The Thermal-Stable LH1-RC Complex of a Hot Spring Purple Bacterium Powers Photosynthesis with Extremely Low-Energy Near-Infrared Light.

is a hot spring purple nonsulfur phototrophic bacterium that contains bacteriochlorophyll (BChl) . Here, we present a 2.21 Å cryo-EM structure of the thermostable light-harvesting 1-reaction center (LH1-RC) complex from .

High-resolution structure and biochemical properties of the LH1-RC photocomplex from the model purple sulfur bacterium, Allochromatium vinosum.

The mesophilic purple sulfur phototrophic bacterium Allochromatium (Alc.) vinosum (bacterial family Chromatiaceae) has been a favored model for studies of bacterial photosynthesis and sulfur metabolism, and its core light-harvesting (LH1) complex has been a focus of numerous studies of photosynthetic light reactions. However, despite intense efforts, no high-resolution structure and thorough biochemical analysis of the Alc.

Heterologous expression and characterization of salt-tolerant β-glucosidase from xerophilic Aspergillus chevalieri for hydrolysis of marine biomass.

A salt-tolerant exo-β-1,3-glucosidase (BGL_MK86) was cloned from the xerophilic mold Aspergillus chevalieri MK86 and heterologously expressed in A. oryzae. Phylogenetic analysis suggests that BGL_MK86 belongs to glycoside hydrolase family 5 (aryl-phospho-β-D-glucosidase, BglC), and exhibits D-glucose tolerance.

Improvement in salt-tolerance of Aspergillus oryzae γ-glutamyl transpeptidase via protein chimerization with Aspergillus sydowii homolog.

γ-Glutamyl transpeptidase is one of the key enzymes involved in glutamate production during high-salt fermentation of soy sauce and miso by koji mold, Aspergillus oryzae. However, the activity of γ-glutamyl transpeptidase from A. oryzae (AOggtA) is markedly reduced in the presence of NaCl, thus classifying it as a non-salt-tolerant enzyme.

Isolation and characterization of a salt-tolerant γ-glutamyl transpeptidase from xerophilic .

Unlabelled: Xerophilic molds isolated from halo-alkaliphilic and dry environments are attractive genetic resources for obtaining salt- and osmo-adaptive enzymes. MA0196 secreted the largest amount of γ-glutamyl transpeptidase (GGT) during solid-state fermentation at a low initial water activity (  = 0.85).

Salt- and pH-Dependent Thermal Stability of Photocomplexes from Extremophilic Bacteriochlorophyll -Containing Species.

() species are the most halophilic and alkaliphilic of all purple bacteria. exhibits the lowest LH1 transition energy among phototrophic organisms and is the only known triply extremophilic anoxygenic phototroph, displaying a thermophilic, halophilic, and alkaliphilic phenotype. Recently, we reported that electrostatic charges are responsible for the unusual spectroscopic properties of the LH1 complex.

Improvement of the halotolerance of a Bacillus serine protease by protein surface engineering.

A moderately halotolerant serine protease was previously isolated from Bacillus subtilis from salted, fermented food. Eight mutation sites on the protein surface were selected for protein engineering based on sequence and structural comparisons with moderately halotolerant proteases and homologous non-halotolerant proteases. The newly constructed multiple mutants with substituted Asp and Arg residues were compared with the recombinant wild type (rApr) and the previously constructed mAla-8 substituted with Ala to analyze the contribution of protein surface charge to the salt adaptation of the protease.

Electrostatic charge controls the lowest LH1 Q transition energy in the triply extremophilic purple phototrophic bacterium, Halorhodospira halochloris.

Halorhodospira (Hlr.) halochloris is a unique phototrophic purple bacterium because it is a triple extremophile-the organism is thermophilic, alkalophilic, and halophilic. The most striking photosynthetic feature of Hlr.

Identification and characterization of extracellular enzymes secreted by Aspergillus spp. involved in lipolysis and lipid-antioxidation during katsuobushi fermentation and ripening.

A mild-flavored soup stock made from katsuobushi is an important element of traditional Japanese cuisine and is the basic seasoning responsible for the taste. Fermented and ripened katsuobushi, known as karebushi, is manufactured by simmering skipjack tuna that is then smoke-dried, fermented, and ripened in a repeated molding process by five dominant Aspergillus species. Here, our aim was to characterize and identify the lipolytic enzymes secreted by the dominant Aspergillus species, especially A.

Quinone transport in the closed light-harvesting 1 reaction center complex from the thermophilic purple bacterium Thermochromatium tepidum.

Redox-active quinones play essential roles in efficient light energy conversion in type-II reaction centers of purple phototrophic bacteria. In the light-harvesting 1 reaction center (LH1-RC) complex of purple bacteria, Q is converted to QH upon light-induced reduction and QH is transported to the quinone pool in the membrane through the LH1 ring. In the purple bacterium Rhodobacter sphaeroides, the C-shaped LH1 ring contains a gap for quinone transport.

Lycopene-Family Carotenoids Confer Thermostability on Photocomplexes from a New Thermophilic Purple Bacterium.

is a newly described thermophilic purple bacterium containing bacteriochlorophyll . Using purified light-harvesting 1 reaction center (LH1-RC) core complexes from . , we compared the biochemical, spectroscopic, and thermal denaturation properties of these complexes with those of its mesophilic counterpart, .

Characterization of surface Aspergillus community involved in traditional fermentation and ripening of katsuobushi.

A soup stock made from katsuobushi is an important element of, and the basic seasoning responsible for the taste of, traditional Japanese cuisine. Fermented and ripened katsuobushi, called karebushi, is manufactured via a repeated molding process on the katsuobushi surface. Our aim was to characterize the surface Aspergillus community and their enzymes involved in the fermentation and ripening.

A Dual Role for Ca in Expanding the Spectral Diversity and Stability of Light-Harvesting 1 Reaction Center Photocomplexes of Purple Phototrophic Bacteria.

The light-harvesting 1 reaction center (LH1-RC) complex in the purple sulfur bacterium Thiorhodovibrio ( Trv.) strain 970 cells exhibits its LH1 Q transition at 973 nm, the lowest-energy Q absorption among purple bacteria containing bacteriochlorophyll a (BChl a). Here we characterize the origin of this extremely red-shifted Q transition.

Bradyrhizobium diazoefficiens USDA110 PhaR functions for pleiotropic regulation of cellular processes besides PHB accumulation.

Background: Bradyrhizobium diazoefficiens USDA110 nodulates soybeans for nitrogen fixation. It accumulates poly-3-hydroxybutyrate (PHB), which is of physiological importance as a carbon/energy source for survival during starvation, infection, and nitrogen fixation conditions. PHB accumulation is orchestrated by not only the enzymes for PHB synthesis but also PHB-binding phasin proteins (PhaPs) stabilizing the PHB granules.

Isolation and characterization of an aspartic protease able to hydrolyze and decolorize heme proteins from Aspergillus glaucus.

Background: The xerophilic Aspergillus molds, Aspergillus glaucus and Aspergillus repens, have been used in the ripening and fermentation of dried tuna bonito (katsuobushi). These molds, and especially their extracellular hydrolytic enzymes, may also be of wider industrial value.

Results: Aspergillus glaucus strain MA0196 produces different types of hydrolytic enzymes, including amylase, serine protease, aspartic protease, lipase and cellulase, depending on the composition of the medium.

Metabolism of steroids by cytochrome P450 2C9 variants.

CYP2C9 is a human microsomal cytochrome P450c (CYP). Much variation in CYP2C9 levels and activity can be attributed to polymorphisms of this gene. Wild-type CYP2C9 and ten mutants were co-expressed with NADPH-cytochrome P450 reductase in Escherichia coli.

Biochemical and Spectroscopic Characterizations of a Hybrid Light-Harvesting Reaction Center Core Complex.

The light-harvesting 1 reaction center (LH1-RC) complex from Thermochromatium tepidum exhibits a largely red-shifted LH1 Q absorption at 915 nm due to binding of Ca, resulting in an "uphill" energy transfer from LH1 to the reaction center (RC). In a recent study, we developed a heterologous expression system (strain TS2) to construct a functional hybrid LH1-RC with LH1 from Tch. tepidum and the RC from Rhodobacter sphaeroides [Nagashima, K.

Direct bioconversion of rice residue from canteen waste into lipids by new amylolytic oleaginous yeast Sporidiobolus pararoseus KX709872.

The new amylolytic oleaginous red yeast, Sporidiobolus pararoseus KX709872, produced both α-amylase (540 ± 0.09 mU/mL) and amyloglucosidase (23 ± 0.00 mU/mL) and showed good ability to directly convert rice residue from canteen waste to biomass and lipids.

An integrated process for xylooligosaccharide and bioethanol production from corncob.

An integrated process for xylooligosaccharides (XOs) and bioethanol production from corncob was investigated. XOs were produced by a consecutive process of KOH treatment and hydrolysis by an in-house thermostable endo-xylanase from Streptomyces thermovulgaris. XO yields of 0.

Rapid conjugative mobilization of a 100 kb segment of Bacillus subtilis chromosomal DNA is mediated by a helper plasmid with no ability for self-transfer.

Background: The conjugative plasmid, pLS20, isolated from Bacillus subtilis natto, has an outstanding capacity for rapid self-transfer. In addition, it can function as a helper plasmid, mediating the mobilization of an independently replicating co-resident plasmid.

Results: In this study, the oriT sequence of pLS20cat (oriT) was eliminated to obtain the plasmid, pLS20catΔoriT.

Characterization and mutation analysis of a halotolerant serine protease from a new isolate of Bacillus subtilis.

Objectives: A bacterial halotolerant enzyme was characterized to understand the molecular mechanism of salt adaptation and to explore its protein engineering potential.

Results: Halotolerant serine protease (Apr_No16) from a newly isolated Bacillus subtilis strain no. 16 was characterized.

Metabolism of 7-ethoxycoumarin, flavanone and steroids by cytochrome P450 2C9 variants.

CYP2C9 is a human microsomal cytochrome P450c (CYP). Much of the variation in CYP2C9 levels and activity can be attributed to polymorphisms of this gene. Wild-type CYP2C9 and mutants were coexpressed with NADPH-cytochrome P450 reductase in Escherichia coli.

Homology modeling and prediction of the amino acid residues participating in the transfer of acetyl-CoA to arylalkylamine by the N-acetyltransferase from Chryseobacterium sp.

Objectives: To predict the amino acid residues playing important roles in acetyl-CoA and substrate binding and to study the acetyl group transfer mechanism of Chryseobacterium sp. 5-3B N-acetyltransferase (5-3B NatA).

Results: A 3-dimensional homology model of 5-3B NatA was constructed to compare the theoretical structure of this compound with the structures of previously reported proteins belonging to the bacterial GCN5 N-acetyltransferase family.

Bacillus subtilis IolQ (DegA) is a transcriptional repressor of iolX encoding NAD-dependent scyllo-inositol dehydrogenase.

Background: Bacillus subtilis is able to utilize at least three inositol stereoisomers as carbon sources, myo-, scyllo-, and D-chiro-inositol (MI, SI, and DCI, respectively). NAD-dependent SI dehydrogenase responsible for SI catabolism is encoded by iolX. Even in the absence of functional iolX, the presence of SI or MI in the growth medium was found to induce the transcription of iolX through an unknown mechanism.

Early pulmonary response is critical for extra-pulmonary carbon nanoparticle mediated effects: comparison of inhalation versus intra-arterial infusion exposures in mice.

Background: The death toll associated with inhaled ambient particulate matter (PM) is attributed mainly to cardio-vascular rather than pulmonary effects. However, it is unclear whether the key event for cardiovascular impairment is particle translocation from lung to circulation (direct effect) or indirect effects due to pulmonary particle-cell interactions. In this work, we addressed this issue by exposing healthy mice via inhalation and intra-arterial infusion (IAI) to carbon nanoparticles (CNP) as surrogate for soot, a major constituent of (ultrafine) urban PM.