Terrigenous sediment-dominated reef platform infilling: an unexpected precursor to reef island formation and a test of the reef platform size–island age model in the Pacific

Low-lying coral reef islands are considered highly vulnerable to climate change, necessitating an improved understanding of when and why they form, and how the timing of formation varies within and among regions. Several testable models have been proposed that explain inter-regional variability as a function of sea-level history and, more recently, a reef platform size model has been proposed from the Maldives (central Indian Ocean) to explain intra-regional (intra-atoll) variability. Here we present chronostratigraphic data from Pipon Island, northern Great Barrier Reef (GBR), enabling us to test the applicability of existing regional island evolution models, and the platform size control hypothesis in a Pacific context. We show that reef platform infilling occurred rapidly (~4–5 mm yr⁻¹) under a “bucket-fill” type scenario. Unusually, this infilling was dominated by terrigenous sedimentation, with platform filling and subsequent reef flat formation complete by ~5000 calibrated years BP (cal BP). Reef flat exposure as sea levels slowly fell post highstand facilitated a shift towards intertidal and subaerial-dominated sedimentation. Our data suggest, however, a lag of ~1500 yr before island initiation (at ~3200 cal BP), i.e. later than that reported from smaller and more evolutionarily mature reef platforms in the region. Our data thus support: (1) the hypothesis that platform size acts to influence the timing of platform filling and subsequent island development at intra-regional scales; and (2) the hypothesis that the low wooded islands of the northern GBR conform to a model of island formation above an elevated reef flat under falling sea levels.

     

Methylated DNA/RNA in Body Fluids as Biomarkers for Lung Cancer

DNA/RNA methylation plays an important role in lung cancer initiation and progression. Liquid biopsy makes use of cells, nucleotides and proteins released from tumor cells into body fluids to help with cancer diagnosis and prognosis. Methylation of circulating tumor DNA (ctDNA) has gained increasing attention as biomarkers for lung cancer. Here we briefly introduce the biological basis and detection method of ctDNA methylation, and review various applications of methylated DNA in body fluids in lung cancer screening, diagnosis, prognosis, monitoring and treatment prediction. We also discuss the emerging role of RNA methylation as biomarkers for cancer.     

Biodeterioration of Mayan buildings at uxmal and tulum,Mexico

Uxmal and Tulum are two important Mayan sites in the Yucatan peninsula. The buildings are mainly composed of limestone and grey/black discoloration is seen on exposed walls and copious greenish biofilms on inner walls. The principal microorganisms detected on interior walls at both Uxmal and Tulum were cyanobacteria; heterotrophic bacteria and filamentous fungi were also present. A dark‐pigmented mitosporic fungus and Bacillus cereus, both isolated from Uxmal, were shown to be acidogenic in laboratory cultures. Cyanobacteria belonging to rock‐degrading genera Synechocystis and Gloeocapsa were identified at both sites. Surface analysis previously showed that calcium ions were present in the biofilms on buildings at Uxmal and Tulum, suggesting the deposition of biosolubilized stone. Apart from their potential to degrade the substrate, the coccoid cyanobacteria supply organic nutrients for bacteria and fungi, which can produce organic acids, further increasing stone degradation.     

Guidelines for heart transplantation

Based on the changes in the field of heart transplantation and the treatment and prognosis of patients with heart failure, these updated guidelines were composed by a committee under the supervision of both the Netherlands Society of Cardiology and the Netherlands Association for Cardiothoracic surgery (NVVC and NVT). The indication for heart transplantation is defined as: ‘End-stage heart disease not remediable by more conservative measures’. Contraindications are: irreversible pulmonary hypertension/elevated pulmonary vascular resistance; active systemic infection; active malignancy or history of malignancy with probability of recurrence; inability to comply with complex medical regimen; severe peripheral or cerebrovascular disease and irreversible dysfunction of another organ, including diseases that may limit prognosis after heart transplantation. Considering the difficulties in defining end-stage heart failure, estimating prognosis in the individual patient and the continuing evolution of available therapies, the present criteria are broadly defined. The final acceptance is done by the transplant team which has extensive knowledge of the treatment of patients with advanced heart failure on the one hand and thorough experience with heart transplantation and mechanical circulatory support on the other hand. (Neth Heart J 2008;16:79-87.)     

The first record of Sirenia (Mammalia) from the early Oligocene of the Paratethys

Abstract

Sirenians have been extensively recorded from the Mediterranean and west European localities but there are only few finds to the east of it, from the area covered by the Paratethys. For the early Oligocene, to our knowledge, there are no published records of sirenians from inner seas of the Old World. Here we report a specimen of Dugongidae indet., consisting of two partial vertebrae and 12 fragments of ribs, collected in a manganese ore mine in Ukraine and dated as the earliest Oligocene (33–32 Ma). The specimens, as preserved, did not differ in morphology and size from ‘Halitherium schinzii’ and therefore can belong to Kaupitherium, at present the single early Oligocene genus recorded from Europe. However, its vertebral and rib anatomy is not specific for Kaupitherium, so we identify it only by family level. The marks of scavenging on a rib possibly are due to gastropod or bivalve mollusks. The sea, as suggested from biotic data, had a temperate or subtropical climate, relatively cold waters and high diversity of pelagic and deep-water habitats. Thus, the onset of the Oligocene was a period when sirenians could enter temperate inner Eurasian waters, a marginal area in their worldwide dispersal.     

The role of free calmodulin in the regulation of calcium-pump activity in erythrocytes

The activity of Ca-pump in inside-out oriented vesicles obtained from erythrocyte membranes after their 30 min treatment with EGTA at 20 degrees C (membranes A) and 37 degrees C (membranes B) was investigated. It was shown that in membranes A placed into an incubation medium containing 0.1 mM EGTA (pH 7.4) the overall effect of exogenous calmodulin is due to the increase in the maximal activity of the enzyme, its affinity for Ca2+ being unaffected thereby. In membranes B placed into the same medium (pH 6.75) the activation of the Ca-pump by calmodulin is due to the increased affinity for Ca2+ at a constant maximal activity of the enzyme. The dependencies of the value of the calmodulin-stimulated component of membranes A and the Ca2+-binding capacity of calmodulin measured by the intensity of N-phenyl-1-naphthylamine fluorescence on the concentration of free Ca2+ are coincident. In the case of membranes B, the stimulation of Ca-pump by calmodulin occurs at much lower Ca2+ concentrations than the Ca2+ binding-induced conformational shifts in calmodulin. The experimental results suggest that the affinity of the Ca-pump for Ca2+ may affect calmodulin existing in a Ca2+-independent state. The hydrophobic interactions between the Ca-calmodulin complex and the Ca-ATPase molecule are apparently essential for the regulation of the maximal enzyme activity.     

From Problem Taxa to Problem Solver: A New Miocene Family,Tranatocetidae, Brings Perspective on Baleen Whale Evolution

Miocene baleen whales were highly diverse and included tens of genera. However, their taxonomy and phylogeny, as well as relationships with living whales, are still a subject of controversy. Here, “Mesocetus” argillarius, a poorly known specimen from Denmark, is redescribed with a focus on the cranial anatomy. It was found to represent not only a new genus, Tranatocetus gen. nov., but also a new family; Tranatocetidae. The whales of this family have the rostral bones either overriding or dividing the frontals; the rostral bones are contacting the parietals and nasals dividing the maxillae on the vertex; the occipital shield is dorsoventrally bent. The tympanic bulla is particularly characteristic of this family featuring a short, narrow anterior portion with a rounded or squared anterior end and a wider and higher posterior portion that is swollen in the posteroventral area. A phylogenetic analysis including 51 taxa supports a monophyletic group comprising most Neogene and modern whales, with Tranatocetidae being possibly closer related to Balaenopteridae (rorquals) than to Cetotheriidae. Tranatocetidae exhibit a charahteristic bulla shape. In fact, all Neogene and modern mysticete families examined have a unique shape of the tympanic bulla that is diagnostic at family-level. Inclusion of problematic taxa like Tranatocetus argillarius in phylogenies brings new understanding of the distribution and diagnostic value of character traits. This underlines the need for re-examination of earlier described specimens in the light of the wealth of new information published in later years.     

Genetic Admixture in the Culturally Unique Peranakan Chinese Population in Southeast Asia

The Peranakan Chinese are culturally unique descendants of immigrants from China who settled in the Malay Archipelago ∼300–500 years ago. Today, among large communities in Southeast Asia, the Peranakans have preserved Chinese traditions with strong influence from the local indigenous Malays. Yet, whether or to what extent genetic admixture co-occurred with the cultural mixture has been a topic of ongoing debate. We performed whole-genome sequencing (WGS) on 177 Singapore (SG) Peranakans and analyzed the data jointly with WGS data of Asian and European populations. We estimated that Peranakan Chinese inherited ∼5.62% (95% confidence interval [CI]: 4.76–6.49%) Malay ancestry, much higher than that in SG Chinese (1.08%, 0.65–1.51%), southern Chinese (0.86%, 0.50–1.23%), and northern Chinese (0.25%, 0.18–0.32%). A sex-biased admixture history, in which the Malay ancestry was contributed primarily by females, was supported by X chromosomal variants, and mitochondrial (MT) and Y haplogroups. Finally, we identified an ancient admixture event shared by Peranakan Chinese and SG Chinese ∼1,612 (95% CI: 1,345–1,923) years ago, coinciding with the settlement history of Han Chinese in southern China, apart from the recent admixture event with Malays unique to Peranakan Chinese ∼190 (159–213) years ago. These findings greatly advance our understanding of the dispersal history of Chinese and their interaction with indigenous populations in Southeast Asia.