Relevant bibliographies by topics / Desiccation

Academic literature on the topic 'Desiccation'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 April 2023

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Journal articles on the topic "Desiccation"

Englert, John M., Keith Warren, Leslie H. Fuchigami, and Tony H. H. Chen. "Antidesiccant Compounds Improve the Survival of Bare-root Deciduous Nursery Trees." Journal of the American Society for Horticultural Science 118, no. 2 (March 1993): 228–35. http://dx.doi.org/10.21273/jashs.118.2.228.

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Desiccation stress during the postharvest handling of bare-root deciduous trees can account for dieback and poor regrowth after transplanting. Desiccation tolerance of three bare-root deciduous hardwood species was determined at monthly harvest intervals from Sept. 1990 through Apr. 1991. Among the three species tested red oak (Quercus rubra L.) was most tolerant to desiccation, followed by Norway maple (Acer platanoides L.) and Washington hawthorn (Crataegus phaenopyrum Medic.). Maximum desiccation tolerance of all three species occurred during the January and February harvests. Of 20 film-forming compounds tested, the antidesiccant Moisturin was the most effective in reducing water loss from bare-root trees during desiccation stress and in improving survival and plant performance during re-establishment in the laboratory, greenhouse, and field. Moisturin-treated plants lost up to 80% less water than untreated plants. Washington hawthorn seedlings treated with Moisturin before severe desiccating conditions had the highest survival, lowest dieback/plant, and highest root growth ratings. The results indicate that Moisturin is an effective means of overcoming postharvest desiccation stress in desiccation sensitive plants, such as Washington hawthorn.

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Meichssner, Rafael, Nadja Stegmann, Anna-Sarah Cosin, Dagobert Sachs, Matthias Bressan, Henriette Marx, Peter Krost, and Rüdiger Schulz. "Control of fouling in the aquaculture of Fucus vesiculosus and Fucus serratus by regular desiccation." Journal of Applied Phycology 32, no. 6 (October 7, 2020): 4145–58. http://dx.doi.org/10.1007/s10811-020-02274-2.

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AbstractFouling is a major problem in seaweed aquaculture and one of the main obstacles during the domestication process for new culture species. During first attempts to cultivate Fucus vesiculosus and Fucus serratus in the Kiel fjord (Western Baltic Sea), fouling by the epizoans Electra pilosa, Mytilus sp., and Amphibalanus improvisus rendered the production of marketable biomass impossible. This study tested (1) if regular desiccation by air exposure is effective in decreasing the abundance and size of foulers and (2) if and how regular desiccation affects the growth performance of the cultivated Fucus thalli. For this purpose, thalli of F. vesiculosus and F. serratus were cultivated freely floating in baskets directly deployed in the fjord and desiccated to defined percentages of the wet weight (ww) by air exposure. The treatments comprised controls and desiccations of different intensities (from 90 to 40% of ww) and at different frequencies (1× week−1, 3× week−1). Growth rates of both Fucus species were not or only slightly reduced by the desiccation treatments. The final harvested biomass of F. vesiculosus under frequent mild desiccations (3× week−1 to 80% of ww) was even higher than the biomass of undesiccated controls. The size of the epizoans E. pilosa and A. improvisus was significantly reduced by the desiccation treatments and the abundance of all epizoan species was drastically reduced by the desiccation regimes. Frequent mild desiccations (F. vesiculosus: 3× week−1 to 80% of ww, F. serratus: 3× week−1 to 90% of ww) proved to be most effective and decreased the epizoan ww share of the total harvest from 13.0 ± 4.8% in the control to 1.8 ± 0.2% for F. vesiculosus and from 19.1 ± 2.7 to 1.0 ± 0.1% for F. serratus. Thus, desiccation seems to be an effective measure for the production of clean Fucus biomass in culture which is necessary for further valorization. A technical solution for the implementation of this procedure in large-scale cultures remains to be developed.

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Yang, Yujing, Deguang Liu, Xiaoming Liu, Biyao Wang, and Xiaoqin Shi. "Divergence of Desiccation-Related Traits in Sitobion avenae from Northwestern China." Insects 11, no. 9 (September 11, 2020): 626. http://dx.doi.org/10.3390/insects11090626.

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The impact of drought on insects has become increasingly evident in the context of global climate change, but the physiological mechanisms of aphids’ responses to desiccating environments are still not well understood. We sampled the wheat aphid Sitobion avenae (Fabricius) (Hemiptera: Aphididae) from arid areas of northwestern China. Both desiccation-resistant and -nonresistant genotypes were identified, providing direct evidence of genetic divergence in desiccation resistance of S. avenae. Resistant genotypes of wingless S. avenae showed longer survival time and LT50 under the desiccation stress (i.e., 10% relative humidity) than nonresistant genotypes, and wingless individuals tended to have higher desiccation resistance than winged ones. Both absolute and relative water contents did not differ between the two kinds of genotypes. Resistant genotypes had lower water loss rates than nonresistant genotypes for both winged and wingless individuals, suggesting that modulation of water loss rates could be the primary strategy in resistance of this aphid against desiccation stress. Contents of cuticular hydrocarbons (CHC) (especially methyl-branched alkanes) showed significant increase for both resistant and nonresistant genotypes after exposure to the desiccation stress for 24 h. Under desiccation stress, survival time was positively correlated with contents of methyl-branched alkanes for resistant genotypes. Thus, the content of methyl-branched alkanes and their high plasticity could be closely linked to water loss rate and desiccation resistance in S. avenae. Our results provide insights into fundamental aspects and underlying mechanisms of desiccation resistance in aphids, and have significant implications for the evolution of aphid populations in the context of global warming.

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Ivanchina, Ludmila A., and Sergei V. Zalesov. "The effect of spruce plantation density on resilience of mixed forests in the Perm Krai." Journal of Forest Science 65, No. 7 (July 31, 2019): 263–71. http://dx.doi.org/10.17221/14/2019-jfs.

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Over the course of the last few decades, many countries across the globe have experienced mass desiccation of spruce plantations. The subject of our research was the spruce forests of the Russian Perm Krai’s mixed forest zone. Spruce is a shade–tolerant tree species and low plantation density may adversely affect the spruce health. The aim of this research is to establish how influential the spruce stand density is on causing desiccation in mixed zones in the Perm Krai. The results of an on-site survey which had recorded spruce desiccation in 2017 were analysed. Within the boundaries of the aforementioned forest areas, 2017 saw the desiccation of spruce trees in 301 forest allotments covering an area of 5,343.7 ha. The value of the weighted average category of spruce forest health in Prikamye varies from 2.7 (severely weakened) to 4.2 (desiccating), and the percentage of the volume of spruce deadwood varies from 17% to 59.5%. When the spruce stand density rises from 0.4 to 0.8, spruce stand resilience to desiccation increases.

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Keosentse, Onalethata, Reyard Mutamiswa, and Casper Nyamukondiwa. "Interaction effects of desiccation and temperature stress resistance across Spodoptera frugiperda (Lepidoptera, Noctuidae) developmental stages." NeoBiota 73 (May 16, 2022): 87–108. http://dx.doi.org/10.3897/neobiota.73.76011.

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Insects encounter multiple overlapping physiologically challenging environmental stressors in their habitats. As such, the ability of insects to withstand these stressors singly or interactively is fundamental in population persistence. Following its invasion in Africa, Spodoptera frugiperda (Lepidoptera: Noctuidae) has successfully established and spread in most parts of the continent. However, the mechanisms behind its successful survival across arid and semi-arid African environments are relatively unknown. Here, we investigated the water balance of S. frugiperda across its developmental stages. Given the relationships between desiccation stress, temperature stress and other life history traits in arid ecosystems, we also measured interaction effects across metrics of these traits. Specifically, we measured basal body water content (BWC), water loss rates (WLRs) and the effects of desiccation pre-treatment on critical thermal minimum (CTmin), critical thermal maximum (CTmax) and fecundity. Body water content and WLR increased with age across larval instars. However, the effects of desiccation environments on WLRs were more dramatic for 5th and 6th larval instars. The 5th and 6th instars exhibited highest BWC and magnitude of WLRs plastic responses following desiccation treatment. The effects of desiccation pre-treatment on temperature tolerance were less apparent, only significantly improving CTmin in 2nd and 3rd larval instars and reducing CTmax in 5th instars. In addition, desiccation pre-treatment showed no significant effects on fecundity. These results show that water balance traits differ with developmental stage, while the effects of desiccation pre-treatment were more dramatic and inconclusive. The differential desiccation resistance, high proportional BWC and no desiccation pre-treatment effects on fecundity may help the species survive in arid and semi-arid environments. This information provides insights into understanding S. frugiperda survival under desiccating arid and semi-arid tropical environments and is significant in predicting pest outbreaks.

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Bauce, É., and E. Han. "Desiccation resistance in pre-diapause, diapause and post-diapause larvae of Choristoneura fumiferana (Lepidoptera: Tortricidae)." Bulletin of Entomological Research 91, no. 5 (October 2001): 321–26. http://dx.doi.org/10.1079/ber2001119.

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AbstractDesiccation resistance was examined in pre-diapause, diapause and post-diapause larvae of the spruce budworm, Choristoneura fumiferana (Clemens), in terms of passive water evaporation under three desiccation conditions: freeze-drying, desiccant-drying at 2°C and desiccant-drying 18°C. Diapausing second instar larvae and post-diapause non-feeding second instar larvae showed strongest desiccation resistance: a significant amount of water was retained after repeated drying under desiccating conditions, while pre-diapause first instar larvae and post-diapause feeding instar larvae lost almost all their water content after one or two drying cycles. A hibernaculum covering had no effect on water evaporation. While dead larvae tended to lose significantly more water than their living counterparts, particularly among first instar larvae, such an impact much weaker among diapausing second instar larvae. Desiccation resistance was lost when post-diapause second instar larvae were allowed access to water while the level of desiccation resistance was maintained or enhanced when the larvae did not have access to water. These results are discussed the context of overwintering ecology of the species and possible mechanisms for the desiccation resistance are also discussed.

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Anderson, Kimberly L., Ethel E. Apolinario, and Kevin R. Sowers. "Desiccation as a Long-Term Survival Mechanism for the Archaeon Methanosarcina barkeri." Applied and Environmental Microbiology 78, no. 5 (December 22, 2011): 1473–79. http://dx.doi.org/10.1128/aem.06964-11.

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ABSTRACTViable methanogens have been detected in dry, aerobic environments such as dry reservoir sediment, dry rice paddies and aerobic desert soils, which suggests that methanogens have mechanisms for long-term survival in a desiccated state. In this study, we quantified the survival rates of the methanogenic archaeonMethanosarcina barkeriafter desiccation under conditions equivalent to the driest environments on Earth and subsequent exposure to different stress factors. There was no significant loss of viability after desiccation for 28 days for cells grown with either hydrogen or the methylotrophic substrates, but recovery was affected by growth phase, with cells desiccated during the stationary phase of growth having a higher rate of recovery after desiccation. Synthesis of methanosarcinal extracellular polysaccharide (EPS) significantly increased the viability of desiccated cells under both anaerobic and aerobic conditions compared with that of non-EPS-synthesizing cells. DesiccatedM. barkeriexposed to air at room temperature did not lose significant viability after 28 days, and exposure ofM. barkerito air after desiccation appeared to improve the recovery of viable cells compared with that of desiccated cells that were never exposed to air. DesiccatedM. barkeriwas more resistant to higher temperatures, and although resistance to oxidative conditions such as ozone and ionizing radiation was not as robust as in other desiccation-resistant microorganisms, the protection mechanisms are likely adequate to maintain cell viability during periodic exposure events. The results of this study demonstrate that after desiccationM. barkerihas the innate capability to survive extended periods of exposure to air and lethal temperatures.

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Gibbs, A. G., A. K. Chippindale, and M. R. Rose. "Physiological mechanisms of evolved desiccation resistance in Drosophila melanogaster." Journal of Experimental Biology 200, no. 12 (June 1, 1997): 1821–32. http://dx.doi.org/10.1242/jeb.200.12.1821.

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We investigated physiological characters associated with water balance in laboratory populations of Drosophila melanogaster selected for resistance to desiccating conditions for over 100 generations. Five replicate, outbred, desiccation-selected (D) populations were compared with their control (C) populations. Water loss rates of female D flies were approximately 40% lower than those of C females. Although excretory water loss was reduced in desiccation-selected flies, it comprised less than 10% of total water loss, indicating that the D populations have evolved reduced cuticular and/or respiratory water loss rates. Total surface lipid amounts did not differ between the C and D flies. Cuticular hydrocarbons from D flies were longer than those from C flies and melted at slightly higher temperatures, possibly contributing to reduced water loss rates. Desiccation-selected flies contained approximately 30% more bulk water than controls, as well as more glycogen. However, total metabolic water stores did not differ between the stocks owing to higher lipid levels in the C populations. The ability to tolerate water loss, as measured by water content at the time of death, did not differ between D and C flies. Thus, evolution of increased desiccation resistance has occurred by multiple physiological mechanisms, but some potential adaptive differences have not evolved.

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Ferebee, J. Harrison, Charles W. Cahoon, Michael L. Flessner, David B. Langston, Ramon Arancibia, Thomas E. Hines, Hunter B. Blake, and M. Carter Askew. "Comparison of Diquat, Glufosinate, and Saflufenacil for Desiccation of ‘Dark Red Norland’ Potato." HortTechnology 29, no. 5 (October 2019): 643–48. http://dx.doi.org/10.21273/horttech04327-19.

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Chemical desiccants are commonly used to regulate tuber size, strengthen skin, and facilitate harvest for potato (Solanum tuberosum) production. Glufosinate is labeled for potato vine desiccation; however, limited data are available. Saflufenacil, a protoporphyrinogen oxidase–inhibiting herbicide, is an effective desiccant in other crops. Field research was conducted to evaluate glufosinate and saflufenacil as desiccants applied to ‘Dark Red Norland’ potato. Desiccants consisted of diquat, glufosinate, saflufenacil, glufosinate plus carfentrazone, and glufosinate plus saflufenacil applied at three timings, DESIC-1, DESIC-2, and DESIC-3, when size B potatoes averaged 43%, 31%, and 17% of total potato weight. Potato vine desiccation was more difficult at DESIC-1 and DESIC-2 because of immature vines. Diquat was the most effective desiccant 7 days after treatment (DAT), desiccating potato vines 88% at DESIC-1 7 DAT. Glufosinate alone desiccated potato vines 65% at the same timing; however, carfentrazone and saflufenacil added to glufosinate increased vine desiccation 8% and 16% compared with glufosinate alone, respectively. Vine desiccation by all treatments ranged 99% to 100% at 14 DAT. Desiccant and timing effects on skin set were determined using a torque meter before harvest. Skin set resulting from all desiccants and timings ranged between 1.88 and 2 lb-inch, and no significant differences were observed. No significant differences in yield were noted among desiccants. This research indicates that glufosinate and saflufenacil are suitable alternatives to diquat for potato vine desiccation; however, safety of saflufenacil applied to potatoes before harvest has not been determined.

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Cytryn, Eddie J., Dipen P. Sangurdekar, John G. Streeter, William L. Franck, Woo-suk Chang, Gary Stacey, David W. Emerich, Trupti Joshi, Dong Xu, and Michael J. Sadowsky. "Transcriptional and Physiological Responses of Bradyrhizobium japonicum to Desiccation-Induced Stress." Journal of Bacteriology 189, no. 19 (July 27, 2007): 6751–62. http://dx.doi.org/10.1128/jb.00533-07.

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ABSTRACT The growth and persistence of rhizobia and bradyrhizobia in soils are negatively impacted by drought conditions. In this study, we used genome-wide transcriptional analyses to obtain a comprehensive understanding of the response of Bradyrhizobium japonicum to drought. Desiccation of cells resulted in the differential expression of 15 to 20% of the 8,480 B. japonicum open reading frames, with considerable differentiation between early (after 4 h) and late (after 24 and 72 h) expressed genes. While 225 genes were universally up-regulated at all three incubation times in response to desiccation, an additional 43 and 403 up-regulated genes were common to the 4/24- and 24/72-h incubation times, respectively. Desiccating conditions resulted in the significant induction (>2.0-fold) of the trehalose-6-phosphate synthetase (otsA), trehalose-6-phosphate phosphatase (otsB), and trehalose synthase (treS) genes, which encode two of the three trehalose synthesis pathways found in B. japonicum. Gene induction was correlated with an elevated intracellular concentration of trehalose and increased activity of trehalose-6-phosphate synthetase, collectively supporting the hypothesis that this disaccharide plays a prominent and important role in promoting desiccation tolerance in B. japonicum. Microarray data also indicated that σ54- and σ24-associated transcriptional regulators and genes encoding isocitrate lyase, oxidative stress responses, the synthesis and transport of exopolysaccharides, heat shock response proteins, enzymes for the modification and repair of nucleic acids, and the synthesis of pili and flagella are also involved in the response of B. japonicum to desiccation. Polyethylene glycol-generated osmotic stress induced significantly fewer genes than those transcriptionally activated by desiccation. However, 67 genes were commonly induced under both conditions. Taken together, these results suggest that B. japonicum directly responds to desiccation by adapting to changes imparted by reduced water activity, such as the synthesis of trehalose and polysaccharides and, secondarily, by the induction of a wide variety of proteins involved in protection of the cell membrane, repair of DNA damage, stability and integrity of proteins, and oxidative stress responses.

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Dissertations / Theses on the topic "Desiccation"

Potts, Malcolm. "Desiccation tolerance." Thesis, Durham University, 1995. http://etheses.dur.ac.uk/9528/.

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Despite the fundamental significance of desiccation in determining the distributions and activities of living organisms, there is virtually no insight as to the state of the cytoplasm of an air-dried, or even a wet, cell. In bacterial cells that have been subjected to air-drying the evaporation of free cytoplasmic water (Vf) can be instantaneous, and an equilibrium between cell-bound water (VQ and the environmental water (vapor) potential (Ψwv)) may be achieved very rapidly. In the air-dried state some bacteria survive only for seconds, others can tolerate desiccation for thousands, perhaps for millions, of years. The means by which certain cells, the anhydrobiotes, overcome and then tolerate acute water deficit remains one of the most intractable problems in cell biology. One such anhydrobiote, the cyanobacterium Nostoc commune, is cosmopolitan, its colonies form visually-conspicuous and abundant growths in situ, and it constitutes an ecologically-significant component of terrestial nitrogen-fixing communities. The cyanobacteria are phylogenetically-significant organisms that provide model systems for the study of a broad range of problems in cell biology. The studies described in this thesis established the molecular ecology and cell biology of Nostoc commune, and they provide a chronicle of the development of this microorganism as the prokaryotic model for the anhydrobiotic cell. In the design of experiments to investigate this problem the bias was, and remains, this: to understand desiccation tolerance, understand an organism that tolerates desiccation. The thesis documents an investigation into the consequences of acute cell-water deficit and the cellular basis for desiccation tolerance. An eclectic approach has been adopted to study desiccation tolerance and it includes the application of techniques of cell biology, biochemistry, microbiology, molecular biology, structural biology and biophysics.

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Bohnert, Hans J. "What makes desiccation tolerable?" BioMed Central, 2000. http://hdl.handle.net/10150/610140.

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Chaibenjawong, Plykaeow. "Desiccation Tolerance in Staphylococcus aureus." Thesis, University of Sheffield, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522502.

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Wortmann, Heid. "Sedimentation and desiccation of gold mines." Pretoria : [s.n.], 2007. http://upetd.up.ac.za/thesis/available/etd-11052007-152710.

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Atique, Alvis. "Investigation of desiccation cracks in drying soil." Thesis, University of Strathclyde, 2013. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=20835.

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This research investigates desiccation cracking behaviour of a fill material from a flood embankment along the Bengawan Solo River in East Java, Indonesia, an area that is prone to extremes in flooding and drying. A detailed study of the previous works on this topic showed the absence of fully-monitored laboratory tests dedicated to desiccation cracking behaviour. This study combined traditional and new techniques to characterise desiccation cracking behaviour in this material in a suite of laboratory tests. Desiccation plate tests were conducted to gain basic knowledge of the cracking behaviour of Bengawan Solo soil and identify the influences of plate shape on test results. Crack initiation, evolution, and final pattern were studied in detail. Results of the experiments showed that plate geometry had minimal effect on cracking behaviour except for the final cracking pattern. Crack initiation and evolution was characterised with a 2D/3D profile laser sensor coupled to a motion controller that allowed scanning of the overall surface of the drying soil. The system developed for this work was used to track the three most relevant variables associated with the behavior of soils during desiccation: volume change, water loss, and evolving crack network morphology. With this new method, the evolution of crack aperture, crack depth, surface contour levels (settlements) and evolution of global volume change were captured in real time, significantly improving upon previous methods for crack monitoring. Finally, the effects of moisture content and dry density on tensile strength during cracking was investigated at two states: reconstituted and compacted. Microstructural investigation illustrated the fabric changes during drying at two states to complement the experimental results for tensile strength. The comparison of tensile strength between reconstituted and compacted state has been found promising and believed to be useful in earthwork construction projects.

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Dace, Halford. "Metabolomics of desiccation tolerance in Xerophyta humilis." Master's thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/9111.

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Includes bibliographical references
Resurrection plants are unique in the ability to survive near complete water loss in vegetative tissues without loss of viability. In order to do so, they employ multifaceted strategies which include structural adaptations, antioxidant and photoprotective mechanisms, and the accumulation of proteins and metabolites that stabilise macromolecules. A full understanding of the phenomenon of vegetative desiccation tolerance will require a systems view of these adaptations at the levels of the genome, the control of gene expression, and the control of metabolic pathways. This dissertation reports a high-throughput metabolomic analysis of the changes that occur in vegetative tissues of resurrection plant Xerophyta humilis during dehydration. A combination of chromatography, mass spectrometry and nuclear magnetic resonance revealed numerous primary and secondary metabolites in the plant. Multivariate statistics identified a subset of metabolites that were significantly up- or down-regulated in response to water deficit stress. These metabolites both confirmed existing observations about the metabolic response of X. humilis to drying and revealed compounds not previously known to be associated with this response. Desiccation-associated metabolites were mapped onto known biochemical pathways, to generate hypotheses concerning possible regulatory schemes in the stress response, inviting deeper investigation in future.

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Casteriano, Andrea Veronica. "Physiological mechanisms of desiccation tolerance in Rhizobia." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/10423.

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One of the main factors affecting the survival of rhizobia on seed is desiccation stress. The poor survival of rhizobia affects nodulation, nitrogen fixation and legume yield. A better understanding of desiccation tolerance and how it may be enhanced may contribute to the development of strategies to improve survival of rhizobia on seed. This study aimed to improve the survival of rhizobia by enhancing inherent mechanisms of desiccation tolerance through the manipulation of the growth medium. Accumulation of intracellular trehalose by rhizobia increases in response to osmotic and desiccation stress, and has also been related to an improved capacity for desiccation tolerance. In this study, a linear relationship was observed between intracellular trehalose accumulation in Rhizobium leguminosarum bv. trifolii (TA1) and Bradyrhizobium japonicum (CB1809) and increasing osmotic pressure of a defined growth medium (JMM) from 1.0 atm to 2.8 atm. Although increased concentrations of intracellular trehalose did not improve survival of rhizobia immediately after vacuum drying, survival was significantly improved after 10 days of storage at low relative humidity (9%). Resuspending rhizobia in trehalose solution, to provide external protection to cells during drying, significantly increased survival immediately after drying and storage. The increased protection during drying allowed the positive effect of intracellular trehalose on rhizobial survival to be observed. Cells of TA1 and CB1809 extracted from peat after solid-state fermentation survived significantly better immediately after vacuum drying (22-fold and 5-fold respectively) and during storage than cells grown in JMM (1.0 atm). However, it was difficult to extract adequate V cell mass to measure intracellular trehalose and consequently cells were grown in water extracts of peat to simulate the conditions that rhizobia would be exposed to in traditional peat cultures. Growing TA1 and CB1809 in aqueous peat extract increased trehalose accumulation compared to cells grown in JMM and also significantly improved survival (18-fold) of TA1. Although survival of CB1809 was generally improved after growth in peat extract, it was not significantly different to cells grown in JMM. Cells grown in peat extract exhibited changes in cell morphology and protein expression similar to those observed after solid-state fermentation in peat. Electron microscopy revealed the accumulation of an electron-dense material around the plasma membrane that occupied the periplasmic space in both TA1 and CB1809. Similar changes to cell morphology have been previously linked to improved survival. Peptide analysis by liquid chromatography-mass spectrometry indicated increased expression of stress response proteins in TA1 and CB1809 after growth in peat extract. Some of those proteins included membrane repair proteins (PspA) and proteins generated to combat periplasmic stress (OstA) and oxidative damage (thioredoxin). A cell viability assay using alamarBlue® reagent showed that growing rhizobia in peat extract reduces metabolic activity compared to that of cells grown in JMM, and membrane integrity analysis of the same cells using a LIVE/DEAD® viability kit showed that peat extract increased membrane permeability to propidium iodide (PI). Environmental stresses have been reported to cause reversible changes to membrane function and permeability, demonstrated by changes in PI-uptake. This finding, together with the changes in cell morphology and increased expression of stress response proteins, suggests that improved survival after growth of rhizobia in peat extract is related to adaptive changes of cells in response to water-extractable constituents of peat. VI Findings from this work suggest that desiccation tolerance in rhizobia is a multifactorial process that involves the accumulation of trehalose together with the expression of proteins involved in maintaining cell envelope integrity and stability, as well as the repair and prevention of DNA and protein damage caused by oxidative stress. Determining chemical elicitors of adaptive changes in cells may assist in further development of inoculant technology to improve survival of rhizobia on seed.

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Mohammad, Noor. "Desiccation Cracking Behaviour in Thin Bentonite Layers." Thesis, The University of Sydney, 2020. https://hdl.handle.net/2123/22231.

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This thesis investigates the behaviour of desiccation cracks in thin bentonite layers under different conditions (initial water content, layer thickness, temperature and mixtures with kaolinite). For this, a comprehensive series of experiment was conducted as well as some theoretical models were developed. The theoretical model was developed based on the critical cracking thickness following the principles of linear elastic fracture mechanics (Chapter 4). This model was then used in the following chapters and validated with the experimental investigations. Also, hydraulic properties of the cracked soil mass were modelled and the effects of cracks on hydraulic conductivity and water retention properties were shown. In the experimental investigations, firstly, the combined effects of initial water content and layer thickness were studied in a phase diagram to observe the behaviour of desiccation cracks (Chapter 5). It was found that critical cracking thickness could be an important factor in distinguishing cracked and non-cracked samples in the phase diagram. Characteristics of cracks (crack density, total crack length, average crack length and crack width) increase with increasing layer thicknesses as well as initial water contents. The effects of temperature (Chapter 6) and mixtures of bentonite-kaolinite (Chapter 7) on desiccation cracking were investigated in the phase diagram developed in Chapter 5. At higher temperatures, the critical thickness of a clay layer ould be decreased. Results of bentonite-kaolinite mixture demonstrated that the phase boundary shifted to increase the critical thickness of the clay layers of mixtures containing less bentonite (i.e. more kaolinite). Crack morphology was also affected by the change in temperatures and properties of the mixtures. In summary, this study shows some understanding of desiccation cracking behaviour and could provide insights for better design of clay liners, which often at risk of desiccation problem.

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Fleming, Erich David. "Responses of desiccation-tolerant cyanobacteria to environmental extremes /." view abstract or download file of text, 2006. http://wwwlib.umi.com/cr/uoregon/fullcit?p3211215.

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Thesis (Ph. D.)--University of Oregon, 2006.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 115-129). Also available for download via the World Wide Web; free to University of Oregon users.

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Sheen, Tamsin, and n/a. "Osmotic and desiccation stress-tolerance of Serratia entomophila." University of Otago. Department of Microbiology & Immunology, 2008. http://adt.otago.ac.nz./public/adt-NZDU20081208.114925.

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Serratia entomophila, the causative agent of amber disease, is an endemic bacterium used for the biocontrol of New Zealand grass grub larvae. Although the available biopesticide is effective, its use is limited to areas where sub-surface application is feasible, and is also impacted by soil conditions such as moisture levels and osmolarity. The aim of this study was to elucidate the responses of S. entomophila to osmotic and desiccation stresses in relation to challenges encountered during production, storage and soil application, with the goal of developing a more robust and versatile biocontrol agent. RpoS is a key factor in the stress response of many enteric bacteria. In order to dissociate the effect of RpoS from subsequent cellular stress studies, an rpoS mutant was constructed by site-directed mutagenesis. Assessment of the rpoS mutant showed that RpoS was not implicated in NaC1 or desiccation tolerance of S. entomophila. The rpoS mutant was instead found to have enhanced salt tolerance and could be distinguished from the wild-type by the ability to ferment arabinose, a phenotype that was confirmed through complementation. Complete abolition of the amber disease process was observed using an rpoS strain also missing the Sep virulence genes, suggesting that RpoS is a regulator of the S. entomophila anti-feeding prophage (Afp). These findings indicate a subtle interplay between NaC1 tolerance, virulence and RpoS-mediated regulation of amber disease in S. entomophila. A transposon mutagenesis screen was carried out to identify genes associated with NaC1 tolerance in S. entomophila. Fourteen mutants displaying NaC1 sensitivity were identified, two of which had mutations in genes with potential implications for the formulation of the bacterium as a biocontrol agent. The gene leuO that encodes a LysR-family transcriptional regulator was found to be essential for S. entomophila NaC1 tolerance. The toxicity of increased cellular LeuO from an over-expression vector led to the investigation of the effects of leuO mutation on the proteome. Multiple protein changes observed by two-dimensional gel analysis suggested that LeuO may be a global regulator in S. entomophila, as has been hypothesised for Salmonella species. A second NaC1-sensitive mutant contained an insertion in afp15, the product of which is thought to be involved in assembly of the Afp. As well as being sensitive to NaC1, the afp15 mutant was unable to induce the anti-feeding component of amber disease, again highlighting the link between stress tolerance and virulence in S. entomophila. This study also determined that pre-exposure to NaC1 in conjunction with the provision of exogenous glycine betaine significantly enhanced the survival of S. entomophila either in a desiccated state or after application to soil, regardless of the soil moisture content. The implication of this finding on the future formulation of S. entomophila led to investigation of the underlying genetic mechanisms involved in glycine betaine synthesis and NaC1 tolerance. The genes involved in glycine betaine biosynthesis from choline were identified through genomic comparison, degenerate PCR and primer walking. A 6.5 kb region was sequenced and found to contain four genes with homology and similar chromosomal arrangement to the E. coli bet genes (betTIBA). The S. entomophila betIBA genes comprised an operon, flanked by the divergently-transcribed betT gene whose product is responsible for choline transport. To ascertain the relative transcription levels of components of the bet operon, quantitative RT-PCR was performed. Results of qRT-PCR showed that choline in conjunction with NaC1 induced the greatest levels of bet gene transcription, and that levels of the betA transcript were significantly lower than those of the other bet genes. Examination of the betA 5� non-coding region identified a previously undetected hairpin region, possibly accounting for the observed decrease in betA transcript levels. The findings of this study have significantly advanced our understanding of how S. entomophiia responds to stress, and will contribute to the development of formulation strategies for the production of a robust product capable of application to pasture by a range of teclmiques. In addition, there is significant potential to utilise these findings in the development of other bacterial inocula for a range of biotechnological applications.

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Books on the topic "Desiccation"

Jenks, Matthew A., and Andrew J. Wood, eds. Plant Desiccation Tolerance. Oxford, UK: Blackwell Publishing Ltd, 2007. http://dx.doi.org/10.1002/9780470376881.

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Lüttge, Ulrich, Erwin Beck, and Dorothea Bartels, eds. Plant Desiccation Tolerance. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-19106-0.

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Erwin, Beck, Bartels Dorothea, and SpringerLink (Online service), eds. Plant Desiccation Tolerance. Berlin, Heidelberg: Springer-Verlag Berlin Heidelberg, 2011.

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A, Jenks Matthew, and Wood Andrew J, eds. Plant desiccation tolerance. Ames, Iowa: Blackwell Pub., 2007.

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Establishment, Building Research, ed. Desiccation in clay soils. Watford: BRE, 1996.

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Goehring, Lucas, Akio Nakahara, Tapati Dutta, So Kitsunezaki, and Sujata Tarafdar. Desiccation Cracks and their Patterns. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2015. http://dx.doi.org/10.1002/9783527671922.

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Iwaya-Inoue, Mari, Minoru Sakurai, and Matsuo Uemura, eds. Survival Strategies in Extreme Cold and Desiccation. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-1244-1.

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Black, M., and H. W. Pritchard, eds. Desiccation and survival in plants: drying without dying. Wallingford: CABI, 2002. http://dx.doi.org/10.1079/9780851995342.0000.

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Michael, Black, and Pritchard H. W, eds. Desiccation and survival in plants: Drying without dying. Oxon, UK: CABI Pub., 2002.

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Gondwe, Dominic. Desiccation and storability of Syzygium cordatum (Hochst) seed. Zomba, Malawi: Malawi National Tree Seed Centre, Forestry Research Institute of Malawi, 2003.

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Book chapters on the topic "Desiccation"

Kodikara, Jayantha. "Desiccation." In Selective Neck Dissection for Oral Cancer, 1–3. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-12127-7_87-1.

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Horneck, Gerda. "Desiccation." In Encyclopedia of Astrobiology, 627–29. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-44185-5_416.

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Horneck, Gerda. "Desiccation." In Encyclopedia of Astrobiology, 420–22. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-11274-4_416.

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Mckersie, Bryan D., and Ya’acov Y. Leshem. "Desiccation." In Stress and Stress Coping in Cultivated Plants, 132–47. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-017-3093-8_6.

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Davenport, John. "Desiccation." In Environmental Stress and Behavioural Adaptation, 77–86. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-011-6073-5_5.

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Kodikara, Jayantha. "Desiccation." In Encyclopedia of Earth Sciences Series, 213–15. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-73568-9_87.

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Horneck, Gerda. "Desiccation." In Encyclopedia of Astrobiology, 1–3. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-27833-4_416-3.

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Bartels, Dorothea, Ulrich Lüttge, and Erwin Beck. "Introduction." In Plant Desiccation Tolerance, 3–8. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-19106-0_1.

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Steudle, Ernst. "Hydraulic Architecture of Vascular Plants." In Plant Desiccation Tolerance, 185–207. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-19106-0_10.

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Scheibe, Renate, and Erwin Beck. "Drought, Desiccation, and Oxidative Stress." In Plant Desiccation Tolerance, 209–31. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-19106-0_11.

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Conference papers on the topic "Desiccation"

Varsei, Maryam, Celine M. Bourasset, and Gerald A. Miller. "Laboratory Investigation of Desiccation Cracking." In Geo-Congress 2014. Reston, VA: American Society of Civil Engineers, 2014. http://dx.doi.org/10.1061/9780784413272.396.

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Malsam, Jason A., Vishard Ragoonanan, Daniel R. Bond, and Alptekin Aksan. "Desiccation Response of Geobacter sulfurreducens." In ASME 2007 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2007. http://dx.doi.org/10.1115/sbc2007-176271.

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Geobacter sulfurreducens is an electricity producing bacteria. It is used in bacterial fuel cells, microbial-based sensors, and catalytic surfaces for bioremediation. Further development of such applications requires stabilization and preservation of the bacteria as thin films on surfaces. This research investigated G.sulfurreducens response to desiccation to explore the feasibility of room temperature preservation. Room temperature preservation involves drying and storing bacteria at ambient conditions. Dried bacteria can be revived on demand by the addition of water.

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Oktay, A. B., N. B. Albayrak, and Y. S. Akgul. "Desiccation detection from lumbar MR images." In 2013 21st Signal Processing and Communications Applications Conference (SIU). IEEE, 2013. http://dx.doi.org/10.1109/siu.2013.6531433.

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Péron, H., L. Laloui, T. Hueckel, and L. Hu. "Experimental Study of Desiccation of Soil." In Fourth International Conference on Unsaturated Soils. Reston, VA: American Society of Civil Engineers, 2006. http://dx.doi.org/10.1061/40802(189)87.

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Martins, Natalia Pires, Burhan Cicek, Coralie Brumaud, and Guillaume Habert. "Self-Desiccation of a Vernacular CSA Binder." In 4th International Conference on Bio-Based Building Materials. Switzerland: Trans Tech Publications Ltd, 2022. http://dx.doi.org/10.4028/www.scientific.net/cta.1.339.

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The fast precipitation of ettringite in conventional Calcium Sulfo Aluminate (CSA) cement causes rapid stiffening of the cement paste and is directly associated with short setting times and self-desiccation. To extend the time during which those types of cement remain workable, retarding admixtures can be used. However, retarders may affect the amounts and types of hydration products formed and as a consequence the ability of hydrated cement to chemically bind water. This work investigates the influence of two natural-based admixtures on the self-desiccation ability of a vernacular CSA ternary binder used as earth stabilization. Vicat measurements were used to study the efficiency of citric acid and sucrose as retarding admixtures on the setting time of stabilized earth. A quantitative study of the self-desiccation ability of the binder was performed on dried binder pastes using thermogravimetric analysis (TGA). Results show that both admixtures have a significant impact on the setting time of the binder. Furthermore, TGA showed that the self-desiccation ability of this vernacular CSA binder is significantly reduced when citric acid at high dosages is used, both at early hydration and after 14 days. On the contrary, the use of sucrose does not affect the water chemically bound at an early age but can maximize bound water after 14 days of hydration.

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Wang, Fujun, Vanessa Gallardo, Stephen Michielsen, and Tiegang Fang. "Poster: Controlling desiccation pattern through droplet impacting." In 72th Annual Meeting of the APS Division of Fluid Dynamics. American Physical Society, 2019. http://dx.doi.org/10.1103/aps.dfd.2019.gfm.p0029.

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Yang, Rui, Jinsong Huang, D. V. Griffiths, and Daichao Sheng. "Effects of Desiccation Cracks on Slope Reliability." In Proceedings of the 7th International Symposium on Geotechnical Safety and Risk (ISGSR 2019). Singapore: Research Publishing Services, 2019. http://dx.doi.org/10.3850/978-981-11-2725-0-is9-13-cd.

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Burkhart, Collin T., Peter D. Dunning, and Michael J. Schertzer. "Electrowetting on Dielectric (EWOD) Assisted Droplet Desiccation." In ASME 2015 13th International Conference on Nanochannels, Microchannels, and Minichannels collocated with the ASME 2015 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/icnmm2015-48498.

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Lab-on-a-chip (LOAC) devices are emerging technologies that aim to perform all of the laboratory functions of traditional diagnostic tests on single microchips. Microarrays are one promising type of LOAC device that consist of an array of droplets for testing tens to thousands of samples simultaneously. Microarrays are commonly used in gene sequencing, pathogen detection, determining microbial resistances, and conducting enzyme-linked immunosorbent assays (ELISAs). As droplets in these arrays dry, the majority of material within the droplet is deposited around the periphery. This phenomenon is referred to as the coffee stain effect. The non-uniform depositions left by this effect can result in variation of fluorescence intensity measurements in automated vision systems. A means of producing more uniform particle depositions for the microscopy analysis would allow for more accurate test results. One promising method for suppression of the coffee stain effect involves the use of electrowetting on dielectric (EWOD). EWOD devices apply an electrokinetic force at the three-phase contact line to manipulate the shape of a droplet interface. The Mugele group has already begun investigating EWOD’s effects on the coffee stain effect and found that an AC voltage applied to droplets on EWOD devices can suppress the coffee stain effect and produce smaller, more uniform droplet deposition patterns. This work presents (i) a method to characterize the deposition pattern left by a desiccated droplet as a function of radial position and (ii) a discussion of the microfabrication technique used to create devices to perform EWOD assisted desiccation for both AC and DC voltages.

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Chaduvula, Uma, B. V. S. Viswanadham, and Jayantha Kodikara. "Desiccation Cracking Behavior of Geofiber-Reinforced Expansive Clay." In Geo-Chicago 2016. Reston, VA: American Society of Civil Engineers, 2016. http://dx.doi.org/10.1061/9780784480144.036.

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Hu, LiangBo, Hervé Péron, Tomasz Hueckel, and Lyesse Laloui. "Numerical and Phenomenological Study of Desiccation of Soil." In GeoShanghai International Conference 2006. Reston, VA: American Society of Civil Engineers, 2006. http://dx.doi.org/10.1061/40860(192)17.

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Reports on the topic "Desiccation"

Daniele Armaleo, Daniele Armaleo. How do lichens withstand desiccation? Experiment, December 2018. http://dx.doi.org/10.18258/12505.

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Sela, Shlomo, and Michael McClelland. Desiccation Tolerance in Salmonella and its Implications. United States Department of Agriculture, May 2013. http://dx.doi.org/10.32747/2013.7594389.bard.

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Salmonella enterica is a worldwide food-borne pathogen, which regularly causes large outbreaks of food poisoning. Recent outbreaks linked to consumption of contaminated foods with low water-activity, have raised interest in understanding the factors that control fitness of this pathogen to dry environment. Consequently, the general objective of this study was to extend our knowledge on desiccation tolerance and long-term persistence of Salmonella. We discovered that dehydrated STm entered into a viable-but-nonculturable state, and that addition of chloramphenicol reduced bacterial survival. This finding implied that adaptation to desiccation stress requires de-novo protein synthesis. We also discovered that dried STm cells develop cross-tolerance to multiple stresses that the pathogen might encounter in the agriculture/food environment, such as high or low temperatures, salt, and various disinfectants. These findings have important implications for food safety because they demonstrate the limitations of chemical and physical treatments currently utilized by the food industry to completely inactivate Salmonella. In order to identify genes involved in desiccation stress tolerance, we employed transcriptomic analysis of dehydrated and wet cells and direct screening of knock-out mutant and transposon libraries. Transcriptomic analysis revealed that dehydration induced expression of ninety genes and down-regulated seven. Ribosomal structural genes represented the most abundant functional group with a relatively higher transcription during dehydration. Other large classes of induced functional groups included genes involved in amino acid metabolism, energy production, ion transport, transcription, and stress response. Initial genetic analysis of a number of up-regulated genes was carried out). It was found that mutations in rpoS, yahO, aceA, nifU, rpoE, ddg,fnr and kdpE significantly compromised desiccation tolerance, supporting their role in desiccation stress response.

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BENECKE MW. STANDARDS CONTROLLING AIR EMISSIONS FOR THE SOIL DESICCATION PILOT TEST. Office of Scientific and Technical Information (OSTI), September 2010. http://dx.doi.org/10.2172/1004073.

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Kirchhoff, Helmut, and Ziv Reich. Protection of the photosynthetic apparatus during desiccation in resurrection plants. United States Department of Agriculture, February 2014. http://dx.doi.org/10.32747/2014.7699861.bard.

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In this project, we studied the photosynthetic apparatus during dehydration and rehydration of the homoiochlorophyllous resurrection plant Craterostigmapumilum (retains most of the photosynthetic components during desiccation). Resurrection plants have the remarkable capability to withstand desiccation, being able to revive after prolonged severe water deficit in a few days upon rehydration. Homoiochlorophyllous resurrection plants are very efficient in protecting the photosynthetic machinery against damage by reactive oxygen production under drought. The main purpose of this BARD project was to unravel these largely unknown protection strategies for C. pumilum. In detail, the specific objectives were: (1) To determine the distribution and local organization of photosynthetic protein complexes and formation of inverted hexagonal phases within the thylakoid membranes at different dehydration/rehydration states. (2) To determine the 3D structure and characterize the geometry, topology, and mechanics of the thylakoid network at the different states. (3) Generation of molecular models for thylakoids at the different states and study the implications for diffusion within the thylakoid lumen. (4) Characterization of inter-system electron transport, quantum efficiencies, photosystem antenna sizes and distribution, NPQ, and photoinhibition at different hydration states. (5) Measuring the partition of photosynthetic reducing equivalents between the Calvin cycle, photorespiration, and the water-water cycle. At the beginning of the project, we decided to use C. pumilum instead of C. wilmsii because the former species was available from our collaborator Dr. Farrant. In addition to the original two dehydration states (40 relative water content=RWC and 5% RWC), we characterized a third state (15-20%) because some interesting changes occurs at this RWC. Furthermore, it was not possible to detect D1 protein levels by Western blot analysis because antibodies against other higher plants failed to detect D1 in C. pumilum. We developed growth conditions that allow reproducible generation of different dehydration and rehydration states for C. pumilum. Furthermore, advanced spectroscopy and microscopy for C. pumilum were established to obtain a detailed picture of structural and functional changes of the photosynthetic apparatus in different hydrated states. Main findings of our study are: 1. Anthocyan accumulation during desiccation alleviates the light pressure within the leaves (Fig. 1). 2. During desiccation, stomatal closure leads to drastic reductions in CO2 fixation and photorespiration. We could not identify alternative electron sinks as a solution to reduce ROS production. 3. On the supramolecular level, semicrystalline protein arrays were identified in thylakoid membranes in the desiccated state (see Fig. 3). On the electron transport level, a specific series of shut downs occur (summarized in Fig. 2). The main events include: Early shutdown of the ATPase activity, cessation of electron transport between cyt. bf complex and PSI (can reduce ROS formation at PSI); at higher dehydration levels uncoupling of LHCII from PSII and cessation of electron flow from PSII accompanied by crystal formation. The later could severe as a swift PSII reservoir during rehydration. The specific order of events in the course of dehydration and rehydration discovered in this project is indicative for regulated structural transitions specifically realized in resurrection plants. This detailed knowledge can serve as an interesting starting point for rationale genetic engineering of drought-tolerant crops.

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Gaugler, Randy, Itamar Glazer, Daniel Segal, and Sarwar Hashmi. Molecular Approach for Improving the Stability of Insecticidal Nematodes. United States Department of Agriculture, November 2002. http://dx.doi.org/10.32747/2002.7580680.bard.

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Our overall goal is to improve insecticidal nematodes by genetically engineering strains capable of entering an enhanced state of dormancy that provides improved stability. Objectives: 1. Clone and sequence tps-l homologue from Steinernema carpocapsae. (Revised: A failure to isolate the tps gene group from Steinernema precipitated a redirection to identifying other genes involved in insecticidal nematode desiccation process.) 2. Incorporate cloned tps-l gene into S. carpocapsae to obtain overexpression, thereby, enhancing desiccation tolerance. (Revised: Other stress genes in addition to tps-l genes were cloned and efforts at expression in S. carpocapsae were conducted) 3. Characterize the transgenic strains. No other biological control agent offers more impressive attributes than insecticidal nematodes. However, their potential is limited by the bane of nearly all biological control agents: poor stability. This leads to inadequate shelf-life and ultimately reduced field efficacy. Nematode storage is based on desiccation, yet insecticidal species are only capable of partial desiccation termed quiescent anhydrobiosis. Overwhelming evidence has shown that when the disaccharide compound trehalose is elevated in anhydrobiotic organisms such as yeast, plants, and nematodes it enables these organisms the ability to survive environmental stresses i.e., desiccation. Armed with this information our goal was to improve insecticidal nematodes stability by engineering trehalose overexpression.

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Sela, Shlomo, and Michael McClelland. Investigation of a new mechanism of desiccation-stress tolerance in Salmonella. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7598155.bard.

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Low-moisture foods (LMF) are increasingly involved in foodborne illness. While bacteria cannot grow in LMF due to the low water content, pathogens such as Salmonella can still survive in dry foods and pose health risks to consumer. We recently found that Salmonella secretes a proteinaceous compound during desiccation, which we identified as OsmY, an osmotic stress response protein of 177 amino acids. To elucidate the role of OsmY in conferring tolerance against desiccation and other stresses in Salmonella entericaserovarTyphimurium (STm), our specific objectives were: (1) Characterize the involvement of OsmY in desiccation tolerance; (2) Perform structure-function analysis of OsmY; (3) Study OsmY expression under various growth- and environmental conditions of relevance to agriculture; (4) Examine the involvement of OsmY in response to other stresses of relevance to agriculture; and (5) Elucidate regulatory pathways involved in controlling osmY expression. We demonstrated that an osmY-mutant strain is impaired in both desiccation tolerance (DT) and in long-term persistence during cold storage (LTP). Genetic complementation and addition of a recombinantOsmY (rOsmY) restored the mutant survival back to that of the wild type (wt). To analyze the function of specific domains we have generated a recombinantOsmY (rOsmY) protein. A dose-response DT study showed that rOsmY has the highest protection at a concentration of 0.5 nM. This effect was protein- specific as a comparable amount of bovine serum albumin, an unrelated protein, had a three-time lower protection level. Further characterization of OsmY revealed that the protein has a surfactant activity and is involved in swarming motility. OsmY was shown to facilitate biofilm formation during dehydration but not during bacterial growth under optimal growth conditions. This finding suggests that expression and secretion of OsmY under stress conditions was potentially associated with facilitating biofilm production. OsmY contains two conserved BON domains. To better understand the role of the BON sites in OsmY-mediated dehydration tolerance, we have generated two additional rOsmY constructs, lacking either BON1 or BON2 sites. BON1-minus (but not BON2) protein has decreased dehydration tolerance compared to intact rOsmY, suggesting that BON1 is required for maximal OsmY-mediated activity. Addition of BON1-peptide at concentration below 0.4 µM did not affect STm survival. Interestingly, a toxic effect of BON1 peptide was observed in concentration as low as 0.4 µM. Higher concentrations resulted in complete abrogation of the rOsmY effect, supporting the notion that BON-mediated interaction is essential for rOsmY activity. We performed extensive analysis of RNA expression of STm undergoing desiccation after exponential and stationary growth, identifying all categories of genes that are differentially expressed during this process. We also performed massively in-parallel screening of all genes in which mutation caused changes in fitness during drying, identifying over 400 such genes, which are now undergoing confirmation. As expected OsmY is one of these genes. In conclusion, this is the first study to identify that OsmY protein secreted during dehydration contributes to desiccation tolerance in Salmonella by facilitating dehydration- mediated biofilm formation. Expression of OsmY also enhances swarming motility, apparently through its surfactant activity. The BON1 domain is required for full OsmY activity, demonstrating a potential intervention to reduce pathogen survival in food processing. Expression and fitness screens have begun to elucidate the processes of desiccation, with the potential to uncover additional specific targets for efforts to mitigate pathogen survival in desiccation.

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Alam, Todd M., Brian Ray Cherry, and Mary Kathleen Alam. Relaxation nuclear magnetic resonance imaging (R-NMRI) of desiccation in M9787 silicone pads. Office of Scientific and Technical Information (OSTI), June 2004. http://dx.doi.org/10.2172/919111.

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Truex, Michael J., Martinus Oostrom, Vicky L. Freedman, Christopher E. Strickland, Thomas W. Wietsma, Guzel D. Tartakovsky, and Anderson L. Ward. Laboratory and Modeling Evaluations in Support of Field Testing for Desiccation at the Hanford Site. Office of Scientific and Technical Information (OSTI), February 2011. http://dx.doi.org/10.2172/1009749.

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Truex, Michael J., Martinus Oostrom, Christopher E. Strickland, Timothy C. Johnson, Vicky L. Freedman, Christian D. Johnson, William J. Greenwood, et al. Deep Vadose Zone Treatability Test for the Hanford Central Plateau: Soil Desiccation Pilot Test Results. Office of Scientific and Technical Information (OSTI), May 2012. http://dx.doi.org/10.2172/1095466.

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Truex, Michael J., Martinus Oostrom, Christopher E. Strickland, Timothy C. Johnson, Christian D. Johnson, Ray E. Clayton, and Glen B. Chronister. Deep Vadose Zone Treatability Test for the Hanford Central Plateau: Interim Post-Desiccation Monitoring Results. Office of Scientific and Technical Information (OSTI), September 2013. http://dx.doi.org/10.2172/1170500.

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