Chemical identification and ethological function of soldier-specific secretion in Japanese subterranean termite Reticulitermes speratus (Rhinotermitidae)

We identified the soldier-specific compounds in the Japanese subterranean termite, Reticulitermes speratus, to clarify their ethological roles. Silica gel column chromatography separated one major soldier-specific compound in the hexane fraction accounting for 70-80% of the total amount of the fraction, while cuticular hydrocarbons constituted the rest. We identified the compound as β-selinene by gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) spectroscopy. Comparative GC analyses of the major exocrine glands detected the compound in the soldier's frontal gland. Both soldiers and workers made aggregation to the hexane fraction, as well as to the crushed heads and head extract of the soldiers. They did not aggregate to cuticular hydrocarbons, making it likely that β-selinene was the aggregation pheromone in this species. The opportunistic predator of this termite, Lasius japonicus, was also attracted to the compounds. The ant workers, therefore, would use the termite aggregation pheromone as a kairomone for hunting them.     

Independent external validation of nomograms for predicting risk of low-trauma fracture and hip fracture

Background

A set of nomograms based on the Dubbo Osteoporosis Epidemiology Study predicts the five- and ten-year absolute risk of fracture using age, bone mineral density and history of falls and low-trauma fracture. We assessed the discrimination and calibration of these nomograms among participants in the Canadian Multicentre Osteoporosis Study.

Methods

We included participants aged 55–95 years for whom bone mineral density measurement data and at least one year of follow-up data were available. Self-reported incident fractures were identified by yearly postal questionnaire or interview (years 3, 5 and 10). We included low-trauma fractures before year 10, except those of the skull, face, hands, ankles and feet. We used a Cox proportional hazards model.

Results

Among 4152 women, there were 583 fractures, with a mean follow-up time of 8.6 years. Among 1606 men, there were 116 fractures, with a mean follow-up time of 8.3 years. Increasing age, lower bone mineral density, prior fracture and prior falls were associated with increased risk of fracture. For low-trauma fractures, the concordance between predicted risk and fracture events (Harrell C) was 0.69 among women and 0.70 among men. For hip fractures, the concordance was 0.80 among women and 0.85 among men. The observed fracture risk was similar to the predicted risk in all quintiles of risk except the highest quintile of women, where it was lower. The net reclassification index (19.2%, 95% confidence interval [CI] 6.3% to 32.2%), favours the Dubbo nomogram over the current Canadian guidelines for men.

Interpretation

The published nomograms provide good fracture-risk discrimination in a representative sample of the Canadian population.Current recommendations for the treatment of osteoporosis are in transition. The T-score-based definition of osteoporosis and osteopenia by the expert committee of the World Health Organization on bone mineral density has been used in many guidelines to set intervention thresholds for treatment. However, studies have consistently reported that the highest number of fractures in a given population occurs in those with osteopenic or normal bone mineral density.^1,2 In fact, the National Osteoporosis Foundation has singled out people with osteopenic bone mineral density as a population in which assessment for fracture risk is merited.³Nevertheless, appropriate prevention and treatment strategies for such people are uncertain.⁴ Recent developments include the assessment of absolute fracture risk based on bone mineral density and other risk factors. Current Canadian methodology determines categorical risk based on age, sex, T-score, fracture history and glucocorticoid use.⁵ These criteria were derived from Swedish data, but have been assessed and validated in a cohort of Manitoba women.⁶ Newer nomograms based on the Australian cohort of the Dubbo Osteoporosis Epidemiology Study⁷ are now available for the calculation of low-trauma hip fracture⁸ and any fracture.⁹ These nomograms provide continuous estimates for five- and 10-year absolute fracture risk in both men and women (available at http://fractureriskcalculator.com). The use of factors in addition to bone mineral density may provide a better assessment of fracture risk for people who are near the T-score thresholds and facilitate decisions regarding therapeutic intervention.A key step in the development of any prediction model is the assessment of its validity.¹⁰ The aim of our study was to assess the performance of the Australian-derived nomogram among community-dwelling Canadians aged 55–95 years old. The first part of this assessment was a comparison of the nomogram model using the same variables, but using data from a Canadian population — participants in the Canadian Multicentre Osteoporosis Study (www.camos.org). The second part involved computing the calibration and discrimination of the nomogram in a Canadian cohort. The final part was comparison of the new assessments with the existing Canadian risk classification system.     

Gill remodeling in crucian carp during sustained exercise and the effect on subsequent swimming performance

Gill remodeling can be extensive in crucian carp, where up to a 7.5-fold increase in gill surface area has been observed during exposure to hypoxia through a reduction in the interlamellar cell mass (ILCM) and increased lamellar protrusion that has been hypothesized to be signaled by the need to maximize oxygen uptake under a given condition. Sustained aerobic exercise may have the greatest influence on oxygen demand in fish; however, its effect on gill remodeling in crucian carp has not been investigated. The specific objectives of this study were to determine (i) whether sustained aerobic exercise induces gill remodeling in the crucian carp, (ii) whether gill remodeling following sustained exercise affects the maximum critical swimming speed (U(crit)) and maximal oxygen consumption rate ([Formula: see text]), and (iii) whether gill remodeling following sustained exercise is associated with trade-offs related to ionoregulation. We measured [Formula: see text] in crucian carp at each step during an initial U(crit) test (U(crit1)), forced them to swim at 70% of U(crit) for 40 h, and then conducted a second U(crit) test (U(crit2)). From rest to U(crit1) (7-8 h), we observed a significant increase in protruding lamella height and area of the gills and a reduction in ILCM height and volume, likely associated with partial shedding of the ILCM, indicating that gill remodeling during exercise is rapid. Further changes were observed between U(crit1) and U(crit2), with statistically significant increases in protruding lamellar height, basal length and area, and a statistically significant reduction in protruding lamellar thickness and ILCM height and volume. Interestingly, there was no significant difference between U(crit1) and U(crit2) values, nor in maximal [Formula: see text] measured at U(crit1) and U(crit2). Furthermore, there was no significant difference in plasma osmolarity, [Na(+)], or [Cl(-)] in fish at rest, following U(crit1) or U(crit2). Thus, while these data support the hypothesis that the need to maximize oxygen uptake is an important signal for gill remodeling, which can occur quite rapidly (within 7 h at 15°C), the physiological implications of remodeling during exercise are less clear.     

One step forward: the use of transgenic zebrafish tumor model in drug screens

The zebrafish (Danio rerio) has been an experimental model in the developmental biology and toxicology since the 1950s. In recent years, with the aid of transgenic technology, it has also gained an increasing popularity to model human diseases, including various cancers. As a feasible vertebrate model for large-scale chemical screens, the zebrafish has also given us a new option for the search of potential anticancer drugs. It is hopeful that in the near future with automation and analytical tools, drug development processes will be significantly shortened for quick and effective identification of candidate drugs.     

First report of the benthic dinoflagellate,Gambierdiscus belizeanus (Gonyaulacales: Dinophyceae) for the east coast of Sabah,Malaysian Borneo

Species of the genus Gambierdiscus Adachi & Fukuyo, in particular G. toxicus Adachi & Fukuyo are known producers of neurotoxins associated with ciguatera fish poisoning (CFP). In this study live samples were collected from seaweed beds of the east coast of Sabah, Malaysian Borneo and a strain of Gambierdiscus was isolated and cultured. Examination of the thecal fine morphology was undertaken using light, epifluorescence, and scanning electron microscopy. Observed morphological features and their associated morphometric information enabled identification to Gambierdiscus belizeanus Faust. This represents the first report for the occurrence of G. belizeanus in the Asia Pacific region.     

Brain-derived neurotrophic factor from microglia: a molecular substrate for neuropathic pain

One of the most significant advances in pain research is the realization that neurons are not the only cell type involved in the etiology of chronic pain. This realization has caused a radical shift from the previous dogma that neuronal dysfunction alone accounts for pain pathologies to the current framework of thinking that takes into account all cell types within the central nervous system (CNS). This shift in thinking stems from growing evidence that glia can modulate the function and directly shape the cellular architecture of nociceptive networks in the CNS. Microglia, in particular, are increasingly recognized as active principal players that respond to changes in physiological homeostasis by extending their processes toward the site of neural damage, and by releasing specific factors that have profound consequences on neuronal function and that contribute to CNS pathologies caused by disease or injury. A key molecule that modulates microglia activity is ATP, an endogenous ligand of the P2 receptor family. Microglia expresses several P2 receptor subtypes, and of these the P2X4 receptor subtype has emerged as a core microglia-neuron signaling pathway: activation of this receptor drives the release of brain-derived neurotrophic factor (BDNF), a cellular substrate that causes disinhibition of pain-transmitting spinal lamina I neurons. Converging evidence points to BDNF from spinal microglia as being a critical microglia-neuron signaling molecule that gates aberrant nociceptive processing in the spinal cord. The present review highlights recent advances in our understanding of P2X4 receptor-mediated signaling and regulation of BDNF in microglia, as well as the implications for microglia-neuron interactions in the pathobiology of neuropathic pain.     

Cadmium-induced oxidative stress and apoptotic changes in the testis of freshwater crab, Sinopotamon henanense

Cadmium (Cd), one of the most toxic environmental and industrial pollutants, is known to exert gonadotoxic and spermiotoxic effects. In the present study, we examined the toxic effect of Cd on the testis of freshwater crab, Sinopotamon henanense. Crabs were exposed to different Cd concentrations (from 0 to 116.00 mg·L(-1)) for 7 d. Oxidative stress and apoptotic changes in the testes were detected. The activities of SOD, GPx and CAT initially increased and subsequently decreased with increasing Cd concentrations, which was accompanied with the increase in malondialdehyde (MDA) and H(2)O(2) content in a concentration-dependent manner. Typical morphological characteristic and physiological changes of apoptosis were observed using a variety of methods (HE staining, AO/EB double fluorescent staining, Transmission Electron Microscope observation and DNA fragmentation analysis), and the activities of caspase-3 and caspase-9 were increased in a concentration-dependent manner after Cd exposure. These results led to the conclusion that Cd could induced oxidative damage as well as apoptosis in the testis, and the apoptotic processes may be mediated via mitochondria-dependent apoptosis pathway by regulating the activities of caspase-3 and caspase-9.     

High-Yield Expression and Purification of Human Interferon α-1 in Pichia pastoris

For several years, interferon α-1, also known as interferon α-D, has been studied for treatment of various viral diseases, such as hepatic fibrosis caused by hepatitis B, herpes simplex virus keratitis, and bovine respiratory diseases in calves. Currently, recombinant human interferon α-D (rHuIFNαD) is expressed intracellularly in Escherichia coli or secreted by Bacillus subtilis and Saccharomyces cerevisiae. In this report, we describe the process of obtaining a relatively high-yield secretion of biologically active recombinant rHuIFNαD using the Pichia pastoris system. The process produced as high as 0.7 mg of purified protein per 20 ml of shake culture of rHuIFNαD with better bioactivity than the commercially available rHuIFNαD molecule produced in E. coli.