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1.
Front Aging Neurosci ; 16: 1431280, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39006221

RESUMO

Introduction: Freezing of gait (FOG) is a paroxysmal motor phenomenon that increases in prevalence as Parkinson's disease (PD) progresses. It is associated with a reduced quality of life and an increased risk of falls in this population. Precision-based detection and classification of freezers are critical to developing tailored treatments rooted in kinematic assessments. Methods: This study analyzed instrumented stand-and-walk (SAW) trials from advanced PD patients with STN-DBS. Each patient performed two SAW trials in their OFF Medication-OFF DBS state. For each trial, gait summary statistics from wearable sensors were analyzed by machine learning classification algorithms. These algorithms include k-nearest neighbors, logistic regression, naïve Bayes, random forest, and support vector machines (SVM). Each of these models were selected for their high interpretability. Each algorithm was tasked with classifying patients whose SAW trials MDS-UPDRS FOG subscore was non-zero as assessed by a trained movement disorder specialist. These algorithms' performance was evaluated using stratified five-fold cross-validation. Results: A total of 21 PD subjects were evaluated (average age 64.24 years, 16 males, mean disease duration of 14 years). Fourteen subjects had freezing of gait in the OFF MED/OFF DBS. All machine learning models achieved statistically similar predictive performance (p < 0.05) with high accuracy. Analysis of random forests' feature estimation revealed the top-ten spatiotemporal predictive features utilized in the model: foot strike angle, coronal range of motion [trunk and lumbar], stride length, gait speed, lateral step variability, and toe-off angle. Conclusion: These results indicate that machine learning effectively classifies advanced PD patients as freezers or nonfreezers based on SAW trials in their non-medicated/non-stimulated condition. The machine learning models, specifically random forests, not only rely on but utilize salient spatial and temporal gait features for FOG classification.

2.
Foods ; 13(13)2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38998623

RESUMO

Freezing affects texture and induces the loss of gel quality. This study investigated the effects of methylcellulose (MC) (0.2%, 0.4%, 0.6%) and sodium hexametaphosphate (SHMP) (0.15%, 0.3%) on the gel textural and structural properties of SPI gels before and after freezing, and explores the synergistic enhancement of gel texture and the underlying mechanisms resulting from the simultaneous addition of SHMP and MC to SPI gels. It was revealed that MC improved the strength of SPI gels through its thickening properties, but it could not inhibit the reduction of SPI gels after freezing. The 0.4% MC-SPI gel exhibited the best gel strength (193.2 ± 2.4 g). SHMP inhibited gel reduction during freezing through hydrogen bonding and ionic interactions; it enhanced the freezing stability of SPI gels. The addition of 0.15% SHMP made the water-holding capacity in SPI gels reach the highest score after freezing (58.2 ± 0.32%). The synergistic effect of MC and SHMP could improve the strength and the freezing stability of SPI gels. MC facilitated the release of ionizable groups within SPI, causing negatively charged SHMP groups to aggregate on the SPI and inhibit the freezing aggregation of proteins. These results provide a strong basis for the improvement of cryogenic soy protein gel performance by SHMP and MC.

3.
Artif Intell Med ; 154: 102932, 2024 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-39004005

RESUMO

Freezing of Gait (FOG) is a noticeable symptom of Parkinson's disease, like being stuck in place and increasing the risk of falls. The wearable multi-channel sensor system is an efficient method to predict and monitor the FOG, thus warning the wearer to avoid falls and improving the quality of life. However, the existing approaches for the prediction of FOG mainly focus on a single sensor system and cannot handle the interference between multi-channel wearable sensors. Hence, we propose a novel multi-channel time-series neural network (MCT-Net) approach to merge multi-channel gait features into a comprehensive prediction framework, alerting patients to FOG symptoms in advance. Owing to the causal distributed convolution, MCT-Net is a real-time method available to give optimal prediction earlier and implemented in remote devices. Moreover, intra-channel and inter-channel transformers of MCT-Net extract and integrate different sensor position features into a unified deep learning model. Compared with four other state-of-the-art FOG prediction baselines, the proposed MCT-Net obtains 96.21% in accuracy and 80.46% in F1-score on average 2 s before FOG occurrence, demonstrating the superiority of MCT-Net.

4.
J Struct Biol X ; 9: 100102, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38962493

RESUMO

Microcrystal electron diffraction (MicroED) has emerged as a powerful technique for unraveling molecular structures from microcrystals too small for X-ray diffraction. However, a significant hurdle arises with plate-like crystals that consistently orient themselves flat on the electron microscopy grid. If the normal of the plate correlates with the axes of the crystal lattice, the crystal orientations accessible for measurement are restricted because the crystal cannot be arbitrarily rotated. This limits the information that can be acquired, resulting in a missing cone of information. We recently introduced a novel crystallization strategy called suspended drop crystallization and proposed that crystals in a suspended drop could effectively address the challenge of preferred crystal orientation. Here we demonstrate the success of the suspended drop approach in eliminating the missing cone in two samples that crystallize as thin plates: bovine liver catalase and the SARS­CoV­2 main protease (Mpro). This innovative solution proves indispensable for crystals exhibiting systematic preferred orientations, unlocking new possibilities for structure determination by MicroED.

5.
Food Chem ; 457: 140089, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38955122

RESUMO

Ice fractions and water states in partially frozen muscle foods greatly affect their quality. In the study, a variable temperature nuclear magnetic resonance (VT-NMR) with a liquid nitrogen temperature control system was employed to in situ investigate the relationship between ice fractions and temperatures and changes in water states during partial freezing and thawing of pork and shrimp. Results indicated that changes in ice fractions ranging from -2 âˆ¼ -20 °C could be divided into 3 stages including slow increase, random leap and remarkable leap. More serious damages to the structures related to immobile water occurred in shrimp than in pork, and partial freezing also caused deterioration in muscle fibres related to free water. Additionally, -2 âˆ¼ -3 °C and - 3.5 °C were the appropriate partial freezing temperatures for pork and shrimp, respectively. Therefore, the VT-NMR method possessed great potential for fundamental studies and applications of partial freezing of muscle foods.

6.
AAPS J ; 26(4): 76, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38955873

RESUMO

The selection of skin is crucial for the in vitro permeation test (IVPT). The purpose of this study was to investigate the influence of different freezing-thawing processes on the barrier function of skin and the transdermal permeability of granisetron and lidocaine. Rat and hairless mouse skins were thawed at three different conditions after being frozen at -20℃ for 9 days: thawed at 4℃, room temperature (RT), and 32℃. There were no significant differences in the steady-state fluxes of drugs between fresh and thawed samples, but compared with fresh skin there were significant differences in lag time for the permeation of granisetron in rat skins thawed at RT and 32℃. Histological research and scanning electron microscopy images showed no obvious structural damage on frozen/thawed skin, while immunohistochemical staining and enzyme-linked immunosorbent assay for the tight junction (TJ) protein Cldn-1 showed significantly impaired epidermal barrier. It was concluded that the freezing-thawing process increases the diffusion rate of hydrophilic drugs partly due to the functional degradation of TJs. It's recommended that hairless, inbred strains and identical animal donors should be used, and the selected thawing method of skin should be validated prior to IVPT, especially for hydrophilic drugs.


Assuntos
Congelamento , Camundongos Pelados , Permeabilidade , Absorção Cutânea , Pele , Animais , Pele/metabolismo , Camundongos , Absorção Cutânea/efeitos dos fármacos , Ratos , Masculino , Administração Cutânea , Lidocaína/administração & dosagem , Lidocaína/farmacocinética , Ratos Sprague-Dawley
7.
Artigo em Inglês | MEDLINE | ID: mdl-38955888

RESUMO

PURPOSE: To examine the effects of age, mature oocyte number, and cycle number on cumulative live birth rates after planned oocyte cryopreservation (OC), with the goal of developing a patient counselling tool. METHODS: We performed a retrospective cohort study of all patients with ≥ 1 autologous oocyte thaw at our university-affiliated fertility center before 12/31/2023. Patients were included if they (1) had a live birth or ongoing pregnancy > 12 weeks from OC, or (2) used all oocytes and euploid/untested embryos from OC. Primary outcome was cumulative live birth / ongoing pregnancy rate (CLBR). RESULTS: 527 patients with 1 OC cycle, 149 patients with 2 OC cycles, and 55 patients with ≥ 3 OC cycles were included. Overall CLBR was 43%. CLBR was > 70% among patients who thawed ≥ 20 mature oocytes that were cryopreserved at age < 38 years. Multiple logistic regression showed that age at first OC and total number of mature oocytes thawed independently predicted CLBR, but number of OC cycles did not. CONCLUSION: Patients must be counselled that younger age at OC and more mature oocytes improve CLBR. However, additional OC cycles do not independently improve CLBR. Our results can help patients decide whether to pursue additional OC cycles to obtain more oocytes.

8.
Nano Lett ; 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38976791

RESUMO

Crystalline monolayers prevalent in nature and technology possess elusive elastic properties with important implications in fundamental physics, biology, and nanotechnology. Leveraging the recently discovered shape transitions of oil-in-water emulsion droplets, upon which these droplets adopt cylindrical shapes and elongate, we investigate the elastic characteristics of the crystalline monolayers covering their interfaces. To unravel the conditions governing Euler buckling and Brazier kink formation in these cylindrical tubular interfacial crystals, we strain the elongating cylindrical droplets within confining microfluidic wells. Our experiments unveil a nonclassical relation between the Young's modulus and the bending modulus of these crystals. Intriguingly, this relation varies with the radius of the cylindrical crystal, presenting a nonclassical mechanism for tuning of elasticity in nanotechnology applications.

9.
J Plant Res ; 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38977619

RESUMO

Stem water content serves as a pivotal parameter that reflects the plant vitality and maintains their internal water balance. Given the insufficient comprehension regarding the stem water content characteristics and its influencing factors during different stages of the overwintering period, the study focused on Acer truncatum Bunge and developed an Internet of Things (IoT)-based ecological information monitoring system. The system incorporated a proprietary stem water content sensor, allowing non-invasive, in-situ and real time acquisition of stem water content while monitoring diverse environmental parameters. We conducted a detailed elucidation of stem water content variation characteristics and their responses to diverse environmental factors. The results showed: (1) During the overwintering period, stem water content exhibited diurnal variations characterized by " daytime ascent and nighttime descent" across the three stages, exhibiting differences in the moment when the stem water content reaches extremal values and daily fluctuations ranges. Stem water content exhibited minimal fluctuations during deciduous and bud-breaking stages but experienced significant freezing-thawing alternations during the dormant stage, leading to an increased daily fluctuation range. (2) The Pearson correlation coefficients between environmental parameters and stem water content varied dynamically across stages. Path analysis revealed that during the deciduous stage, stem temperature and saturation vapor pressure deficit were dominant factors influencing stem water content; during dormant stage, air temperature and saturation vapor pressure deficit directly impacted stem water content; during the bud-breaking stage, the primary parameters affecting stem water content were saturation vapor pressure deficit and stem temperature. The study provides valuable insights into unveiling the water transport patterns within tree stems tissue and their environmental adaptation mechanisms during the overwintering period, aiding in the scientific development of winter management strategies to protect trees from severe cold and freezing damage, while fostering healthy growth in the subsequent year.

10.
Food Chem ; 458: 140258, 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38959800

RESUMO

Improving the freezing resistance of yeast in dough starters is one of the most effective methods to promote the healthy development of frozen dough technology. When the dough starter was composed of yeast, lactic acid bacteria and acetic acid bacteria, the microbial proportion was 10:1:5, and the ratio of wheat flour to corn flour was 1:1. The proline contents of the starters and the survival rates and fermentation capacity of yeast significantly increased compared with those of the starter composed of yeast and wheat flour only (P < 0.05). Laser confocal microscopy observation showed that the cell membrane damage of yeast obviously decreased. Low-field nuclear magnetic resonance method revealed that the water distribution state of starters changed. Adding corn flour and acetic acid bacteria to dough starter in appropriate proportions improves yeast freezing resistance.

11.
Fertil Steril ; 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38964588

RESUMO

OBJECTIVE: To characterize the literature on social oocyte preservation, specifically the return rates, thaw rates, clinical pregnancy rates, and live birth rates. IMPORTANCE: Oocyte preservation for planned fertility delay, also referred to as social oocyte preservation or colloquially as "egg freezing" has become increasingly popular in the last few decades. Previous literature has suggested that there are gaps in counseling and expectations regarding the expected thaw rates and outcomes of preserved oocytes. DATA SOURCES: We conducted a systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses of seven databases (MEDLINE, EMBASE, Emcare, CINAHL, the Cochrane Library, Web of Science: Core Collection, and Scopus) until January 1st, 2024. The Risk Of Bias In Non-randomized Studies of Interventions tool was used for critical appraisal. Study selection and synthesis: All original human research that reported data for individuals who underwent autologous oocyte preservation for planned fertility delay (i.e., not for medical indications such as chemotherapy) were included for analysis. Meta-analysis was done using descriptive statistics and pooled prevalence rates. Title, and abstract screening and data extraction was conducted in duplicate by two independent reviewers for all studies until full agreement on eligibility was achieved through consensus-based discussion. RESULTS: After screening 1540 references, a total of 27 studies encompassing 13,724 patients were included. Follow-up ranged from 4 to 19 years, with a median follow-up time of 7 years. A total of 16,153 oocyte retrieval cycles for planned fertility delay were reported, with most individuals undergoing a single cryopreservation cycle. Overall, 10.8% of individuals returned to thaw their eggs with an aggregate oocyte survival rate of 79.52%. Implantation rate was 39.25%, clinical pregnancy rate was 32.5%, and ongoing pregnancy rate was 24.4% across the studies that reported these outcomes. A live birth was reported for 23.2% of individuals across all age groups who returned to thaw eggs. CONCLUSIONS AND RELEVANCE: Individuals should be counseled regarding the low return rates following oocyte preservation for planned fertility delay.

12.
Plant Physiol Biochem ; 214: 108907, 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38972242

RESUMO

The frequency and intensity of the occurrence of drought (D) events during winter are increasing in most areas of China. To explore the interactive effects of D and freezing temperature (F) on plants of endangered Cycas panzhihuaensis, some physiochemical characteristics and the lipid profile were determined. Drought and F stress had no or little impact on the traits of leaves, which, however, bleached following a combination of D and F treatment (DF). Drought treatment did not affect the chlorophyll fluorescence parameters and the flavonoid content of C. panzhihuaensis. Besides the increase in flavonoid content, a decrease of photochemical efficiency and an increase of heat dissipation were induced by both F and DF treatment, with the effects being greater in the latter treatment. The malondialdehyde content decreased significantly and the total antioxidant capacity increased significantly in the plants exposed to both D and DF treatments. The D treatment did not impact the amount of phospholipids but led to an accumulation of saccharolipids. Additionally, the amount of both phospholipids and saccharolipids remained unchanged following F treatment but decreased significantly following DF treatment compared with those of the control. The unsaturation level did not change significantly in most lipid classes of membrane glycerolipids following various stresses but increased significantly in phosphatidylserine, monogalactosylmonoacylglycerol, digalactosyldiacylglycerol and sulphoquinovosyldiacylglycerol following D or both D and F treatments. Generally, plants of C. panzhihuaensis showed relatively strong tolerance to individual D stress, while D aggravated the F-induced damage, which was likely caused by the degradation of the membrane glycerolipids.

13.
Food Chem ; 458: 140324, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38970954

RESUMO

In order to investigate the effects of multi-frequency ultrasound-assisted immersion freezing (MUIF) on the meat quality of Macrobrachium rosenbergii, tail meat was subjected to different MUIF treatments respectively, namely 20 + 40 kHz (MUIF-20 + 40), 20 + 60 kHz (MUIF-20 + 60), 40 + 60 kHz (MUIF-40 + 60) and 20 + 40 + 60 kHz (MUIF-20 + 40 + 60), and the immersion freezing (IF) as control. Results showed that average diameter of ice crystals was 28 µm in IF, and that was only 8 µm in MUIF-20 + 40 + 60. When compared to IF, MUIF alleviated oxidative deterioration of lipids and proteins, but only at higher ultrasound frequency (MUIF-40 + 60; MUIF-20 + 40 + 60). Carbonyl content of MUIF-20 + 40 + 60 was only 40% of that in IF. Similarly, protein denaturation was inhibited in MUIF (except for MUIF-20 + 40). Transmission electron microscopy showed greater distortion of the ultrastructural components in IF, MUIF-40 + 60, and MUIF-20 + 40 + 60, suggested by bended Z-line. In conclusion, MUIF can be an effective strategy to mitigate mechanical damage and protein deterioration in the meat of Macrobrachium rosenbergii.

14.
Front Med (Lausanne) ; 11: 1418684, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38966531

RESUMO

Introduction: Freezing of gait (FoG) is a significant issue for those with Parkinson's disease (PD) since it is a primary contributor to falls and is linked to a poor superiority of life. The underlying apparatus is still not understood; however, it is postulated that it is associated with cognitive disorders, namely impairments in executive and visuospatial functions. During episodes of FoG, patients may experience the risk of falling, which significantly effects their quality of life. Methods: This research aims to systematically evaluate the effectiveness of machine learning approaches in accurately predicting a FoG event before it occurs. The system was tested using a dataset collected from the Kaggle repository and comprises 3D accelerometer data collected from the lower backs of people who suffer from episodes of FoG, a severe indication frequently realized in persons with Parkinson's disease. Data were acquired by measuring acceleration from 65 patients and 20 healthy senior adults while they engaged in simulated daily life tasks. Of the total participants, 45 exhibited indications of FoG. This research utilizes seven machine learning methods, namely the decision tree, random forest, Knearest neighbors algorithm, LightGBM, and CatBoost models. The Gated Recurrent Unit (GRU)-Transformers and Longterm Recurrent Convolutional Networks (LRCN) models were applied to predict FoG. The construction and model parameters were planned to enhance performance by mitigating computational difficulty and evaluation duration. Results: The decision tree exhibited exceptional performance, achieving sensitivity rates of 91% in terms of accuracy, precision, recall, and F1- score metrics for the FoG, transition, and normal activity classes, respectively. It has been noted that the system has the capacity to anticipate FoG objectively and precisely. This system will be instrumental in advancing consideration in furthering the comprehension and handling of FoG.

15.
Res Sq ; 2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38946999

RESUMO

Vascularized composite allografts (VCAs) present unique challenges in transplant medicine, owing to their complex structure and vulnerability to ischemic injury. Innovative preservation techniques are crucial for extending the viability of these grafts, from procurement to transplantation. This study addresses these challenges by integrating cryoprotectant agent (CPA) optimization, advanced thermal tracking, and stepwise CPA loading strategies within an ex vivo rodent model. CPA optimization focused on various combinations, identifying those that effectively suppress ice nucleation while mitigating cytotoxicity. Thermal dynamics were monitored using invasive thermocouples and non-invasive FLIR imaging, yielding detailed temperature profiles crucial for managing warm ischemia time and optimizing cooling rates. The efficacy of stepwise CPA loading versus conventional flush protocols demonstrated that stepwise (un)loading significantly improved arterial resistance and weight change outcomes. In summary, this study presents comprehensive advancements in VCA preservation strategies, combining CPA optimization, precise thermal monitoring, and stepwise loading techniques. These findings hold potential implications for refining transplantation protocols and improving graft viability in VCA transplantation.

16.
Reprod Biomed Online ; 49(3): 104105, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38986195

RESUMO

RESEARCH QUESTION: Do the various forms of hormonal and non-hormonal contraceptives have any association with ovarian stimulation outcomes, such as oocyte yield and maturation, in patients undergoing planned oocyte cryopreservation (POC)? DESIGN: This retrospective cohort study included all patients who underwent POC cycles between 2011 and 2023. The use of types of contraception before a POC cycle was recorded. The study evaluated the median number of cumulus-oocyte complexes obtained after vaginal oocyte retrieval and the proportion of metaphase II oocytes that underwent vitrification among all the cohorts. RESULTS: A total of 4059 oocyte freezing cycles were included in the analysis. Eight types of contraceptive method were recognized in patients undergoing ovarian stimulation: intrauterine device (IUD), copper (n = 84); IUD, levonorgestrel low dose (<52 mg) (n = 37); IUD, levonorgestrel (n = 192); subdermal etonogestrel implant (n = 14); injectable medroxyprogesterone acetate (n = 11); etonogestrel vaginal ring (n = 142); combined oral contraceptive pills (n = 2349); and norelgestromin transdermal patch (n = 10). The control group included patients not using contraceptives or using barrier or calendar methods (n = 1220). Among all the cohorts the median number of cumulus-oocyte complexes retrieved during oocyte retrieval was comparable (P = 0.054), and a significant difference in oocyte maturity rate with median number of vitrified oocytes was found (P = 0.03, P < 0.001, respectively). After adjusting for confounders a multivariate analysis found no association between the type of contraceptive and proportion of metaphase II oocytes available for cryopreservation. CONCLUSIONS: Among the various forms of contraception, none was shown to have an adverse association with oocyte yield or maturation rate in patients undergoing POC.

17.
Meat Sci ; 216: 109593, 2024 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-38986236

RESUMO

High energy consumption and quality deterioration are major challenges in the meat freezing process. In this study, the energy consumption and qualities of frozen pork were investigated using three freezing methods: nonpackaged pork air freezing (NAF), contactless immersion freezing (PIF) and contact immersion freezing (NIF) with NaCl solution as a refrigerant. The results indicated that NIF could improve the energy conservation and freezing efficiency in >4 freezing treatment-times by increasing the unfrozen water content, decreasing the frozen heat load, shortening the freezing time and reducing evaporation loss. NIF could also increase the a* value of the pork and improve the water-holding capacity by facilitating the conversion of free water to immobilized-water. The two immersion freezing methods could reduce freezing-thawing loss and protein loss by alleviating muscle tissue freezing damage. These results provide a suitable application of immersion freezing with energy conservation, high efficiency and good quality of frozen-pork.

18.
Artigo em Inglês | MEDLINE | ID: mdl-38990423

RESUMO

Female fertility preservation is a rapidly growing field in medicine. Oocyte cryopreservation and assisted reproductive technique with vitrified-warmed oocytes have been successful with in vivo matured oocytes after conventional ovarian stimulation protocols. The use of in vitro matured oocytes after vitrification and warming has been limited. Capacitation in vitro maturation (CAPA-IVM) represents the latest refinement of IVM protocols and provides in vitro matured oocytes with improved competence. This case report describes the first successful live birth following oocyte vitrification from a CAPA-IVM cycle. This milestone achievement holds a significant promise to expand fertility preservation options and improve accessibility for women wishing to cryopreserve their eggs for future use.

19.
Plant Cell Physiol ; 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38957969

RESUMO

The INDUCER OF CBF EXPRESSION 1/C-REPEAT BINDING FACTOR (ICE1/CBF) pathway plays a crucial role in plant responses to cold stress, impacting growth and development. Here, we demonstrated that ATBS1-INTERACTING FACTOR 2 (AIF2), a non-DNA-binding basic helix-loop-helix transcription factor, positively regulates freezing tolerance through the ICE1/CBF-induced cold tolerance pathway in Arabidopsis. Cold stress transcriptionally upregulated AIF2 expression and induced AIF2 phosphorylation, thereby stabilizing the AIF2 protein during early stages of cold acclimation. The AIF2 loss-of-function mutant, aif2-1, exhibited heightened sensitivity to freezing before and after cold acclimation. In contrast, ectopic expression of AIF2, but not the C-terminal-deleted AIF2 variant, restored freezing tolerance. AIF2 enhanced ICE1 stability during cold acclimation and promoted the transcriptional expression of CBFs and downstream cold-responsive genes, ultimately enhancing plant tolerance to freezing stress. MITOGEN-ACTIVATED PROTEIN KINASES 3 and 6 (MPK3/6), known negative regulators of freezing tolerance, interacted with and phosphorylated AIF2, subjecting it to protein degradation. Furthermore, transient co-expression of MPK3/6 with AIF2 and ICE1 downregulated AIF2/ICE1-induced transactivation of CBF2 expression. AIF2 interacted preferentially with BIN2 and MPK3/6 during the early and later stages of cold acclimation, respectively, thereby differentially regulating AIF2 activity in a cold acclimation time-dependent manner. Moreover, AIF2 acted additively in a gain-of-function mutant of BRASSINAZOLE-RESISTANT 1 (BZR1; bzr1-1D) and a triple knockout mutant of BRASSINOSTEROID-INSENSITIVE 2 (BIN2) and its homologs (bin2bil1bil2) to induce CBFs-mediated freezing tolerance. This suggests that cold-induced AIF2 coordinates freezing tolerance along with BZR1 and BIN2, key positive and negative components, respectively, of brassinosteroid signaling pathways.

20.
Plant Physiol ; 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38875158

RESUMO

Cold stress declines the quality and yield of tea, yet the molecular basis underlying cold tolerance of tea plants (Camellia sinensis) remains largely unknown. Here, we identified a circadian rhythm component LUX ARRHYTHMO (LUX) that potentially regulates cold tolerance of tea plants through a genome-wide association study and transcriptomic analysis. The expression of CsLUX phased with sunrise and sunset and was strongly induced by cold stress. Genetic assays indicated that CsLUX is a positive regulator of freezing tolerance in tea plants. CsLUX was directly activated by CsCBF1 and repressed the expression level of CsLOX2, which regulates the cold tolerance of tea plants through dynamically modulating jasmonic acid content. Furthermore, we showed that the CsLUX-CsJAZ1 complex attenuated the physical interaction of CsJAZ1 with CsICE1, liberating CsICE1 with transcriptional activities to withstand cold stress. Notably, a single-nucleotide variation of C-to-A in the coding region of CsLUX was functionally validated as the potential elite haplotype for cold response, which provided valuable molecular markers for future cold resistance breeding in tea plants.

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