Termite ecology in a dry evergreen forest in Thailand in terms of stable (δ 13C and δ 15N) and radio (14C, 137Cs and 210Pb) isotopes

Stable (¹³C and ¹⁵N) and radio- (¹⁴C, ¹³⁷Cs and ²¹⁰Pb) isotopes were determined for termites that have been sampled from a dry evergreen forest in Thailand. A wood-feeding termite, Microcerotermes crassus, was separated from soil-feeders: Termes propinquus, Termes comis and Dicuspiditermes makhamensis by ¹³C and ¹⁵N values. The Termes group in Thailand had less diverse values in ¹³C and ¹⁵N than those in Australia, where the feeding habits of the Termes group are more diverse. Other soil-feeding termites produced similar ¹³C values, but a larger range in ¹⁵N values. ¹⁴C-percent modern carbon (pMC) values suggest that the soil-feeding termites used younger carbon than the wood-feeding termites, and this was consistent with the termites from Cameroon, central Africa. Values of ¹³C and ¹⁴C-pMC indicate that surface soil was used by a soil-feeding termite, D. makhamensis, in making the nest mounds, and deeper soil (10–30 cm) by a fungus-growing termite, Macrotermes carbonarius. ²¹⁰Pb and ¹³⁷Cs were scarcely incorporated into the termites, although ²¹⁴Pb was recovered from the workers. The results suggest that stable- and radioisotopes are useful in the study of detritivorous animals, organic matter decomposition and ecosystem engineering.Takuya Abe - deceased.     

Reaper-mediated inhibition of DIAP1-induced DTRAF1 degradation results in activation of JNK in Drosophila

Although Jun amino-terminal kinase (JNK) is known to mediate a physiological stress signal that leads to cell death, the exact role of the JNK pathway in the mechanisms underlying intrinsic cell death is largely unknown. Here we show through a genetic screen that a mutant of Drosophila melanogaster tumour-necrosis factor receptor-associated factor 1 (DTRAF1) is a dominant suppressor of Reaper-induced cell death. We show that Reaper modulates the JNK pathway through Drosophila inhibitor-of-apoptosis protein 1 (DIAP1), which negatively regulates DTRAF1 by proteasome-mediated degradation. Reduction of JNK signals rescues the Reaper-induced small eye phenotype, and overexpression of DTRAF1 activates the Drosophila ASK1 (apoptosis signal-regulating kinase 1; a mitogen-activated protein kinase kinase kinase) and JNK pathway, thereby inducing cell death. Overexpresson of DIAP1 facilitates degradation of DTRAF1 in a ubiquitin-dependent manner and simultaneously inhibits activation of JNK. Expression of Reaper leads to a loss of DIAP1 inhibition of DTRAF1-mediated JNK activation in Drosophila cells. Taken together, our results indicate that DIAP1 may modulate cell death by regulating JNK activation through a ubiquitin#150;proteasome pathway.     

Fluctuation of the zooplankton community in Lake Biwa during the 20th century: a paleolimnological analysis

Detailed zooplankton records from a 26-cm sediment core with a time resolution of approximately 3–10 years were obtained from Lake Biwa, Japan, to examine the historical variations in the zooplankton community during the 20th century. In the sediments, selected zooplankton remains have fluctuated over the years. Daphnia – large zooplankton herbivores – did not occur from 1900 to 1920, and formed a very minor component of the zooplankton community in the following 30 years, while Bosmina – small zooplankton herbivores – were common during this period. In the mid-1960s, however, when eutrophication was noticeable in this lake, Daphnia numbers increased dramatically and became the dominant zooplankton thereafter. In contrast, Difflugia brevicolla and D. biwae, two amoeboid protozoans that live in connection with the lake bottom environment, occurred abundantly until the late 1950s, but gradually decreased after the mid-1960s. In particular, D. biwae, a species peculiar to this lake, was not found in sediment dated after 1980, suggesting its extinction. These results indicate that the zooplankton community structure changed greatly in the 1960s, and suggest that the eutrophication occurring at this time altered the relative strength of top-down and bottom-up forces on the zooplankton community in Lake Biwa.     

Extraction of total RNA from leaves of Eucalyptus and other woody and herbaceous plants using sodium isoascorbate

Rapid extraction of total RNA from Eucalyptus leaves is difficult due to the high content of polyphenolics and polysaccharides. A rapid and simple method was developed by using an extraction buffer containing sodium isoascorbate at a concentration of 500 mM. This method consisted of one or two chloroform extractions, one acid guanidium-phenol-chloroform extraction, and isopropanol precipitation alone. The yields of the RNA fractions were 246-1750 micrograms/g fresh weight when leaves of Eucalyptus, five other woody plants, and four herbaceous plants were used as samples. The contamination of the RNA fractions by proteins and polysaccharides was very limited as judged spectrophotometrically. When the RNA fractions were subjected to agarose gel electrophoresis, intact rRNA bands were detected. The RNA fractions could be used for RT-PCR. These results indicate that our new method achieves a simple and rapid preparation of high-quality RNA from leaves of Eucalyptus and other plant species.     

Anthropometric measurements of the endoscopic eyebrow lift in the treatment of facial paralysis

Endoscopic eyebrow lift was performed on 51 patients presenting with eyebrow ptosis due to facial paralysis. The resulting anthropometric measurements of eyebrow position were analyzed statistically to evaluate the effectiveness of this method. When preoperative eyebrow differences between the paralyzed and nonparalyzed sides were measured, the average difference at midpoint was 4.4 mm, and at the highest point, 4.6 mm. When the same points were measured postoperatively, the average difference at midpoint was 2.4 mm, and at the highest point, 2.3 mm. The difference in eyebrow height between the paralyzed and nonparalyzed sides correlated positively with age, both preoperatively and postoperatively. However, differences between preoperative and postoperative eyebrow height (which reflects the effectiveness of endoscopic eyebrow lift) at the highest point did not correlate with age and at the midpoint displayed a slightly negative correlation with age. These results suggest that endoscopic eyebrow lift is effective among young patients whose eyebrow ptosis is minor and is relatively ineffective among elderly patients whose eyebrow ptosis is severe. The conventional method of juxta-brow excision is indicated for elderly patients, for whom the operative scar is almost inconspicuous.     

Clinical implications of thermal therapy in lifestyle-related diseases

Systemic thermal therapy, such as taking a warm-water bath and sauna, induces systemic vasodilation. It was found that repeated sauna therapy (60 degrees C for 15 min) improved hemodynamic parameters, clinical symptoms, cardiac function, and vascular endothelial function in patients with congestive heart failure. Vascular endothelial function is impaired in subjects with lifestyle-related diseases, such as hypertension, hyperlipidemia, diabetes mellitus, obesity, and smoking. Sauna therapy also improved endothelial dysfunction in these subjects, suggesting a preventive role for atherosclerosis. In animal experiments, sauna therapy increases mRNA and protein levels of endothelial nitric oxide synthase (eNOS) in aortas. In normal-weight patients with appetite loss, repeated sauna therapy increased plasma ghrelin concentrations and daily caloric intake and improved feeding behavior. In obese patients, the body weight and body fat significantly decreased after 2 weeks of sauna therapy without increase of plasma ghrelin concentrations. On the basis of these data, sauna therapy may be a promising therapy for patients with lifestyle-related diseases.     

Ser-130 of Natronobacterium pharaonis halorhodopsin is important for the chloride binding

Pharaonis halorhodopsin (phR) is an inward light-driven chloride ion pump from Natronobacterium pharaonis. In order to clarify the role of Ser-130(phR) residue which corresponds to Ser-115(shR) for salinarum hR on the anion-binding affinity, the wild-type and Ser-130 mutants substituted with Thr, Cys and Ala were expressed in E. coli cells and solubilized with 0.1% n-dodecyl beta-D-maltopyranoside The absorption maximum (lambda(max)) of the S130T mutant indicated a blue shift from that of the wild type in the absence and presence of chloride. For S130A, a large red shift (12 nm) in the absence of chloride was observed. The wild-type and all mutants showed the blue-shift of lambda(max) upon Cl(-) addition, from which the dissociation constants of Cl(-) were determined. The dissociation constants were 5, 89, 153 and 159 mM for the wild-type, S130A, S130T and S130C, respectively, at pH 7.0 and 25 degrees C. Circular dichroic spectra of the wild-type and the Ser-130 mutants exhibited an oligomerization. The present study revealed that the Ser-130 of N. pharaonis halorhodopsin is important for the chloride binding.     

Biosynthesis and action of neurosteroids in the cerebellar Purkinje neuron

The brain is considered to be a target site of peripheral steroid hormones. In contrast to this classical concept, new findings over the past decade have established that the brain itself also synthesizes steroids de novo from cholesterol through mechanisms at least partly independent of peripheral steroidogenic glands. Such steroids synthesized de novo in the brain, as well as other areas of the nervous system, are called neurosteroids. To understand neurosteroid actions in the brain, we need data on the specific synthesis in particular sites of the brain at particular times. Therefore, our studies for this exciting area of brain research have focused on the biosynthesis and action of neurosteroids in the identified neurosteroidogenic cells underlying important brain functions. We have demonstrated that the Purkinje cell, a typical cerebellar neuron, is a major site for neurosteroid formation in the brain. This is the first observation of neuronal neurosteroidogenesis in the brain. Subsequently, genomic and nongenomic actions of neurosteroids have become clear by a series of our studies using an excellent Purkinje cellular model. On the basis of these findings, we summarize the advances made in our understanding of biosynthesis and action of neurosteroids in the cerebellar Purkinje cell.