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Brevibacillus thermoruber strain Nabari cells grow as widely spreading dendritic colonies on reasoner's 2A‐agar (1.5%) plates at around 55°C but as small motile colonies at 37°C. Motile colonies can be divided into colonies that move in straight or curved lines over long distances (wandering colonies), and colonies that rotate at a fixed location (rotating colonies). The addition of surfactant to the agar medium greatly increased the frequency of wandering colonies and facilitated the study of such colonies. The morphology of the wandering colonies varied: circular at the tip and pointed at the back, lemon‐shaped with pointed ends, crescent‐shaped, bullet‐shaped, fish‐like, and so on. A single colony may split into multiple colonies as it moves, or multiple colonies may merge into a single colony. The most surprising aspect of the movement of wandering colonies was that when a moving colony collides with another colony, it sometimes does not make a U‐turn, but instead retreats straight back, as if bouncing back. The migration mechanisms of wandering colonies are discussed based on optical microscopic observations of swimming patterns of single cells in water and scanning electron microscopy of the arrangement of bacterial cells in wandering colonies. [ABSTRACT FROM AUTHOR]

Brevibacillus thermoruber strain Nabari was isolated from compost and identified based on 16 S rRNA gene sequencing and DNA–DNA hybridization using B. thermoruber DSM 7064 T as the standard, despite some differences in their physiological and structural characteristics. When B. thermoruber Nabari was cultivated on various solid media containing 1.5% agar at 60°C, it rapidly propagated over the entire plate. In particular, on R2A‐agar medium, it formed fine dendritic colonies. Macroscopic and microscopic observations of peripheral regions of the colonies indicated that the dendritic patterns were formed by bacterial swarming of some of the cells; large flows of bacterial cell populations were observed in the peripheral regions of the dendritic colonies. The cells were highly flagellated, but no extreme elongation of cells was observed. When B. thermoruber Nabari cells were cultivated at 37°C on R2A‐agar plates, most colonies were nonmotile, but some colonies were motile. For example, a wandering colony moved on the plate and split into two, and then they collided to become one again. Additionally, a simple incubation system was devised to record the movement of colonies at high temperatures in this study while protecting the cameras from thermal damage. [ABSTRACT FROM AUTHOR]

Laminin_G_3 modules can exist together with family‐43 catalytic modules of glycoside hydrolase (GH43), but their functions are unknown. Here, a laminin_G_3 module and a GH43 module derived from a Ruminiclostridium josui modular arabinofuranosidase Abf43A‐Abf43B‐Abf43C were produced individually as RjLG3 and RjGH43_22, respectively, or combined as RjGH43‐1 to gain insights into their activities. Isothermal calorimetry analysis showed that RjLG3 has high affinity toward 32‐α‐l‐arabinofuranosyl‐(1,5)‐α‐l‐arabinotriose but not for α‐1,5‐linked arabinooligosaccharides, which suggests that RjLG3 interacts specifically with a branched arabinofuranosyl residue of an arabinooligosaccharide but not an arabinofuranosyl residue at the end of α‐1,5‐linked arabinooligosaccharides. RjGH43‐1 (with CBM) shows higher activity toward sugar beet arabinan than RjGH43_22 (without CBM), which suggests that the LG3 module in RjGH43‐1 plays an important role in substrate hydrolysis as a carbohydrate‐binding module. [ABSTRACT FROM AUTHOR]

Although Ruminiclostridium josui (formerly Clostridium josui), a strictly anaerobic mesophilic cellulolytic bacterium, is a promising candidate for biomass utilization via consolidated bioprocessing, its host‐vector system has not yet been established. The existence of a restriction and modification system is a significant barrier to the transformation of R. josui. Here, we partially purified restriction endonuclease RjoI from R. josui cell extract using column chromatography. Further characterization showed that RjoI is an isoschizomer of DpnI, recognizing the sequence 5′‐GmetATC‐3′, where the A nucleotide is Dam‐methylated. RjoI cleaved the recognition sequence between the A and T nucleotides, producing blunt ends. We then successfully introduced plasmids prepared from Escherichia coli C2925 (dam−/dcm−) into R. josui by electroporation. The highest transformation efficiency of 6.6 × 103 transformants/μg of DNA was obtained using a square‐wave pulse (750 V, 1 ms). When the R. josui cel48A gene, devoid of the dockerin‐encoding region, cloned into newly developed plasmid pKKM801 was introduced into R. josui, a truncated form of RjCel48A, RjCel48AΔdoc, was detected in the culture supernatant but not in the intracellular fraction. This is the first report on the establishment of fundamental technology for molecular breeding of R. josui. [ABSTRACT FROM AUTHOR]

The newly isolated Paenibacillus sp. M33 from freshwater swamp forest soil in Thailand demonstrated its potential as a cellulose degrader. One of its endoglucanase genes from Paenibacillus sp., celP, was cloned to study the molecular characteristics of its gene product. The celP gene was recognized firstly by degenerate primer designed from Paenibacillus endoglucanase gene, and subsequently identified flanking region by inverse PCR technique. The celP gene consists of an open reading frame of 1707 bp encoding for 569 amino acids including 33-amino acids signal sequence. CelP is a member of glycoside hydrolase family 5 appended with a family 46 carbohydrate-binding module. CelP from recombinant Escherichia coli was purified by affinity chromatography. SDS-PAGE analysis of purified CelP showed a protein band at about 60 kDa. The purified enzyme gave a specific CMCase activity of 0.03 μmol min−1 mg−1. It had higher activities on lichenan (0.19 μmol min−1 mg−1) and barley β-glucan (0.14 μmol min−1 mg−1). Maximum activity on lichenan was obtained at 50 °C, pH 5.0. CelP was stable over a pH range of 3.0-10.0 and retained 80% activity when incubated at 50 °C for 1 h. The properties of its CelP endoglucanase, especially substrate specificity, will make it useful in various biotechnological applications including biomass hydrolysis. [ABSTRACT FROM AUTHOR]

Plant cell-wall polysaccharides offer an abundant energy source utilized by many microorganisms, thus playing a central role in carbon recycling. Aerobic microorganisms secrete carbohydrate-active enzymes (CAZymes) that catabolize this composite structure, comprising cellulose, hemicellulose and lignin, into simple compounds such as glucose. Carbohydrate-binding modules (CBMs) enhance the efficacy of associated CAZYmes. They are organized into families based on primary-sequence homology. CBM family 46 contains more than 40 different members, but has yet to be fully characterized. Here, a recombinant derivative of the C-terminal family 46 CBM module ( BhCBM46) of Bacillus halodurans endo-β-1,4-glucanase B (CelB) was overexpressed in Escherichia coli and purified by immobilized metal-ion affinity chromatography. Preliminary structural characterization was carried out on BhCBM46 crystallized in different conditions. The crystals of BhCBM46 belonged to the tetragonal space group I4122. Data were collected for the native form and a selenomethionine derivative to 2.46 and 2.3 Å resolution, respectively. The BhCBM46 structure was determined by a single-wavelength anomalous dispersion experiment using AutoSol from the PHENIX suite. [ABSTRACT FROM AUTHOR]

Highlights: [•] An essential role of a CBM in substrate recognition by mannanase CtMan5A is reported. [•] A catalytic domain and a CBM collectively form a substrate-binding site. [•] The CBM directly participates in substrate recognition for catalytic action. [•] CtMan5A and its derivative without the CBM yielded different hydrolysis products. [•] Substrate binding modes of CtMan5A and the truncated derivative are different. [Copyright &y& Elsevier]

Clostridium stercorarium Xyn10B is a modular enzyme comprising two family-22 carbohydrate-binding modules (CBMs), a family-10 catalytic module of glycoside hydrolases, a family-9 CBM, and two S-layer homologous modules consecutively from the N-terminus. To investigate the role of the family-22 CBMs, truncated proteins were constructed: a recombinant catalytic module polypeptide (rCD), a CBM polypeptide composed of two family-22 CBMs (rCBM) and a polypeptide composed of the family-22 CBMs and the catalytic module (rCBM-CD). We found that rCBM-CD was highly active toward β-1,3-1,4-glucan; however, rCD was negligibly active toward the same substrate. The Vmax/Km value of rCBM-CD for β-1,3-1,4-glucan was 7.8 times larger than that for oat-spelt xylan, indicating that rCBM-CD should be specified as a β-1,3-1,4-glucanase rather than a xylanase despite the fact that family-10 catalytic modules are well-known xylanase modules. These results indicate that the family-22 CBMs in rCBM-CD are essential for hydrolysis of β-1,3-1,4-glucan. [Copyright &y& Elsevier]

Cellulases catalyze the hydrolysis of cellulose, the major constituent of plant biomass and the most abundant organic polymer on earth. Cellulases are modular enzymes containing catalytic domains connected, via linker sequences, to noncatalytic carbohydrate-binding modules (CBMs). A putative modular endo-β-1,4-glucanase ( BhCel5B) is encoded at locus BH0603 in the genome of Bacillus halodurans. It is composed of an N-terminal glycoside hydrolase family 5 catalytic module (GH5) followed by an immunoglobulin-like module and a C-terminal family 46 CBM ( BhCBM46). Here, the crystallization and preliminary X-ray diffraction analysis of the trimodular BhCel5B are reported. The crystals of BhCel5B belonged to the orthorhombic space group P2121 2 and data were processed to a resolution of 1.64 Å. A molecular-replacement solution has been found. [ABSTRACT FROM AUTHOR]

Studies the crystallization and preliminary X-ray analysis of xylanase B from Clostridium stercorarium. Preparation of the expression plasmid and the recombinant enzyme; Growth of a suitable crystal after incubation for ten weeks at 293 K.