Neutrophils and monocytes transport tumor cell antigens from the peritoneal cavity to secondary lymphoid tissues

Antigen-transporting cells take up pathogens, and then migrate from sites of inflammation to secondary lymphoid tissues to induce an immune response. Among antigen-transporting cells, dendritic cells (DCs) are believed to be the most potent and professional antigen-presenting cells that can stimulate naïve T cells. However, the cells that transport antigens, tumor cell antigens in particular, have not been clearly identified. In this study we have analyzed what types of cells transport tumor cell antigens to secondary lymphoid tissues. We show that neutrophils, monocytes and macrophages but not DCs engulf X-irradiated P388 leukemic cells after their injection into the peritoneal cavity, and that neutrophils and monocytes but not macrophages migrate to the parathymic lymph nodes (pLN), the blood, and then the spleen. The monocytes in the pLN comprise Gr-1⁻ and Gr-1⁺ ones, and some of these cells express CD11c. Overall, this study demonstrates that neutrophils and monocytes transport tumor cell antigens from the peritoneal cavity to secondary lymphoid tissues.     

Hypergravity and opioid-mediated pain suppression in rats

It is known that pain suppression in animals is induced by certain environmental stimulus. However, little is known about the effects of gravitational alteration on the nociceptive responses in rats. A recent study indicated that Fos protein expression was strongly induced in the vestibular-related brainstem regions of rats that were exposed to 2 G hypergravity (Gustave Dit Duflo et al., 2000). A number of studies indicate that Fos expression is induced in the brain by various kinds of stress. We showed that either long-term exposure or short-term exposure to 2 G hypergravity elevated the nociceptive threshold in the rat skin surfaces, in concomitant with Fos induction in the hypothalamus including the arcuate nucleus and paraventricular nucleus (Kumei et al., 2000). We have examined the possible involvement of beta-endorphin, an endogenous opioid, in the hypergravity-induced analgesic effects on rats and its counteraction by naloxone, an opioid receptor antagonist.     

A novel mitochondrial carnitine-acylcarnitine translocase induced by partial hepatectomy and fasting

The carnitine-dependent transport of long-chain fatty acids is essential for fatty acid catabolism. In this system, the fatty acid moiety of acyl-CoA is transferred enzymatically to carnitine, and the resultant product, acylcarnitine, is imported into the mitochondrial matrix through a transporter named carnitine-acylcarnitine translocase (CACT). Here we report a novel mammalian protein homologous to CACT. The protein, designated as CACL (CACT-like), is localized to the mitochondria and has palmitoylcarnitine transporting activity. The tissue distribution of CACL is similar to that of CACT; both are expressed at a higher level in tissues using fatty acids as fuels, except in the brain, where only CACL is expressed. In addition, CACL is induced by partial hepatectomy or fasting. Thus, CACL may play an important role cooperatively with its homologue CACT in a stress-induced change of lipid metabolism, and may be specialized for the metabolism of a distinct class of fatty acids involved in brain function.     

The effect of fish oil on physical aggression in schoolchildren--a randomized, double-blind, placebo-controlled trial

OBJECTIVES: The aim of the study was to investigate whether fish oil supplementation affected Japanese schoolchildren's behavior, with changes in aggression over time as the primary endpoint. DESIGN AND SUBJECTS: A placebo-controlled double-blind study with 166 schoolchildren 9-12 years of age was performed. The subjects of the fish oil group (n=83) took fish oil-fortified foods (bread, sausage and spaghetti). These foods were provided in amounts such that each subject in the fish oil group had an intake of 3600 mg of docosahexaenoic acid+840 mg of eicosapentaenoic acid (EPA)/week for 3 months. The rest (the controls, n=83) took control supplements. At the start and end of the study, psychological tests were performed to assess their aggression. RESULTS: Physical aggression assessed by Hostility-Aggression Questionnaire for Children in girls increased significantly (median: 13 to 15, n=42) in the control group and did not change (13 to 13, n=43) in the fish oil group with a significant intergroup difference (P=.008) with baseline as covariate. The changes in physical aggression scores over time and those of the ratio of EPA/arachidonic acid in RBC (DeltaEPA/AA) were significantly correlated in girls who agreed to blood collection (r=-.53, P=.01, n=23). On the contrary, there were no significant changes in physical aggression in boys. Aggression against others (extraggression) assessed by Picture Frustration Study did not change in the control group (median: 5 to 5) but increased significantly in the fish oil group (4 to 5) with a significant intergroup difference (P=.02) with baseline as covariate. These changes in extraggression might be explained partly by significantly lower baseline values of extraggression in the fish oil group (P=.02) than in the control group. There were no significant correlations between Deltaextraggression and DeltaEPA/AA in blood-sampled children (n=49). Impulsivity of girls assessed by parents/guardians using the diagnostic criteria for attention deficit/hyperactivity disorder of DSM-IV was reduced in the fish oil group (1 to 0) with a significant (P=.008) intergroup difference from the control group (1 to 1). There were no significant correlations between Deltaimpulsivity and DeltaEPA/AA in blood-sampled girls. In males, impulsivity reduced in both groups without any intergroup differences. CONCLUSION: There is a possibility that changes in fatty acid nutrition might affect physical aggression especially in girls.     

Seed dispersal and predation by Yakushima macaques, Macaca fuscata yakui, in a warm temperate forest of Yakushima Island, southern Japan

The relationships between fruit morphology and the foraging behavior of the Yakushima macaque, Macaca fuscata yakui were studied during a 9-month field study and series of laboratory experiments on Yakushima Island, southern Japan. These relationships may affect seed germination traits through seed dispersal. The macaques foraging behavior was observed in order to obtain data concerning the treatment of pulp and seeds. Seeds in feces and spat seeds were collected and analyzed. A linear discriminant analysis of the data led to the following results: (i) an increase in the relative flesh volume of a fruit was one of the potential factors which increased the probability of seed dispersal by the macaques; and (ii) seed size was an important parameter in relation to the type of seed dispersal (by defecation or spitting out). The germination test was conducted in a laboratory, then the germination rates and delays of dispersed seeds were compared with those of seeds collected directly from trees. The germination of dispersed seeds of Ficus thunbergii, Eurya japonica, and Vaccinium bracteatum, was significantly enhanced by passage through the macaques gut. The enhanced germination behavior was not seen in larger seeds, such as those of Psychotria serpens, Myrsine seguinii, Diospyros morrisiana, and Neolitsea sericea. The germination enhancement in small-seeded plants could be due to a sorting effect from the passage through the gut, which selects seeds with a narrower range of germination traits.     

Analysis of oxidation sensitivity of maleate cis-trans isomerase from Serratia marcescens

The maleate cis-trans isomerase gene (maiA) from Serratia marcescens IFO3736 was cloned and sequenced. Serratia MaiA has 62.4% amino acid identity with Alcaligenes faecalis IFO13111 MaiA and 64.9% with Bacillus stearothermophilus MI-102 MaiA. All known ten amino acid sequences of MaiA had significant conserved regions containing cysteine residues, which were previously suggested to be involved in an active site of the enzyme. The maiA gene was expressed in Escherichia coli, and expressed products MaiA was purified and characterized. The purified enzyme of strain IFO3736 showed high activity at room temperature and high heat stability. It also showed higher activity in the presence of high concentration of aspartic acid than the enzyme of A. faecalis IFO13111, but it was also sensitive to chemical oxidation. By amino acid composition analysis, cysteine, methionine, and tyrosine residues were suggested to be oxidized to inactivate the enzyme by chemical oxidation. To investigate the mechanism of chemical oxidation of the enzyme, six methionine residues in the conserved regions of S. marcescens MaiA were replaced with cysteine residues by site-directed mutagenesis. The analysis of the constructed mutants suggested that the Met201 residue near the Cys198 residue is involved in the sensitivity of the enzyme to chemical oxidation.     

Molecular analysis of maleate cis-trans isomerase from thermophilic bacteria

Several strains of thermophilic bacteria containing maleate cis-trans isomerase were isolated from soil samples and identified as Bacillus stearothermophilus, Bacillus circulans, Bacillus brevis, and Deleya halophila. The maleate cis-trans isomerase was purified and characterized from one of the isolated strains, B. stearothermophilus MI-102. The purified enzyme of strain MI-102 showed higher thermal stability than the enzyme of a mesophile, Alcaligenes faecalis IFO13111. The seven maleate cis-trans isomerase genes (maiA) of thermophile were cloned and sequenced. B. stearothemophilus MI-102 MaiA has 67% amino acid identity with A. faecalis MaiA. All eight amino acid sequences of maiA gene products had significant conserved regions containing cysteine residues, which were previously suggested to be involved in an active site of the enzyme. To probe the catalytic mechanism, three cysteine residues in the conserved regions of A. faecalis MaiA were replaced with serine by site-directed mutagenesis. The results suggest that Cys80 and Cys198 play important roles in the enzyme activity.     

Identification and characterization of a second chromophore of DNA photolyase from Thermus thermophilus HB27

Cyclobutane pyrimidine dimer (CPD) photolyases use light to repair CPDs. For efficient light absorption, CPD photolyases use a second chromophore. We purified Thermus thermophilus CPD photolyase with its second chromophore. UV-visible absorption spectra, reverse-phase HPLC, and NMR analyses of the chromophores revealed that the second chromophore of the enzyme is flavin mononucleotide (FMN). To clarify the role of FMN in the CPD repair reaction, the enzyme without FMN (Enz-FMN(-) and that with a stoichiometric amount of FMN (Enz-FMN(+)) were both successfully obtained. The CPD repair activity of Enz-FMN(+) was higher than that of Enz-FMN(-), and the CPD repair activity ratio of Enz-FMN(+) and Enz-FMN(-) was dependent on the wavelength of light. These results suggest that FMN increases the light absorption efficiency of the enzyme. NMR analyses of Enz-FMN(+) and Enz-FMN(-) revealed that the binding mode of FMN is similar to that of 7,8-didemethyl-8-hydroxy-5-deazariboflavin in Anacystis nidulans CPD photolyase, and thus a direct electron transfer between FMN and CPD is not likely to occur. Based on these results, we concluded that FMN acts as a highly efficient light harvester that gathers light and transfers the energy to FAD.     

Effects of the frequency and duration of cyclic stress on the mechanical properties of cultured collagen fascicles from the rabbit patellar tendon

The effects of frequency or duration of cyclic stress on the mechanical properties of collagen fascicles were studied by means of in vitro tissue culture experiments. Collagen fascicles of approximately 300 microm in diameter were obtained from rabbit patellar tendons. During culture, cyclic stress having the peak stress of approximately 2 MPa was applied to the fascicles at 1 Hz for 1 hour/day (1 Hz-1 h group), at 1 Hz for 4 hours/day (1 Hz-4 h group), or at 4 Hz for 1 hour/day (4 Hz-1 h group). The frequency of 4 Hz and the duration of 1 hour/day are considered to be similar to those of the in vivo stress applied to fascicles in the intact rabbit patellar tendon. After culture for 1 or 2 weeks, the mechanical properties of the fascicles were determined using a microtensile tester, and were compared to the properties of non-cultured, fresh fascicles (control group) and the fascicles cultured under no load condition (non-loaded group). The tangent modulus and tensile strength of fascicles in the 4 Hz-1 h group were similar to those in the control group; however, the fascicles of the 1 Hz-1 h and 1 Hz-4 h groups had significantly lower values than those of the control group. There was no significant difference in the tensile strength between the 1 Hz-1 h and non-loaded groups, although the strength in the 1 Hz-4 h group was significantly higher than that of the non-loaded group. It was concluded that the frequency and duration of cyclic stress significantly affect the mechanical properties of cultured collagen fascicles. If we apply cyclic stress having the frequency and duration which are experienced in vivo, the biomechanical properties are maintained at control, normal level. Lower frequencies or less cycles of applied force induce adverse effects.