bluuebunny/crossref_metadata_2025_split huggingface dataset:
Middle Devonian microfloras and megafloras from western Argentina and southern Bolivia: their importance in the palaeobiogeographical and palaeoclimatic evolution of western Gondwana
Authors: di Pasquo M. , Amenábar C. R. , Noetinger S. 
Published: April 2009

Abstract

The study of microfloras and megafloras from western Argentina and southern Bolivia presented here extends our knowledge of the biodiversity and succession of floristic events during the Middle Devonian, and hence improves the current biostratigraphy. Among floral remains, species attributable to ‘
Haplostigma
’ are mostly recorded from the same
Grandispora pseudoreticulata
and other palynomorph-bearing sections at Balapuca (southern Bolivia) and Del Chaco and La Cortadera creeks in the Precordillera of Argentina. The northernmost record of
Grandispora pseudoreticulata
is recorded from a third palynoassemblage from the Pando x-1 corehole of northern Bolivia. A great similarity among all these assemblages (notably abundant
Grandispora pseudoreticulata
) suggests the identification of terrestrial connections, or at least proximity, of these local areas and other regions in South America during the Givetian. Comparison with other contemporary Gondwanan palynofloras shows cosmopolitan species (e.g.
Geminospora lemurata
,
Samarisporites triangulatus
,
Archaeozonotriletes variabilis
,
Chelinospora concinna
) along with some others with more restricted distribution (e.g.
Grandispora pseudoreticulata
,
Leiotriletes balapucensis
,
Acinosporites ledundae
). This pattern defines an Afro-South American Subrealm, which most likely results from the effects of palaeolatitude and, in a lesser way, local palaeoenvironmental conditions. On the other hand, such a level of cosmopolitanism supports previous palaeogeographical reconstructions where a narrow Rheic Ocean was developed between Euramerica and the northern parts of Africa and South America.
Late Devonian echinoderms from the Hongguleleng Formation of northwestern China
Authors: Webster G. D. , Waters J. A. 
Published: April 2009

Abstract
The Late Devonian, Famennian, Hongguleleng Formation of northwestern China has yielded one of the most diverse echinoderm faunas known from China. New collections and re-evaluation of earlier collections results in recognition of new taxa, increases the known diversity, provides new morphological information on some of the previously reported taxa, and provides new information on the affinity of the Late Devonian echinoderms of the Hongguleleng Formation.

New crinoid taxa introduced are
Gnarycrinus lanei
n. gen., n. sp.,
Anamesocrinus tieni
n. sp.,
Histocrinus
?
chenae
n. sp.,
Eumhacrinus tribrachiatus
n. gen., n. sp.,
Sostronocrinus aberratus
n. sp. and
Labrocrinus granulatus
n. gen., n. sp. One new species of blastoid,
Hadroblastus liaoi
, n. sp. is described.

Previous reports listed 46 echinoderms from the Hongguleleng Formation, including 13 blastoids and 33 crinoids. An additional 11 crinoid species bring the total crinoids to 44 species assigned to 32 genera. Similarly, the one additional species of blastoid brings the totals to 14 species assigned to 12 genera. The new echinoderms described herein include the first report of a dimerocrinitid, amphoracrinid, allagacrinid, glossocrinid, histocrinid, cercidiocrinid, dactylocrinid and neoschismatid from the Devonian of northwestern China. Additional morphologic information is provided for three of the previously described taxa and a revision of species assigned to
Grabauicrinus
is proposed.

The crinoids and blastoids suggest closer affinity with Mississippian faunas than with Devonian faunas, and with North American faunas than European faunas. Collectively the blastoid and crinoid faunas from the Hongguleleng indicate that rediversification happened rapidly after extinction in contrast to current suggestions of a long interval of lowered origination following these extinction events.
Devonian ecological-evolutionary subunits in the Appalachian Basin: a revision and a test of persistence and discreteness
Authors: Brett C. E. , Ivany L. C. , Bartholomew A. J. , DeSantis M. K. , Baird G. C. 
Published: April 2009

Abstract
New data compilations for successive formation scale intervals, approximately third-order sequences, permit a statistical characterization of the ecological–evolutionary subunits (EESUs) or faunas of the Latest Silurian to mid-Late Devonian interval in the Appalachian Basin. Cluster analysis using the Jaccard coefficient of similarity show that certain formations cluster tightly together on the basis of faunal composition while in other cases units are sharply set off from superseding units. This result indicates both the coherence of faunal composition within EESUs and the discreteness of their boundaries. The results also require minor revision of EESUs previously delineated, including the addition of three new units. The Esopus Formation is designated as a distinct unit separate from the Schoharie on the basis of brachiopods from shallow water facies of the Skunnemunk outlier in New York; in addition, a short-lived Stony Hollow fauna is recognized in shallow shelf facies of the Union Springs Formation and coeval units (formerly referred to as the lower Marcellus Formation) and the lower transgressive beds of the overlying Oatka Creek Formation. This fauna, consisting of subtropical Old World Realm (OWR) emigrants, is distinctive from both the underlying Onondaga fauna and that of the overlying Hamilton Group. Moreover, the Tully Formation presents another case of a short-lived incursion of tropical OWR taxa followed by the extermination of this fauna and reappearance of a suite of typically Hamilton taxa. This case illustrates that EESUs may persist globally despite their local extermination or emigration from a large region, such as the Appalachian Basin.
Review of the broader context of EESU turnover suggests that these crises are geologically rapid and synchronous. Moreover, most of the Devonian EESU boundaries coincide with recognized global bioevents, within the limits of combined biostratigraphic and sequence stratigraphic resolution. Hence, these crises, although perhaps locally accentuated in the Appalachian Basin, are allied to global causes. They appear mostly to be associated with rapid rises in sea level, periods of widespread climatic change and hypoxic events in basinal areas.
The Siegenian delta: land-sea transitions at the northern margin of the Rhenohercynian Basin
Authors: Stets J. , Schäfer A. 
Published: April 2009

Abstract
Analysis, interpretation and reconstruction of different depositional palaeoenvironments in the land–sea transition zone of the huge Lower Devonian siliciclastic delta system at the northern margin of the Rhenohercynian Basin (Central European Variscides, Germany) are the main subjects of this paper. Seven representative columnar sections have been taken at larger outcrops in the Mid-Rhine region. They furnished the main criteria for this analysis. The understanding and interpretation of the different depositional palaeoenvironments have been supported by regional geological lithological and biostratigraphical data.
The sedimentary processes of distal meandering fluvial systems that gradually passed into fluvial-dominated deltaic systems of the elongate bird-foot type have been recognized. Lower delta slope to delta-foot plain conditions have been detected in a subtidal environment probably down to 100 m of former water depth. Thus, the Siegenian delta must have had a low inclined but wide slope down to the basin floor.
Palaeoclimatic conditions at a latitude of about 10 to 30° south, in the basinal as well as in the source area of the Old Red Continent in the north, controlled the input of siliciclastic detritus as well as the depositional processes in the basin. Moreover, steady subsidence and an intermittent sea level played a prominent role during sedimentation. They held this system in balance for more than seven million years.
Frasnian reef evolution and palaeogeography, SE Lennard Shelf, Canning Basin, Australia
Authors: George Annette D. , Trinajstic Kate M. , Chow Nancy 
Published: April 2009

Abstract

Frasnian reef complexes of the southeastern Lennard Shelf (northern Canning Basin) developed on tilt-block highs and their evolution was controlled by fault-related subsidence. Tectonic control on relative sea-level changes was, therefore, a major factor influencing Early–Middle Frasnian palaeogeography of the Lennard Shelf. However, palaeogeographic reconstruction is not consistent with simple landward (northward) backstepping and younging of reef complexes in response to basin extension and subsidence of fault blocks. Using a sequence-stratigraphic approach, in conjunction with sedimentological and biostratigraphic data, we propose that two neighbouring fault blocks (Lawford area on the eastern side of Bugle Gap and the Hull platform to the north) record a similar history and that the reef complexes on those blocks were initiated at similar times. Seven phases of Early–Middle Frasnian platform growth (Fr2–8) are identified. All are bounded by third-order flooding surfaces associated with backstepping of platform margins and three surfaces (defined by conodont Zone 4, Zone 6 and late Zone 6) correlate across the two fault blocks. Only one sequence boundary has been clearly identified and a second relative sea-level fall is proposed based on a major collapse event following progradation and associated coarse siliciclastic facies. We propose that the correlation of flooding events across the SE Lennard Shelf is related to episodes of basin-margin faulting centred on the large, long (
c
. 25 km) faults which border these blocks (shelf-parallel faults for the Lawford block and an oblique north-trending transfer zone for the Hull block). There is limited evidence for relative sea-level falls and those recognized most likely resulted from eustatic events. The correlation between the Lawford block and Hull platform suggests linkage between major NW-trending shelf-parallel and oblique transfer faults and an evolved rift system by the Early Frasnian.
Distribution, geometry and palaeogeography of the Frasnian (Late Devonian) reef complexes of Banks Island, NWT, western arctic, Canada
Authors: Copper P. , Edinger E. 
Published: April 2009

Abstract

Following the collapse of the >2000 km long Givetian (Middle Devonian) Inuitian/Ellesmere carbonate platform factory in arctic Canada, within the 0° to 10° equatorial palaeolatitudes north, the only Frasnian reefs in high arctic Canada retreated westwards, confined to northeastern Banks Island. These reefs, numbering well over 130, and dominated by corals and stromatoporoid sponges, were spread over
c
. 5000 km
2
, within the 220 m thick Mercy Bay Formation. Reefs were developed at four different stratigraphic levels (termed the A, B, C and D levels) during early and middle Frasnian time, periodically smothered by intervening siliciclastics during sea-level lowstands, and were finally buried by thick siliciclastic sands, silts and muds derived from the east during the late Frasnian. The Frasnian–Famennian boundary is masked within continental, deltaic facies bearing plant remains. The Banks reef and carbonate succession is preserved as horizontally stratified,
in situ
limestones, with the succeeding reefs backsteppping towards the east, in response to cyclic Frasnian sea-level rises. The Banks reefs were developed on the distal lobes of a megadelta, periodically covered by extensive lowland forests that stretched more than 2000 km west from Greenland and Ellesmere Island. Reefs are three-dimensionally preserved, unaffected by diagenesis, dolomitization, major tectonics, vegetative cover or glaciation, and thus display some of the finest, pristine Late Devonian reef complexes known. The reefs represent a range of geometries, from small circular to oval patch reefs a few tens of metres in diameter and <5–10 m thick, to larger prominent tabular (‘reef platform’ style) and domal reef structures >2 km across, or 300–400 m diameter, and 40–60 m thick. Coral and stromatoporoid-rich biostromes also formed a significant part of the reef seascape. Morphology of the reefs leads to an estimation of penecontemporaneous relief of 10–20 m above the prevailing sea floor, with reef-core facies generally dominated by stromatoporoid sponges, and flank facies by a variable mix of colonial tabulate and rugose corals, as well as stromatoporoids. Bryozoans and calcimicrobialites were rare, in contrast to other Late Devonian reefs such as those of the Canning Basin (Australia), or the Guangxi platform (South China); mudmound reef facies, such as seen in Belgium were limited.
Devonian (Emsian to Frasnian) crinoids of the Dra Valley, western Anti-Atlas Mountains, Morocco
Authors: Webster G. D. , Becker R. T. 
Published: April 2009

Abstract

Emsian to Frasnian crinoids are described from pelagic facies of the eastern part of the Dra Valley (Tata area), western Anti-Atlas Mountains, southern Morocco. The crinoids show only minor relationship with previously described crinoids from the Tafilalt and Ma'der areas of the eastern Anti-Atlas. The differences are judged to reflect the different environments of these areas. The Dra Valley hexacrinids show greater affinity with European faunas, whereas the amabilicrinids show greater affinity with North American taxa. New taxa described are
Hexacrinites chenae
sp. nov.,
Dracrinus crenulatus
gen. and sp. nov.,
Coquinacrinus revimentus
gen. and sp. nov, and
Embolocrinus quadruus
gen. and sp. nov.
A re-evaluation of Famennian echinoderm diversity: implications for patterns of extinction and rebound in the Late Devonian
Authors: Waters J. A. , Webster G. D. 
Published: April 2009

Abstract
Critical to understanding long-term trends in diversity is a dataset that is both worldwide in scope and based on a sound taxonomic foundation. In this paper we re-evaluate the Famennian (Late Devonian) echinoderm dataset, which has changed radically in the past decade, and reinterpret patterns of Late Devonian echinoderm extinction and rebound based on these new data. Historically, Famennian (Late Devonian) and earliest Carboniferous echinoderms have been poorly known on a global basis leading to interpretations of prolonged rebound from the Devonian extinction events. Recent discoveries of abundant and diverse Famennian echinoderm faunas from northwestern China, Colorado, Australia and Iran, together with re-examination of previously known echinoderm faunas from Germany and England, have altered drastically our understanding of the patterns of extinction and rebound of Famennian and earliest Carboniferous echinoderm communities. Overall, Famennian echinoderm diversity at the generic level is nearly five times greater than reported in the 2002 Sepkoski compilation, and familial level diversity is more than seven times greater than previously thought. Despite the increases in diversity, Famennian echinoderm faunas show a reduced diversity of camerate crinoids that typify both Middle Devonian and Lower Mississippian faunas and portend the rise of cladid crinoid diversity later in the Carboniferous. Individual Famennian faunas are numerically dominated by blastoids, which also portends trends seen at various times later in the Palaeozoic. In general, we are able to recognize the following trends. Rebound from the Late Devonian extinction events in echinoderms was more rapid than previously thought, but seems to be concentrated in Asia. Palaeogeographically Famennian echinoderms can be grouped into two broad regions: one includes China, Australia and Iran, all of which bordered the Palaeotethys; the other includes regions from Laurussia (Europe and North America) and northern Africa (Morocco).
Regulation of Secondary Antigen-Specific CD8+ T-Cell Responses by Natural Killer T Cells
Authors: Hong Changwan , Lee Hyunji , Park Yoon-Kyung , Shin Junghoon , Jung Sundo , Kim Hoyeon , Hong Seokmann , Park Se-Ho 
Published: April 2009

AbstractThe physiologic function of natural killer T (NKT) cells in adaptive immunity remains largely unknown because most studies have used NKT cell agonists. In the present study, the role of NKT cells during the secondary effector phase was investigated separately from the primary immunization phase via adoptive transfer of differentiated effector T cells into naive recipients. We found that secondary antitumor CD8+ T-cell responses were optimal when NKT cells were present. Tumor-specific CD8+ effector T cells responded less strongly to tumor cell challenge in NKT cell–deficient recipients than in recipients with intact NKT cells. NKT cell–mediated enhancement of the secondary antitumor CD8+ T-cell response was concurrent with increased number and activity of tumor-specific CD8+ T cells. These findings provide the first demonstration of a direct role for NKT cells in the regulation of antigen-specific secondary T-cell responses without the use of exogenous NKT cell agonists such as α-galactosylceramide (α-GalCer). Furthermore, forced activation of NKT cells with α-GalCer during the secondary immune response in suboptimally immunized animals enhanced otherwise poor tumor rejection responses. Taken together, our findings strongly emphasize the importance of NKT cells in secondary CD8+ T-cell immune responses. [Cancer Res 2009;69(10):4301–8]
Disruption of the E2 Gene Is a Common and Early Event in the Natural History of Cervical Human Papillomavirus Infection: A Longitudinal Cohort Study
Authors: Collins Stuart I. , Constandinou-Williams Christothea , Wen Kaisheng , Young Lawrence S. , Roberts Sally , Murray Paul G. , Woodman Ciaran B.J. 
Published: April 2009

Abstract
Integration of high-risk human papillomavirus (HPV) types into the host-cell genome disrupts the HPV regulatory E2 protein, resulting in a loss of negative feedback control of viral oncogene expression; this disruption has been considered a critical event in the pathogenesis of cervical neoplasia, and a potential biomarker of progressive disease. However, using serial samples taken from a cohort of young women who were recruited soon after they first had sexual intercourse, we show that disruption of the E2 gene is a common and early event in the natural history of incident cervical HPV infections. The E2 gene was significantly more likely to be disrupted in women who tested positive for HPV18 in their baseline sample than in those who tested positive for HPV16 [26% versus 58%; relative risk, 2.26; 95% confidence interval (CI), 1.38–3.71; χ2, 9.23; 1 degree of freedom (df); P = 0.002]. Among women with an intact E2 gene in their baseline sample, the median time to first detection of E2 disruption was also shorter for those who tested positive for HPV18 than HPV16 (5.7 versus 10.9 months; hazards ratio, 1.93; 95% CI, 0.84–4.44; χ2, 2.49; 1 df; P = 0.11). This tendency for HPV18 to integrate early, coupled with the substantial reduction in viral load in HPV18-positive samples in which E2 is disrupted, may explain why HPV18-associated disease is often reported to be characterized by minor cytologic changes, which underestimate the severity of the underlying histologic abnormality. [Cancer Res 2009;69(9):3828–32]
PI3K Pathway Activation Mediates Resistance to MEK Inhibitors in KRAS Mutant Cancers
Authors: Wee Susan , Jagani Zainab , Xiang Kay Xiaoqin , Loo Alice , Dorsch Marion , Yao Yung-Mae , Sellers William R. , Lengauer Christoph , Stegmeier Frank 
Published: April 2009

Abstract
The RAS pathway is one of the most frequently deregulated pathways in cancer. RAS signals through multiple effector pathways, including the RAF/mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) kinase (MEK)/ERK MAPK and phosphatidylinositol 3-kinase (PI3K)-AKT signaling cascades. The oncogenic potential of these effector pathways is illustrated by the frequent occurrence of activating mutations in BRAF and PIK3CA as well as loss-of-function mutations in the tumor suppressor PTEN, a negative regulator of PI3K. Previous studies have found that whereas BRAF mutant cancers are highly sensitive to MEK inhibition, RAS mutant cancers exhibit a more variable response. The molecular mechanisms responsible for this heterogeneous response remain unclear. In this study, we show that PI3K pathway activation strongly influences the sensitivity of RAS mutant cells to MEK inhibitors. Activating mutations in PIK3CA reduce the sensitivity to MEK inhibition, whereas PTEN mutations seem to cause complete resistance. We further show that down-regulation of PIK3CA resensitizes cells with co-occurring KRAS and PIK3CA mutations to MEK inhibition. At the molecular level, the dual inhibition of both pathways seems to be required for complete inhibition of the downstream mammalian target of rapamycin effector pathway and results in the induction of cell death. Finally, we show that whereas inactivation of either the MEK or PI3K pathway leads to partial tumor growth inhibition, targeted inhibition of both pathways is required to achieve tumor stasis. Our study provides molecular insights that help explain the heterogeneous response of KRAS mutant cancers to MEK pathway inhibition and presents a strong rationale for the clinical testing of combination MEK and PI3K targeted therapies. [Cancer Res 2009;69(10):4286–93]
Heregulin Regulates Prolactinoma Gene Expression
Authors: Vlotides George , Cooper Odelia , Chen Yen-Hao , Ren Song-Guang , Greenman Yona , Melmed Shlomo 
Published: April 2009

Abstract
To investigate the role of p185her2/neu/ErbB3 signaling in pituitary tumor function, we examined these receptors in human prolactinomas. Immunofluorescent p185her2/neu was detected in almost all (seven of eight), and ErbB3 expression in a subset (four of eight) of tumors (seven adenomas and one carcinoma). Quantitative PCR also showed abundant ErbB3 mRNA in tumor specimens derived from a rarely encountered prolactin-cell carcinoma. Activation of p185c-neu/ErbB3 signaling with heregulin, the ErbB3 ligand, in rat lacto-somatotroph (GH4C1) tumor cells specifically induced prolactin (PRL) mRNA expression ∼5-fold and PRL secretion ∼4-fold, whereas growth hormone expression was unchanged. Heregulin (6 nmol/L) induced tyrosine phosphorylation and ErbB3 and p185c-neu heterodimerization, with subsequent activation of intracellular ERK and Akt. The Akt signal was specific to ErbB3 activation by heregulin, and was not observed in response to epidermal growth factor activation of epidermal growth factor receptor. Gefitinib, the tyrosine kinase inhibitor, suppressed heregulin-mediated p185c-neu/ErbB3 signaling to PRL. Heregulin induction of PRL was also abrogated by transfecting cells with short interfering RNA directed against ErbB3. Pharmacologic inhibition of heregulin-induced phosphoinositide-3-kinase/Akt (with LY294002) and ERK (with U0126) signaling, as well as short interfering RNA–mediated mitogen-activated protein kinase-1 down-regulation, showed ERK signaling as the primary transducer of heregulin signaling to PRL. These results show ErbB3 expression in human prolactinomas and a novel ErbB3-mediated mechanism for PRL regulation in experimental lactotroph tumors. Targeted inhibition of up-regulated p185c-neu/ErbB3 activity could be useful for the treatment of aggressive prolactinomas resistant to conventional therapy. [Cancer Res 2009;69(10):4209–16]