Disruption of Trichoderma reesei cre2, encoding an ubiquitin C-terminal hydrolase, results in increased cellulase activity

The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1472-6750/11/103Background: The filamentous fungus Trichoderma reesei (Hypocrea jecorina) is an important source of cellulases for use in the textile and alternative fuel industries. To fully understand the regulation of cellulase production in T. reesei, the role of a gene known to be involved in carbon regulation in Aspergillus nidulans, but unstudied in T. reesei, was investigated. Results: The T. reesei orthologue of the A. nidulans creB gene, designated cre2, was identified and shown to be functional through heterologous complementation of a creB mutation in A. nidulans. A T. reesei strain was constructed using gene disruption techniques that contained a disrupted cre2 gene. This strain, JKTR2-6, exhibited phenotypes similar to the A. nidulans creB mutant strain both in carbon catabolite repressing, and in carbon catabolite derepressing conditions. Importantly, the disruption also led to elevated cellulase levels. Conclusions: These results demonstrate that cre2 is involved in cellulase expression. Since the disruption of cre2 increases the amount of cellulase activity, without severe morphological affects, targeting creB orthologues for disruption in other industrially useful filamentous fungi, such as Aspergillus oryzae, Trichoderma harzianum or Aspergillus niger may also lead to elevated hydrolytic enzyme activity in these species.Jai A Denton and Joan M Kell

C-reactive protein haplotypes and dispositional optimism in obese and nonobese elderly subjects

Background Chronic low-grade inflammation, characterized by elevated plasma levels of C-reactive protein (CRP), has been inversely associated with dispositional optimism. Using a Mendelian randomization design, this study explores whether CRP haplotypes that determine CRP plasma levels are also associated with dispositional optimism. Methods In a sample of 1,084 community-dwelling subjects (aged 60–85 years) from three cohort studies (Arnhem Elderly Study, n = 426; Leiden Longevity Study, n = 355; Zutphen Elderly Study, n = 303), six CRP polymorphisms (rs2808628, rs2808630, rs1205, rs1800947, rs1417938, and rs3091244) coding for five common haplotypes were genotyped. The association of CRP haplotypes with CRP plasma levels and dispositional optimism was analyzed using multivariable linear regression models. Subanalyses were stratified by body mass index (BMI =25 kg/m2). Results CRP haplotypes determined CRP plasma levels (adjusted ß = 0.094, p <0.001). In the whole group, no association was found between CRP haplotypes and dispositional optimism scores (adjusted ß = -0.02, p = 0.45). In BMI strata, CRP haplotypes were associated with increasing levels of plasma CRP levels (adjusted ß = 0.112; p = 0.002) and lower dispositional optimism levels (adjusted ß = -0.068; p = 0.03) in the obese group only. Conclusions These results suggest that genetically increased CRP levels are involved in low dispositional optimism, but only in case of obesit