Impact of Exposure to Low Temperature Degrees in Field Conditions on Leaf Pigments and Chlorophyll Fluorescence in Leaves of Mango Trees

This experiment was conducted to found the connection between low temperature stress in vivo conditions (ambient-air temperature) and the changes in some physiological and biochemical events (leaf pigments and chlorophyll fluorescence) of mango trees in response to exposure to natural low temperature (cold). To verify this objective, 12 popular commonly mango cultivars (25 years old) which grown in private orchard in Fayoum Governorate, Egypt were selected for this study which carried out during the period from November to March of years; 2012 and 2013. The selected cultivars were: Alphonso, Baladi, Bullock's Heart, Helmand, Hindi Besennara, Mabrouka, Mestekawy, Nabeeh, Oweisi, Spates, Taimour and Zebda. Based on the obtained results, it can be stated that, chlorophyll (a) concentration in the leaves was significantly differed among the cultivars throughout the whole sampling times, in this respect, Helmand one gave the highest one while, and the highest one by sampling times was November one. The concentration of chlorophyll (b) was significant as effected by the effect of cultivars and sampling time recorded the highest value by the cultivar of Spates and December sample, respectively. Total chlorophyll concentration in the leaves reached its peak by the cultivar of Nabeeh and sampling time of December as compared to others. The both of Ewais cultivar and the sample of March showed the highest values of carotenoids concentration in the leaves. The levels of anthocyanin in leaves were significantly differed as affected by the cultivars and sampling times, indicating that the cultivar of Helmand and November sample recorded the highest values of anthocyanin in leaves. The greatest reductions in Fv/Fmratio were recorded at month of November and indicated that the reductions were in the order of Alphonso˃ Mabrouka˃Taimour˃ others. The effect of sampling time, cultivars and their interaction on Fv/Fm were significant, but small between some values of Fv/Fm.

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Leakage Compositional Changes Accompanying Exposure some Mango Cultivars to Low Temperature under Vitro Conditions

Journal of Horticulture and Plant Research ◽

10.18052/www.scipress.com/jhpr.10.46 ◽

2020 ◽

Vol 10 ◽

pp. 46-62

Author(s):

Ali A.S. Sayed ◽

Farouk M. Gadallah ◽

Mohamed A. Seif El-Yazal ◽

Gamal A. Abdel-Samad

Keyword(s):

Low Temperature ◽

Free Amino ◽

Soluble Sugars ◽

Ambient Air ◽

Total Soluble Sugars ◽

Total Free Amino Acids ◽

Compositional Changes ◽

The Relationship ◽

Sampling Times ◽

Fayoum Governorate

Under in vivo conditions (ambient-air temperature), the relationship between low temperature stress and the response of some different mango cultivars was monitored.Some biochemical events that occur following cold exposure of mango trees leaves were detected to evaluate their ability to acquire cold injury during exposure to low temperature. The cultivars of Alphonso, Baladi, Bullock's Heart, Helmand, Hindi Besennara, Mabrouka, Mestekawy, Nabeeh, Oweisi, Spates, Taimour and Zebdawhich grown in private orchard in Fayoum Governorate, Egypt were selected to verify this aim. This study was carried out during the period from November to March of during years; 2012 and 2013. The following results were stated: the detected leaf compositional changes were significantly differed among the tested cultivars and sampling times. In this respect, electrolytes (%), Na+, K+, inorganic phosphate (Pi), Ca2+, total soluble sugars (TSS) and total free amino acids (TFAA) concentrations were detected in leachate of fresh leaves and showed significant differences in response to the cultivars and sampling times. However, in this study, Alphonso, Bullock's Heart, Helmand, Taimour and Zebda cultivars of mango had the best result in their cold tolerance under the conditions of this study, which is not exactly in consistent with what the researcher found.

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The 28 + 28 day design is an effective sampling time for analyzing mutant frequencies in rapidly proliferating tissues of MutaMouse animals

Archives of Toxicology ◽

10.1007/s00204-021-02977-6 ◽

2021 ◽

Vol 95 (3) ◽

pp. 1103-1116

Author(s):

Francesco Marchetti ◽

Gu Zhou ◽

Danielle LeBlanc ◽

Paul A. White ◽

Andrew Williams ◽

...

Keyword(s):

Germ Cells ◽

False Negative ◽

Sampling Time ◽

Male Germ Cells ◽

Negative Results ◽

False Negative Results ◽

Detection Of Mutations ◽

The Impact ◽

Sampling Times

AbstractThe Organisation for Economic Co-Operation and Development Test Guideline 488 (TG 488) uses transgenic rodent models to generate in vivo mutagenesis data for regulatory submission. The recommended design in TG 488, 28 consecutive daily exposures with tissue sampling three days later (28 + 3d), is optimized for rapidly proliferating tissues such as bone marrow (BM). A sampling time of 28 days (28 + 28d) is considered more appropriate for slowly proliferating tissues (e.g., liver) and male germ cells. We evaluated the impact of the sampling time on mutant frequencies (MF) in the BM of MutaMouse males exposed for 28 days to benzo[a]pyrene (BaP), procarbazine (PRC), isopropyl methanesulfonate (iPMS), or triethylenemelamine (TEM) in dose–response studies. BM samples were collected + 3d, + 28d, + 42d or + 70d post exposure and MF quantified using the lacZ assay. All chemicals significantly increased MF with maximum fold increases at 28 + 3d of 162.9, 6.6, 4.7 and 2.8 for BaP, PRC, iPMS and TEM, respectively. MF were relatively stable over the time period investigated, although they were significantly increased only at 28 + 3d and 28 + 28d for TEM. Benchmark dose (BMD) modelling generated overlapping BMD confidence intervals among the four sampling times for each chemical. These results demonstrate that the sampling time does not affect the detection of mutations for strong mutagens. However, for mutagens that produce small increases in MF, sampling times greater than 28 days may produce false-negative results. Thus, the 28 + 28d protocol represents a unifying protocol for simultaneously assessing mutations in rapidly and slowly proliferating somatic tissues and male germ cells.

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In Vivo Fluorescence of Chlorophyll A: Estimation of Phytoplankton Biomass and Activity in Římov Reservoir (Czech Republic)

Water Science & Technology ◽

10.2166/wst.1993.0126 ◽

1993 ◽

Vol 28 (6) ◽

pp. 29-33 ◽

Cited By ~ 7

Author(s):

V. Vyhnálek ◽

Z. Fišar ◽

A. Fišarová ◽

J. Komárková

Keyword(s):

Czech Republic ◽

Chlorophyll Fluorescence ◽

Primary Production ◽

Chlorophyll A ◽

Phytoplankton Biomass ◽

In Vivo Fluorescence ◽

Fluorescence Of Chlorophyll A ◽

Římov Reservoir ◽

Natural Phytoplankton

The in vivo fluorescence of chlorophyll a was measured in samples of natural phytoplankton taken from the Římov Reservoir (Czech Republic) during the years 1987 and 1988. The fluorescence intensities of samples either with or without addition of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron, DCMU) were found reliable for calculating the concentration of chlorophyll a during periods when cyanobacteria were not abundant. The correction for background non-chlorophyll fluorescence appeared to be essential. No distinct correlation between a DCMU-induced increase of the fluorescence and primary production of phytoplankton was found.

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Non-invasive skin sampling of tryptophan/kynurenine ratio in vitro towards a skin cancer biomarker

Scientific Reports ◽

10.1038/s41598-020-79903-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Skaidre Jankovskaja ◽

Johan Engblom ◽

Melinda Rezeli ◽

György Marko-Varga ◽

Tautgirdas Ruzgas ◽

...

Keyword(s):

Skin Cancer ◽

Relative Increase ◽

Cancer Biomarker ◽

Cancer Diagnostics ◽

Sampling Time ◽

Skin Permeability ◽

Experimental Conditions ◽

Non Invasive

AbstractThe tryptophan to kynurenine ratio (Trp/Kyn) has been proposed as a cancer biomarker. Non-invasive topical sampling of Trp/Kyn can therefore serve as a promising concept for skin cancer diagnostics. By performing in vitro pig skin permeability studies, we conclude that non-invasive topical sampling of Trp and Kyn is feasible. We explore the influence of different experimental conditions, which are relevant for the clinical in vivo setting, such as pH variations, sampling time, and microbial degradation of Trp and Kyn. The permeabilities of Trp and Kyn are overall similar. However, the permeated Trp/Kyn ratio is generally higher than unity due to endogenous Trp, which should be taken into account to obtain a non-biased Trp/Kyn ratio accurately reflecting systemic concentrations. Additionally, prolonged sampling time is associated with bacterial Trp and Kyn degradation and should be considered in a clinical setting. Finally, the experimental results are supported by the four permeation pathways model, predicting that the hydrophilic Trp and Kyn molecules mainly permeate through lipid defects (i.e., the porous pathway). However, the hydrophobic indole ring of Trp is suggested to result in a small but noticeable relative increase of Trp diffusion via pathways across the SC lipid lamellae, while the shunt pathway is proposed to slightly favor permeation of Kyn relative to Trp.

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SARS-CoV-2-Laden Respiratory Aerosol Deposition in the Lung Alveolar-Interstitial Region Is a Potential Risk Factor for Severe Disease: A Modeling Study

Journal of Personalized Medicine ◽

10.3390/jpm11050431 ◽

2021 ◽

Vol 11 (5) ◽

pp. 431

Author(s):

Sabine Hofer ◽

Norbert Hofstätter ◽

Albert Duschl ◽

Martin Himly

Keyword(s):

Risk Factor ◽

Particle Deposition ◽

Early Stage ◽

Severe Disease ◽

Ambient Air ◽

Aerosol Deposition ◽

Pulmonary Involvement ◽

Mild Disease ◽

Disease Initiation

COVID-19, predominantly a mild disease, is associated with more severe clinical manifestation upon pulmonary involvement. Virion-laden aerosols and droplets target different anatomical sites for deposition. Compared to droplets, aerosols more readily advance into the peripheral lung. We performed in silico modeling to confirm the secondary pulmonary lobules as the primary site of disease initiation. By taking different anatomical aerosol origins into consideration and reflecting aerosols from exhalation maneuvers breathing and vocalization, the physicochemical properties of generated respiratory aerosol particles were defined upon conversion to droplet nuclei by evaporation at ambient air. To provide detailed, spatially-resolved information on particle deposition in the thoracic region of the lung, a top-down refinement approach was employed. Our study presents evidence for hot spots of aerosol deposition in lung generations beyond the terminal bronchiole, with a maximum in the secondary pulmonary lobules and a high preference to the lower lobes of both lungs. In vivo, initial chest CT anomalies, the ground glass opacities, resulting from partial alveolar filling and interstitial thickening in the secondary pulmonary lobules, are likewise localized in these lung generations, with the highest frequency in both lower lobes and in the early stage of disease. Hence, our results suggest a disease initiation right there upon inhalation of virion-laden respiratory aerosols, linking the aerosol transmission route to pathogenesis associated with higher disease burden and identifying aerosol transmission as a new independent risk factor for developing a pulmonary phase with a severe outcome.

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Effect of selenium on tea (Camellia sinensis) under low temperature: Changes in physiological and biochemical responses and quality

Environmental and Experimental Botany ◽

10.1016/j.envexpbot.2021.104475 ◽

2021 ◽

pp. 104475

Author(s):

Kehong Liu ◽

Siying Li ◽

Jingdong Han ◽

Xiaoyan Zeng ◽

Menglin Ling ◽

...

Keyword(s):

Low Temperature ◽

Camellia Sinensis ◽

Temperature Changes ◽

Biochemical Responses ◽

Physiological And Biochemical

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Analysis and Comparison of Some Low-Temperature Heat Sources for Heat Pumps

Energies ◽

10.3390/en12101853 ◽

2019 ◽

Vol 12 (10) ◽

pp. 1853 ◽

Cited By ~ 3

Author(s):

Pavel Neuberger ◽

Radomír Adamovský

Keyword(s):

Heat Transfer ◽

Low Temperature ◽

Heat Source ◽

Heat Pump ◽

Heat Exchangers ◽

Ambient Air ◽

Heat Transfer Fluid ◽

Heat Sources ◽

Ground Heat Exchangers ◽

Temperature Heat

The efficiency of a heat pump energy system is significantly influenced by its low-temperature heat source. This paper presents the results of operational monitoring, analysis and comparison of heat transfer fluid temperatures, outputs and extracted energies at the most widely used low temperature heat sources within 218 days of a heating period. The monitoring involved horizontal ground heat exchangers (HGHEs) of linear and Slinky type, vertical ground heat exchangers (VGHEs) with single and double U-tube exchanger as well as the ambient air. The results of the verification indicated that it was not possible to specify clearly the most advantageous low-temperature heat source that meets the requirements of the efficiency of the heat pump operation. The highest average heat transfer fluid temperatures were achieved at linear HGHE (8.13 ± 4.50 °C) and double U-tube VGHE (8.13 ± 3.12 °C). The highest average specific heat output 59.97 ± 41.80 W/m2 and specific energy extracted from the ground mass 2723.40 ± 1785.58 kJ/m2·day were recorded at single U-tube VGHE. The lowest thermal resistance value of 0.07 K·m2/W, specifying the efficiency of the heat transfer process between the ground mass and the heat transfer fluid, was monitored at linear HGHE. The use of ambient air as a low-temperature heat pump source was considered to be the least advantageous in terms of its temperature parameters.

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Drought resistance of hard wheat cultivars measured by a rapid chlorophyll fluorescence test

The Journal of Agricultural Science ◽

10.1017/s0021859600044257 ◽

1985 ◽

Vol 104 (3) ◽

pp. 501-504 ◽

Cited By ~ 27

Author(s):

M. Havaux ◽

R. Lannoye

Keyword(s):

Chlorophyll Fluorescence ◽

Fluorescence Induction ◽

Chlorophyll Fluorescence Induction ◽

Quenching Rate ◽

Simple Method ◽

Hard Wheat ◽

Drought Tolerant ◽

Resistant Varieties ◽

Slow Fluorescence Induction

SummaryDisks of hard wheat (Triticum durum Desf.) leaves subjected to rapid desiccation over 4 h showed noticeable changes in the shape of the in vivo chlorophyll fluorescence induction curves. In drought-sensitive varieties (such as Claridoc), water stress resulted in a strong inhibition of the slow fluorescence induction transients. In particular, the fluorescence quenching rate was markedly decreased in water-stressed leaf disks. In contrast, leaves of drought-resistant varieties (such as Aouedj) showed only minor changes in chlorophyll fluorescence. The results of this investigation suggest that the slow transient of the in vivo chlorophyll fluorescence induction phenomenon may provide a simple method for selecting drought-tolerant wheats.

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