Interactive effects of shade and surface orientation on the recruitment of spirorbid polychaetes

A series of observations and an experiment were carried out to test hypotheses about the effects of shade on the densities of spirorbid polychaetes (Neodexiospira spp.) on intertidal pneumatophores (mangrove roots) of Avicennia marina. Densities of spirorbids were greater on pneumatophores surrounded by seagrass (Zostera mucronata) than patches without seagrass. Within patches of seagrass, the density and survivorship of spirorbids on pneumatophores was greater near the substratum (covered by seagrass) than high above the substratum (not covered by seagrass). The model that these patterns of abundance are explained by greater recruitment of spirorbids to shaded surfaces was assessed. This was done by experimentally testing the hypothesis that recruitment to patches without seagrass would not differ between the upper (unshaded) and lower surfaces (unshaded) of clear plastic sheets, but would be greater on the lower surfaces (shaded) than upper surfaces (unshaded) of black plastic sheets. Recruitment was consistent with these predictions and therefore provided evidence that differences in densities of spirorbids between substrata with and without seagrass may be due largely to differences in shading.     

Drosophila melanogaster glutamate-cysteine ligase activity is regulated by a modifier subunit with a mechanism of action similar to that of the mammalian form.

Glutamate-cysteine ligase (GCL) plays an important role in regulating glutathione homeostasis. In mammals, it comprises a catalytic (GCLC) and modifier (GCLM) subunit. The existence of a modifier subunit in invertebrates has not been described to date. We now demonstrate that GCL from Drosophila melanogaster has a functional modifier subunit (DmGCLM). A putative DmGCLM was obtained as an expressed sequence tag with 27% identity to human GCLM at the amino acid level. D. melanogaster GCLC (DmGCLC) and the candidate DmGCLM were expressed separately in Escherichia coli, purified, mixed, and then subjected to gel filtration, where they eluted as an approximately 140-kDa complex. DmGCLC co-immunoprecipitated with DmGCLM from S2 cell extracts, suggesting that they also associate in vivo. Enzyme kinetic analyses showed that DmGCLC has a K(m) for glutamate of 2.88 mm, but when complexed with DmGCLM, the K(m) for glutamate is 0.45 mm. Inhibition of DmGCLC activity by glutathione was found to be competitive with respect to glutamate (K(i) = 0.03 mm), whereas inhibition of the GCL complex was mixed (K(i) = 0.67 mm), suggesting allosteric effects. In accordance with this, DmGCLC and DmGCLM have the ability to form reversible intermolecular disulfide bridges. A further mechanism for control of D. melanogaster GCL was found to be induction of DmGCLC by tert-butylhydroquinone in S2 cells. DmGCLM levels were, however, unaffected by tert-butylhydroquinone.     

Dynamic regulation of cyclooxygenase-2 promoter activity by isoforms of CCAAT/enhancer-binding proteins.

To elucidate the mechanism by which isoforms of CCAAT/enhancer-binding proteins regulate cyclooxygenase-2 expression, we determined by a novel technique binding of six isoforms of this transactivator to two sequence-specific CCAAT/enhancer-binding protein (-132/-125) and cyclic AMP (-59/-53) regulatory elements in human foreskin fibroblasts treated with phorbol 12-myristate 13-acetate for 4 h. The delta isoform bound to these two elements at basal state, which was displaced by full-length as well as two truncated beta isoforms, a 41-kDa liver-enriched activating protein and a 16-kDa liver-enriched inhibitory protein, after phorbol ester stimulation. Kinetic analysis shows time-dependent changes in beta and delta binding that were concordant with time-dependent increase in cyclooxygenase-2 induction. Overexpression of the 16-kDa beta isoform blocked the promoter activity and protein level induced by phorbol ester. Paradoxically, it increased binding of beta isoforms to the sequence-specific promoter DNA but suppressed cyclooxygenase-2 promoter activation by p300 cotransfection. These findings provide new insight into the regulation of cyclooxygenase-2 promoter by an interplay between two opposite beta isoforms and p300 co-activator.     

Impact on survival of intensive follow up after curative resection for colorectal cancer: systematic review and meta-analysis of randomised trials

ObjectiveTo review the evidence from clinical trials of follow up of patients after curative resection for colorectal cancer.DesignSystematic review and meta-analysis of randomised controlled trials of intensive compared with control follow up.ResultsFive trials, which included 1342 patients, met the inclusion criteria. Intensive follow up was associated with a reduction in all cause mortality (combined risk ratio 0.81, 95% confidence interval 0.70 to 0.94, P=0.007). The effect was most pronounced in the four extramural detection trials that used computed tomography and frequent measurements of serum carcinoembryonic antigen (risk ratio 0.73, 0.60 to 0.89, P=0.002). Intensive follow up was associated with significantly earlier detection of all recurrences (difference in means 8.5 months, 7.6 to 9.4 months, P<0.001) and an increased detection rate for isolated local recurrences (risk ratio 1.61, 1.12 to 2.32, P=0.011).ConclusionsIntensive follow up after curative resection for colorectal cancer improves survival. Large trials are required to identify which components of intensive follow up are most beneficial.

What is already known on this topic

There is a lack of direct evidence that intensive follow up after initial curative treatment for colorectal cancer leads to increased survivalGuidelines are inconclusive and clinical practice varies widely

What this study adds

The cumulative analysis of available data supports the view that intensive follow up after curative resection for colorectal cancer improves survivalIf computed tomography and frequent measurements of serum carcinoembryonic antigen are used during follow up mortality related to cancer is reduced by 9-13%This survival benefit is partly attributable to the earlier detection of all recurrences, particularly the increased detection of isolated recurrent disease     

Improving the pharmacokinetic properties of biologics by fusion to an anti-HSA shark VNAR domain

Advances in recombinant antibody technology and protein engineering have provided the opportunity to reduce antibodies to their smallest binding domain components and have concomitantly driven the requirement for devising strategies to increase serum half-life to optimise drug exposure, thereby increasing therapeutic efficacy. In this study, we adopted an immunization route to raise picomolar affinity shark immunoglobulin new antigen receptors (IgNARs) to target human serum albumin (HSA). From our model shark species, Squalus acanthias, a phage display library encompassing the variable binding domain of IgNAR (VNAR) was constructed, screened against target, and positive clones were characterized for affinity and specificity. N-terminal and C-terminal molecular fusions of our lead hit in complex with a naïve VNAR domain were expressed, purified and exhibited the retention of high affinity binding to HSA, but also cross-selectivity to mouse, rat and monkey serum albumin both in vitro and in vivo. Furthermore, the naïve VNAR had enhanced pharmacokinetic (PK) characteristics in both N- and C-terminal orientations and when tested as a three domain construct with naïve VNAR flanking the HSA binding domain at both the N and C termini. Molecules derived from this platform technology also demonstrated the potential for clinical utility by being available via the subcutaneous route of delivery. This study thus demonstrates the first in vivo functional efficacy of a VNAR binding domain with the ability to enhance PK properties and support delivery of multifunctional therapies.     

Focal Plant Observations as a Standardised Method for Pollinator Monitoring: Opportunities and Limitations for Mass Participation Citizen Science

BackgroundRecently there has been increasing focus on monitoring pollinating insects, due to concerns about their declines, and interest in the role of volunteers in monitoring pollinators, particularly bumblebees, via citizen science.

Methodology / Principal Findings

The Big Bumblebee Discovery was a one-year citizen science project run by a partnership of EDF Energy, the British Science Association and the Centre for Ecology & Hydrology which sought to assess the influence of the landscape at multiple scales on the diversity and abundance of bumblebees. Timed counts of bumblebees (Bombus spp.; identified to six colour groups) visiting focal plants of lavender (Lavendula spp.) were carried out by about 13 000 primary school children (7–11 years old) from over 4000 schools across the UK. 3948 reports were received totalling 26 868 bumblebees. We found that while the wider landscape type had no significant effect on reported bumblebee abundance, the local proximity to flowers had a significant effect (fewer bumblebees where other flowers were reported to be >5m away from the focal plant). However, the rate of mis-identifcation, revealed by photographs uploaded by participants and a photo-based quiz, was high.

Conclusions / Significance

Our citizen science results support recent research on the importance of local flocal resources on pollinator abundance. Timed counts of insects visiting a lure plant is potentially an effective approach for standardised pollinator monitoring, engaging a large number of participants with a simple protocol. However, the relatively high rate of mis-identifications (compared to reports from previous pollinator citizen science projects) highlights the importance of investing in resources to train volunteers. Also, to be a scientifically valid method for enquiry, citizen science data needs to be sufficiently high quality, so receiving supporting evidence (such as photographs) would allow this to be tested and for records to be verified.