In vitro reduction of manganese dioxide by a ferrireductase system from the white-rot fungus <Emphasis Type="Italic">Phanerochaete sordida</Emphasis> YK-624

Reduction of manganese dioxide is demonstrated for an in vitro ferrireductase system that includes NADPH-dependent ferrireductase and the iron-binding compound (IBC) isolated from the white-rot fungus Phanerochaete sordida YK-624. The Fe(II)–IBC complex was more effective in reducing manganese dioxide to Mn(II) than were complexes of Fe(II) and organic acids of low molecular weight such as nitrilotriacetate, although IBC also reduced manganese dioxide to Mn(II) in the absence of Fe(II). The generated Fe(III)–IBC complex was a better substrate for NADPH-dependent ferrireductase than were other ferric chelates, suggesting that the Fe(III)–IBC complex is reduced to an Fe(II) complex by NADPH-dependent ferrireductase. Moreover, production of the Fe(III)–IBC complex by the reduction of manganese dioxide in a reaction system containing Fe(II) and IBC was observed to be coupled to reduction of the Fe(III)–IBC complex by NADPH-dependent ferrireductase. These results indicate that the ferrireductase system of P. sordida YK-624 plays an important role in the reduction of manganese dioxide, which is necessary for the production and function of manganese peroxidase.     

In vitro screening of angiotensin I-converting enzyme inhibitors from Japanese cedar (Cryptomeria japonica)

Screening and isolation of angiotensin I-converting enzyme (ACE) inhibitors from Japanese cedar (Cryptomeria japonica) based on the in vitro ACE inhibitory assay were attempted. The ethanol extract from outer bark showed the highest inhibitory activity (IC₅₀ is 16g/ml) among 24 extracts prepared from roots, leaves, heartwood, sapwood, inner bark, and outer bark by successive extraction with four solvents. The fractionation of the outer bark ethanol extract followed by the bioassay resulted in the isolation of two strong ACE inhibitors, catechin and dimeric procyanidin B3. The bioassay of three flavan-3-ols including (+)-catechin and six flavones revealed that most of these compounds have high ACE inhibitory activity. The results suggest that the phenolic hydroxyl group at the C7 position and heterocyclic oxygen atom of these compounds are important for expressing the inhibitory activity.     

Structural changes of residual lignin in softwood kraft pulp treated with manganese peroxidase

Structural changes of residual lignin in unbleached softwood kraft pulp (SWKP) during manganese peroxidase (MnP) treatment were investigated to obtain some understanding of the biobleaching action of SWKP with MnP treatment. Alkaline-extracted lignin from darkened SWKP by MnP showed more intense color and contained moreo-quinone than that from control SWKP. However, no difference in the conjugated-carbonyl was observed between the lignins from MnP-treated and control SWKP. The nitrobenzene oxidation analysis revealed that oxidative condensation of non-condensed lignin in SWKP occurs during an early stage of MnP treatment. These observations were supported by the model experiment in which the lignin prepared from control SWKP was subjected to MnP treatments three times, and the changes of color and functional groups in the lignin were determined after each treatment. These results suggested that an increase ino-quinone and the condensation reaction of non-condensed lignin in SWKP are responsible for the characteristic darkening of SWKP during MnP treatment. It was also ascertained that darkened lignin was degraded and brightened by repeated MnP treatments.     

Polyethylene degradation by lignin-degrading fungi and manganese peroxidase

Degradation of high-molecular-weight polyethylene membrane by lignin-degrading fungi, IZU-154, Phanerochaete chrysosporium, and Trametes versicolor, was investigated under various nutritional conditions. IZU-154 showed the most significant polyethylene degradation among the three lignin-degrading fungi under nitrogen- or carbon-limited culture conditions. Furthermore, for T. versicolor and P. chrysosporium, the addition of Mn(II) into nitrogen- or carbon-limited culture medium enhanced polyethylene degradation. These results suggest that polyethylene degradation is related to ligninolytic activity of lignin-degrading fungi. Treatment of polyethylene membrane with partially purified manganese peroxidase (MnP) caused significant degradation in the presence of Tween 80, Mn(II), and Mn(III) chelator. This result demonstrates that MnP is the key enzyme in polyethylene degradation by lignin-degrading fungi.This study was presented in part at the 9th International Symposium on Wood and Pulping Chemistry, Montreal, Canada, June 9–12, 1997     

Myricanol and myricanone biosynthesis in <Emphasis Type="Italic">Myrica rubra</Emphasis>: incorporation of two molecules of 4-coumaric acid

After feeding experiments of Myrica rubra young shoots with 4-[8,9-¹³C₂]coumaric acid, mass spectrometric analyses revealed that the cyclic diarylheptanoids, myricanol and myricanone, were derived from two molecules of 4-coumaric acid. ¹³C Nuclear magnetic resonance analysis of myricanol isolated after administration of 4-[8,9-¹³C₂]coumaric acid demonstrated that the C-8 and C-9 atoms of 4-coumaric acid are incorporated into C-8, C-9, C-11, and C-12 of the corresponding myricanol. Part of this report was presented at the 56th Annual Meeting of the Japan Wood Research Society, Akita, August 2006     

Functions and structure of roots and their contributions to salinity tolerance in plants

Soil salinity is an increasing threat to the productivity of glycophytic crops worldwide. The root plays vital roles under various stress conditions, including salinity, as well as has diverse functions in non-stress soil environments. In this review, we focus on the essential functions of roots such as in ion homeostasis mediated by several different membrane transporters and signaling molecules under salinity stress and describe recent advances in the impacts of quantitative trait loci (QTLs) or genetic loci (and their causal genes, if applicable) on salinity tolerance. Furthermore, we introduce important literature for the development of barriers against the apoplastic flow of ions, including Na⁺, as well as for understanding the functions and components of the barrier structure under salinity stress.     

Effects of fertilization, crop year, variety, and provenance factors on mineral concentrations in onions

Mineral concentrations of onions (Allium cepa L.) grown under various conditions, including factors (fertilization, crop year, variety, and provenance), were investigated to clarify how much each factor contributes to the variation of their concentrations. This was because the mineral concentrations might be affected by various factors. The ultimate goal of this study was to develop a technique to determine the geographic origins of onions by mineral composition. Samples were onions grown under various conditions at 52 fields in 18 farms in Hokkaido, Japan. Twenty-six elements (Li, Na, Mg, Al, P, K, Ca, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Y, Mo, Cd, Cs, Ba, La, Ce, Nd, Gd, W, and Tl) in these samples were determined by inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry. Fertilization conditions and crop years of onions caused variations of P, Ni, Cu, Rb, Sr, Mo, Cs, and Tl concentrations in onions; different onion varieties also showed variations in numerous element concentrations. However, the variations of mineral compositions of onions by these factors were smaller than the differences between production places with a few exceptions. Furthermore, Na, Rb, and Cs in group IA of the periodic table, Ca, Sr, and Ba in group IIA, and Zn and Cd in group IIB showed similar concentration patterns by group; this result demonstrated that elements in the same periodic groups behaved similarly in terms of their absorption in onions.     

Prevalence of amyloid deposition in mature healthy chickens in the flock that previously had outbreaks of vaccine-associated amyloidosis

Avian amyloid A (AA) amyloidosis is commonly observed in adult birds with chronic inflammation, such as that caused by bacterial infection. We previously described vaccine-associated AA amyloidosis in juvenile chickens. In this study, the prevalence of amyloid deposition was measured in mature healthy chickens that survived a previous outbreak of avian AA amyloidosis while they were juveniles. Herein, we analyzed the amyloid deposition in mature chickens and compared the prevalence of amyloid deposition with juvenile chickens obtained in our previous study (Murakami et al., 2013). We found that: 1) amyloid deposition in the liver was absent in mature chickens, while juvenile chickens had a rate of 24%; 2) amyloid deposition in the spleen was observed in 36% of juvenile chickens and in 40% of mature chickens; 3) amyloid deposition in the pectoral muscle of mature chickens (43.75%) was approximately half that of juvenile chickens (88%). These results suggest that additional amyloid deposition in chickens previously exposed to AA amyloidosis may not worsen with age. Further, amyloid deposition in chickens may tend to regress when causative factors, such as vaccinations and/or chronic inflammation, are absent.     

Development of a programmable piggyback syringe pump and four-times-a-day injection regimen for superovulation in non-lactating Holstein cows

The objectives of the present study were to develop a programmable piggyback syringe pump for bovine superovulation and to evaluate the effects of a four-times-a-day injection regimen using the pump. Non-lactating Holstein cows were treated with a total of 30 armour units of porcine FSH by injection four times a day with the pump (study, n = 9) or injection twice a day manually (control, n = 9) for four consecutive days from D10 of the estrous cycle. The pump-driven program successfully induced superovulation in all cows tested. The numbers of small (3– < 5 mm in diameter) and large (≥ 10 mm in diameter) follicles were greater in the study group on D11-13 and D14, respectively. There were fewer unovulated follicles detected on D21 (7 days after estrus) in the study group than in the control group (1.2 ± 0.4 and 3.2 ± 0.6, respectively).     

Effects of saliva collection using cotton swabs on melatonin enzyme immunoassay

Background  

Although various acceptable and easy-to-use devices have been used for saliva collection, cotton swabs are among the most common ones. Previous studies reported that cotton swabs yield a lower level of melatonin detection. However, this statistical method is not adequate for detecting an agreement between cotton saliva collection and passive saliva collection, and a test for bias is needed. Furthermore, the effects of cotton swabs have not been examined at lower melatonin level, a level at which melatonin is used for assessment of circadian rhythms, namely dim light melatonin onset (DLMO). In the present study, we estimated the effect of cotton swabs on the results of salivary melatonin assay using the Bland-Altman plot at lower level.