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1.  Public and health professionals’ misconceptions about the dynamics of body weight gain/loss 
System dynamics review  2014;30(1-2):58-74.
Human body energy storage operates as a stock-and-flow system with inflow (food intake) and outflow (energy expenditure). In spite of the ubiquity of stock-and-flow structures, evidence suggests that human beings fail to understand stock accumulation and rates of change, a difficulty called the stock–flow failure. This study examines the influence of health care training and cultural background in overcoming stock–flow failure. A standardized protocol assessed lay people’s and health care professionals’ ability to apply stock-and-flow reasoning to infer the dynamics of weight gain/loss during the holiday season (621 subjects from seven countries). Our results indicate that both types of subjects exhibited systematic errors indicative of use of erroneous heuristics. Stock–flow failure was found across cultures and was not improved by professional health training. The problem of stock–flow failure as a transcultural global issue with education and policy implications is discussed.
PMCID: PMC4300993  PMID: 25620843
2.  Direct Determination of Glycidyl Esters of Fatty Acids in Vegetable Oils by LC–MS 
An LC–MS method using a single quadrupole mass spectrometer was developed for direct analysis of glycidyl esters of fatty acids in vegetable oils. Without any sample clean-up, this method provided acceptable recovery of seven glycidyl esters, comparable results to a previously-published method utilizing two solid-phase extraction steps, and consistent detection parameters after greater than 200 injections without any cleaning operations performed. This method could readily be implemented as a screening assay for glycidyl esters in most oil laboratories.
PMCID: PMC3143323  PMID: 21909156
Monochloropropanediol; 3-MCPD; MCPD; Glycidol; Glycidyl esters; LC–MS; Vegetable oil
3.  Direct Determination of MCPD Fatty Acid Esters and Glycidyl Fatty Acid Esters in Vegetable Oils by LC–TOFMS 
Analysis of MCPD esters and glycidyl esters in vegetable oils using the indirect method proposed by the DGF gave inconsistent results when salting out conditions were varied. Subsequent investigation showed that the method was destroying and reforming MCPD during the analysis. An LC time of flight MS method was developed for direct analysis of both MCPD esters and glycidyl esters in vegetable oils. The results of the LC–TOFMS method were compared with the DGF method. The DGF method consistently gave results that were greater than the LC–TOFMS method. The levels of MCPD esters and glycidyl esters found in a variety of vegetable oils are reported. MCPD monoesters were not found in any oil samples. MCPD diesters were found only in samples containing palm oil, and were not present in all palm oil samples. Glycidyl esters were found in a wide variety of oils. Some processing conditions that influence the concentration of MCPD esters and glycidyl esters are discussed.
PMCID: PMC3022155  PMID: 21350591
Monochloropropanediol; MCPD; Glycidol; Glycidyl esters; LC–TOFMS; Vegetable oil
4.  Role of blastospores in protecting Aspergillus parasiticus NRRL 3240 from high levels of aflatoxins. 
The role of blastospores in the protection of Aspergillus parasiticus from high levels of aflatoxins was studied. The strain protects itself from aflatoxicity by forming thick-walled blastospores. The formation of blastospores was not observed under conditions of reduced aflatoxin formation, e.g., under zinc and asparagine deficiencies. The germination of blastospores coincided with an increase in the specific activity of glutamate dehydrogenase (NADP) and a simultaneous decrease in the specific aflatoxin production.
PMCID: PMC242061  PMID: 7138001
5.  Inhibition of aflatoxin biosynthesis by tolnaftate. 
Tolnaftate [2-napthyl-N-methyl-N-(m-tolyl)thionocarbamate], an antifungal drug, is widely used to control superficial fungal infections in humans and other animals. In this study the effect of tolnaftate on aflatoxin biosynthesis by Aspergillus parasiticus NRRL 3240 was investigated. Tolnaftate changed the morphology of A. parasiticus to yeastlike forms and inhibited aflatoxin formation. The formation of aflatoxin G was blocked considerably, indicating a metabolic block in the conversion of aflatoxin B to aflatoxin G. The incorporation of [1-14C]acetate into aflatoxin was significantly inhibited at a concentration of 1 mM tolnaftate. The presence of zinc in the resuspension buffer resulted in reversal of the tolnaftate-induced inhibition of aflatoxin G1 biosynthesis.
PMCID: PMC291213  PMID: 697362
6.  Tryptophan Uptake By Mycobacterium tuberculosis H37Rv: Effect of Rifampin and Ethambutol 
Uptake of radioactive tryptophan by Mycobacterium tuberculosis H37Rv grown in vitro and in vivo was investigated. Km values indicated low affinity, and sodium azide inhibited uptake. Rifampin at the minimal inhibitory concentration had no effect, whereas ethambutol inhibited uptake only in the bacilli grown under in vitro conditions. The significance of these results is discussed.
PMCID: PMC352323  PMID: 96733
7.  Biosynthesis of aflatoxins. 
Bacteriological Reviews  1977;41(4):822-855.
PMCID: PMC414029  PMID: 23090
8.  Effect of zinc on adenine nucleotide pools in relation to aflatoxin biosynthesis in Aspergillus parasiticus. 
The adenylic acid systems of Aspergillus parasiticus were studied in zinc-replete and zinc-deficient media. The adenosine 5'-triphosphate levels of the fungus were high during exponential phase and low during stationary phase in zinc-replete cultures. On the other hand, the levels of adenosine 5'-diphosphate and adenosine 5'-monophosphate were low during exponential phase of growth and high during stationary phase. The adenosine 5'-triphosphate levels during exponential phase may indicate higher primary metabolic activity of the fungus. On the other hand, high adenosine 5'-monophosphate levels during stationary phase may inhibit lipid formation and may enhance aflatoxin levels. The inorganic phosphorus content was low in a zinc-replete medium throughout the growth period, thereby favoring aflatoxin biosynthesis. The energy charge during the exponential phase was high but low during the stationary phase. In general the energy charge values were lower because of high adenosine 5'-monophosphate content.
PMCID: PMC170456  PMID: 1008554
9.  Inhibition of aflatoxin formation by 2-mercaptoethanol. 
2-Mercaptoethanol inhibits growth of Aspergillus parasiticus NRRL 3240 and aflatoxin formation by the fungus. When added to the resuspended medium, 2-mercaptoethanol inhibited [1-14C]acetate incorporation into both aflatoxins and neutral lipids, thereby showing that it acts at an early stage of aflatoxin biosynthesis. The inhibition is probably due to its chelating action on zinc, which is essential for aflatoxin production. It is proposed that any chelating agent that selectively binds to zinc will inhibit aflatoxin formation.
PMCID: PMC170064  PMID: 984814
10.  Production of Aflatoxin on Soybeans 
Applied Microbiology  1975;29(6):834-836.
Probable factors influencing resistance to aflatoxin synthesis in soybeans have been investigated by using cultures of Aspergillus parasiticus NRRL 3240. Soybeans contain a small amount of zinc (0.01 μg/g) bound to phytic acid. Autoclaving soybeans at 15 pounds (6803.88 g) for 15 min increases the aflatoxin production, probably by making zinc available. Addition of zinc to both autoclaved and nonautoclaved soybeans promotes aflatoxin production. However, addition of varying levels of phytic acid at a constant concentration of zinc depresses aflatoxin synthesis with an increase in the added phytic acid. In a synthetic medium known to give good yields of aflatoxin, the addition of phytic acid (10 mM) decreases aflatoxin synthesis.
PMCID: PMC187088  PMID: 1171654
11.  Production of Aflatoxin M in a Liquid Medium 
Applied Microbiology  1975;29(6):850-851.
Aspergillus flavus NRRL 3251 grown on modified yeast extract-sucrose medium produced 1 mg of aflatoxin M1 per 100 ml of medium.
PMCID: PMC187091  PMID: 808169
12.  High Aflatoxin Production on a Chemically Defined Medium 1 
Applied Microbiology  1971;22(3):393-396.
Aspergillus parasiticus ATCC 15517 produced 28 to 30 mg of aflatoxin per 100 ml of a medium containing sucrose, asparagine, and salts in stationary and shaken cultures. In the absence of asparagine in the medium, the toxin yields fell drastically, and the thin-layer chromatograms of the chloroform extracts of the cultures indicated the total absence of aflatoxin G1 and the presence of new intense blue and green fluorescent bands having RF values lower than aflatoxins. Initial pH was critical and had to be around 4.5 for good growth and high toxin production on this medium. Optimum concentrations of KH2PO4 and MgSO4·7H2O in the medium were much lower than those normally used in fungal growth media.
PMCID: PMC376320  PMID: 5119206

Results 1-12 (12)