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Marfil-Santana Miguel David,O’Connor-Sánchez Aileen,Ramírez-Prado Jorge Humberto,De los Santos-Briones Cesar,López-Aguiar,Lluvia Korynthia,Rojas-Herrera Rafael,Lago-Lestón Asunción,Prieto-Davó Alejand 한국미생물학회 2016 The journal of microbiology Vol.54 No.11
The need for new antibiotics has sparked a search for the microbes that might potentially produce them. Current sequencing technologies allow us to explore the biotechnological potential of microbial communities in diverse environments without the need for cultivation, benefitting natural product discovery in diverse ways. A relatively recent method to search for the possible production of novel compounds includes studying the diverse genes belonging to polyketide synthase pathways (PKS), as these complex enzymes are an important source of novel therapeutics. In order to explore the biotechnological potential of the microbial community from the largest underground aquifer in the world located in the Yucatan, we used a polyphasic approach in which a simple, non-computationally intensive method was coupled with direct amplification of environmental DNA to assess the diversity and novelty of PKS type I ketosynthase (KS) domains. Our results suggest that the bioinformatic method proposed can indeed be used to assess the novelty of KS enzymes; nevertheless, this in silico study did not identify some of the KS diversity due to primer bias and stringency criteria outlined by the metagenomics pipeline. Therefore, additionally implementing a method involving the direct cloning of KS domains enhanced our results. Compared to other freshwater environments, the aquifer was characterized by considerably less diversity in relation to known ketosynthase domains; however, the metagenome included a family of KS type I domains phylogenetically related, but not identical, to those found in the curamycin pathway, as well as an outstanding number of thiolases. Over all, this first look into the microbial community found in this large Yucatan aquifer and other fresh water free living microbial communities highlights the potential of these previously overlooked environments as a source of novel natural products.
강인규,Dav 한국식품저장유통학회 1997 한국식품저장유통학회지 Vol.4 No.1
In our studies on the role of $\beta$-galactosidase in fruit softening, significant difficulty, was encountered in our attempts to extract RNA from persimmon(Diospyros kaki L. cv. Fuyu) fruit due to astringency and tannin content. Initial, unsuccessful RNA extractions involved methods using guanidinium isothiocyanate/CsCl with and without polyvinylpyrrolidone(PVP), phenol/sodium lauryl sulfate(SDS), guanidinium hydrochloride, as well as polysomal RNA purification method that used 0.2 M Tris-HCI (pH 9.0) containing KCI, Mg-acetate, EDTA, $\beta$-mercaptoethanol, and sucrose. A method was devised which employed treatment of fruit with CO2 gas to diminish astringency prior to RNA extraction, followed by extraction of tissue powders with Proteinase K extraction buffer containing PVP and ascorbate at an alkaline pH. This procedure resulted in the removal of tannins and other polyphenolics and extraction of relatively large amount of high-quality RNA suitable for cDNA library construction and polymerase chain reaction(PCR). Futhermore, the procedure does not use the toxic and corrosive chemical guanidinium isothiocyanate or require ultracentrifugation.
The Icebreaker Life Mission to Mars: A Search for Biomolecular Evidence for Life
McKay, Christopher P.,Stoker, Carol R.,Glass, Brian J.,Davé,, Arwen I.,Davila, Alfonso F.,Heldmann, Jennifer L.,Marinova, Margarita M.,Fairen, Alberto G.,Quinn, Richard C.,Zacny, Kris A.,Paulsen Mary Ann Liebert 2013 Astrobiology Vol.13 No.4
<P>The search for evidence of life on Mars is the primary motivation for the exploration of that planet. The results from previous missions, and the Phoenix mission in particular, indicate that the ice-cemented ground in the north polar plains is likely to be the most recently habitable place that is currently known on Mars. The near-surface ice likely provided adequate water activity during periods of high obliquity, ? 5 Myr ago. Carbon dioxide and nitrogen are present in the atmosphere, and nitrates may be present in the soil. Perchlorate in the soil together with iron in basaltic rock provides a possible energy source for life. Furthermore, the presence of organics must once again be considered, as the results of the Viking GCMS are now suspect given the discovery of the thermally reactive perchlorate. Ground ice may provide a way to preserve organic molecules for extended periods of time, especially organic biomarkers. The Mars Icebreaker Life mission focuses on the following science goals: (1) Search for specific biomolecules that would be conclusive evidence of life. (2) Perform a general search for organic molecules in the ground ice. (3) Determine the processes of ground ice formation and the role of liquid water. (4) Understand the mechanical properties of the martian polar ice-cemented soil. (5) Assess the recent habitability of the environment with respect to required elements to support life, energy sources, and possible toxic elements. (6) Compare the elemental composition of the northern plains with midlatitude sites. The Icebreaker Life payload has been designed around the Phoenix spacecraft and is targeted to a site near the Phoenix landing site. However, the Icebreaker payload could be supported on other Mars landing systems. Preliminary studies of the SpaceX Dragon lander show that it could support the Icebreaker payload for a landing either at the Phoenix site or at midlatitudes. Duplicate samples could be cached as a target for possible return by a Mars Sample Return mission. If the samples were shown to contain organic biomarkers, interest in returning them to Earth would be high.</P>
Wong, Vanessa K,Baker, Stephen,Pickard, Derek J,Parkhill, Julian,Page, Andrew J,Feasey, Nicholas A,Kingsley, Robert A,Thomson, Nicholas R,Keane, Jacqueline A,Weill, Franç,ois-Xavier,Edwards, Dav Nature Pub. Co 2015 Nature genetics Vol.47 No.6
The emergence of multidrug-resistant (MDR) typhoid is a major global health threat affecting many countries where the disease is endemic. Here whole-genome sequence analysis of 1,832 Salmonella enterica serovar Typhi (S. Typhi) identifies a single dominant MDR lineage, H58, that has emerged and spread throughout Asia and Africa over the last 30 years. Our analysis identifies numerous transmissions of H58, including multiple transfers from Asia to Africa and an ongoing, unrecognized MDR epidemic within Africa itself. Notably, our analysis indicates that H58 lineages are displacing antibiotic-sensitive isolates, transforming the global population structure of this pathogen. H58 isolates can harbor a complex MDR element residing either on transmissible IncHI1 plasmids or within multiple chromosomal integration sites. We also identify new mutations that define the H58 lineage. This phylogeographical analysis provides a framework to facilitate global management of MDR typhoid and is applicable to similar MDR lineages emerging in other bacterial species.
Berenise Borges-Contreras,Cecilia Eugenia Martı´nez-Sa´nchez,Erasmo Herman-Lara,Jesu´s Rodrı´guez-Miranda,Betsabe´ Herna´ndez-Santos,Jose´ Manuel Jua´rez-Barrientos,Carlos Martı´n Guerra-Almonacid,Dav 한국식품영양과학회 2019 Journal of medicinal food Vol.22 No.3
Mojarra of Nile tilapia (Oreochromis niloticus) skeleton was used as protein source for the preparation of protein hydrolysates and peptide fractions with angiotensin-converting enzyme (ACE) inhibitory activity. The flour presented a content of 34.92% protein and a brightness (luminosity, L*) of 82.29. Protein hydrolysates were obtained from the protein-rich flour with the enzymes Flavourzyme® and Alcalase® reaching degree of hydrolysis (%DH) of 52% and 67% at 100 min of reaction, respectively. Both hydrolysates showed low-molecular-weight (MW) peptides estimated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis. The hydrolysates obtained with Flavourzyme at 60 min and at 80 min with Alcalase showed greater ACE inhibitory activity with IC50 values of 0.238 and 0.344 mg/mL, respectively. The peptide fraction A (MW >10 kDa) with Flavourzyme and fraction B (MW = 10–5 kDa) with Alcalase obtained by ultrafiltration of hydrolysates with higher DH presented IC50 of 0.728 and 0.354 mg/mL, respectively, whereas peptide fraction C (MW = 5–3 kDa) with both enzymes hydrolysates with greater ACE inhibitory activity showed IC50 values of 0.470 and 0.634 mg/mL. The components obtained in this study could be used as functional ingredients in the design and development of functional foods.
Lee, Joon-Hee,Choi, Sun-Hye,Kwon, Oh-Seung,Shin, Tae-Joon,Lee, Jun-Ho,Lee, Byung-Hwan,Yoon, In-Soo,Pyo, Mi Kyung,Rhim, Hyewhon,Lim, Yoong-Ho,Shim, Yhong-Hee,Ahn, Ji-yun,Kim, Hyoung-Choon,Chitwood, Dav Pharmaceutical Society of Japan 2007 BIOLOGICAL & PHARMACEUTICAL BULLETIN Vol.30 No.11
<P>The backbone structure of ginsenosides, active ingredients of <I>Panax ginseng</I>, is similar with that of sterol, especially cholesterol. <I>Caenorhabditis elegans</I> (<I>C. elegans</I>) is one of free living nematodes and is well-established animal model for biochemical and genetic studies. <I>C. elegans</I> cannot synthesize <I>de novo</I> cholesterol, although cholesterol is essential requirement for its growth and development. In the present study, we investigated the effects of ginseng total saponins (GTS) on the average brood size, growth, development, worm size, and life span of <I>C. elegans</I> in cholesterol-deprived and -fed medium. Cholesterol deprivation caused damages on normal growth, reproduction, and life span of worms throughout F1 to F3 generations. GTS supplement to cholesterol-deprived medium restored the growth, reproduction, and life span of worms as much as cholesterol alone-fed medium. GTS co-supplement to cholesterol-fed medium not only promoted worm reproduction but also induced bigger worms and faster growth than cholesterol-fed medium. In study to identify which ginsenosides are responsible for life span restoring effects of GTS, we found that ginsenoside Rc supplement not only restored life span of worms grown in cholesterol-deprived medium but also prolonged life span of worms grown in cholesterol-fed medium. Worms grown in medium supplemented with ginsenoside Rb<SUB>1</SUB> or Rc to cholesterol-deprived medium exhibited strong filipin staining, in which filipin forms tight and specific complexes with 3β-hydroxy sterols. These results show a possibility that ginsenosides could be utilized by <I>C. elegans</I> as a sterol substitute and further indicate that ginsenoside Rc is the component of <I>Panax ginseng</I> that prolongs the life span of <I>C. elegans</I>.</P>