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1.
Microb Ecol ; 87(1): 69, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38730059

RESUMO

Biocrust inoculation and microbially induced carbonate precipitation (MICP) are tools used in restoring degraded arid lands. It remains unclear whether the ecological functions of the two tools persist when these methods are combined and subjected to freeze-thaw (FT) cycles. We hypothesized a synergetic interaction between MICP treatment and biocrust under FT cycles, which would allow both components to retain their ecological functions. We grew cyanobacterial (Nostoc commune) biocrusts on bare soil and on MICP (Sporosarcina pasteurii)-treated soil, subjecting them to repeated FT cycles simulating the Mongolian climate. Generalized linear modeling revealed that FT cycling did not affect physical structure or related functions but could increase the productivity and reduce the nutrient condition of the crust. The results confirm the high tolerance of MICP-treated soil and biocrust to FT cycling. MICP treatment + biocrust maintained higher total carbohydrate content under FT stress. Our study indicates that biocrust on biomineralized soil has a robust enough structure to endure FT cycling during spring and autumn and to promote restoration of degraded lands.


Assuntos
Cianobactérias , Congelamento , Microbiologia do Solo , Solo , Solo/química , Cianobactérias/metabolismo , Cianobactérias/química , Carbonatos/química , Carbonatos/metabolismo , Ecossistema , Sporosarcina/metabolismo , Sporosarcina/crescimento & desenvolvimento
2.
Arch Microbiol ; 206(6): 258, 2024 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-38735006

RESUMO

Phycocyanin, a blue-coloured pigment, predominantly found and derived from Spirulina sp., has gained researchers' interest due to its vibrant hues and other attractive properties like antioxidant and anti-microbial. However, the lack of reliable and sustainable phycocyanin extraction strategies without compromising the quality has hindered the scaling up of its production processes for commercial purposes. Here in this study, phycocyanin was extracted from wet and dry biomass Spirulina sp., using three different physical cell disruption methods (ultrasonication, homogenization, and freeze-thaw cycles) combined with two different buffers (phosphate buffer and acetate buffer) and water (as control). The result showed that the freeze-thaw method combined with acetate buffer produced the highest yield (25.013 ± 2.572 mg/100 mg) with a purity ratio of 0.806 ± 0.079. Furthermore, when subjected to 30% w/v salt stress, 1.9 times higher phycocyanin yield with a purity ratio of 1.402 ± 0.609 was achieved using the previously optimized extraction method.


Assuntos
Ficocianina , Estresse Salino , Spirulina , Ficocianina/metabolismo , Ficocianina/isolamento & purificação , Spirulina/metabolismo , Spirulina/química , Biomassa , Congelamento
3.
PLoS One ; 19(5): e0303327, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38739645

RESUMO

This study applied the pull-out test to examine the influence of freeze-thaw cycles and hybrid fiber incorporation on the bond performance between BFRP bars and hybrid fiber-reinforced concrete. The bond-slip curves were fitted by the existing bond-slip constitutive model, and then the bond strength was predicted by a BP neural network. The results indicated that the failure mode changed from pull-out to splitting for the BFRP bar ordinary concrete specimens when the freeze-thaw cycles exceeded 50, while only pull-out failure occurred for all BFRP bar hybrid fiber-reinforced concrete specimens. An increasing trend was shown on the peak slip, but a decreasing trend was shown on the bond stiffness and bond strength when freeze-thaw cycles increased. The bond strength could be increased significantly by the incorporation of basalt fiber (BF) and cellulose fiber (CF) under the same freezing and thawing conditions as compared to concrete specimens without fibers. The Malvar model and the Continuous Curve model performed best in fitting the ascending and descending sections of the bond-slip curves, respectively. The BP neural network also accurately predicted the bond strength, with relative errors of predicted bond strengths ranging from 3.75% to 13.7%, and 86% of them being less than 10%.


Assuntos
Materiais de Construção , Congelamento , Materiais de Construção/análise , Teste de Materiais , Redes Neurais de Computação , Estresse Mecânico
4.
Med Sci Monit ; 30: e942946, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38698627

RESUMO

BACKGROUND Cryopreservation preserves male fertility, crucial in oncology, advanced age, and infertility. However, it damages sperm motility, membrane, and DNA. Zinc (Zn), an antioxidant, shows promise in improving sperm quality after thawing, highlighting its potential as a cryoprotectant in reproductive medicine. MATERIAL AND METHODS Gradient concentration of ZnSO4 (0, 12.5, 25, 50, and 100 µM) was added in the Glycerol-egg yolk-citrate (GEYC) cryopreservative medium as an extender. Alterations in sperm viability and motility parameters after cryopreservation were detected in each group. Sperm plasma membrane integrity (PMI), acrosome integrity (ACR), DNA fragment index (DFI), and changes in sperm mitochondrial function were examined, including: mitochondrial potential (MMP), sperm reactive oxygen species (ROS), and sperm ATP. RESULTS We found that 50 µM ZnSO4 was the most effective for the curvilinear velocity (VCL) and the average path velocity (VAP) of sperm after cryo-resuscitation. Compared to the Zn-free group, sperm plasma membrane integrity (PMI) was increased, DNA fragmentation index (DFI) was decreased, reactive oxygen species (ROS) was reduced, and mitochondrial membrane potential (MMP) was increased after cryorevival in the presence of 50 µM ZnSO4. CONCLUSIONS Zn ion is one of the antioxidants in the cell. The results of our current clinical study are sufficient to demonstrate that Zn can improve preserves sperm quality during cryopreservation when added to GEYC. The addition of 50 µM ZnSO4 increased curve velocity, mean path velocity, sperm survival (or plasma membrane integrity), and mitochondrial membrane potential while reducing ROS production and DNA breaks compared to GEYC thawed without ZnSO4.


Assuntos
Criopreservação , Crioprotetores , Fragmentação do DNA , Potencial da Membrana Mitocondrial , Espécies Reativas de Oxigênio , Preservação do Sêmen , Motilidade dos Espermatozoides , Espermatozoides , Zinco , Masculino , Criopreservação/métodos , Humanos , Espermatozoides/efeitos dos fármacos , Espermatozoides/metabolismo , Crioprotetores/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Motilidade dos Espermatozoides/efeitos dos fármacos , Preservação do Sêmen/métodos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Fragmentação do DNA/efeitos dos fármacos , Zinco/farmacologia , Zinco/metabolismo , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Análise do Sêmen , Sobrevivência Celular/efeitos dos fármacos , Adulto , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Acrossomo/efeitos dos fármacos , Acrossomo/metabolismo , Congelamento
5.
Cryo Letters ; 45(3): 185-193, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38709190

RESUMO

BACKGROUND: Characterization of intracellular ice formation (IIF) in oocytes during the freezing and thawing processes will contribute to optimizing their cryopreservation. However, the observation of the ice formation process in oocytes is limited by the spatiotemporal resolution of the cryomicroscope systems. OBJECTIVE: To observe the intracellular icing of oocytes during cooling and rewarming, and to study the mechanism of formation and growth of intracellular ice in oocytes. MATERIALS AND METHODS: Mouse oocytes were frozen at different cooling rates to induce intracellular ice formation using a cryomicroscopy system consisting of a microscope equipped with a cryogenic cold stage, an automatic cooling system, a temperature control system, and a high-speed camera. The growth patterns of intracellular ice in oocytes were analyzed from the images recorded. Finally, the growth rate of intracellular ice formation in oocytes was calculated using an automatic intracellular ice tracking method. RESULTS: The IIF temperature decreased gradually with the increase in cooling rate. Initiation sites of IIF could be classified into three categories: marginal type, internal type and coexisting type. There was a strong predominance for ice crystal initiation site in the oocytes, with up to 80% of the initiation sites located in the marginal region. The intracellular ice growth modes of darkening and twitching cells were characterized by "spreading" and "clustering", respectively. In addition, twitching cells started to recrystallize during rewarming, while darkening cells did not. The instantaneous maximal growth rate of ice crystals in twitching cells was about 10 times higher than that in darkening cells. CONCLUSION: By visualising the growth of ice crystals in mouse oocytes during cooling and rewarming, we obtained valuable information on the kinetics of ice formation and melting in these cells. This information can help us understand how ice formation and melting affect the viability and quality of oocytes after cryopreservation. Doi.org/10.54680/fr24310110412.


Assuntos
Criopreservação , Gelo , Oócitos , Animais , Camundongos , Oócitos/citologia , Oócitos/fisiologia , Criopreservação/métodos , Feminino , Congelamento , Cristalização , Microscopia/métodos
6.
AAPS PharmSciTech ; 25(5): 102, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38714592

RESUMO

Freezing of biological drug substance (DS) is a critical unit operation that may impact product quality, potentially leading to protein aggregation and sub-visible particle formation. Cryo-concentration has been identified as a critical parameter to impact protein stability during freezing and should therefore be minimized. The macroscopic cryo-concentration, in the following only referred to as cryo-concentration, is majorly influenced by the freezing rate, which is in turn impacted by product independent process parameters such as the DS container, its size and fill level, and the freezing equipment. (At-scale) process characterization studies are crucial to understand and optimize freezing processes. However, evaluating cryo-concentration requires sampling of the frozen bulk, which is typically performed by cutting the ice block into pieces for subsequent analysis. Also, the large amount of product requirement for these studies is a major limitation. In this study, we report the development of a simple methodology for experimental characterization of frozen DS in bottles at relevant scale using a surrogate solution. The novel ice core sampling technique identifies the axial ice core in the center to be indicative for cryo-concentration, which was measured by osmolality, and concentrations of histidine and polysorbate 80 (PS80), whereas osmolality revealed to be a sensitive read-out. Finally, we exemplify the suitability of the method to study cryo-concentration in DS bottles by comparing cryo-concentrations from different freezing protocols (-80°C vs -40°C). Prolonged stress times during freezing correlated to a higher extent of cryo-concentration quantified by osmolality in the axial center of a 2 L DS bottle.


Assuntos
Embalagem de Medicamentos , Congelamento , Gelo , Embalagem de Medicamentos/métodos , Concentração Osmolar , Polissorbatos/química , Histidina/química , Produtos Biológicos/química
7.
Int J Mol Sci ; 25(9)2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38732084

RESUMO

Bacteriophage fitness is determined by factors influencing both their replication within bacteria and their ability to maintain infectivity between infections. The latter becomes particularly crucial under adverse environmental conditions or when host density is low. In such scenarios, the damage experienced by viral particles could lead to the loss of infectivity, which might be mitigated if the virus undergoes evolutionary optimization through replication. In this study, we conducted an evolution experiment involving bacteriophage Qß, wherein it underwent 30 serial transfers, each involving a cycle of freezing and thawing followed by replication of the surviving viruses. Our findings show that Qß was capable of enhancing its resistance to this selective pressure through various adaptive pathways that did not impair the virus replicative capacity. Notably, these adaptations predominantly involved mutations located within genes encoding capsid proteins. The adapted populations exhibited higher resistance levels than individual viruses isolated from them, and the latter surpassed those observed in single mutants generated via site-directed mutagenesis. This suggests potential interactions among mutants and mutations. In conclusion, our study highlights the significant role of extracellular selective pressures in driving the evolution of phages, influencing both the genetic composition of their populations and their phenotypic properties.


Assuntos
Congelamento , Mutação , Fagos RNA/genética , Fagos RNA/fisiologia , Adaptação Fisiológica/genética , Evolução Molecular , Replicação Viral/genética , Proteínas do Capsídeo/genética
8.
Plant Physiol Biochem ; 210: 108621, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38604012

RESUMO

To enhance the postharvest quality of avocado (Persea americana Mill.) fruit, this study investigates alterations in cell wall metabolism and reactive oxygen species (ROS) metabolism during near-freezing temperature (NFT) storage, and explores their impact on fruit softening. The fruit was stored at 25 °C, 5 °C, 2 °C, and NFT, respectively. NFT storage retarded firmness loss and chilling injury in comparison with 25 °C, 5 °C, and 2 °C. NFT storage delayed the decrease of ionic-soluble pectin (ISP) and cellulose (CLL) contents by suppressing cell wall degradation enzyme activities. Correlation analysis showed that cell wall degradation enzyme activities were positively correlated to rates of ethylene release and respiration. Moreover, NFT storage maintained higher levels of DPPH and ABTS scavenging abilities, activities of superoxide dismutase, peroxidase, and catalase, as well as ascorbate-glutathione cycle (ascorbic acid, glutathione, glutathione disulfide, ascorbate peroxidase, cycle-related enzymes), thereby inhibited the increase of ROS content, malondialdehyde content, and cell membrane permeability. Fruit firmness and chilling injury were correlated with the contents of hydrogen (H2O2), superoxide anion (O2.-), ISP, and CLL. These results suggested that NFT could suppress fruit softening and chilling injury by inhibiting cell wall degradation through delaying respiration and ethylene production and suppressing ROS production via activation of antioxidant systems, thereby maintaining quality and prolonged storage life during avocado fruit storage.


Assuntos
Parede Celular , Frutas , Persea , Espécies Reativas de Oxigênio , Persea/metabolismo , Parede Celular/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Frutas/metabolismo , Armazenamento de Alimentos/métodos , Temperatura Baixa , Congelamento , Etilenos/metabolismo , Pectinas/metabolismo , Celulose/metabolismo
9.
Plant Physiol Biochem ; 210: 108576, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38608502

RESUMO

Low temperature severely affects the geographical distribution and production of potato, which may incur cold damage in early spring or winter. Cultivated potatoes, mainly derived from Solanum tuberosum, are sensitive to freezing stress, but wild species of potato such as S. commersonii exhibit both constitutive freezing tolerance and/or cold acclimation tolerance. Hence, such wild species could assist in cold hardiness breeding. Yet the key transcription factors and their downstream functional genes that confer freezing tolerance are far from clear, hindering the breeding process. Here, we used ATAC-seq (Assay for Transposase-Accessible Chromatin with high-throughput sequencing) alongside RNA-seq to investigate the variation in chromatin accessibility and patterns of gene expression in freezing-tolerant CMM5 (S. commersonii), before and after its cold treatment. Our results suggest that after exposure to cold, transcription factors including Dof3, ABF2, PIF4, and MYB4 were predicted to further control the genes active in the synthetic/metabolic pathways of plant hormones, namely abscisic acid, polyamine, and reductive glutathione (among others). This suggests these transcription factors could regulate freezing tolerance of CMM5 leaves. In particular, ScDof3 was proven to regulate the expression of ScproC (pyrroline-5-carboxylate reductase, P5CR) according to dual-LUC assays. Overexpressing ScDof3 in Nicotiana benthamiana leaves led to an increase in both the proline content and expression level of NbproC (homolog of ScproC). These results demonstrate the ScDof3-ScproC module regulates the proline content and thus promotes freezing tolerance in potato. Our research provides valuable genetic resources to further study the molecular mechanisms underpinning cold tolerance in potato.


Assuntos
Aclimatação , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas , Solanum tuberosum , Solanum tuberosum/genética , Solanum tuberosum/metabolismo , Solanum tuberosum/fisiologia , Aclimatação/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Transcriptoma/genética , Temperatura Baixa , Congelamento , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
10.
Int J Biol Macromol ; 267(Pt 1): 131418, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38582465

RESUMO

In this work, the effects of low-frequency alternating magnetic fields (LF-AMF) on the physicochemical, conformational, and functional characteristics of myofibrillar protein (MP) after iterative freeze-thaw (FT) cycles were explored. With the increasing LF-AMF treatment time, the solubility, active sulfhydryl groups, surface hydrophobicity, emulsifiability, and emulsion stability of MP after five FT cycles evidently elevated and then declined, and the peak value was obtained at 3 h. Conversely, the moderate LF-AMF treatment time can significantly reduce the average particle size, carbonyl content, and endogenous fluorescence intensity of MP. The rheology results showed that various LF-AMF treatment times would elevate the G' value of MP after iterative FT cycles. The FTIR spectroscopy results suggested that LF-AMF influenced the secondary structure of MP after multiple FT cycles, resulting in a depression in α-helix content and an increment in ß-folding proportion. Moreover, LF-AMF treatment induced the gradually lighter and wider myosin heavy chain bands of MP, implying that LF-AMF accelerated the degradation of macromolecular aggregates. Therefore, the LF-AMF treatment efficaciously ameliorates the structural and functional deterioration of MP after iterative FT cycles and could be used as a potential quality-improving technology in the frozen meat industry.


Assuntos
Congelamento , Campos Magnéticos , Proteínas Musculares , Reologia , Proteínas Musculares/química , Miofibrilas/química , Solubilidade , Animais , Fenômenos Químicos , Conformação Proteica , Interações Hidrofóbicas e Hidrofílicas
12.
J Hazard Mater ; 470: 134249, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38603909

RESUMO

In cold regions, microplastics (MPs) in the soil undergo freeze-thaw (FT) aging process. Little is known about how FT aged MPs influence soil physico-chemical properties and microbial communities. Here, two environmentally relevant concentrations (50 and 500 mg/kg) of 50 and 500 µm polyethylene (PE) and polypropylene (PP) MPs treated soils were subjected to 45-day FT cycles (FTCs). Results showed that MPs experienced surface morphology, hydrophobicity and crystallinity alterations after FTCs. After 45-day FTCs, the soil urease (SUE) activity in control (MPs-free group that underwent FTCs) was 33.49 U/g. SUE activity in 50 µm PE group was reduced by 19.66 %, while increased by 21.16 % and 37.73 % in 500 µm PE and PP groups compared to control. The highest Shannon index was found in 50 µm PP-MPs group at 50 mg/kg, 2.26 % higher than control (7.09). Compared to control (average weighted degree=8.024), all aged MPs increased the complexity of network (0.19-1.43 %). Bacterial biomarkers of aged PP-MPs were associated with pollutant degradation. Aged PP-MPs affected genetic information, cellular processes, and disrupted the biosynthesis of metabolites. This study provides new insights into the potential hazards of MPs after FTCs on soil ecosystem in cold regions.


Assuntos
Microplásticos , Polietileno , Polipropilenos , Microbiologia do Solo , Poluentes do Solo , Urease , Polietileno/toxicidade , Microplásticos/toxicidade , Poluentes do Solo/toxicidade , Urease/metabolismo , Congelamento , Microbiota/efeitos dos fármacos , Bactérias/efeitos dos fármacos , Bactérias/genética , Solo/química
13.
Cryo Letters ; 45(2): 100-105, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38557988

RESUMO

BACKGROUND: Nanotechnology can benefit livestock industries, especially through postharvest semen manipulation. Zinc oxide nanoparticles (Np-ZnO) are potentially an example. OBJECTIVE: To investigate how the addition of zinc oxide nanoparticles (Np-ZnO) affected the characteristics of post-thawed goat semen. MATERIALS AND METHODS: Seminal pools from four Saanen bucks were used. Semen was diluted in Tris-egg yolk extender, supplemented with Np-ZnO (0, 50, 100 or 200 ug/mL), frozen and stored in liquid nitrogen (-196 degree C), and thawed in a water bath (37 degree C / 30 s). Semen samples were evaluated for sperm kinetics by computer-assisted sperm analysis (CASA), and assessed for other functional properties by epifluorescence microscopy, such as plasma membrane integrity (PMi), acrosomal membrane integrity (ACi) and mitochondrial membrane potential (MMP). RESULTS: For total motility (TM), the group treated with 200 ug/mL Np-ZnO was superior to the control. In straight-line velocity (VSL), the control was better than the group containing 200 ug/mL of Np-ZnO. For average path velocity (VAP), the control was higher than with 100 ug/mL Np-ZnO. For linearity (LIN), the control was higher than with 200 µg/mL Np-ZnO. In straightness (STR), the control and 100 µg/mL Np-ZnO were higher than with 200 ug/mL Np-ZnO. In wobble (WOB), the control was better than the 50 µg/mL Np-ZnO treatment. In PMi, ACi and MMP no significant differences were found. CONCLUSION: The addition of Np-ZnO (200 ug/mL) to the goat semen freezing extender improved the total motility of cells, whilst negatively affecting sperm kinetics. https://doi.org/10.54680/fr24210110512.


Assuntos
Preservação do Sêmen , Óxido de Zinco , Animais , Masculino , Congelamento , Sêmen , Óxido de Zinco/farmacologia , Cabras , Crioprotetores/farmacologia , Criopreservação/veterinária , Motilidade dos Espermatozoides , Preservação do Sêmen/veterinária , Espermatozoides
14.
Int J Mol Sci ; 25(8)2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38673743

RESUMO

Semen cryopreservation has played an important role in medically assisted reproduction for decades. In addition to preserving male fertility, it is sometimes used for overcoming logistical issues. Despite its proven clinical usability and safety, there is a lack of knowledge of how it affects spermatozoa at the molecular level, especially in terms of non-coding RNAs. Therefore, we conducted this study, where we compared slow freezing and vitrification of good- and poor-quality human semen samples by analyzing conventional sperm quality parameters, performing functional tests and analyzing the expression of miRNAs. The results revealed that cryopreservation of normozoospermic samples does not alter the maturity of spermatozoa (protamine staining, hyaluronan binding), although cryopreservation can increase sperm DNA fragmentation and lower motility. On a molecular level, we revealed that in both types of cryopreservation, miRNAs from spermatozoa are significantly overexpressed compared to those in the native semen of normozoospermic patients, but in oligozoospermic samples, this effect is observed only after vitrification. Moreover, we show that expression of selected miRNAs is mostly overexpressed in native oligozoospermic samples compared to normozoospermic samples. Conversely, when vitrified normozoospermic and oligozoospermic samples were compared, we determined that only miR-99b-5p was significantly overexpressed in oligozoospermic sperm samples, and when comparing slow freezing, only miR-15b-5p and miR-34b-3p were significantly under-expressed in oligozoospermic sperm samples. Therefore, our results imply that cryopreservation of normozoospermic sperm samples can modulate miRNA expression profiles in spermatozoa to become comparable to those in oligozoospermic samples.


Assuntos
Criopreservação , MicroRNAs , Análise do Sêmen , Preservação do Sêmen , Sêmen , Espermatozoides , Vitrificação , Humanos , MicroRNAs/genética , Masculino , Criopreservação/métodos , Análise do Sêmen/métodos , Preservação do Sêmen/métodos , Sêmen/metabolismo , Espermatozoides/metabolismo , Motilidade dos Espermatozoides/genética , Congelamento , Adulto , Fragmentação do DNA
15.
Physiol Plant ; 176(3): e14292, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38685817

RESUMO

Tracer injection has long been recognized as a valuable tool for delineating tree hydraulics and assessing water transport pathways. Recently, isotope tracers have emerged as innovative instruments for investigating tree hydraulics, providing new insights into tree water dynamics. Nevertheless, there is a critical need for further research to comprehensively grasp water movement and distribution within trees. A previously introduced technique for analyzing the isotopic ratio of water in wet tissues, offering millimeter-scale resolution for visualizing tracer movement, faces challenges due to its underdeveloped sample preparation techniques. In this study, we introduced an H2 18O tracer into S. gracilistyla samples, exclusively comprising indeterminate roots, stems, and leaves, cultivated through hydroponics and grown within the current year. Our objective was to assess the axial distribution of the tracer in the xylem. Additionally, we devised a novel method for preparing frozen wet tissue samples, enhancing the repeatability and success rate of experiments. The results demonstrated that all frozen wet tissue samples exhibited an average water loss rate of less than 0.6%. Isotopic analysis of these samples unveiled a consistent decline in tracer concentration with increasing height in all Salix specimens, with three out of five samples revealing a significant isotope gradient. Our findings affirm the efficacy and practicality of combining isotopic labeling with freezing, stabilization, and preparation techniques. Looking ahead, our isotopic labeling and analysis methods are poised to transcend woody plants, finding extensive applications in plant physiology and ecohydrology.


Assuntos
Congelamento , Isótopos de Oxigênio , Árvores , Água , Xilema , Isótopos de Oxigênio/análise , Água/metabolismo , Árvores/metabolismo , Xilema/metabolismo , Xilema/química , Folhas de Planta/metabolismo , Folhas de Planta/química , Raízes de Plantas/metabolismo , Raízes de Plantas/química , Marcação por Isótopo/métodos , Caules de Planta/química , Caules de Planta/metabolismo
16.
Funct Plant Biol ; 512024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38669459

RESUMO

Mitogen-activated protein kinases (MAPKs) play important roles in plant stress response. As a major member of the MAPK family, MPK3 has been reported to participate in the regulation of chilling stress. However, the regulatory function of wheat (Triticum aestivum ) mitogen-activated protein kinase TaMPK3 in freezing tolerance remains unknown. Dongnongdongmai No.1 (Dn1) is a winter wheat variety with strong freezing tolerance; therefore, it is important to explore the mechanisms underlying this tolerance. In this study, the expression of TaMPK3 in Dn1 was detected under low temperature and hormone treatment. Gene cloning, bioinformatics and subcellular localisation analyses of TaMPK3 in Dn1 were performed. Overexpressed TaMPK3 in Arabidopsis thaliana was obtained, and freezing tolerance phenotype observations, physiological indices and expression levels of ICE-C-repeat binding factor (CBF)-COR -related genes were determined. In addition, the interaction between TaMPK3 and TaICE41 proteins was detected. We found that TaMPK3 expression responds to low temperatures and hormones, and the TaMPK3 protein is localised in the cytoplasm and nucleus. Overexpression of TaMPK3 in Arabidopsis significantly improves freezing tolerance. TaMPK3 interacts with the TaICE41 protein. In conclusion, TaMPK3 is involved in regulating the ICE-CBF-COR cold resistance module through its interaction with TaICE41, thereby improving freezing tolerance in Dn1 wheat.


Assuntos
Arabidopsis , Congelamento , Regulação da Expressão Gênica de Plantas , Triticum , Arabidopsis/genética , Triticum/genética , Triticum/metabolismo , Triticum/enzimologia , Plantas Geneticamente Modificadas/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas Quinases Ativadas por Mitógeno/genética
17.
Nano Lett ; 24(17): 5351-5360, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38634773

RESUMO

Ultrasensitive and reliable conductive hydrogels are significant in the construction of human-machine twinning systems. However, in extremely cold environments, freezing severely limits the application of hydrogel-based sensors. Herein, building on biomimetics, a zwitterionic hydrogel was elaborated for human-machine interaction employing multichemical bonding synergies and experimental signal analyses. The covalent bonds, hydrogen bonds, and electrostatic interactions construct a dense double network structure favorable for stress dispersion and hydrogen bond regeneration. In particular, zwitterions and ionic conductors maintained excellent strain response (99 ms) and electrical sensitivity (gauge factor = 14.52) in the dense hydrogel structure while immobilizing water molecules to enhance the weather resistance (-68 °C). Inspired by the high sensitivity, zwitterionic hydrogel-based strain sensors and remote-control gloves were designed by analyzing the experimental signals, demonstrating promising potential applications within specialized flexible materials and human-machine symbiotic systems.


Assuntos
Hidrogéis , Hidrogéis/química , Humanos , Dispositivos Eletrônicos Vestíveis , Congelamento , Ligação de Hidrogênio , Eletricidade Estática , Condutividade Elétrica
18.
Protein Sci ; 33(5): e4989, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38659213

RESUMO

Intrinsically disordered late embryogenesis abundant (LEA) proteins play a central role in the tolerance of plants and other organisms to dehydration brought upon, for example, by freezing temperatures, high salt concentration, drought or desiccation, and many LEA proteins have been found to stabilize dehydration-sensitive cellular structures. Their conformational ensembles are highly sensitive to the environment, allowing them to undergo conformational changes and adopt ordered secondary and quaternary structures and to participate in formation of membraneless organelles. In an interdisciplinary approach, we discovered how the functional diversity of the Arabidopsis thaliana LEA protein COR15A found in vitro is encoded in its structural repertoire, with the stabilization of membranes being achieved at the level of secondary structure and the stabilization of enzymes accomplished by the formation of oligomeric complexes. We provide molecular details on intra- and inter-monomeric helix-helix interactions, demonstrate how oligomerization is driven by an α-helical molecular recognition feature (α-MoRF) and provide a rationale that the formation of noncanonical, loosely packed, right-handed coiled-coils might be a recurring theme for homo- and hetero-oligomerization of LEA proteins.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Proteínas Intrinsicamente Desordenadas , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Arabidopsis/química , Arabidopsis/metabolismo , Proteínas Intrinsicamente Desordenadas/química , Proteínas Intrinsicamente Desordenadas/metabolismo , Proteínas Intrinsicamente Desordenadas/genética , Congelamento , Modelos Moleculares , Multimerização Proteica , Estrutura Secundária de Proteína
19.
PLoS One ; 19(4): e0302409, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38662726

RESUMO

Natural disasters such as landslides often occur on soil slopes in seasonally frozen areas that undergo freeze‒thaw cycling. Ecological slope protection is an effective way to prevent such disasters. To explore the change in the mechanical properties of soil under the influence of both root reinforcement and freeze‒thaw cycles and its influence on slope stability, the Baijiabao landslide in the Three Gorges Reservoir area was taken as an example. The mechanical properties of soil under different confining pressures, vegetation coverages (VCs) and numbers of freeze‒thaw cycles were studied via mechanical tests, such as triaxial compression tests, wave velocity tests and FLAC3D simulations. The results show that the shear strength of a root-soil composite increases with increasing confining pressure and VC and decreases with increasing number of freeze‒thaw cycles. Bermuda grass roots and confining pressure jointly improve the durability of soil under freeze‒thaw conditions. However, with an increase in the number of freeze‒thaw cycles, the resistance of root reinforcement to freeze‒thaw action gradually decreases. The observed effect of freeze‒thaw cycles on soil degradation was divided into three stages: a significant decrease in strength, a slight decrease in strength and strength stability. Freeze‒thaw cycles and VC mainly affect the cohesion of the soil and have little effect on the internal friction angle. Compared with that of a bare soil slope, the safety factor of a slope covered with plants is larger, the maximum displacement of a landslide is smaller, and it is less affected by freezing and thawing. These findings can provide a reference for research on ecological slope protection technology.


Assuntos
Congelamento , Raízes de Plantas , Solo , Solo/química , Raízes de Plantas/fisiologia , Deslizamentos de Terra
20.
Food Res Int ; 184: 114265, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38609243

RESUMO

Radio frequency explosion puffing (RFEP) is a novel oil-free puffing technique used to produce crispy textured and nutritious puffed snacks. This study aimed to investigate the effects of freezing at different temperatures (-20 °C, -40 °C, -80 °C) for14 h and freezing times (1 and 2 times) on the cellular structure of purple sweet potato and the quality of RFEP chips. The analysis of cell microstructure, conductivity, and rheology revealed that higher freezing temperatures and more freezing times resulted in increased damage to the cellular structure, leading to greater cell membrane permeability and decreased cell wall stiffness. However, excessive damage to cellular structure caused tissue structure to collapse. Compared with the control group (4 °C), the RFEP sample pre-frozen once at -40 °C had a 47.13 % increase in puffing ratio and a 61.93 % increase in crispness, while hardness decreased by 23.44 % (p < 0.05). There was no significant change in anthocyanin retention or color difference. X-ray microtomography demonstrated that the RFEP sample pre-frozen once at -40 °C exhibited a more homogeneous morphology and uniform pore distribution, resulting in the highest overall acceptability. In conclusion, freezing pre-treatment before RFEP can significantly enhance the puffing quality, making this an effective method for preparing oil-free puffing products for fruits and vegetables.


Assuntos
Ipomoea batatas , Congelamento , Explosões , Parede Celular , Temperatura Baixa
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