Potato extract (Potein) suppresses food intake in rats through inhibition of luminal trypsin activity and direct stimulation of cholecystokinin secretion from enteroendocrine cells

Dietary proteins and trypsin inhibitors are known to stimulate the secretion of the satiety hormone cholecystokinin (CCK). A potato extract (Potein) contains 60% carbohydrate and 20% protein including trypsin inhibitory proteins. In this study, we examined whether Potein suppresses food intake in rats and whether it directly stimulates CCK secretion in enteroendocrine cells. In fasted rats, food consumption was measured up to 6 h after the oral administration of Potein or soybean trypsin inhibitor (SBTI). CCK-releasing activities of Potein and SBTI were examined in the murine CCK-producing cell line STC-1. Potein inhibited the trypsin activity in vitro with a potency 20-fold lower than that of SBTI. Oral administration of Potein dose-dependently suppressed food intake for 1-6 h. Potein, but not the SBTI, dose-dependently induced CCK secretion in STC-1 cells. These results suggest that Potein suppresses food intake through the CCK secretion induced by direct stimulation on enteroendocrine cells and through inhibition of luminal trypsin.     

A comparison of different survey methods for assessing gap parameters in old-growth forests

Examining the actual state of canopy gaps in forests is critically important for evaluating forest community structure and dynamics, and for comparing gap disturbance regimes in different forests. We, therefore, re-examined our own previously published data from three studies of three different gap survey methods - the Belt transect method, the canopy coverage census method, and an aerial photography method - in order to ascertain how gap parameters (area, size and density of gaps, and related gap characteristics) obtained from these methods differ from each other. We found that the Belt transect method is easy to apply and practical in the field, and the method used for gap measurement is simple. Mean gap size and size distribution obtained using the Belt transect method were not different statistically from those of the other gap survey methods, and quantified gap parameters were in the range recorded for other forests of the world. For preliminary studies of gap dynamics in different forest types, an easy, speedy and workable gap survey method is needed. In addition, surveying a large number of gaps and a large area improve the accuracy of the method. We conclude that the Belt transect method is most suitable method for preliminary gap surveys in the field.     

Snapshot of activated G proteins at the membrane: the Galphaq-GRK2-Gbetagamma complex

G protein-coupled receptor kinase 2 (GRK2) plays a key role in the desensitization of G protein-coupled receptor signaling by phosphorylating activated heptahelical receptors and by sequestering heterotrimeric G proteins. We report the atomic structure of GRK2 in complex with Galphaq and Gbetagamma, in which the activated Galpha subunit of Gq is fully dissociated from Gbetagamma and dramatically reoriented from its position in the inactive Galphabetagamma heterotrimer. Galphaq forms an effector-like interaction with the GRK2 regulator of G protein signaling (RGS) homology domain that is distinct from and does not overlap with that used to bind RGS proteins such as RGS4.     

Growth characteristics,phytate contents,and coagulation properties of soymilk from a low-phytate Japanese soybean (Glycine max (L.) Merr.) line

The phytic acid (myo-inositol hexakisphosphate or InsP₆) content of seed crops is important to their nutritional quality. Since it represents 75?±?10% of the total seed phosphorus (P), phytic acid is also important regarding the management of P in agricultural production. A low-phytate F5 line, No. T-2-250-4-20, was selected from the progeny of a cross between the low-phytate soybean line CX1834 and the Japanese commercial cultivar Tanbakuro. This line and its parents were grown in a field nursery, and the growth characteristics, phytate accumulation, and processing suitability for tofu were evaluated. At full maturity, the weight of seeds per plant of line T-2-250-4-20 was 5.2- and 1.3-fold higher than that of CX1834 and Tanbakuro, respectively. The amount of phytate-phosphorus as a percentage of the total P content in seeds was 23% in line T-2-250-4-20-34, 30% in CX1834, and 69% in Tanbakuro. No significant difference was observed among the three cultivars/lines in their seed magnesium (Mg), potassium (K), crude protein, and sugar. However, the calcium (Ca), crude fat and ash contents in seeds of line T-2-250-4-20-34 and Tanbakuro was lowered compared to that of CX1834. The breaking stress of tofu was estimated employing a rheometer with a decreasing concentration of the coagulant magnesium chloride (MgCl₂), starting at 15.7?mmol?L^?1. In tofu made from Tanbakuro, the concentration of MgCl₂ required to achieve the maximum breaking stress was 12.6?mmol?L^?1; however, it was 9.5?mmol?L^?1 for tofu made from T-2-250-4-20-34 and CX1834. The tofu made from Tanbakuro was soft and broke at 6.3?mmol?L^?1 MgCl₂, but, in line T-2-250-4-20-34, harder tofu was made with lower MgCl₂ concentrations. No difference was observed among the cultivars/lines in the SDS-PAGE patterns of protein in soymilk. These results indicate that we have developed a low-phytate soybean with adequate productivity, and confirmed that tofu made from the low-phytate T-2-250-4-20-34 soybean becomes coagulated and harder at a lower MgCl₂ concentration than that from high-phytate soybean cultivars.     

Promoter analysis of two aromatase genes in the serial-sex changing gobiid fish, Trimma okinawae

Despite numerous endocrine studies on sex change in teleost, no general mechanism that mediates sex change has emerged. The gobiid fish, Trimma okinawae, can change sex in both directions repeatedly. This phenomenon of sex change in goby assigns it as an excellent animal model to elucidate the understanding mechanisms of sex change. In hermaphrodite fishes, estrogen plays a particularly important role in natural and experimentally induced sex change. To investigate the role of estrogen in the serial-sex changing fish T. okinawae, we cloned and analyzed the 5′-flanking regions of P450arom genes from goby genome DNA. Both regions have consensus sequences of TATA, CRE and ERE. Ad4 binding site was restricted in the region of P450aromA. These findings indicate that different regulators control the expression of the two P450arom genes.     

Non‐invasive sampling technique for DNA extraction from captive Japanese Crested Ibis on Sado Island

The Japanese Crested Ibis Nipponia nippon is a critically threatened bird. The post‐hatch eggs of the current captive population of this species on Sado Island have been stored at room temperature for the long‐term. In this study, we investigated the suitability of the vascularized chorioallantois membrane from the eggs as a non‐invasive DNA source. Using microsatellite loci developed for the Japanese Crested Ibis, we performed three experiments for comparison of genotypes obtained among DNA. First, DNA from five different sites of the identical membrane showed the same genotypes at either of two loci examined. Second, DNA from the membrane of each full‐sibling birds and blood of their parents showed the genotypes that were consistent with Mendelian parent–offspring relationships at any of eight loci examined. Third, DNA from the membrane and blood of the same bird showed the matched genotypes at any of eight loci examined. These results indicate that the vascularized chorioallantois membrane from post‐hatch eggs stored at room temperature for the long‐ term can be used as a reliable DNA source of offspring that had hatched from the egg. This study will promote a molecular genetics study on genetic diversity of the current captive Japanese Crested Ibis population on Sado Island.     

Determination of true absorption and fecal endogenous loss of zinc in goats

We determined the true absorption and endogenous fecal loss of zinc (Zn) in goats using its stable isotope. Three goats were fed with the diet containing 50 mg/kg Zn twice a day for 17 days. In the morning of day 11, the goats were given a meal labeled by ⁶⁷Zn as the tracer with dysprosium as the unabsorbed marker. Then the goats were given unlabeled diet as the rest of the morning feed. We measured dietary and fecal Zn concentration, ⁶⁷Zn abundance and dysprosium concentration in feces. The excretion pattern of the tracer Zn into feces differed from that of dysprosium. Therefore, we directly calculated the true absorption of Zn from Zn concentration and ⁶⁷Zn abundance in fecal samples collected after the labeled diet was given. The apparent absorption of Zn was –0.009 ± 0.016 mg/kg bodyweight (fractional absorption, ?1.07 ± 1.85%). The true absorption of Zn was 0.162 ± 0.018 mg/kg bodyweight (fractional absorption, 18.25 ± 2.01%). The endogenous fecal loss of Zn was 0.172 ± 0.004 mg/kg bodyweight and the intestinal secretion of Zn was 0.210 ± 0.009 mg/kg bodyweight. The present experiment indicates that stable isotopic Zn is a powerful tool for examining Zn metabolism in ruminants.     

Population dynamics and pathogenic races of rice blast fungus, <Emphasis Type="Italic">Magnaporthe oryzae</Emphasis> in the Mekong Delta in Vietnam

In a study of the population dynamics of Magnaporthe oryzae in the Mekong Delta in Vietnam, 226 isolates were collected from various sites in December 2001, September and December 2004. The pathogenic races of isolates were determined using international differential rice varieties. Isolates with the same race number were not found, not even in the same field or on the same seedling, suggesting that the fungus in the Mekong Delta was dynamically changing. But focusing on the known major resistance genes in the Japanese differential varieties, some isolates in the area were found to be the same race. Phylogenetic analyses based on the transposable elements Pot2 and MGR586 in the genomes supported that the pathogenic races were critically variable in comparison with the genomic diversity. Isolates with MAT1-1 predominated in the Mekong Delta, but in some provinces those with MAT1-2 coexisted at low frequency with MAT1-1. However, no isolates produced perithecia and ascospores. Isolates in the Mekong Delta probably had hot spots in their genomes that are easily altered and associated with some avirulence genes.     

Beech regeneration research: From ecological to silvicultural aspects

This review describes key regeneration characteristics of the genus Fagus as represented by its four most prominent species: F. crenata (F.c.), F. grandifolia (F.g.), F. orientalis (F.o.) and F. sylvatica (F.s.). Similarities and differences in the relevant life phases of these species are identified. Those are related to natural disturbance regimes and synecological peculiarities of the forests where they grow, thereby establishing a basis for evaluating the likely outcome of different silvicultural measures.     

Brazilin from Caesalpinia sappan wood as an antiacne agent

In screening experiments for antiacne activity, methanolic and 50% ethanolic extracts of Caesalpinia sappan wood showed the most potent activity out of 28 species of plants extracts. These extracts showed inhibition of Propionibacterium acnes growth, lipase inhibitory activity, and antioxidant activity. In order to isolate the active compound from C. sappan, separation of the extract components was performed by column chromatography and preparative high-performance liquid chromatography (HPLC). Brazilin, protosappanin A, and sappanone B were isolated from methanolic extracts. Brazilin showed better antibacterial activity [minimum inhibitory concentration (MIC) = minimum bactericidal concentration (MBC) = 0.50 mg/ml] than protosappanin A (MIC = MBC = 1.00 mg/ml) and sappanone B (MIC = MBC > 2.00 mg/ml). The 50% inhibitory concentration (IC₅₀) for lipase inhibition was lowest for brazilin (6 μM), which showed strong inhibition compared with protosappanin A (100 μM) and chloramphenicol (677 μM, positive control). The antioxidant activity of brazilin (IC₅₀ 8.8 μM) was not significantly different from protosappanin A (9.1 μM) and (+)-catechin (10.2 μM). The antioxidant activity of brazilin and protosappanin A were higher than sappanone B (IC₅₀ 14.5 μM). Brazilin is considered to have suffi ciently potent activity for use as an antiacne agent.