175 research outputs found
Phylogenetic Analysis of the Neks Reveals Early Diversification of Ciliary-Cell Cycle Kinases
NIMA-related kinases (Neks) have been studied in diverse eukaryotes, including the fungus Aspergillus and the ciliate Tetrahymena. In the former, a single Nek plays an essential role in cell cycle regulation; in the latter, which has more than 30 Neks in its genome, multiple Neks regulate ciliary length. Mammalian genomes encode an intermediate number of Neks, several of which are reported to play roles in cell cycle regulation and/or localize to centrosomes. Previously, we reported that organisms with cilia typically have more Neks than organisms without cilia, but were unable to establish the evolutionary history of the gene family
Deconstructing Insight: EEG Correlates of Insightful Problem Solving
Background:
Cognitive insight phenomenon lies at the core of numerous discoveries. Behavioral research indicates four salient features of insightful problem solving: (i) mental impasse, followed by (ii) restructuring of the problem representation, which leads to (iii) a deeper understanding of the problem, and finally culminates in (iv) an “Aha!” feeling of suddenness and obviousness of the solution. However, until now no efforts have been made to investigate the neural mechanisms of these constituent features of insight in a unified framework.
Methodology/Principal Findings:
In an electroencephalographic study using verbal remote associate problems, we identified neural correlates of these four features of insightful problem solving. Hints were provided for unsolved problems or after mental impasse. Subjective ratings of the restructuring process and the feeling of suddenness were obtained on trial-by-trial basis. A negative correlation was found between these two ratings indicating that sudden insightful solutions, where restructuring is a key feature, involve automatic, subconscious recombination of information. Electroencephalogram signals were analyzed in the space×time×frequency domain with a nonparametric cluster randomization test. First, we found strong gamma band responses at parieto-occipital regions which we interpreted as (i) an adjustment of selective attention (leading to a mental impasse or to a correct solution depending on the gamma band power level) and (ii) encoding and retrieval processes for the emergence of spontaneous new solutions. Secondly, we observed an increased upper alpha band response in right temporal regions (suggesting active suppression of weakly activated solution relevant information) for initially unsuccessful trials that after hint presentation led to a correct solution. Finally, for trials with high restructuring, decreased alpha power (suggesting greater cortical excitation) was observed in right prefrontal area.
Conclusions/Significance:
Our results provide a first account of cognitive insight by dissociating its constituent components and potential neural correlates
Comparison of Internal Ribosome Entry Site (IRES) and Furin-2A (F2A) for Monoclonal Antibody Expression Level and Quality in CHO Cells
10.1371/journal.pone.0063247PLoS ONE85
The Endocrine Disruptor Mono-(2-Ethylhexyl) Phthalate Affects the Differentiation of Human Liposarcoma Cells (SW 872)
Esters of phthalic acid (phthalates) are largely used in industrial plastics, medical devices, and pharmaceutical formulations. They are easily released from plastics into the environment and can be found in measurable levels in human fluids. Phthalates are agonists for peroxisome proliferator-activated receptors (PPARs), through which they regulate translocator protein (TSPO; 18 kDa) transcription in a tissue-specific manner. TSPO is a drug- and cholesterol-binding protein involved in mitochondrial respiration, steroid formation, and cell proliferation. TSPO has been shown to increase during differentiation and decrease during maturation in mouse adipocytes. The purpose of this study was to establish the effect of mono-(2-ethylhexyl) phthalate (MEHP) on the differentiation of human SW 872 preadipocyte cells, and examine the role of TSPO in the process. After 4 days of treatment with 10 µM MEHP, we observed changes in the transcription of acetyl-CoA carboxylase alpha, adenosine triphosphate citrate lyase, glucose transporters 1 and 4, and the S100 calcium binding protein B, all of which are markers of preadipocyte differentiation. These observed gene expression changes coincided with a decrease in cellular proliferation without affecting cellular triglyceride content. Taken together, these data suggest that MEHP exerts a differentiating effect on human preadipocytes. Interestingly, MEHP was able to temporarily increase TSPO mRNA levels through the PPAR-α and β/δ pathways. These results suggest that TSPO can be considered an important player in the differentiation process itself, or alternatively a factor whose presence is essential for adipocyte development
Association of urinary phthalate metabolite concentrations with body mass index and waist circumference: a cross-sectional study of NHANES data, 1999–2002
BACKGROUND: Although diet and activity are key factors in the obesity epidemic, laboratory studies suggest that endocrine disrupting chemicals may also affect obesity. METHODS: We analyzed associations between six phthalate metabolites measured in urine and body mass index (BMI) and waist circumference (WC) in National Health and Nutrition Examination Survey (NHANES) participants aged 6–80. We included 4369 participants from NHANES 1999–2002, with data on mono-ethyl (MEP), mono-2-ethylhexyl (MEHP), mono-n-butyl (MBP), and mono-benzyl (MBzP) phthalate; 2286 also had data on mono-2-ethyl-5-hydroxyhexyl (MEHHP) and mono-2-ethyl-5-oxohexyl (MEOHP) phthalate (2001–2002). Using multiple regression, we computed mean BMI and WC within phthalate quartiles in eight age/gender specific models. RESULTS: The most consistent associations were in males aged 20–59; BMI and WC increased across quartiles of MBzP (adjusted mean BMI = 26.7, 27.2, 28.4, 29.0, p-trend = 0.0002), and positive associations were also found for MEOHP, MEHHP, MEP, and MBP. In females, BMI and WC increased with MEP quartile in adolescent girls (adjusted mean BMI = 22.9, 23.8, 24.1, 24.7, p-trend = 0.03), and a similar but less strong pattern was seen in 20–59 year olds. In contrast, MEHP was inversely related to BMI in adolescent girls (adjusted mean BMI = 25.4, 23.8, 23.4, 22.9, p-trend = 0.02) and females aged 20–59 (adjusted mean BMI = 29.9, 29.9, 27.9, 27.6, p-trend = 0.02). There were no important associations among children, but several inverse associations among 60–80 year olds. CONCLUSION: This exploratory, cross-sectional analysis revealed a number of interesting associations with different phthalate metabolites and obesity outcomes, including notable differences by gender and age subgroups. Effects of endocrine disruptors, such as phthalates, may depend upon endogenous hormone levels, which vary dramatically by age and gender. Individual phthalates also have different biologic and hormonal effects. Although our study has limitations, both of these factors could explain some of the variation in the observed associations. These preliminary data support the need for prospective studies in populations at risk for obesity.National Institutes of Environmental Health Sciences (R21ES013724
Immune response of healthy horses to DNA constructs formulated with a cationic lipid transfection reagent
Background Deoxyribonucleic acid (DNA) vaccines are used for experimental
immunotherapy of equine melanoma. The injection of complexed linear DNA
encoding interleukin (IL)-12/IL-18 induced partial tumour remission in a
clinical study including 27 grey horses. To date, the detailed mechanism of
the anti-tumour effect of this treatment is unknown. Results In the present
study, the clinical and cellular responses of 24 healthy horses were monitored
over 72 h after simultaneous intradermal and intramuscular application of
equine IL-12/IL-18 DNA (complexed with a transfection reagent) or comparative
substances (transfection reagent only, nonsense DNA, nonsense DNA depleted of
CG). Although the strongest effect was observed in horses treated with
expressing DNA, horses in all groups treated with DNA showed systemic
responses. In these horses treated with DNA, rectal temperatures were elevated
after treatment and serum amyloid A increased. Total leukocyte and neutrophil
counts increased, while lymphocyte numbers decreased. The secretion of tumour
necrosis factor alpha (TNFα) and interferon gamma (IFNγ) from peripheral
mononuclear blood cells ex vivo increased after treatments with DNA, while
IL-10 secretion decreased. Horses treated with DNA had significantly higher
myeloid cell numbers and chemokine (C-X-C motif) ligand (CXCL)-10 expression
in skin samples at the intradermal injection sites compared to horses treated
with transfection reagent only, suggesting an inflammatory response to DNA
treatment. In horses treated with expressing DNA, however, local CXCL-10
expression was highest and immunohistochemistry revealed more intradermal
IL-12-positive cells when compared to the other treatment groups. In contrast
to non-grey horses, grey horses showed fewer effects of DNA treatments on
blood lymphocyte counts, TNFα secretion and myeloid cell infiltration in the
dermis. Conclusion Treatment with complexed linear DNA constructs induced an
inflammatory response independent of the coding sequence and of CG motif
content. Expressing IL-12/IL-18 DNA locally induces expression of the
downstream mediator CXCL-10. The grey horses included appeared to display an
attenuated immune response to DNA treatment, although grey horses bearing
melanoma responded to this treatment with moderate tumour remission in a
preceding study. Whether the different immunological reactivity compared to
other horses may contributes to the melanoma susceptibility of grey horses
remains to be elucidated
Recommended from our members
Endocrine disruptors and obesity
The purpose of this review is to summarise current evidence that some environmental chemicals may be able to interfere in endocrine regulation of energy metabolism and adipose tissue structure. Recent findings demonstrate that such endocrine disrupting chemicals, termed “obesogens”, can promote adipogenesis and cause weight gain. This includes compounds to which the human population is exposed in daily life through their use in pesticides/herbicides, industrial and household products, plastics, detergents, flame retardants and ingredients in personal care products. Animal models and epidemiological studies have shown that an especially sensitive time for exposure is in utero or the neonatal period. In summarising the actions of obesogens, it is noteworthy that as their structures are mainly lipophilic, their ability to increase fat deposition has the added consequence of increasing the capacity for their own retention. This has the potential for a vicious spiral not only of increasing obesity but also increasing retention of other lipophilic pollutant chemicals with an even broader range of adverse actions. This might offer an explanation as to why obesity is an underlying risk factor for so many diseases including cancer
Кинетика восстановления железа при восстановительной плавке рудоугольных окатышей
Исследовано влияние интенсивности теплообмена на кинетику восстановления железа в процессе плавки рудоугольных окатышей. Показано, что с ростом интенсивности теплообмена повышается скорость восстановительных процессов. Вследствие роста коэффициента теплообмена увеличивается глубина восстановленного слоя окатыша, существенно изменяются его структура и химический состав образующейся металлической фазы.Досліджено вплив інтенсивності теплообміну на кінетику відновлення заліза в процесі плавки рудовугільних окатишів. Показано, що при зростанні інтенсивності теплообміну підвищується швидкість відновлювальних процесів. Внаслідок зростання коефіцієнту теплообміну збільшується глибина відновленого шару окатиша, суттєво змінюються його структура та хімічний склад металевої фази, що утворюється.Influence of intensity of heat exchange is investigational on kinetics reduction of iron in the process of melting ore-coal pellets. It is rotined that speed of reduction processes rises with growth of intensity of heat exchange. Because of growth of coefficient of heat exchange the depth of the recovered layer of pellet is increased, his structure and chemical composition of appearing metallic phase changes substantially
Hydrogen-Bond Driven Loop-Closure Kinetics in Unfolded Polypeptide Chains
Characterization of the length dependence of end-to-end loop-closure kinetics in unfolded polypeptide chains provides an understanding of early steps in protein folding. Here, loop-closure in poly-glycine-serine peptides is investigated by combining single-molecule fluorescence spectroscopy with molecular dynamics simulation. For chains containing more than 10 peptide bonds loop-closing rate constants on the 20–100 nanosecond time range exhibit a power-law length dependence. However, this scaling breaks down for shorter peptides, which exhibit slower kinetics arising from a perturbation induced by the dye reporter system used in the experimental setup. The loop-closure kinetics in the longer peptides is found to be determined by the formation of intra-peptide hydrogen bonds and transient β-sheet structure, that accelerate the search for contacts among residues distant in sequence relative to the case of a polypeptide chain in which hydrogen bonds cannot form. Hydrogen-bond-driven polypeptide-chain collapse in unfolded peptides under physiological conditions found here is not only consistent with hierarchical models of protein folding, that highlights the importance of secondary structure formation early in the folding process, but is also shown to speed up the search for productive folding events
- …