Lung Surfactant Levels are Regulated by Ig-Hepta/GPR116 by Monitoring Surfactant Protein D

Lung surfactant is a complex mixture of lipids and proteins, which is secreted from the alveolar type II epithelial cell and coats the surface of alveoli as a thin layer. It plays a crucial role in the prevention of alveolar collapse through its ability to reduce surface tension. Under normal conditions, surfactant homeostasis is maintained by balancing its release and the uptake by the type II cell for recycling and the internalization by alveolar macrophages for degradation. Little is known about how the surfactant pool is monitored and regulated. Here we show, by an analysis of gene-targeted mice exhibiting massive accumulation of surfactant, that Ig-Hepta/GPR116, an orphan receptor, is expressed on the type II cell and sensing the amount of surfactant by monitoring one of its protein components, surfactant protein D, and its deletion results in a pulmonary alveolar proteinosis and emphysema-like pathology. By a coexpression experiment with Sp-D and the extracellular region of Ig-Hepta/GPR116 followed by immunoprecipitation, we identified Sp-D as the ligand of Ig-Hepta/GPR116. Analyses of surfactant metabolism in Ig-Hepta^+/+ and Ig-Hepta^−/− mice by using radioactive tracers indicated that the Ig-Hepta/GPR116 signaling system exerts attenuating effects on (i) balanced synthesis of surfactant lipids and proteins and (ii) surfactant secretion, and (iii) a stimulating effect on recycling (uptake) in response to elevated levels of Sp-D in alveolar space.     

Functional activity of RLIM/Rnf12 is regulated by phosphorylation-dependent nucleocytoplasmic shuttling

The X-linked gene Rnf12 encodes the ubiquitin ligase really interesting new gene (RING) finger LIM domain–interacting protein (RLIM)/RING finger protein 12 (Rnf12), which serves as a major sex-specific epigenetic regulator of female mouse nurturing tissues. Early during embryogenesis, RLIM/Rnf12 expressed from the maternal allele is crucial for the development of extraembryonic trophoblast cells. In contrast, in mammary glands of pregnant and lactating adult females RLIM/Rnf12 expressed from the paternal allele functions as a critical survival factor for milk-producing alveolar cells. Although RLIM/Rnf12 is detected mostly in the nucleus, little is known about how and in which cellular compartment(s) RLIM/Rnf12 mediates its biological functions. Here we demonstrate that RLIM/Rnf12 protein shuttles between nucleus and cytoplasm and this is regulated by phosphorylation of serine S214 located within its nuclear localization sequence. We show that shuttling is important for RLIM to exert its biological functions, as alveolar cell survival activity is inhibited in cells expressing shuttling-deficient nuclear or cytoplasmic RLIM/Rnf12. Thus regulated nucleocytoplasmic shuttling of RLIM/Rnf12 coordinates cellular compartments during mammary alveolar cell survival.     

Expression patterns of dachshund during head development of Gryllus bimaculatus (cricket)

We report that Gryllus bimaculatus dachshund (Gbdac), a cricket homologue of Drosophila dachshund (Dmdac), is expressed in the developing eye and brain. During brain development, Gbdac was first expressed in the medial head region, corresponding to a part of developing protocephalic region, and expressed in the primordial and adult Kenyon cells. During eye development, Gbdac was first expressed in the lateral head region, becoming to the eye primordium and a part of the deutocerebrum. Then, Gbdac was expressed in the posterior region of the eye primordium, prior to the formation of compound eyes. The expression domain shifted to the anterior domain concomitantly with the movement of morphogenetic furrows. Gbdac was also expressed in the developing optic lobes during differentiation of the retina. These expression patterns were compared with those of Dmdac. We found that although developmental processes of the Gryllus eye and brain differ from those of the Drosophila ones, the expression patterns of Gbdac are essentially similar to those of the Dmdac.     

Purification and Properties of Lytic Enzymes from Streptomyces globisporus 1829

Two lytic enzymes capable of lysing Streptococcus mutans have been purified to give a single band on disc-gel electrophoresis, respectively. The M–1 and M–2 enzymes were both proved to be N-acetylmuramidases. However, these enzymes were entirely different on their enzymatic properties. The molecular weights were about 20,000 and 11,000 for M–1 and M–2 enzymes, respectively, The maximal lytic activity of M–1 enzyme was obtained at ionic strength 0.05, while lytic activity of M–2 enzyme did not change within the ionic strength range of 0 to 0.05. The M–1 enzyme constituted the majority of the total lytic activity against the cell walls of Streptococcus mutans BHT of cultured filtrate. The M–2 enzyme showed less specific lytic activity on the cell walls of Streptococcus mutans BHT than M–1 enzyme.     

Osteoblastic activity and estrogenic response in the regenerating scale of goldfish, a good model of osteogenesis

Osteogenesis in the teleost was morphologically observed using regenerating scales of goldfish. Histological observations indicated that osteoblasts around the regenerating scales on days 7 to 10 were greater in size and number than those at other stages. Therefore, further experiments were carried out to examine the activity of osteoblasts in the regenerating period. To quantify their osteoblastic activities, scales on the left side of the body were taken, and the regenerating scales were then used to measure the activities of alkaline phosphatase (ALP), a marker of osteoblasts, on days 7, 10, and 15. The ontogenic scales on the right side of the body were also collected and used to measure ALP activity on the same days. Osteoblasts at all stages of regenerating scales were more active than those in the remaining ontogenic scales. The regenerating scales on day 10 had the highest activity. Furthermore, we found that estrogen receptor (ER) mRNA was expressed in the regenerating scales because estrogen participates in osteoblastic growth and differentiation in mammals. Therefore, using a scale culture system reported previously, the estrogenic response was examined in the ontogenic and regenerating scales on day 10. The reactivity was much higher in regenerating scales, although estrogen treatment significantly activated the osteoblastic activities in both scales. We are the first to demonstrate that ER is expressed in regenerating scales and that estrogen participates in osteogenesis as it does in mammalian bone. Our findings strongly suggest that regenerating scales can be used as a model of osteogenesis in vertebrates.     

Analysis of flavonoids in flower petals of soybean near-isogenic lines for flower and pubescence color genes

W1, W3, W4, and Wm genes control flower color, whereas T and Td genes control pubescence color in soybean. W1, W3, Wm, and T are presumed to encode flavonoid 3'5'-hydroxylase (EC 1.14.13.88), dihydroflavonol 4-reductase (EC 1.1.1.219), flavonol synthase (EC 1.14.11.23), and flavonoid 3'-hydroxylase (EC 1.14.13.21), respectively. The objective of this study was to determine the structure of the primary anthocyanin, flavonol, and dihydroflavonol in flower petals. Primary component of anthocyanin in purple flower cultivars Clark (W1W1 w3w3 W4W4 WmWm TT TdTd) and Harosoy (W1W1 w3w3 W4W4 WmWm tt TdTd) was malvidin 3,5-di-O-glucoside with delphinidin 3,5-di-O-glucoside as a minor compound. Primary flavonol and dihydroflavonol were kaempferol 3-O-gentiobioside and aromadendrin 3-O-glucoside, respectively. Quantitative analysis of near-isogenic lines (NILs) for flower or pubescence color genes, Clark-w1 (white flower), Clark-w4 (near-white flower), Clark-W3w4 (dilute purple flower), Clark-t (gray pubescence), Clark-td (near-gray pubescence), Harosoy-wm (magenta flower), and Harosoy-T (tawny pubescence) was carried out. No anthocyanins were detected in Clark-w1 and Clark-w4, whereas a trace amount was detected in Clark-W3w4. Amount of flavonols and dihydroflavonol in NILs with w1 or w4 were largely similar to the NILs with purple flower suggesting that W1 and W4 affect only anthocyanin biosynthesis. Amount of flavonol glycosides was substantially reduced and dihydroflavonol was increased in Harosoy-wm suggesting that Wm is responsible for the production of flavonol from dihydroflavonol. The recessive wm allele reduces flavonol amount and inhibits co-pigmentation between anthocyanins and flavonols resulting in less bluer (magenta) flower color. Pubescence color genes, T or Td, had no apparent effect on flavonoid biosynthesis in flower petals.     

Novel molecular identification methods for the larger black flour beetle,Cynaeus angustus (Coleoptera: Tenebrionidae)

Two new methods were developed for identifying Cynaeus angustus (LeConte) (Coleoptera: Tenebrionidae) by DNA amplification using simplex and real-time PCR targeting the cytochrome c oxidase subunit I (COI) sequence reported previously. The specificities of the PCR primers and probe were also confirmed by the two PCR methods using the 22 main stored-product insect species, including DNA samples from nine tenebrionid beetle species. The results showed that the newly developed simplex and real-time PCR-based methods have sufficient specificity for analysis. The limits of detection for C. angustus total DNA by the simplex and multiplex PCR were 320 fg and 20 pg, respectively.

     

Candidusin A and B: New p-Terphenyls with Cytotoxic Effects on Sea Urchin Embryos

Three fungal trichothecenes, verrucarin A, roridin A and 8-β-hydroxyroridin E, were isolated as callus-initiating promoters from Myrothecium sp. 301. These trichothecenes promoted callus induction, synergistically coupled with a low concentration of 2,4-dichlorophenoxyacetic acid.