Evolutionary morphology of the Tenrecoidea (Mammalia) hindlimb skeleton

The tenrecs of Central Africa and Madagascar provide an excellent model for exploring adaptive radiation and functional aspects of mammalian hindlimb form. The pelvic girdle, femur, and crus of 13 tenrecoid species, and four species from the families Solenodontidae, Macroscelididae, and Erinaceidae, were examined and measured. Results from qualitative and quantitative analyses demonstrate remarkable diversity in several aspects of knee and hip joint skeletal form that are supportive of function‐based hypotheses, and consistent with studies on nontenrecoid eutherian postcranial adaptation. Locomotor specialists within Tenrecoidea exhibit suites of characteristics that are widespread among eutherians with similar locomotor behaviors. Furthermore, several characters that are constrained at the subfamily level were identified. Such characters are more indicative of postural behavior than locomotor behavior. J. Morphol., 2009. © 2008 Wiley‐Liss, Inc.     

Acylceramides and lanosterol-lipid markers of terminal differentiation in cultured human keratinocytes: Modulating effect of retinoic acid

Summary Epidermal differentiation is accompanied by profound changes in the synthesis of a variety of intracellular proteins and intercellular lipids. In conventional, submerged culture keratinocytes have been shown to lose the ability to synthesize the protein markers of differentiation. They re-express them, however, when they are cultured in medium supplemented with delipidized [retinoic acid (RA)-depleted] serum or in air-exposed cultures using de-epidermized dermis (DED) as a substrate. Recent studies have revealed that acylceramides (AC) and lanosterol (LAN), which are present only in trace amounts in cultures of keratinocytes grown under submerged conditions on DED in medium supplemented with normal serum, become expressed in significant amounts when the culture is lifted to the air-liquid interface. Inasmuch as culture conditions may markedly affect the extent of keratinocyte differentiation, the present study aimed to investigate the effect of normal (RA-containing) or delipidized (RA-depleted) serum and of RA administration on lipid composition (especially of the AC and LAN contents) in cells cultured under submerged and air-exposed conditions. To test a possible effect of dermal substrate (used in the air-exposed model), the lipid composition of keratinocytes grown under submerged conditions on a plastic and on a dermal substrate (de-epidermized dermis, DED) has also been compared. The results revealed that under all culture conditions, RA deprivation of fetal bovine serum resulted in a marked increase of total ceramide content. Even under submerged conditions, the presence of both AC and LAN could be detected. In air-exposed culture, the content of these lipids was markedly increased. Addition of RA at 1 μM concentration to cultures grown in RA-depleted medium induced marked changes in lipid composition under all culture conditions tested. In cells grown under submerged conditions (both on plastic and on DED) AC and LAN were no longer present in detectable amounts. Also in air-exposed culture, a marked decrease in the content of these lipids was observed. These results suggest that liposoluble serum components, like RA, control the synthesis of lipids that are present in later stages of epidermal differentiation.     

All the eggs in one basket: Are island refuges securing an endangered passerine?

Refuges for threatened species are important to prevent species extinction. They provide protection from a range of environmental and biotic stressors, and ideally provide protection against all threatening processes. However, for some species it may not be clear why some areas are refuges and others are not. The forty‐spotted pardalote (Pardalotus quadragintus) is an endangered, sedentary, cryptic and specialised bird endemic to the island of Tasmania, Australia. Having undergone an extreme range contraction over the past century the species is now mostly confined to a few small offshore island refuges. Key threatening processes to the species include habitat loss, wildfire, competition and predation. The ways in which these processes have molded the species’ contemporary range have not been clearly evaluated. Furthermore, the security of the remnant population within refuges is uncertain. To overcome this uncertainty we assessed key threats and established the population status in known refuges by developing a robust survey protocol within an occupancy modelling framework. We discuss our results in the context of planning trial reintroductions of this endangered species in suitable habitat across its former range. We found very high occupancy rates (0.75–0.96) at two refuges and in suitable conditions, the species was highly detectable (p, 0.43–0.77). At a third location our surveys indicated a local extinction, likely due to recent wildfire. We demonstrate that all refuges are at high risk of one or more threatening processes and the current distribution across island refuges is unlikely to secure the species from extinction. We identified large areas of potential habitat across the species’ former mainland range, but these are likely too distant from source populations for natural recolonisation. We propose that establishing new populations of forty‐spotted pardalotes via reintroduction is essential to secure the species and that this is best achieved while robust source populations still exist.     

Water stress resilient cereal crops: Lessons from wild relatives

Cereal crops are significant contributors to global diets. As climate change disrupts weather patterns and wreaks havoc on crops, the need for generating stress-resilient, high-yielding varieties is more urgent than ever. One extremely promising avenue in this regard is to exploit the tremendous genetic diversity expressed by the wild ancestors of current day crop species. These crop wild relatives thrive in a range of environments and accordingly often harbor an array of traits that allow them to do so. The identification and introgression of these traits into our staple cereal crops can lessen yield losses in stressful environments. In the last decades, a surge in extreme drought and flooding events have severely impacted cereal crop production. Climate models predict a persistence of this trend, thus reinforcing the need for research on water stress resilience. Here we review: (i) how water stress (drought and flooding) impacts crop performance; and (ii) how identification of tolerance traits and mechanisms from wild relatives of the main cereal crops, that is, rice, maize, wheat, and barley, can lead to improved survival and sustained yields in these crops under water stress conditions.     

The relationship between relative weight and school attendance among elementary schoolchildren

Objective: To determine the relationship between relative weight and school attendance among elementary schoolchildren. Research Methods and Procedures: A total of 1069 fourth to sixth graders from nine elementary schools in the inner city of Philadelphia, PA, were part of an ongoing randomized control trial to assess prevention strategies for obesity. The mean rate of students eligible for free/reduced meals was 82.9 ± 11.5%. Weight was measured in the second semester of the academic year. Absentee data for the entire academic year were recorded by homeroom teachers. Participants were classified into relative weight categories described by the Institute of Medicine: underweight, normal‐weight, overweight, and obese. Results: ANOVA showed that overweight children were absent significantly more than normal‐weight children (12.2 ± 11.7 days vs.10.1 ± 10.5 days) (p < 0.05). Linear regression showed that the obese category remained a significant contributor to the number of days absent even after adjusting for age, race/ethnicity, and gender. Discussion: These data suggest that in addition to the medical and psychosocial consequences of being overweight, heavier children have greater risk for school absenteeism than their normal‐weight peers. As the rate of childhood obesity increases, parallel increases in school absenteeism should be expected.     

4-hydroxynonenal in foodstuffs: heme concentration, fatty acid composition and freeze-drying are determining factors

4-Hydroxynonenal (HNE) is a product of lipid peroxidation. It has been often used as a biomarker of endogenous lipid peroxidation and its concentration is increased in several diseases. But HNE is not only formed during lipid peroxidation occurring in the body. Some authors have shown that it is also present in oxidized oils and in meats. The aim of this study is to compare the effect of food composition (heme iron, fatty acid composition) or freeze-drying on HNE formation in foodstuffs. The methodology is based on extraction/purification procedure followed by HPLC separation with UV detection. As HNE is chemically very reactive and binds easily to proteins, we used radiolabeled HNE to calculate extraction efficiency, so total HNE can be estimated as only free HNE can be measured. The concomitant presence of both heme iron and omega 6 fatty acids, such as linoleic acid, is important for HNE formation in foodstuffs. Freeze-drying increases this formation.     

Yif1B Is Involved in the Anterograde Traffic Pathway and the Golgi Architecture

Yif1B is an intracellular membrane‐bound protein belonging to the Yip family, shown previously to control serotonin 5‐HT_1A receptor targeting to dendrites. Because some Yip proteins are involved in the intracellular traffic between the ER and the Golgi, here we investigated the precise localization of Yif1B in HeLa cells. We found that Yif1B is not resident into the Golgi, but rather belongs to the IC compartment. After analyzing the role of Yif1B in protein transport, we showed that the traffic of the VSVG protein marker was accelerated in Yif1B depleted HeLa cells, as well as in hippocampal neurons from Yif1B KO mice. Conversely, Yif1B depletion in HeLa cells did not change the retrograde traffic of ShTx. Interestingly, in long term depletion of Yif1B as in Yif1B KO mice, we observed a disorganized Golgi architecture in CA1 pyramidal hippocampal neurons, which was confirmed by electron microscopy. However, because short term depletion of Yif1B did not change Golgi structure, it is likely that the implication of Yif1B in anterograde traffic does not rely on its role in structural organization of the Golgi apparatus, but rather on its shuttling between the ER, the IC and the Golgi compartments.      

Long‐term impacts of manure amendments on carbon and greenhouse gas dynamics of rangelands

Livestock manure is applied to rangelands as an organic fertilizer to stimulate forage production, but the long‐term impacts of this practice on soil carbon (C) and greenhouse gas (GHG) dynamics are poorly known. We collected soil samples from manured and nonmanured fields on commercial dairies and found that manure amendments increased soil C stocks by 19.0 ± 7.3 Mg C ha^?1 and N stocks by 1.94 ± 0.63 Mg N ha^?1 compared to nonmanured fields (0–20 cm depth). Long‐term historical (1700–present) and future (present–2100) impacts of management on soil C and N dynamics, net primary productivity (NPP), and GHG emissions were modeled with DayCent. Modeled total soil C and N stocks increased with the onset of dairying. Nitrous oxide (N₂O) emissions also increased by ~2 kg N₂O‐N ha^?1 yr^?1. These emissions were proportional to total N additions and offset 75–100% of soil C sequestration. All fields were small net methane (CH₄) sinks, averaging ?4.7 ± 1.2 kg CH₄‐C ha^?1 yr^?1. Overall, manured fields were net GHG sinks between 1954 and 2011 (?0.74 ± 0.73 Mg CO₂ e ha^?1 yr^?1, CO₂e are carbon dioxide equivalents), whereas nonmanured fields varied around zero. Future soil C pools stabilized 40–60 years faster in manured fields than nonmanured fields, at which point manured fields were significantly larger sources than nonmanured fields (1.45 ± 0.52 Mg CO₂e ha^?1 yr^?1 and 0.51 ± 0.60 Mg CO₂e ha^?1 yr^?1, respectively). Modeling also revealed a large background loss of soil C from the passive soil pool associated with the shift from perennial to annual grasses, equivalent to 29.4 ± 1.47 Tg CO₂e in California between 1820 and 2011. Manure applications increased NPP and soil C storage, but plant community changes and GHG emissions decreased, and eventually eliminated, the net climate benefit of this practice.