ABSTRACT
Nondestructive assay procedures for determining microbial lipolytic and proteolytic activity on marine substrates were developed and tested with 287 isolates of bacteria, filamentous fungi, and yeasts. A definite substrate specificity was noted when the enzymatic activities on marine and nonmarine substrates was compared. Of 170 lipolytic isolates, 14 were only active on menhaden oil, 11 could hydrolyze menhaden oil and Tween 80 and/or tributyrin, and 145 isolates could only hydrolyze one or both of the nonmarine lipids. Of the 198 proteolytic isolates, 10 were specific for codfish extract, 152 were active against the marine substrate plus casein and/or gelatin, and 36 were specific for nonmarine substrates.
Subject(s)
Bacteria/metabolism , Food Microbiology , Fungi/metabolism , Lipid Metabolism , Proteins/metabolism , Animals , Bacteria/enzymology , Caseins/metabolism , Dietary Proteins , Fishes , Fungi/enzymology , Gelatin/metabolism , Lipase/biosynthesis , Oils , Peptide Hydrolases/biosynthesis , Polysorbates/metabolism , Species Specificity , Tissue Extracts , Triglycerides/metabolism , Yeasts/enzymology , Yeasts/metabolismABSTRACT
Thirty-nine microorganisms representing 11 species of bacteria, one yeast, and three filamentous fungi were isolated and identified from four fermented fish sauces: nampla, patis, koami, and ounago.
ABSTRACT
Nineteen plants belonging to 11 species of the cruciferae were studied to determine the effects of aflatoxin B(1) on seed germination and seedling development. Germination was not inhibited in any test organism at a concentration of 100 mug of aflatoxin per ml of agar substrate. Inhibition of elongation of the hypocotyls and roots in the species studied varied from 29 to 93% and from 22 to 91% in the respective tissues. Lepidium sativum was the most susceptible plant studied and exhibited the maximal inhibitory response noted above at concentrations of 8 mug of aflatoxin per ml. The ultrastructure of Lepidium root cells treated with crystalline aflatoxin B(1) exhibited morphological changes characteristic of those found in aflatoxin-treated animal cells. In addition to changes in the cytoplasmic organelles, numerous ring-shaped nucleoli with prominent nucleolar caps were produced. The effect of aflatoxin on plant cells is compared with similar effects induced by actinomycin D. Seed germination and seedling development is discussed in relation to the effects of both compounds on deoxyribonucleic acid-dependent ribonucleic acid biosynthesis.
Subject(s)
Aflatoxins/pharmacology , Plants/drug effects , Cell Nucleolus/drug effects , Dactinomycin/pharmacology , Drug Resistance , Microscopy, Electron , Organoids/drug effects , Plant Cells , Plant Development , Plants/metabolism , RNA/biosynthesis , Seeds/drug effects , Seeds/growth & developmentABSTRACT
The relative susceptibility of 30 cultivars of lettuce to inhibition by aflatoxin was studied. Seed germination was not inhibited by concentrations as high as 1,000 mug/ml in cultivar Imperial 44 or by 100 mug/ml in the remaining cultivars. Hypocotyl elongation was inhibited by 46 to 68% at a concentration of 100 mug of aflatoxin per ml. Seedlings exposed to aflatoxin did not become chlorotic. The similarity between the morphological reaction of plants to coumarin and aflatoxin suggests a common mode of action, but further studies of the physiological basis for the inhibitory reactions induced by these compounds will be necessary before such conclusions will be valid.
Subject(s)
Aflatoxins/pharmacology , Plants, Edible/drug effects , Seeds/growth & development , Aflatoxins/biosynthesis , Agar , Aspergillus/metabolism , Chlorophyll/biosynthesis , Coumarins/pharmacology , Plants, Edible/growth & development , Plants, Edible/metabolism , Seeds/drug effects , VegetablesABSTRACT
A triple fixation method using a sequential application of 15 or 30% formaldehyde, 6% glutaraldehyde, and 1% osmium tetroxide resulted in excellent fixation of mature spores of Clostridium botulinum.
