A yield control approach to assess phytoavailability of Zn and Cu in irradiated,composted sewage sludges and composted manure in field experiments: II. Copper

Organic wastes such as sewage sludges contain copper (Cu). Increased attention to environmental protection requires that wastes be treated with pathogen-eliminating procedures before application to farmland. It is not clear, however, if such procedures affect the plant availability of Cu in the wastes. This 2-year field research investigated the effect of irradiation and composting on Cu availability in sludges and manure using a yield control approach. Four organic wastes [digested and dewatered (DSS), digested and irradiated (DISS), composted (DICSS) sewage sludges and composted livestock manure (CLM)] were applied at four rates (10, 20, 30 and 40 t solid ha^–1 year^–1) with supplemented N and K fertilizers. A control treatment (CT) received N and K fertilizers only. Beans, lettuce and petunias were grown in first year and lettuce were harvested twice in second year. Beans appeared to have a strong ability to absorb Cu compared with the other test crops. In general, crop Cu concentration responses to Cu applied in DSS and DISS were well described by quadratic equations. Tested by a paired t-test, Cu concentration in bean pods was higher in DISS than in DSS treatment, indicating that irradiation increased phytoavailability of Cu. However, the parabolic response of crop Cu to Cu applied in DISS, suggesting that the increases were confined to the lower rates of DISS. Copper applied in DICSS did not increase Cu concentration in any of the test crops. At a given level of applied Cu, crop Cu tended to be lower in DICSS than in DSS or DISS treatment. Sludge composting depressed phytoavailability of Cu. Copper concentration in CLM was much lower than in sludges and sludge composts, but application of CLM increased Cu concentration in bean pods. The pattens of Cu concentration in the two cuts of lettuce in 1991 to Cu applied in CLM were similar, where low rates of CLM application slightly reduced Cu concentration, then the Cu concentration increased with increased rates. The dynamics of available Cu supply were different in the sludge composts and manure composts.     

Stress to endoplasmic reticulum of mouse osteoblasts induces apoptosis and transcriptional activation for bone remodeling

ATF4 is an essential regulator in osteogenesis as well as in stress responses to the endoplasmic reticulum (ER). We addressed a question: Does ER stress to osteoblasts upregulate ATF4 expression? If so, do they exhibit ATF4-mediated bone remodeling or apoptosis? ER stress, induced by Thapsigargin and tunicamycin, elevated a phosphorylated form of eIF2alpha and ATF4, but the cellular fate depended on treatment duration. The treatment for 1h, for instance, activated Runx2, and type I collagen, while the treatment for 24h induced apoptosis. Our observations suggest that there is a threshold for ER stress and osteoblasts present a bi-phasic pattern of their fate.     

Morphological and ecological adaptation of Basterotia bivalves (Galeommatoidea: Sportellidae) to symbiotic association with burrowing echiuran worms

The burrows created by benthos in tidal flats provide various habitats to other organisms. Echiuran burrows are unique among these in being persistently disturbed by the host's undulating activity, but little is known on how symbionts adapt to such a unique habitat. We report here the morphological and ecological adaptation by two bivalve species of Basterotia (Sportellidae), including one new species, which are commensals with burrowing echiuran worms. The burrows of Ikedosoma gogoshimense were inhabited by Basterotia gouldi at intertidal gravelly mud flats in the central Seto Inland Sea, whereas those of Ochetostoma erythrogrammon were inhabited by Basterotia carinata n. sp. at an intertidal gravelly coral-sand flat at Amami-Ohshima Island. Both bivalve species were found embedded in the burrow wall with their posterior inhalant and exhalant apertures gaping to the burrow lumen, suggesting that they utilize the water currents created by host echiurans. The posteriorly robust, laterally inflated shell with developed carina is considered an adaptation to symbiotic life, as it is exposed to pressure caused by the host's persistent undulating activity. Females of Basterotia bivalves were larger than males, suggesting size-dependent sex change, and possessed brooded veligers in the ctenidium. Our findings suggest that species-specific intimate association with echiurans may be widespread among the Sportellidae bivalves, whose biology remains poorly understood.     

A brief review of bone adaptation to unloading

Weight-bearing bone is constantly adapting its structure and function to mechanical environments. Loading through routine exercises stimulates bone formation and prevents bone loss, but unloading through bed rest and cast immobilization as well as exposure to weightlessness during spaceflight reduces its mass and strength. In order to elucidate the mechanism underlying unloading-driven bone adaptation, ground-based in vitro and in vivo analyses have been conducted using rotating cell culturing and hindlimb suspension. Focusing on gene expression studies in osteoblasts and hindlimb suspension studies, this minireview introduces our recent understanding on bone homeostasis under weightlessness in space. Most of the existing data indicate that unloading has the opposite effects to loading through common signaling pathways. However, a question remains as to whether any pathway unique to unloading （and not to loading） may exist.     

Mitochondrial dynamics in plant male gametophyte visualized by fluorescent live imaging

Visualization of organelles in living cells is a powerful method for studying their dynamic behavior. Here we attempted to visualize mitochondria in angiosperm male gametophyte (pollen grain from Arabidopsis thaliana) that are composed of one vegetative cell (VC) and two sperm cells (SCs). Combination of mitochondria-targeted fluorescent proteins with VC- or SC-specific expression allowed us to observe the precise number and dynamic behavior of mitochondria in the respective cell types. Furthermore, live imaging of SC mitochondria during double fertilization confirmed previous observations, demonstrated by electron microscopy in other species, that sperm mitochondria enter into the egg and central cells. We also attempted to visualize mutant mitochondria that were elongated due to a defect in mitochondrial division. This mutant phenotype was indeed detectable in VC mitochondria of a heterozygous F(1) plant, suggesting active mitochondrial division in male gametophyte. Finally, we performed mutant screening and isolated a putative mitochondrial protein transport mutant whose phenotype was detectable only in haploid cells. The transgenic materials presented in this work are useful not only for live imaging but also for studying mitochondrial functions by mutant analysis.     

Diversity,abundance, and activity of archaeal populations in oil-contaminated groundwater accumulated at the bottom of an underground crude oil storage cavity

Fluorescence in situ hybridization has shown that cells labeled with an Archaea-specific probe (ARCH915) accounted for approximately 10% of the total cell count in oil-contaminated groundwater accumulated at the bottom of an underground crude oil storage cavity. Although chemical analyses have revealed vigorous consumption of nitrate in cavity groundwater, the present study found that the methane production rate was higher than the nitrate consumption rate. To characterize the likely archaeal populations responsible for methane production in this system, fragments of 16S ribosomal DNA (rDNA) were amplified by PCR using eight different combinations of universal and Archaea-specific primers. Sequence analysis of 324 clones produced 23 different archaeal sequence types, all of which were affiliated with the kingdom EURYARCHAEOTA: Among them, five sequence types (KuA1, KuA6, KuA12, KuA16, and KuA22) were obtained in abundance. KuA1 and KuA6 were closely related to the known methanogens Methanosaeta concilii (99% identical) and Methanomethylovorans hollandica (98%), respectively. Although no closely related organism was found for KuA12, it could be affiliated with the family METHANOMICROBIACEAE: KuA16 and KuA22 showed substantial homology only to some environmental clones. Both of these branched deeply in the Euryarchaeota, and may represent novel orders. Quantitative competitive PCR showed that KuA12 was the most abundant, accounting for approximately 50% of the total archaeal rDNA copies detected. KuA1 and KuA16 also constituted significant proportions of the total archaeal rDNA copies (7 and 17%, respectively). These results suggest that limited species of novel archaea were enriched in the oil storage cavity. An estimate of specific methane production rates suggests that they were active methanogens.     

Mechanisms for the apoptosis of small cell lung cancer cells induced by anti-GD2 monoclonal antibodies: roles of anoikis

Anti-GD2 ganglioside antibodies could be a promising, novel therapeutic approach to the eradication of human small cell lung cancers, as anti-GD2 monoclonal antibodies (mAbs) induced apoptosis of small cell lung cancer cells in culture. In this study, we analyzed the mechanisms for the apoptosis of these cells by anti-GD2 mAbs and elucidated the mechanisms by which apoptosis signals were transduced via reduction in the phosphorylation levels of focal adhesion kinase (FAK) and the activation of a MAPK family member, p38, upon the antibody binding. Knock down of FAK resulted in apoptosis and p38 activation. The inhibition of p38 activity blocked antibody-induced apoptosis, indicating that p38 is involved in this process. Immunoprecipitation-immunoblotting analysis of immune precipitates with anti-FAK or anti-integrin antibodies using an anti-GD2 mAb revealed that GD2 could be precipitated with integrin and/or FAK. These results suggested that GD2, integrin, and FAK form a huge molecular complex across the plasma membrane. Taken together with the fact that GD2+ cells showed marked detachment from the plate during apoptosis, GD2+ small cell lung cancer cells seemed to undergo anoikis through the conformational changes of integrin molecules and subsequent FAK dephosphorylation.