scholarly journals Ecophysiology of Fusarium chaquense a Novel Type A Trichothecene Producer Species Isolated from Natural Grasses

Toxins ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 895
Author(s):  
Maria J. Nichea ◽  
Eugenia Cendoya ◽  
Miriam Haidukowski ◽  
Adriana M. Torres ◽  
María L. Ramirez
Keyword(s):  
High Frequency ◽  
Novel Species ◽  
Fusarium Species ◽  
Significant Risk ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Major Objective ◽  
Mycotoxin Production ◽  
Wide Range ◽  
Temperature Interactions

Fusarium chaquense, a recently formally described novel species, has been identified as an T-2 toxin (T-2), HT-2 toxin (HT-2) and other toxins producer in natural grasses (Poaceae) from Argentina. The major objective of this study was to describe the effect of water activity (aW, 0.995, 0.98, 0.95, 0.93 and 0.91), temperature (15, 25 and 30 °C) and incubation time (5, 15 and 25 days) on growth and to evaluate the production of T-2, HT-2 toxins and beauvericin (BEA) by two F. chaquense strains in a grass-based media. The results showed a wide range of conditions for F. chaquense growth and mycotoxin production. Both strains had a maximum growth rate at the highest aW (0.995) and 25 °C. Regarding mycotoxin production, more T-2 than the other analysed mycotoxins were produced by the two strains. T-2 production was favoured at 0.995 aW and 30 °C, while HT-2 production at 0.98–0.95 aW and 15 °C. The maximum levels of BEA were produced at 0.995 aW and 25–30 °C. Two-dimensional profiles of aW by temperature interactions were obtained from these data in order to identify areas where conditions indicate a significant risk of mycotoxins accumulation on grass. For its versatility on growth and mycotoxin production in a wide range of aW and temperatures, F. chaquense would have an adaptive advantage over other Fusarium species, and this would explain its high frequency of isolation in natural grasses grown up in the Chaco wetlands.

scholarly journals Methanobacterium aggregans sp. nov., a hydrogenotrophic methanogenic archaeon isolated from an anaerobic digester

2015 ◽  
Vol 65 (Pt_6) ◽  
pp. 1975-1980 ◽  
Author(s):  
Tobias Kern ◽  
Mary Linge ◽  
Michael Rother
Keyword(s):  
16S Rrna ◽  
Novel Species ◽  
Sequence Similarity ◽  
Phylogenetic Analyses ◽  
Optimal Growth ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Rrna Gene ◽  
Strictly Anaerobic ◽  
Curved Rods

A novel, strictly anaerobic, hydrogenotrophic methanogen, strain E09F.3T, was isolated from a commercial biogas plant in Germany. Cells of E09F.3T were Gram-stain-negative, non-motile, slightly curved rods, long chains of which formed large aggregates consisting of intertwined bundles of chains. Cells utilized H2+CO2 and, to a lesser extent, formate as substrates for growth and methanogenesis. The optimal growth temperature was around 40 °C; maximum growth rate was obtained at pH around 7.0 with approximately 6.8 mM NaCl. The DNA G+C content of strain E09F.3T was 39.1 mol%. Phylogenetic analyses based on 16S rRNA and mcrA gene sequences placed strain E09F.3T within the genus Methanobacterium. On the basis of 16S rRNA gene sequence similarity, strain E09F.3T was closely related to Methanobacterium congolense CT but morphological, physiological and genomic characteristics indicated that strain E09F.3T represents a novel species. The name Methanobacterium aggregans sp. nov. is proposed for this novel species, with strain E09F.3T ( = DSM 29428T = JCM 30569T) as the type strain.

scholarly journals Evaluation of Marine Synechococcus for an Algal Biorefinery in Arid Regions

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2233 ◽  
Author(s):  
Tomasz Bochenski ◽  
Tanmay Chaturvedi ◽  
Mette Hedegaard Thomsen ◽  
Jens Ejbye Schmidt
Keyword(s):  
Sodium Hydroxide ◽  
United Arab Emirates ◽  
Biomass Concentration ◽  
Local Strain ◽  
Dry Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Cell Disruption ◽  
Arid Environments ◽  
Wide Range

Implementing microalgae biorefinery in arid environments requires utilization of strains that can grow at high temperatures (above 28 °C) and salinity levels (above 30 ppt). In this study, we investigate the newly isolated seawater strain, Synechococcus, native to the United Arab Emirates, and evaluate its value as a perspective organism for cultivation (for fuel and bio-products) in regions with freshwater scarcity. The strain displayed tolerance to a wide range of temperature (22–37 °C) and salinity (20–41 ppt), with maximum biomass concentration of 0.72 g L−1 and a maximum growth rate of 82 mg L−1 d−1 at 25 °C and 33 ppt salinity. Lipids accumulation reached up to 26% of dry weight in nitrogen-depleted conditions (with 1.8 mM of nitrates addition to the media), whereas protein content exceeded 50% dry weight. In this study, harvesting is investigated using three chemical agents: Ferric chloride, sodium hydroxide, and chitosan. Cell disruption is analyzed for four distinct treatments: Enzymatic, alkaline, ultrasonic, and hydrothermal. Among tested methods, flocculation with sodium hydroxide and ultrasonication were found to be the most efficient techniques for harvesting and cell disruption, respectively. The growth characteristics of the local strain and the potential to derive protein and lipids from it makes it a promising biomass in a biorefinery context.

scholarly journals Effects of index selection on the performance and carcass composition of sheep given foods of different protein concentrationsad libitum

2004 ◽  
Vol 78 (2) ◽  
pp. 203-212 ◽  
Author(s):  
R. M. Lewis ◽  
G. C. Emmans ◽  
G. Simm
Keyword(s):  
Growth Rate ◽  
Dietary Protein ◽  
Protein Concentration ◽  
Live Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Carcass Composition ◽  
Control Line ◽  
Wide Range ◽  
Males And Females

AbstractSheep of a line selected on an index to increase carcass lean content at 150 days of age (selected (S); no. = 90), and an unselected control line (control (C); no. = 90), were given ad libitum foods of three different protein concentrations (192, 141 and 120 g/kg dry matter). Growth was measured from about 21 to 114 kg live weight. The carcasses of each line were analysed for lean, fat and bone at three widely varying weights in both males and females. Level of protein did not affect the extent to which S was superior to C in the content of fat (0.86 as much) or lean (1.08 as much) in the carcass. The fat concentration of the carcass increased, and the lean concentration decreased, as dietary protein concentration was reduced (P < 0.01). On the highest level of protein used, the S line grew 1.17 times as fast and was 1.10 times as efficient compared with C. The extent to which growth rate in S exceeded that in C was greater on the highest level of protein used (92.3 g/day) than on the two lower protein diets (26.4 g/day). The difference of 65.9 (s.e. 18.4) g/day was significant (P < 0.01). On the diet of highest protein concentration, growth was well described by a Gompertz function. The S line had an estimated maximum growth rate 1.25 times that of the C when averaged across males and females. A Spillman function was used to describe weight in terms of cumulative intake. It worked well for all three levels of dietary protein concentration. S sheep performed better than unselected sheep on foods differing in protein concentration and over a wide range of live weights, suggesting benefits are likely within the diverse farming environments found in practice.

Dynamics of Exploited Whitefish Populations and their Management with Special Reference to the Northwest Territories

1975 ◽  
Vol 32 (3) ◽  
pp. 427-448 ◽  
Author(s):  
M. C. Healey
Keyword(s):  
Growth Rate ◽  
Population Size ◽  
Total Mortality ◽  
High Growth ◽  
Maximum Growth ◽  
High Growth Rate ◽  
Maximum Growth Rate ◽  
Stock Size ◽  
Slow Growth Rate ◽  
Wide Range

Available data on mortality, growth, reproduction, and stock size in exploited and unexploited populations of lake whitefish (Coregonus clupeaformis) are reviewed with a view to understanding the dynamics of exploited populations and improving their management. Natural mortality ranged from about 0.20 to 0.80 in unexploited populations. In exploited populations total mortality was as high as 0.94. Unexploited populations showed a wide range of growth rates. Growth rate increased with increasing exploitation, and growth rate in all heavily exploited populations was similar to the most rapid growth rate shown by unexploited stocks. Heavily exploited whitefish matured at a younger age and possibly also at a smaller size than those which were unexploited. Limited data on stock size suggest that although total population size declines under heavy exploitation, the vulnerable population remains of similar size.It is concluded that whitefish respond to fluctuations in population size through compensatory changes in growth rate, the difference between growth rate in a population and maximum growth rate is a measure of its scope for compensating for increased mortality. Populations with slow growth rate and low mortality should, therefore, have the best fishery potential, while those with high growth rate and high mortality have a low fishery potential. Further, it is possible to judge the fishery potential of a population or its stage of exploitation from relatively simple measurements of mortality, growth, age structure, and maturity.

Instability of a two-dimensional compressible jet

1970 ◽  
Vol 42 (1) ◽  
pp. 151-159 ◽  
Author(s):  
C. H. Berman ◽  
J. E. Ffowcs Williams
Keyword(s):  
Broad Band ◽  
Supersonic Jet ◽  
Nonlinear Effects ◽  
Maximum Growth ◽  
Vortex Sheet ◽  
High Gain ◽  
Maximum Growth Rate ◽  
Two Dimensional ◽  
Mean Flow ◽  
Wide Range

A linearized analysis of the two-dimensional double vortex sheet model of a jet shows that inviscid jet instabilities occur over a wide range of frequencies at all jet Mach numbers. No particular frequency for maximum growth rate exists unless finite shear layer thickness effects are considered. It is suggested that the model describes the essential characteristics of a real jet disturbed by long wavelength perturbations. The idea is advanced that the jet flow constitutes a broad band amplifier of high gain. Disturbances can grow rapidly to a size when nonlinear effects bring about significant interaction with the mean flow. By seeding the jet with disturbances of a type that are highly amplified it is argued that gross features of the flow may be affected and that the jet may be rendered less noisy at high Mach number. It is argued that some of these ideas are supported by the observation that a supersonic jet diffuses at an unusually rapid rate when subject to the oscillatory condition known as ‘screech’.

Parametrically Excited Instabilities in a Magnetized Electron Plasma

1974 ◽  
Vol 52 (24) ◽  
pp. 2495-2505
Author(s):  
S. R. Seshadri
Keyword(s):  
Electric Field ◽  
High Frequency ◽  
Maximum Growth ◽  
Electron Plasma ◽  
Maximum Growth Rate ◽  
Propagation Direction ◽  
Magnetostatic Field ◽  
High Frequency Electric Field ◽  
Parametric Coupling ◽  
Uniform Plasma

The excitation of waves propagating perpendicular to the magnetostatic field in a cold, uniform plasma by an externally imposed high frequency electric field is investigated. Orientations of the external electric field parallel to the magnetostatic field as well as perpendicular to the magnetostatic field but inclined at an angle to the propagation direction are considered. In the former case, the ordinary mode is parametrically coupled-to the two branches of the extraordinary mode and in the latter case, there is coupling between the two branches of the extraordinary mode itself. This parametric coupling leads to instabilities of the interacting waves. The conditions necessary for the excitation of the parametric instabilities as well as the dependence of the maximum growth rate of the instability on the strength of the magnetostatic field are also examined.

scholarly journals Isolation, characterization, and bio-insecticidal efficiency of Ethiopian isolates of Bacillus thuringiensis against Galleria mellonella L. (Lepidoptera: Pyralidae) and tomato whitefly, Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae)

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Amha Gebremariam ◽  
Yonas Chekol ◽  
Fassil Assefa
Keyword(s):  
Growth Rate ◽  
Bacillus Thuringiensis ◽  
Bemisia Tabaci ◽  
Galleria Mellonella ◽  
Protein Detection ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Economic Damage ◽  
Percentage Mortality ◽  
Wide Range

Abstract Background Bacillus thuringiensis is a Gram-positive, rod-shaped, and spore-forming microbial entomopathogen. The silverleaf whitefly, Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae), is a worldwide important cryptic species causing serious economic damage to several vegetable crops including tomato. The aim of this study was to characterize and evaluate the bio-insecticidal effects of locally isolated Bacillus thuringiensis (Bt) against Galleria mellonella and Bemisia tabaci. Results Thirty-one isolates of Bt were obtained from 70 soil samples based on cultural characterization coupled with insecticidal crystal protein detection. All of the 31 bacterial isolates were pre-screened for their bio-insecticidal property against the greater wax moth, Galleria mellonella L. larvae. Only 20 (64.5%) isolates were virulent to G. mellonella with a percentage mortality that ranged from 2.50 to 95%. The groEL gene sequences of all 20 entomopathogenic indigenous isolates displayed 99–100% similarity with Bt isolates. Bioassay evaluation of 12 selected isolates against 3rd to 4th nymphal instars of B. tabaci with spore-crystal suspensions of 1 × 109 spores/ml caused 0 to 31.25%, 0 to 57%, and 0 to 82.5% percentage mortality within 48, 96, and 144 h accordingly. Among isolates of Bt, isolate AAUDS-16 had the highest virulence, followed by the isolate AAUES-69D with LC50 values of 9.67 × 106 spores/ml and 1.16 × 107 spores/ml, respectively. The virulent isolates were tested for their growth response to a different temperature range between 15 and 40 °C. All isolates showed a maximum growth rate around 30 °C. Conclusions Bt isolates of AAUES-69D and AAUDS-16 displayed high insecticidal potential against B. tabaci nymphs and G. mellonella larvae, and showed a maximum growth rate in a wide range of temperature. High virulence and temperature-tolerant isolates should be important candidates for diverse insecticidal toxin studies.

scholarly journals Assessing the sustainability of harvest of the European Turtle-dove along the European western flyway

2019 ◽  
Vol 30 (4) ◽  
pp. 506-521 ◽  
Author(s):  
HERVÉ LORMÉE ◽  
CHRISTOPHE BARBRAUD ◽  
WILL PEACH ◽  
CARLES CARBONERAS ◽  
JEAN DOMINIQUE LEBRETON ◽  
...  
Keyword(s):  
Action Plan ◽  
Maximum Growth ◽  
Single Species ◽  
European Population ◽  
Maximum Growth Rate ◽  
Adult Survival ◽  
Hunting Bag ◽  
Management Objectives ◽  
Wide Range ◽  
Turtle Dove

SummaryWith a decline exceeding 30% over three generations, the once-common European Turtle-dove is now considered globally threatened by IUCN. As a legal game species in 10 European countries, the recent International Single Species Action Plan for this species highlighted the need to carry out an assessment of the sustainability of current levels of hunting. In 2013–2014, the Western European population was estimated at 1.3–2.1 million pairs, and the hunting bag in the same region to be 1.1 million birds. Using the Demographic Invariant Method, we assessed whether current levels of hunting harvest within Europe constitute overexploitation of the western flyway European Turtle-dove population. We calculated the maximum growth rate λmax that a population might achieve in the absence of any additive mortality. Then we estimated the potential maximum harvestable population fraction (P) allowed by excess population growth. We explored a wide range of plausible scenarios relating to assumed demographic rates, geographic scope of the flyway and management objectives. λmax was estimated to lie between 1.551 and 1.869. Current levels of hunting along the western flyway are more than double the sustainable fraction (P) under all suitably conservative scenarios, and only fall below this threshold under the most restrictive assumptions. We conclude that current levels of legal hunting along the western flyway are unlikely to be sustainable. Reducing uncertainty associated with assessments of the sustainability of turtle dove hunting will require improved information on (in order of decreasing importance) current levels of hunting, adult survival, age structure and population size.

scholarly journals Variation in the fatty acid profiles of two cold water diatoms grown under different temperature, light, and nutrient regimes

2021 ◽  
Author(s):  
Kristian Spilling ◽  
Jukka Seppälä ◽  
Dagmar Schwenk ◽  
Heiko Rischer ◽  
Timo Tamminen
Keyword(s):  
Nutrient Limitation ◽  
Cold Water ◽  
Photosynthetic Apparatus ◽  
Dry Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Omega 3 Fatty Acids ◽  
Omega 3 ◽  
Wide Range ◽  
Different Temperatures

AbstractThere is a growing demand for marine omega-3 fatty acids (FAs) that is produced in high amounts by some microalgae. Here we determined the FA profiles of two cold water adapted diatoms, Chaetoceros wighamii and Thalassiosira baltica. The cultures were acclimated to different temperatures (3, 7, 11, 15, and 19 °C) and irradiance (20, 40, 130, and 450 μmol photons m−2 s−1) and the FA profiles were determined in exponential and stationary growth phases, the latter induced by different nutrient limitation (N, P, and Si). The maximum growth rate was obtained by both species at 11 °C, ≥ 130 μmol photons m−2 s−1 and was 0.8 day−1 and 0.6 day−1 for C. wighamii and T. baltica, respectively. Both species contained relatively high amounts of eicosapentaenoic acid (EPA). Thalassiosira baltica accumulated maximally ~ 30 mg EPA g−1 ash-free dry weight (AFDW) under Si-limitation. The content of docosahexaenoic acid (DHA) was lower, reaching up to 4 mg DHA g−1 AFDW in T. baltica. The concentration of EPA correlated positively with the chlorophyll a:carbon ratio, suggesting that it is bound to membranes in the photosynthetic apparatus and the EPA content in T. baltica was high enough to consider it as a potent candidate for cultivation under cold (< 15 °C) conditions. Covering a wide range of environmental conditions, the strongest differentiation in FA profiles was observed between the species with the growth phase/nutrient limitation pattern as the second most important driver of the FA composition.

Effects of charge non-neutrality and finite beta on the electron temperature gradient modes in Tokamaks

2004 ◽  
Vol 82 (3) ◽  
pp. 167-176
Author(s):  
A Hirose ◽  
D Z Liu ◽  
S Livingstone ◽  
A Hirose
Keyword(s):  
Growth Rate ◽  
Temperature Gradient ◽  
Electron Temperature ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Skin Depth ◽  
Electron Temperature Gradient ◽  
Wide Range ◽  
Length Estimate ◽  
52.35 Py

Local kinetic analysis of the electron temperature gradient (ETG) mode in Tokamaks indicates that the effects of charge non-neutrality are significant in the parameter regime of Tokamaks. The maximum growth rate occurs at (k/kDe)2 [Formula: see text] 0.5 when the electron temperature and density are varied over a wide range. The growth rate becomes dependent on the β factor even though the ETG mode is predominantly electrostatic. Finite β stabilization of the ETG mode requires a large ballooning parameter so as to cause an effective drift reversal. Mixing length estimate yields an electron thermal diffusivity χe [Formula: see text] qνTe (c/ωpe)2 [Formula: see text] / Ln where c/ωpe is the electron skin depth. PACS Nos.: 52.65.Tt, 52.55.Fa, 52.35.Py

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