Insights into the impact of increasing temperature, light intensity, and UV-B exposure on the circadian rhythm of microcystin production and release, and the expression of mcy genes in the cyanobacterium Microcystis aeruginosa

2021 ◽  
Author(s):  
Micheline Kézia Cordeiro‑Araújo ◽  
Adriana Sturion Lorenzi ◽  
Mathias Ahii Chia ◽  
Eliane Christina Mota ◽  
Maria do Carmo Bittencourt-Oliveira
Keyword(s):  
Circadian Rhythm ◽  
Light Intensity ◽  
Microcystis Aeruginosa ◽  
Microcystin Production ◽  
Increasing Temperature ◽  
The Impact ◽  
Mcy Genes

Circadian Rhythm of Locomotion and its Temperature Dependence in Blattella Germanica

1971 ◽  
Vol 54 (1) ◽  
pp. 187-198
Author(s):  
HANS DREISIG ◽  
ERIK TETENS NIELSEN
Keyword(s):  
Circadian Rhythm ◽  
Light Intensity ◽  
Temperature Dependence ◽  
Blattella Germanica ◽  
Temperature Dependent ◽  
Continuous Darkness ◽  
Expected Time ◽  
Different Temperatures ◽  
Free Running ◽  
Increasing Temperature

1. The activity in Blattella germanica was investigated under standard conditions. Periods of latency and increment were recognized. 2. The free-running rhythm in continuous darkness was determined at different temperatures and showed about the same period. The free-running rhythm in continous light could not be determined unless the light intensity was extremely low. 3. The period of activity was not released immediately after a change from light to darkness if this was advanced in relation to the normal time. The activity was then only slightly advanced. 4. Delay of the onset of darkness caused the activity to diminish gradually after the usual time of change from light to dark. 5. If the temperature was lowered some time before the expected time of activity in continuous darkness the activity was advanced much more than normally. If the temperature was raised the activity was delayed. 6. Based upon these and other studies, a theory is advanced which explains the activity rhythms in insects as being the result of the interaction between a gradually increasing, temperature-dependent sensitization and different thresholds of release determined by light and temperature. A theory is propounded concerning the temperature-independence of the free-running rhythm in continuous darkness, assuming a temperature-dependent threshold of release.

Temperature Dependence of Hole Impact Ionization Coefficient in 4H-SiC Photodiodes

2009 ◽  
Vol 615-617 ◽  
pp. 311-314 ◽  
Author(s):  
W.S. Loh ◽  
J.P.R. David ◽  
B.K. Ng ◽  
Stanislav I. Soloviev ◽  
Peter M. Sandvik ◽  
...  
Keyword(s):  
Phonon Scattering ◽  
Impact Ionization ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Different Temperatures ◽  
Ionization Coefficients ◽  
Increasing Temperature ◽  
The Impact ◽  
Good Agreement ◽  
Ionization Rates

Hole initiated multiplication characteristics of 4H-SiC Separate Absorption and Multiplication Avalanche Photodiodes (SAM-APDs) with a n- multiplication layer of 2.7 µm were obtained using 325nm excitation at temperatures ranging from 300 to 450K. The breakdown voltages increased by 200mV/K over the investigated temperature range, which indicates a positive temperature coefficient. Local ionization coefficients, including the extracted temperature dependencies, were derived in the form of the Chynoweth expression and were used to predict the hole multiplication characteristics at different temperatures. Good agreement was obtained between the measured and the modeled multiplication using these ionization coefficients. The impact ionization coefficients decreased with increasing temperature, corresponding to an increase in breakdown voltage. This result agrees well with the multiplication characteristics and can be attributed to phonon scattering enhanced carrier cooling which has suppressed the ionization process at high temperatures. Hence, a much higher electric field is required to achieve the same ionization rates.

scholarly journals Impact of Inorganic Carbon Availability on Microcystin Production by Microcystis aeruginosa PCC 7806

2007 ◽  
Vol 73 (21) ◽  
pp. 6994-7002 ◽  
Author(s):  
Sabine J�hnichen ◽  
Tilo Ihle ◽  
Thomas Petzoldt ◽  
J�rgen Benndorf
Keyword(s):  
Microcystis Aeruginosa ◽  
Type Strain ◽  
Inorganic Carbon ◽  
Wild Type Strain ◽  
Light Cycle ◽  
Variable Fluorescence ◽  
Wild Type ◽  
Dark Light ◽  
Sodium Dependent ◽  
The Impact

ABSTRACT Batch culture experiments with the cyanobacterium Microcystis aeruginosa PCC 7806 were performed in order to test the hypothesis that microcystins (MCYSTs) are produced in response to a relative deficiency of intracellular inorganic carbon (Ci,i). In the first experiment, MCYST production was studied under increased Ci,i deficiency conditions, achieved by restricting sodium-dependent bicarbonate uptake through replacement of sodium bicarbonate in the medium with its potassium analog. The same experimental approach was used in a second experiment to compare the response of the wild-type strain M. aeruginosa PCC 7806 with its mcyB mutant, which lacks the ability to produce MCYSTs. In a third experiment, the impact of varying the Ci,i status on MCYST production was examined without suppressing the sodium-dependent bicarbonate transporter; instead, a detailed investigation of a dark-light cycle was performed. In all experiments, a relative Ci,i deficiency was indicated by an elevated variable fluorescence signal and led to enhanced phycocyanin cell quotas. Higher MCYST cell quotas (in the first and third experiments) and increased total (intracellular plus extracellular) MCYST production (in the first experiment) were detected with increased Ci,i deficiency. Furthermore, the MCYST-producing wild-type strain and its mcyB mutant showed basically the same response to restrained inorganic carbon uptake, with elevated variable fluorescence and phycocyanin cell quotas with increased Ci,i deficiency. The response of the wild type, however, was distinctly stronger and also included elevated chlorophyll a cell quotas. These differences indicate the limited ability of the mutant to adapt to low-Ci,i conditions. We concluded that MCYSTs may be involved in enhancing the efficiency of the adaptation of the photosynthetic apparatus to fluctuating inorganic carbon conditions in cyanobacterial cells.

Insulin resistance induced by long-term sleep deprivation in rhesus macaques can be attenuated by Bifidobacterium

2021 ◽  
Author(s):  
Ying Zhao ◽  
Yan Shu ◽  
Ning Zhao ◽  
Zili Zhou ◽  
Xiong Jia ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Circadian Rhythm ◽  
Blood Glucose ◽  
Glucose Metabolism ◽  
Sleep Deprivation ◽  
Rhesus Macaques ◽  
Intravenous Glucose ◽  
Increased Risk ◽  
The Impact

Long-term sleep deprivation (SD) is a bad lifestyle habit, especially among specific occupational practitioners, characterized by circadian rhythm misalignment and abnormal sleep/wake cycles. SD is closely associated with an increased risk of metabolic disturbance, particularly obesity and insulin resistance. The incretin hormone, glucagon-like peptide-1 (GLP-1), is a critical insulin release determinant secreted by the intestinal L-cell upon food intake. Besides, the gut microbiota participates in metabolic homeostasis and regulates GLP-1 release in a circadian rhythm manner. As a commonly recognized intestinal probiotic, Bifidobacterium has various clinical indications regarding its curative effect. However, few studies have investigated the effect of Bifidobacterium supplementation on sleep disorders. In the present study, we explored the impact of long-term SD on the endocrine metabolism of rhesus monkeys and determined the effect of Bifidobacterium supplementation on the SD-induced metabolic status. Lipids concentrations, body weight, fast blood glucose, and insulin levels increased after SD. Furthermore, after two months of long-term SD, the intravenous glucose tolerance test (iVGTT) showed that the glucose metabolism was impaired and the insulin sensitivity decreased. Moreover, one month of Bifidobacterium oral administration significantly reduced blood glucose and attenuated insulin resistance in rhesus macaques. Overall, our results suggested that Bifidobacterium might be used to alleviate SD-induced aberrant glucose metabolism and improve insulin resistance. Also, it might help in better understanding the mechanisms governing the beneficial effects of Bifidobacterium.

Evaluation of changes in Microcystis aeruginosa growth and microcystin production by urea via transcriptomic surveys

2019 ◽  
Vol 655 ◽  
pp. 181-187 ◽  
Author(s):  
Yanping Zhou ◽  
Xufeng Zhang ◽  
Xuan Li ◽  
Peili Jia ◽  
Ruihua Dai
Keyword(s):  
Microcystis Aeruginosa ◽  
Microcystin Production

scholarly journals Using a two-layered sphere model to investigate the impact of gas vacuoles on the inherent optical properties of <i>Microcystis aeruginosa</i>

2013 ◽  
Vol 10 (12) ◽  
pp. 8139-8157 ◽  
Author(s):  
M. W. Matthews ◽  
S. Bernard
Keyword(s):  
Optical Properties ◽  
Microcystis Aeruginosa ◽  
Cyanobacterial Blooms ◽  
Shell Layer ◽  
Sphere Model ◽  
Homogeneous Population ◽  
Chl A ◽  
Inherent Optical Properties ◽  
Gas Vacuoles ◽  
The Impact

Abstract. A two-layered sphere model is used to investigate the impact of gas vacuoles on the inherent optical properties (IOPs) of the cyanophyte Microcystis aeruginosa. Enclosing a vacuole-like particle within a chromatoplasm shell layer significantly altered spectral scattering and increased backscattering. The two-layered sphere model reproduced features in the spectral attenuation and volume scattering function (VSF) that have previously been attributed to gas vacuoles. This suggests the model is good at least as a first approximation for investigating how gas vacuoles alter the IOPs. Measured Rrs was used to provide a range of values for the central value of the real refractive index, 1 + ε, for the shell layer using measured IOPs and a radiative transfer model. Sufficient optical closure was obtained for 1 + ε between 1.1 and 1.14, which had corresponding Chl a-specific phytoplankton backscattering, bbφ*, between 3.9 and 7.2 × 10−3 m2 mg−1 at 510 nm. The bbφ* values are in close agreement with the literature and in situ particulate backscattering measurements. Rrs simulated for a population of vacuolate cells was greatly enlarged relative to a homogeneous population. A sensitivity analysis of empirical algorithms for estimating Chl a in eutrophic/hypertrophic waters suggests these are robust under variable constituent concentrations and likely to be species-sensitive. The study confirms that gas vacuoles cause significant increase in backscattering and are responsible for the high Rrs values observed in buoyant cyanobacterial blooms. Gas vacuoles are therefore one of the most important bio-optical substructures influencing the IOPs in phytoplankton.

scholarly journals Variation of Runoff and Runoff Components of the Upper Shule River in the Northeastern Qinghai–Tibet Plateau under Climate Change

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3357
Author(s):  
Jinkui Wu ◽  
Hongyuan Li ◽  
Jiaxin Zhou ◽  
Shuya Tai ◽  
Xueliang Wang
Keyword(s):  
Climate Change ◽  
Sustainable Use ◽  
Reduction Rate ◽  
Northwest China ◽  
Tibet Plateau ◽  
Glacier Area ◽  
Rainfall Runoff ◽  
Total Runoff ◽  
Increasing Temperature ◽  
The Impact

Quantifying the impact of climate change on hydrologic features is essential for the scientific planning, management and sustainable use of water resources in Northwest China. Based on hydrometeorological data and glacier inventory data, the Spatial Processes in Hydrology (SPHY) model was used to simulate the changes of hydrologic processes in the Upper Shule River (USR) from 1971 to 2020, and variations of runoff and runoff components were quantitatively analyzed using the simulations and observations. The results showed that the glacier area has decreased by 21.8% with a reduction rate of 2.06 km2/a. Significant increasing trends in rainfall runoff, glacier runoff (GR) and baseflow indicate there has been a consistent increase in total runoff due to increasing rainfall and glacier melting. The baseflow has made the largest contribution to total runoff, followed by GR, rainfall runoff and snow runoff, with mean annual contributions of 38%, 28%, 18% and 16%, respectively. The annual contribution of glacier and snow runoff to the total runoff shows a decreasing trend with decreasing glacier area and increasing temperature. Any increase of total runoff in the future will depend on an increase of rainfall, which will exacerbate the impact of drought and flood disasters.

Comprehensive assessment of three typical antibiotics on cyanobacteria (Microcystis aeruginosa): The impact and recovery capability

2018 ◽  
Vol 160 ◽  
pp. 84-93 ◽  
Author(s):  
Yingxiang Du ◽  
Jing Wang ◽  
Fengyi Zhu ◽  
Dina Mai ◽  
Zhongrun Xiang ◽  
...  
Keyword(s):  
Microcystis Aeruginosa ◽  
Comprehensive Assessment ◽  
The Impact
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