Glucose kinase of Streptomyces coelicolor A3(2): large-scale purification and biochemical analysis

Glucose kinase of Streptomyces coelicolor A3(2) is essential for glucose utilisation and is required for carbon catabolite repression (CCR) exerted through glucose and other carbon sources. The protein belongs to the ROK-family, which comprises bacterial sugar kinases and regulators. To better understand glucose kinase function, we have monitored the cellular activity and demonstrated that the choice of carbon sources did not significantly change the synthesis and activity of the enzyme. The DNA sequence of the Streptomyces lividans glucose kinase gene glkA was determined. The predicted gene product of 317 amino acids was found to be identical to S. coelicolor glucose kinase, suggesting a similar role for this protein in both organisms. A procedure was developed to produce pure histidine-tagged glucose kinase with a yield of approximately 10 mg/l culture. The protein was stable for several weeks and was used to raise polyclonal antibodies. Purified glucose kinase was used to explore protein-protein interaction by surface plasmon resonance. The experiments revealed the existence of a binding activity present in S. coelicolor cell extracts. This indicated that glucose kinase may interact with (an)other factor(s), most likely of protein nature. A possible cross-talk with proteins of the phosphotransferase system, which are involved in carbon catabolite repression in other bacteria, was investigated.     

Genomic structure and fine mapping of the two human filamin gene paralogues FLNB and FLNC and comparative analysis of the filamin gene family

The genomic structure of the filamin gene paralogues FLNB and FLNC was determined and related to FLNA. FLNB consists of 45 exons and 44 introns and spans approximately 80 kb of genomic DNA. FLNC is divided into 48 exons and 47 introns and covers approximately 29.5 kb of genomic DNA. A previously unknown intron was found in FLNA. The comparison of all three filamin gene paralogues revealed a highly conserved exon-intron structure with significant differences in the exons 32 of all paralogues encoding the hinge I region, as well as the insertion of a novel exon 40A in FLNC only. Gene organization does not correlate with the domain structures of the respective proteins. To improve candidate gene cloning approaches, FLNB was precisely mapped at 3p14 in an interval of 0.81 cM between WI3771 and WI6691 and FLNC at 7q32 in an interval of 2.07 cM between D7S530 and D7S649.     

Body odor evoked potentials: a new method to study the chemosensory perception of self and non‐self in humans

A new method will be presented which allows the perception of body odors in humans to be studied objectively. The analysis of body odor‐evoked potentials was used to investigate if and how the human brain is able to differentiate self from non‐self body odor for the first time. Six subjects (three females) participated in two experimental sessions. In each session, two body odors (axillary hair) were presented within an olfactory oddball paradigm. One of the odors was collected from the subject and the other from an odor donor of the same sex. In the first session the subjects' attention was distracted to a secondary task (passive paradigm), in the second session the subjects were asked to actively differentiate the odors (active paradigm). For the EEG recordings the odors were presented within a constantly flowing airstream. The results show that the subjects could hardly differentiate the body odors subjectively. However, it could be demonstrated that the central nervous processing of one's own odor was faster than the processing of the chemosensory non‐self signal. Moreover, in the active paradigm, the potentials appeared to be larger when the subjects perceived their own body odor. The conclusion is reached that the measurement of chemosensory event‐related potentials (CSERP) is the method of choice for the investigation of HLA‐associated body odors. This revised version was published online in July 2006 with corrections to the Cover Date.     

A Cytopathogenic, Apoptosis-Inducing Variant of Hepatitis A Virus

A cytopathogenic variant of hepatitis A virus (HAV_cyt/HB1.1) was isolated from persistently infected BS-C-1 cells by serial passages in FRhK-4 cells. This virus shows a rapid replication pattern and high final titers are obtained, which are main characteristics of cytopathogenic HAVs. Sequencing of the nontranslated regions and the coding regions for 2ABC and 3AB revealed that mutations are distributed all over these regions and that certain mutated sites correspond to those in other cytopathogenic HAV variants. Investigating the mechanisms causing the cytopathic effect in FRhK-4 cells infected with this variant, we found that an apoptotic reaction takes place.     

Heteronuclear correlation experiments for the determination of one-bond coupling constants

Spin-state selective experiments, HSQC-/ and CT-HMQC-/, are proposed for the simple and rapid measurement of scalar one-bond coupling constants in two-dimensional,¹ H-detected ¹⁵N-¹H or¹³ C-¹H correlation experiments based on HSQC and HMQC schemes. Pairs of subspectra are obtained, containing either the high-field or the low-field component of the doublet representing the one-bond coupling constant. The subspectral editing procedure retains the full sensitivity of HSQC and HMQC spectra recorded without heteronuclear decoupling during data acquisition, with a spectral resolution similar to that of decoupled spectra.     

Homology of Hox Genes and the Zootype Concept in Early Metazoan Evolution

The correct identification of homologous Hox genes within and between diplo- and triploblastic animals is of crucial importance for recent hypotheses on the anagenetic evolution of animal bauplans. While the homology discussion in general has reached new heights, we apply traditional homology criteria to assign homology to Hox genes from diploblastic animals. Comparison of theTrox-2gene from the presumably most basal metazoan animal, the placozoanTrichoplax adhaerens,to other Hox genes suggests the presence of unambiguous homologs in Hydrozoa and Scyphozoa and the absence of any specific homolog in triploblasts. Furthermore, the comparisons provide support for the idea that Hox genes—at least in diploblastic animals—are composed of functional subunits (modules), which to some degree have undergone independent evolution. The findings are not readily compatible with the existence of the “zootype” in diploblastic animals.     

The Prognostic Value of the Work Ability Index for Sickness Absence among Office Workers

BackgroundThe work ability index (WAI) is a frequently used tool in occupational health to identify workers at risk for a reduced work performance and for work-related disability. However, information about the prognostic value of the WAI to identify workers at risk for sickness absence is scarce.ObjectivesTo investigate the prognostic value of the WAI for sickness absence, and whether the discriminative ability differs across demographic subgroups.MethodsAt baseline, the WAI (score 7-49) was assessed among 1,331 office workers from a Dutch financial service company. Sickness absence was registered during 12-months follow-up and categorised as 0 days, 0<days<5, 5≤days<15, and ≥15 days in one year. Associations between WAI and sickness absence were estimated by multinomial regression analyses. Discriminative ability of the WAI was assessed by the Area Under the Curve (AUC) and Ordinal c-index (ORC). Test characteristics were determined for dichotomised outcomes. Additional analyses were performed for separate WAI dimensions, and subgroup analyses for demographic groups.ResultsA lower WAI was associated with sickness absence (≥15 days vs. 0 days: per point lower WAI score OR=1.27; 95%CI 1.21-1.33). The WAI showed reasonable ability to discriminate between categories of sickness absence (ORC=0.65; 95%CI 0.63-0.68). Highest discrimination was found for comparing workers with ≥15 sick days with 0 sick days (AUC=0.77) or with 1-5 sick days (AUC=0.69). At the cut-off for poor work ability (WAI≤27) the sensitivity to identify workers at risk for ≥15 sick days was 7.5%, the specificity 99.6%, and the positive predictive value 82%. The performance was similar across demographic subgroups.ConclusionsThe WAI could be used to identify workers at high risk for prolonged sickness absence. However, due to low sensitivity many workers will be missed. Hence, additional factors are required to better identify workers at highest risk.