Antennal mechanosensors mediate sex pheromone‐induced upwind orientation in the potato tuberworm moth

Males of the potato tuberworm moth Phthorimaea operculella (Lepidoptera: Gelechiidae) locate conspecific females by a series of short and straight flights, or ‘hops’. On the floor of a wind tunnel, P. operculella can change their heading angles in response to wind direction shift, suggesting that they detect wind direction and orient upwind when on the ground. It is unlikely that they navigate in wind by vision‐induced optomotor anemotaxis as in many flying moths. To investigate the mechanism of wind direction detection in this species, their orientation behaviour in response to pheromone pulses is observed in a wind tunnel. Intact male moths orient upwind even in complete darkness. After the flagellum of one antenna is amputated, male moths still successfully orient upwind. However, they fail to head upwind when the basal segments of both of their antennae are immobilized with glue. The ability to surge upwind is restored by removing the glue from the antennae. Thus, the results of the present study indicate that males of P. operculella orient upwind in response to mechanoreceptive cues from mechanosensory organs on their antennae. In Lepidoptera, two distinct anemotactic mechanisms of different sensory modalities appear to coexist: optomotor anemotaxis when airborne and the aim‐then‐shoot anemotactic system mediated by antennal mechanoreception when on the ground.     

1H-NMR spectroscopy of the glycoprotein-bound large carbohydrates from embryonal carcinoma cells

400 MHz NMR spectrum was recorded for the glycoprotein -bound large carbohydrates (embryoglycan) isolated from F9 embryonal carcinoma cells. Two intense signals at 4.13 ppm and 4.69 ppm were assigned to be H-4 of galactosyl residues substituted at C-3 and H-1 of G1cNAc beta 1----3, respectively. The result is consistent with the proposal that the fundamental building unit of the large glycan is G1cNAc beta 1----3Ga1 beta. Furthermore, the spectral data confirmed a conclusion obtained by glycosidase digestion that fucosyl residues are linked mostly to N-acetylglucosamine rather than galactose.     

Leucine stimulates the secretion of hepatocyte growth factor by hepatic stellate cells

Branched-chain amino acids (BCAAs) modulate various cellular functions, in addition to providing substrates for the production of proteins. In this study, we examined the effect of BCAAs on the secretion of hepatocyte growth factor (HGF) by hepatic stellate cells. A hepatic stellate cell clone was cultured in medium supplemented with various concentrations of valine, leucine, or isoleucine. Of these BCAAs, leucine markedly induced an increase in the levels of HGF in the medium in a dose-dependent manner. The addition of valine or isoleucine had no significant effect on HGF levels in the medium. The difference in levels of HGF in the medium between leucine-treated and non-treated cells was enhanced by the incubation period. These results demonstrate that, among BCAAs, leucine stimulates the secretion of HGF by cultured hepatic stellate cells.     

The herbal medicine inchin-ko-to (TJ-135) induces apoptosis in cultured rat hepatic stellate cells

Use of herbal remedies in the treatment of various diseases has a long tradition in Eastern medicine and the liver diseases are not an exception. In their use, lack of elucidation of mechanism(s) as well as randomized, placebo-controlled clinical trials has been a problem. Recently, we and others reported that inchin-ko-to (TJ-135), one of herbal remedies, suppressed hepatic fibrosis in animal models. In the course of clarifying the mechanism, we directed our focus on hepatic stellate cells (HSCs), playing a pivotal role in hepatic fibrosis, and found that rat HSCs cultured with TJ-135 changed their morphology to star-like configuration with thin, slender and dendritic processes with fewer stress fibers, which might be the features in apoptosis. In fact, TJ-135 induced HSC apoptosis in a time- and concentration-dependent manner as judged by the nuclear morphology, quantitation of cytoplasmic histone-associated DNA oligonucleosome fragments and caspase 3 activity. In HSCs treated with TJ-135, increased expression of p53 and decreased expression of Bcl-2 and phosphorylated Akt and Bad were determined. HSC apoptosis is shown to be involved in the mechanisms of spontaneous resolution of rat hepatic fibrosis and the agent which induces HSC apoptosis has been shown to reduce experimental hepatic fibrosis in rats. Thus, the induction of HSC apoptosis could be the mechanism how TJ-135 works on the resolution of hepatic fibrosis. Our current data may shed light on the novel effect of the herbal remedy.     

Synthesis of a New Series of Z-Amino Acid and Z-Dipeptide Chloromethyl Ketone Derivatives

The synthesis of a new series of N^α-benzyloxycarbonyl (Z)-amino acid and Z-dipeptide chloromethyl ketone derivatives is described. The new derivatives are as follows; Z-l-Leu-CH₂Cl, Z-l-Phe (N0₂)-CH₂Cl, Z-l-Tyr (Bzl)-CH₂Cl, Z-l-Tyr (Z)-CH₂Cl, Z-l-Tyr-CH₂Cl, Z-l-Glu (Me)-CH₂Cl, Z-l-Phe-l-Leu-CH₂Cl, Z-l-Tyr-l-Leu-CH₃Cl, Z-l-Leu-l-Phe-CH₂Cl, Z-l-Leu-l-Tyr-CH₂Cl, Z-l-G1U (Me)-l-Tyr-CH₂Cl, Z-l-G1U (Me)-l-Phe-CH₂Cl.     

The role of Deinococcus radiodurans RecFOR proteins in homologous recombination

Deinococcus radiodurans exhibits extraordinary resistance to the lethal effect of DNA-damaging agents, a characteristic attributed to its highly proficient DNA repair capacity. Although the D. radiodurans genome is clearly devoid of recBC and addAB counterparts as RecA mediators, the genome possesses all genes associated with the RecFOR pathway. In an effort to gain insights into the role of D. radiodurans RecFOR proteins in homologous recombination, we generated recF, recO and recR disruptant strains and characterized the disruption effects. All the disruptant strains exhibited delayed growth relative to the wild-type, indicating that the RecF, RecO and RecR proteins play an important role in cell growth under normal growth conditions. A slight reduction in transformation efficiency was observed in the recF and recO disruptant strains compared to the wild-type strain. Interestingly, disruption of recR resulted in severe reduction of the transformation efficiency. On the other hand, the recF disruptant strain was the most sensitive phenotype to γ rays, UV irradiation and mitomycin C among the three disruptants. In the recF disruptant strain, the intracellular level of the LexA1 protein did not decrease following γ irradiation, suggesting that a large amount of the RecA protein remains inactive despite being induced. These results demonstrate that the RecF protein plays a crucial role in the homologous recombination repair process by facilitating RecA activation in D. radiodurans. Thus, the RecF and RecR proteins are involved in the RecA activation and the stability of incoming DNA, respectively, during RecA-mediated homologous recombination processes that initiated the ESDSA pathway in D. radiodurans. Possible mechanisms that involve the RecFOR complex in homologous intermolecular recombination and homologous recombination repair processes are also discussed.     

Structural analyses of asparagine-linked oligosaccharides of porcine pancreatic kallikrein

The structures of asparagine-linked oligosaccharides of porcine pancreatic beta-kallikrein are reported. Asparagine-linked neutral oligosaccharides were released by N-oligosaccharide glycopeptidase digestion, and the reducing ends of the oligosaccharides were derivatized with a fluorescent reagent, 2-aminopyridine. The mixture of pyridylamino oligosaccharides was separated by reverse-phase and amide-adsorption high-performance liquid chromatography. The pyridylamino oligosaccharides were separated into more than 50 kinds of oligosaccharides. The structures of 5 kinds of triantennary and 12 kinds of tetraantennary oligosaccharides were determined by the use of high-resolution proton nuclear magnetic resonance spectroscopy and methylation analysis. Furthermore, the structures of five kinds of oligomannose-type oligosaccharides were elucidated by a combination of exoglycosidase digestion and high-performance liquid chromatography. 1H NMR data for 14 out of the 17 kinds of N-acetyllactosamine-type oligosaccharides reported here have not previously been described in the literature. (1) It has been shown that fucose containing tri- and tetraantennary oligosaccharides is predominant in porcine pancreatic beta-kallikrein B. (2) It has also been shown that the heterogeneity of the structure in these types of oligosaccharides is derived from the variety of the positions of galactose residues linked to outer N-acetylglucosamine residues. (3) The distribution of oligosaccharides into two glycosylation sites, asparagine-95 and asparagine-239, of beta-kallikrein B was determined. It has been found that oligomannose-type oligosaccharides are exclusively present at asparagine-239, although N-acetyllactosamine-type oligosaccharides occur at both glycosylation sites.(ABSTRACT TRUNCATED AT 250 WORDS)     

Studies on lipase from Mucor javanicus. I. Purification and properties.

1. Lipase produced by a mold, Mucor javanicus, was purified about 180-fold from the ethanol precipitate of the culture filtrate. Purification was achieved by acid precipitation followed by gel filtrations on Sephadex G-200 (at low ionic strength) and Sephadex G-75 (at a high ionic strength). The purified enzyme preparation showed unusual behavior on polyacrylamide gel electrophoresis. The molecular weight was estimated to be 21 000. The enzyme had a positional specificity towards the position 1 and 3 of triacylglycerols. 2. Lipase in the crude preparation takes an aggregated form. aggregated form was achieved by raising the ionic strength of the medium. 3. The purified lipase preparation from Mucor javanicus exhibits phospholipase A1 activity, hydrolyzing the carboxyl ester at the 1-position of phosphatidylcholine. This activity seems to be due to the action of the lipase itself and not due to any other specific phospholipases.     

Characterization of N-type and dually permissive cells segregated from mouse fibroblasts whose Fv-1 phenotype could be modified by another independently segregating gene(s).

Though the inbred DDD mouse strain is essentially of the N type, the primary culture of this strain was about 100-fold more sensitive to B-tropic WN1802B virus than were the typical N-type strains (C3H/He, C57L, etc.). After cloning, DDD mouse cells segregated two types of cells, typical N-type cells and cells lacking in Fv-1 restriction. As both types of cells so far tested retained glucose-6-phosphatase-1 coded by a locus closely linked to Fv-1 and genetic cross experiments indicated the presence of a gene(s) modifying the Fv-1 phenotype, variation in Fv-1 restriction could presumably be brought about by genetic changes in a gene(s) other than Fv-1 itself. N-type and dually permissive cell clones were similarly established from the inbred G mouse. Compositions of polypeptides labeled with [35S]methionine in the N-type and dually permissive cells of DDD and G mouse origins were compared by two-dimensional gel electrophoresis. The polypeptide maps of these cells were similar except for a few spots. Among these dissimilar spots, a spot of about 20,000 daltons with a pI of about 5.5 was always present in N-type cells, whereas it was absent in dually permissive cells. In DDD mouse-derived clones, a proportional relation was observed between the intensity of the spot and the restriction to the B-tropic virus.