A Modification of Lerke Enzymic Test for Histamine Quantification

1994 ◽  
Vol 57 (11) ◽  
pp. 1019-1021 ◽  
Author(s):  
J. J. RODRIGUEZ-JEREZ ◽  
M. AUSILIA GRASSI ◽  
TIZIANA CIVERA
Keyword(s):  
Constant Temperature ◽  
Incubation Time ◽  
Reliable Method ◽  
Low Cost ◽  
Food Samples ◽  
Bacterial Strains ◽  
Optimum Wavelength ◽  
Short Incubation Time

A modification of Lerke enzymic method for histamine determination has been realized. We have observed a modification of the optimum wavelength depending on incubation time at constant temperature of 37°C. A wavelength of 580 nm is recommended, with a incubation time of 15 min. At these conditions the linearity was observed among 1 and 25 ppm (μg/g) of histamine. This technique is a reliable method of screening in food samples and bacterial strains, with low sample preparations requirements, a short incubation time and a low cost.

scholarly journals The Oleaginous Yeast Metschnikowia pulcherrima Displays Killer Activity against Avian-Derived Pathogenic Bacteria

Biology ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1227
Author(s):  
Robert H. Hicks ◽  
Mauro Moreno-Beltrán ◽  
Deborah Gore-Lloyd ◽  
Christopher J. Chuck ◽  
Daniel A. Henk
Keyword(s):  
Pathogenic Bacteria ◽  
Low Cost ◽  
Industrial Applications ◽  
Microbial Interactions ◽  
Bacterial Strains ◽  
Bacterial Killing ◽  
Killer Activity ◽  
Metschnikowia Pulcherrima ◽  
Livestock Health ◽  
Yeast Interactions

Metschnikowia pulcherrima is a non-conventional yeast with potential to be used in biotechnological processes, especially those involving low-cost feedstock exploitation and biocontrol applications. The combination of traits that supports these industrial applications in M. pulcherrima also makes it an attractive option to study in the context of livestock health. In this study, we examined the specific interactions between M. pulcherrima and multiple avian pathogenic bacteria. We tested individual bacteria–yeast interactions and bacterial combinations in both solid and liquid media and in variable nutrient environments. Across multiple isolates of M. pulcherrima, we observed different levels of antimicrobial activity, varying from supporting the growth of competing bacteria through suppression and bacterial killing, and we found that these responses varied depending on the bacterial strains and media. We identified multiple molecular routes, including proteins produced by M. pulcherrima strains, that acted to control these microbial interactions. Furthermore, protein screening revealed that M. pulcherrima strains were induced to produce proteins specifically when exposed to bacterial strains, suggesting that fine-tuned mechanisms allow M. pulcherrima to function as a potential lynchpin in a microbial community.

scholarly journals Cost-Effective Fabrication, Antibacterial Application and Cell Viability Studies of Modified Nonwoven Cotton Fabric

2021 ◽  
Author(s):  
Rahat Nawaz ◽  
Sayed Tayyab Raza Naqvi ◽  
Batool Fatima ◽  
Nazia Zulfiqar ◽  
Muhammad Umer Farooq ◽  
...  
Keyword(s):  
Cotton Fabric ◽  
Biomedical Applications ◽  
Active Sites ◽  
Food Packaging ◽  
Low Cost ◽  
Bacterial Species ◽  
Enterobacter Aerogenes ◽  
Cost Effective ◽  
Bacterial Strains ◽  
Toxicity Assay

Abstract Nonwoven cotton fabric has been fabricated and designed for antibacterial applications using low cost and ecofriendly precursors. The treatment of fabric with alkali leads to formation of active sites. The surfaces were dip coated with silver nanaoparticles and chitosan. The surface was chlorinated in next step to transform amide (N-H) groups in chitosan into N-halamine (N-Cl). The modified and unmodified surfaces of the nonwoven cotton fabric have been characterized by FTIR, SEM, and XRD. The active chlorine loading is measured with iodine/ sodium thiosulphate. The antimicrobial activity and cell toxicity assay were carried out with and without modifications of nonwoven cotton fabric. The antimicrobial efficacies of loaded fabric were evaluated against four bacterial species (Micrococcus lutes, Staphylococcus aurea, Enterobacter aerogenes, and E.coli). It was found that modified fabric exhibited superior efficiency against gram-positive and gram-negative bacterial strains as compared to their bulk counterparts upon exposure without destroying and affecting fabric nature. The overall process is economical for commercial purposes. The modified fabric can be used for antimicrobial, health, and food packaging industries, and in other biomedical applications.

Development of Rapid Colorimetric Assay for Detection of Gluconic Acid Using Iron(Ⅱ) and Indigo Carmine

2020 ◽  
Vol 42 (4) ◽  
pp. 525-525
Author(s):  
Yifeng Lan Yifeng Lan ◽  
Lixiang Zuo Lixiang Zuo ◽  
Yangyang Zhou Yangyang Zhou ◽  
Yanli Wei and Chuan Dong Yanli Wei and Chuan Dong
Keyword(s):  
Spectrophotometric Method ◽  
Gluconic Acid ◽  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Low Cost ◽  
Indigo Carmine ◽  
Colorimetric Method ◽  
Food Samples ◽  
Reducing Agent ◽  
Acid Complex

In this work, a simple and rapid spectrophotometric method, which is based on the fact that Iron(Ⅱ) -gluconic acid complex as a kind of reducing agent deterioration of indigo carmine dyes, was developed to detect gluconic acid in food. Under the optimal experimental condition, a linear range of 3.6 M to 900 M was obtained for gluconic acid with a limit of detection of 1.1 μM. The colorimetric method was rapid and robust with a low cost and can be applied to gluconic acid detection in food samples.

Immunoradiometric assay with use of magnetizable particles: measurement of thyrotropin in blood spots, to screen for neonatal hypothyroidism.

1986 ◽  
Vol 32 (10) ◽  
pp. 1966-1968 ◽  
Author(s):  
K V Waite ◽  
G F Maberly ◽  
G Ma ◽  
C J Eastman
Keyword(s):  
Incubation Time ◽  
Separation Procedure ◽  
Immunoradiometric Assay ◽  
Assay Sensitivity ◽  
Neonatal Hypothyroidism ◽  
Blood Spots ◽  
Standard Curve ◽  
Coefficients Of Variation ◽  
Specialized Equipment ◽  
Short Incubation Time

Abstract We adapted a commercial immunoradiometric assay (IRMA) to measure thyrotropin in filter-paper blood spots. Two 3-mm blood spots are used for each standard and sample. These are incubated for 2 h with radiolabeled antibody and for 30 min with magnetic antibody, followed by a 10-min separation procedure. Assay sensitivity is 6 milli-int. units/L. Coefficients of variation (precision profile of the standard curve) ranged from 4.3 to 9.6%. The coefficient of correlation (r) between thyrotropin concentrations in the blood spots and in serum was 0.93. Pre-elution of the blood spots is necessary for short incubation time. Short incubation time, little need for specialized equipment, the high precision and sensitivity characteristic of IRMA, and ease of collection, transport, and storage of the blood-spot samples make this assay suitable for neonatal hypothyroid screening.

Use of Iron Milk Medium for Enumeration of Clostridium perfringens

1982 ◽  
Vol 65 (5) ◽  
pp. 1129-1133 ◽  
Author(s):  
William D St John ◽  
Jack R Matches ◽  
Marleen M Wekell
Keyword(s):  
Clostridium Perfringens ◽  
Incubation Time ◽  
Incubation Temperature ◽  
Egg Yolk ◽  
Most Probable Number ◽  
Biochemical Tests ◽  
Probable Number ◽  
Large Numbers ◽  
Whole Milk ◽  
Short Incubation Time

Abstract A simple iron milk medium was used for isolation and enumeration of Clostridium perfringens from soil, sludge, and water samples. The whole milk contained only iron powder as a reducing agent; no other inhibitors were added. The iron milk most probable number (MPN) procedure was compared with 4 plating media: sulfite-polymyxin-sulfadiazine, Shahidi-Ferguson perfringens, tryptose-sulfite- cycloserine (both with and without egg yolk), and tryptone-sulfite-neomycin. The selectivity of the iron milk relies solely on the rapid growth of C. perfringens at 45°C and the stormy fermentation reaction within 18 h. Isolates were confirmed as C. perfringens by standard biochemical tests. The iron milk MPN procedure compared very well with the 4 plating media tested. Selectivity of incubation temperature, short incubation time, and ease of identification by the characteristic stormy fermentation make this method ideal for enumerating C. perfringens from large numbers of samples.

Does cassava wastewater with a short incubation time affect soil organic carbon, microbial community and enzymatic activities?

CATENA ◽  
2018 ◽  
Vol 163 ◽  
pp. 354-360 ◽  
Author(s):  
Adriano dos Santos Moura ◽  
Erika Valente de Medeiros ◽  
Jéssica Emanuella da Silva Oliveira ◽  
Rafaela Felix da Franca ◽  
Anderson Dantas Lira ◽  
...  
Keyword(s):  
Microbial Community ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Incubation Time ◽  
Enzymatic Activities ◽  
Cassava Wastewater ◽  
Short Incubation Time

The individual and combined influence of temperature, time, pH and COD concentration on the biodegradation activities of selected bacterial strains grown on raw Baker's yeast effluent

1994 ◽  
Vol 30 (12) ◽  
pp. 97-106
Author(s):  
M. Van Der Merwe ◽  
T.J. Britz
Keyword(s):  
Fatty Acid ◽  
Environmental Factors ◽  
Factorial Design ◽  
Incubation Time ◽  
Volatile Fatty Acid ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Bacterial Strains ◽  
Data Set ◽  
Intermediary Metabolites

Five bacterial strains (Chryseomonas luteola, Fusobacterium mortiferum, Enterobacter agglomerans,Klebsiella oxytoca and an unidentified Gram-negative rod) were grown on raw baker's yeast effluent to assess the influence of environmental factors on biodegradation processes. A 3×4×3 factorial design was used to determine the effects of time, pH and COD concentration, at four different temperatures. Total volatile fatty acid production was chosen as the most representative indicator of biodegradation. Results showed that the strains differed greatly in their ability to produce anaerobic digester intermediary metabolites, under defined environmental conditions. The study showed that the degradation of the complex compounds in baker's yeast effluent could be enhanced by changing environmental factors. The most positive responses were obtained at the higher COD concentrations (30 g l−1), the higher pH values (6.0), after 24 to 48h incubation time and at the higher temperatures (35°C). The most positive effect (+355.00) was found forChryseomonas luteola at a 48h incubation time, COD concentration of 30 g l−1, pH of 6.0 and temperature of 35°C. The volatile fatty acid yields obtained by the strains differ from the statistical indications, but provide a valuable reference of the actual concentrations obtained during the experimental study. The factorial design represented the effects of environmental changes, while the quantitative TVFA data set gave experimental data. This study showed that the manipulation of various environmental factors in biologically controlled systems, such as anaerobic digesters, could further enhance the biodegradation efficiency of the microbial population in the raw effluent.

Automated assay of oxygen radical absorbance capacity with the COBAS FARA II

1995 ◽  
Vol 41 (12) ◽  
pp. 1738-1744 ◽  
Author(s):  
G Cao ◽  
C P Verdon ◽  
A H Wu ◽  
H Wang ◽  
R L Prior
Keyword(s):  
Reliable Method ◽  
Peroxyl Radical ◽  
Biological Tissues ◽  
Food Samples ◽  
Oxygen Radical ◽  
Oxygen Radical Absorbance Capacity ◽  
Oxygen Species ◽  
Automated Assay ◽  
Trolox Equivalent ◽  
Clinical Conditions

Abstract Reactive oxygen species are of interest in biology and medicine because of evidence relating them to aging and disease processes. A relatively simple but sensitive and reliable method for quantifying the oxygen radical absorbance capacity (ORAC) of antioxidants in biological tissues has been automated for use with the COBAS FARA II centrifugal analyzer with a fluorescence-measuring attachment. In this assay, beta-phycoerythrin (beta-PE) is used as an indicator protein, 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) as a peroxyl radical generator, and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) as a calibrator for antioxidant activity. This assay is unique because the reaction goes to completion so that both inhibition time and inhibition degree are considered in quantifying ORAC (micromoles of Trolox equivalent per liter or per gram of tissue). This method can be used not only for serum but also other tissue and food samples and is suitable for application to a range of nutritional and clinical conditions.

Ultrasound-Assisted Ionic Liquid-Dispersive Liquid–Liquid of Curcumin in Food Samples Microextraction and Its Spectrophotometric Determination

2019 ◽  
Vol 102 (1) ◽  
pp. 217-221 ◽  
Author(s):  
Yunus Emre Unsal ◽  
Mustafa Tuzen ◽  
Mustafa Soylak
Keyword(s):  
Ionic Liquid ◽  
Method Development ◽  
Low Cost ◽  
Cost Effective ◽  
Enrichment Factors ◽  
Food Samples ◽  
Ultrasound Assisted ◽  
Dispersive Liquid Liquid Microextraction ◽  
Development Methods

Abstract Background: A rapid and new ultrasound-assisted ionic liquid-dispersive liquid–liquid microextraction method (UA-IL-DLLME) was presented for the determination of curcumin by spectrophotometry. Objective: To determine trace levels of curcumin in food samples by using green and low-cost method development. Methods: 1-Butyl-3-methylimidazolium hexafluorophosphate was used to extract curcumin from sample solutions with the aid of sonication. Optimum extraction efficiency was determined by examining extraction solvents, pH, centrifugation speed, time, sonication period, and temperature. The influences of diverse ions on the recovery of curcumin were examined. The concentration of curcumin in the final solution was measured by spectrophotometer at 425 nm. Results: The enrichment factor achieved was 167. The LOD and the RSD were 0.51 μg/L and 4.3%, respectively. The presented method was performed to detect curcumin in 20 food samples. Conclusions: The presented UA-IL-DLLME method is simple, low in cost, environmentally friendly, rapid, and sensitive and requires minimal use of toxic organic solvents. Highlights: A microextraction method was applied to increase sensitivity. Higher enrichment factors and lower detection limits were observed. The proposed technique is easy, cost-effective, accurate, and precise.

Nucleation of Tungsten on Titanium Nitride with Hydrogen Reduction of Tungsten Hexafluoride

1992 ◽  
Vol 282 ◽  
Author(s):  
D. Srinivas ◽  
R. Foster ◽  
S. Marcus ◽  
R. Arora ◽  
H. Rebenne
Keyword(s):  
Titanium Nitride ◽  
Nucleation Rate ◽  
Incubation Time ◽  
Seed Layer ◽  
Total Pressure ◽  
Hydrogen Reduction ◽  
Reduction Process ◽  
Tungsten Hexafluoride ◽  
Short Incubation Time ◽  
Competing Reactions

ABSTRACTIn this work, a hydrogen (H2) reduction process has been developed which gives tungsten (W) nucleation on titanium nitride (TiN) adhesion layers with a very short incubation time, eliminating the need for a silane (SiH4reduced seed layer. The nucleation was found to be strongly dependent on the following factors: temperature of the substrate, total pressure in chamber, and gas introduction sequence into the reactor. Theenhanced nucleation rate has been explained based on two competing reactions: dissociation of H2, and formation of titanium subfluorides on the TiN surface.

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