Marine macrophysiology: studying physiological variation across large spatial scales in marine systems

A new approach toward understanding marine ecosystems has emerged through the integration of ecological physiology and macroecology. This multidisciplinary approach, titled here marine macrophysiology, facilitates unique insight into the foundation of macro-scale ecological patterns, such as biogeographic distributions, via examination of functional attributes of marine organisms across large spatial scales. For example, these broad-scale physiological inquiries confer the ability to directly assess the abundant-center hypothesis (aka Brown's principle) which proposes that species have decreased performance toward their range edges. By extension, the marine macrophysiological perspective also stands to clarify our understanding of more complex macro-scale phenomena such as biological invasions, the design of marine protected areas, and species' responses to global climate change. In this article, we review recent marine macrophysiology research and offer insights into future directions for this emerging field.     

Male anti-predation services in primates as costly signalling? A comparative analysis and review

In species in which adults of the two sexes show long-term association, males often engage in acts of assistance (“services”) aimed at females and/or their young in various behavioural contexts that are not reciprocated. We conducted a quantitative review of the primate literature on sex differences in involvement in protection against predation. We found that males were more likely to be at the front of group progressions, especially in contexts of increased risk, were more vigilant, sometimes to the point of becoming sentinels, were more active in mobbing, and were far more likely to counter-attack felids and monkey-eating raptors than females did. Our evaluation showed that these services may be an expression of male parental care or aimed at bonded partners, but we also encountered many cases in which non-sires, unrelated to either females or immatures, provide them. We hence investigate explanations invoking group augmentation or costly signalling. Currently, available data on male anti-predation services in nonhuman primates do not allow us to distinguish among them, although costly signalling better explains data on birds and humans. We develop predictions that will allow more detailed tests of the various hypotheses for this understudied phenomenon.     

Has the Child Welfare Profession Discovered Nepotistic Biases?

A major trend in foster care in developed countries over the past quarter century has been a shift toward placing children with “kin” rather than with unrelated foster parents. This change in practice is widely backed by legislation and is routinely justified as being in the best interests of the child. It is tempting to interpret this change as indicating that the child welfare profession has belatedly discovered that human social sentiments are nepotistic in their design, such that kin tend to be the most nurturant alloparents. Arguably, however, the change in practice has been driven by demographic, economic, and political forces rather than by discovery of its benefits. More and better research is needed before we can be sure that children have actually benefitted.     

Constitutive expression of cathepsin K in the human intervertebral disc: new insight into disc extracellular matrix remodeling via cathepsin K and receptor activator of nuclear factor-κB ligand

Introduction  

Cathepsin K is a recently discovered cysteine protease which cleaves the triple helical domains of type I to II collagen. It has been shown to be up-regulated in synovial tissue from osteoarthritic and rheumatoid patients, and is a component in normal and nonarthritic cartilage, where it increases with aging. Studies on heart valve development have recently shown that receptor activator of nuclear factor-κB ligand (RANKL) acts during valve remodeling to promote cathepsin K expression. Since extracellular matrix remodeling is a critical component of disc structure and biomechanical function, we hypothesized that cathepsin K and RANKL may be present in the human intervertebral disc.     

Exertional rhabdomyolysis in an adolescent athlete during preseason conditioning: a perfect storm

Cleary, MA, Sadowski, KA, Lee, SY-C, Miller, GL, and Nichols, AW. Exertional rhabdomyolysis in an adolescent athlete during preseason conditioning: a perfect storm. J Strength Cond Res 25(12): 3506-3513, 2011-The purpose of this brief review is to present a case of a healthy, male adolescent athlete (age = 16 years, body mass = 67.9 kg, height = 165.5 cm) who participated in a 3-day preseason wrestling camp which resulted in hospitalization for exertional rhabdomyolysis. As part of the preseason conditioning program directed by the coaches, the athlete completed 60 minutes of short, intense intervals of wall-sits, squats, sit-ups, push-ups, lunges, and plyometric jumps. The following day, the athlete continued his vigorous training consisting of running drills. That night he noticed voiding dark brown urine the color of cola. The day after the camp ended, the athlete reported to his Athletic Trainers with the chief complaint of severe bilateral leg pain in his quadriceps. Two days after the initial assessment, he was admitted to the hospital where he was diagnosed with exertional rhabdomyolysis based on creatine kinase (CK) levels that peaked at 146,000 IU·L, elevated far beyond normal (normal range = 58-280 IU·L). The athlete was hospitalized for 6 days where he received intravenous normal saline for rehydration, and his CK levels were assessed daily. Athletic Trainers, personal trainers, physical education teachers, and coaches should be aware that exertional rhabdomyolysis is the most common form of rhabdomyolysis and affects individuals who participate in novel and intense exercise to which they are unaccustomed. Stressful ambient conditions may lead to dehydration and exacerbation of the condition, particularly when the individual is not accustomed to the exercise intensity.     

Primary human mDC1, mDC2, and pDC dendritic cells are differentially infected and activated by respiratory syncytial virus

Respiratory syncytial virus (RSV) causes recurrent infections throughout life. Vaccine development may depend upon understanding the molecular basis for induction of ineffective immunity. Because dendritic cells (DCs) are critically involved in early responses to infection, their interaction with RSV may determine the immunological outcome of RSV infection. Therefore, we investigated the ability of RSV to infect and activate primary mDCs and pDCs using recombinant RSV expressing green fluorescent protein (GFP). At a multiplicity of infection of 5, initial studies demonstrated ～6.8% of mDC1 and ～0.9% pDCs were infected. We extended these studies to include CD1c(-)CD141(+) mDC2, finding mDC2 infected at similar frequencies as mDC1. Both infected and uninfected cells upregulated phenotypic markers of maturation. Divalent cations were required for infection and maturation, but maturation did not require viral replication. There is evidence that attachment and entry/replication processes exert distinct effects on DC activation. Cell-specific patterns of RSV-induced maturation and cytokine production were detected in mDC1, mDC2, and pDC. We also demonstrate for the first time that RSV induces significant TIMP-2 production in all DC subsets. Defining the influence of RSV on the function of selected DC subsets may improve the likelihood of achieving protective vaccine-induced immunity.     

Entry of Yersinia pestis into the viable but nonculturable state in a low-temperature tap water microcosm

Yersinia pestis, the causative agent of plague, has caused several pandemics throughout history and remains endemic in the rodent populations of the western United States. More recently, Y. pestis is one of several bacterial pathogens considered to be a potential agent of bioterrorism. Thus, elucidating potential mechanisms of survival and persistence in the environment would be important in the event of an intentional release of the organism. One such mechanism is entry into the viable but non-culturable (VBNC) state, as has been demonstrated for several other bacterial pathogens. In this study, we showed that Y. pestis became nonculturable by normal laboratory methods after 21 days in a low-temperature tap water microcosm. We further show evidence that, after the loss of culturability, the cells remained viable by using a variety of criteria, including cellular membrane integrity, uptake and incorporation of radiolabeled amino acids, and protection of genomic DNA from DNase I digestion. Additionally, we identified morphological and ultrastructural characteristics of Y. pestis VBNC cells, such as cell rounding and large periplasmic spaces, by electron microscopy, which are consistent with entry into the VBNC state in other bacteria. Finally, we demonstrated resuscitation of a small number of the non-culturable cells. This study provides compelling evidence that Y. pestis persists in a low-temperature tap water microcosm in a viable state yet is unable to be cultured under normal laboratory conditions, which may prove useful in risk assessment and remediation efforts, particularly in the event of an intentional release of this organism.