Molecular cloning of haploid germ cell-specific tektin cDNA and analysis of the protein in mouse testis.

Tektins are a class of proteins that form filamentous polymers in the walls of ciliary and flagellar microtubules. We report here the molecular cloning of a new member of the tektin family, tektin-t, identified from a mouse haploid germ cell-specific cDNA library. Tektin-t mRNA encodes a protein of 430 deduced amino acids possessing RSNVELCRD, the conserved sequence of tektin family proteins. Western blotting showed a single band having a molecular weight of 86 kDa in the mouse testis. Immunohistochemistry of the testis showed that tektin-t is localized in the flagella of elongating spermatids from developmental step 15 to maturity.     

A HMG-CoA reductase inhibitor improved regression of atherosclerosis in the rabbit aorta without affecting serum lipid levels: possible relevance of up-regulation of endothelial NO synthase mRNA.

We determined the role of Fluvastatin: HMG-CoA reductase inhibitor on the regression of atherosclerosis following removal of dietary cholesterol. Male rabbits fed a 0.5% cholesterol diet for 12 weeks were divided into three groups: A1, hypercholesterolemic; A2, fed a regular diet for an 12 additional weeks; and A3, fed a regular diet with fluvastatin (2 mg/kg/day). Fluvastatin treatment (A3) did not affect serum lipid levels compared with A2. However, it decreased the atherosclerotic area in the aortic arch and decreased total and esterified cholesterol concentrations in the descending aorta. Tone-related basal NO release in the thoracic aorta was larger in A3 than in A2. eNOS mRNA in vessel was determined by competitive RT-PCR assay. It increased in A1, compared with normal aorta and decreased in A2; however, it did not decrease in A3. This is the first report of a decrease in eNOS mRNA in atherosclerosis after removal of dietary cholesterol and a reversal of it by a HMG-CoA reductase inhibitor, which may contribute to the regression of atherosclerosis.     

Calcification process dynamics in coral primary polyps as observed using a calcein incubation method

Calcification processes are largely unknown in scleractinian corals. In this study, live confocal imaging was used to elucidate the spatiotemporal dynamics of the calcification process in aposymbiotic primary polyps of the coral species Acropora digitifera. The fluorophore calcein was used as a calcium deposition marker and a visible indicator of extracellular fluid distribution at the tissue-skeleton interface (subcalicoblastic medium, SCM) in primary polyp tissues. Under continuous incubation in calcein-containing seawater, initial crystallization and skeletal growth were visualized among the calicoblastic cells in live primary polyp tissues. Additionally, the distribution of calcein-stained SCM and contraction movements of the pockets of SCM were captured at intervals of a few minutes. Our experimental system provided several new insights into coral calcification, particularly as a first step in monitoring the relationship between cellular dynamics and calcification in vivo. Our study suggests that coral calcification initiates at intercellular spaces, a finding that may contribute to the general understanding of coral calcification processes.     

Effect of inorganic polyphosphate in periodontitis in the elderly

Aim: Inorganic polyphosphate exists as chains of phosphate molecules and is distributed in osteoblasts, and regulates osteoblastic cell differentiation and bone matrix calcification. The purpose of this study was to clarify the effects of inorganic polyphosphate on periodontitis. Material and methods: Subgingival local irrigation with inorganic polyphosphate was studied in a randomised double‐blind study of 33 patients with periodontitis. Scaling and root planing were performed 1 week after the initial examination. Results: No significant differences between the inorganic polyphosphate group and control were detected in each item except IL‐1β. Patients in whom both the bleeding on probing and gingival index at 1 week had improved were significantly older in the inorganic polyphosphate group than in the control group (p < 0.05). Bone regeneration was seen in one case of the inorganic polyphosphate group. Conclusions: Inorganic polyphosphate was useful in the treatment of periodontitis in the elderly, indicating a probable effect of anti‐ageing, with similar bone regenerations occurring in both groups.     

Instrumental outcome devaluation with representation-mediated conditioning

In three experiments, rats were trained to perform two instrumental behaviours (R1 and R2) in the presence of discriminative stimuli (Sd1 and Sd2, respectively) to obtain a common food outcome (O1). Acquisition of the two discriminations was followed by switching the outcome accompanying R2 performance from O1 to a new one (O2). Experiment 1 showed paired presentations of O2 with a lithium chloride (LiCl) injection resulted in a reduction in the R2 performance. In the subsequent two experiments, each Sd was paired with LiCl injection and its effects on outcome consumption and instrumental performance were investigated. A reduction in the O2 consumption subsequent to the Sd devaluation was found in Experiments 2 and 3. Experiment 3 revealed a reduced R2 performance in an extinction test, following the animals’ consummatory access to the outcomes in training context. These results demonstrate representation-mediated outcome devaluation in the course of the Sd devaluation.     

The ecological impact of an introduced population on a native population in the firefly Luciola cruciata (Coleoptera: Lampyridae)

In Japan, Tatsuno Town has been famous for many Luciola cruciata fireflies emerging every summer at least since the 1920s. However, in the 1960s, L. cruciata fireflies were intentionally introduced from the Lake Biwa area into Matsuo-kyo, the most famous habitat of fireflies in that town. In this study, I examined ambient temperatures and flash rates of L. cruciata at four sites including Matsuo-kyo in the Tatsuno area and two sites in the Lake Biwa area. The linear regression of flash rates on temperatures indicated that the Matsuo-kyo population was distinct from the other three populations native to the Tatsuno area, but similar to the two populations native to the Lake Biwa area in terms of flash rates. These results were also supported by a recent molecular biological study, suggesting that the introduced fireflies had a strong ecological impact on the native ones at Matsuo-kyo. The present study emphasizes that we should not transport and release L. cruciata fireflies without careful consideration.     

Identifying conservation priority ponds of an endangered minnow, <Emphasis Type="Italic">Pseudorasbora pumila</Emphasis>, in the area invaded by <Emphasis Type="Italic">Pseudorasbora parva</Emphasis>

We investigated the occurrence pattern of the pond-living endangered cyprinid, Pseudorasbora pumila, and also compared its habitat characteristics with those of the congeneric invasive species, Pseudorasbora parva, in the contact zone. Comparison of 16 environmental variables among the P. pumila habitats, P. parva habitats, and unoccupied ponds revealed that conductivity was a common limitation factor of distribution of both species. We found that emergent vegetation occupancy along the pond bank was the most important factor determining P. pumila occurrence and that ponds with steep banks may have a low probability of containing P. parva. We constructed a logistic regression model to predict the establishment risk of P. parva in ponds occupied by P. pumila. The model demonstrated that more than half of the ponds exhibited a high establishment risk of P. parva. Principal component analysis using six parameters selected from stepwise logistic regression analysis revealed that seven unoccupied ponds had the potential to sustain P. pumila, suggesting that our study site is capable of supporting more P. pumila populations and expanding the current range.     

Morphological and mtDNA sequence studies on three crucian carps (Carassius: Cyprinidae) including a new stock from the Ob River system, Kazakhstan

Three morphologically and genetically distinct forms of the genus Carassius were collected from the Ob River system, Kazakhstan, Central Asia; Carassius carassius , Carassius gibelio gibelio and an unknown stock tentatively referred to as Carassius gibelio sub-species M. The last mentioned had 33–41 gill rakers, being intermediate between the other two forms (23–27 in C. carassius and 44–49 in C. g. gibelio ), and five scales in the upper transverse series, less than in the others. It also had a relatively larger erythrocyte suggesting triploidy and an mtDNA haplotype distinct from all other known crucian carps. Comparative mtDNA phylogenetic analysis suggested that C. gibelio gibelio in the Ob River system was introduced from China and the Amur River, the same possibly being true for European C. gibelio gibelio based on published haplotypes. C. gibelio sub-species M is thought to be more widely distributed in central Asia, probably extending as far west as European Russia.     

Current status of genetic disturbances in wild medaka populations (<Emphasis Type="Italic">Oryzias latipes</Emphasis> species complex) in Japan

We revealed the range and current status of genetic disturbances in wild medaka populations (Oryzias latipes species complex) using two DNA markers (cytb gene and b-marker). Genetic disturbances were detected in many wild populations throughout Japan and were primarily caused by artificial introduction of the commercial medaka variety, himedaka. We identified native medaka populations without introgressions, which may be significant conservation targets. To conserve the native genetic diversity of the medaka species complex, further introduction of himedaka should be prevented by educating the public about the current status and risks of introducing non-native medaka varieties into the wild.