Enhancement of Cellulose Degradation by Cattle Saliva

Saccharification of cellulose is a promising technique for producing alternative source of energy. However, the efficiency of conversion of cellulose into soluble sugar using any currently available methodology is too low for industrial application. Many additives, such as surfactants, have been shown to enhance the efficiency of cellulose-to-sugar conversion. In this study, we have examined first whether cattle saliva, as an additive, would enhance the cellulase-catalyzed hydrolysis of cellulose, and subsequently elucidated the mechanism by which cattle saliva enhanced this conversion. Although cattle saliva, by itself, did not degrade cellulose, it enhanced the cellulase-catalyzed degradation of cellulose. Thus, the amount of reducing sugar produced increased approximately 2.9-fold by the addition of cattle saliva. We also found that non-enzymatic proteins, which were present in cattle saliva, were responsible for causing the enhancement effect. Third, the mechanism of cattle saliva mediated enhancement of cellulase activity was probably similar to that of the canonical surfactants. Cattle saliva is available in large amounts easily and cheaply, and it can be used without further purification. Thus, cattle saliva could be a promising additive for efficient saccharification of cellulose on an industrial scale.     

Histopathology of Incontinence-Associated Skin Lesions: Inner Tissue Damage Due to Invasion of Proteolytic Enzymes and Bacteria in Macerated Rat Skin

A common complication in patients with incontinence is perineal skin lesions, which are recognized as a form of dermatitis. In these patients, perineal skin is exposed to digestive enzymes and intestinal bacterial flora, as well as excessive water. The relative contributions of digestive enzymes and intestinal bacterial flora to skin lesion formation have not been fully shown. This study was conducted to reveal the process of histopathological changes caused by proteases and bacterial inoculation in skin maceration. For skin maceration, agarose gel containing proteases was applied to the dorsal skin of male Sprague-Dawley rats for 4 h, followed by Pseudomonas aeruginosa inoculation for 30 min. Macroscopic changes, histological changes, bacterial distribution, inflammatory response, and keratinocyte proliferation and differentiation were examined. Proteases induced digestion in the prickle cell layer of the epidermis, and slight bleeding in the papillary dermis and around hair follicles in the macerated skin without macroscopic evidence of erosion. Bacterial inoculation of the skin macerated by proteolytic solution resulted in the formation of bacteria-rich clusters comprising numerous microorganisms and inflammatory cells within the papillary dermis, with remarkable tissue damage around the clusters. Tissue damage expanded by day 2. On day 3, the proliferative keratinocyte layer was elongated from the bulge region of the hair follicles. Application of proteases and P. aeruginosa induced skin lesion formation internally without macroscopic erosion of the overhydrated area, suggesting that the histopathology might be different from regular dermatitis. The healing process of this lesion is similar to transepidermal elimination.     

Intracellular Encoding of Spatiotemporal Guidance Cues in a Self-Organizing Signaling System for Chemotaxis in Dictyostelium Cells

Even in the absence of guidance cues, chemotactic cells are often spontaneously motile, which should accompany a spontaneous symmetry breaking inside the cells. A shallow chemoattractant gradient can induce these cells to move directionally without much change in cell morphology. As the gradient becomes steeper, the accuracy of chemotaxis increases. It is not clear how the steepness is expressed or encoded internally in the signaling network, which in turn coordinately activates the motile apparatus for chemotaxis. In Dictyostelium cells, self-organizing polarization activities in the signaling network have been reported. In this paper, we conducted a theoretical study of the response of this self-organizing system to guidance cues. Our analyses indicate that self-organizing systems respond sharply to a shallow external gradient by increasing the precision of polarity direction and modulating the frequency of self-polarization. We also show how the precision increase and frequency modulation are achieved. Our results indicate that self-organizing activity, independent of external cues, is the basis for the sensitive and robust response to shallow gradients. Finally, we show that the system can sense the direction of space-time waves of a stimulus, for which Dictyostelium cells exhibit chemotaxis in the developmental process.     

Heterogeneity of Rice Glutelin

Three forms of endopolygalacturonase from Saccharomyces fragilis (Kluyveromyces fragilis) were separated by a procedure including adsorption on Amberlite IRC-50, CM Sephadex C-50 column chromatography and repeated preparative disc electrophoresis. Each endo-PG was almost homogenoeus as judged by polyacrylamide gel electrofocusing and disc electrophoresis. The three enzyme were designated as enzymes I, II and III. Enzymes I and II were similar but enzyme HI different from I and II in isoelectric point. The three enzymes resembled one another in eznyme action on pectic acid and other properties. All the three enzymes showed macerating activity toward the potato and carrot tissues.     

n-Hexanal and Some Volatile Alcohols

Both α-tocopherol and a 1: 1.7 mixture of α-tocopherol and tocotrienols at a 0.2% dietary level significantly depressed the age-related increase in the systolic blood pressure of spontaneously hypertensive rats (SHRs) after 3 weeks of feeding. The aortic production of prostacyclin was increased 1.5 times both by α-tocopherol and a tocotrienol mixture, suggesting a possible relevance to their hypotensive effect. These vitamins did not influence the Δ6- and Δ5-desaturase activities of liver microsomes, but fatty acid profiles of the liver phospholipids predicted a reduction of linoleic acid desaturation. These effects were in general more clear with tocotrienols than with α-tocopherol. Platelet aggregation by 5 μM ADP remained uninfluenced. Thus, tocotrienols may have effects on various lipid parameters somewhat different from those of α-tocopherol.     

Screening and characterization of an inhibitory chemical specific to Arabidopsis gibberellin 2-oxidases

The hydroxylation of gibberellin (GA) at the 2-position is known as the major cause of inactivation of GAs, whose reaction is catalyzed by 2-oxoglutarate dependent dioxygenases, also termed GA 2-oxidases (GA2oxs). To block GA catabolism in plants, a few chemicals can be used. To obtain novel inhibitors specific to GA2oxs, we performed in vitro random screenings by using ³H-16,17-dihydro-GA₄ and recombinant Arabidopsis GA2ox2. As a result, one candidate, methyl 6-chloro-3H-1,2,3-benzodithiazole-4-carboxylate 2-oxide (CBTC), was selected from the screening, and was subjected to in-planta evaluations. CBTC promoted both the germination and elongation of Arabidopsis seedlings. This strongly suggests that CBTC inhibits GA2oxs in Arabidopsis with high specificity.     

Climatic and historical factors controlling horizontal and vertical distribution patterns of two sympatric beech species, Fagus crenata Blume and Fagus japonica Maxim., in eastern Japan

The Japanese Archipelago is unique when viewed in terms of beech flora, since two native species, Fagus crenata Blume and Fagus japonica Maxim., occur sympatrically there. In order to examine the most important environmental or historical factors restricting the geographical ranges of these beech species in eastern Japan (34–44°N and 137–143°E), horizontal and vertical distributions were comparatively examined in detail. The study used two kinds of data sets: (1) DS1, constructed by assembling data from literature, herbarium specimens, etc., and (2) DS2, based on a mesh vegetation database. The upper range limit was expected to be in equilibrium with the current climatic conditions for both species (correlated with temperature factors for F. crenata and with snow depth for F. japonica). The lower range limit was also expected to be in equilibrium with the present climatic condition for both species, but the importance of competition with evergreen trees was also suggested. Dispersal limitation and a topo-geological barrier (for F. japonica) were expected to strongly restrict the northern range limit. Under contrasting climatic conditions in winter (between the Pacific and the Sea of Japan sides in eastern Japan) the geographic ranges of the two beech species are differentiated because of a difference in tolerance to heavy snowfall. A range shift model that assumes a migration lag along a horizontal direction because of dispersal limitation can explain the observed distribution patterns of these beech species in relation to climatic change in the Quaternary.     

Interaction-based evaluation of the propensity for amyloid formation with cross-beta structure

In order to reveal the requirements for amino acid sequences prone to form amyloid fibrils, a novel prediction method based on the original structural model of amyloids was developed. As a working hypothesis, two fundamental conditions were introduced into the design of the present system for the evaluation of the propensity for amyloidogenicity. The first of these two conditions was to ensure that the hydrophobic and hydrogen-bonding interactions between residues on neighboring antiparallel beta-strands were formed along a fibril axis. The other condition was that the hydrophobic interacting residues appeared on both faces of the protofibril, which gave line-matching interactions. Most peptides with sequences exhibiting high scores, as evaluated by this method, were found to easily form amyloids with the aid of a turn-inducing structure designed as a connection of two beta-strands. On the other hand, peptides with low-scoring native sequences and those modified by an internal residue-residue exchange (the latter yielding a null score) did not lead to amyloid formation. These data demonstrated the validity of this method for the prediction of amyloid structures. Moreover, the present study provided support for the proposed model of the essential structure associated with the above working hypothesis. The predicted high-scoring regions were in good agreement with the putative amyloid core regions reported thus far.