Factors contributing to ice nucleation and sequential freezing of leaves in wheat

Abstract Main conclusion Anatomical, metabolic and microbial factors were identified that contribute to sequential freezing in wheat leaves and likely contribute to supercooling in the youngest leaves and potentially meristematic regions. Abstract Infrared thermography (IR) has been used to observe wheat leaves freezing independently and in an age-related sequence with older leaves freezing first. To determine mechanisms that might explain this sequence of freezing several analytical approaches were used: (1) The size of xylem vessels, in proximity to where freezing initiated, was measured to see if capillary freezing point depression explained sequential freezing. The sequence of freezing in the four youngest leaves was correlated, with the largest vessels freezing first. (2) Carbohydrate and amino acids were analyzed to determine if solute concentrations as well as interactions with membranes explained the freezing sequence. Sucrose was highly correlated to the freezing sequence for all leaves suggesting a prominent role for this sugar as compared to other simple sugars and fructans. Among individual free amino acids proline and serine were correlated to the freezing sequence, with younger leaves having the highest concentrations. (3) Microflora within and on leaf surfaces were determined to measure potential freezing initiation. Levels of bacteria and fungi were correlated to the freezing sequence for all leaves, and species or genera associated with high ice nucleation activity were absent in younger leaves. Moisture content and transcript expression of ice binding proteins were also measured. As expected, our results show that no single mechanism explains the freezing sequence observed via infrared analyses. While these multiple mechanisms are operative at different levels according to the leaf age, they seem to converge when it comes to the protection of vital meristematic tissues. This provides potential phenotypic characters that could be used by breeders to develop more winter-hardy genotypes.

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Cultivable halotolerant ice-nucleating bacteria and fungi in coastal precipitation

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-9031-2021 ◽

2021 ◽

Vol 21 (11) ◽

pp. 9031-9045

Author(s):

Charlotte M. Beall ◽

Jennifer M. Michaud ◽

Meredith A. Fish ◽

Julie Dinasquet ◽

Gavin C. Cornwell ◽

...

Keyword(s):

Freezing Point ◽

Cloud Droplet ◽

Freezing Temperature ◽

Ice Nucleation ◽

Growth Media ◽

Marine Aerosol ◽

Marine Microbes ◽

Potential Source ◽

Sea Spray Aerosol ◽

Bacteria And Fungi

Abstract. Ice-nucleating particles (INPs) represent a rare subset of aerosol particles that initiate cloud droplet freezing at temperatures above the homogenous freezing point of water (−38 ∘C). Considering that the ocean covers 71 % of the Earth's surface and represents a large potential source of INPs, it is imperative that the identities, properties and relative emissions of ocean INPs become better understood. However, the specific underlying drivers of marine INP emissions remain largely unknown due to limited observations and the challenges associated with isolating rare INPs. By generating isolated nascent sea spray aerosol (SSA) over a range of biological conditions, mesocosm studies have shown that marine microbes can contribute to INPs. Here, we identify 14 (30 %) cultivable halotolerant ice-nucleating microbes and fungi among 47 total isolates recovered from precipitation and aerosol samples collected in coastal air in southern California. Ice-nucleating (IN) isolates collected in coastal air were nucleated ice from extremely warm to moderate freezing temperatures (−2.3 to −18 ∘C). While some Gammaproteobacteria and fungi are known to nucleate ice at temperatures as high as −2 ∘C, Brevibacterium sp. is the first Actinobacteria found to be capable of ice nucleation at a relatively high freezing temperature (−2.3 ∘C). Air mass trajectory analysis demonstrates that marine aerosol sources were dominant during all sampling periods, and phylogenetic analysis indicates that at least 2 of the 14 IN isolates are closely related to marine taxa. Moreover, results from cell-washing experiments demonstrate that most IN isolates maintained freezing activity in the absence of nutrients and cell growth media. This study supports previous studies that implicated microbes as a potential source of marine INPs, and it additionally demonstrates links between precipitation, marine aerosol and IN microbes.

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Variation of amino acids in Prunus persica cultivars leaves with regard to leaf age

Scientia Horticulturae ◽

10.1016/j.scienta.2021.110001 ◽

2021 ◽

Vol 281 ◽

pp. 110001

Author(s):

Samia Dabbou ◽

Samira Maatallah ◽

Andrea Antonelli ◽

Giuseppe Montevecchi

Keyword(s):

Amino Acids ◽

Prunus Persica ◽

Leaf Age

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Association of Human Plasma Metabolomics with Delayed Dark Adaptation in Age-Related Macular Degeneration

Metabolites ◽

10.3390/metabo11030183 ◽

2021 ◽

Vol 11 (3) ◽

pp. 183

Author(s):

Kevin M Mendez ◽

Janice Kim ◽

Inês Laíns ◽

Archana Nigalye ◽

Raviv Katz ◽

...

Keyword(s):

Amino Acids ◽

Fatty Acid ◽

Macular Degeneration ◽

Dark Adaptation ◽

Ultra Performance Liquid Chromatography ◽

Cross Sectional Study ◽

Age Related Macular Degeneration ◽

Cross Sectional ◽

Age Related ◽

Vitreoretinal Disease

The purpose of this study was to analyze the association between plasma metabolite levels and dark adaptation (DA) in age-related macular degeneration (AMD). This was a cross-sectional study including patients with AMD (early, intermediate, and late) and control subjects older than 50 years without any vitreoretinal disease. Fasting blood samples were collected and used for metabolomic profiling with ultra-performance liquid chromatography–mass spectrometry (LC-MS). Patients were also tested with the AdaptDx (MacuLogix, Middletown, PA, USA) DA extended protocol (20 min). Two measures of dark adaptation were calculated and used: rod-intercept time (RIT) and area under the dark adaptation curve (AUDAC). Associations between dark adaption and metabolite levels were tested using multilevel mixed-effects linear modelling, adjusting for age, gender, body mass index (BMI), smoking, race, AMD stage, and Age-Related Eye Disease Study (AREDS) formulation supplementation. We included a total of 71 subjects: 53 with AMD (13 early AMD, 31 intermediate AMD, and 9 late AMD) and 18 controls. Our results revealed that fatty acid-related lipids and amino acids related to glutamate and leucine, isoleucine and valine metabolism were associated with RIT (p < 0.01). Similar results were found when AUDAC was used as the outcome. Fatty acid-related lipids and amino acids are associated with DA, thus suggesting that oxidative stress and mitochondrial dysfunction likely play a role in AMD and visual impairment in this condition.

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Formaldehyde and De/Methylation in Age-Related Cognitive Impairment

Genes ◽

10.3390/genes12060913 ◽

2021 ◽

Vol 12 (6) ◽

pp. 913

Author(s):

Ting Li ◽

Yan Wei ◽

Meihua Qu ◽

Lixian Mou ◽

Junye Miao ◽

...

Keyword(s):

Amino Acids ◽

Cell Proliferation ◽

Cognitive Impairment ◽

Metabolic Pathways ◽

Memory Formation ◽

Epigenetic Alterations ◽

Diagnostic Biomarker ◽

Reactive Substance ◽

Age Related ◽

Novel Therapeutic

Formaldehyde (FA) is a highly reactive substance that is ubiquitous in the environment and is usually considered as a pollutant. In the human body, FA is a product of various metabolic pathways and participates in one-carbon cycle, which provides carbon for the synthesis and modification of bio-compounds, such as DNA, RNA, and amino acids. Endogenous FA plays a role in epigenetic regulation, especially in the methylation and demethylation of DNA, histones, and RNA. Recently, epigenetic alterations associated with FA dysmetabolism have been considered as one of the important features in age-related cognitive impairment (ARCI), suggesting the potential of using FA as a diagnostic biomarker of ARCI. Notably, FA plays multifaceted roles, and, at certain concentrations, it promotes cell proliferation, enhances memory formation, and elongates life span, effects that could also be involved in the aetiology of ARCI. Further investigation of and the regulation of the epigenetics landscape may provide new insights about the aetiology of ARCI and provide novel therapeutic targets.

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METABOLISM OF AROMATIC COMPOUNDS IN HEALTHY AND RUST-INFECTED PRIMARY LEAVES OF WHEAT: II. STUDIES WITH L-PHENYLALANINE-U-14C, L-TYROSINE-U-14C, AND FERULATE-U-14C

Canadian Journal of Botany ◽

10.1139/b67-233 ◽

1967 ◽

Vol 45 (11) ◽

pp. 2137-2153 ◽

Cited By ~ 23

Author(s):

A. Fuchs ◽

R. Rohringer ◽

D. J. Samborski

Keyword(s):

Amino Acids ◽

Stem Rust ◽

Aromatic Compounds ◽

The Other ◽

Major Portion ◽

Insoluble Residue ◽

Resistant Reaction ◽

Wheat Leaves

Wheat leaves infected with stem rust, especially those of susceptible plants, contained more phenylalanine and tyrosine than healthy leaves. The utilization of phenylalanine was increased in both the susceptible and resistant reaction, but the utilization of tyrosine was increased only in the susceptible reaction. No evidence of interconversion of these amino acids was obtained.In n-butanol extracts, which contained glycosides, many constituents were labelled after feeding of L-phenylalanine-U-14C. Most of the n-butanol extractives from resistant-reacting leaves contained more label than those from susceptible-reacting leaves or from healthy leaves. However, one of the n-butanol extractives from susceptible-reacting leaves was 5–10 times as active as that isolated from the other tissues.With L-phenylalanine-U-14C and ferulate-U-14C as precursors, more activity was recovered in insoluble than in soluble esters (of ferulate and p-coumarate). With L-tyrosine-U-14C as precursor, the reverse was observed. After infection, the proportion of label in insoluble esters increased more in resistant leaves than it did in susceptible leaves, regardless of the precursor used.A major portion of the activity from these precursors was recovered in the insoluble residue that contained protein and other polymers. In the experiment with L-phenylalanine-U-14C, this residue was fractionated into protein and non-hydrolyzable material. Susceptible-reacting leaves contained equal amounts of activity in these fractions, while resistant-reacting leaves incorporated 2.5 times as much activity into the non-hydrolyzable material as into protein.

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GESTATIONAL AGE-RELATED REFERENCE VALUES FOR AMNIOTIC FLUID AMINO ACIDS: A USEFUL TOOL FOR PRENATAL DIAGNOSIS OF AMINOACIDOPATHIES

Prenatal Diagnosis ◽

10.1002/(sici)1097-0223(199607)16:7<623::aid-pd921>3.0.co;2-5 ◽

1996 ◽

Vol 16 (7) ◽

pp. 623-628 ◽

Cited By ~ 9

Author(s):

D. RABIER ◽

B. CHADEFAUX-VEKEMANS ◽

J. F. OURY ◽

J. AUPETIT ◽

J. BARDET ◽

...

Keyword(s):

Amino Acids ◽

Prenatal Diagnosis ◽

Amniotic Fluid ◽

Reference Values ◽

Gestational Age ◽

Age Related

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Amino Acids Profiling in Fruit Juices by High Performance Liquid Chromatography: A Review

International Journal of Research in Pharmaceutical Sciences ◽

10.26452/ijrps.v11ispl4.4552 ◽

2020 ◽

Vol 11 (SPL4) ◽

pp. 2756-2767

Author(s):

Vijaya Vemani ◽

Mounika P ◽

Poulami Das ◽

Anand Kumar Tengli

Keyword(s):

Amino Acids ◽

High Performance Liquid Chromatography ◽

Liquid Chromatography ◽

High Performance ◽

Amino Acid Content ◽

Building Blocks ◽

Fruit Juices ◽

The Body ◽

Total Amino Acid ◽

Analytical Approaches

In the preservation of normal physiological functions, the building blocks of the body called amino acids play a crucial role. A number of valuable and nutritional phytoconstituents are contained in fruit juices, such as vitamins, minerals, microelements, organic acids, antioxidants, flavonoids, amino acids and other components. Due to the growing population and demand, the quality of fruit juices is decreasing. One of the unethical and harmful practices called adulteration or food fraudulence has been adopted by most food and beverage industries. The amino acids which is one of the most important phytochemicals of fruit and fruit juices which affects the organoleptic properties like color, odor, and taste of juices and also helps in authenticity process from governing bodies by providing total amino acid content. Consequently, the main aim of the present review work is to provide information regarding the importance of amino acids, how they are adulterated, the potential analytical approach to detected amino acids and which methods are generally accepted method by the food industries. According to the literature review, we presume that reverse phased high-performance liquid chromatography with pre-column derivatization was the most adopted method for quality checking due to its advantages over other old and recent analytical approaches like simple, rapid, cost-effective nature, less / no sample matrix effect with high sensitivity, accuracy, and precision.

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The Impact of (bio-)organic substances on the ice nucleation activity of the K-feldspar microcline in aqueous solutions

10.5194/acp-2021-806 ◽

2021 ◽

Author(s):

Kristian Klumpp ◽

Claudia Marcolli ◽

Thomas Peter

Keyword(s):

Amino Acids ◽

Citric Acid ◽

Carboxylic Acids ◽

Water Activity ◽

Active Sites ◽

Ice Nucleation ◽

Organic Substances ◽

Nucleation Activity ◽

Ice Nucleation Activity ◽

The Impact

Abstract. Potassium-feldspars (K-feldspars), such as microcline, are considered key dust minerals inciting ice nucleation in mixed phase clouds. Besides the high ice nucleation activity of microcline, recent studies also revealed a high sensi-tivity of microcline towards interaction with solutes on its surface. Here, we investigate the effect of organic and bio-organic substances on the ice nucleation activity of microcline, with the aim to better understand the underlying sur-face interactions. We performed immersion freezing experiments with microcline in solutions of three carboxylic acids, five amino acids and two polyols to represent these compound classes. By means of a differential scanning calorimeter we investigated the freezing of emulsified droplets of microcline suspended in various solutions. Depend-ing on the type of solute, different effects were observed. In the case of carboxylic acids (acetic, oxalic and citric acid), the measured heterogeneous onset temperatures, Thet, showed no significant deviation from the behavior pre-dicted by the water activity criterion, Thet(aw) = Tmelt(aw+Δaw), which relates Thet with the melting point temperature Tmelt via a constant water activity offset Δaw. While this behavior could be interpreted as a lack of interaction of the solute molecules with the surface, the carboxylic acids caused the fraction of heterogeneously frozen water, Fhet(aw), to decrease by up to 40 % with increasing solute concentrations. In combination, unaltered Thet(aw) and reduced Fhet(aw) suggest that active sites were largely deactivated by the acid molecules, but amongst those remaining active are also the best sites with the highest Thet. A deviation from this behavior is citric acid, which showed not only a de-crease in Fhet, but also a decrease in Thet of up to 4 K for water activities below 0.99, pointing to a depletion of the best active sites by interactions with the citrate ions. When neutralized solutions of the acids were used instead, the de-crease in Fhet became even more pronounced. The slope of Thet(aw) was different for each of the neutralized acid solu-tions. In the case of amino acid solutions, we found a decrease in Thet (up to 10 K), significantly below the Δaw-criterion, as well as a reduction in Fhet (up to 60 %). Finally, in case of the investigated polyols, no significant devia-tion of Thet from the Δaw-criterion was observed, and no significant deviation of Fhet in comparison to a pure water suspension was found. Furthermore, we measured the effects of aging on the ice nucleation activity in experiments with microcline suspended in solutions for up to seven days, and tested the reversibility of the interaction with the solutes after aging for 10 days. For citric acid, an ongoing irreversible degradation of the ice nucleation activity was observed, whereas the amino acids showed completely reversible effects. In summary, our experiments demonstrate a remarkable sensitivity of microcline ice nucleation activity to surface interactions with various solutes, underscoring the importance of the history of such particles from source to frozen cloud droplet in the atmosphere.

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