Prevalence and species richness of trematode parasites only partially recovers after the 2011 Tohoku,Japan, earthquake tsunami

Trematode parasites have complex life cycles and use a variety of host species across different trophic levels. Thus, they can be used as indicators of disturbance and recovery of coastal ecosystems. Estuaries on the Pacific coast of northeastern Japan were heavily affected by the 2011 Tohoku earthquake tsunami. To evaluate the effect of the tsunami on the trematode community, we examined trematodes in the mud snail, Batillaria attramentaria, at five study sites (three sites severely exposed to the tsunami and two sites sheltered from the tsunami) in Sendai Bay for 2 years prior to and 8 years after the tsunami. While the trematode prevalence decreased at all study sites, the species richness decreased only at the sites exposed to the tsunami. Although parasitism increased over the study period post-tsunami, the community had not fully recovered 8 years after the event. Trematode community structure has changed every year since the tsunami and has not stabilised. This could be explained by the alteration of first and second intermediate host communities. Our study suggests that it will take more time for the recovery of the trematode community and the associated coastal ecosystem in the Tohoku region.     

Site-directed mutagenesis of two amino acid residues in cytochrome b559 α subunit that interact with a phosphatidylglycerol molecule (PG772) induces quinone-dependent inhibition of photosystem II activity

Photosynthesis Research - X-ray crystallographic analysis (1.9-Å resolution) of the cyanobacterial photosystem II (PSII) dimer showed the presence of five phosphatidylglycerol (PG) molecules...     

Characteristics of β-adrenergic receptors in longitudinal muscle membranes of rat uterus: Changes in kinetic properties of the receptor during gestation

Binding characteristics of β-adrenergic receptors of longitudinal muscle membranes isolated from different stages of pregnant rat myometrium were investigated using [³H]dihydroalprenolol. Between Days 15 and 21 of gestation, the ratio of β₁- and β₂-adrenergic receptors of longitudinal membranes was constant. The membranes were found to be predominant in β₂-adrenergic receptors. The concentration of longitudinal muscle β-adrenergic receptors increased significantly during the last 7 days of gestation. Kinetic binding studies implied that the affinity of the membrane β-adrenergic receptors decreased through a slight decrease in the association rate and a large increase in the dissociation rate with progression of pregnancy. A Scatchard plot indicated that longitudinal muscle in β-adrenergic receptors on Days 15 and 18 constitute a single class of independent sites. By contrast, the dissociation kinetics, the convex downward curvature in a Scatchard plot and a Hill coefficient (h) of less than 1.00 of [³H] DHA binding to β-receptors of muscle on Day 21 suggested the existence of negatively cooperative multiple binding sites for β-adrenergic ligand. These results suggest that changes in the dynamics of uterus β-adrenergic receptors play an important role in the onset of labor.     

Metal ion dependency of serine racemase from Dictyostelium discoideum

D-Serine is known to act as an endogenous co-agonist of the N-methyl-D-aspartate receptor in the mammalian brain and is endogenously synthesized from L-serine by a pyridoxal 5'-phosphate-dependent enzyme, serine racemase. Though the soil-living mycetozoa Dictyostelium discoideum possesses no genes homologous to that of NMDA receptor, it contains genes encoding putative proteins relating to the D-serine metabolism, such as serine racemase, D-amino acid oxidase, and D-serine dehydratase. D. discoideum is an attractive target for the elucidation of the unknown functions of D-serine such as a role in cell development. As part of the elucidation of the role of D-serine in D. discoideum, we cloned, overexpressed, and examined the properties of the putative serine racemase exhibiting 46% amino acid sequence similarity with the human enzyme. The enzyme is unique in its stimulation by monovalent cations such as Na(+) in addition to Mg(2+) and Ca(2+), which are well-known activators for the mammalian serine racemase. Mg(2+) or Na(+) binding caused two- to ninefold enhancement of the rates of both racemization and dehydration. The half-maximal activation concentrations of Mg(2+) and Na(+) were determined to be 1.2?μM and 2.2?mM, respectively. In the L-serine dehydrase reaction, Mg(2+) and Na(+) enhanced the k (cat) value without changing the K (m) value. Alanine mutation of the residues E207 and D213, which correspond to the Mg(2+)-binding site of Schizosaccharomyces pombe serine racemase, abolished the Mg(2+)- and Na(+)-dependent stimulation. These results suggest that Mg(2+) and Na(+) share the common metal ion-binding site.     

Overexpression of yccL (gnsA) and ydfY (gnsB) Increases Levels of Unsaturated Fatty Acids and Suppresses both the Temperature-Sensitive fabA6 Mutation and Cold-Sensitive secG Null Mutation of Escherichia coli

A multicopy suppressor of the cold-sensitive secG null mutation was isolated. The suppressor contained sfa and yccL, the former of which has been reported to be a multicopy suppressor of the fabA6 mutation carried by a temperature-sensitive unsaturated fatty acid auxotroph. Subcloning of the suppressor gene revealed that yccL, renamed gnsA (secG null mutant suppressor), was responsible for the suppression of both the secG null mutation and the fabA6 mutation. In contrast, the sfa gene did not suppress the fabA6 mutation. The ydfY (gnsB) gene, encoding a protein which is highly similar to GnsA, also suppressed both the secG null mutation and the fabA6 mutation. Although both gnsA and gnsB are linked to cold shock genes, the levels of GnsA and GnsB did not exhibit a cold shock response. A gnsA-gnsB double null mutant grew normally under all conditions examined; thus, the in vivo functions of gnsA and gnsB remain unresolved. However, overexpression of gnsA and gnsB stimulated proOmpA translocation of the secG null mutant at low temperature and caused a significant increase in the unsaturated fatty acid content of phospholipids. Taken together, these results suggest that an increase in membrane fluidity due to the increase in unsaturated fatty acids compensates for the absence of the SecG function, especially at low temperature.     

Size and placement of developing anterior teeth in immature Neanderthal mandibles from Dederiyeh Cave,Syria: Implications for emergence of the modern human chin

Evolutionary and functional significance of the human chin has long been explored from various perspectives including masticatory biomechanics, speech, and anterior tooth size. Recent ontogenetic studies have indicated that the spatial position of internally forming anterior teeth partially constrains adult mandibular symphyseal morphology. The present study therefore preliminarily examined the size and placement of developing anterior teeth in immature Neanderthal mandibles of Dederiyeh 1 and 2, compared with similarly‐aged modern humans (N = 16) and chimpanzees (N = 7) whose incisors are comparatively small and large among extant hominids, respectively. The Dederiyeh 1 mandible is described as slightly presenting a mental trigone and attendant mental fossa, whereas Dederiyeh 2 completely lacks such chin‐associated configurations. Results showed that, despite symphyseal size being within the modern human range, both Dederiyeh mandibles accommodated overall larger anterior dentition and displayed a remarkably wide bicanine space compared to those of modern humans. Dederiyeh 2 had comparatively thicker deciduous incisor roots and more enlarged permanent incisor crypts than Dederiyeh 1, but both Dederiyeh individuals exhibited a total dental size mostly intermediate between modern humans and chimpanzees. These findings potentially imply that the large deciduous/permanent incisors collectively distended the labial alveolar bone, obscuring an incipient mental trigone. It is therefore hypothesized that the appearance of chin‐associated features, particularly of the mental trigone and fossa, can be accounted for partly by developmental relationships between the sizes of the available mandibular space and anterior teeth. This hypothesis must be, however, further addressed with more referential samples in future studies. Am J Phys Anthropol 156:482–488, 2015. © 2014 Wiley Periodicals, Inc.     

The ciliary protein Nek8/Nphp9 acts downstream of Inv/Nphp2 during pronephros morphogenesis and left-right establishment in zebrafish

Nephronophthisis (NPHP) is an autosomal recessive cystic kidney disease. Among 12 reported Nphp gene products, Inv/Nphp2, Nphp3 and Nek8/Nphp9 are localized to the proximal segment in the primary cilium. However, the functional relationships are unknown. This study focused on phenotype analysis of nek8 knockdown embryos and the genetic relationship between nek8 and inv in zebrafish. Knockdown of nek8 produced both pronephric cysts and abnormal cardiac looping. Simultaneous knockdown of nek8 and inv synergistically increased the incidence of these defects. Interestingly, nek8 mRNA rescued inv morphant phenotypes, although inv mRNA could not rescue nek8 morphant phenotypes. These results suggest that Nek8 acts downstream of Inv function.     

Variation in photoinhibition among Sasa senanensis, Quercus mongolica, and Acer mono in the understory of a deciduous broad-leaved forest exposed to canopy gaps caused by typhoons

To elucidate mechanisms for tolerating sudden increases in light intensity following canopy gap formation, we investigated susceptibility to photoinhibition in the evergreen clonal plant bamboo, Sasa senanensis, and two deciduous broadleaf woody plants, Quercus mongolica, and Acer mono. We measured pre-dawn photochemical efficiency of photosystem II (F _v /F _m) in plants exposed to canopy gaps and in shade-grown plants through the month following gap formation. Photoinhibition (indicated by decreased F _v /F _m) was smallest in S. senanensis and largest in A. mono. S. senanensis had the highest area-based net CO₂ assimilation rate (A _area) and electron transport rate (ETR) under high light conditions. This species also had the highest leaf mass per area (LMA) and leaf nitrogen content per area (N _area). Higher values of LMA and N _area under shade conditions probably contribute to circumvent photoinhibition through maintenance of a higher ETR capacity. Q. mongolica, a gap-dependent species, had properties intermediate between S. senanensis and A. mono; it appeared less susceptible to photoinhibition than the shade-tolerant A. mono. None of the species examined had increased photosynthetic capacity 1 month after gap formation, indicating that shade-grown leaves were unable to fully acclimate to increased light.     

Deep intra-uterine artificial inseminations using cryopreserved spermatozoa in beluga (Delphinapterus leucas)

Artificial insemination (AI) with liquid-stored spermatozoa and sperm cryopreservation using directional freezing (DF) have been successful in the beluga. This study built on this foundation to develop a deep intra-uterine AI technique with frozen-thawed semen in beluga. Forty-two ejaculates from one male were cryopreserved using DF technology and subsequently used for 10 insemination attempts with seven females. Percentage pre- and post-thaw progressive motility and viability were (mean ± SD) 73.0 ± 12.2, 38.4 ± 8.8, 88.0 ± 0.1, and 59.3 ± 15.7%, respectively. A series of GnRH injections (3 x 250 μg, IV, 1.5 to 2 h apart) were used to induce ovulation, once a growing follicle >2.5 cm in diameter was visualized via trans-abdominal ultrasonography. Artificial insemination was performed at 30.1 ± 3.8 h post-initial GnRH injection with semen deposited in the uterine horn, 92.6 ± 16.2 cm beyond the genital opening using a flexible endoscope. The external cervical os (cEOS) was located beyond a series of 5 to 10 vaginal rings, 44.8 ± 9.3 cm from the external genital opening. The internal bifurcation of the uterus was 27 ± 6.8 cm beyond the cEOS. Ovulation occurred at 8.5 ± 7.6 h post-AI. Two of 10 inseminations (20%) resulted in pregnancy. The first pregnancy resulted in twins; both calves were born 442 d after AI, with one surviving. The second pregnancy is ongoing. These findings represent the first successful application of AI using frozen-thawed semen in beluga, and are important examples of how assisted reproductive technologies can provide tools for the global management of threatened species.     

Physiological effects and active ingredients of Viburnum dilatatum Thunb fruits on oxidative stress

The fruit of Viburnum dilatatum Thunb, called gamazumi in Japan, showed the strong antioxidant activities, and its preventive effects on oxidative stress and active ingredients were investigated. Male rats were subjected to water immersion restraint stress for 6 hours, after ingestion of the gamazumi crude extract (GCE) for 2 weeks. The formation of gastric ulcer was reduced, and the lipid peroxidation in plasma and organs also lowered in rats ingested GCE. In the streptozotocin-induced diabetic rats given GCE for 10 weeks, inhibition of lipid peroxidation in plasma, erythrocytes and organs was observed, and the increase of plasma glucose level also lowered. On the other hand, two cyanidin glycosides, two chlorogenic acids and quercetin were identified, and especially cyanidin 3-sambubioside (Cy 3-sam) showed the strong radical scavenging activity. It is suggested that Cy 3-sam is a key compound contributing to the physiological effects of V. dilatatum fruit.