Relevant distance between two different instances of the same potential energy in protein folding

In the context of complex systems and, particularly, of protein folding, a physically meaningful distance is defined which allows to make useful statistical statements about the way in which energy differences are modified when two different instances of the same potential-energy function are used. When the two instances arise from the fact that different algorithms or different approximations are used, the distance herein defined may be used to evaluate the relative accuracy of the two methods. When the difference is due to a change in the free parameters of which the potential depends on, the distance can be used to quantify, in each region of parameter space, the robustness of the modeling to such a change and this, in turn, may be used to assess the significance of a parameters' fit. Both cases are illustrated with a practical example: the study of the Poisson-based solvation energy in the Trp-Cage protein (PDB code 1L2Y).     

Estrogen Receptor Expression Is Associated with DNA Repair Capacity in Breast Cancer

Estrogen-receptor-positive (ER+) tumors employ complex signaling that engages in crosstalk with multiple pathways through genomic and non-genomic regulation. A greater understanding of these pathways is important for developing improved biomarkers that can better determine treatment choices, risk of recurrence and cancer progression. Deficiencies in DNA repair capacity (DRC) is a hallmark of breast cancer (BC); therefore, in this work we tested whether ER signaling influences DRC. We analyzed the association between ER positivity (% receptor activation) and DRC in 270 BC patients, then further stratified our analysis by HER2 receptor status. Our results show that among HER2 negative, the likelihood of having low DRC values among ER- women is 1.92 (95% CI: 1.03, 3.57) times the likelihood of having low DRC values among ER+ women, even adjusting for different potential confounders (p<0.05); however, a contrary pattern was observed among HER2 positives women. In conclusion, there is an association between DRC levels and ER status, and this association is modified by HER2 receptor status. Adding a DNA repair capacity test to hormone receptor testing may provide new information on defective DNA repair phenotypes, which could better stratify BC patients who have ER+ tumors. ER+/HER2- tumors are heterogeneous, incompletely defined, and clinically challenging to treat; the addition of a DRC test could better characterize and classify these patients as well as help clinicians select optimal therapies, which could improve outcomes and reduce recurrences.     

Physical and chemical characters,phytoplankton and primary production of Ezequiel Ramos Mexía Reservoir (Argentina)

We describe the distribution in space and time of a series of physical and chemical variables, phyto-plankton, and primary production in Ezequiel Ramos Mexía Reservoir (Argentina). Its waters are soft, poor in nutrients and with a low transparency that greatly depresses primary production. Phytoplankton data indicate the presence of 79 taxa with Bacillariophyceae, Cyanophyta and Chlorophyta alternatively dominant. Chlorophyll a was always low and never exceeded 3 mg m⁻³. Based on these results, the trophic status of this ecosystem is discussed.     

Bioenergetics and growth in the ctenophore <Emphasis Type="Italic">Pleurobrachia pileus</Emphasis>

Knowledge of how energetic parameters relate to fluctuating factors in the natural habitat is necessary when evaluating the role of gelatinous zooplankton in the carbon flow of coastal waters. In laboratory experiments, we assessed feeding, respiration and growth of the ctenophore, Pleurobrachia pileus, and constructed carbon budgets. Clearance rates (F, l d⁻¹) of laboratory-reared Acartia tonsa as prey increased as a function of ctenophore polar length (L, mm) as F = 0.17L ^1.9. For ctenophores larger than about 11 mm, clearance rate was depressed in containers of 30–50 l volume. Clearance rates on field-collected prey were highest on the copepod, Centropages typicus, intermediate on the cladoceran, Evadne nordmanni and low on the copepods, Acartia clausi and Temora longicornis. Specific growth rates of 8–10 mm P. pileus increased with increasing prey concentrations to a maximum of 0.09 d⁻¹ attained at prey carbon densities of 40 and 100 μg C l⁻¹ of Artemia salina and A. tonsa, respectively. Weight-specific respiration rates increased hyperbolically with prey concentration. From experiments in which growth, ingestion and respiration were measured simultaneously, a carbon budget was constructed for individuals growing at maximum rates; from the measured parameters, the assimilation efficiency and net growth efficiency were estimated to be 22 and 37%, respectively. We conclude that the predation rates of P. pileus depend on ctenophore size, prey species, prey density and experimental container volume. Because the specific growth rates, respiration, assimilation and net growth efficiencies all were affected by food availability, knowledge of the ambient prey field is critical when evaluating the role of P. pileus in the carbon flow in coastal waters.     

Relación del factor de crecimiento de fibroblastos 21 con indicadores de masa y función muscular en personas mayores con sobrepeso u obesidad. Estudio exploratorio

BackgroundAge-related decreases in muscle mass and function are associated with the development of metabolic impairments, particularly in the context of obesity. Fibroblast growth factor 21 (FGF-21) has been suggested as a common mediator of both processes. No known studies have examined the association between FGF-21 and muscle mass and function in overweight or obese older adults. With this in mind, this study aimed to investigate the association between plasma levels of FGF-21 and muscle mass and function outcomes in overweight or obese older adults.Materials and methodsExploratory study, which included 39 adults of 60-70 years old with body mass indexes > 25 kg/m². As study outcomes, measurements were made of appendicular muscle mass (AMM), grip strength, 5 times sit-to-stand test (5xSTT), as well as plasma levels of FGF-21, fasting glucose, and insulin. The homeostatic model assessment index (HOMA-IR) was also calculated to determine the presence of insulin resistance.ResultsSignificant relationships were found between plasma levels of FGF-21 vs 5xSTT (rho = 0.49; P < .05). Moreover, FGF-21 levels were significantly higher in those with insulin resistance (P < .05), as well as with having lower levels of AMM (P < .05).ConclusionThere is a relationship between the plasma levels of FGF-21 and muscle function outcomes in overweight or obese older adults. Future studies should investigate the potential causalities between these relationships.     

Distinguishing characteristics between pandemic 2009-2010 influenza A (H1N1) and other viruses in patients hospitalized with respiratory illness

Background

Differences in clinical presentation and outcomes among patients infected with pandemic 2009 influenza A H1N1 (pH1N1) compared to other respiratory viruses have not been fully elucidated.

Methodology/Principal Findings

A retrospective study was performed of all hospitalized patients at the peak of the pH1N1 season in whom a single respiratory virus was detected by a molecular assay targeting 18 viruses/subtypes (RVP, Luminex xTAG). Fifty-two percent (615/1192) of patients from October, 2009 to December, 2009 had a single respiratory virus (291 pH1N1; 207 rhinovirus; 45 RSV A/B; 37 parainfluenza; 27 adenovirus; 6 coronavirus; and 2 metapneumovirus). No seasonal influenza A or B was detected. Individuals with pH1N1, compared to other viruses, were more likely to present with fever (92% & 70%), cough (92% & 86%), sore throat (32% & 16%), nausea (31% & 8%), vomiting (39% & 30%), abdominal pain (14% & 7%), and a lower white blood count (8,500/L & 13,600/L, all p-values<0.05). In patients with cough and gastrointestinal complaints, the presence of subjective fever/chills independently raised the likelihood of pH1N1 (OR 10). Fifty-five percent (336/615) of our cohort received antibacterial agents, 63% (385/615) received oseltamivir, and 41% (252/615) received steroids. The mortality rate of our cohort was 1% (7/615) and was higher in individuals with pH1N1 compared to other viruses (2.1% & 0.3%, respectively; p = 0.04).

Conclusions/Significance

During the peak pandemic 2009–2010 influenza season in Rhode Island, nearly half of patients admitted with influenza-like symptoms had respiratory viruses other than influenza A. A high proportion of patients were treated with antibiotics and pH1N1 infection had higher mortality compared to other respiratory viruses.     

Updating fearful memories with extinction training during reconsolidation: a human study using auditory aversive stimuli

Learning to fear danger in the environment is essential to survival, but dysregulation of the fear system is at the core of many anxiety disorders. As a consequence, a great interest has emerged in developing strategies for suppressing fear memories in maladaptive cases. Recent research has focused in the process of reconsolidation where memories become labile after being retrieved. In a behavioral manipulation, Schiller et al., (2010) reported that extinction training, administrated during memory reconsolidation, could erase fear responses. The implications of this study are crucial for the possible treatment of anxiety disorders without the administration of drugs. However, attempts to replicate this effect by other groups have been so far unsuccessful. We sought out to reproduce Schiller et al., (2010) findings in a different fear conditioning paradigm based on auditory aversive stimuli instead of electric shock. Following a within-subject design, participants were conditioned to two different sounds and skin conductance response (SCR) was recorded as a measure of fear. Our results demonstrated that only the conditioned stimulus that was reminded 10 minutes before extinction training did not reinstate a fear response after a reminder trial consisting of the presentation of the unconditioned stimuli. For the first time, we replicated Schiller et al., (2010) behavioral manipulation and extended it to an auditory fear conditioning paradigm.     

Allele-specific expression of a weeping lovegrass gene from the lignin biosynthetic pathway,caffeoyl-coenzyme A 3-<Emphasis Type="Italic">O</Emphasis>-methyltransferase

Eragrostis curvula is an important forage grass in marginal regions for its capacity to grow and develop in sandy, not very fertile soils and for its drought tolerance. However, its widespread use for animal production is limited at present since it has low forage quality. In forage species, lignin content has been recognized as one of the main factors that affects this parameter. The O-methylation at the C3 position of the phenolic ring of caffeic acid constitutes a key step in the lignin biosynthetic pathway. The enzyme caffeoyl-CoA 3-O-methyltransferase (CCoAOMT) catalyzes such methylation and is thus considered an interesting target for molecular breeding programs. Here we report the isolation of the full-length CCoAOMT cDNA from the E. curvula inflorescences library. Primers based on this sequence led to the amplification of seven unigenes from genomic DNA from cvs. Tanganyika, Don Pablo and Kromdraai. Since the major differences were located in the intron regions, these seven sequences resulted in four possible allelic forms. We further evaluated the allelic expression per tissue in cv. Tanganyika, the most variable genotype. The four alleles predicted by the genomic sequences were found to be expressed. Three of them were common to inflorescences, roots and leaves, while the other one seemed to be specific for inflorescences. The statistical analysis showed that the expression was not organ-independent. The information reported here constitutes a valuable tool for E. curvula breeding programs, aiming to alter lignin biosynthesis to improve forage quality without causing undesirable effects.     

Cinnabar-Preserved Bone Structures from Primary Osteogenesis and Fungal Signatures in Ancient Human Remains

The Red Queen remains (700 A.C.) found at Palenque, México, are examples of cinnabar (HgS) application to royal remains during pre-Hispanic times. The Red Queen remains are those of a ca. 30–35-yr-old female and present a striking similarity to the remains of another Mayan woman found at Copan, Honduras. Thus, covering the remains of royal women with HgS may have been a common practice in the Mayan civilization. High resolution microdiffraction and microscopic analysis of the Red Queen remains showed the presence of nanotubular organic minerals comparable in composition and molecular dimensions to collagen fibrils, and in spatial ordering to collagen fiber networks. Fungal structures are rare in the geological record because of poor preservation potential. Micrographs revealed the preservation of fungal signatures, with morphology comparable to parasitic fungal-coral matrix associations, consistent with the idea that fungal remains can be preserved in environments which contain high Hg concentrations. The well-preserved signatures of fungus-animal interactions and primary osteogenesis in the Red Queen remains are attributed to the long-term antibacterial activity of HgS and the association of sulfur components with nanotubular structures.