Pleistocene Plant Fossils in and near La Selva Biological Station, Costa Rica1

Radiocarbon dating and ⁴⁰Ar/³⁹Ar analysis of overlying tephra indicate that plant fossil assemblages exposed by stream erosion and well construction in and near La Selva Biological Station in eastern lowland Costa Rica are Pleistocene in age. We identified plant taxa based on wood, leaves, fruits, seeds, pollen, and spores examined from three sites at ca 30 m elevation. Extrapolating from modern ranges and surface temperature lapse rates suggests paleotemperatures 2.5–3.1°C cooler than at present     

Extreme climatic events reduce ocean productivity and larval supply in a tropical reef ecosystem

Increasing ocean temperatures due to global warming are predicted to have negative effects on coral reef fishes. El Niño events are associated with elevated water temperatures at large spatial (1000s of km) and temporal (annual) scales, providing environmental conditions that enable temperature effects on reef fishes to be tested directly. We compared remote sensing data of sea surface temperature (SST) anomalies, surface current flow and chlorophyll‐a (Chl‐a) concentration with monthly patterns in larval supply of coral reef fishes in nearshore waters around Rangiroa Atoll (French Polynesia) from January 1996 to March 2000. This time included an intense El Niño (April 1997–May 1998) event between two periods of La Niña (January–March 1996 and August 1998–March 2000) conditions. There was a strong relationship between the timing of the El Niño event, current flow, ocean productivity (as measured by Chl‐a) and larval supply. In the warm conditions of the event, there was an increase in the SST anomaly index up to 3.5 °C above mean values and a decrease in the strength of the westward surface current toward the reef. These conditions coincided with low concentrations of Chl‐a (mean: 0.06 mg m^?3, SE ± 0.004) and a 51% decline in larval supply from mean values. Conversely, during strong La Niña conditions when SST anomalies were almost 2 °C below mean values and there was a strong westward surface current, Chl‐a concentration was 150% greater than mean values and larval supply was 249% greater. A lag in larval supply suggested that productivity maybe affecting both the production of larvae by adults and larval survival. Our results suggest that warming temperatures in the world's oceans will have negative effects on the reproduction of reef fishes and survival of their larvae within the plankton, ultimately impacting on the replenishment of benthic populations.     

The chalicothere <Emphasis Type="Italic">Metaschizotherium bavaricum</Emphasis> (Perissodactyla,Chalicotheriidae, Schizotheriinae) from the Miocene (MN5) Lagerstätte of Sandelzhausen (Germany): description,comparison, and paleoecological significance

Within the fossil collection from the Sandelzhausen Lagerstätte in the Upper Freshwater Molasse near Mainburg, Germany, are remains of the schizotheriine chalicothere Metaschizotherium bavaricum, von Koenigswald, 1932. This new material includes elements from a large part of the body, and allows the dentition and postcranial skeleton of Metaschizotherium to be described in detail for the first time. At approximately 16 Ma (MN5), M. bavaricum is now the best-known Early and Middle Miocene European schizotheriine and is important for comparative studies. It differs to some degree from earlier Miocene (MN2–MN4) European material attributed to Moropus sp. or Metaschizotherium wetzleri (Kowalewsky, 1873) and to a larger degree from the Late Miocene species Ancylotherium pentelicum (Gaudry and Lartet, 1856). At Sandelzhausen, M. bavaricum apparently lived in a moist forested environment, where it probably fed on leaves, fruit, and seeds. Members of the Chalicotheriinae, such as Anisodon and Chalicotherium, are not found at Sandelzhausen and may not have been present in Europe at this time. M. bavaricum, like other Schizotheriinae, did not have the bizarre gorilla-like proportions of the Chalicotheriinae. Instead, its general body proportions resemble those of contemporary schizotheriine chalicotheres on other continents, for example, Moropus from North America. M. bavaricum is slightly smaller than the type species of Metaschizotherium, M. fraasi von Koenigswald, 1932 (MN6–MN7) and differs from it in small ways that are still being explored as variation within and differences between these species are clarified. The schizotheriine chalicothere from La Grive St.-Alban (France) referred to M. fraasi by von Koenigswald (Palaeontographica, Beitrage zur Naturgeschichte der Vorzeit 8:1–24, 1932) and Viret (Nouvelles Archives Musée d’Histoire Naturelle de Lyon 6:53–81, 1961) should be restudied and referred to a different taxon.     

Tumor-associated autoantibodies as diagnostic and prognostic biomarkers

In the process of tumorigenesis, normal cells are remodeled to cancer cells and protein expression patterns are changed to those of tumor cells. A newly formed tumor microenvironment elicits the immune system and, as a result, a humoral immune response takes place. Although the tumor antigens are undetectable in sera at the early stage of tumorigenesis, the nature of an antibody amplification response to antigens makes tumor-associated autoantibodies as promising early biomarkers in cancer diagnosis. Moreover, the recent development of proteomic techniques that make neo-epitopes of tumor-associated autoantigens discovered concomitantly has opened a new area of ‘immuno-proteomics’, which presents tumor-associated autoantibody signatures and confers information to redefine the process of tumorigenesis. In this article, the strategies recently used to identify and validate serum autoantibodies are outlined and tumor-associated antigens suggested until now as diagnostic/prognostic biomarkers in various tumor types are reviewed. Also, the meaning of autoantibody signatures and their clinical utility in personalized medicine are discussed. [BMB Reports 2012; 45(12): 677-685]     

Inhibition of glutamate-induced delayed calcium deregulation by 2-APB and La3+ in cultured cortical neurones

Exposure of neurones in culture to excitotoxic levels of glutamate results in an initial transient spike in [Ca2+]i followed by a delayed, irreversible [Ca2+]i rise governed by rapid kinetics, with Ca2+ originating from the extracellular medium. The molecular mechanism responsible for the secondary Ca2+ rise is unknown. Here, we report that the delayed Ca2+ entry in cortical neurones is diminished by 2-aminoethoxydiphenyl borate (2-APB: IC50 = 62 +/- 9 microm) and La3+ (IC50 = 7.2 +/- 3 microm), both known to inhibit transient receptor potential (TRP) and store-operated Ca2+ (SOC) channels. Application of thapsigargin, however, failed to exacerbate the delayed Ca2+ deregulation, arguing against a store depletion event as the stimulus for induction of the secondary [Ca2+]i rise. In addition, these neurones did not exhibit SOC entry. Unexpectedly, application of ryanodine or caffeine significantly inhibited glutamate-induced delayed Ca2+ deregulation. In basal Ca2+ entry experiments, La3+ and 2-APB modulated the rapid rise in [Ca2+]i caused by exposure of neurones to Ca2+ after pre-incubating in a calcium-free medium. This basal Ca2+ influx was mitigated by extracellular Mg2+ but not aggravated by thapsigargin, ryanodine or caffeine. These results indicate that 2-APB and La3+ influence non-store-operated Ca2+ influx in cortical neurones and that this route of Ca2+ entry is involved in glutamate-induced delayed Ca2+ deregulation.     

La3+-promoted proliferation is interconnected with apoptosis in NIH 3T3 cells

Lanthanum ion (La(3+)) has been reported to affect proliferation or apoptosis of different cells. In the present study, La(3+) was confirmed to promote both proliferation and apoptosis of NIH 3T3 cells at the same concentrations. La(3+) was shown to promote proliferation by helping the cells to pass through the G1/S restriction point and enter S phase, however, the proliferating cells induced by incubation with La(3+) eventually underwent apoptosis. The proliferation and apoptosis of NIH 3T3 cells induced by La(3+) were well correlated with cell cycle alterations. La(3+) caused the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2; while inhibition of ERK phosphorylation by 2'-amino-3'-methoxyflavone (PD98059) suppressed both proliferation and apoptosis induced by La(3+). Based on the above experimental results, we postulated that La(3+)-promoted proliferation of NIH 3T3 cells could be interconnected with the cell apoptosis, possibly through cell cycle machinery. Our results thus support the recent hypothesis that proliferation and apoptosis of cell are intrinsically coordinated.     

Population history of native groups in pre- and postcontact Spanish Florida: aggregation, gene flow, and genetic drift on the Southeastern U.S. Atlantic coast

Evolutionary trends and population history and structure are discussed for a series of late prehistoric and historic-period skeletal samples from the Georgia coast and interior (the Guale). Phenotypic dental measurement data were collected for nine samples from the late prehistoric (AD 1200-1400) and historic (AD 1608-1702) periods and subjected to population genetic and statistical analyses. The primary trends were for an increase in tooth size through time, and for an initial increase in dental variability in the early historic period, followed by a subsequent decline in dental variability in the late historic period. Given the increasing stress levels, evidenced by previous bioarchaeological analyses (Larsen [2001] Bioarchaeology of Spanish Florida, Gainesville: University Press of Florida), an environmental explanation for the increase in tooth size is unlikely. It is proposed that the early historic period witnessed aggregation and gene flow with extraregional populations, possibly African slaves or nonlocal Native American population groups. The late historic period may have experienced significant loss of phenotypic variability due to genetic drift. In both time periods, the evolutionary mechanism increased average tooth size, with independent variance effects.Because microevolutionary trends obscure patterns of gene flow and population ancestry, the data were detrended following Konigsberg ([1990a] Hum. Biol. 62:49-70), and submitted to standard population genetic analyses (Relethford et al. [1997] Hum. Biol. 69:443-465). Analysis of the precontact samples in isolation (Irene Mound, Irene Mortuary, and an aggregate coastal sample) indicated little genetic microdifferentiation (F(ST) = 0.008), limited extralocal gene flow, and a small distinction between interior and coastal samples. The inclusion of the historic data dramatically increased variability levels (F(ST) = 0.019). The analysis of extralocal gene flow indicates that the late mission period experienced significantly less external gene flow, which is consistent with historic models that suggest the social organization of the Guale during this time period may have been significantly altered. Genetic distances also indicate a primary division between inland and coastal precontact samples and a maintenance of biological populations along the coast. In other words, the coastal, early historic, and late historic period samples are phenotypically homogeneous, supporting the notion that the mission populations were drawn from the local population base. The late mission period sample was also, however, more closely related to the interior samples. This may suggest that the late mission period population was an aggregate sample composed of both remnant interior and coastal population groups.     

The dentition of the "old man" of La Chapelle-aux-Saints and inferences concerning Neandertal behavior

It has been suggested that the fossil Neandertal from La Chapelle-aux-Saints was so toothless that he would have had to have his food pre-chewed or otherwise prepared for him. This has also led to the inference that a high level of altruistic social behavior was characteristic of Neandertals. This appears to be in keeping with a current trend among anthropologists to upgrade the cultural and evolutionary status of Neandertals. Close examination of the recovered teeth and the condition of the alveoli indicates that the "old man" of La Chapelle-aux-Saints had upper and lower incisor, canine and premolar teeth on the left side intact and probably in occlusion, and that the same was true of these teeth in the right maxilla. Mandibular incisors, canine, and first premolar had probably been lost to a tumor or abscessing on the right side, but this pathology may have developed near the time of death. The right mandibular second premolar was probably functional, although tilted similarly to the intact premolar on the left. It is very unlikely that the individual was unable to chew food. The dentition thus gives no reliable evidence of altruistic behavior by his cohorts. This study may also relate to hypotheses concerning the ancestry of anatomically modern humans.