Although a lot of xylanases are studied, only a few xylanases from marine microorganisms have been reported. A new xylanase gene, xynA, was cloned from marine bacterium Glaciecola mesophila KMM 241. Gene xynA contains 1,272 bp and encodes a 423-amino acid xylanase precursor. The recombinant xylanase, XynA, expressed in Escherichia coli BL21 is a monomer with a molecular mass of 43 kDa. Among the characterized xylanases, XynA shares the highest identity (46%) to the xylanase from Flavobacterium sp. strain MSY2. The optimum pH and temperature for XynA is 7.0 and 30 degrees C. XynA retains 23% activity and 27% catalytic efficiency at 4 degrees C. XynA has low thermostability, remaining 20% activity after 60-min incubation at 30 degrees C. Its apparent melting temperature (T (m)) is 44.5 degrees C. These results indicate that XynA is a cold-active xylanase. XynA shows a high level of salt-tolerance, with the highest activity at 0.5 M NaCl and retaining 90% activity in 2.5 M NaCl. It may be the first salt-tolerant xylanase reported. XynA is a strict endo-beta-1,4-xylanase with a demand of at least four sugar moieties for effective cleavage. It efficiently hydrolyzes xylo-oligosaccharides and xylan into xylobiose and xylotriose without producing xylose, suggesting its potential in xylo-oligosaccharides production.

The first Cu-catalyzed asymmetric borylative cyclization of cyclohexadienone-containing 1,6-enynes is achieved through a tandem process: selective β-borylation of propargylic ether and subsequent conjugate addition to cyclohexadienone. The reaction proceeds with excellent regioselectivity and enantioselectivity to afford an optically pure cis-hydrobenzofuran framework bearing alkenylboronate and enone substructures. Furthermore, the resulting bicyclic products could be converted to bridged and tricyclic ring structures. This method extends the realm of Cu-catalyzed asymmetric tandem reactions using bis(pinacolato)diboron (B2pin2).

To evaluate a theory-guided intervention on oral self-care and examine the possible mechanisms among self-regulatory factors, two brief intervention arms were compared, an information-based education treatment and a self-regulation treatment focusing on planning and action control. Young adults (N = 284; aged 18-29 years) were assessed at baseline and 1 month later. The self-regulation intervention improved levels of oral self-care, dental planning and action control. Moreover, a moderated mediation model with planning as the mediator between experimental conditions and dental outcome, and self-efficacy as well as action control as moderators elucidated the mechanism of change. More self-efficacious participants in the self-regulation condition benefitted in terms of more planning, and those who monitored their actions yielded higher levels of oral hygiene. Dental self-efficacy, dental planning and action control are involved in the improvement of oral self-care. Their joint consideration may contribute to a better understanding of health behavior change.

Antibiosis is one of the widespread strategies used by Trichoderma spp. against plant fungal pathogens, the mechanism of which, however, remains poorly understood. Peptaibols are a large family of antimicrobial peptides produced by Trichoderma spp. Our previous study showed that trichokonins, a type of peptaibol from Trichoderma pseudokoningii SMF2, exhibited antibiotic activities against plant fungal pathogens. In this study, we first demonstrated that trichokonin VI (TK VI) induced extensive apoptotic programmed cell death in plant fungal pathogens. For a deeper insight into the apoptotic mechanism involved in the action of TK VI, Fusarium oxysporum was used as a model. Cells of F. oxysporum treated with TK VI showed apoptotic hallmarks, such as exposure of phosphatidylserine, the appearance of reactive oxygen species and fragmentation of nuclear DNA. Moreover, TK VI-treated cells exhibited an accumulation of cytoplasmic vacuoles with loss of the mitochondrial transmembrane potential, and this process was independent of metacaspases. Therefore, TK VI induces metacaspase-independent apoptotic cell death in F. oxysporum. This represents what is believed to be the first report to reveal the antibiotic mechanism of peptaibols against plant fungal pathogens. INTRODUCTIONSome Trichoderma species, such as Trichoderma harzianum, Trichoderma virens and Trichoderma viride, are commercial biological control agents (BCAs) against plant fungal pathogens (Chet & Inbar, 1994;Howell, 2003;Benítez et al., 2004). Trichoderma spp. act as BCAs through mycoparasitism, antibiosis, substrate competition, and production of antibiotics and cell wall-degrading enzymes (CWDEs) to inhibit the growth of fungal pathogens, promote plant growth and induce resistance in plants (Yedidia et al., 1999;Viterbo et al., 2005). Antibiosis is a widespread strategy used for defence by Trichoderma spp. (Pyke & Dietz, 1966;Whitmore & Wallace, 2004). Trichoderma spp. produce a variety of antibiotics, such as gliovirin, gliotoxin, viridin, pyrones and peptaibols, against fungal phytopathogens (Howell, 2003;Harman et al., 2004). However, among the reported biocontrol mechanisms of Trichoderma, very few studies have been done on their antibiotic mechanism.Peptaibols are a large family of antibiotic peptides from soil fungi, including Trichoderma and related genera such as Emericelopsis and Gliocladium (Daniel & Filho, 2007). To date, 317 peptaibols have been reported, and among them more than 190 are synthesized by Trichoderma. Details are compiled in the Peptaibol Database (http://www.cryst.bbk. ac.uk/peptaibol) (Whitmore & Wallace, 2004). Peptaibols are characterized by the presence of an unusual amino acid, a-aminoisobutyric acid (Aib), a C-terminal-hydroxylated and N-terminal-acetylated amino acid, and they are able to form voltage-dependent ion channels in lipid bilayer membranes because of their linear and amphipathic nature (Chugh & Wallace, 2001). Most research on peptaibols has focused on their biosynthetic pathways, conformational properties and a...