a child's inappropriate behaviors.

scholarly journals Properties of a new fungal b-galactosidase with potential application in the dairy industry

1999 ◽  
Vol 30 (3) ◽  
pp. 265-271 ◽  
Author(s):  
Rubens Cruz ◽  
Vinícius D'Arcádia Cruz ◽  
Juliana Gisele Belote ◽  
Marcelo de Oliveira Khenayfes ◽  
Claudia Dorta ◽  
...  
Keyword(s):  
Hydrolytic Activity ◽  
Industrial Applications ◽  
Transferase Activity ◽  
Optimum Temperature ◽  
Milk Whey ◽  
Beneficial Effects ◽  
Optimum Ph ◽  
Semi Solid ◽  
Good Productivity ◽  
Hydrolysis Of

<FONT FACE="Symbol">b</font>-Galactosidase or <FONT FACE="Symbol">b</font>-D-galactoside-galactohydrolase (EC. 3.2.1.23) is an important enzyme industrially used for the hydrolysis of lactose from milk and milk whey for several applications. Lately, the importance of this enzyme was enhanced by its galactosyltransferase activity, which is responsible for the synthesis of transgalactosylated oligosaccharides (TOS) that act as functional foods, with several beneficial effects on consumers. Penicillium simplicissimum, a strain isolated from soil, when grown in semi-solid medium showed good productivity of <FONT FACE="Symbol">b</font>-galactosidase with galactosyltransferase activity. The optimum pH for hydrolysis was in the 4.04.6 range and the optimum pH for galactosyltransferase activity was in the 6.07.0 range. The optimum temperature for hydrolysis and transferase activity was 55-60°C and 50°C, respectively, and the enzyme showed high thermostability for the hydrolytic activity. The enzyme showed a potential for several industrial applications such as removal of 67% of the lactose from milk and 84% of the lactose from milk whey when incubated at their original pH (4.5 and 6.34, respectively) under optimum temperature conditions. When incubated with a 40% lactose solution in 150 mM McIlvaine buffer, pH 4.5, at 55°C the enzyme converted 86.5% of the lactose to its component monosaccharides. When incubated with a 60% lactose solution in the same buffer but at pH 6.5 and 50°C, the enzyme can synthetize up to 30.5% TOS, with 39.5% lactose and 30% monosaccharides remaining in the preparation.

scholarly journals Characterization of Biosynthetic Enzymes for Ectoine as a Compatible Solute in a Moderately Halophilic Eubacterium, Halomonas elongata

1999 ◽  
Vol 181 (1) ◽  
pp. 91-99 ◽  
Author(s):  
Hisayo Ono ◽  
Kazuhisa Sawada ◽  
Nonpanga Khunajakr ◽  
Tao Tao ◽  
Mihoko Yamamoto ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Apparent Molecular Mass ◽  
Optimum Temperature ◽  
Sds Page ◽  
Halomonas Elongata ◽  
Optimum Ph

ABSTRACT 1,4,5,6-Tetrahydro-2-methyl-4-pyrimidinecarboxylic acid (ectoine) is an excellent osmoprotectant. The biosynthetic pathway of ectoine from aspartic β-semialdehyde (ASA), in Halomonas elongata, was elucidated by purification and characterization of each enzyme involved. 2,4-Diaminobutyrate (DABA) aminotransferase catalyzed reversively the first step of the pathway, conversion of ASA to DABA by transamination with l-glutamate. This enzyme required pyridoxal 5′-phosphate and potassium ions for its activity and stability. The gel filtration estimated an apparent molecular mass of 260 kDa, whereas molecular mass measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was 44 kDa. This enzyme exhibited an optimum pH of 8.6 and an optimum temperature of 25°C and had Km s of 9.1 mM forl-glutamate and 4.5 mM for dl-ASA. DABA acetyltransferase catalyzed acetylation of DABA to γ-N-acetyl-α,γ-diaminobutyric acid (ADABA) with acetyl coenzyme A and exhibited an optimum pH of 8.2 and an optimum temperature of 20°C in the presence of 0.4 M NaCl. The molecular mass was 45 kDa by gel filtration. Ectoine synthase catalyzed circularization of ADABA to ectoine and exhibited an optimum pH of 8.5 to 9.0 and an optimum temperature of 15°C in the presence of 0.5 M NaCl. This enzyme had an apparent molecular mass of 19 kDa by SDS-PAGE and a Km of 8.4 mM in the presence of 0.77 M NaCl. DABA acetyltransferase and ectoine synthase were stabilized in the presence of NaCl (>2 M) and DABA (100 mM) at temperatures below 30°C.

scholarly journals Immobilization of Isolated Lipase From Moldy Copra(Aspergillus Oryzae)

2011 ◽  
Vol 8 (2) ◽  
pp. 896-902
Author(s):  
Seniwati Dali ◽  
A. B. D. Rauf Patong ◽  
M. Noor Jalaluddin ◽  
Pirman ◽  
Baharuddin Hamzah
Keyword(s):  
Thermal Stability ◽  
Aspergillus Oryzae ◽  
Immobilized Lipase ◽  
Optimum Temperature ◽  
Adsorption Method ◽  
Ph Optimum ◽  
Optimum Ph ◽  
Recovery Technique ◽  
Free Lipase

Enzyme immobilization is a recovery technique that has been studied in several years, using support as a media to help enzyme dissolutions to the reaction substrate. Immobilization method used in this study was adsorption method, using specific lipase fromAspergillus oryzae. Lipase was partially purified from the culture supernatant ofAspergillus oryzae. Enzyme was immobilized by adsorbed on silica gel. Studies on free and immobilized lipase systems for determination of optimum pH, optimum temperature, thermal stability and reusability were carried out. The results showed that free lipase had optimum pH 8,2 and optimum temperature 35 °C while the immobilized lipase had optimum 8,2 and optimum temperature 45 °C. The thermal stability of the immobilized lipase, relative to that of the free lipase, was markedly increased. The immobilized lipase can be reused for at least six times.

Title: Bacteriophage Φ6 (Phi6) as a Surrogate for Enveloped Viral pathogens in Standard and Long-lasting Virucidal Efficacy Tests

2021 ◽  
Author(s):  
Jaime B. Hutchison ◽  
Chris Plummer ◽  
Gareth Garner ◽  
Amit Sehgal ◽  
Laura B. Purevdorj-Gage ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Quaternary Ammonium ◽  
Viral Pathogens ◽  
Enveloped Viruses ◽  
Surface Stability ◽  
Test Conditions ◽  
The Uk ◽  
First Time ◽  
Ammonium Compounds ◽  
Virucidal Efficacy

Abstract Development of novel antimicrobials capable of providing long-lasting disinfection on surfaces requires the implementation of new standardized methods to support claims recognized by regulatory authorities. Surrogates for viral pathogens are often desired in order for BSL-2 labs to conduct these new efficacy tests safely and efficiently, however, the knowledge of surrogate suitability for these tests is limited. Here, for the first time, we determine the resistance profile of the bacteriophage Phi6 to quaternary ammonium compounds (QACs) in a variety of test conditions. Additionally, we show that Phi6 can be used to demonstrate the long-lasting virucidal efficacy of a novel antimicrobial, Actizone™ F5, and that the Phi6 is more resistant to QACs following the UK standard long-lasting disinfection test BSI PAS2424:2014 than Vaccinia virus, which is the marker strain for claims of activity against enveloped viruses in Europe. Surface stability as well as benefits and limitations of Phi6 use relative to other enveloped viruses for antimicrobial testing is also discussed.

scholarly journals Preparation of Cross-Linked Enzyme Aggregates (CLEAs) of an Inulosucrase Mutant for the Enzymatic Synthesis of Inulin-Type Fructooligosaccharides

Catalysts ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 641 ◽  
Author(s):  
Thanapon Charoenwongpaiboon ◽  
Rath Pichyangkura ◽  
Robert A. Field ◽  
Manchumas Hengsakul Prousoontorn
Keyword(s):  
Enzymatic Synthesis ◽  
Biochemical Characterization ◽  
Lactobacillus Reuteri ◽  
Soluble Enzyme ◽  
Optimum Temperature ◽  
Optimum Conditions ◽  
Product Specificity ◽  
Product Characterization ◽  
Optimum Ph ◽  
Probiotic Activity

Fructooligosaccharides are well-known carbohydrate molecules that exhibit good probiotic activity and are widely used as sweeteners. Inulin-type fructooligosaccharides (IFOs) can be synthesized from sucrose using inulosucrase. In this study, cross-linked enzyme aggregates (CLEAs) of Lactobacillus reuteri 121 inulosucrase (R483A-LrInu) were prepared and used as a biocatalyst for IFOs production. Under optimum conditions, R483A-LrInu CLEAs retained 42% of original inulosucrase activity. Biochemical characterization demonstrated that the optimum pH of inulosucrase changed from 5 to 4 after immobilization, while the optimum temperature was unchanged. Furthermore, the pH stability and thermostability of the R483A-LrInu CLEAs was significantly improved. IFOs product characterization indicated that the product specificity of the enzyme was impacted by CLEA generation, producing a narrower range of IFOs than the soluble enzyme. In addition, the R483A-LrInu CLEAs showed operational stability in the batch synthesis of IFOs.

scholarly journals Xanthine Oxidase of the Clothes Moth, Tineola Bisselliella, and Some Other Insects

1955 ◽  
Vol 8 (3) ◽  
pp. 369 ◽  
Author(s):  
H Irzykiewicz
Keyword(s):  
Methylene Blue ◽  
Uric Acid ◽  
Toxic Effect ◽  
Xanthine Oxidase ◽  
Oxidase Activity ◽  
Acid Production ◽  
Fat Body ◽  
Optimum Concentration ◽  
Optimum Ph ◽  
Wet Weight

Xanthine oxidase activity in Tineola larvae averages 200� /!moles of uric acid per g whole larva (wet weight) per hr and in Tenebrio, Lucilia, Anthrenocerus, Ephestia, and Anthrenus larvae activity ranges between 13�4 and 1�3. The optimum pH for Tineola xanthine oxidase lies between pH 7�7 and 8� 0, and the optimum concentration of xanthine is at or below 1�3 X 10-3M. Methylene blue in concentrations up to 5�3 X 1O-3M has no toxic effect on this enzyme, and the lower concentrations of methylene blue have a limiting effect. Cyanide and 6-pteridyl aldehyde inhibit Tineola xanthine oxidase. The insect xanthine oxidases are demonstrated to be dehydrogenases. DPN, and pyruvate and DPN together, stimulate uric acid production by Tineola xanthine oxidase in the absence of methylene blue. In Tenebrio larvae there is a higher concentration of xanthine oxidase in the midgut and fat-body than in the remaining tissues.

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