Subcellular localization of ferredoxin-NADP+ oxidoreductase in phycobilisome retaining oxygenic photosysnthetic organisms

Ferredoxin-NADP⁺ oxidoreductase (FNR) catalyzing the terminal step of the linear photosynthetic electron transport was purified from the cyanobacterium Spirulina platensis and the red alga Cyanidium caldarium. FNR of Spirulina consisted of three domains (CpcD-like domain, FAD-binding domain, and NADP⁺-binding domain) with a molecular mass of 46 kDa and was localized in either phycobilisomes or thylakoid membranes. The membrane-bound FNR with 46 kDa was solublized by NaCl and the solublized FNR had an apparent molecular mass of 90 kDa. FNR of Cyanidium consisted of two domains (FAD-binding domain and NADP⁺-binding domain) with a molecular mass of 33 kDa. In Cyanidium, FNR was found on thylakoid membranes, but there was no FNR on phycobilisomes. The membrane-bound FNR of Cyanidium was not solublized by NaCl, suggesting the enzyme is tightly bound in the membrane. Although both cyanobacteria and red algae are photoautotrophic organisms bearing phycobilisomes as light harvesting complexes, FNR localization and membrane-binding characteristics were different. These results suggest that FNR binding to phycobilisomes is not characteristic for all phycobilisome retaining oxygenic photosynthetic organisms, and that the rhodoplast of red algae had possibly originated from a cyanobacterium ancestor, whose FNR lacked the CpcD-like domain.     

Racial and ethnic differences in pediatric obesity-prevention counseling: national prevalence of clinician practices

Objective: To assess the frequency of clinician‐reported delivery of obesity‐prevention counseling (OPC) at well‐child visits; evaluating for racial/ethnic discrepancies. Methods and Procedures: Combined, weighted well‐child visit data from the National Ambulatory Medical Care Survey (NAMCS) and National Hospital Ambulatory Medical Care Survey (NHAMCS) from 2001 to 2004 were analyzed for patients aged 4–18 years. Obesity‐prevention counseling was defined as the combined delivery of diet/nutrition and exercise counseling. Patients receiving over‐ or underweight related diagnoses were excluded. Counseling frequencies were calculated. Multivariate logistic regression models examined the relationship of OPC with race, ethnicity, region, provider, sex, age, and payor type. Results: Of 55,695,554 (weighted) visits, 24.4% included OPC (90.8% of these from NAMCS). 15.4% of Hispanic patients received OPC compared to 28.8% of non‐Hispanics. Frequencies were similar between Whites and Blacks (25.0 and 27.1%). Patients with private insurance received more counseling (26.9%) than Medicaid (19.1%) or self‐pay (15.1%). In logistic regression models, non‐Hispanics were more likely to receive OPC (odds ratio (OR) = 1.94; confidence interval (CI) = 1.13–3.32), and patients in the West were less likely to receive OPC (OR = 0.39; CI = 0.18–0.85). Payor type was not predictive in regression analysis. Patients in hospital‐based practices received less OPC (11.9% vs. 25.7% with OR = 0.40; CI =0.22–0.74). Discussion: Obesity prevention, like treatment, is a complex and multifactorial process. With the documented racial and ethnic disparities in rates of pediatric obesity, reasons for discrepancies in the provision of OPC must be further investigated as preventive strategies are formulated.     

Sex pheromone biosynthesis in Ostrinia zaguliaevi, a congener of the European corn borer moth O. nubilalis

In order to clarify the biochemical basis to the divergence of sex pheromones in the genus Ostrinia (Lepidoptera: Crambidae), the pheromone biosynthetic pathway in O. zaguliaevi, a close relative of the European corn borer O. nubilalis, was investigated. Deuterium-labeled hexadecanoic or tetradecanoic acids were topically applied to the surface of the pheromone gland, and the incorporation of the label into pheromone components and their putative precursors was determined. It was suggested that the two components shared by O. zaguliaevi and O. nubilalis, (E)-11- and (Z)-11-tetradecenyl acetates, are biosynthesized from hexadecanoic acid through one round of chain shortening, Delta11 desaturation, reduction, and acetylation. An additional component specifically found in O. zaguliaevi, (Z)-9-tetradecenyl acetate, is likely to be produced by delta11 desaturation of hexadecanoic acid, one round of chain shortening, reduction, and acetylation. Non-production of (Z)-9-tetradecenyl acetate in O. nubilalis was suggested to be due to the blockage of chain shortening from (Z)-11-hexadecenoate to (Z)-9-tetradecenoate.     

Light, nutrients and primary productivity in Lake Biwa: An evaluation of the current ecosystem situation

Simple correlation and multiple regression analyses were performed to examine the relationship between primary productivity and environmental factors in the north basin of Lake Biwa. The primary production rates used in the analyses were estimated monthly or bimonthly during the growing season (April–November) in 1992, 1996 and 1997 with the ¹³C method. Elemental (C, N and P) contents of seston were used to assess nutrient conditions. Analyses revealed that 86% of variance in depth-integrated primary production rates (areal PP) can be explained by changes in light intensity, and sestonic C, N and P concentrations. Water temperature had no effect on areal PP. To assess relative effects of light and nutrients on PP, the P:B ratio was estimated by normalizing PP with sestonic C. The areal P:B ratio correlated most significantly with the sestonic N:P ratio, followed by light intensity. When regression analyses were made at each depth, however, the P:B ratio correlated significantly only with the sestonic N:P ratio at 0 and 1 m depths, while light intensity was also incorporated into the regressions at deeper than 2.5 m. In these regressions, the P:B ratio was negatively correlated with sestonic N:P ratio but positively with light intensity. The results suggest that the primary production rate in this lake was mainly limited by P relative to N supply rates, but was not free from light limitation in a large part of the epilimnion. In Lake Biwa, the vertical water mixing regime as well as the nutrient supply seem to be important in determining the growth and composition of primary producers, since the surface mixing layer extends into 10–15 m depths during most of the growing season.     

Correlation analysis between fatty acid compositions of zooplankter individuals, fed on different phytoplankton species by means of pyrolysis–gas chromatography combined with on-line methylation

Pyrolysis–gas chromatography (Py–GC) combined with on-line methylation was applied to a correlation analysis between the distributions of fatty acid components in the lipids of zooplankter individuals and those of ingested algae using principal component analysis (PCA). Py–GC in the presence of organic alkali, tetramethylammonium hydroxide (TMAH), was used to estimate the apparent distributions of fatty acid components contained in a single individual zooplankter weighing several tens of micrograms and a small sample size of ingested algae samples in the order of 10 μg. The observed fatty acid compositions were used as a database for the PCA in order to discriminate the zooplankton and ingested algae samples. The result obtained indicated that the fatty acid compositions of zooplankton individuals used in this work were significantly reflected in those of their ingested food in spite of some contribution from isomerization and/or elongation of fatty acid components during digestion of the ingested algae phytoplankton in living zooplankters.     

Identification of the sex pheromone of Ostrinia palustralis

By means of gas chromatography with electroantennographic detection, gas chromatography-mass spectrometry and a series of bioassays, (E)-11-tetradecenyl acetate (E11-14:OAc) and (Z)-11-tetradecenyl acetate (Z11-14:OAc) at a ratio of 99:1 were identified as female sex pheromone components of Ostrinia palustralis. The average amounts of E11- 14:OAc and Z11-14:OAc in a single sex pheromone gland were 37.2±24.4 ng and 0.3±0.2 ng, respectively. In a wind-tunnel bioassay, the binary blend of E11- and Z11-14:OAc elicited the same male behavioral responses as did virgin females.     

Dual abnormal effects of mutant MITF encoded by Mi(wh) allele on mouse mast cells: decreased but recognizable transactivation and inhibition of transactivation

Structural localization of a peptide region, KRQPRNPKTDKLVNE, in the catalytic subunit of (Na(+) + K(+))-ATPase was investigated using a specific antibody directed against this peptide in cultured African green monkey kidney CV-1 cells. Immunofluorescence staining of frozen cell sections shows that an anti-KRQPRNPKTDKLVNE antibody (SSA95) interacts with its antigenic site and binds to the extracellular side of the cell membrane. Indirect immunofluorescence and flow cytometric analyses confirmed the presence of this epitope on intact cell surfaces. These results suggest that the KRQPRNPKTDKLVNE region of the (Na(+) + K(+))-ATPase is expressed on the cellular membrane surface.     

Insulin-like Growth Factor Signaling Pathway Involved in Regulating Longevity of Rotifers

Rotifers have been used to study the mechanisms of ageing for more than a century, but the underlying molecular basis of ageing in rotifers is largely unknown. The insulin/insulin-like growth factor (IGF-1) signaling pathway has been found to regulate the lifespan of evolutionarily distinct eukaryotes from yeast to mammals. We therefore assume that the insulin/IGF-1 pathway is a candidate for regulating the rotifer’s lifespan. Accordingly, we examined the action of an inhibitor to PI3-kinase involved in the pathway for the rotifer Brachionus plicatilis O. F. Müller. This kinase was first discovered as age-1 to regulate the longevity of Caenorhabditis elegans. As expected, the inhibitor treatment resulted in the extension of lifespan by 30% compared to the reference group without the treatment, whereas reproductive characters were not apparently changed. These results were consistent with those observed in C. elegans, suggesting that the lifespan of B. plicatilis is likely to be regulated by the signaling pathway involving PI3-kinase.