Postcranial adaptation and evolution in lorisidae

With the exception of leaping, lorises and galagos move in many similar ways although frequencies and styles differ. This peculiar locomotor distinction in two closely related subfamilies has profoundly altered their respective postcranial anatomies from their common ancestor. A comparison of postcranial adaptation in extant forms shows that lorises and galagos differ somewhat in forelimb mobility, but are more fundamentally disparate in hindlimb adaptation. Inferences concerning locomotor adaptation in the lorisid fossil record indicate a more generalized locomotor pattern which is more like that of extant cheirogaleids than either living galagos or lorises. Thus, vertical clinging and leaping in galagines and the slow-climbing and suspensory movements of lorisines appear to be evolutionarily recent innovations from a more generalized locomotor past.     

Location of cell cycle regulators cyclin B1, cyclin A, PCNA, Ki67 and cell cycle inhibitors p21, p27 and p57 in human first trimester placenta and deciduas

Although placental development and implantation depend on the coordination of trophoblast proliferation, differentiation and invasion, little is known about the cell cycle regulators that govern the control of these events. The hypothesis that the coordinated expression of cell cycle progression and inhibition factors will determine whether cytotrophoblasts proliferate or undergo cell cycle arrest or cell cycle exit allowing subsequent differentiation was tested. The cell cycle promotors cyclin A, cyclin B1, PCNA, Ki67 and the cell cycle inhibitors p21, p27 and p57 were immunolocalized in tissue sections of first trimester pregnancies (weeks 6 and 9–12). Double staining with cytokeratin 7 allowed unambiguous identification of extravillous cytotrophoblast (EVT) in the decidua. Villous cytotrophoblasts were immunolabelled for Ki67 and cyclin A but only few were stained with anti-cyclin B1. The syncytiotrophoblast was devoid of immunoreactivity for any of the cell cycle progression factors. It expressed especially p21, whereas p27 and p57 were predominantly found in villous cytotrophoblasts. PCNA, Ki67, cyclin A and cyclin B1 were immunolocalized in proximal and distal EVTs of anchoring villi and in EVT which had invaded the upper decidual segments. All EVTs strongly expressed p27 and p57, but not p21. These data clearly suggest different functions for p21, p27 and p57 in placental development with distinct roles for p21 and p57 in syncytiotrophoblast and EVT differentiation, respectively. p27 appears to be involved in both the processes. The results may also challenge the concept of differential mitotic activity in the proximal and distal parts of the first trimester cytotrophoblast cell column, but more functional studies are clearly needed. The presence of p27 and p57 in EVT cells, which invade the deciduas deeply, may account for the loss of mitogenic potential of these cells.     

A description of the smallest Triodon on record (Teleostei: Tetraodontiformes: Triodontidae)

The smallest known specimen (20mm standard length: SL) of Triodon macropterus Lesson is described and illustrated. It is easily distinguished from superficially similar tetraodontid and diodontid larvae or early juveniles of comparable size by the following characters: separate premaxillae in conjunction with the fused dentaries; the presence of multicuspid spinoid scales; the jet-black mark in front of the soft dorsal fin; the developing pelvis, which is visible through the distended skin of the belly; and the presence of a number of procurrent caudal fin rays. The small Triodon differs from the adult in possessing a huge head that measures 45% SL (vs. 28.5–32.7% in adult), the absence of the characteristic dewlap with the conspicuous lateral ocellus, and the structure of the scales and nostrils.     

Paleoceanography of the Gulf of Alaska during the past 15,000 years: Results from diatoms, silicoflagellates, and geochemistry

High-resolution records of diatoms, silicoflagellates, and geochemistry covering the past 15,000 years were studied in three cores from the Gulf of Alaska (GOA). Core EW0408-85JC in an oceanic setting on the Kayak Slope displays a paleoceanographic record similar to that at several locations on the California margin during deglaciation. Biologic productivity as reconstructed using geochemical and microfossil proxies increased abruptly during the Bølling–Alleröd (Bø–Al) warm interval (14.7–12.9 cal ka), declined during the Younger Dryas (YD) cold interval (12.9 to 11.7 cal kyr BP), and rose again during the earliest Holocene. At this site, the record after ~ 11 cal kyr BP is dominated by oceanic diatoms and silicoflagellates, with geochemical proxies displaying more subtle variation.Cores EW0408-66JC in the Yakobi Sea Valley near Cross Sound and EW0408-11JC in the Gulf of Esquibel contain an expanded, composite record along the southeast Alaskan margin. Core 66JC contains a detailed record of the Bø–Al and YD. Diatoms and silicoflagellates indicate that coastal upwelling and biosiliceous productivity were strong during the Bø–Al but declined during the YD. Sea ice-related diatoms increased in abundance during the YD, indicating cooler, but less productive waters.The glacial to biogenic marine sediment transition in core 11JC occurs at 1280 cmbsf (centimeters below sea floor), probably representing rising sea level and deglaciation early in the Bø–Al. Freshwater and sea-ice related diatoms are common in the lower part of the core (Bø–Al and YD), but upwelling-related diatoms and silicoflagellates quickly increased in relative abundance up-core, dominating the record of the past 11,000 years. Low oxygen conditions in the bottom water as reconstructed using geochemical proxies (U and Mo concentration) were most intense between ~ 6.5 and 2.8 cal kyr BP, the beginning of which is coincident with increases in abundance of upwelling-related diatoms.The records from these three cores jointly thus made it possible to reconstruct paleoclimatic and paleoceanographic conditions at high northern Pacific latitudes during the last 15 kyr.     

北祁连山东段早石炭世棘鱼类、辐鳍鱼类和软骨鱼类--北祁连山东段石炭纪鱼类序列研究之一

对甘肃靖远一带和内蒙古自治区黑山地区早石炭世前黑山组、臭牛沟组和靖远组中三亚纲鱼类微体化石进行了形态学和古组织学研究。这些化石涉及 7个目或亚目 ,含 4属 4种 ,其中有 2新种。文中记述的属均为全球广布的属。建立了 3个早石炭世鱼类组合 ,这是我国早石炭世第一个鱼类组合序列。辐鳍鱼类和软骨鱼类中 2个目的化石均为我国早石炭世鱼类的首次记录     

Nubian Complex strategies in the Egyptian high desert

Systematic survey by the Abydos Survey for Paleolithic Sites project has recorded Nubian Complex artifact density, distribution, typology, and technology across the high desert landscape west of the Nile Valley in Middle Egypt. Our work contrasts with previous investigations of Nubian Complex settlement systems in Egypt, which focused on a small number of sites in the terraces of the Nile Valley, the desert oases, and the Red Sea Mountains. Earlier research interpreted the Nubian Complex, in particular, as a radiating settlement system that incorporated a specialized point production. Our high desert data, however, indicate that the Nubian Complex associated with early modern humans in this region of the high desert reflects a circulating, rather than a radiating, settlement system, and that point production has been over-emphasized. Data available from our work, as well as sites investigated by others, do not conclusively identify Nubian Complex behavioral strategies as modern. These data, however, do contribute to the understanding of landscape use by early modern human populations living along the Nile Valley Corridor route out of Africa.     

安徽淮南大居山的早更新世反刍类

继在安徽淮南大居山发现晚中新世老洞哺乳动物群和新洞早上新世哺乳动物群后,1998年在老洞西侧又发现了西裂隙哺乳动物群。据对所出土的化石标本所作的整理研究,大居山西裂隙的反刍类动物化石有4个种：狍后麂Metacervulus capmolinus、山西轴鹿Axis shan- sius、布氏真枝角鹿Eucladoceros boulei和半牛未定种Hemibos?sp．,全部为绝灭种。它们所指示的地质年代为早更新世早期;所显示的动物群面貌为带有北方色彩的南、北方过渡带特色;所反映的生态环境为北温带森林景观,山谷间有少量密林,山脚下有局部草地。反刍类中山西轴鹿的标本数量最多,说明这个种是大居山西裂隙动物群中的优势种群。西裂隙动物群中的反刍类化石的另一个特点是未成年个体占有较大的比例,与河流冲击扇沉积中的动物年龄结构有很大的差别,也许指示大居山西裂隙是食肉动物存储和食用它们猎物的场所或这些反刍类的天然陷阱。     

Population differentiation in the context of Holocene climate change for a migratory marine species,the southern elephant seal

Understanding observed patterns of connectivity requires an understanding of the evolutionary processes that determine genetic structure among populations, with the most common models being associated with isolation by distance, allopatry or vicariance. Pinnipeds are annual breeders with the capacity for extensive range overlap during seasonal migrations, establishing the potential for the evolution of isolation by distance. Here, we assess the pattern of differentiation among six breeding colonies of the southern elephant seal, Mirounga leonina, based on mtDNA and 15 neutral microsatellite DNA markers, and consider measures of their demography and connectivity. We show that all breeding colonies are genetically divergent and that connectivity in this highly mobile pinniped is not strongly associated with geographic distance, but more likely linked to Holocene climate change and demographic processes. Estimates of divergence times between populations were all after the last glacial maximum, and there was evidence for directional migration in a clockwise pattern (with the prevailing current) around the Antarctic. We discuss the mechanisms by which climate change may have contributed to the contemporary genetic structure of southern elephant seal populations and the broader implications.     

The Involvement of Upregulation and Translocation of Phospho-Rb in Early Neuronal Apoptosis Following Focal Cerebral Ischemia in Rats

The aim of this study was to investigate the temporal and spatial relationship between phospho-Rb (ser 795) and neuronal apoptotic death in rats subjected to transient focal cerebral ischemia. We found increased phosphorylation of Rb and translocation from neuronal nucleus to cytoplasm in the penumbra zone at 12 h, 1 day, 3 days and 7 days after middle cerebral artery occlusion (MCAO)/reperfusion, compared with sham-operated controls. At 12 h and 1 day, phospho-Rb appeared to be colocalizated with TUNEL staining in neurons, but staining was not colocalizated at 3 days and 7 days. These results demonstrated that cytoplasmic translocation of phospho-Rb from nucleus of neurons occurs in potential apoptotic neurons in the early stages of ischemia/reperfusion, suggesting that the Rb pathway may only be involved in early neuronal apoptosis and may be not an apoptotic signal in the late stages of transient cerebral ischemia. Ying Yu and Xiang Luo contributed equally to this work.