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Trehalose Metabolism in Plants under Abiotic Stresses
Published in Hasanuzzaman Mirza, Nahar Kamrun, Fujita Masayuki, Oku Hirosuke, Tofazzal M. Islam, Approaches for Enhancing Abiotic Stress Tolerance in Plants, 2019
Qasim Ali, Sumreena Shahid, Shafaqat Ali, Muhammad Tariq Javed, Naeem Iqbal, Noman Habib, Syed Makhdoom Hussain, Shahzad Ali Shahid, Zahra Noreen, Abdullah Ijaz Hussain, Muhammad Zulqurnain Haider
Huge work has been reported about the role of trehalose in desiccation tolerance of bacterial species. Under desiccation stress, Nostoc commune accumulated a large amount of trehalose, along with other polysaccharides that have roles in stress tolerance (Cameron, 1962; Sakamoto et al., 2009; Klahn and Hagemann, 2011). Among others that accumulate high amounts of trehalose under stress are Phormidium autumnale and Chroococcidiopsis sp. (Hershkowitz et al., 1991). It has been found that on rewatering, the trehalose contents decrease (Sakamoto et al., 2009). However, trehalose accumulation under desiccation stress is not same in all studies. For example, in Anabena and Nostoc flagelliforme, the accumulated content of trehalose is not enough to work as a molecular chaperone for related genes (Higo et al.; 2006; Wu et al., 2010).
Effects of Climate Change on Aquatic Bryophytes
Published in Donat-P. Häder, Kunshan Gao, Aquatic Ecosystems in a Changing Climate, 2018
Javier Martínez-Abaigar, Encarnación Núñez-Olivera
In areas where less precipitation and more evaporation have been predicted (for example, Mediterranean climate zones), situations of low water levels and flows will be more frequent and long, impacting negatively on OAB. At the first moment, this will occur because of decreasing turbulence and free CO2 availability, which is needed by OAB for photosynthesis (Glime 2011; see below). Then, longer periods of emersion and desiccation, with drastic reductions or complete cessation of growth, will impede OAB development. These processes would be associated to increasing temperature and levels of photosynthetic and UV irradiances while bryophytes desiccate. Even under these severely unfavorable conditions, some OAB (such as the mosses Fontinalis antipyretica and Platyhypnidium riparioides) can survive taking advantage of extremely desiccation-tolerant stems that, despite looking black and dead, can resprout and produce new healthy branches under subsequent rehydration. Additional physiological mechanisms of desiccation tolerance can be developed in this kind of species if dehydration rate is slow (Cruz de Carvalho et al. 2012). In contrast, less desiccation-tolerant species (like the softer aquatic liverworts of the genus Jungermannia) may die under these severe conditions. In the long-term, longer periods of low flow or complete dryness of water courses, or a higher frequency of desiccation-rehydration cycles of bryophytes (Glime 2011, 2014), can lead to changes in the species composition of the communities. Firstly, there could be an increasing predominance of aquatic but desiccation-tolerant mosses, which would have a higher competitive advantage than, for example, aquatic liverworts. Finally, aquatic communities would disappear and would be replaced by non-aquatic bryophytes typically growing on soils and even herbs or shrubs.
Influence of type and concentration of lyoprotectants, storage temperature and storage duration on cell viability and antibacterial activity of freeze-dried lactic acid bacterium, Lactococcus lactis Gh1
Published in Drying Technology, 2022
Roslina Jawan, Sahar Abbasiliasi, Joo Shun Tan, Mohd Rizal Kapri, Shuhaimi Mustafa, Murni Halim, Arbakariya B. Ariff
Results from this study demonstrated that most monosaccharides have better protective effect compared to that of disaccharides. Ambros et al. [31] stated that low molecular weight compounds are excellent as protective agents due to their great adsorption to the cytoplasm membrane. This might explain the suitability of galactose to protect the cells during the freeze-drying process. Desiccation tolerance by forming hydrogen bonds to proteins during drying had increased in the presence of sugar, which maintained the tertiary protein structure in the absence of water. This result is in agreement with that of Chen et al. [32] who found that galactose has markedly improved the viability of LAB in freeze-dried kefir.