The role of hopanoids in fortifying rhizobia against a changing climate

Tookmanian, Elise M.; Belin, Brittany J; Sáenz, James; Newman, Dianne K.

doi:10.1111/1462-2920.15594

Cited by 21 publications

(26 citation statements)

References 99 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This symbiosis is a very close interaction, with the bacteria living intracellularly in specialized de novo organs called root nodules. Low pH, low oxygen, and elevated osmolarity are maintained within the nodule environment (7)(8)(9). While in some ways stressful for the bacteria, this environment favors bacterial conversion of nitrogen gas to bioavailable ammonia which eventually is exchanged for reduced carbon in the form of dicarboxylic acids.…”

Section: Introductionmentioning

confidence: 99%

Hopanoids Confer Robustness to Physicochemical Variability in the Niche of the Plant Symbiont Bradyrhizobium diazoefficiens

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Introductionmentioning

confidence: 99%

Hopanoids Confer Robustness to Physicochemical Variability in the Niche of the Plant Symbiont Bradyrhizobium diazoefficiens

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…In response to the above challenges, the organisms adopt different strategies to maintain membrane structure and functions in various odds. One of the key strategies is the homeoviscous adaptation, − which protects the cell membrane from the cold stress by tuning the saturated/unsaturated fatty acid composition. Enhanced synthesis of osmolytes, small organic polar molecules, is another well-known adaptive strategy. ,, Sugars, dimethyl sulfoxide, glycerol, trehalose, urea, TMAO, and so on are some of the osmolytes which can minimize the effect of osmotic stress. − Certain plants produce fructans to protect cell membranes against drying .…”

Section: Introductionmentioning

confidence: 99%

How Do Urea and Trimethylamine N-Oxide Influence the Dehydration-Induced Phase Transition of a Lipid Membrane?

Maiti

Daschakraborty

2021

J. Phys. Chem. B

View full text Add to dashboard Cite

Living organisms are often exposed to extreme dehydration, which is detrimental to the structure and function of the cell membrane. The lipid membrane undergoes fluid-to-gel phase transition due to dehydration and thus loses fluidity and functionality. To protect the fluid phase of the bilayer these organisms adopt several strategies. Enhanced production of small polar organic solutes (also called osmolytes) is one such strategy. Urea and trimethylamine N-oxide (TMAO) are two osmolytes found in different organisms combating osmotic stress. Previous experiments have found that both these osmolytes have strong effects on lipid membrane under different hydration conditions. Urea prevents the dehydration-induced phase transition of the lipid membrane by directly interacting with the lipids, while TMAO does not inhibit the phase transition. To provide atomistic insights, we have carried out all-atom molecular dynamics (MD) simulation of a lipid membrane under varying hydration levels and studied the effect of these osmolytes on different structural and dynamic properties of the membrane. This study suggests that urea significantly inhibits the dehydration-induced fluid-to-gel phase transition by strongly interacting with the lipid membrane via hydrogen bonds, which balances the reduced lipid hydration due to the decreasing water content. In contrast, TMAO is excluded from the membrane surface due to unfavorable interaction with the lipids. This induces further dehydration of the lipids which reinforces the fluid-to-gel phase transition. We have also studied the counteractive role of TMAO on the effect of urea on lipid membrane when both the osmolytes are present. TMAO draws some urea molecules out of the membrane and thereby reduces the effect of urea on the lipid membrane at lower hydration levels. This is similar to the counteraction of urea's deleterious ef fects on protein by TMAO. All these observations are consistent with the experimental results and thus provide deep molecular insights into the role of these osmolytes in protecting the fluid phase of the membrane, the key survival strategy against osmotic-stress-induced dehydration.

show abstract

“…21 They were also proposed as important molecules for adaptation to a changing climate. 22 Starting from hopene (HOP), elongated hopanoids can be synthesized. 23 HOP, which is nearly always found in trace amounts in hopanoid-producing bacteria, 24 is an interesting molecule in lipid research because it lacks polar head groups (see the chemical structure in Figure 1A).…”

Section: ■ Introductionmentioning

confidence: 99%

“…Besides, the microorganisms displayed an increased sensitivity to extreme pHs, detergents, and various antibiotics. , In addition to their role in stress tolerance, hopanoids are important for nutrient storage, and have been proposed as general environmental stress biomarkers . They were also proposed as important molecules for adaptation to a changing climate …”

Section: Introductionmentioning

confidence: 99%

Hopanoid Hopene Locates in the Interior of Membranes and Affects Their Properties

2021

View full text Add to dashboard Cite

Hopanoids are proposed as sterol surrogates in some bacteria, and it has been proved that some hopanoids are able to induce a liquid-order phase state in lipid membranes. The members of this group of molecules have diverse structures, and not all of them have been studied in detail yet. Here, we study membranes with the hopanoid hopene (hop-22 (29)-ene or diploptene), which is the product of the cycling of squalene by squalene–hopene cyclase, and thus is present in the first step of hopanoid biosynthesis. Hopene is particularly interesting because it lacks a polar head group, which opens the question of how does this molecule accommodate in a lipid membrane, and what are the effects promoted by its presence. In order to get an insight into this, we prepared monolayers and bilayers of a phospholipid with hopene and studied their properties in comparison with pure phospholipid membranes, and with the sterol cholesterol or the hopanoid diplopterol. Film stiffness, shear viscosity, and bending dynamics were very affected by the presence of hopene, while zeta-potential, generalized polarization of Laurdan, and conductivity were affected moderately by this molecule. The results suggest that at very low percentages, hopene locates parallel to the phospholipid molecules, while the excess of the hopene molecules stays between leaflets, as previously proposed using molecular dynamics simulations.

show abstract

The role of hopanoids in fortifying rhizobia against a changing climate

Cited by 21 publications

References 99 publications

Hopanoids Confer Robustness to Physicochemical Variability in the Niche of the Plant Symbiont Bradyrhizobium diazoefficiens

Hopanoids Confer Robustness to Physicochemical Variability in the Niche of the Plant Symbiont Bradyrhizobium diazoefficiens

How Do Urea and Trimethylamine N-Oxide Influence the Dehydration-Induced Phase Transition of a Lipid Membrane?

Hopanoid Hopene Locates in the Interior of Membranes and Affects Their Properties

Contact Info

Product

Resources

About