Preclinical Models for Studying NASH-Driven HCC: How Useful Are They?

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Photosynthetic Carbon Incorporation and Turnover in Antarctic Cryptoendolithic Microbial Communities: Are They the Slowest-Growing Communities on Earth?

The main forms of terrestrial life in the cold, desolate Ross Desert of Antarctica are lichen-dominated or cyanobacterium-dominated cryptoendolithic (hidden in rock) microbial communities. Though microbial community biomass (as measured by extractable lipid phosphate) was well within the range of values determined for other microbial communities, community lipid carbon turnover times (calculated from community lipid biomass, rates of community photosynthetic carbon incorporation into lipids versus temperature, and the in situ temperature record) were among the longest on Earth (ca. 20,000 years). When the temperature is above freezing and moisture is present, moderate rates of photosynthesis can be measured. Lichen communities had a psychrophilic temperature response (maximal rate of 4.5 ng of C h^-1 m^-2 at 10°C) while cyanobacteria communities had maximal rates at 20 to 30°C (3 ng of C h^-1 m^-2). These extraordinarily slowly growing communities were not nutrient limited. No significant changes in photosynthetic metabolism were observed upon additions of 100 nM to 1 mM nitrate, ammonium, phosphate, and manganese. These simple, tenacious microbial communities demonstrate strategies of survival under conditions normally considered too extreme for life.     

Biogeography and Limno-terrestrial Tardigrades: Are They Truly Incompatible Binomials?

Due to the passive dispersal, tardigrades have been traditionally considered unsuitable for biogeographical studies. However, this paper provides some biogeographical and biological data supporting the possibility of using those animals to solve biogeographical problems at continental level.     

Red Fluorescing Phototrophic Picoplankton in the Laurentian Great Lakes: What Are They and What Are They Doing?

Epifluorescence microscopy, flow cytometry, and transmission electron microscopy were used to characterize the community of red fluorescing (emission >665 nm when excited with blue light) phototrophic picoplankton (RFPP) in lakes Huron and Michigan. A population of coccoid to ovate eukaryotic cells with a mean size of 1.2 μm dominated the RFPP community in both surface and deep water samples. Abundant prochlorophyte populations were not found in any samples. Comparisons of counts with epifluorescence microscopy and flow cytometry, revealed that RFPP were adequately enumerated with standard epifluorescence microscopy. These RFPP were significant contributors to total phototrophic picoplankton abundance in both lakes Michigan (24%) and Huron (18%), with maximum seasonal abundance during the May-June period (surface mixing layer temperatures, 3-9 °C). During thermal stratification, maximum vertical abundance was found in the metalimnion/hypolimnion at the 1-5% isolumes. RFPP were only minor contributors (1-7%) to total primary production. Growth rates of RFPP measured with dilution and small inocula growth experiments ranged from 0.05-1.0 d⁻¹. Microzooplankton grazing rates on RFPP measured with dilution experiments were similar to estimated growth rates, accounting for 52-280% of growth on any given date.     

Soil Microbial Communities and Ecological Risk Assessment: Risk Assessors’ Perspective

In the past, ecological risk assessments (ERAs) have generally overlooked the soil microbial community when evaluating the impacts of contaminants in soil. However, the soil microbial community, which includes bacteria and fungi, performs functions necessary for overall ecosystem health, including nitrogen fixation, nutrient cycling, and even degradation of contaminants. The incorporation of the soil microbial community into ERA requires the compilation of adequate toxicity data to complete the hazard assessment phase of the risk assessment. A variety of soil microbial toxicity tests exist that provide rapid and inexpensive results. Surveys of the microbial community at a contaminated site may also provide insight as to their functioning in the presence of contaminants. This paper explores the use of toxicity tests and surveys to evaluate chemical toxicity to microbes. However, many questions related to the best methodological approach to an ERA of the soil microbial community have yet to be answered.     

The Spratlys: Are They Rocks or Islands?

The South China Sea is a multilateral battlefield of conflicting claims to sovereignty over island features and vast areas of maritime jurisdiction. In the middle of the South China Sea lies the Spratly archipelago - some 150 small island features to which six states have made claims. The core of the SCS dispute is access to natural resources, and the rivalling claims to sovereignty over islands are largely based on the assumption that whoever has sovereignty to the features can also claim large areas of ocean space attached to them. The United Nations Convention on the Law of the Sea has codified the regimes of the continental shelf and the exclusive economic zone, and it is accepted that islands, as well as continental territory, generate such zones of maritime jurisdiction. However, one category of islands cannot generate these extensive maritime zones. Article 121(3) of the convention states that "rocks which cannot sustain human habitation or economic life of their own shall have no exclusive economic zone or continental shelf." This provision, if applied to certain features, has the potential to significantly change the scope of the conflict in the Spratlys.     

Are Radical and Conservative Substitution Rates Useful Statistics in Molecular Evolution?

A DNA mutation in a protein coding gene which causes an amino acid change can be classified as conservative or radical depending on the magnitude of the physicochemical difference between the two amino acids: radical mutations involve larger changes than conservative mutations. Here, I examine two key issues in determining whether radical and conservative substitution rates are useful statistics in molecular evolution. The first issue is whether such rates can be estimated reliably, and for this purpose I demonstrate considerable improvements achieved by simple modifications to an existing method. The second issue is whether conservative and radical substitution rates can tell us something about selection on protein function. I address this problem by estimating positive and negative selection on conservative and radical mutations using polymorphism and divergence data from Drosophila. These analyses show that negative selection, but not positive selection, differs significantly between conservative and radical mutations. The power of conservative and radical substitution rates in testing the nearly neutral theory of molecular evolution is illustrated by the analysis of two mammalian datasets.     

Alpha-, Delta- and PP-cells: Are They the Architectural Cornerstones of Islet Structure and Co-ordination?

Islet non-β-cells, the α- δ- and pancreatic polypeptide cells (PP-cells), are important components of islet architecture and intercellular communication. In α-cells, glucagon is found in electron-dense granules; granule exocytosis is calcium-dependent via P/Q-type Ca²⁺-channels, which may be clustered at designated cell membrane sites. Somatostatin-containing δ-cells are neuron-like, creating a network for intra-islet communication. Somatostatin 1-28 and 1-14 have a short bioactive half-life, suggesting inhibitory action via paracrine signaling. PP-cells are the most infrequent islet cell type. The embryologically separate ventral pancreas anlage contains PP-rich islets that are morphologically diffuse and α-cell deficient. Tissue samples taken from the head region are unlikely to be representative of the whole pancreas. PP has anorexic effects on gastro-intestinal function and alters insulin and glucagon secretion. Islet architecture is disrupted in rodent diabetic models, diabetic primates and human Type 1 and Type 2 diabetes, with an increased α-cell population and relocation of non-β-cells to central areas of the islet. In diabetes, the transdifferentiation of non-β-cells, with changes in hormone content, suggests plasticity of islet cells but cellular function may be compromised. Understanding how diabetes-related disordered islet structure influences intra-islet cellular communication could clarify how non-β-cells contribute to the control of islet function.     

Where Are Zoos Going—or Are They Gone?

ABSTRACT

To some, zoos are prisons exploiting animals. In reality zoos range from bad to better. I make this distinction: A bad zoo makes animals work for it; a good zoo works for animals. Good zoos do effective conservation work and continually strive to improve exhibits, relevance to conservation, and inspiring public engagement for wildlife. Many zoos have improved enormously; the better ones being crucial in saving species that would have otherwise gone extinct. Nonetheless, for some people the mere word “zoo” carries impressions of old zoos, bad zoos, circuses, and theme-park shows that many find distasteful. Good zoos know they must innovate forward. As society grows increasingly estranged from nature and continues driving broad declines of wildlife, wild lands, and natural systems, the goal of zoos and every organization concerned with animal welfare should not be to separate humans from other animals, but to entangle all humans in nonhuman lives. Zoos of the next decades must become the first stage in bringing young people into life-long, engaged caring about animals. They could carry on that mission in their communities, in schools, in wild lands, as well as inside their gates. Without a strong public constituency, wild animals will not withstand continued human proliferation. Zoos and aquariums must innovate toward being a crucial force abetting the continued existence of wildness on Earth. Zoos of the future must become uplifting places of respect, rescue, enhancement, conservation, and public engagement.     

The Feet of Overweight and Obese Young Children: Are They Flat or Fat?

Objective: The purpose of this study was to determine whether the flat feet displayed by young obese and overweight children are attributable to the presence of a thicker midfoot plantar fat pad or a lowering of the longitudinal arch relative to that in non‐overweight children. Research Methods and Procedures: Foot anthropometry, an arch index derived from plantar footprints, and midfoot plantar fat pad thickness measured by ultrasound were obtained for 19 overweight/obese preschool children (mean age, 4.3 ± 0.9 years; mean height, 1.07 ± 0.1 m; mean BMI, 18.6 ± 1.2 kg/m²) and 19 non‐overweight children matched for age, height, and sex (mean age, 4.3 ± 0.7 years; mean height, 1.05 ± 0.1 m; mean BMI, 15.7 ± 0.7 kg/m²). Results: Independent t tests revealed no significant between‐subject group differences (p = 0.39) in the thickness of the midfoot plantar fat pad. However, the overweight/obese children had a significantly lower plantar arch height (0.9 ± 0.3 cm) than their non‐overweight counterparts (1.1 ± 0.2 cm; p = 0.04). Discussion: The lower plantar arch height found in the overweight/obese children suggests that the flatter feet characteristic of overweight/obese preschool children may be caused by structural changes in their foot anatomy. It is postulated that these structural changes, which may adversely affect the functional capacity of the medial longitudinal arch, might be exacerbated if excess weight bearing continues throughout childhood and into adulthood.     

Microbial metal-ion reduction and Mars: extraterrestrial expectations?

Dissimilatory metal-ion-reducing bacteria (DMRB) can couple the reduction of a variety of different metal ions to cellular respiration and growth. The excitement of this metabolic group lies not only in the elucidation of a new type of metabolism, but also in the potential use of these abilities for the removal of toxic organics, and in their ability to reduce (and thus, detoxify) other toxic metals, such as U(VI) and Cr(VI). This review focuses on recent advances in the study of DMRB, including the use of external electron shuttles to enhance rates of metal reduction; genome sequencing and consequent genomic and proteomic analyses; new imaging approaches for high resolution analysis of both cells and chemical components; the demonstration of fractionation of stable isotopes of iron during iron reduction; and the elucidation of the types and patterns of secondary mineral formation during metal reduction. One of the secondary minerals is magnetite, the subject of intense controversy regarding the possibility of evidence for life from the Martian meteorite ALH84001. This review thus ends with a short consideration of the evidence for magnetic 'proof' of the existence of past life on Mars.     

Differential Nutrient Limitation of Soil Microbial Biomass and Metabolic Quotients (qCO2): Is There a Biological Stoichiometry of Soil Microbes?

Background

Variation in microbial metabolism poses one of the greatest current uncertainties in models of global carbon cycling, and is particularly poorly understood in soils. Biological Stoichiometry theory describes biochemical mechanisms linking metabolic rates with variation in the elemental composition of cells and organisms, and has been widely observed in animals, plants, and plankton. However, this theory has not been widely tested in microbes, which are considered to have fixed ratios of major elements in soils.

Methodology/Principal Findings

To determine whether Biological Stoichiometry underlies patterns of soil microbial metabolism, we compiled published data on microbial biomass carbon (C), nitrogen (N), and phosphorus (P) pools in soils spanning the global range of climate, vegetation, and land use types. We compared element ratios in microbial biomass pools to the metabolic quotient qCO₂ (respiration per unit biomass), where soil C mineralization was simultaneously measured in controlled incubations. Although microbial C, N, and P stoichiometry appeared to follow somewhat constrained allometric relationships at the global scale, we found significant variation in the C∶N∶P ratios of soil microbes across land use and habitat types, and size-dependent scaling of microbial C∶N and C∶P (but not N∶P) ratios. Microbial stoichiometry and metabolic quotients were also weakly correlated as suggested by Biological Stoichiometry theory. Importantly, we found that while soil microbial biomass appeared constrained by soil N availability, microbial metabolic rates (qCO₂) were most strongly associated with inorganic P availability.

Conclusions/Significance

Our findings appear consistent with the model of cellular metabolism described by Biological Stoichiometry theory, where biomass is limited by N needed to build proteins, but rates of protein synthesis are limited by the high P demands of ribosomes. Incorporation of these physiological processes may improve models of carbon cycling and understanding of the effects of nutrient availability on soil C turnover across terrestrial and wetland habitats.     

Levels of Intervention: How Are They Used in Quebec Hospitals?

In order to promote better practices and communication around end-of-life decision-making, several Canadian hospitals in the province of Quebec have developed a tool called “Levels of Intervention” (LOI). No work to date has been published demonstrating improvement since these forms were implemented. The purpose of the present study was to obtain information about the use of LOI forms across Quebec hospitals and to identify gaps in practice as well as areas for improvement. A retrospective study was undertaken of 299 charts of patients who had died in three Quebec hospitals with a LOI ordered. Results were analysed through a principlism ethical framework. High compliance with the level of intervention ordered at the time of death was recorded, as well as high involvement of patient and/or family, demonstrating the efficiency of LOI in promoting respect for autonomy. Other results show delays in end-of-life care discussions in the course of the hospitalization. Only a small proportion of patients who died had a palliative care consultation, which may reflect equity issues in access to care. This study highlights the importance of the LOI in Quebec and the role it is playing in respect for end-of-life preferences as well as in the involvement of patients and families in the decision-making process. Training specific to end-of-life decision-making conversations would help support the LOI form’s use, as would developing provincial or national guidelines on the use of LOI to standardize organizational policies and practice around end-of-life care.     

Psychosocial Care Needs of Melanoma Survivors: Are They Being Met?

Patients who have survived malignant melanoma for more than five years may lack the opportunity to talk about their burden. As a consequence their psychosocial care needs remain undetected and available supportive interventions may not be utilised. Therefore, the psychosocial burden of this patient group needs to be assessed using specific screening instruments. The aim of this study was to investigate the psychosocial burden of long-term melanoma survivors, their psychosocial care needs and the determinants of these needs. We wanted to find out if the use of professional support corresponds to the care needs defined by experts. Using the cancer registry of Rhineland-Palatinate, melanoma patients diagnosed at least 5 years before the survey were contacted by physicians. N = 689 former patients completed the Hornheide Questionnaire (short form HQ-S) to identify psychosocial support need (scale cut off ≥ 16 or item-based cut-off score) and the potential psychosocial determinants of these needs. Additionally, they were asked about their utilisation of the professional support system. More than one third (36%) of them was in need for professional psychosocial support. The highest burden scores concerned worry about tumour progression. Younger age (< 50), higher general fatigue, higher symptom burden, lower general health, negative social interactions and unfulfilled information needs were significant predictors of the need for psychosocial intervention. Related to the percentage of survivors identified as ‘in need’, the professional support system was underused. Further studies should investigate whether using the HQ-S to routinely identify burdened melanoma patients could lead to better fulfilment of their intervention needs, ultimately enhancing health-related quality of life.     

Intrinsically Disordered Regions in Serum Albumin: What Are They For?

Serum albumin is a major plasma protein in mammalian blood. The importance of this protein lies in its roles in both bioregulation and transport phenomena. Serum albumin binds various metal ions and participates in the transport and storage of fatty acids, bilirubin, steroids amino acids, and many other ligands, usually with regions of hydrophobic surface. Although the primary role of serum albumin is to transport various ligand, its versatile binding capacities and high concentration mean that it can assume a number of additional functions. The major goal of this article is to show how intrinsic disorder is encoded in the amino acid sequence of serum albumin, and how intrinsic disorder is related to functions of this important serum protein.     

Mothers' Perceptions of Their Adolescents' Weight Status: Are They Accurate?

Objective: To evaluate the accuracy of mothers’ perceptions of adolescents’ weight status. Research Methods and Procedures: Parent interviews and adolescent surveys (755) were conducted in an ethnically diverse sample from Project EAT (Eating among Teens). Results: Adolescent weight status was accurately assessed by 60% of mothers, underestimated by 35% of mothers, and overestimated by 5% of mothers. In multivariate analyses, mothers of female adolescents were about half as likely to underestimate their adolescent's weight status as mothers of male adolescents. Nonoverweight mothers were about half as likely as overweight mothers to underestimate their adolescent's weight status. Discussion: Most mothers are able to accurately assess their adolescent's weight status; however, adolescent gender and mothers’ weight status are related to accuracy. Mothers were more likely to underestimate their sons’ weights than their daughters’ weights, and overweight mothers were more likely to be inaccurate in their assessments than nonoverweight mothers. Findings suggest that the majority of parents do not need to be told that their children are overweight; instead, messages to parents of overweight teens should focus on how to provide support for healthy weight management.