Radiolarian biostratigraphy of Peninsular Malaysia and implications for regional palaeotectonics and palaeogeography

Peninsular Malaysia consists of three terranes, a western Gondwanan affinity terrane (Sibumasu), an eastern Cathaysian affinity terrane (Indochina/East Malaya) and an accretionary complex terrane (the Palaeo-Tethyan Bentong-Raub suture zone) which contains fault-bounded blocks and clasts of radiolarian-bearing chert and argillite. ... The representation of the Palaeo-Tethyan suture zone of Peninsular Malaysia as a narrow zone (13 - 18 km wide) is not favoured in this study. The Gondwanan affinity Sibumasu terrane is narrower than presently defined and includes only passive margin continental sequences. All radiolarian-bearing chert and argillite, belts of mélange and imbricate thrust slices of marine sedimentary rocks characteristic of accretionary complexes are not part of the Sibumasu or Indochina/East Malaya terranes, but are of Palaeo-Tethyan origin, and form a distinct accretionary complex terrane which has been thrust westwards over the eastwards-dipping Sibumasu terrane. The Bentong-Raub suture zone of Peninsular Malaysia, the Uttaradit-Nan/Sra Kaeo suture zone of Thailand and the Changning-Menglian suture zone of South China have yielded radiolarian faunas of similar biostratigraphic ages, ranging from Upper Devonian (Famennian), through Middle Triassic (Ladinian). These ages suggest that the Palaeo-Tethys ocean existed between the Sibumasu and Indochina terranes from at least Late Devonian through to Middle Triassic (Ladinian) time. Results of this thesis support tectonic models that propose Late Silurian - Early Devonian rifting of continental fragments from the Gondwanan margin, Devonian opening of the Palaeo-Tethys, and subsequent closure of the ocean in Peninsular Malaysia and Southeast Asia during the Late Triassic

Glycemic, Gastrointestinal, Hormonal and Appetitive Responses to Pearl Millet or Oats Porridge Breakfasts: a Randomized, Crossover Trial in Healthy Humans

Whole grain cereal breakfast consumption has been associated with beneficial effects on glucose and insulin metabolism as well as satiety. Pearl millet is a popular ancient grain variety that can be grown in hot, dry regions. However, little is known about its health effects. This study investigated the effect of a pearl millet porridge (PMP) compared with a well-known Scottish oats porridge (SOP) on glycaemic, gastrointestinal, hormonal and appetitive responses. In a randomized, two way crossover trial, 26 healthy participants consumed two iso-energetic/volumetric PMP or SOP breakfast meals, served with a drink of water. Blood samples for glucose, insulin, GLP-1, GIP and PYY, gastric volumes and appetite ratings were collected for two hours postprandially, followed by an ad libitum meal and food intake records for the remainder of the day. The incremental area under the curve (iAUC2h) for blood glucose was not significantly different between the porridges (p ˃ 0.05). The iAUC2h gastric volume was larger for PMP compared with SOP (p = 0.045). The iAUC2h GIP concentration was significantly lower for PMP compared with SOP (p = 0.001). Other hormones and appetite responses were similar between meals. In conclusion, this study reports, for the first time, data on glycaemic and physiological responses to a pearl millet breakfast, showing that this ancient grain could represent a sustainable, alternative, with health-promoting characteristics comparable to oats. GIP is an incretin hormone linked to triacylglycerol absorption in adipose tissue, therefore the lower GIP response for PMP may be an added health benefit

Centromere localization and function of Mis18 requires Yippee-like domain-mediated oligomerization.

Mis18 is a key regulator responsible for the centromere localization of the CENP-A chaperone Scm3 in Schizosaccharomyces pombe and HJURP in humans, which establishes CENP-A chromatin that defines centromeres. The molecular and structural determinants of Mis18 centromere targeting remain elusive. Here, by combining structural, biochemical, and yeast genetic studies, we show that the oligomerization of S. pombe Mis18, mediated via its conserved N-terminal Yippee-like domain, is crucial for its centromere localization and function. The crystal structure of the N-terminal Yippee-like domain reveals a fold containing a cradle-shaped pocket that is implicated in protein/nucleic acid binding, which we show is required for Mis18 function. While the N-terminal Yippee-like domain forms a homodimer in vitro and in vivo, full-length Mis18, including the C-terminal α-helical domain, forms a homotetramer in vitro We also show that the Yippee-like domains of human Mis18α/Mis18β interact to form a heterodimer, implying a conserved structural theme for Mis18 regulation.Wellcome Trust Career Development Grant095822 Principal Research Fellowship095021065061 Wellcome Trust Centre Core Grant092076091020 Wellcome Trust‐University of Edinburgh Institutional Strategic Support Fund EpiGeneSys Network of ExcellenceHEALTH‐F4‐2010‐257082 EC FP7 Marie Curie International Incoming FellowshipPIIF‐GA‐2010‐275280 EMBO Long Term FellowshipALTF 1491‐2010 Wellcome Trus

Radiolarian Biostratigraphy of Peninsular Malaysia and Implications for Regional Palaeotectonics and Palaeogeography

1,289 samples of chert and siliceous argillite from 78 localities in the Bentong-Raub suture zone (sensu stricto), the Semanggol Formation and other localities in Peninsular Malaysia have produced 97 species of Radiolaria representing 32 genera. Data from 12 localities in fault-bounded blocks of siliceous sedimentary rocks from the Bentong-Raub suture zone indicate Late Devonian (Famennian), Early Carboniferous (Tournaisian and Viséan), and Early Permian (Wolfcampian and Leonardian); these ages represent 8 radiolarian zones. In stratigraphic order these are the Holoeciscus 2-3, Albaillella deflandrei, A. cartalla, Pseudoalbaillella u-forma m. II, Ps. lomentaria, Ps. scalprata m. rhombothoracata, Albaillella sinuata and Pseudoalbaillella longtanensis zones. The "Lower Chert Member" of the Semanggol Formation of northwest Peninsular Malaysia produced latest Early Permian (upper Leonardian), Late Permian (Guadalupian) and Middle Triassic (Anisian and Ladinian) radiolarian assemblages representative of the ?Pseudoalbaillella longtanensis, Follicucullus porrectus, N. ornithoformis, Triassocampe coronata and T. deweveri zones. Two new species of the Late Permian genus Follicucullus ORMISTON & BABCOCK, F. crenulatus n. sp. and F. elongatus n. sp. are described from rocks previously assigned to the Lower Chert Member of the Semanggol Formation of northwest Peninsular Malaysia. The Late Permian Follicucullus japonicus Zone of ISHIGA (1991) is renamed the F. porrectus Zone. The age-spectrum of radiolarians recovered from the Bentong-Raub suture zone (sensu stricto) suggests that an ocean existed between the Sibumasu and Indochina/East Malaya terranes from at least Late Devonian to latest Early Permian time. The presence of latest Early Permian, Late Permian and Middle Triassic (Anisian and lower Ladinian) radiolarians from the "Lower Chert Member" of the Semanggol Formation, and ?Early Carboniferous radiolarians from tuffaceous chert near Kuala Kangsar in the west of the Peninsula, suggests that the accretionary complex of the Palaeo-Tethyan Bentong-Raub suture zone, may extend farther west than previously thought. The "Lower Chert Member" may not be part of the Semanggol Formation, but may be part of the underlying Palaeo-Tethyan accretionary complex. The presence of Late Permian radiolarian-bearing, ribbon-bedded chert from a single locality near Jengka, in the Central Belt, suggests that the Palaeo-Tethyan accretionary complex may also extend east beneath the Triassic Semantan Formation of the Central Belt. Representation of the Palaeo-Tethyan suture zone of Peninsular Malaysia as a narrow zone (13-18 km wide) is not favoured. The Gondwanan-affinity Sibumasu terrane is narrower than presently defined and includes only passive margin continental sequences. All radiolarian-bearing chert and argillite, belts of mélange and imbricate thrust slices of marine sedimentary rocks characteristic of accretionary complexes are not part of the Sibumasu or Indochina/East Malaya terranes, but are of Palaeo-Tethyan origin, forming a distinct accretionary complex terrane thrust westwards over the eastwards-dipping Sibumasu terrane. The Bentong-Raub suture zone of Peninsular Malaysia, the Uttaradit-Nan/Sra Kaeo suture zone of Thailand and the Changning-Menglian suture zone of South China have produced radiolarian faunas of similar biostratigraphic ages, ranging from Late Devonian (Famennian) to Middle Triassic (Ladinian). These ages suggest that Palaeo-Tethys existed between the Sibumasu and Indochina terranes from at least the Late Devonian, persisting through to Middle Triassic (Ladinian) times. © 2002 E. Schweizerbart'sche Verlagsbuchhandlung

A structural view of evolutionary divergence

Two directed evolution experiments on p-nitrobenzyl esterase yielded one enzyme with a 100-fold increased activity in aqueous-organic solvents and another with a 17°C increase in thermostability. Structures of the wild type and its organophilic and thermophilic counterparts are presented at resolutions of 1.5 Å, 1.6 Å, and 2.0 Å, respectively. These structures identify groups of interacting mutations and demonstrate how directed evolution can traverse complex fitness landscapes. Early-generation mutations stabilize flexible loops not visible in the wild-type structure and set the stage for further beneficial mutations in later generations. The mutations exert their influence on the esterase structure over large distances, in a manner that would be difficult to predict. The loops with the largest structural changes generally are not the sites of mutations. Similarly, none of the seven amino acid substitutions in the organophile are in the active site, even though the enzyme experiences significant changes in the organization of this site. In addition to reduction of surface loop flexibility, thermostability in the evolved esterase results from altered core packing, helix stabilization, and the acquisition of surface salt bridges, in agreement with other comparative studies of mesophilic and thermophilic enzymes. Crystallographic analysis of the wild type and its evolved counterparts reveals networks of mutations that collectively reorganize the active site. Interestingly, the changes that led to diversity within the α/β hydrolase enzyme family and the reorganization seen in this study result from main-chain movements

Lower and Middle Devonian radiolarian biozonation of the Gamilaroi Terrane New England Orogen, eastern Australia

Seven distinctive radiolarian assemblages defined from the Gamilaroi terrane of eastern Australia form the basis of an uppermost Lower to Middle Devonian radiolarian biostratigraphy. In ascending order these are the: Stigmosphaerostylus horrida, Helenifore laticlavium, Circulaforma admissarius, Helenifore pilosidiscus n. sp., Protoholoeciscus hindea, Ceratoikiscum regalinodus, and Trilonche minax assemblages. Gamilaroi terrane sedimentation occurred during the interval Early (Pragian) to Late (Frasnian) Devonian in a volcanic island arc environment in which radiolarians were abundant but sedimentary facies were locally variable. Radiolarian assemblages can be used for terrane-wide correlation. Although assemblages are dominated by spumellarians they also include more distinctive ceratoikiscid forms. Two new ceratoikiscid taxa: Circulaforma davidi n. sp. and Helenifore pilosidiscus n. sp are described