Decline in skeletal growth of the coral Porites?lutea from the Andaman Sea, South Thailand between 1984 and 2005

Of the few studies that have examined in situ coral growth responses to recent climate change, none have done so in equatorial waters subject to relatively high sea temperatures (annual mean >27°C). This study compared the growth rate of Porites lutea from eight sites at Phuket, South Thailand between two time periods (December 1984–November 1986 and December 2003–November 2005). There was a significant decrease in coral calcification (23.5%) and linear extension rates (19.4–23.4%) between the two sampling periods at a number of sites, while skeletal bulk density remained unchanged. Over the last 46 years, sea temperatures (SST) in the area have risen at a rate of 0.161°C per decade (current seasonal temperature range 28–30°C) and regression analysis of coral growth data is consistent with a link between rising temperature and reduced linear extension in the order of 46–56% for every 1°C rise in SST. The apparent sensitivity of linear extension in P. lutea to increased SST suggests that corals in this part of the Andaman Sea may already be subjected to temperatures beyond their thermal optimum for skeletal growth. Communicated by Environment Editor Prof. Rob van Woesik     

Regional decline in growth rates of massive Porites corals in Southeast Asia

This study reports the first well‐replicated analysis of continuous coral growth records from warmer water reefs (mean annual sea surface temperatures (SST) >28.5 °C) around the Thai–Malay Peninsula in Southeast Asia. Based on analyses of 70 colonies sampled from 15 reefs within six locations, region‐wide declines in coral calcification rate (ca. 18.6%), linear extension rate (ca. 15.4%) and skeletal bulk density (ca. 3.9%) were observed over a 31‐year period from 1980 to 2010. Decreases in calcification and linear extension rates were observed at five of the six locations and ranged from ca. 17.2–21.6% and ca. 11.4–19.6%, respectively, whereas decline in skeletal bulk density was a consequence of significant reductions at only two locations (ca. 6.9% and 10.7%). A significant link between region‐wide growth rates and average annual SST was found, and Porites spp. demonstrated a high thermal threshold of ca. 29.4 °C before calcification rates declined. Responses at individual locations within the region were more variable with links between SST and calcification rates being significant at only four locations. Rates of sea temperature warming at locations in the Andaman Sea (Indian Ocean) (ca. 1.3 °C per decade) were almost twice those in the South China Sea (Pacific Ocean) (ca. 0.7 °C per decade), but this was not reflected in the magnitude of calcification declines at corresponding locations. Considering that massive Porites spp. are major reef builders around Southeast Asia, this region‐wide growth decline is a cause for concern for future reef accretion rates and resilience. However, this study suggests that the future rates and patterns of change within the region are unlikely to be uniform or dependent solely on the rates of change in the thermal environment.     

Continuous cultivation of human hamstring tenocytes on microcarriers in a spinner flask bioreactor system

Tendon healing is a time consuming process leading to the formation of a functionally altered reparative tissue. Tissue engineering‐based tendon reconstruction is attracting more and more interest. The aim of this study was to establish tenocyte expansion on microcarriers in continuous bioreactor cultures and to study tenocyte behavior during this new approach. Human hamstring tendon‐derived tenocytes were expanded in monolayer culture before being seeded at two different seeding densities (2.00 and 4.00 × 10⁶ cells/1000 cm² surface) on Cytodex? type 3 microcarriers. Tenocytes' vitality, growth kinetics and glucose/lactic acid metabolism were determined dependent on the seeding densities and stirring velocities (20 or 40 rpm) in a spinner flask bioreactor over a period of 2 weeks. Gene expression profiles of tendon extracellular matrix (ECM) markers (type I/III collagen, decorin, cartilage oligomeric protein [COMP], aggrecan) and the tendon marker scleraxis were analyzed using real time detection polymerase chain reaction (RTD‐PCR). Type I collagen and decorin deposition was demonstrated applying immunolabeling. Tenocytes adhered on the carriers, remained vital, proliferated and revealed an increasing glucose consumption and lactic acid formation under all culture conditions. “Bead‐to‐bead” transfer of cells from one microcarrier to another, a prerequisite for continuous tenocyte expansion, was demonstrated by scanning electron microscopy. Type I and type III collagen gene expression was mainly unaffected, whereas aggrecan and partly also decorin and COMP expression was significantly downregulated compared to monolayer cultures. Scleraxis gene expression revealed no significant regulation on the carriers. In conclusion, tenocytes could be successfully expanded on microcarriers. Therefore, bioreactors are promising tools for continuous tenocyte expansion. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 30:142–151, 2014     

Glutathione and adaptive immune responses against Mycobacterium tuberculosis infection in healthy and HIV infected individuals

Glutathione (GSH), a tripeptide antioxidant, is essential for cellular homeostasis and plays a vital role in diverse cellular functions. Individuals who are infected with Human immuno deficiency virus (HIV) are known to be susceptible to Mycobacterium tuberculosis (M. tb) infection. We report that by enhancing GSH levels, T-cells are able to inhibit the growth of M. tb inside macrophages. In addition, those GSH-replenished T cell cultures produced increased levels of Interleukin-2 (IL-2), Interleukin-12 (IL-12), and Interferon-gamma (IFN-γ), cytokines, which are known to be crucial for the control of intracellular pathogens. Our study reveals that T lymphocytes that are derived from HIV infected individuals are deficient in GSH, and that this deficiency correlates with decreased levels of Th1 cytokines and enhanced growth of M. tb inside human macrophages.     

Sub-annual fluorescence measurements of coral skeleton: relationship between skeletal luminescence and terrestrial humic-like substances

Coral Reefs - Some massive coral core slices reveal luminescent bands under ultraviolet light, which have been attributed to terrestrial humic acids in the skeleton. Coral luminescence has...     

An alternative splicing variant of mineralocorticoid receptor discovered in preeclampsia tissues and its effect on endothelial dysfunction

The pathophysiology of preeclampsia (PE) remains unclear.PE spiral artery remodeling dysfunction and PE offspring cardiovascular future development has been a worldwide concern.We collected placental and umbilical artery samples from normotensive and PE pregnancies.Mineralocorticoid receptor (MR) and its alternative splicing variant (ASV) expression and their biological effects on PE were examined.An MR ASV was found to be highly expressed in all PE samples and slightly expressed in about half of the normotensive samples (umbilical artery,～57.58%;placenta,～36.84%).The MR ASV expression was positively associated with blood pressure in both groups.The MR ASV protein changed the aldosterone-induced expression pattern of MR target genes related to ion exchanges and cell signaling pathways.The MR ASV can also impair the proliferation,migration,and tube formation ability of endothelial cells.These findings indicate that MR ASV in PE placenta plays a pathogenic role in PE pathophysiology,especially in endothelial dysfunction,and the existence of the MR ASV in PE umbilical artery provides a new direction in the study of PE offspring with increased risk of cardiovascular diseases.