Continuity and/or Discontinuity in the Pleistocene peopling of Europe?

Today, a number of European fossils are known which can be dated between 500,000 and 900,000 years ago. These remains provide evidence of an early human settlement of Europe, which apparently predates the emergence of Neanderthals. However, the taxonomic attribution of these fossils and their phylogenetic relationship to each other and to Neanderthals remains unclear. Evidence for a direct phylogenetic relationship with Neanderthals or a discontinuity is not yet conclusive. The task is complicated by the fact that the emergence of the Neanderthal population was not abrupt, but progressive. It is probable that the peopling of Europe during the entire Pleistocene was unique and presented from its very origins an “endemic” (a cul-de-sac) character, which may explain that the first traces of fossils in Europe illustrate particularities in comparison those from Africa and from Asia. Further paleontological discoveries will be needed to redefine the status of these features and to improve our understanding of human evolution in Europe.     

Spring movements of Rüppell's Vulture Gyps rueppellii across the Strait of Gibraltar

Most of our understanding of territorial behaviour in birds comes from studies of temperate species. Territoriality and factors influencing territory size of tropical birds are still poorly studied. In this study, 11 territories of the Cinnamon-breasted Rock Bunting Emberiza tahapisi were measured in the Amurum Forest Reserve and adjoining farmlands. Factors influencing the habitat choice of this species were also studied. Territory sizes ranged from 0.1–0.3 ha with a mean territory size of 0.19 ± 0.1ha. Territory size decreased with increasing food abundance and increased with tree height and number of saplings. The birds did not show signs of territoriality in farmlands but flocked in small groups (mean group size 6.88 ± 0.89). Flock size also increased with increasing number of seeds. In the forested land, birds showed a preference for rocky outcrops, whereas in farmlands, they appeared to prefer open and newly cultivated farmlands with little or no ground cover. Understanding the influence of habitat variables on territory size and habitat selection in a locally abundant and widely distributed tropical species such as the Cinnamon-breasted Rock Bunting thus offers unique opportunities for understanding how changes in landscape caused by land-use regimes may affect populations.     

The Scent of Blood: A Driver of Human Behavior?

The scent of blood is potentially one of the most fundamental and survival-relevant olfactory cues in humans. This experiment tests the first human parameters of perceptual threshold and emotional ratings in men and women of an artificially simulated smell of fresh blood in contact with the skin. We hypothesize that this scent of blood, with its association with injury, danger, death, and nutrition will be a critical cue activating fundamental motivational systems relating to either predatory approach behavior or prey-like withdrawal behavior, or both. The results show that perceptual thresholds are unimodally distributed for both sexes, with women being more sensitive. Furthermore, both women and men’s emotional responses to simulated blood scent divide strongly into positive and negative valence ratings, with negative ratings in women having a strong arousal component. For women, this split is related to the phase of their menstrual cycle and oral contraception (OC). Future research will investigate whether this split in both genders is context-dependent or trait-like.     

Discontinuity of Human Presence at Atapuerca during the Early Middle Pleistocene: A Matter of Ecological Competition?

Increasing evidence suggests that the European human settlement is older than 1.2 Ma. However, there is a fierce debate about the continuity or discontinuity of the early human settlement of Europe. In particular, evidence of human presence in the interval 0.7−0.5 Ma is scarce in comparison with evidence for the previous and later periods. Here, we present a case study in which the environmental conditions at Sierra de Atapuerca in the early Middle Pleistocene, a period without evidence of human presence, are compared with the conditions in the previous period, for which a relatively intense human occupation is documented. With this objective in mind, the available resources for a human population and the intensity of competition between secondary consumers during the two periods are compared using a mathematical model. The Gran Dolina site TD8 level, dated to 0.7−0.6 Ma, is taken as representative of the period during which Atapuerca was apparently not occupied by humans. Conditions at TD8 are compared with those of the previous period, represented by the TD6-2 level, which has yielded abundant evidence of intense human occupation. The results show that survival opportunities for a hypothetical human population were lower at TD8 than they were at TD6-2. Increased resource competition between secondary consumers arises as a possible explanation for the absence of human occupation at Atapuerca in the early Middle Pleistocene.     

The vegetation on screes—A synopsis of higher syntaxa in Europe

A synopsis of high-rank syntaxa of scree vegetation with an accompanying list of plant communities is presented. The classification of scree vegetation in only one broadly conceived class, theThlaspietea rotundifolii, throughout Europe is a new concept. The vegetation on screes was classified into 8 major groups (17 orders and 42 alliances) according to their altitudinal range and the chemistry of the parent material. Brief information on ecological conditions, phytogeographical patterns, and altitudinal distribution are given. The characteristics and important diagnostic taxa for each alliance and order classified within theThlaspietea rotundifolii are given.     

The longitudinal distribution of riverine benthos: A river dis-continuum?

We used several techniques to analyze 10–11 collections from each of 13 stations along a mountain stream gradient to examine the hypothesis that there was a statistically significant (p < 0.05) uniform downstream gradient in benthic distribution. Random skewer techniques suggested that there was a significant downstream gradient of individuals per species, but only a weak gradient in species per station, and no gradient in functional guild composition. Ordination and clustering of either taxonomic or functional guild data suggested the existence of four longitudinally-defined groups of stations. Rarefaction curves also implied longitudinal groupings, with differences among groups implying species replacement than changes in organism numbers. Two species replacement indexes confirmed that suggestion. In summary, the distribution of the benthos in the creek may best be characterized as a punctuated gradient where gradual downstream changes in community composition are punctuated by sudden shifts to new community types. This punctuated gradient appears caused by changes in stream physical and chemical characteristics; the rapid nature of the changes hampers the interpretation of longitudinal analyses. Techniques such as random skewers and cluster analysis of rarefied samples will prove helpful in discerning pattern in stream benthos.     

The role of necroptosis in cancer: A double-edged sword?

Necroptosis is a programmed, caspase-independent cell death that is morphologically similar to necrosis. Unlike apoptosis, necroptosis evokes inflammatory responses by releasing damage-associated molecular patterns. Recent studies suggest that tumor undergoes necroptosis in vivo and necroptosis has pro- or anti-tumoral effects in cancer development and progression. Furthermore, triggering necroptosis in tumor cells has been explored as a potential therapeutic strategy against cancer. Here, we will review the recent research progress of necroptosis in conferring anti- or pro-tumoral effects and its potential application in cancer therapy.     

The Early-Middle Pleistocene faunal assemblages of Gesher Benot Ya'aqov: Inter-site variability

This study investigates faunal remains from the site of Gesher Benot Ya‘aqov, analyzing how hominins may have utilized vertebrates and exploring paleoenvironments during the Early and Middle Pleistocene. Based on analyses of a range of vertebrates, results show that the species distribution of terrestrial vertebrates (microvertebrates and mammals) at the site of Gesher Benot Ya‘aqov shows relative stasis above the Matuyama-Brunhes Boundary (MBB) (0.78 Ma). However, consistency in faunal remains at the site reflecting stasis does not seem to reflect accurately the paleoenvironment. Marked changes are demonstrable in the lake-margin sedimentary background, archaeological remains, and agents of accumulation and damage, as well as in the density of medium-large mammals. This study emphasizes the significance of studying assemblages as a whole rather than the species representation on its own.     

The Pro-inflammatory Role of TGFβ1: A Paradox?

TGFβ1 was initially identified as a potent chemotactic cytokine to initiate inflammation, but the autoimmune phenotype seen in TGFβ1 knockout mice reversed the dogma of TGFβ1 being a pro-inflammatory cytokine to predominantly an immune suppressor. The discovery of the role of TGFβ1 in Th17 cell activation once again revealed the pro-inflammatory effect of TGFβ1. We developed K5.TGFβ1 mice with latent human TGFβ1 overexpression targeted to epidermal keratinocytes by keratin 5. These transgenic mice developed significant skin inflammation. Further studies revealed that inflammation severity correlated with switching TGFβ1 transgene expression on and off, and genome wide expression profiling revealed striking similarities between K5.TGFβ1 skin and human psoriasis, a Th1/Th17-associated inflammatory skin disease. Our recent study reveals that treatments alleviating inflammatory skin phenotypes in this mouse model reduced Th17 cells, and antibodies against IL-17 also lessen the inflammatory phenotype. Examination of inflammatory cytokines/chemokines affected by TGFβ1 revealed predominantly Th1-, Th17-related cytokines in K5.TGFβ1 skin. However, the finding that K5.TGFβ1 mice also express Th2-associated inflammatory cytokines under certain pathological conditions raises the possibility that deregulated TGFβ signaling is involved in more than one inflammatory disease. Furthermore, activation of both Th1/Th17 cells and regulatory T cells (Tregs) by TGFβ1 reversely regulated by IL-6 highlights the dual role of TGFβ1 in regulating inflammation, a dynamic, context and organ specific process. This review focuses on the role of TGFβ1 in inflammatory skin diseases.     

The gastrointestinal tract: A major site of antioxidant action?

Diets rich in fruits and vegetables delay the onset of many age-related diseases, and contain a complex mixture of antioxidants (including ascorbate, carotenoids, vitamin E and other phenolics such as the flavonoids). However, diet also contains pro-oxidants, including iron, copper, H₂O₂, haem, lipid peroxides and aldehydes. Nitrite is frequently present in diet, leading to generation of reactive nitrogen species in the stomach. In considering the biological importance of dietary antioxidants, attention has usually focussed on those that are absorbed through the gastrointestinal tract into the rest of the body. In the present paper we develop the argument that the high levels of antioxidants present in certain foods (fruits, vegetables, grains) and beverages (e.g. green tea) play an important role in protecting the gastrointestinal tract itself from oxidative damage, and in delaying the development of stomach, colon and rectal cancer. Indeed, carotenoids and flavonoids do not seem to be as well absorbed as vitamins C and E. Hence their concentrations can be much higher in the lumen of the GI tract than are ever achieved in plasma or other body tissues, making an antioxidant action in the GI tract more likely. Additional protective mechanisms of these dietary constituents (e.g. effects on intercellular communication, apoptosis, cyclooxygenases and telomerase) may also be important.     

What caused extinction of the Pleistocene megafauna of Sahul?

During the Pleistocene, Australia and New Guinea supported a rich assemblage of large vertebrates. Why these animals disappeared has been debated for more than a century and remains controversial. Previous synthetic reviews of this problem have typically focused heavily on particular types of evidence, such as the dating of extinction and human arrival, and have frequently ignored uncertainties and biases that can lead to misinterpretation of this evidence. Here, we review diverse evidence bearing on this issue and conclude that, although many knowledge gaps remain, multiple independent lines of evidence point to direct human impact as the most likely cause of extinction.     

An ecological map of Europe: why and how?

After a recall of the recent emergence of the great ecological problems on the scale of the European continent and of the privileged use of vegetation maps as an ecological tool, a cartographic synthesis of the main plant formations in Europe is submitted on the basis of a hierarchized and numerized nomenclature of the vegetation units. Examples of connections between vegetation and ecology, as suggested or facilitated by this map, are given: use of the monthly ombrothermic diagrams as a privileged tool, thermic limits of the boreal zone, indicative value of the Mediterranean xerothermic area, predictive models of the geographical shifts of the great ecosystems according to the expected climate changes.