Accelerated Iron Corrosion by Microbial Consortia Enriched from Slime-like Precipitates from a Corroded Metal Apparatus Deployed in a Deep-sea Hydrothermal System.

Microbiologically influenced corrosion refers to the corrosion of metal materials caused or promoted by microorganisms. Although some novel iron-corrosive microorganisms have been discovered in various manmade and natural freshwater and seawater environments, microbiologically influenced corrosion in the deep sea has not been investigated in detail. In the present study, we collected slime-like precipitates composed of corrosion products and microbial communities from a geochemical reactor set on an artificial hydrothermal vent for 14.

Species-specific Microorganisms in Acid-tolerant Chironomus Larvae Reared in a Neutral pH Range under Laboratory Conditions: Single Dataset Analysis.

To obtain a more detailed understanding of organismal acid tolerance, the larval microbiomes of 11 Chironomus species collected from acidic or neutral pH areas in Japan and reared at pH 7-8 under laboratory conditions were systematically compared using an amplicon sequencing ana-lysis. Evenness values were lower for the larval microbiomes of acid-tolerant Chironomus cf. riparius, Chironomus fusciceps, and Chironomus sulfurosus than for eight acid-sensitive species based on an alpha diversity ana-lysis.

Microbiologically influenced corrosion of stainless steel independent of sulfate-reducing bacteria.

The presence and activities of microorganisms on metal surfaces can affect corrosion. Microbial communities after such corrosion incidents have been frequently analyzed, but little is known about the dynamics of microbial communities in biofilms on different types of stainless steels, such as austenitic, martensitic, and duplex stainless steels. Here, we conducted immersion experiments on 10 types of stainless steels in a freshwater environment, where microbiologically influenced corrosion was observed.

Electrochemical Enrichment and Isolation of Electrogenic Bacteria from 0.22 µm Filtrate.

Ultramicrobacteria (UMB) that can pass through a 0.22 µm filter are attractive because of their novelty and diversity. However, isolating UMB has been difficult because of their symbiotic or parasitic lifestyles in the environment.

Novel Strain Induces Severe Corrosion by Retrieving Electrons from Fe under a Freshwater Environment.

Methanogens capable of accepting electrons from Fe cause severe corrosion in anoxic conditions. In previous studies, all iron-corrosive methanogenic isolates were obtained from marine environments. However, the presence of methanogens with corrosion ability using Fe as an electron donor and their contribution to corrosion in freshwater systems is unknown.

Thermal stability tuning without affecting gas-binding function of Thermochromatium tepidum cytochrome c'.

Hydrogenophilus thermoluteolus, Thermochromatium tepidum, and Allochromatium vinosum, which grow optimally at 52, 49, and 25 °C, respectively, have homologous cytochromes c' (PHCP, TTCP, and AVCP, respectively) exhibiting at least 50% amino acid sequence identity. Here, the thermal stability of the recombinant TTCP protein was first confirmed to be between those of PHCP and AVCP. Structure comparison of the 3 proteins and a mutagenesis study on TTCP revealed that hydrogen bonds and hydrophobic interactions between the heme and amino acid residues were responsible for their stability differences.

Accelerated glucose metabolism in hyphae-dispersed Aspergillus oryzae is suitable for biological production.

Recently, a hyphae-dispersed type of filamentous fungus Aspergillus oryzae was constructed via genetic engineering, and industrial applications are expected due to the ease of handling and to the level of protein production properties. In this study, we constructed cellulase-expressing strains using wild-type and hyphae-dispersed strains to investigate the correlation between protein productivity and metabolism. Compared with the original strain, the hyphae-dispersed cellulase-expressing strain showed elevated cellulase activity, rapid glucose consumption, increased mycelial dry weight, an increased expression of cellulase genes, and activated respiration activity.

Thermal destabilization mechanism of cytochrome c' from psychrophilic Shewanella violacea.

Cytochrome c' is a nitric oxide (NO)-binding heme protein found in Gram negative bacteria. The thermal stability of psychrophilic Shewanella violacea cytochrome c' (SVCP) is lower than those of its homologues from other 2 psychrophilic Shewanella species, indicating that thermal destabilization mechanism for low-temperature adaptation accumulates in SVCP. In order to understand this mechanism at the amino acid level, here the stability and function of SVCP variants, modeled using the 2 homologues, were examined.

Pyruvate metabolism redirection for biological production of commodity chemicals in aerobic fungus Aspergillus oryzae.

Pyruvate is a central metabolite for the biological production of various chemicals. In eukaryotes, pyruvate produced by glycolysis is used in conversion to ethanol and lactate and in anabolic metabolism in the cytosol, or is transported into the mitochondria for use as a substrate in the tricarboxylic acid (TCA) cycle. In this study, we focused on controlling pyruvate metabolism in aerobic microorganisms for the biological production of various chemicals.

Differences in biochemical properties of two 5'-nucleotidases from deep- and shallow-sea Shewanella species under various harsh conditions.

Deep-sea Shewanella violacea 5'-nucleotidase (SVNTase) activity exhibited higher NaCl tolerance than that of a shallow-sea Shewanella amazonensis homologue (SANTase), the sequence identity between them being 70.4%. Here, SVNTase exhibited higher activity than SANTase with various inorganic salts, similar to the difference in their NaCl tolerance.

Stability of cytochromes c' from psychrophilic and piezophilic Shewanella species: implications for complex multiple adaptation to low temperature and high hydrostatic pressure.

The stability of dimeric cytochrome c' from a thermophile, as compared with that of a homologous mesophilic counterpart, is attributed to strengthened interactions around the heme and at the subunit-subunit interface, both of which are molecular interior regions. Here, we showed that interactions in the equivalent interior regions of homologous cytochromes c' from two psychrophiles, Shewanella benthica and Shewanella violacea (SBCP and SVCP, respectively) were similarly weakened as compared with those of the counterparts of psychrophilic Shewanella livingstonensis and mesophilic Shewanella amazonensis (SLCP and SACP, respectively), and consistently the stability of SVCP, SLCP, and SACP increased in that order. Therefore, the stability of cytochromes c' from the psychrophile, mesophile, and thermophile is systematically regulated in their molecular interior regions.

Modified expression of multi-cellulases in a filamentous fungus Aspergillus oryzae.

Aspergillus oryzae, a filamentous fungus, can secrete large amounts of enzymes extracellularly. We constructed a genetically engineered A. oryzae that simultaneously produced cellobiohydrolase, endoglucanase, and β-glucosidase by integrating multiple copies of the genes encoding these cellulases into fungal chromosomes.

Automated image analysis tool for tumor volume growth rate to guide precision cancer therapy: EGFR-mutant non-small-cell lung cancer as a paradigm.

Purpose: To develop an automated analytic module for calculation of tumor growth rate from serial CT scans and to apply the module and evaluate reproducibility in a pilot cohort of advanced NSCLC patients with EGFR mutations treated with EGFR tyrosine kinase inhibitors.

Materials And Methods: The module utilized a commercially available image-processing workstation equipped with a validated tumor volume measurement tool. An automated analytic software module was programmed with the capability to record and display serial tumor volume changes and to calculate tumor volume growth rate over time and added to the workstation.

Biochemical and thermodynamic analyses of energy conversion in extremophiles.

A variety of extreme environments, characterized by extreme values of various physicochemical parameters (temperature, pressure, salinity, pH, and so on), are found on Earth. Organisms that favorably live in such extreme environments are called extremophiles. All living organisms, including extremophiles, must acquire energy to maintain cellular homeostasis, including extremophiles.

An extracellular [NiFe] hydrogenase mediating iron corrosion is encoded in a genetically unstable genomic island in Methanococcus maripaludis.

Certain methanogens deteriorate steel surfaces through a process called microbiologically influenced corrosion (MIC). However, the mechanisms of MIC, whereby methanogens oxidize zerovalent iron (Fe), are largely unknown. In this study, Fe-corroding Methanococcus maripaludis strain OS7 and its derivative (strain OS7mut1) defective in Fe-corroding activity were isolated.

Commonly stabilized cytochromes c from deep-sea Shewanella and Pseudomonas.

Two cytochromes c (SBcytc and SVcytc) have been derived from Shewanella living in the deep-sea, which is a high pressure environment, so it could be that these proteins are more stable at high pressure than at atmospheric pressure, 0.1 MPa. This study, however, revealed that SBcytc and SVcytc were more stable at 0.

Direct and highly productive conversion of cyanobacteria to ethanol with CaCl addition.

Background: The cyanobacterium shows promise as a carbohydrate feedstock for biofuel production. The glycogen accumulated in can be extracted by lysozyme-degrading the peptidoglycan layer of the bacterial cell walls. The extracted glycogen can be converted to ethanol through hydrolysis by amylolytic enzymes and fermentation by the yeast .

Stabilization of mesophilic Allochromatium vinosum cytochrome c' through specific mutations modeled by a thermophilic homologue.

AVCP cytochrome c' from mesophilic Allochromatium vinosum exhibits lower stability than a thermophilic counterpart, Hydrogenophilus thermoluteolus cytochrome c' (PHCP), in which the six specific amino acid residues that are not conserved in AVCP are responsible for its stability. Here we measured the stability of AVCP variants carrying these specific residues instead of the original AVCP ones. Among the six single AVCP variants, all of which formed a dimeric structure similar to that of the wild-type, three were successfully stabilized compared with the wild-type, while one showed lower stability than the wild-type.

Future insights in fungal metabolic engineering.

Filamentous fungi exhibit versatile abilities, including organic acid fermentation, protein production, and secondary metabolism, amongst others, and thus have applications in the medical and food industries. Previous genomic analyses of several filamentous fungi revealed their further potential as host microorganisms for bioproduction. Recent advancements in molecular genetics, marker recycling, and genome editing could be used to alter transformation and metabolism, based on optimized design carbolated with computer science.

Pseudomonas aeruginosa cytochrome c denaturation by five systematic urea derivatives that differ in the alkyl chain length.

Reversible denaturation of Pseudomonas aeruginosa cytochrome c (PAc) could be followed using five systematic urea derivatives that differ in the alkyl chain length, i.e. urea, N-methylurea (MU), N-ethylurea (EU), N-propylurea (PU), and N-butylurea (BU).

Pyrophosphate hydrolysis in the extremely halophilic archaeon Haloarcula japonica is catalyzed by a single enzyme with a broad ionic strength range.

The soluble protein fraction of the extremely halophilic archaeon Haloarcula japonica exhibits substantial inorganic pyrophosphate (PPi) hydrolysis activity in the presence of 2-4 M NaCl (Wakai et al, J Biol Chem 288:29247-29251, 2013), which provides high ionic strength (2-4). In this study, much higher PPi hydrolysis activity was unexpectedly detected, even with 0 M NaCl in the presence of 100-200 mM MgSO, providing a much lower ionic strength of 0.4-0.

Structural and functional insights into thermally stable cytochrome c' from a thermophile.

Unlabelled: Thermophilic Hydrogenophilus thermoluteolus cytochrome c' (PHCP) exhibits higher thermal stability than a mesophilic counterpart, Allochromatium vinosum cytochrome c' (AVCP), which has a homo-dimeric structure and ligand-binding ability. To understand the thermal stability mechanism and ligand-binding ability of the thermally stable PHCP protein, the crystal structure of PHCP was first determined. It formed a homo-dimeric structure, the main chain root mean square deviation (rmsd) value between PHCP and AVCP being 0.

Difference in NaCl tolerance of membrane-bound 5'-nucleotidases purified from deep-sea and brackish water Shewanella species.

Shewanella species are widely distributed in sea, brackish, and fresh water areas, growing psychrophilically or mesophilically, and piezophilically or piezo-sensitively. Here, membrane-bound 5'-nucleotidases (NTases) from deep-sea Shewanella violacea and brackish water Shewanella amazonensis were examined from the aspect of NaCl tolerance to gain an insight into protein stability against salt. Both NTases were single polypeptides with molecular masses of ~59 kDa, as determined on mass spectroscopy.

Comparative study on stabilization mechanism of monomeric cytochrome c from deep-sea piezophilic Shewanella violacea.

Monomeric cytochrome c from deep-sea piezophilic Shewanella violacea (SVcytc) was stable against heat and denaturant compared with the homologous protein from shallow-sea piezo-sensitive Shewanella livingstonensis (SLcytc). Here, the SVcytc crystal structure revealed that the Lys-50 side chain on the flexible loop formed a hydrogen bond with heme whereas that of corresponding hydrophobic Leu-50 could not form such a bond in SLcytc, which appeared to be one of possible factors responsible for the difference in stability between the two proteins. This structural insight was confirmed by a reciprocal mutagenesis study on the thermal stability of these two proteins.

From mannan to bioethanol: cell surface co-display of β-mannanase and β-mannosidase on yeast Saccharomyces cerevisiae.

Background: Mannans represent the largest hemicellulosic fraction in softwoods and also serve as carbohydrate stores in various plants. However, the utilization of mannans as sustainable resources has been less advanced in sustainable biofuel development. Based on a yeast cell surface-display technology that enables the immobilization of multiple enzymes on the yeast cell walls, we constructed a recombinant Saccharomyces cerevisiae strain that co-displays β-mannanase and β-mannosidase; this strain is expected to facilitate ethanol fermentation using mannan as a biomass source.