scholarly journals Effects of Various Environmental Conditions on Pulcherrimin Production and Extracellular Enzyme Profiles of Metschnikowia pulcherrima

2020 ◽  
pp. 10-16 ◽  
Author(s):  
Tülay Turgut Genç
Keyword(s):  
Heat Stress ◽  
Extracellular Enzyme ◽  
Growth Conditions ◽  
Pigment Synthesis ◽  
Yeast Strains ◽  
Metschnikowia Pulcherrima ◽  
Different Temperatures ◽  
Beta Glucosidase ◽  
Alpha Glucosidase ◽  
Leucine Arylamidase

The aim of the present study was to determine the effect of various stress conditions on pulcherrimin pigment secretion and extracellular enzyme profiles of isolated Metschnikowia pulcherrima yeast strains. In order to analyse the effects of heat stress and osmotic stress on pulcherrimin pigment synthesis, different temperatures and NaCl concentrations were used, respectively. The enzymatic profiles of M. pulcherrima yeast strains were determined by API-ZYM. The results indicated that the amount of pigment synthesis and the localization were changed depending on the growth conditions. All yeast strains showed a high leucine arylamidase, valine arylamidase, alpha-glucosidase and beta-glucosidase activities.

scholarly journals GERMINATION AND VIGOUR IN SEEDS OF THE COWPEA IN RESPONSE TO SALT AND HEAT STRESS

2019 ◽  
Vol 32 (1) ◽  
pp. 143-151 ◽  
Author(s):  
Luma Rayane de Lima Nunes ◽  
Paloma Rayane Pinheiro ◽  
Charles Lobo Pinheiro ◽  
Kelly Andressa Peres Lima ◽  
Alek Sandro Dutra
Keyword(s):  
Salt Stress ◽  
Heat Stress ◽  
High Temperature ◽  
Low Temperature ◽  
Vigna Unguiculata ◽  
Salt Concentration ◽  
Dry Weight ◽  
Germination Percentage ◽  
Different Types ◽  
Different Temperatures

ABSTRACT Salinity is prejudicial to plant development, causing different types of damage to species, or even between genotypes of the same species, with the effects being aggravated when combined with other types of stress, such as heat stress. The aim of this study was to evaluate the tolerance of cowpea genotypes (Vigna unguiculata L. Walp.) to salt stress at different temperatures. Seeds of the Pujante, Epace 10 and Marataoã genotypes were placed on paper rolls (Germitest®) moistened with different salt concentrations of 0.0 (control), 1.5, 3.0, 4.5 and 6.0 dS m-1, and placed in a germination chamber (BOD) at temperatures of 20, 25, 30 and 35°C. The experiment was conducted in a completely randomised design, in a 3 × 4 × 5 scheme of subdivided plots, with four replications per treatment. The variables under analysis were germination percentage, first germination count, shoot and root length, and total seedling dry weight. At temperatures of 30 and 35°C, increases in the salt concentration were more damaging to germination in the Epace 10 and Pujante genotypes, while for the Marataoã genotype, damage occurred at the temperature of 20°C. At 25°C, germination and vigour in the genotypes were higher, with the Pujante genotype proving to be more tolerant to salt stress, whereas Epace 10 and Marataoã were more tolerant to high temperatures. Germination in the cowpea genotypes was more sensitive to salt stress when subjected to heat stress caused by the low temperature of 20°C or high temperature of 35°C.

scholarly journals Two Auxinic Herbicides Affect Brassica napus Plant Hormone Levels and Induce Molecular Changes in Transcription

Biomolecules ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1153
Author(s):  
Jutta Ludwig-Müller ◽  
Roman Rattunde ◽  
Sabine Rößler ◽  
Katja Liedel ◽  
Freia Benade ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Expression Patterns ◽  
Growth Conditions ◽  
Growth Stages ◽  
Auxin Response ◽  
Time Points ◽  
Genes Encoding ◽  
Different Temperatures ◽  
Indigenous Plant ◽  
Over Time

With the introduction of the new auxinic herbicide halauxifen-methyl into the oilseed rape (Brassica napus) market, there is a need to understand how this new molecule interacts with indigenous plant hormones (e.g., IAA) in terms of crop response. The aim of this study was to investigate the molecular background by using different growth conditions under which three different auxinic herbicides were administered. These were halauxifen-methyl (Hal), alone and together with aminopyralid (AP) as well as picloram (Pic). Three different hormone classes were determined, free and conjugated indole-3-acetic acid (IAA), aminocyclopropane carboxylic acid (ACC) as a precursor for ethylene, and abscisic acid (ABA) at two different temperatures and growth stages as well as over time (2–168 h after treatment). At 15 °C growth temperature, the effect was more pronounced than at 9 °C, and generally, the younger leaves independent of the developmental stage showed a larger effect on the alterations of hormones. IAA and ACC showed reproducible alterations after auxinic herbicide treatments over time, while ABA did not. Finally, a transcriptome analysis after treatment with two auxinic herbicides, Hal and Pic, showed different expression patterns. Hal treatment leads to the upregulation of auxin and hormone responses at 48 h and 96 h. Pic treatment induced the hormone/auxin response already after 2 h, and this continued for the other time points. The more detailed analysis of the auxin response in the datasets indicate a role for GH3 genes and genes encoding auxin efflux proteins. The upregulation of the GH3 genes correlates with the increase in conjugated IAA at the same time points and treatments. Also, genes for were found that confirm the upregulation of the ethylene pathway.

Characterization and Control of Erwinia spp. and Pluralibacter sp. in Tuna Salad Preparations

2019 ◽  
Vol 82 (6) ◽  
pp. 1071-1081
Author(s):  
KRISTIN BJORNSDOTTIR-BUTLER ◽  
SUSAN McCARTHY ◽  
RONALD A. BENNER
Keyword(s):  
Growth Conditions ◽  
Whole Genome ◽  
Processing Conditions ◽  
Optimum Growth ◽  
Significant Growth ◽  
Ph Values ◽  
Histamine Production ◽  
Different Temperatures ◽  
And Control ◽  
Erwinia Persicina

ABSTRACT Histamine-producing Erwinia and Pluralibacter spp. capable of producing toxic histamine levels were isolated from ingredients commonly used in tuna salad preparations. The characterization and control of these histamine-producing bacteria are necessary to prevent illness from tuna salad consumption. We confirmed the identity of two Erwinia spp. and one Pluralibacter sp. previously isolated from tuna salad ingredients through whole genome sequencing and phylogenic analysis and characterized them for growth and histamine production at different temperatures, pH values, and salt concentrations. In addition, we examined the effects of dried vinegar (DV) powder on growth and histamine production of these strains in inoculated tuna salad preparations. Optimum growth temperatures in tryptic soy broth (TSB) for the two Erwinia spp. and one Pluralibacter sp. were 30.1, 31.1, and 33.9°C, respectively, and growth in TSB was observed at 5°C for both genera. Optimum histamine production of Erwinia persicina, Erwinia spp., and Pluralibacter spp. in TSB with histidine occurred from 25 to 30°C, pH 4 to 6, and 0 to 4% NaCl. No significant growth or histamine production was observed in tuna salad preparations stored at 4°C. Growth and histamine production by Erwinia or Pluralibacter spp. was inhibited in tuna salad containing celery and onion and 2% DV, whereas significant growth and histamine production occurred in tuna salad without DV. Understanding optimum growth conditions and histamine production can provide guidance to tuna salad manufacturers in formulating products and adjusting processing conditions that minimize hazards from these histamine-producing bacteria. Addition of 2% DV to tuna salad preparations may prevent histamine production in the event of temperature abuse. HIGHLIGHTS

Factors Influencing Geosmin Production by the Cyanobacterium Oscillatoria Brevis

1988 ◽  
Vol 20 (8-9) ◽  
pp. 125-131 ◽  
Author(s):  
H. Naes ◽  
H. C. Utkilen ◽  
A. F. Post
Keyword(s):  
Environmental Factors ◽  
Dry Weight ◽  
Growth Conditions ◽  
Limited Extent ◽  
Limited Growth ◽  
Pigment Synthesis ◽  
Factors Affecting ◽  
Culture Techniques ◽  
Factors Influencing ◽  
Effect Of Inhibitors

Environmental factors affecting geosmin production by Oscillatoria brevis have been investigated under laboratory conditions using continuous culture techniques. Transition from light to nutrient limited growth conditions caused a two-fold decrease in geosmin production. However, geosmin content increased relative to pigment content (chlorophyll a and carotenoids). It has been suggested that geosmin biosynthesis in O. brevis proceeds via the isoprenoid pathway as was found in actinomycetes. Accordingly, we investigated the effect of inhibitors of the intermediate stages in this synthetic pathway in order to study the regulation of geosmin production in relation to pigment synthesis. It was concluded that geosmin seemed to function as an overflow metabolite in this pathway. Due to the only modest changes in geosmin production per dry weight compared to changes in biomass levels during light- or nutrient limited growth, contamination of eutrophic fresh waters with geosmin appears to depend mainly on the species present and its biomass level and only to a limited extent on nutrient enhanced synthesis.

Heat Stress and School Closings

PEDIATRICS ◽  
1984 ◽  
Vol 74 (2) ◽  
pp. 313-314
Author(s):  
Keyword(s):  
Heat Stress ◽  
Public Schools ◽  
Air Conditioning ◽  
Radiant Heat ◽  
Excessive Heat ◽  
Southern States ◽  
Teachers And Students ◽  
Different Temperatures ◽  
Hot Weather ◽  
American Society

During the last decade, the practice of opening public school in eary August has led to environmental stresses on students and teachers due to extremes of heat and humidity. In the South and Southwest, it is not unusual to have 15 to 20 days of 90°F(32.2°C) and relative humidity of 60% and higher during August. This puts a strain on teachers' and students' adaptability. In surveying eight southern states, J. W. Trieschmann (unpublished data, 1983) found that the availability of air conditioning in public schools ranged from 15% in some states to 30% in others. The smaller, poorer, usually rural school districts had the least access to cooling equipment. Thus, a large school population is at the mercy of the elements. This is especially significant because the majority of this population has been acclimatized to air-conditioned homes and stores, and extremes of heat discomfort are not well tolerated. Heat stress is defined as the overall effect of excessive heat on the human body. The important factors contributing to heat stress are air temperature, humidity, air movement, radiant heat, atmospheric pressure, physiologic factors (handicap or chronic disease), physical activity,1 and time exposure. Under normal conditions, temperature and humidity are the most important elements influencing comfort. The American Society of Heating, Refrigeration, Air Conditioning Engineers (ASHRAE) has published an index for determining heat stress based on human physiology, clothing, and standard room conditions.2 This index, called the "ET" or effective temperature (in Fahrenheit), is a measure of what hot weather feels like to the average person at different temperatures and humidities.

scholarly journals Subcellular distribution of glycosidases in human polymorphonuclear leucocytes

1978 ◽  
Vol 174 (1) ◽  
pp. 53-59 ◽  
Author(s):  
R F Rest ◽  
M H Cooney ◽  
J K Spitznagel
Keyword(s):  
Subcellular Distribution ◽  
Polymorphonuclear Leucocytes ◽  
Density Gradients ◽  
Glucosidase Activity ◽  
Mitochondrial Fractions ◽  
Specific Granules ◽  
Azurophil Granule ◽  
Alpha Galactosidase ◽  
Beta Glucosidase ◽  
Alpha Glucosidase

The subcellular distribution of nine glycosidases were studied in fractions of homogenized human polymorphonuclear leucocytes (neutrophils) obtained by isopycnic centrifugation through linear sucrose density gradients. The substrates were 4-methylumbelliferyl glycosides. All nine glycosides were hydrolysed by enzymes in neutrophil cytosol fractions, and by enzymes in at least one granule population. alpha-Glucosidase activity sedimented in sucrose density gradients to a point (p = 1.180 g/ml) just above the specific granules, possibly the ‘tertiary’ granule population. The peak corresponding to alpha-glucosidase did not co-sediment with, but considerably overlapped, the peak corresponding to lactoferrin, a marker for specific granules (p = 1.187 g/ml). alpha-Galactosidase activity was found primarily in heavy azurophil granules (p = 1.222 g/ml). alpha-Mannosidase activity was found primarily in light azurophil granules (p = 1.206 g/ml), following the distribution of myeloperoxidase, the commonly used azurophil granule marker. beta-Glucosidase activity was concentrated in mitochondrial fractions (p = 1.160 g/ml). All other glycosidases presented complex distributions, with activities not restricted to one granule class. Granule-associated glycosidase activities were increased 2–38 times when measured in the presence of 0.05% Triton X-100, indicating latency of the enzymes within granules.

PATTERNED GROWTH OF Si NANOWIRES: A COMPARATIVE STUDY OF VLS AND SLS

2010 ◽  
Vol 09 (03) ◽  
pp. 145-150 ◽  
Author(s):  
M. F. ZIA ◽  
J. ALI ◽  
A. NAWEED ◽  
A. S. BHATTI ◽  
S. NASEEM
Keyword(s):  
Silicon Nanowires ◽  
External Source ◽  
Growth Conditions ◽  
Si Nanowires ◽  
Experimental Conditions ◽  
Patterned Growth ◽  
Gaas Substrates ◽  
Different Temperatures ◽  
Ar Gas ◽  
Solid Liquid

In this paper, we report morphology of silicon nanowires ( Si - NWs ) grown on various surfaces and patterned substrates using Vapor–Liquid–Solid (VLS) and Solid–Liquid–Solid (SLS) techniques. It is observed that the growth conditions are critical in controlling the dimensions of wires in both techniques. In addition to this, it is also demonstrated that Si - NWs are essentially different grown on Si or GaAs substrates. For growth of Si - NWs by VLS, Si powder was evaporated in a tube furnace under Ar flow while substrates were kept at different temperatures. In SLS, experimental conditions were identical except that no external source was used. Si - NWs thus grown showed dependence on the flow rate of Ar gas and the temperature of the substrate. Interestingly, instead of only radial nannowires (NWs), nanobelts and tapered NWs were also grown on patterned Au -catalyzed GaAs surface. In the end, the analysis on the basis of existing theories of NW growth is presented. Optical properties of Si - NWs are also briefly discussed.

Influence of Growth Conditions on the Modulation Mechanism of Photoreflectance Spectra of Single InGaAs/InAlAs Quantum Wells

1993 ◽  
Vol 324 ◽  
Author(s):  
Y. Baltagi ◽  
C. Bru ◽  
T. Benyatrou ◽  
M.A. Garcia-Perez ◽  
G. Guillot ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Room Temperature ◽  
Growth Conditions ◽  
Surface Barrier ◽  
Single Quantum ◽  
Interface Defects ◽  
Growth Interruption ◽  
Different Temperatures ◽  
Inp Substrates ◽  
Pump Laser Beam

AbstractUsing Photoreflectance (PR) measurements, we have investigated In0.53Ga0.47As single quantum wells (SQW) with In0.52Al0.48As barriers grown by MBE on InP substrates. Unusual lineshapes of PR spectra are observed for the fundamental transition in some of the SQW. This phenomenon is shown to be independent on the widths of both the SQW (5nm or 10nm) and the surface barrier layer (between 65nm and 300nm). PR spectra are recorded at different temperatures and in different samples, as well as with a secondary pump laser beam. From these measurements, it is concluded that interface defects exist in the SQW grown at 525°C without growth interruption. Such defects are clearly evidenced in room temperature PR experiments and confirmed by PL measurements.

Effects of some pesticides on two yeast strains Saccharomyces cerevisiae and Metschnikowia pulcherrima

OENO One ◽  
2005 ◽  
Vol 39 (2) ◽  
pp. 67
Author(s):  
Dalal Jawich ◽  
Christo Hilan ◽  
Rachad Saliba ◽  
Roger Lteif ◽  
Pierre Strehaiano
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Reaction Rates ◽  
Aerobic Growth ◽  
Initial Value ◽  
Yeast Strains ◽  
Metschnikowia Pulcherrima

<p style="text-align: justify;">The effect of different concentrations (0-20 LMR) of six pesticides on the aerobic growth of two yeast strains (<em>Saccharomyces cerevisiae, Metschnikowia pulcherrima</em>) was analysed. The penconazole was shown as the most efficient and its effect was then studied under fermentative conditions. <em>Saccharomyces cerevisiae</em> appeared very sensitive under aerobiosis while the fermentative cultures seemed poorly affected. On the opposite, <em>Metschnikowia pulcherrima</em> was poorly affected under aerobiosis but was severely affected under fermentative conditions. The yields as well as the reaction rates decreased when initial concentrations of penconazole were increased. At least, it was shown that both strains were able to adsorb a certain ratio of the pesticide; but the pesticide was not degraded. Also for an initial value greater than 2 LMR, the residual quantity of the pesticide was above the admitted level.</p>

scholarly journals Mannosylglycerate and Di-myo-Inositol Phosphate Have Interchangeable Roles during Adaptation of Pyrococcus furiosus to Heat Stress

2014 ◽  
Vol 80 (14) ◽  
pp. 4226-4233 ◽  
Author(s):  
Ana M. Esteves ◽  
Sanjeev K. Chandrayan ◽  
Patrick M. McTernan ◽  
Nuno Borges ◽  
Michael W. W. Adams ◽  
...  
Keyword(s):  
Heat Stress ◽  
Pyrococcus Furiosus ◽  
Inositol Phosphate ◽  
Compatible Solutes ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Cell Protection ◽  
Content Type ◽  
Molecular Events ◽  
Supraoptimal Temperatures

ABSTRACTMarine hyperthermophiles accumulate small organic compounds, known as compatible solutes, in response to supraoptimal temperatures or salinities.Pyrococcus furiosusis a hyperthermophilic archaeon that grows optimally at temperatures near 100°C. This organism accumulates mannosylglycerate (MG) and di-myo-inositol phosphate (DIP) in response to osmotic and heat stress, respectively. It has been assumed that MG and DIP are involved in cell protection; however, firm evidence for the roles of these solutes in stress adaptation is still missing, largely due to the lack of genetic tools to produce suitable mutants of hyperthermophiles. Recently, such tools were developed forP. furiosus, making this organism an ideal target for that purpose. In this work, genes coding for the synthases in the biosynthetic pathways of MG and DIP were deleted by double-crossover homologous recombination. The growth profiles and solute patterns of the two mutants and the parent strain were investigated under optimal growth conditions and also at supraoptimal temperatures and NaCl concentrations. DIP was a suitable replacement for MG during heat stress, but substitution of MG for DIP and aspartate led to less efficient growth under conditions of osmotic stress. The results suggest that the cascade of molecular events leading to MG synthesis is tuned for osmotic adjustment, while the machinery for induction of DIP synthesis responds to either stress agent. MG protects cells against heat as effectively as DIP, despite the finding that the amount of DIP consistently increases in response to heat stress in the nine (hyper)thermophiles examined thus far.

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