BMP and Hh signaling affects primordial germ cell division in Drosophila

The germline is segregated from the remainder of the soma during early embryonic development in metazoan species. In Drosophila, female primordial germ cells (PGCs) continue to proliferate during larval development, and become germline stem cells at the early pupal stage. To elucidate the roles of growth factors in larval PGC division, we examined expression patterns of a bone morphogenetic protein (BMP) growth factor, Decapentaplegic (Dpp), and Hedgehog (Hh), along with factors downstream of each, in the ovary during larval development. Dpp signaling appeared in the ovarian soma from early larval development, and was prominent in the terminal filament cells at late larval stage, whereas Hh appeared in the ovarian soma and PGCs from the third instar larval stage. The number of PGCs decreased when components of these signal transduction pathways were abrogated by RNAi in the PGCs, indicating that both Dpp and Hh signals directly regulate PGC proliferation. Experiments on the up- and down-regulation of Dpp and Hh with a tissue-specific Gal4 driver indicated that Dpp and Hh act as extrinsic and autocrine growth factors. Furthermore, heat-pulse experiments with hs-Gal4 showed that Dpp is active in PGC proliferation throughout larval development, whereas Hh has effects only during late larval development. In addition to Dpp, the reduction of Glass bottom boat (Gbb), another BMP molecule, caused a decrease in the number of PGCs and initiation of larval PGCs differentiation into cystocytes, indicating that Gbb functions to promote PGC division and repress differentiation.     

Increased expression of co-chaperone HOP with HSP90 and HSC70 and complex formation in human colonic carcinoma

Co-chaperone HOP (also called stress-inducible protein 1) is a co-chaperone that interacts with the cytosolic 70-kDa heat shock protein (HSP70) and 90-kDa heat shock protein (HSP90) families using different tetratricopeptide repeat domains. HOP plays crucial roles in the productive folding of substrate proteins by controlling the chaperone activities of HSP70 and HSP90. Here, we examined the levels of HOP, HSC70 (cognate of HSP70, also called HSP73), and HSP90 in the tumor tissues from colon cancer patients, in comparison with the non-tumor tissues from the same patients. Expression level of HOP was significantly increased in the tumor tissues (68% of patients, n = 19). Levels of HSC70 and HSP90 were also increased in the tumor tissues (95% and 74% of patients, respectively), and the HOP level was highly correlated with those of HSP90 (r = 0.77, p < 0.001) and HSC70 (r = 0.68, p < 0.01). Immunoprecipitation experiments indicated that HOP complexes with HSC70 or HSP90 in the tumor tissues. These data are consistent with increased formation of co-chaperone complexes in colon tumor specimens compared to adjacent normal tissue and could reflect a role for HOP in this process.     

Olfactory Imprinting of Amino Acids in Lacustrine Sockeye Salmon

Juvenile salmon have an olfactory ability to imprint their natal stream odors, but neither the odor properties of natal stream water nor the imprinting timing and duration have been clarified as yet. Here we show, using electrophysiological and behavioral experiments, that one-year-old lacustrine sockeye salmon (Oncorhynchus nerka) can be imprinted around the stage of parr-smolt transformation (PST) by a single amino acid, 1 µM L-proline (Pro), or L-glutamic acid (Glu). We also show by real-time PCR that changes occur in mRNA levels of the salmon olfactory imprinting-related gene (SOIG) around PST. The electro-olfactogram (EOG) responses of test fish exposed to Pro in March (before PST) and April–June (during PST) for 2 weeks were significantly (1.7-fold) greater than those of non-exposed control fish, but not those of test fish exposed in July (after PST). When Pro and control water were added to the water inlets of a two-choice test tank during the spawning season 2 years after the test water exposure, 80% of maturing and matured test fish exposed before and during PST showed a preference for Pro, whereas those exposed after PST did not. The EOG response of test fish exposed to Pro or Glu for 1 hour, 6 hours, 1 day, 7 days, or 14 days in May revealed that only the response after 14 days of exposure was significantly (1.8-fold) greater than the control. The expression levels of SOIG mRNA increased before and during PST, and decreased after PST. We conclude that one-year-old lacustrine sockeye salmon can be imprinted by a single amino acid before and during PST, and that imprinting requires exposure for at least 14 days.     

Study on immunocapture-chemiluminescence assay of lipase activity in a biological sample.

A new approach for the determination of lipase (triacylglycerol lipase, EC.3.1.1.3) activity in a biological sample was investigated by combining an immunocapture technique with a chemiluminescence (CL) assay method in order to eliminate interference with CL detection. The proposed method consists of an immunocapture step to trap lipase and a subsequent step for CL detection of the activity of the captured lipase. The CL detection is based on the luminol-hydrogen peroxide (H(2)O(2))-horseradish peroxidase (HRP) reaction and utilizes a proenhancer substrate [a lauric acid ester of 2-(4-hydroxyphenyl)-4,5-diphenylimidazole (HDI)] which liberates an active enhancer, HDI, by enzymatic hydrolysis. A polyclonal antibody prepared with porcine pancreas lipase was used for the immunocapture. The proposed immunocapture-CL method effectively eliminated the interference with the CL reaction from biological components and enabled the determination of spiked porcine pancreas lipase activity in serum samples in the range 0.41-1.1 U(HDI) (1 U(HDI) corresponds to the amount which liberates 1 pmol HDI/min at 37 degrees C from the substrate). The method was further applied to the assay of the activity for human pancreas lipase in serum and the results showed good correlation (r = 0.871) with those by the conventional colorimetric method.     

Novel emission properties of melem caused by the heavy metal effect of lanthanides(III) in a LB film.

A novel emissive molecular system is constructed by the intercalation of the fluorophore melem (triamino-tri-s-triazine) within a Langmuir-Blodgett (LB) film of stearic acid with the periodic arrangement of lanthanides (Ln(III)), mainly Pr(III) with supporting of Eu(III). From emission spectra, decay curves, quantum yields and XPS measurements, it is clarified that the external heavy metal effect of Pr(III) on melem is much stronger in the film than in the bulk solid state, resulting in producing an unusual triplet state of melem. The triplet state of melem in the LB film donates the excitation energy to Pr(III) in the LB film, which is completely different from the energy transfer pathway of Pr-melem complex in the solid state through the singlet state of melem.     

Enhancement of growth and cellulose accumulation by overexpression of xyloglucanase in poplar

Because the loosening of xyloglucan in the cell wall promotes plant growth (Takeda et al. (2002) Proc. Natl. Acad. Sci. USA 99, 9055-9060; Park et al. (2003) Plant J. 33, 1099-1106), we expressed Aspergillus xyloglucanase constitutively in Populus alba. The expression increased the length of stem even in the presence of sucrose. Increased stem growth was accompanied by a decrease in Young's elastic modulus in the growth zone but an increased elasticity in mature tissue. The increased internode length corresponded to an increase in cellulose content as well as specific gravity, showing that the removal of xyloglucan might cause an increase in cellulose density in the secondary xylem.     

Gurmarin suppression of licking responses to sweetener-quinine mixtures in C57BL mice

Gurmarin (Gur) is a peptide that selectively suppresses responses of the chorda tympani nerve to sweet substances in rats and mice. In the present study, we examined the effect of Gur on behavioral responses to sweet substances in C57BL mice. To accomplish this, we developed a new short-term lick test and measured numbers of licks for 10 s for sweet substances mixed with quinine hydrochloride (QHCl) in water-deprived mice. Numbers of licks for sucrose mixed with 1 or 3 mM QHCl increased with increasing concentration of sucrose from 0.01 to 1.0 M. Oral infusion with 30 micro g/ml Gur produced significant decreases in responses to concentration series for sucrose mixed with 3 mM QHCl, whereas no such effect by Gur was observed in responses to QHCl alone or QHCl-mixed HCl, NaCl or monosodium glutamate. The Gur suppression of QHCl-mixed sucrose responses, which otherwise lasted for 2-3 h, rapidly returned to approximately 80% of control levels after oral infusion with beta-cyclodextrin. These results are comparable to neural data previously found in chorda tympani responses, and thereby provide further evidence for Gur as a sweet response inhibitor in C57BL mice. In the other aspect, our newly developed short-term test can also provide a tool for measurements of taste-guided behavioral responses to sweeteners.     

Elucidation of endemic neurodegenerative diseases--a commentary

Recent investigations of scrapie, Creutzfeldt-Jakob disease (CJD), and chronic wasting disease (CWD) clusters in Iceland, Slovakia and Colorado, respectively, have indicated that the soil in these regions is low in copper and higher in manganese, and it has been well-known that patients of ALS or Parkinson's disease were collectively found in the New Guinea and Papua islands, where the subterranean water (drinking water) contains much Al3+ and Mn2+ ions. Above facts suggest that these neurodegenerative diseases are closely related with the function of a metal ion. We have investigated the chemical functions of the metal ions in detail and established the unique mechanism of the oxygen activation by the transition metal ions such as iron and copper, and pointed out the notable difference in the mechanism among iron, aluminum and manganese ions. Based on these results, it has become apparent that the incorporation of Al(III) or Mn(II) in the cells induces the "iron-overload syndrome", which is mainly due to the difference in an oxygen activation mechanism between the iron ion and Al(III) or the Mn(II) ion. This syndrome highly promotes formation of hydrogen peroxide, and hydrogen peroxide thus produced can be a main factor to cause serious damages to DNA and proteins (oxidative stress), yielding a copper(II)- or manganese(II)-peptide complex and its peroxide adduct, which are the serious agents to induce the structural changes from the normal prion protein (PrP(c)) to abnormal disease-causing isoforms, PrP(Sc), or the formation of PrP 27-30 (abnormal cleavage at site 90 of the prion protein). It seems reasonable to consider that the essential origin for the transmissible spongiform encephalopathies (TSEs) should be the incorporation and accumulation of Al(III) and Mn(II) ions in the cells, and the sudden and explosive increase of scrapie and bovine spongiform encephalopathy (BSE) in the last decade may be partially due to "acid rain", because the acid rain makes Al(III) and Mn(II) ions soluble in the subterranean aquifers.     

Endurance treadmill training in rats alters CRH activity in the hypothalamic paraventricular nucleus at rest and during acute running according to its period

Running training on the treadmill increases the resting hypothalamic corticotropin-releasing hormone (CRH) content in rats, though is still unknown whether and how it occurs in the parvocellular region of the hypothalamic paraventricular nucleus (PVN) where is a predominant region of pituitary-adrenal activity and where CRH and arginine vasopressin (AVP) are colocalized. We thus aimed at examining whether treadmill training would alter the CRH and AVP mRNA levels in the PVN at rest and during acute running with different lengths of a training regime. Male Wistar rats were subjected to treadmill running (approximately 25 m/min, 60 minutes/day, 5 times/week) for training regimes of 0, 1, 2 or 4 weeks. All training regimes induced an adrenal hypertrophy. Plasma corticosterone levels before acute running increased with lengthening the training period. Four weeks of training produced a significant increase in the resting CRH, but not AVP, mRNA levels in the PVN though relatively shorter training regimes did not. Acute responses of lactate and ACTH release were reduced after 2 and 4 weeks of training, respectively. The responsive PVN CRH mRNA level to acute running decreased with 4 weeks of training but increased with relatively shorter training regimes. These results indicate that running training changes the PVN CRH biosynthetic activity with the regime lasting for 4 weeks, which follows adaptive changes in adrenal functions. Thus, running training-induced changes in hypothalamic CRH activity would originate from the PVN and be induced according to the training period.