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Dianne K Newman - One of the best experts on this subject based on the ideXlab platform.
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extended Hopanoid loss reduces bacterial motility and surface attachment and leads to heterogeneity in root nodule growth kinetics in a bradyrhizobium aeschynomene symbiosis
Molecular Plant-microbe Interactions, 2019Co-Authors: Brittany J Belin, E T Tookmanian, J De Anda, Gerard C L Wong, Dianne K NewmanAbstract:Hopanoids are steroid-like bacterial lipids that enhance membrane rigidity and promote bacterial growth under diverse stresses. Roughly 10% of bacteria contain genes involved in Hopanoid biosynthesis, and these genes are particularly conserved in plant-associated organisms. We previously found that the extended class of Hopanoids (C35) in the nitrogen-fixing soil bacterium Bradyrhizobium diazoefficiens promotes its root nodule symbiosis with the tropical legume Aeschynomene afraspera. By quantitatively modeling root nodule development, we identify independent consequences of extended Hopanoid loss in the initiation of root nodule formation and in the rate of root nodule maturation. In vitro studies demonstrate that extended Hopanoids support B. diazoefficiens motility and surface attachment, which may correlate with stable root colonization in planta. Confocal microscopy of maturing root nodules reveals that root nodules infected with extended Hopanoid-deficient B. diazoefficiens contain unusually low densities of bacterial symbionts, indicating that extended Hopanoids are necessary for persistent, high levels of host infection.
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extended Hopanoid loss reduces bacterial motility and surface attachment and leads to heterogeneity in root nodule growth kinetics in a bradyrhizobium aeschynomene symbiosis
Molecular Plant-microbe Interactions, 2019Co-Authors: Brittany J Belin, E T Tookmanian, J De Anda, Gerard C L Wong, Dianne K NewmanAbstract:Hopanoids are steroid-like bacterial lipids that enhance membrane rigidity and promote bacterial growth under diverse stresses. Hopanoid biosynthesis genes are conserved in nitrogen-fixing plant symbionts, and we previously found that the extended (C35) class of Hopanoids in Bradyrhizobium diazoefficiens are required for efficient symbiotic nitrogen fixation in the tropical legume host Aeschynomene afraspera. Here, we demonstrate that the nitrogen-fixation defect conferred by extended Hopanoid loss can be fully explained by a reduction in root nodule sizes rather than per-bacteroid nitrogen-fixation levels. Using a single-nodule tracking approach to quantify A. afraspera nodule development, we provide a quantitative model of root nodule development in this host, uncovering both the baseline growth parameters for wild-type nodules and a surprising heterogeneity of extended Hopanoid mutant developmental phenotypes. These phenotypes include a delay in root nodule initiation and the presence of a subpopulation of nodules with slow growth rates and low final volumes, which are correlated with reduced motility and surface attachment in vitro and lower bacteroid densities in planta, respectively. This work provides a quantitative reference point for understanding the phenotypic diversity of ineffective symbionts in A. afraspera and identifies specific developmental stages affected by extended Hopanoid loss for future mechanistic work.
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extended Hopanoid loss reduces bacterial motility and surface attachment and leads to heterogeneity in root nodule growth kinetics in a bradyrhizobium aeschynomene symbiosis
bioRxiv, 2018Co-Authors: Brittany J Belin, E T Tookmanian, J De Anda, Gerard C L Wong, Dianne K NewmanAbstract:Abstract Hopanoids are steroid-like bacterial lipids that enhance membrane rigidity and promote bacterial growth under diverse stresses. Hopanoid biosynthesis genes are conserved in nitrogen-fixing plant symbionts, and we previously found that the extended (C35) class of Hopanoids in Bradyrhizobium diazoefficiens are required for efficient symbiotic nitrogen fixation in the tropical legume host Aeschynomene afraspera. Here we demonstrate that the nitrogen fixation defect conferred by extended loss can fully be explained by a reduction in root nodule sizes rather than per-bacteroid nitrogen fixation levels. Using a single-nodule tracking approach to track A. afraspera nodule development, we provide a quantitative model of root nodule development in this host, uncovering both the baseline growth parameters for wild-type nodules and a surprising heterogeneity of extended Hopanoid mutant developmental phenotypes. These phenotypes include a delay in root nodule initiation and presence of a subpopulation of nodules with slow growth rates and low final volumes, which are correlated with reduced motility and surface attachment in vitro and lower bacteroid densities in planta, respectively. This work provides a quantitative reference point for understanding the phenotypic diversity of ineffective symbionts in A. afraspera and identifies specific developmental stages affected by extended Hopanoid loss for future mechanistic work.
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extended Hopanoid lipids promote bacterial motility surface attachment and root nodule development in the bradyrhizobium diazoefficiens aeschynomene afraspera symbiosis
bioRxiv, 2018Co-Authors: Brittany J Belin, E T Tookmanian, J De Anda, Gerard C L Wong, Dianne K NewmanAbstract:Hopanoids are steroid-like bacterial lipids that enhance membrane rigidity and promote bacterial growth under diverse stresses. Roughly 10% of bacteria contain genes involved in Hopanoid biosynthesis, and these genes are particularly conserved in plant-associated organisms. We previously found that the extended class of Hopanoids (C35) in the nitrogen-fixing soil bacterium Bradyrhizobium diazoefficiens promotes its root nodule symbiosis with the tropical legume Aeschynomene afraspera. By quantitatively modeling root nodule development, we identify independent roles for Hopanoids in the initiation of root nodule formation and in determining the rate of root nodule maturation. In vitro studies demonstrate that extended Hopanoids support B. diazoefficiens motility and surface attachment, which may correlate with stable root colonization in planta. Confocal microscopy of maturing root nodules reveals that root nodules infected with extended Hopanoid-deficient B. diazoefficiens contain unusually low densities of bacterial symbionts, indicating that extended Hopanoids are necessary for persistent, high levels of host infection. This work identifies extended Hopanoids as regulators of the efficiency of Bradyrhizobia nitrogen-fixing symbioses, agriculturally and economically significant associations with growing importance in a changing climate.
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Hopanoid lipids from membranes to plant bacteria interactions
Nature Reviews Microbiology, 2018Co-Authors: Brittany J Belin, Alba Silipo, Nicolas Busset, Antonio Molinaro, Eric Giraud, Dianne K NewmanAbstract:Lipid research represents a frontier for microbiology, as showcased by Hopanoid lipids. Hopanoids, which resemble sterols and are found in the membranes of diverse bacteria, have left an extensive molecular fossil record. They were first discovered by petroleum geologists. Today, Hopanoid-producing bacteria remain abundant in various ecosystems, such as the rhizosphere. Recently, great progress has been made in our understanding of Hopanoid biosynthesis, facilitated in part by technical advances in lipid identification and quantification. A variety of genetically tractable, Hopanoid-producing bacteria have been cultured, and tools to manipulate Hopanoid biosynthesis and detect Hopanoids are improving. However, we still have much to learn regarding how Hopanoid production is regulated, how Hopanoids act biophysically and biochemically, and how their production affects bacterial interactions with other organisms, such as plants. The study of Hopanoids thus offers rich opportunities for discovery.
Brittany J Belin - One of the best experts on this subject based on the ideXlab platform.
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extended Hopanoid loss reduces bacterial motility and surface attachment and leads to heterogeneity in root nodule growth kinetics in a bradyrhizobium aeschynomene symbiosis
Molecular Plant-microbe Interactions, 2019Co-Authors: Brittany J Belin, E T Tookmanian, J De Anda, Gerard C L Wong, Dianne K NewmanAbstract:Hopanoids are steroid-like bacterial lipids that enhance membrane rigidity and promote bacterial growth under diverse stresses. Roughly 10% of bacteria contain genes involved in Hopanoid biosynthesis, and these genes are particularly conserved in plant-associated organisms. We previously found that the extended class of Hopanoids (C35) in the nitrogen-fixing soil bacterium Bradyrhizobium diazoefficiens promotes its root nodule symbiosis with the tropical legume Aeschynomene afraspera. By quantitatively modeling root nodule development, we identify independent consequences of extended Hopanoid loss in the initiation of root nodule formation and in the rate of root nodule maturation. In vitro studies demonstrate that extended Hopanoids support B. diazoefficiens motility and surface attachment, which may correlate with stable root colonization in planta. Confocal microscopy of maturing root nodules reveals that root nodules infected with extended Hopanoid-deficient B. diazoefficiens contain unusually low densities of bacterial symbionts, indicating that extended Hopanoids are necessary for persistent, high levels of host infection.
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extended Hopanoid loss reduces bacterial motility and surface attachment and leads to heterogeneity in root nodule growth kinetics in a bradyrhizobium aeschynomene symbiosis
Molecular Plant-microbe Interactions, 2019Co-Authors: Brittany J Belin, E T Tookmanian, J De Anda, Gerard C L Wong, Dianne K NewmanAbstract:Hopanoids are steroid-like bacterial lipids that enhance membrane rigidity and promote bacterial growth under diverse stresses. Hopanoid biosynthesis genes are conserved in nitrogen-fixing plant symbionts, and we previously found that the extended (C35) class of Hopanoids in Bradyrhizobium diazoefficiens are required for efficient symbiotic nitrogen fixation in the tropical legume host Aeschynomene afraspera. Here, we demonstrate that the nitrogen-fixation defect conferred by extended Hopanoid loss can be fully explained by a reduction in root nodule sizes rather than per-bacteroid nitrogen-fixation levels. Using a single-nodule tracking approach to quantify A. afraspera nodule development, we provide a quantitative model of root nodule development in this host, uncovering both the baseline growth parameters for wild-type nodules and a surprising heterogeneity of extended Hopanoid mutant developmental phenotypes. These phenotypes include a delay in root nodule initiation and the presence of a subpopulation of nodules with slow growth rates and low final volumes, which are correlated with reduced motility and surface attachment in vitro and lower bacteroid densities in planta, respectively. This work provides a quantitative reference point for understanding the phenotypic diversity of ineffective symbionts in A. afraspera and identifies specific developmental stages affected by extended Hopanoid loss for future mechanistic work.
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extended Hopanoid loss reduces bacterial motility and surface attachment and leads to heterogeneity in root nodule growth kinetics in a bradyrhizobium aeschynomene symbiosis
bioRxiv, 2018Co-Authors: Brittany J Belin, E T Tookmanian, J De Anda, Gerard C L Wong, Dianne K NewmanAbstract:Abstract Hopanoids are steroid-like bacterial lipids that enhance membrane rigidity and promote bacterial growth under diverse stresses. Hopanoid biosynthesis genes are conserved in nitrogen-fixing plant symbionts, and we previously found that the extended (C35) class of Hopanoids in Bradyrhizobium diazoefficiens are required for efficient symbiotic nitrogen fixation in the tropical legume host Aeschynomene afraspera. Here we demonstrate that the nitrogen fixation defect conferred by extended loss can fully be explained by a reduction in root nodule sizes rather than per-bacteroid nitrogen fixation levels. Using a single-nodule tracking approach to track A. afraspera nodule development, we provide a quantitative model of root nodule development in this host, uncovering both the baseline growth parameters for wild-type nodules and a surprising heterogeneity of extended Hopanoid mutant developmental phenotypes. These phenotypes include a delay in root nodule initiation and presence of a subpopulation of nodules with slow growth rates and low final volumes, which are correlated with reduced motility and surface attachment in vitro and lower bacteroid densities in planta, respectively. This work provides a quantitative reference point for understanding the phenotypic diversity of ineffective symbionts in A. afraspera and identifies specific developmental stages affected by extended Hopanoid loss for future mechanistic work.
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extended Hopanoid lipids promote bacterial motility surface attachment and root nodule development in the bradyrhizobium diazoefficiens aeschynomene afraspera symbiosis
bioRxiv, 2018Co-Authors: Brittany J Belin, E T Tookmanian, J De Anda, Gerard C L Wong, Dianne K NewmanAbstract:Hopanoids are steroid-like bacterial lipids that enhance membrane rigidity and promote bacterial growth under diverse stresses. Roughly 10% of bacteria contain genes involved in Hopanoid biosynthesis, and these genes are particularly conserved in plant-associated organisms. We previously found that the extended class of Hopanoids (C35) in the nitrogen-fixing soil bacterium Bradyrhizobium diazoefficiens promotes its root nodule symbiosis with the tropical legume Aeschynomene afraspera. By quantitatively modeling root nodule development, we identify independent roles for Hopanoids in the initiation of root nodule formation and in determining the rate of root nodule maturation. In vitro studies demonstrate that extended Hopanoids support B. diazoefficiens motility and surface attachment, which may correlate with stable root colonization in planta. Confocal microscopy of maturing root nodules reveals that root nodules infected with extended Hopanoid-deficient B. diazoefficiens contain unusually low densities of bacterial symbionts, indicating that extended Hopanoids are necessary for persistent, high levels of host infection. This work identifies extended Hopanoids as regulators of the efficiency of Bradyrhizobia nitrogen-fixing symbioses, agriculturally and economically significant associations with growing importance in a changing climate.
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Hopanoid lipids from membranes to plant bacteria interactions
Nature Reviews Microbiology, 2018Co-Authors: Brittany J Belin, Alba Silipo, Nicolas Busset, Antonio Molinaro, Eric Giraud, Dianne K NewmanAbstract:Lipid research represents a frontier for microbiology, as showcased by Hopanoid lipids. Hopanoids, which resemble sterols and are found in the membranes of diverse bacteria, have left an extensive molecular fossil record. They were first discovered by petroleum geologists. Today, Hopanoid-producing bacteria remain abundant in various ecosystems, such as the rhizosphere. Recently, great progress has been made in our understanding of Hopanoid biosynthesis, facilitated in part by technical advances in lipid identification and quantification. A variety of genetically tractable, Hopanoid-producing bacteria have been cultured, and tools to manipulate Hopanoid biosynthesis and detect Hopanoids are improving. However, we still have much to learn regarding how Hopanoid production is regulated, how Hopanoids act biophysically and biochemically, and how their production affects bacterial interactions with other organisms, such as plants. The study of Hopanoids thus offers rich opportunities for discovery.
Michel Rohmer - One of the best experts on this subject based on the ideXlab platform.
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identification and mode of formation of Hopanoid nitriles in archaeological soils
Organic Geochemistry, 2016Co-Authors: Pierre Adam, Philippe Schaeffer, Gaby Schmitt, Lucile Bailly, Blandine Courel, Margaux Fresnais, Carole Fossurier, Michel RohmerAbstract:Abstract In the course of investigation of lipid extracts from archaeological soils from two Merovingian tombs (7th Century, Ichtratzheim, France) in an agricultural area, a series of N-containing Hopanoids was detected. They were postulated to correspond to C 31 –C 33 Hopanoid nitriles on the basis of mass spectrometry. The C 32 homologue was unambiguously identified by comparison with a standard obtained by synthesis. The mode of formation of the compounds was investigated using laboratory simulation experiments involving either N -acetyl-aminobacteriohopanetriol as a model compound representative of bacterial Hopanoids with polyfunctionalized side chains, or C 32 hopan-32-al. The experiments led us to propose that the formation of the nitriles from C 35 bioHopanoid polyols could result from a two step process involving initially an oxidation step leading to the shortening of the functionalized side chain and a second step during which N is incorporated. In the context of the soils containing archaeological wood remains from tombs and found in an agricultural area, oxidants would certainly be available, notably in the form of O 2 diffusing from the surface or H 2 O 2 produced during wood degradation by wood-rotting fungi. Possible N sources could be residual N from the decomposing body within the tomb or manure and fertilizers used for field amendment. The laboratory experiments also gave a better insight into the diagenetic processes leading to the side chain shortening of the Hopanoids. In particular, it could be shown that C 31 Hopanoids also derive from tetrafunctionalized Hopanoids upon diagenesis and not solely from pentafunctionalized Hopanoids as generally suggested in the literature.
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ribosylhopane a novel bacterial Hopanoid as precursor of c35 bacteriohopanepolyols in streptomyces coelicolor a3 2
ChemBioChem, 2014Co-Authors: Wenjun Liu, Elmar L. Kannenberg, Thomas Härtner, Helen M Talbot, Elias Sakr, Philippe Schaeffer, Janina Donisi, Eriko Takano, Michel RohmerAbstract:Wild-type Streptomyces coelicolor A3(2) produces aminobacteriohopanetriol as the only elongated C35 Hopanoid. The Hopanoid phenotype of two mutants bearing a deletion of genes from a previously identified Hopanoid biosynthesis gene cluster provides clues to the formation of C35 bacteriohopanepolyols. orf14 encodes a putative nucleosidase; its deletion induces the accumulation of adenosylhopane as it cannot be converted into ribosylhopane. orf18 encodes a putative transaminase; its deletion results in the accumulation of adenosylhopane, ribosylhopane, and bacteriohopanetetrol. Ribosylhopane was postulated twenty years ago as a precursor for bacterial Hopanoids but was never identified in a bacterium. Absence of the transaminase encoded by orf18 prevents the reductive amination of ribosylhopane into aminobacteriohopanetriol and induces its accumulation. Its reduction by an aldose-reductase-like enzyme produces bacteriohopanetetrol, which is normally not present in S. coelicolor.
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high Hopanoid total lipids ratio in frankia mycelia is not related to the nitrogen status
Microbiology, 2000Co-Authors: Renaud Nalin, Surya Rosa Putra, Michel Rohmer, Annemarie Domenach, Francois Gourbiere, Alison M BerryAbstract:Vesicles are specific Frankia structures which are produced under nitrogenlimiting culture conditions. Hopanoids are the most abundant lipids in these vesicles and are believed to protect the nitrogenase against oxygen. The amounts and quality of each Hopanoid were estimated in different Frankia strains cultivated under nitrogen-depleted and nitrogen-replete conditions in order to detect a possible variation. Studied Frankia strains nodulating Eleagnus were phylogenetically characterized by analysis of the nifD‐K intergenic region as closely related to genomic species 4 and 5. Phylogenetically different strains belonging to three infectivity groups were cultivated in the same medium with and without nitrogen source for 10 d before Hopanoid content analysis by HPLC. Four Hopanoids together accounted for 23‐87% and 15‐87% of the total lipids under nitrogen-replete and nitrogen-depleted culture conditions, respectively. Two of the Hopanoids found, bacteriohopanetetrols and their phenylacetic acid esters, have previously been described in Frankia. Two new Hopanoids, moretan-29-ol and a bacteriohopanetetrol propionate, have also been identified. The moretan-29-ol and bacteriohopanetetrols were found to be the most abundant Hopanoids whereas the bacteriohopanetetrol propionate and phenylacetates were present at a concentration close to the limit of detection. The ratio of (bacteriohopanetetrolsM moretan-29-ol)/(total lipids) varied in most of the strains between nitrogen-depleted and nitrogen-replete culture conditions. In most of the strains, the Hopanoid content was found to be slightly higher under nitrogen-replete conditions than under nitrogen-depleted conditions. These results suggest that remobilization, rather than neosynthesis of Hopanoids, is implicated in vesicle formation in Frankia under nitrogendepleted conditions.
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bacterial triterpenoids of the hopane series as biomarkers for the chemotaxonomy of burkholderia pseudomonas and ralstonia spp
Fems Microbiology Letters, 2000Co-Authors: Jelena H Cvejic, Surya Rosa Putra, Adel Elbeltagy, Reiko Hattori, Tsutomu Hattori, Michel RohmerAbstract:Hopanoid fingerprints allowed to differentiate bacteria formerly connected to the genus Pseudomonas. Whereas all strains related to Pseudomonas and Ralstonia were devoid of any detectable Hopanoid, these pentacyclic triterpenoids were found in the Burkholderia species and in related soil isolates, which contained as main Hopanoid a bacteriohopanetetrol carbapseudopentose ether, accompanied by significant amounts of its novel Δ6 unsaturated homologue. Unsaturated Hopanoids represent an extremely rare feature in soil bacteria and the only known indication for a catabolism of this pentacyclic carbon skeleton in bacteria.
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bacterial triterpenoids of the hopane series from the methanotrophic bacteria methylocaldum spp phylogenetic implications and first evidence for an unsaturated aminobacteriohopanepolyol
Fems Microbiology Letters, 2000Co-Authors: Jelena H Cvejic, Levente Bodrossy, Kornel L Kovacs, Michel RohmerAbstract:The Hopanoid content of the two methanotrophic bacteria Methylocaldum szegediense and Methylocaldum tepidum was investigated. 35-Aminobacteriohopane-30R,31R,32R,33S,34S-pentol and its 3β-methyl homologue were present in both strains. In M. tepidum, they were accompanied by 35-aminobacteriohopane-31R,32R,33S,34S-tetrol and its 3β-methyl homologue. The side chain structure was identical to those previously reported from two other obligate methanotrophs, Methylococcus capsulatus and Methylomonas methanica. The two Methylocaldum species shared with the Methylococcus species the presence of 3β-methylHopanoid as well as of a Hopanoid releasing adiantol upon H5IO6/NaBH4 treatment. A rare feature was in addition found in M. szegediense. The saturated Hopanoids were accompanied by an unsaturated aminobacteriohopanepentol with a Δ11 double bond. Comparison of the Hopanoid fingerprints was in accordance with the close phylogenetic relationship of Methylococcus and Methylocaldum. The major difference was the absence of sterols in Methylocaldum which were always detected in the Methylococcus species.
Surya Rosa Putra - One of the best experts on this subject based on the ideXlab platform.
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analisis genus dan Hopanoid dari isolatmurni bakteri tanah hutan pinus
Master Theses Chemistry RTKi 572.84 Har a 2008, 2009Co-Authors: Surya Rosa PutraAbstract:Hopanoid merupakan senyawa triterpen pentasiklik yang terdapat pada bakteri. Distribusi senyawa Hopanoid banyak ditemukan pada kelompok bakteri tanah. Senyawa Hopanoid telah berhasil diidentifikasi dari kultur murni campuran bakteri tanah dan kemungkinan berasal dari kontribusi kelompok bakteri penyubur tanah. Pada penelitian ini, dilakukan identifikasi senyawa Hopanoid dari genus yang terkait, isolat murni bakteri tanah hutan pinus. Hopanoid diperoleh dengan cara ekstraksi sel kering dengan kloroform/metanol (2:1 v/v) dan didegradasi dengan H5IO6/NaBH4 , KK fraksinasi, asetilasi dengan asetat/piridin, dan analisis menggunakan KG-MS. Penentuan genus bakteri tanah meliputi pewarnaan Gram, pewarnaan kapsula, pewarnaan endospora, respirasi bakteri, bentuk sel, ukuran sel dan gerak bakteri. Selain itu digunakan analisa microbact system untuk penentuan genus. Hasil dari penelitian ini diidentifikasi 3 genus yaitu Clostridium, Bacillus dan Klebsiella dari 4 isolat murni bakteri tanah hutan pinus. Masing-masing genus tersebut memproduksi senyawa Hopanoid yang khas. 17β(H),21β(H)-homohop- 30-ol-31-asetat khas untuk Clostridium. Metil-hop-6(7),17(21)-dien dan 17β(H),21β(H)-metil hopan khas untuk Bacillus. Sedangkan metil-hop- 6(7),17(21)-dien, 17β(H),21β(H)-bishomohop-30-ol-32-asetat, 17β(H),21β(H)- metilhomohop-6-en-30-ol-31-asetat dan hop-17(22)en-35-asetat khas untuk Klebsiella. Kekhasan struktur Hopanoid yang diperoleh memberikan indikasi bahwa senyawa Hopanoid bisa digunakan sebagai marker keanekaragaman jenis bakteri penyubur tanah dalam suatu habitat tanah. Selain itu senyawa ini bisa digunakan sebagai indikator kesuburan tanah.
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ANALISIS KANDUNGAN Hopanoid DAN ASAM LEMAK DALAM Clostridium perfringens DAN Streptomyces sp
2009Co-Authors: Surya Rosa PutraAbstract:Clostridium perfringens dan Streptomyces sp merupakan bakteri penyerap nitrogen untuk kesuburan tanah. Tetapi keberadaan kedua bakteri tersebut sangat sulit dilacak. Hopanoid adalah molekul yang berperan penting untuk menemukan keberadaan kedua bakteri tersebut, terutama Hopanoid yang spesifik dapat dijadikan marker. Untuk membuktikannya, maka dilakukan analisis kandungan Hopanoid pada kedua bakteri tersebut dengan mengekstrak lipid total dari sel keringnya dengan pelarut kloroform/methanol (2;1,v/v), degradasi menggunakan H5IO6/NaBH4, fraksinasi Kromatografi Kolom (KK) dan Asetilasi dengan Ac2O/piridin. Hopanoid dianalisis dengan Kromatografi Gas-Spektroskopi Massa (KG-SM). Berat sel kering dari Clostridium perfringens dan Streptomyces sp adalah 0,78 g dan 1,85 g, sedangkan berat lipid totalnya adalah 89,74 mg/ g sel kering dan 129,73 mg/ g sel kering. Fraksi Hopanoid dari Clostridium perfringens dan Streptomyces sp secara berturut-turut adalah 4,87 mg/ g sel kering (5,43 %) dan 7,03 mg/ g sel kering (5,42 %). Sedangkan fraksi asam lemak dari Clostridium perfringens dan Streptomyces sp adalah 5,00 mg/ g sel kering (5,60 %) dan 7,14 mg/ g sel kering (5,50 %). Clostridium perfringens dan Streptomyces sp menghasilkan bis-homohopan 30,32-diol asetat. Senyawa yang diidentifikasi dari puncak dominan adalah 1-heptadekanol asetat. Adanya fragmen m/z 191 dan m/z 369 pada puncak 33 (tR = 29,76), 39 (tR = 37,39), 40 (tR = 41,22) untuk Clostridium perfringens dan pada puncak 42 (tR = 37,61), 43 (tR = 43,13) untuk Streptomyces sp membuktikan bahwa Clostridium perfringens dan Streptomyces sp mengandung Hopanoid jenis bakteriohopanpoliol. Asam lemak yang dihasilkan Clostridium perfringens dan Streptomyces sp adalah asam heptadekanoat etil ester, asam heksadekanoat etil ester dan asam pentadekanoat etil ester.
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analisis kandungan Hopanoid dan asam lemak dalam bacillus pumilus
Undergraduate Theses Chemistry RSKi 572 Pal a 2007, 2009Co-Authors: Surya Rosa PutraAbstract:Asam lemak dan Hopanoid yang terdapat dalam lipid mikroorganisme dapat dimanfaatkan sebagai marker dalam kemotaksonomi. Untuk menguatkan dugaan itu keberadaan asam lemak dan Hopanoid dalam Bacillus pumilus sebagai bakteri pelarut fosfat perlu diteliti. Kandungan Hopanoid dalam sel kering bakteri diekstraksi dengan pelarut kloroform/metanol (2:1, v/v), degradasi dengan H5IO6/NaBH4, fraksinasi Kromatografi Kolom (KK) dan asetilasi dengan Ac2O/piridin. Hopanoid dianalisis dengan Kromatografi Gas-Spektroskopi Massa (KG-SM). Sel kering yang diperoleh sebanyak 1045,20 mg/l, lipid total yang diperoleh 0,12 mg/mg sel kering. Fraksi Hopanoid dan asam lemak setelah asetilasi secara berturut turut adalah 1,60 mg dan 1,63 mg. Senyawa yang diidentifikasi dari puncak dominan adalah 1-heptadekanol asetat. Adanya fragmen m/z 191 dan m/z 369 pada puncak dan 42 membuktikan bahwa Bacillus pumilus mengandung Hopanoid jenis bakteriohopanpoliol. Asam lemak yang dihasilkan Bacillus pumilus adalah asam heptadekanoat etil ester, asam heksadekanoat etil ester dan asam asam pentadekanoat etil ester.
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analisis Hopanoid pada sinorhizobium fredii
Master thesis Chemistry Departement RTKi 579.3 Ang a 2008, 2009Co-Authors: Surya Rosa PutraAbstract:Analisis kandungan Hopanoid dari beberapa bakteri merupakan langkah eksperimen untuk membuktikan dugaan bahwa Hopanoid dapat dijadikan marker dalam kemotaksonomi. Keberadaan Hopanoid dalam Sinorhizobium fredii yaitu suatu bakteri fiksasi nitrogen yang hidup dalam tanah perlu diteliti,untuk mencari hubungan kekerabatan antara bakteri penyubur tanah. Kandungan Hopanoid kompleks dalam sel kering diekstrak dengan pelarut kloroform/methanol ( 2;1, v/v ). Oksidasi dan reduksi Hopanoid menggunakan pelarut asam periodat dan natrium boro hidrida. Asetilasi Hopanoid menggunakan pelarut piridin/ asetat anhidrat (1:1, v/v ).Langkah akhir Hopanoid terasetilasi dideteksi menggunakan Kromatograf Gas- Spektroskopi Massa (KG-SM). Keberadaan fragmen-fragmen spesifik m/z = 73, 191, 295, dan 369 membuktikan bahwa Sinorhizobium fredii mengandung Hopanoid bis- homohopan 31, 32 - diol Asetat
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analisis kandungan Hopanoid pada tanahperkebunan desa sambiroto nganjuk
Undergraduate thesis Chemistry Departement RSKi 572.84 Wid a 2008, 2009Co-Authors: Surya Rosa PutraAbstract:Bakteri merupakan kelompok mikroorganisme paling dominan dalam tanah. Salah satu bakteri tanah adalah bakteri penyerap nitrogen yang mengandung Hopanoid. Hopanoid merupakan senyawa metabolit sekunder golongan terpena. Analisis Hopanoid pada tanah dapat menunjukkan adanya korelasi antara kandungan Hopanoid dengan jenis tanah. Penelitian ini mengambil cuplikan tanah dari perkebunan desa Sambiroto Nganjuk pada kedalaman ± 30 cm.Kemudian diekstrak dengan metode sokhletasi menggunakan pelarut kloroform/metanol (2:1). Ekstrak lipid tanah yang diperoleh kemudian didegradasi dengan metode H5IO6/NaBH4. Analisis kromatografi gas – spektroskopi massa (KG – SM) digunakan untuk menentukan jenis Hopanoid dan asam lemak dari fraksi Hopanoid yang terdapat dalam tanah. Akan tetapi, spektrum massa dari penelitian menunjukkan fragmen spesifik Hopanoid (m/z 191 dan 263) dengan kelimpahan yang relatif kecil, sehingga kemungkinan Hopanoid dalam tanah tersebut merupakan senyawa minor. Senyawa yang terdeteksi adalah asam lemak, yaitu : etil palmitat (0,005 mg/g cuplikan tanah) dan etil cerotat (0,018 mg/g cuplikan tanah).
Roger E. Summons - One of the best experts on this subject based on the ideXlab platform.
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elucidation of the burkholderia cenocepacia Hopanoid biosynthesis pathway uncovers functions for conserved proteins in Hopanoid producing bacteria
Environmental Microbiology, 2015Co-Authors: Crystal L Schmerk, Roger E. Summons, Paula V Welander, Mohamad A Hamad, Katie Bain, Mark A Bernards, Miguel A ValvanoAbstract:Summary Hopanoids are bacterial surrogates of eukaryotic membrane sterols and among earth's most abundant natural products. Their molecular fossils remain in sediments spanning more than a billion years. However, Hopanoid metabolism and function are not fully understood. Burkholderia species are environmental opportunistic pathogens that produce Hopanoids and also occupy diverse ecological niches. We investigated Hopanoids biosynthesis in Burkholderia cenocepacia by deletion mutagenesis and structural characterization of the Hopanoids produced by the mutants. The enzymes encoded by hpnH and hpnG were essential for production of all C35 extended Hopanoids, including bacteriohopanetetrol (BHT), BHT glucosamine and BHT cyclitol ether. Deletion of hpnI resulted in BHT production, while ΔhpnJ produced only BHT glucosamine. Thus, HpnI is required for BHT glucosamine production while HpnJ is responsible for its conversion to the cyclitol ether. The ΔhpnH and ΔhpnG mutants could not grow under any stress condition tested, whereas ΔhpnI, ΔhpnJ and ΔhpnK displayed wild-type growth rates when exposed to detergent, but varying levels of sensitivity to low pH and polymyxin B. This study not only elucidates the biosynthetic pathway of Hopanoids in B. cenocepacia, but also uncovers a biosynthetic role for the conserved proteins HpnI, HpnJ and HpnK in other Hopanoid-producing bacteria.
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identification and characterization of rhodopseudomonas palustris tie 1 Hopanoid biosynthesis mutants
Geobiology, 2012Co-Authors: Paula V Welander, Roger E. Summons, Dianne K Newman, David M Doughty, S MehayAbstract:Hopanes preserved in both modern and ancient sediments are recognized as the molecular fossils of bacteriohopanepolyols, pentacyclic Hopanoid lipids. Based on the phylogenetic distribution of Hopanoid production by extant bacteria, hopanes have been used as indicators of specific bacterial groups and/or their metabolisms. However, our ability to interpret them ultimately depends on understanding the physiological roles of Hopanoids in modern bacteria. Toward this end, we set out to identify genes required for Hopanoid biosynthesis in the anoxygenic phototroph Rhodopseudomonas palustris TIE-1 to enable selective control of Hopanoid production. We attempted to delete 17 genes within a putative Hopanoid biosynthetic gene cluster to determine their role, if any, in Hopanoid biosynthesis. Two genes, hpnH and hpnG, are required to produce both bacteriohopanetetrol and aminobacteriohopanetriol, whereas a third gene, hpnO, is required only for aminobacteriohopanetriol production. None of the genes in this cluster are required to exclusively synthesize bacteriohopanetetrol, indicating that at least one other Hopanoid biosynthesis gene is located elsewhere on the chromosome. Physiological studies with the different deletion mutants demonstrated that unmethylated and C_30 Hopanoids are sufficient to maintain cytoplasmic but not outer membrane integrity. These results imply that Hopanoid modifications, including methylation of the A-ring and the addition of a polar head group, may have biologic functions beyond playing a role in membrane permeability.
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new constraints on the provenance of Hopanoids in the marine geologic record bacteriohopanepolyols in marine suboxic and anoxic environments
Organic Geochemistry, 2011Co-Authors: James P Saenz, Stuart G Wakeham, Timothy I Eglinton, Roger E. SummonsAbstract:Abstract The abundance and structural diversity of bacteriohopanepolyols (BHPs) was examined in three marine pelagic environments that are characterized by strong vertical redox gradients and water column suboxia or anoxia. The abundance and, in most instances, structural diversity of BHPs was highest at depths where conditions were suboxic or anoxic. However, the majority of the BHP structures that were identified are environmentally cosmopolitan and their biological sources are presently not well constrained. An isomer of bacteriohopanetetrol (denoted BHT II) was observed at all three study sites in association with anoxic and suboxic conditions within the water column. Based on the absence of BHT II from terrigenous and oxic marine environments studied to date, and its strong association with suboxic and anoxic marine pelagic environments, we propose that BHT II is a promising candidate biomarker for water column suboxia and anoxia in the marine geologic record. The molecular fingerprint of BHPs in suspended and sinking particles and core-top sediments indicates that Hopanoids produced within the water column are exported to marine sediments and that their biological source is most likely associated with settling particles and not the free-water phase. Based on our observations, BHPs likely represent an important input to the sedimentary Hopanoid inventory, particularly in upwelling environments characterized by pelagic oxygen minimum zones (OMZ) and anoxic marine basins.
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the rnd family transporter hpnn is required for Hopanoid localization to the outer membrane of rhodopseudomonas palustris tie 1
Proceedings of the National Academy of Sciences of the United States of America, 2011Co-Authors: David M Doughty, Roger E. Summons, Ryan C Hunter, Alex L Sessions, Maureen L Coleman, Dianne K NewmanAbstract:Rhodopseudomonas palustris TIE-1 is a Gram-negative bacterium that produces structurally diverse Hopanoid lipids that are similar to eukaryotic steroids. Its genome encodes several homologues to proteins involved in eukaryotic steroid trafficking. In this study, we explored the possibility that two of these proteins are involved in intracellular Hopanoid transport. R. palustris has a sophisticated membrane system comprising outer, cytoplasmic, and inner cytoplasmic membranes. It also divides asymmetrically, producing a mother and swarmer cell. We deleted genes encoding two putative Hopanoid transporters that belong to the resistance–nodulation– cell division superfamily. Phenotypic analyses revealed that one of these putative transporters (HpnN) is essential for the movement of Hopanoids from the cytoplasmic to the outer membrane, whereas the other (Rpal_4267) plays a minor role. C30 Hopanoids, such as diploptene, are evenly distributed between mother and swarmer cells, whereas hpnN is required for the C35 Hopanoid, bacteriohopanetetrol, to remain localized to the mother cell type. Mutant cells lacking HpnN grow like the WT at 30 °C but slower at 38 °C. Following cell division at 38 °C, the ΔhpnN cells remain connected by their cell wall, forming long filaments. This phenotype may be attributed to Hopanoid mislocalization because a double mutant deficient in both Hopanoid biosynthesis and transport does not form filaments. However, the lack of Hopanoids severely compromises cell growth at higher temperatures more generally. Because Hopanoid mutants only manifest a strong phenotype under certain conditions, R. palustris is an attractive model organism in which to study their transport and function.
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2 methylHopanoids are maximally produced in akinetes of nostoc punctiforme geobiological implications
Geobiology, 2009Co-Authors: David M Doughty, Roger E. Summons, Ryan C Hunter, Dianne K NewmanAbstract:2-Methylhopanes, molecular fossils of 2-methylbacteriohopanepolyol (2-MeBHP) lipids, have been proposed as biomarkers for cyanobacteria, and by extension, oxygenic photosynthesis. However, the robustness of this interpretation is unclear, as 2-methylHopanoids occur in organisms besides cyanobacteria and their physiological functions are unknown. As a first step toward understanding the role of 2-MeBHP in cyanobacteria, we examined the expression and intercellular localization of Hopanoids in the three cell types of Nostoc punctiforme: vegetative cells, akinetes, and heterocysts. Cultures in which N. punctiforme had differentiated into akinetes contained approximately 10-fold higher concentrations of 2-methylHopanoids than did cultures that contained only vegetative cells. In contrast, 2-methylHopanoids were only present at very low concentrations in heterocysts. Hopanoid production initially increased threefold in cells starved of nitrogen but returned to levels consistent with vegetative cells within 2 weeks. Vegetative and akinete cell types were separated into cytoplasmic, thylakoid, and outer membrane fractions; the increase in Hopanoid expression observed in akinetes was due to a 34-fold enrichment of Hopanoid content in their outer membrane relative to vegetative cells. Akinetes formed in response either to low light or phosphorus limitation, exhibited the same 2-methylHopanoid localization and concentration, demonstrating that 2-methylHopanoids are associated with the akinete cell type per se. Because akinetes are resting cells that are not photosynthetically active, 2-methylHopanoids cannot be functionally linked to oxygenic photosynthesis in N. punctiforme.