Intracerebroventricularly administered oxytocin attenuated cortisol secretion, but not behavioral responses, during isolation in Holstein steers

In rodents, intracerebroventricular oxytocin administration attenuated hypothalamo-pituitary-adrenal (HPA) responses and anxiety behavior during stress. We examined the effects of intracerebroventricular injection of oxytocin on isolation-induced stress responses in cattle. In a methodological test, we determined the dosage of oxytocin applied in a main test which did not induce an increase in plasma cortisol concentration or stereotyped behaviors. In a main test, 5 steers aged from 199 to 250 days were assigned to the following three treatments randomly: T1, no isolation after injection of 200 microl of artificial cerebrospinal fluid (aCSF); T2, isolation after aCSF injection; and T3, isolation after 0.5 microg of oxytocin in 200 microl aCSF injection. The isolation was conducted by leaving the experimental steer alone in its stall for one hour while its peers were taken outside. In T2, the isolation induced a rapid increase in plasma cortisol concentration. The maximum %-changes from the pre-isolation value were significantly attenuated by oxytocin injection (T2 vs. T3, p<0.05). The isolation also induced an increase in the frequency (number of occurrences/1 hr isolation) of vocalizations and body orientation changes, and a decrease in the percentage of time spent lying and ruminating. The effect of oxytocin on these behavioral responses to isolation was not apparent. These results indicate that intracerebroventricularly injected oxytocin at low dose attenuated the cortisol response to isolation in steers while the effect on behavior was very small in this experimental condition.     

Effects of serotonin injected into the third ventricle on prolactin and growth hormone secretion in Holstein steers

In order to clarify the role of serotonin (5-HT) in the regulation of pituitary hormones, the effects of 5-HT injected into the third ventricle (3V) on prolactin (PRL) and growth hormone (GH) release were investigated in Holstein steers. A chronic cannula was implanted in 3V by stereotaxic surgery under general anesthesia. After sufficient recovery from surgery, 5-HT (0, 0.1, 1.0, 2.0 mg) was injected into via the cannula and blood samples were collected over 4 h. Plasma PRL and GH concentrations were determined by radioimmunoassay. PRL release was significantly stimulated by the injection of 5-HT. The increase in PRL was observed at 20 min after the injection at three doses and the highest dose (2.0 mg) was the most effective in stimulating PRL release. The injection of 5-HT into 3V, at all doses tested, did not alter GH release significantly. Our results suggest that 5-HT is involved in the regulation of PRL release partly through the hypothalamus in cattle.     

Pacific Ocean and Japan Sea ecotypes of Japanese beech (Fagus crenata) differ in photosystem responses to continuous high light

Two ecotypes of Japanese beech (Fagus crenata Blume), the Pacific Ocean type (PAO) and the Japan Sea type (JAS), show different responses to high solar irradiance. When PAO and JAS saplings were grown in continuous high-light (H), leaves of JAS became pale green. To elucidate this phenomenon, we investigated in vivo photochemistry based on pigment concentrations of Photosystem (PS) I and PS II and Western blot analysis. In JAS-H leaves, the amount of D1-protein decreased, resulting in decreases in the maximal quantum yield of PS II (F(v)/F(m)) and electron transport rate, whereas PAO-H leaves maintained high activities. The PS I photochemistry determined by measurement of P-700 photo-oxidation showed that the intersystem electron pool size was 1.4 times greater in JAS-H leaves than in PAO-H leaves. Furthermore, the re-reduction kinetics of P-700(+) showed that cyclic electron transport around PS I was 1.2 times faster in PAO-H leaves than in JAS-H leaves. Analysis of the area over the fluorescence induction kinetics indicated that the relative abundance of the PS IIalpha center increased in PAO-H leaves, whereas JAS leaves were observed to have low acclimation capacity to high light. These results demonstrate that PAO leaves possess acclimation mechanisms to continuous high light, whereas JAS leaves are more vulnerable to continuous high light, resulting in reduced leaf longevity owing to photoinhibition caused by increases in the intersystem electron pool size and suppression of photochemistry at the level of PS I and PS II.     

Structure-activity relationships of tea compounds against human cancer cells

The content of the biologically active amino acid theanine in 15 commercial black, green, specialty, and herbal tea leaves was determined as the 2,4-dinitrophenyltheanine derivative (DNP-theanine) by a validated HPLC method. To define relative anticarcinogenic potencies of tea compounds and teas, nine green tea catechins, three black tea theaflavins, and theanine as well as aqueous and 80% ethanol/water extracts of the same tea leaves were evaluated for their ability to induce cell death in human cancer and normal cells using a tetrazolium microculture (MTT) assay. Compared to untreated controls, most catechins, theaflavins, theanine, and all tea extracts reduced the numbers of the following human cancer cell lines: breast (MCF-7), colon (HT-29), hepatoma (liver) (HepG2), and prostate (PC-3) as well as normal human liver cells (Chang). The growth of normal human lung (HEL299) cells was not inhibited. The destruction of cancer cells was also observed visually by reverse phase microscopy. Statistical analysis of the data showed that (a) the anticarcinogenic effects of tea compounds and of tea leaf extracts varied widely and were concentration dependent over the ranges from 50 to 400 microg/mL of tea compound and from 50 to 400 microg/g of tea solids; (b) the different cancer cells varied in their susceptibilities to destruction; (c) 80% ethanol/water extracts with higher levels of flavonoids determined by HPLC were in most cases more active than the corresponding water extracts; and (d) flavonoid levels of the teas did not directly correlate with anticarcinogenic activities. The findings extend related observations on the anticarcinogenic potential of tea ingredients and suggest that consumers may benefit more by drinking both green and black teas.     

Pole and global shape of 25143 Itokawa

The locations of the pole and rotation axis of asteroid 25143 Itokawa were derived from Asteroid Multiband Imaging Camera data on the Hayabusa spacecraft. The retrograde pole orientation had a right ascension of 90.53 degrees and a declination of -66.30 degrees (52000 equinox) or equivalently 128.5 degrees and -89.66 degrees in ecliptic coordinates with a 3.9 degrees margin of error. The surface area is 0.393 square kilometers, the volume is 0.018378 cubic kilometers with a 5% margin of error, and the three axis lengths are 535 meters by 294 meters by 209 meters. The global Itokawa revealed a boomerang-shaped appearance composed of two distinct parts with partly faceted regions and a constricted ring structure.     

Cinnamaldehyde content in foods determined by gas chromatography-mass spectrometry

trans-Cinnamaldehyde, the principal component of cinnamon flavor, is a potent antimicrobial compound present in essential oils such as cinnamon. In the course of studies designed to discover its maximum microbial lethality under food-processing conditions, a gas chromatographic-mass spectrophotometric procedure was developed for the extraction and analysis of essential oil components such as cinnamaldehyde from commercial cinnamon-containing foods (several brands of cinnamon breads, cereals, cookies, puddings, applesauces, and fruit juices). The cinnamaldehyde content ranged from trace amounts in orange juice to 12.2 mg/100 g (122 ppm) in apple cinnamon cereals and 31.1 mg/100 g (311 ppm) for cinnamon swirl bread (highest value). To ascertain the heat stability of cinnamaldehyde, pure cinnamaldehyde, pure eugenol, cinnamon oil, and mixtures consisting of cinnamaldehyde plus eugenol or cinnamon oil were heated at graded temperatures up to 210 degrees C and 60 min, and then possible compositional changes were examined. Eugenol was stable to heat, as were the components of cinnamon oil: carvone, eugenol, and linalool. In contrast, starting at approximately 60 degrees C, pure cinnamaldehyde undergoes a temperature-dependent transformation to benzaldehyde under the influence of heat. Eugenol, both pure and in cinnamon oil, when added to pure cinnamaldehyde protected the aldehyde against heat destruction. The protection may due to an antioxidative action of eugenol. The possible mechanism of this effect and the significance of these findings for food chemistry and microbiology are discussed.     

Distribution of free amino acids, flavonoids, total phenolics, and antioxidative activities of Jujube (Ziziphus jujuba) fruits and seeds harvested from plants grown in Korea

Fruit pulp and seeds from the jujube plant possess nutritional and medicinal properties. The bioactive components have been shown to vary both with cultivar and with growing conditions. Most studies report the components of varieties from China. We measured free amino acid, individual phenolic, and total phenolic content, and antioxidative activities in three jujube fruit pulp extracts from Boeun-deachu, Mechu, and Sanzoin cultivars and two seed extracts (Mechu and Sanzoin) from plants grown in Korea. In g/100 g dry weight, total free amino acid content measured by ion-exchange chromatography ranged from 5.2 to 9.8 in the pulp and from 4.0 to 5.3 in the seed. Total phenolic content measured by Folin-Ciocalteu ranged from 1.1 to 2.4 in the pulp and from 3.6 to 4.6 in the seed. Flavonoids were measured by HPLC and ranged from 0.7 to 1.8 in the pulp and from 3.2 to 4.0 in the seed. Flavonoids were identified by HPLC elution position and UV/vis and mass spectra. Fruits contained the following flavonoids: procyanidin B2, epicatechin, quercetin-3-O-rutinoside (Q-3-R), quercetin-3-O-galactoside (Q-3-G), kaempferol-glucosyl-rhamnoside (K-G-R), and two unidentified compounds. Seeds contained the following flavonoids: saponarin, spinosin, vitexin, swertish, 6'-hydroxybenzoylspinosin (6'-HBS), 6'-feruloylspinosin (6'-FS), and one unidentified substance. Dimensions and weights of the fresh fruit samples affected phenolic content. The distribution of the individual flavonoids among the different samples varied widely. Data determined by the FRAP antioxidative assay were well correlated with total phenolic content. In a departure from other studies, data from the DPPH free radical assay were not correlated with FRAP or with any of the measured compositional parameters. Because individual jujube flavonoids are reported to exhibit different health-promoting effects, knowledge of the composition and concentration of bioactive compounds of jujube products can benefit consumers.     

Isolation of Staphylococcus aureus from raw fish in relation to culture methods

Five hundred and fifty fish samples from various stages in the course of distribution in Hyogo Prefecture (209 retailed in super markets, 173 obtained from fishery cooperatives at a harbor, 91 caught by trawling and 77 caught by rod fishing) were examined for contamination with Staphylococcus aureus (S. aureus). S. aureus was detected in 41 (19.6%) of the retail fish samples and 46 (26.6%) of the samples from the fishery cooperatives. No S. aureus was isolated from the live fish (91 trawled and 77 fished by rod). With regard to the retail fish, the contamination rate of processed fish (26.0%) was significantly higher than that of unprocessed fish (14.2%). For 88 samples, the efficacy of the selective medium was compared using Baird-Parker agar and mannitol salt agar supplemented with egg yolk (MSEY agar) by the direct plate and enrichment culture methods. Using the direct culture method, the S. aureus positive rate with the Baird-Parker agar (30.7%) was significantly higher (P<0.01) than that with the MSEY agar (6.8%). The enrichment culture method remarkably raised the S. aureus detection rate. Seventy-eight (85.7%) of 91 isolates belonged to the human ecovar. Sixty-two (68.1%) of the 91 isolates had some enterotoxin genes, including 44 (48.4%) with the sea gene. These data showed that the fish were contaminated with S. aureus after landing and that Baird-Parker agar had an advantage in detecting S. aureus with a direct plate culture.     

Effects of intravenous tryptophan infusion on thermoregulation in steers exposed to acute heat stress

This study was conducted to investigate the effect of tryptophan (TRP) supply on the thermoregulatory responses via brain serotonin (5‐HT) in cattle. In period 1, 12 Holstein steers were kept under a constant room temperature (22°C) and were administered the intravenous (i.v.) infusion of saline or TRP (38.5 mg/kg/2 h). Changes in rectal temperature (RT), 5‐HT concentration in the cerebrospinal fluid (CSF), and other factors involved in thermoregulation were measured. In period 2, the steers received the same treatments as in period 1; however, the room temperature was elevated from 22°C to 33°C during i.v. infusion and maintained at 33°C for 3 h. 5‐HT concentration in CSF increased following TRP infusion in both periods, and RT significantly decreased following TRP infusion only in period 2. The effect of TRP on respiration rate and plasma prolactin and total triiodothyronine concentrations was not significant. These results suggest that increase in TRP supply can attenuate increase in RT in response to acute heat stress through the increase in brain 5‐HT, followed by presumable increase in evaporative heat loss from the skin surface in cattle. It is possible that the increase in peripheral blood TRP metabolites could also participate in the hypothermic effect of TRP.     

Intravenous tryptophan administration attenuates cortisol secretion induced by intracerebroventricular injection of noradrenaline

This study was conducted to investigate the possibility of suppression of stress‐induced cortisol (CORT) secretion by tryptophan (TRP) administration and to better understand its regulatory mechanisms by using a noradrenaline (NA) injection into the third ventricle (3V) as a stress model in cattle. A total of 25 Holstein steers with a cannula in the 3V were used. First, the increase in CORT secretion was observed following a NA injection into the 3V in a dose‐dependent manner, verifying the appropriateness of this treatment as a stress model of CORT secretion (Experiment 1). The effect of prior‐administration of TRP into peripheral blood with a dose that has been demonstrated to increase brain 5‐hydroxytryptamine levels on the elevation of plasma CORT induced by NA or corticotropin‐releasing hormone (CRH) was then examined (Experiment 2). The prior administration of TRP suppressed NA‐induced, but not CRH‐induced, CORT elevation. These results suggest that an increase in TRP absorption into peripheral blood could suppress the stress‐induced CORT secretion in cattle via the attenuation of the stimulatory effect of NA on the hypothalamic CRH release.