In vivo monitoring of intracellular expression of human interleukin-2 using green fluorescent protein fusion partner in Pichia pastoris

The use of Pichia pastoris for protein production was simplified by creation of fusion proteins containing green fluorescent protein (GFP) and the product of interest. Human interleukin-2 (hIL-2) was used as a model product: GFP enabled clear identification of fusion protein expression and, more importantly, the quantification of hIL-2. Although GFP fusions for bioprocess monitoring have been demonstrated in other hosts, this is its first use in P. pastoris.     

Circle ligation of in vitro assembled chromatin indicates a highly flexible structure

Evidence is provided that some condensed linker histone-containing chromatin structures are highly flexible in solutions containing 2 mM Mg²⁺. Chromatin assembled in vitro ± histone H5 on a 6.3 kb linear DNA fragment in 90 mM NaCl using the polyglutamic acid method sedimented fairly homogeneously. The H5-containing sample had s_{20, w} values that were 58–69% greater than the sample lacking H5. Chromatin assembled on linear pUC19 plasmid DNA was treated with T4 DNA ligase in solutions containing 2 mM Mg²⁺ over a range of DNA concentrations. It was found that the intramolecular DNA ends of the chromatin could be joined together more efficiently than the intramolecular ends of the naked DNA at the higher DNA concentrations. This result could not be attributed to the effective reduction in DNA length by nucleosome formation. The chromatin structures formed did not have naked DNA tails extending from the ends as assessed by exonuclease III digestion. Chromatin assembled on DNA shortened by up to 420 bp gave very similar results, suggesting that the structure was a flexible one, rather than a rigid one having DNA ends that were fortuitously juxtaposed.     

Spatial regulation of DELTA expression mediates NOTCH signalling for segmentation of Drosophila legs.

The Notch (N) signalling pathway is recruited for segregation of cell fates in a number of Drosophila tissue types. We show here that N dependent segmentation of Drosophila legs is regulated by a dynamic pattern of expression of its ligand, DELTA (DL). During third larval instar and early stages of pupation, high levels of DL expression is seen in stripes of cells in the leg imaginal discs which later form the proximal borders of leg joints. These domains also displayed heightened Dl enhancer activity. During subsequent stages of pupation, following segmentation of the leg primordium, DL expression becomes uniform throughout these segments barring the joints. We further show that regulatory Dl mutations or mis-expression of DL abolish leg segmentation. Domains of N signalling for segmentation of legs of flies are thus set up by a stringent spatial regulation of expression of its ligand at the segment border. Further, a comparable role of DL in antennal development reveals a common paradigm of DL-N signalling for segmentation of appendages in flies.     

Additive multiple predator effects can reduce mosquito populations

1. Multiple predator interactions may profoundly alter ecological community dynamics and can complicate predictions of simpler pairwise predator–prey interaction strengths. In particular, multiple predator effects may lessen or enhance prey risk, with implications for community-level stability. Such emergent effects may modulate natural enemy efficacy towards target organisms. 2. In the present study, a functional response approach was used to quantify emergent multiple predator effects among natural enemies towards the disease vector mosquito complex, Culex pipiens. Conspecific multiple predator–predator interactions of the cyclopoid copepod Macrocyclops albidus (intermediate predator) were quantified by comparing multiple predator consumption simulations, based on individual consumption rates, with multiple predator consumption rates that were experimentally observed. Further, the study examined the influence of the presence of a predator at a higher trophic level, Chaoborus flavicans, on copepod group predation. 3. Both predators displayed type II functional responses, with C. flavicans consuming significantly more prey than M. albidus individually. Overall consumption levels of mosquitoes increased with greater predator density and richness. Antagonistic or synergistic emergent multiple predator effects between conspecifics of M. albidus were not detected, and the higher-level predator did not reduce effects of the intermediate predator. Accordingly, evidence for additive multiple predator interactions was found. 4. The lack of predator–predator interference between cyclopoid copepods and larval chaoborid midges provides strong support for their combined application in mosquito biocontrol. It is proposed that there should be increased examination of multiple predator effects in assessments of natural enemy efficacies to better understand overall predatory effects within communities and utilities in vector control.     

高等植物中的磷酸烯醇式丙酮酸羧激酶

简要介绍了近年来有关高等植物中磷酸烯醇式丙酮酸羧激酶（ＰＥＰＣＫ）的研究进展,并讨论了此酶的结构、功能和调节等方面的问题。     

The Association between Health System Development and the Burden of Cardiovascular Disease: An Analysis of WHO Country Profiles

Background

Several risk factors for cardiovascular disease (CVD) have been identified in recent decades. However, the association between the health system and the burden of CVD has not yet been sufficiently researched. The objective of this study was to analyse the association between health system development and the burden of CVD, in particular CVD-related disability-adjusted life–years (DALYs).

Methods

Univariate and multivariate generalized linear mixed models were applied to country-level data collected by the World Bank and World Health Organization. Response variables were the age-standardized CVD mortality and age-standardized CVD DALY rates.

Results

The amount of available health system resources, indicated by total health expenditures per capita, physician density, nurse density, dentistry density, pharmaceutical density and the density of hospital beds, was associated with reduced CVD DALY rates and CVD mortality. However, in the multivariate models, the density of nurses and midwives was positively associated with CVD. High out-of-pocket costs were associated with increased CVD mortality in both univariate and multivariate analyses.

Conclusion

A highly developed health system with a low level of out-of-pocket costs seems to be the most appropriate to reduce the burden of CVD. Furthermore, an efficient balance between human health resources and health technologies is essential.     

Cytoplasmic Localization of Human cdc25C during Interphase Requires an Intact 14-3-3 Binding Site

cdc25C induces mitosis by activating the cdc2-cyclin B complex. The intracellular localization of cyclin B1 is regulated in a cell cycle-specific manner, and its entry into the nucleus may be required for the initiation of mitosis. To determine the cellular localization of cdc25C, monoclonal antibodies specific for cdc25C were developed and used to demonstrate that in human cells, cdc25C is retained in the cytoplasm during interphase. A deletion analysis identified a 58-amino-acid region (amino acids 201 to 258) in cdc25C that was required for the cytoplasmic localization of cdc25C. This region contained a specific binding site for 14-3-3 proteins, and mutations in cdc25C that disrupted 14-3-3 binding also disrupted the cytoplasmic localization of cdc25C during interphase. cdc25C proteins that do not contain a binding site for 14-3-3 proteins showed a pancellular localization and an increased ability to induce premature chromosome condensation. The cytoplasmic localization of cdc25C was not altered by gamma irradiation or treatment with the nuclear export inhibitor leptomycin B. These results suggest that 14-3-3 proteins may negatively regulate cdc25C function by sequestering cdc25C in the cytoplasm.     

Gaining Perspective on What We've Lost: The Reliability of Encoded Anecdotes in Historical Ecology

Historical data are essential in fisheries management and conservation, especially for species that suffered significant population declines prior to ecological data collection. Within the field of historical marine ecology, studies have relied on anecdotal evidence, such as written accounts by explorers and interviews of different generations of resource users, to demonstrate the former abundance of certain species and the extent of their ranges. Yet, do we all agree on how these anecdotes are interpreted? This study examines the way that different people interpret anecdotes extracted from historical narratives. We outsource a survey to 50 randomly selected people using Amazon Mechanical Turk (www.mturk.com) and ask them to ‘code’ historical anecdotes based on their perceived abundance of species. We perform intercoder reliability tests to show that people''s perceptions of historical anecdotes are generally consistent. The results speak to the reliability of using people''s perceptions to acquire quantitative data, and provide novel insights into the use of anecdotal evidence to inform historical ecology.