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1.
Int J Mol Sci ; 23(4)2022 Feb 18.
Article in English | MEDLINE | ID: mdl-35216406

ABSTRACT

The possibility for an ecologically friendly and simple production of gold nanoparticles (AuNPs) with Chaga mushroom (Inonotus obliquus) (Ch-AuNPs) is presented in this study. Chaga extract's reducing potential was evaluated at varied concentrations and temperatures. The nanoparticles synthesized were all under 20 nm in size, as measured by TEM, which is a commendable result for a spontaneous synthesis method utilizing a biological source. The Ch-AuNPs showed anti-cancer chemotherapeutic effects on human brain cancer cells which is attributed to the biofunctionalization of the AuNPs with Chaga bioactive components during the synthesis process. Further, the photothermal ablation capability of the as-prepared gold nanoparticles on human brain cancer cells was investigated. It was found that the NIR-laser induced thermal ablation of cancer cells was effective in eliminating over 80% of the cells. This research projects the Ch-AuNPs as promising, dual modal (chemo-photothermal) therapeutic candidates for anti-cancer applications.


Subject(s)
Brain Neoplasms/drug therapy , Gold/chemistry , Gold/pharmacology , Inonotus/metabolism , Metal Nanoparticles/administration & dosage , Metal Nanoparticles/chemistry , Agaricales/drug effects , Cell Line , Cell Line, Tumor , Cell Survival/drug effects , Humans , Hyperthermia, Induced/methods
2.
Mater Sci Eng C Mater Biol Appl ; 128: 112323, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34474874

ABSTRACT

The standard scaffold-mediated delivery of drugs/biomolecules has been successful due to the unique attributes of scaffolds, specifically the electrospun polymeric scaffolds that mimic ECM are well suited for advanced regenerative applications. Cardiac tissue engineering includes the interpretation of cellular and molecular mechanisms concerning heart regeneration and identifying an efficient reprogramming strategy to overcome the limitation of delivery systems and enhance the reprogramming efficiency. This study is a step towards developing a functional scaffold through a parallel interpretation of electrospun PLLA scaffolds with two distinct topologies to achieve sustained delivery of two muscle-specific microRNAs (miR-1 and miR-133a) to directly reprogram the adult human cardiac fibroblasts into cardiomyocyte-like cells. Polyethyleneimine was used to form stable PEI-miRNA complexes through electrostatic interactions. These complexes were immobilized on the electrospun smooth and porous scaffolds, where a loading efficiency of ~96% for the fibronectin modified and ~38% for unmodified surfaces was observed, regardless of their surface topology. The in-vitro release experiment exhibited a biphasic release pattern of PEI-miRNA polyplexes from the scaffolds. These dual miRNA scaffold systems proved to be an excellent formulation since their combinatorial effect involving the topographic cues of electrospun fibers, and dual miRNAs helped control the cardiac fibroblast cell fate precisely.


Subject(s)
MicroRNAs , Fibroblasts , Humans , MicroRNAs/genetics , Myocytes, Cardiac , Polyethyleneimine , Tissue Engineering , Tissue Scaffolds
3.
PLoS One ; 16(3): e0248313, 2021.
Article in English | MEDLINE | ID: mdl-33705469

ABSTRACT

Magnetotactic bacteria (MTB) synthesize magnetosomes composed of membrane-enveloped magnetite (Fe3O4) and/or greigite (Fe3S4) nanoparticles in the cells. It is known that the magnetotactic Deltaproteobacteria are ubiquitous and inhabit worldwide in the sediments of freshwater and marine environments. Mostly known MTB belonging to the Deltaproteobacteria are dissimilatory sulfate-reducing bacteria that biomineralize bullet-shaped magnetite nanoparticles, but only a few axenic cultures have been obtained so far. Here, we report the isolation, cultivation and characterization of a dissimilatory sulfate-reducing magnetotactic bacterium, which we designate "strain FSS-1". We found that the strain FSS-1 is a strict anaerobe and uses casamino acids as electron donors and sulfate as an electron acceptor to reduce sulfate to hydrogen sulfide. The strain FSS-1 produced bullet-shaped magnetite nanoparticles in the cells and responded to external magnetic fields. On the basis of 16S rRNA gene sequence analysis, the strain FSS-1 is a member of the genus Desulfovibrio, showing a 96.7% sequence similarity to Desulfovibrio putealis strain B7-43T. Futhermore, the magnetosome gene cluster of strain FSS-1 was different from that of Desulfovibrio magneticus strain RS-1. Thus, the strain FSS-1 is considered to be a novel sulfate-reducing magnetotactic bacterium belonging to the genus Desulfovibrio.


Subject(s)
Desulfovibrio , Desulfovibrio/classification , Desulfovibrio/genetics , Desulfovibrio/isolation & purification , Desulfovibrio/metabolism , Ferrosoferric Oxide/metabolism , Magnetite Nanoparticles , RNA, Bacterial/genetics , RNA, Bacterial/metabolism , RNA, Ribosomal, 16S/genetics , RNA, Ribosomal, 16S/metabolism
4.
J Mater Chem B ; 7(39): 5896-5919, 2019 10 09.
Article in English | MEDLINE | ID: mdl-31423502

ABSTRACT

Malignant brain tumors remain a major cause of concern and mortality as successful treatment is hindered due to the poor transport and low penetration of chemotherapeutics across the blood-brain barrier (BBB). In this study, a nano formulation composed of chlorotoxin (CTX)-conjugated morusin loaded PLGA nanoparticles (PLGA-MOR-CTX) was devised against Glioblastoma Multiforme (GBM) and its anti-proliferative effects were evaluated in vitro. The synthesized nanoparticles were loaded with morusin, a naturally derived chemotherapeutic drug, and surface conjugated with CTX, a peptide derived from scorpion venom, highly specific for chloride channels (CIC-3) expressed in glioma tumor cells, as well as for matrix metalloproteinase (MMP-2), which is up regulated in the tumor microenvironment. Subsequently, the anti-cancer potential of the NPs was assessed in U87 and GI-1 (human glioblastoma) cells. Antiproliferative, cell apoptosis, and other cell-based assays demonstrated that the PLGA-MOR-CTX NPs resulted in enhanced inhibitory effects on U87 and GI-1 glioma cells. Prominent cytotoxicity parameters such as ROS generation, enhanced caspase activity, cytoskeletal destabilization, and inhibition of MMP-activity were observed in glioblastoma cells upon PLGA-MOR-CTX NP treatment. The cytocompatibility observed with normal human neuronal cells (HCN-1A) and the enhanced lethal effects in glioblastoma cells highlight the potential of PLGA-MOR-CTX nanoparticles as promising therapeutic nanocarriers towards GBM.


Subject(s)
Drug Carriers/chemistry , Flavonoids/chemistry , Glioblastoma/drug therapy , Molecular Targeted Therapy , Nanoparticles/chemistry , Polylactic Acid-Polyglycolic Acid Copolymer/chemistry , Scorpion Venoms/chemistry , Autophagy/drug effects , Biological Transport , Brain Neoplasms/drug therapy , Brain Neoplasms/pathology , Cell Line, Tumor , Cytoskeleton/drug effects , Cytoskeleton/metabolism , Drug Liberation , Glioblastoma/pathology , Humans , Matrix Metalloproteinase 2/metabolism , Matrix Metalloproteinase 9/metabolism , Reactive Oxygen Species/metabolism , Scorpion Venoms/pharmacology
5.
Heliyon ; 4(10): e00861, 2018 Oct.
Article in English | MEDLINE | ID: mdl-30364571

ABSTRACT

Rare sugars are defined as monosaccharides and their derivatives, which rarely exist in nature and have various beneficial effects on organisms, biomaterials and foods. Glycolipids are composed of sugars and lipids and have been intensively studied in various fields such as environmental engineering, nanotechnology and molecular biology. Here, we synthesise new types of glycolipids composed of rare sugars, glycerol and lipids (RSGLs), using 6 different types of rare sugars by combining the modified Fischer and lipase reverse reactions. We confirm the production of RSGLs by thin layer chromatography (TLC), Fourier-transform infrared (FT-IR) spectroscopy and matrix assisted laser desorption/ionisation time of flight mass spectroscopy (MALDI-TOF-MS) and investigate the cytotoxicity of RSGLs by lactate dehydrogenase (LDH) and alamar blue assays. We successfully synthesise novel RSGLs; i.e., D-ribose-glycorol-lipid, D-allose-glycorol-lipid, L-rhamnose-glycorol-lipid, L-lyxorse-glycorol-lipid, L-gulose-glycorol-lipid and L-fucose-glycorol-lipid. We finally clarify the effect of the concentration of those RSGLs on cytotoxicity, which is of great importance considering the utilisation of RSGLs particularly in the field of biomedicine.

6.
Anal Chem ; 89(22): 12450-12457, 2017 11 21.
Article in English | MEDLINE | ID: mdl-29063767

ABSTRACT

Combining the electrophoresis and conventional Coulter methods, we previously proposed the electrophoretic Coulter method (ECM), enabling simultaneous analysis of the size, number, and zeta potential of individual specimens. We validated the ECM experimentally using standard polystyrene particles and red blood cells (RBCs) from sheep; the latter was the first ECM application to biological particles in biotechnology research. However, specimens are prevented from passing through the ECM module aperture, which prevents accurate determination of the zeta potential of each specimen. This problem is caused by electro-osmotic flow (EOF) due to the high zeta potential at the ECM microchannel surfaces. To significantly improve ECM feasibility for biomedicine, we here propose a method to estimate the zeta potential at the ECM microchannel surfaces separate from the zeta potential of each specimen, by investigating the electric-field dependence of the specimen's experimental electrophoretic velocity. We minimize the zeta potential at the microchannel surfaces by applying an organic-molecule coating, and we suppress the surface zeta potential and its resultant EOF by optimizing the microchannel geometry. We demonstrate that the ECM can distinguish between different biological cells using the differences in zeta potential values and/or sizes. We also demonstrate that the ECM can determine the number of biomolecules attached to individual cells and identify whether the average cell state in an analyzed vial is alive or dead. The high-performance ECM can detect cellular morphology alterations, improve immunologic test sensitivity, and identify cell states (living, dying, and dead); this information is clinically useful for early diagnosis and its follow-up.


Subject(s)
Apoptosis , Cells, Cultured , Electrophoresis, Capillary/instrumentation , Humans , Particle Size , Surface Properties
7.
PLoS One ; 12(1): e0170932, 2017.
Article in English | MEDLINE | ID: mdl-28125741

ABSTRACT

Magnetotactic bacteria (MTB) synthesize magnetosomes composed of membrane-enveloped magnetite (Fe3O4) or greigite (Fe3S4) particles in the cells. Recently, several studies have shown some possibilities of controlling the biomineralization process and altering the magnetic properties of magnetosomes by adding some transition metals to the culture media under various environmental conditions. Here, we successfully grow Magnetospirillum magneticum strain RSS-1, which are isolated from a freshwater environment, and find that synthesis of magnetosomes are encouraged in RSS-1 in the presence of samarium and that each core magnetic crystal composed of magnetite is covered with a thin layer of samarium oxide (Sm2O3). The present results show some possibilities of magnetic recovery of transition metals and synthesis of some novel structures composed of magnetic particles and transition metals utilizing MTB.


Subject(s)
Ferrosoferric Oxide/analysis , Magnetosomes/chemistry , Magnetospirillum , Nanoparticles/chemistry , Oxides/analysis , Samarium/analysis
8.
Gan To Kagaku Ryoho ; 44(12): 1497-1499, 2017 Nov.
Article in Japanese | MEDLINE | ID: mdl-29394680

ABSTRACT

An 81-year-oldwoman with advancedgastric cancer was referredto our hospital. Preoperative contrast-enhancedCT revealeda roundcalcification of the splenic hilum with 15mm in diameter as a splenic artery aneurysm. She underwent transcatheter arterial embolization(TAE)for the splenic artery aneurysm. Celiac artery angiography showedcollateral arterial network of the spleen from left gastric artery. Surgery for the gastric cancer was performed1 4 days after TAE. We cut the right gastric andbilateral epigastric arteries. After the left gastric artery clamping, we performedintraoperative indocyanine green(ICG)fluorography. ICG fluorography confirmedthat the bloodflow of the upper thirdof the stomach andspleen were maintained. We safely performed distal gastrectomy, and the postoperative course was uneventful.


Subject(s)
Aneurysm/surgery , Spleen/blood supply , Stomach Neoplasms/diagnostic imaging , Aged, 80 and over , Disease Progression , Female , Fluorescent Dyes , Gastrectomy , Humans , Monitoring, Intraoperative , Spleen/surgery , Stomach Neoplasms/blood supply , Stomach Neoplasms/surgery
9.
Biochem Biophys Rep ; 8: 360-364, 2016 Dec.
Article in English | MEDLINE | ID: mdl-28955977

ABSTRACT

We present a simple method for efficient DNA ligation utilizing the heat generation of ferromagnetic particles subjected to an ac magnetic field. We carry out the ligation of DNA fragments with cohesive ends using T4 DNA ligase immobilized on the surface of ferromagnetic particles. When a radio frequency alternating magnetic field is applied, ferromagnetic particles dissipate heat and DNA ligase on the particles is selectively heated up and activated with little influence on the annealing of DNA ends, as a result of which the ligation efficiency increases. We show that the ligation efficiency increases with an increase in the field amplitude.

10.
PLoS One ; 10(5): e0127673, 2015.
Article in English | MEDLINE | ID: mdl-25993268

ABSTRACT

We propose a method of activating an enzyme utilizing heat generation from ferromagnetic particles under an ac magnetic field. We immobilize α-amylase on the surface of ferromagnetic particles and analyze its activity. We find that when α-amylase/ferromagnetic particle hybrids, that is, ferromagnetic particles, on which α-amylase molecules are immobilized, are subjected to an ac magnetic field, the particles generate heat and as a result, α-amylase on the particles is heated up and activated. We next prepare a solution, in which α-amylase/ferromagnetic particle hybrids and free, nonimmobilized chitinase are dispersed, and analyze their activities. We find that when the solution is subjected to an ac magnetic field, the activity of α-amylase immobilized on the particles increases, whereas that of free chitinase hardly changes; in other words, only α-amylase immobilized on the particles is selectively activated due to heat generation from the particles.


Subject(s)
Ferrous Compounds/chemistry , Hot Temperature , Magnetics , alpha-Amylases/metabolism , Enzyme Activation , Microscopy, Electron, Scanning
11.
PLoS One ; 10(5): e0127481, 2015.
Article in English | MEDLINE | ID: mdl-25993286

ABSTRACT

Magnetotactic bacteria (MTB) synthesize intracellular magnetic nanocrystals called magnetosomes, which are composed of either magnetite (Fe3O4) or greigite (Fe3S4) and covered with lipid membranes. The production of magnetosomes is achieved by the biomineralization process with strict control over the formation of magnetosome membrane vesicles, uptake and transport of iron ions, and synthesis of mature crystals. These magnetosomes have high potential for both biotechnological and nanotechnological applications, but it is still extremely difficult to grow MTB and produce a large amount of magnetosomes under the conventional cultural conditions. Here, we investigate as a first attempt the effect of polyethylene glycol (PEG) added to the culture medium on the increase in the yield of magnetosomes formed in Magnetospirillum magnetotacticum MS-1. We find that the yield of the formation of magnetosomes can be increased up to approximately 130 % by adding PEG200 to the culture medium. We also measure the magnetization of the magnetosomes and find that the magnetosomes possess soft ferromagnetic characteristics and the saturation mass magnetization is increased by 7 %.


Subject(s)
Magnetite Nanoparticles/chemistry , Magnetospirillum/metabolism , Polyethylene Glycols/pharmacology , Culture Media/pharmacology , Magnetite Nanoparticles/ultrastructure , Magnetosomes/drug effects , Magnetosomes/ultrastructure , Magnetospirillum/drug effects , Magnetospirillum/growth & development
12.
Int J Biol Macromol ; 76: 310-9, 2015 May.
Article in English | MEDLINE | ID: mdl-25749105

ABSTRACT

Polysaccharides that show finest bioactivities and physicochemical properties are always promising for bionanoscience applications. Mauran is such a macromolecule extracted from halophilic bacterium, Halomonas maura for biotechnology and nanoscience applications. Antioxidant properties of MR/CH nanoparticles were studied using biochemical assays to prove the versatility of these test nanoparticles for biomedical applications. Here, we demonstrate the prospects of extremophilic polysaccharide, mauran based nanoparticles for scavenging reactive oxygen species in both in vitro and ex vivo conditions. 5-fluorouracil loaded MR/CH nanoparticles were tested for anticancer proliferation and compared their therapeutic efficiency using breast adenocarcinoma and glioma cells. Fluorescently labeled nanoparticles were employed to show the cellular uptake of these nanocarriers using confocal microscopic imaging and flow cytometry.


Subject(s)
Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Antioxidants/chemistry , Antioxidants/pharmacology , Halomonas/chemistry , Nanoparticles/chemistry , Polysaccharides/chemistry , Polysaccharides/pharmacology , Cell Line, Tumor , Humans , Nanoparticles/administration & dosage , Nanoparticles/ultrastructure , Spectroscopy, Fourier Transform Infrared
13.
Gan To Kagaku Ryoho ; 42(12): 2300-2, 2015 Nov.
Article in Japanese | MEDLINE | ID: mdl-26805344

ABSTRACT

A 58-year-old woman presenting with abdominal distension was diagnosed with a tumor in the right ovary. A chest-abdominal-pelvic computed tomography scan revealed multiple lung metastases, multiple liver metastases, and peritoneal dissemination. Invasion of the rectum by peritoneal dissemination of the Douglas' pouch was suspected. She was diagnosed with Stage Ⅳ right ovarian cancer and was treated with preoperative chemotherapy. After chemotherapy, debulking surgery of the abdominal cavity (total hysterectomy, bilateral salpingo-oophorectomy, partial omentectomy, and Hartmann's procedure) was performed. Because there was swelling observed in multiple mesorectal lymph nodes, lymph node dissection was performed based on methods used for rectal cancer surgery. Postoperative histopathological examination revealed multiple mesorectal lymph node metastases arising from ovarian cancer. We suggest that mesorectal lymph node dissection be considered a part of debulking surgery for ovarian cancers that have invaded the rectum.


Subject(s)
Ovarian Neoplasms/pathology , Rectum/pathology , Female , Humans , Middle Aged , Neoplasm Invasiveness , Neoplasm Metastasis , Neoplasm Staging , Ovarian Neoplasms/drug therapy , Ovarian Neoplasms/surgery , Ovariectomy , Palliative Care
14.
PLoS One ; 8(6): e66528, 2013.
Article in English | MEDLINE | ID: mdl-23799111

ABSTRACT

We immobilize hydrolases such as lipase and chitinase on superparamagnetic particles, which are subjected to a rotational magnetic field, and measure the activities of the enzymes. We find that the activities of lipase and chitinase increase in the rotational magnetic field compared to those in the absence of a magnetic field and reach maximum at certain frequencies. The present methodology may well be utilized for the design and development of efficient micro reactors and micro total analysis systems (µ-TASs).


Subject(s)
Chitinases/chemistry , Enzymes, Immobilized/chemistry , Fungal Proteins/chemistry , Lipase/chemistry , Nanoparticles/chemistry , Candida albicans/enzymology , Magnetic Fields , Trichoderma/enzymology
15.
Biochem Biophys Res Commun ; 421(4): 763-7, 2012 May 18.
Article in English | MEDLINE | ID: mdl-22546557

ABSTRACT

Internalisation of nanoparticles conjugated with cell penetrating peptides is a promising approach to various drug delivery applications. Cell penetrating peptides such as transactivating transcriptional activator (TAT) peptides derived from HIV-1 proteins are effective intracellular delivery vectors for a wide range of nanoparticles and pharmaceutical agents thanks to their amicable ability to enter cells and minimum cytotoxicity. Although different mechanisms of intracellular uptake and localisation have been proposed for TAT conjugated nanoparticles, it is necessary to visualise the particles on a 3-D plane in order to investigate the actual intracellular uptake and localisation. Here, we study the intracellular localisation and trafficking of TAT peptide conjugated superparamagnetic ion oxide nanoparticles (TAT-SPIONs) using 3-D electron tomography. 3-D tomograms clearly show the location of TAT-SPIONs in a cell and their slow release from the endocytic vesicles into the cytoplasm. The present methodology may well be utilised for further investigations of the behaviours of nanoparticles in cells and eventually for the development of nano drug delivery systems.


Subject(s)
Ferric Compounds/metabolism , Magnetite Nanoparticles , Peptide Fragments/metabolism , tat Gene Products, Human Immunodeficiency Virus/metabolism , Biological Transport , Cell Line, Tumor , Cytoplasm/metabolism , Drug Delivery Systems , Electron Microscope Tomography , Ferric Compounds/chemistry , Humans , Peptide Fragments/chemistry , Transport Vesicles/metabolism , tat Gene Products, Human Immunodeficiency Virus/chemistry
16.
Biochem Biophys Res Commun ; 393(4): 779-82, 2010 Mar 19.
Article in English | MEDLINE | ID: mdl-20171160

ABSTRACT

We immobilize alpha-amylase extracted from Bacillus Iicheniformis on the surfaces of superparamagnetic particles and investigate the effect of a rotational magnetic field on the enzyme's activity. We find that the activity of the enzyme molecules immobilized on superparamagnetic particles increases in the rotational magnetic field and reaches maximum at a certain frequency. We clarify the effect of the cluster structures formed by the superparamagnetic particles on the activity. Enzyme reactions are enhanced even in a tiny volume of solution using the present method, which is very important for the development of efficient micro reactors and micro total analysis systems (mu-TAS).


Subject(s)
Enzymes, Immobilized/chemistry , Ferrosoferric Oxide/chemistry , Nanoparticles/chemistry , alpha-Amylases/chemistry , Electromagnetic Fields , Protein Conformation , Rotation
17.
Int J Syst Evol Microbiol ; 60(Pt 11): 2529-2534, 2010 Nov.
Article in English | MEDLINE | ID: mdl-19965994

ABSTRACT

Strain YSM-123(T) was isolated from commercial salt made from Japanese seawater in Niigata prefecture. Optimal NaCl and Mg(2+) concentrations for growth were 4.0-4.5 M and 5 mM, respectively. The isolate was a mesophilic and slightly alkaliphilic haloarchaeon, whose optimal growth temperature and pH were 37 °C and pH 8.0-9.0. Phylogenetic analysis based on 16S rRNA gene sequence analysis suggested that strain YSM-123(T) is a member of the phylogenetic group defined by the family Halobacteriaceae, but there were low similarities to type strains of other genera of this family (≤90 %); for example, Halococcus (similarity <89 %), Halostagnicola (<89 %), Natronolimnobius (<89 %), Halobiforma (<90 %), Haloterrigena (<90 %), Halovivax (<90 %), Natrialba (<90 %), Natronobacterium (<90 %) and Natronococcus (<90 %). The G+C content of the DNA was 63 mol%. Polar lipid analysis revealed the presence of phosphatidylglycerol, phosphatidylglycerophosphate methyl ester, disulfated diglycosyl diether and an unknown glycolipid. On the basis of the data presented, we propose that strain YSM-123(T) should be placed in a new genus and species, Natronoarchaeum mannanilyticum gen. nov., sp. nov. The type strain of Natronoarchaeum mannanilyticum is strain YSM-123(T) (=JCM 16328(T) =CECT 7565(T)).


Subject(s)
Halobacteriaceae/classification , Halobacteriaceae/isolation & purification , Sodium Chloride, Dietary/metabolism , Aerobiosis , Base Composition , DNA, Archaeal/genetics , Halobacteriaceae/genetics , Halobacteriaceae/metabolism , Molecular Sequence Data , Phylogeny , RNA, Ribosomal, 16S/genetics , Sodium Chloride, Dietary/analysis
18.
Int J Syst Evol Microbiol ; 60(Pt 4): 990-995, 2010 Apr.
Article in English | MEDLINE | ID: mdl-19666816

ABSTRACT

Two moderately halophilic and alkaliphilic bacteria, designated strains BH1(T) and HN5, were isolated from forest soil and garden soil, respectively, in Japan. Cells of strains BH1(T) and HN5 were non-motile, aerobic, bean-shaped, formed irregular clusters with 2-20 cells, Gram-positive and contained A1gamma, meso-diaminopimelic acid-type murein. Spore formation was not detected. Growth occurred in 5-25 % (w/v) NaCl (optimum, 10-15 %, w/v), at pH 6.0-10.0 (optimum, pH 8.5-9.0) and at 20-40 degrees C (optimum, 30 degrees C). The predominant isoprenoid quinones were menaquinone-7 and menaquinone-6. The phospholipids were diphosphatidylglycerol and phosphatidylglycerol. The major cellular fatty acids were i-C(15 : 0), i-C(17 : 0) and i-C(18 : 0). The DNA G+C content of strains BH1(T) and HN5 was 45 and 46 mol%, respectively. The 16S rRNA gene sequences of the two strains were 99.9 % similar. DNA-DNA hybridization results indicated high levels of relatedness (88 and 85 % reciprocally). Similarities with recognized species were less than 90.2 %. The phylogenetic and phenotypic characteristics indicated that strains BH1(T) and HN5 represent a novel species in a new genus, for which the name Geomicrobium halophilum gen. nov., sp. nov. is proposed. The type strain is BH1(T) (=JCM 15647(T)=DSM 21769(T)).


Subject(s)
Gram-Positive Bacteria/classification , Gram-Positive Bacteria/isolation & purification , Sodium Chloride , Soil Microbiology , Aerobiosis , Bacterial Typing Techniques , Base Composition , DNA, Ribosomal/analysis , DNA, Ribosomal/genetics , Fatty Acids/analysis , Genes, rRNA , Genotype , Gram-Positive Bacteria/genetics , Gram-Positive Bacteria/physiology , Hydrogen-Ion Concentration , Japan , Molecular Sequence Data , Nucleic Acid Hybridization , Phenotype , Phylogeny , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Species Specificity
19.
Biophys J ; 96(11): 4692-700, 2009 Jun 03.
Article in English | MEDLINE | ID: mdl-19486691

ABSTRACT

Nucleoside diphosphate kinases from haloarchaea Haloarcula quadrata (NDK-q) and H. sinaiiensis (NDK-s) are identical except for one out of 154 residues, i.e., Arg(31) in NDK-q and Cys(31) in NDK-s. However, the salt-dependent activity profiles of NDK-q and NDK-s are quite different: the optimal NaCl concentrations of NDK-q and NDK-s are 1 M and 2 M, respectively. We analyzed the relationships of the secondary, tertiary, and quaternary structures and NDK activity of these NDKs at various salt concentrations, and revealed that 1), NDK-q is present as a hexamer under a wide range of salt concentrations (0.2-4 M NaCl), whereas NDK-s is present as a hexamer at an NaCl concentration above 2 M and as a dimer at NaCl concentrations below 1 M; 2), dimeric NDK-s has lower activity than hexameric NDK-s; and 3), dimeric NDK-s has higher helicity than hexameric NDK-s. We also determined the crystal structure of hexameric NDK-q, and revealed that Arg(31) plays an important role in stabilizing the hexamer. Thus the substitution of Arg (as in NDK-q) to Cys (as in NDK-s) at position 31 destabilizes the hexameric assembly, and causes dissociation to less active dimers at low salt concentrations.


Subject(s)
Archaeal Proteins/chemistry , Nucleoside-Diphosphate Kinase/chemistry , Sodium Chloride/chemistry , Amino Acid Sequence , Archaeal Proteins/genetics , Circular Dichroism , Crystallization , Escherichia coli , Haloarcula , Models, Molecular , Molecular Sequence Data , Nucleoside-Diphosphate Kinase/genetics , Protein Stability , Protein Structure, Quaternary , Protein Structure, Secondary , Protein Structure, Tertiary , Structural Homology, Protein , X-Ray Diffraction
20.
Saline Syst ; 4: 16, 2008 Oct 29.
Article in English | MEDLINE | ID: mdl-18957135

ABSTRACT

Haloarchaeal strains require high concentrations of NaCl for their growth, with optimum concentrations of 10-30%. They display a wide variety of morphology and physiology including pH range for growth. Many strains grow at neutral to slightly alkaline pH, and some only at alkaline pH. However, no strain has been reported to grow only in acidic pH conditions within the family Halobacteriaceae.In this study, we isolated many halophiles capable of growth in a 20% NaCl medium adjusted to pH 4.5 from 28 commercially available salts. They showed growth at pH 4.0 to 6.5, depending slightly on the magnesium content. The most acidophilic strain MH1-52-1 isolated from an imported solar salt (pH of saturated solution was 9.0) was non-pigmented and extremely halophilic. It was only capable of growing at pH 4.2-4.8 with an optimum at pH 4.4 in a medium with 0.1% magnesium chloride, and at pH 4.0-6.0 (optimum at pH 4.0) in a medium with 5.0% magnesium. The 16S rRNA and DNA-dependent RNA polymerase subunit B' gene sequences demonstrated clearly that the strain MH1-52-1 represents a new genus in the family Halobacteriaceae.

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