tolerance mechanism
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Sensors ◽  
2022 ◽  
Vol 22 (1) ◽  
pp. 401
Author(s):  
Sidra Abid Syed ◽  
Munaf Rashid ◽  
Samreen Hussain ◽  
Fahad Azim ◽  
Hira Zahid ◽  
...  

Software-defined network (SDN) and vehicular ad-hoc network (VANET) combined provided a software-defined vehicular network (SDVN). To increase the quality of service (QoS) of vehicle communication and to make the overall process efficient, researchers are working on VANET communication systems. Current research work has made many strides, but due to the following limitations, it needs further investigation and research: Cloud computing is used for messages/tasks execution instead of fog computing, which increases response time. Furthermore, a fault tolerance mechanism is used to reduce the tasks/messages failure ratio. We proposed QoS aware and fault tolerance-based software-defined V vehicular networks using Cloud-fog computing (QAFT-SDVN) to address the above issues. We provided heuristic algorithms to solve the above limitations. The proposed model gets vehicle messages through SDN nodes which are placed on fog nodes. SDN controllers receive messages from nearby SDN units and prioritize the messages in two different ways. One is the message nature way, while the other one is deadline and size way of messages prioritization. SDN controller categorized in safety and non-safety messages and forward to the destination. After sending messages to their destination, we check their acknowledgment; if the destination receives the messages, then no action is taken; otherwise, we use a fault tolerance mechanism. We send the messages again. The proposed model is implemented in CloudSIm and iFogSim, and compared with the latest models. The results show that our proposed model decreased response time by 50% of the safety and non-safety messages by using fog nodes for the SDN controller. Furthermore, we reduced the execution time of the safety and non-safety messages by up to 4%. Similarly, compared with the latest model, we reduced the task failure ratio by 20%, 15%, 23.3%, and 22.5%.


2021 ◽  
Vol 23 (1) ◽  
pp. 154
Author(s):  
Soraya Mousavi ◽  
Roberto Mariotti ◽  
Maria Cristina Valeri ◽  
Luca Regni ◽  
Emanuele Lilli ◽  
...  

Climate change, currently taking place worldwide and also in the Mediterranean area, is leading to a reduction in water availability and to groundwater salinization. Olive represents one of the most efficient tree crops to face these scenarios, thanks to its natural ability to tolerate moderate salinity and drought. In the present work, four olive cultivars (Koroneiki, Picual, Royal de Cazorla and Fadak86) were exposed to high salt stress conditions (200 mM of NaCl) in greenhouse, in order to evaluate their tolerance level and to identify key genes involved in salt stress response. Molecular and physiological parameters, as well as plant growth and leaves’ ions Na+ and K+ content were measured. Results of the physiological measurements showed Royal de Cazorla as the most tolerant cultivar, and Fadak86 and Picual as the most susceptible ones. Ten candidate genes were analyzed and their complete genomic, CDS and protein sequences were identified. The expression analysis of their transcripts through reverse transcriptase quantitative PCR (RT-qPCR) demonstrated that only OeNHX7, OeP5CS, OeRD19A and OePetD were upregulated in tolerant cultivars, thus suggesting their key role in the activation of a salt tolerance mechanism.


Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2586
Author(s):  
Zhi Li ◽  
Danfeng Bai ◽  
Yunpeng Zhong ◽  
Muhammad Abid ◽  
Xiujuan Qi ◽  
...  

Rootstocks from Actinidia valvata are much more tolerant to waterlogging stress than those from Actinidia deliciosa, which are commonly used in kiwifruit production. To date, the tolerance mechanism of A. valvata rootstocks’ adaptation to waterlogging stress has not been well explored. In this study, the responses of KR5 (A. valvata) and ‘Hayward’ (A. deliciosa) to waterlogging stress were compared. Results showed that KR5 plants performed much better than ‘Hayward’ during waterlogging by exhibiting higher net photosynthetic rates in leaves, more rapid formation of adventitious roots at the base of stems, and less severe damage to the main root system. In addition to morphological adaptations, metabolic responses of roots including sufficient sucrose reserves, modulated adjustment of fermentative enzymes, avoidance of excess lactic acid and ethanol accumulation, and promoted accumulation of total amino acids all possibly rendered KR5 plants more tolerant to waterlogging stress compared to ‘Hayward’ plants. Lysine contents of roots under waterlogging stress were increased in ‘Hayward’ and decreased in KR5 compared with their corresponding controls. Overall, our results revealed the morphological and metabolic adaptations of two kiwifruit rootstocks to waterlogging stress, which may be responsible for their genotypic difference in waterlogging tolerance.


2021 ◽  
Vol 12 ◽  
Author(s):  
Ru Bu ◽  
Bing Yan ◽  
Huijie Sun ◽  
Mengcheng Zhou ◽  
Huashan Bai ◽  
...  

Various agricultural products used in food fermentation are polluted by heavy metals, especially copper, which seriously endangers human health. Methods to remove copper with microbial strategies have gained interests. A novel Meyerozyma guilliermondii GXDK6 could survive independently under high stress of copper (1400 ppm). The copper tolerance mechanism of GXDK6 was revealed by integrated omics in this work. Whole-genome analysis showed that nine genes (i.e., CCC2, CTR3, FRE2, GGT, GST, CAT, SOD2, PXMP4, and HSP82) were related to GXDK6 copper tolerance. Copper stress elevated glutathione metabolism-related gene expression, glutathione content, and glutathione sulfur transferase activity, suggesting enhanced copper conjugation and detoxification in cells. The inhibited copper uptake by Ctr3 and enhanced copper efflux by Ccc2 contributed to the decrease in intracellular copper concentration. The improved expression of antioxidant enzyme genes (PXMP4, SOD2, and CAT), accompanied by the enhanced activities of antioxidant enzymes (peroxidase, superoxide dismutase, and catalase), decreased copper-induced reactive oxygen species production, protein carbonylation, lipid peroxidation, and cell death. The metabolite D-mannose against harsh stress conditions was beneficial to improving copper tolerance. This study contributed to understanding the copper tolerance mechanism of M. guilliermondii and its application in removing copper during fermentation.


2021 ◽  
Author(s):  
Hyun-Soo Kim

Abstract Objective The aim of this study was to identify genes related to a freeze-thaw tolerance and to elucidate the tolerance mechanism in yeast Saccharomyces cerevisiae as an appropriate eukaryote model. Results In this study, one tolerant strain under exposure to freeze-thaw stress was isolated by screening a transposon-mediated mutant library and the disrupted gene was identified to be YCP4. In addition, this phenotype related to freeze-thaw tolerance was comfirmed by deletion and overexpressing of this corresponding gene. This mutant strain showed a freeze-thaw tolerance by the reduction in the intracellular level of reactive oxygen species (ROS) and the activation of the MSN2/4 and STRE-mediated genes such as CTT1 and HSP12. Conclusions Disruption of YCP4 in S. cerevisiae results in increased tolerance to freeze-thaw stress.


2021 ◽  
Author(s):  
Suphia Rafique

Abiotic stresses are the major threat to crops regardless of their nature, duration, and frequency, their occurrence either singly, and or combination is deleterious for the plant growth and development. Maize is the most important crop largely grown in the tropical regions in the summer rainy season, often facing a stress combination of drought and waterlogging. We previously showed under multiple stresses up-regulated leaf proteins of maize plants were involved to enhance the tolerance mechanism of tolerant genotype. Whereas, in susceptible genotypes up-regulated proteins ameliorate to survive the stressful condition. Further to understand the response of roots proteome under multiple stresses was determined using the 2DE technique. The results of the root proteome show the up-regulated proteins of CML49 genotype (tolerant) are involved in enhancing the N content, cell wall remodeling, and acclimatization during the stresses. Up-regulated proteins of CML100 genotype (sensitive) are stressed markers of roots' primary and secondary metabolism. However, the root proteome of both genotypes correlates with the leaf proteome (previous). Therefore, the present study and our previous results provide comprehensive insight into the molecular mechanisms of tolerance in multiple abiotic stresses of maize plants.


2021 ◽  
Vol 12 ◽  
Author(s):  
Dongsheng Hu ◽  
Zhiquan Wang ◽  
Mingxiong He ◽  
Yuanyuan Ma

Furfural is a major inhibitor in lignocellulose hydrolysate for Zymomonas mobilis. A mutant F211 strain with high furfural tolerance was obtained from our previous study. Thus, its key tolerance mechanism was studied in the present study. The function of mutated genes in F211 was identified by functional complementation experiments, revealing that the improved furfural tolerance was resulted from the C493T mutation of the ZCP4_0270 gene promoting cell flocculation and the mutation (G1075A)/downregulation of ZCP4_0970. Comparative transcriptome analysis revealed 139 differentially expressed genes between F211 and the control, CP4, in response to furfural stress. In addition, the reliability of the RNA-Seq data was also confirmed. The potential tolerance mechanism was further demonstrated by functional identification of tolerance genes as follows: (I) some upregulated or downregulated genes increase the levels of NAD(P)H, which is involved in the reduction of furfural to less toxic furfuryl alcohol, thus accelerating the detoxification of furfural; (II) the mutated ZCP4_0270 and upregulated cellulose synthetase gene (ZCP4_0241 and ZCP4_0242) increased flocculation to resist furfural stress; (III) upregulated molecular chaperone genes promote protein synthesis and repair stress-damaged proteins; and (IV) transporter genes ZCP4_1623–1,625 and ZCP4_1702–1703 were downregulated, saving energy for cell growth. The furfural-tolerant mechanism and corresponding functional genes were revealed, which provides a theoretical basis for developing robust chassis strains for synthetic biology efforts.


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