The relationship of Aspergillus flavus and Aspergillus parasiticus with reference to production of aflatoxins and cyclopiazonic acid

1984 ◽  
Vol 87 (1-2) ◽  
pp. 13-15 ◽  
Author(s):  
Joe W. Dorner ◽  
Richard J. Cole ◽  
Urban L. Diener
Keyword(s):  
Aspergillus Flavus ◽  
Aspergillus Parasiticus ◽  
Cyclopiazonic Acid ◽  
Relationship Of ◽  
The Relationship

scholarly journals The relationship between contractile force and intracellular [Ca2+] in intact rat cardiac trabeculae.

1995 ◽  
Vol 105 (1) ◽  
pp. 1-19 ◽  
Author(s):  
P H Backx ◽  
W D Gao ◽  
M D Azan-Backx ◽  
E Marban
Keyword(s):  
Steady State ◽  
Cyclopiazonic Acid ◽  
Hill Coefficient ◽  
Atpase Inhibitor ◽  
Relaxation Phase ◽  
Contractile System ◽  
To Come ◽  
State Force ◽  
Relationship Of ◽  
The Relationship

The control of force by [Ca2+] was investigated in rat cardiac trabeculae loaded with fura-2 salt. At sarcomere lengths of 2.1-2.3 microns, the steady state force-[Ca2+]i relationship during tetanization in the presence of ryanodine was half maximally activated at a [Ca2+]i of 0.65 +/- 0.19 microM with a Hill coefficient of 5.2 +/- 1.2 (mean +/- SD, n = 9), and the maximal stress produced at saturating [Ca2+]i equalled 121 +/- 35 mN/mm2 (n = 9). The dependence of steady state force on [Ca2+]i was identical in muscles tetanized in the presence of the Ca(2+)-ATPase inhibitor cyclopiazonic acid (CPA). The force-[Ca2+]i relationship during the relaxation of twitches in the presence of CPA coincided exactly to that measured at steady state during tetani, suggesting that CPA slows the decay rate of [Ca2+]i sufficiently to allow the force to come into a steady state with the [Ca2+]i. In contrast, the relationship of force to [Ca2+]i during the relaxation phase of control twitches was shifted leftward relative to the steady state relationship, establishing that relaxation is limited by the contractile system itself, not by Ca2+ removal from the cytosol. Under control conditions the force-[Ca2+]i relationship, quantified at the time of peak twitch force (i.e., dF/dt = 0), coincided fairly well with steady state measurements in some trabeculae (i.e., three of seven). However, the force-[Ca2+]i relationship at peak force did not correspond to the steady state measurements after the application of 5 mM 2,3-butanedione monoxime (BDM) (to accelerate cross-bridge kinetics) or 100 microM CPA (to slow the relaxation of the [Ca2+]i transient). Therefore, we conclude that the relationship of force to [Ca2+]i during physiological twitch contractions cannot be used to predict the steady state relationship.

Relationship between soil densities ofAspergillusspecies and colonization of wounded peanut seeds

2006 ◽  
Vol 52 (10) ◽  
pp. 951-960 ◽  
Author(s):  
Bruce W Horn
Keyword(s):  
Aspergillus Flavus ◽  
Aspergillus Parasiticus ◽  
Fungal Species ◽  
Aspergillus Species ◽  
Soil Density ◽  
Peanut Seed ◽  
Wound Site ◽  
Seed Colonization ◽  
The Relationship ◽  
Fungal Competition

Soil is a reservoir for Aspergillus flavus and A. parasiticus, fungi that commonly colonize peanut seeds and produce carcinogenic aflatoxins. Densities of these fungi in soil vary greatly among fields and may influence the severity of peanut infection. This study examined the relationship between soil density of Aspergillus species and the incidence of peanut seed colonization under laboratory conditions. Viable peanut seeds were wounded and inoculated with 20 soils differing in composition and density of Aspergillus species and were then incubated for 14 days at 37 °C (seed water activity = 0.92). The effect of soil density of individual section Flavi species (A. flavus strains L and S, A. parasiticus, A. caelatus, and A. tamarii), section Nigri, and A. terreus on the incidence of seed colonization was best expressed as a function of exponential rise to maximum. Exponential curves often rose to maximum percentages of seed colonization by section Flavi species that were well below 100% despite high species densities in some soils. Competition primarily among section Flavi species may explain the reduced incidences of seed colonization. An average of two or fewer propagules of each Aspergillus species in the soil at the wound site was required for colonization of 20% of peanut seeds. Other fungal species were capable of invading peanut seeds only when soil densities of sections Flavi and Nigri species were low.Key words: aflatoxin, Aspergillus flavus, Aspergillus niger, Aspergillus parasiticus, fungal competition.

scholarly journals Occurrence of Aflatoxigenic Aspergillus Species in Various Varieties of Peanuts Produced in Western Kenya

2017 ◽  
Author(s):  
Menza C. Nelson ◽  
Muturi W. Margaret ◽  
Lucy Kamau
Keyword(s):  
Aspergillus Flavus ◽  
Dominant Species ◽  
Aspergillus Parasiticus ◽  
Cyclopiazonic Acid ◽  
Aspergillus Species ◽  
Western Kenya ◽  
Central District ◽  
Aspergillus Section

Aflatoxin contaminates foods including peanuts. Aflatoxin is a carcinogenic toxin mainly produced bty Aspergillus flavus. Other Aspergillus species that rarely produce aflatoxins are A. nomius and A. niger. Aflatoxin is associated with liver failure, hepatocellular carcinoma (HCC) and death. Recent studies have shown that peanuts in Kenya are highly contaminated with aflatoxins but information gaps exist on the characterization of the Aspergillus species that produce aflatoxins in peanuts in Kenya. Therefore, this gap necessitated the determination of the Aspergillus species producing aflatoxins in peanuts from the main growing districts of Busia and Kisii Central districts. One hundred and two (102) peanuts samples were collected from farmers’ in each district Aspergillus species were isolated from the peanut samples by using the dilution plate technique on modified Rose Bengal agar. Phenotypical characterization of the identified Aspergillus section flavus isolates from the peanuts samples was determined using the procedure of Mellon and Cotty. This study identified five (5) Aspergillus species as contaminants in peanuts analyzed in this study. They were Aspergillus flavus L-strain, Aspergillus flavus S-strain, Aspergillus parasiticus, Aspergillus niger and Aspergillus tamari. Overall, the occurrence of Aspergillus flavus L- strain and A. flavus S- strain were significantly higher than other species identified (H = 15.55, df = 4, P = 0.004) in peanuts from the two districts. However, A. flavus S-strain was the most dominant species identified in the study with a mean occurrence of 45.1%. Aspergillus flavus L- strain was the most common isolate (58.8%) in peanuts from Busia district while A. flavus S- strain was the most common strain (60.2%) in peanuts from Kisii Central district. Overall, the occurrence of Aspergillus flavus L strain and A. flavus S strain were significantly higher than other species identified (H = 15.55, df = 4, P = 0.004) in peanuts from the two districts. However, A. flavus S-strain was the most dominant species (F=3.15, df =25, P=0.031) with an overall mean occurrence of 45.1%. The confirmation of occurrence of other species that produce toxins such as A. niger and A. tamarii which also produces cyclopiazonic acid suggests the need to screen peanuts for other carcinogenic mycotoxins.

scholarly journals Production of Bright Greenish Yellow Fluorescence in Figs Infected by Aspergillus Species in California Orchards

Plant Disease ◽  
1998 ◽  
Vol 82 (6) ◽  
pp. 669-673 ◽  
Author(s):  
Mark A. Doster ◽  
Themis J. Michailides
Keyword(s):  
Aspergillus Flavus ◽  
Uv Light ◽  
Fungal Species ◽  
Fungal Strain ◽  
Aspergillus Species ◽  
Yellow Fluorescence ◽  
Greenish Yellow ◽  
Relationship Of ◽  
The Relationship ◽  
Aspergillus Section

The relationship of bright greenish yellow fluorescence (BGYF) of dried figs under longwave UV light to colonization by Aspergillus fungi was determined. BGYF in naturally infected figs was associated with decay by only four fungal species: the aflatoxin-producing species Aspergillus flavus (both L and S strains) and A. parasiticus, and the aflatoxin nonproducers A. tamarii and A. alliaceus. BGYF was more likely to be visible internally (after cutting open the fig) than externally. For all four species associated with BGYF, some infected figs did not show BGYF. The absence of fluorescence is probably not associated with the fungal strain or isolate involved, since isolating Aspergillus spp. from nonfluorescent figs followed by inoculating other figs with these isolates resulted in BGYF. Many of the nonfluorescent figs had small fungal colonies (<7 mm in diameter), even though some figs with large colonies were also nonfluorescent. The additional colonization of figs by other fungi did not affect the occurrence of BGYF in figs colonized by fungi in Aspergillus section Flavi. Figs infected with A. flavus or A. parasiticus and showing no BGYF were occasionally contaminated with aflatoxin, while other figs showing BGYF and infected with A. flavus or A. tamarii had no aflatoxins. Although not as promising as originally hoped, BGYF might be of use to remove aflatoxin-contaminated figs for certain specific situations in California.

Aflatoxin and cyclopiazonic acid production by Queensland isolates of Aspergillus flavus and Aspergillus parasiticus

1989 ◽  
Vol 40 (2) ◽  
pp. 395 ◽  
Author(s):  
BJ Blaney ◽  
MA Kelly ◽  
AL Tyler ◽  
MD Connole
Keyword(s):  
Aspergillus Flavus ◽  
Acid Production ◽  
Aspergillus Parasiticus ◽  
Cyclopiazonic Acid ◽  
Aflatoxin Production ◽  
Quantitative Correlation ◽  
Low Concentrations ◽  
Maize Meal ◽  
High Concentrations ◽  
Relative Prevalence

The production of aflatoxins (AFB1, AFB2, AFG1, AFG2) and cyclopiazonic acid (CPA) by 50 Queensland isolates of thc Aspergillusflavus-Aspergillus parasiticus group was examined for the purposes of chemotaxonomy and toxicology. lsolatcs were cultured on Czapek Dox agar at 28�C and examined microscopically after 5, 7 and 10 days. Conidial heads were classified as either bearing phialides only or phialidcs and metulac, while conidia were classified according to degree of roughness. Isolates were also sown onto maize meal incubated at 28�C for 28 days and assayed for aflatoxins and CPA. A. flavus types were classified as having biseriate sterigmata in 40-100% of cases and slightly to moderately rough conidia, whereas A. paraszticus types were those with 0-35% biseriate sterigmata and spikey conidia. Of the 38 isolates classed as A. flavus, 34 produced CPA (range 1-70 mg kg-1). Three isolates produced neither aflatoxins (t0.02 mg kg-1) nor CPA (< 1 mg kg-1). Seven produced CPA but no aflatoxins. The remaining 28 isolates produced AFB1 (0.02-280 mg kg-1); seven of these produced low concentrations of AFG1(0.02-0.08 mg kg-1); and only one did not produce CPA. There was no quantitative correlation between CPA and aflatoxin production by the A. fIavus isolates. Of the 12 isolates classed as A. parasiticus, none produced CPA; all produced AFB1 (4-400 mg kg-1); all produced high concentrations of AFG1 (1-400 mg kg-1). The relative prevalence of the two fungi in Queensland is discussed as a guide to the likelihood of aflatoxin and CPA contamination of different agricultural commodities.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Studies on Leukemogenic and Sarcomagenic Viruses

1970 ◽  
Vol 28 ◽  
pp. 156-157
Author(s):  
Leon Dmochowski
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Morphological Properties ◽  
Mode Of Development ◽  
Relationship Of ◽  
The Relationship

Electron microscopy has proved to be an invaluable discipline in studies on the relationship of viruses to the origin of leukemia, sarcoma, and other types of tumors in animals and man. The successful cell-free transmission of leukemia and sarcoma in mice, rats, hamsters, and cats, interpreted as due to a virus or viruses, was proved to be due to a virus on the basis of electron microscope studies. These studies demonstrated that all the types of neoplasia in animals of the species examined are produced by a virus of certain characteristic morphological properties similar, if not identical, in the mode of development in all types of neoplasia in animals, as shown in Fig. 1.

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