00852nas a2200229 4500008004100000022001400041245008800055210006900143260007700212300001200289490000600301653002000307653002300327653001700350653001800367653001800385100002200403700002400425700002800449700003000477856011500507 2013 eng d a1861-472800aInfluence of the sophorolipid molecular geometry on their self-assembled structures0 aInfluence of the sophorolipid molecular geometry on their selfas aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcFEB a369-3720 v810abolaamphiphiles10ahelical structures10ap-p stacking10aSelf-assembly10asophorolipids1 aDhasaiyan, Prabhu1 aBanerjee, Agnimitra1 aVisaveliya, Nikunjkumar1 aPrasad, Bhagavatula L. V. uhttps://library.ncl.res.in/content/influence-sophorolipid-molecular-geometry-their-self-assembled-structures-000985nas a2200181 4500008004100000022001400041245006300055210006200118260011000180300001600290490000600306520029600312100003100608700002200639700003000661700002100691856009100712 2014 eng d a2046-206900aAccess to harmonine, a chemical weapon of ladybird beetles0 aAccess to harmonine a chemical weapon of ladybird beetles aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJUL a30923-309260 v43 a

The synthesis of harmonine, a defense alkaloid from the harlequin ladybird is reported by three different routes. The preparation of several new analogs with the same molecular weight and the decoration of gold nanoparticles with harmonines are also part of the present communication.

1 aPhilkhana, Satish, Chandra1 aDhasaiyan, Prabhu1 aPrasad, Bhagavatula L. V.1 aReddy, Srinivasa uhttps://library.ncl.res.in/content/access-harmonine-chemical-weapon-ladybird-beetles-001674nas a2200253 4500008004100000022001400041245017700055210006900232260007700301300001400378490000700392520068600399653002001085653001901105653001801124653001801142653001301160100002201173700002501195700002801220700001501248700003001263856012701293 2014 eng d a0947-653900aVesicle structures from bolaamphiphilic biosurfactants: experimental and molecular dynamics simulation studies on the effect of unsaturation on sophorolipid self-assemblies0 aVesicle structures from bolaamphiphilic biosurfactants experimen aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcMAY a6246-62500 v203 a

The formation of giant-vesicle-like structures by self-assembling linolenic acid sophorolipid (LNSL) molecules is revealed. Sophorolipids belong to the class of bolaamphiphilic glycolipid biosurfactants. Interestingly, the number of double bonds present in the hydrophobic core of sophorolipids is seen to have a great influence on the type of self-assembled structures formed. Dye encapsulation results establish the presence of an aqueous compartment inside the LNSL vesicles. Molecular dynamics simulation (MD) studies suggest the existence of two possible conformations of LNSLs inside the self-assembled structures and that LNSL molecules arrange in layered structures.

10abolaamphiphiles10aMD simulations10aSelf-assembly10asophorolipids10avesicles1 aDhasaiyan, Prabhu1 aPandey, Prithvi, Raj1 aVisaveliya, Nikunjkumar1 aRoy, Sudip1 aPrasad, Bhagavatula L. V. uhttps://library.ncl.res.in/content/vesicle-structures-bolaamphiphilic-biosurfactants-experimental-and-molecular-dynamics-001049nas a2200205 4500008004100000022001400041245010300055210006900158260000800227300001700235490000600252520031500258100002200573700002000595700002400615700001800639700002500657700003000682856013100712 2016 eng d a2046-206900aSelf- assembly of isomannide-based monoesters of C18-fatty acids and their cellular uptake studies0 aSelf assembly of isomannidebased monoesters of C18fatty acids an cJUL a 72074-720790 v63 a

The self-assembling behavior of oleic, elaidic and stearic acid-isomannide glycolipids is revealed. Amongst these, oleic and elaidic acid-based isomannide lipids self-assembled to form microspheres which were efficiently taken up by cancer cell lines enabling their usage for drug delivery applications.

1 aDhasaiyan, Prabhu1 aParekh, Nimisha1 aReddy, Vijai, Kumar1 aRani, Sandhya1 aDevi, B., L. A. Prab1 aPrasad, Bhagavatula L. V. uhttps://library.ncl.res.in/content/self-assembly-isomannide-based-monoesters-c18-fatty-acids-and-their-cellular-uptake-studies01831nas a2200229 4500008004100000022001400041245009800055210006900153260007900222300001200301490000800313520098400321653001801305653001801323653001801341653002801359100002501387700002201412700003001434700001501464856012201479 2016 eng d a0942-935200aStructural insight into self assembly of sophorolipids: a molecular dynamics simulation study0 aStructural insight into self assembly of sophorolipids a molecul aGENTHINER STRASSE 13, D-10785 BERLIN, GERMANYbWALTER DE GRUYTER GMBHcMAY a819-8360 v2303 a

Sophorolipids contain hydrophilic head groups at the ends of a long hydrophobic tail. As a result, sophorolipids can self assemble into variety of structures in water. Atomistic self assembly simulations of sophorolipids are performed in water. Two sophorolipids, oleic acid sophorolipid and linolenic acid sophorolipid, differing in number of double bonds in the hydrophobic tail are considered for this study. Long time self assembly simulations are performed considering 1 :3 lipid to water ratio by weight for both oleic and linolenic acid sophorolipids. In addition to 1 : 3 ratio, long time self assembly simulations are also performed with 1 : 1 and 1 : 2 ratios for linolenic acid sophorolipids. Distinctions in structural arrangements of sophorolipid molecules in the self assembled configuration for all the systems are investigated. The present study aims to provide structural insight into the different self assembled configurations of sophorolipids in water.

10aMD Simulation10aself assembly10asophorolipids10aUnited Atom Force Field1 aPandey, Prithvi, Raj1 aDhasaiyan, Prabhu1 aPrasad, Bhagavatula L. V.1 aRoy, Sudip uhttps://library.ncl.res.in/content/structural-insight-self-assembly-sophorolipids-molecular-dynamics-simulation-study01998nas a2200205 4500008004100000245010500041210006900146260000800215300001200223520123300235100002201468700002201490700002101512700001801533700002901551700003101580700003101611700001801642856013201660 2017 eng d00aMicelles versus Ribbons: how congeners drive the self-assembly of acidic sophorolipid biosurfactants0 aMicelles versus Ribbons how congeners drive the selfassembly of  cMAR a643-6523 a

Sophorolipids (SLs), a class of microbially derived biosurfactants, are reported by different research groups to have different self-assembled structures (either micelles or giant ribbons) under the same conditions. Here we explore the reasons behind these contradictory results and attribute these differences to the role of specific congeners that are present in minute quantities. We show that a sample composed of a majority of oleic acid (C18:1) sophorolipid in the presence of only 0.5 % (or more) of congeners with stearic acid (C18:0) or linoleic acid (C18:2) results in the formation of micelles that are stable over long periods of time. Conversely, the presence of only 10 to 15 % of congeners with a stearic acid chain gives fibrillar structures instead of micelles. To study the mechanisms responsible, oleic acid SLs devoid of any other congeners were prepared. Very interestingly, this sample can self-assemble into either micelles or fibers depending on minute modifications to the self-assembly conditions. The findings are supported by light scattering, small-angle X-ray scattering, transmission electron microscopy under cryogenic conditions, high-pressure liquid chromatography, and NMR spectroscopy.

1 aDhasaiyan, Prabhu1 aLe Griel, Patrick1 aRoelants, Sophie1 aRedant, Emile1 aVan Bogaert, Inge, N. A.1 aPrevost, Sylvain, Francois1 aPrasad, Bhagavatula, L. V.1 aBaccile, Niki uhttps://library.ncl.res.in/content/micelles-versus-ribbons-how-congeners-drive-self-assembly-acidic-sophorolipid-biosurfactants02669nas a2200169 4500008004100000022001400041245005100055210004900106260000800155300000900163490000700172520212100179653006602300100002202366700003002388856008102418 2017 eng d a1527-899900aSelf - assemblies of bolaamphiphilic molecules0 aSelf assemblies of bolaamphiphilic molecules cNOV a1-150 v173 a

The current buzzword in science and technology is self-assembly and molecular self-assembly is one of the most prominent fields as far as research in chemical and biological sciences is concerned. Generally, self-assembly of molecules occurs through weak non-covalent interactions like hydrogen bonding, π–π stacking, hydrophobic effects, etc. Inspired by many natural systems consisting of self-assembled structures, scientists have been trying to understand their formation and mimic such processes in the laboratory to create functional “smart” materials, which respond to temperature, light, pH, electromagnetic field, mechanical stress, and/or chemical stimuli. These responses are usually manifested as remarkable changes from the molecular (e. g., conformational state, hierarchical order) to the macroscopic level (e. g., shape, surface properties). Many molecules such as peptides, viruses, and surfactants are known to self-assemble into different structures. Among them, glycolipids are the new entries in the area of molecules that are being investigated for their self-assembly characteristics. Among the different classes of glycolipids like rhamnolipids and trehalose lipids, owing to their biological preparations and their structural novelty, sophorolipids (SLs) are evoking greater interest among researchers. Sophorolipids are a class of asymmetric bolas bearing COOH groups at one end and sophorose (dimeric glucose linked by an unusual β(1→2) linkage). The extreme membrane stability of Archaea, attributed to the membrane-spanning bolas (tetraether glycolipids), has inspired chemists to unravel the molecular designs that underpin the self-assembly of bolaamphiphilic molecules. Apart from these self-assembled structures, bolaamphiphiles find applications in many fields such as drug delivery, membrane mimicking, siRNA therapies, etc. The first part of this Personal Account presents some possible self-assembled structures of bolaamphiphiles and their mechanism of formation. The later part covers our work on one of the typical bolaamphiphiles known as sophorolipids.

10aBolaamphiphiles; gels; self-assembly; sophorolipids; vesicles1 aDhasaiyan, Prabhu1 aPrasad, Bhagavatula L. V. uhttps://library.ncl.res.in/content/self-assemblies-bolaamphiphilic-molecules01792nas a2200181 4500008004100000022001400041245011600055210006900171260000900240300001400249490000700263520112100270100002201391700002101413700001801434700003101452856012701483 2018 eng d a0743-746300apH- and time-resolved in situ SAXS study of self-assembled twisted ribbons formed by elaidic acid sophorolipids0 apH and timeresolved in situ SAXS study of selfassembled twisted  cFEB  a2121-21310 v343 a

Conditions that favor the helical structure formation in structurally similar sophorolipids (SLs), that is, elaidic acid SLs (having a trans double bond between the C9 and C10 positions of the alkyl chain) and stearic acid SLs (no double bond), are presented here. The helical self-assembled structures formed by elaidic acid SLs were independent of pH and also were mediated by a micellar intermediate. On the other hand, the stearic acid SLs formed helical structures under low pH condition only. Astonishingly, the formation routes were found to be different, albeit the molecular geometry of both SLs is similar. Even if a conclusive mechanistic understanding must await further work, our studies strongly point out that the noncovalent weak interactions in elaidic acid SLs are able to overcome the electrostatic repulsions of the sophorolipid carboxylate groups at basic pH and facilitating the formation of helical structures. On the other hand, the hydrophobic interactions in stearic acid SLs endow the helical structures with extra stability, making them less vulnerable to dissolution upon heating.

1 aDhasaiyan, Prabhu1 aPrevost, Sylvain1 aBaccile, Niki1 aPrasad, Bhagavatula, L. V. uhttps://library.ncl.res.in/content/ph-and-time-resolved-situ-saxs-study-self-assembled-twisted-ribbons-formed-elaidic-acid02124nas a2200265 4500008004100000022001400041245015100055210006900206260000800275300001400283490000600297520118300303100002201486700003101508700002201539700001901561700002201580700001801602700002001620700002601640700002401666700001801690700002101708856012901729 2020 eng d a2058-968900aAntibacterial properties of glycosylated surfaces: variation of the glucosidal moiety and fatty acid conformation of grafted microbial glycolipids0 aAntibacterial properties of glycosylated surfaces variation of t cAUG a1307-13160 v53 a

Glycosylated surfaces can display antimicrobial properties. It has been shown that sophorolipids can be used to develop biocidal coatings against Gram-positive and Gram-negative bacteria, but with a limited efficiency so far. Therefore, it appears necessary to further investigate the surface antibacterial activity of a broader set of structurally related glycolipids. The present work explores the influence of the glucosidic moiety (gluco-, sophoro-, cellobio-) and the fatty acid backbone (saturated,cisortransmonounsaturated). We show that the fatty acid backbone plays an important role:cisderivative of sophorolipids (SL) grafted onto model gold surfaces has better biocidal properties than saturated (SL0) andtransmonounsaturated (SLt) molecules, which appear to be inefficient. The number of glucose units is also a key factor: a one-third decrease in antibacterial activity is observed when having one glucose unit (GL) compared to two (SL). Sugar acetylation (SLa) does not seem to have an impact on the biocidal properties of surfaces. These results are not limited to sophorolipids, with cellobioselipids (CL) leading to similar antibacterial observations.

1 aValotteau, Claire1 aRoelants, Sophie, L. K. V.1 aDhasaiyan, Prabhu1 aZibek, Susanne1 aGuenther, Michael1 aSoetaert, Wim1 aEveraert, Bernd1 aPradier, Claire-Marie1 aBabonneau, Florence1 aBaccile, Niki1 aHumblot, Vincent uhttps://library.ncl.res.in/content/antibacterial-properties-glycosylated-surfaces-variation-glucosidal-moiety-and-fatty-acid