Regulatory effect of amino acids on the pasting behavior of potato starch is attributable to its binding to the starch chain

The binding of an amino acid, glycine (Gly), alanine (Ala), epsilon-aminocaproic acid (-AC), monosodium glutamate (GluNa), or lysine (Lys), to starch was examined by a biomolecular interaction analyzer (IAsys). A starch sample (ATS) hydrolyzed to an extent of 1% hydrolysis rate with 15% sulfuric acid was used as a model starch for the binding examination. The reducing end of ATS was oxidized by the Somogyi reagent, and the conversion of the reducing end to the carboxyl group of ATS was confirmed by a carboxylic acid fluorescence labeling reagent. The oxidized ATS was immobilized to the amino group of a sensor cuvette by using water-soluble carbodiimide and N-hydroxysuccinimide through an amide bond. The IAsys examination showed that Gly, Ala, and epsilon-AC scarcely bound to the immobilized starch chains but that GluNa and Lys favorably bound with their increasing concentrations. The relative binding index (RBI) of each amino acid was defined by the ratio of the slope of the linear regression equation between the binding response and the concentration for each amino acid to that for Gly. Because the relationships between the RBI and the pasting characteristics (pasting temperature, peak viscosity, breakdown, and swelling index) could each be expressed by a linear regression equation with a high correlation coefficient, it is concluded that the regulation of the pasting behavior of starch with an amino acid is caused by binding of the amino acid to the starch chains.     

Efficient digestion and structural characteristics of cell walls of coffee beans

Screening of effective food-processing cellulase for digestion of cell walls of coffee beans was carried out, and the cellulase from Trichoderma sp. was selected. The digestion of the cell walls of green and roasted coffee beans was carried out by sequential procedures of alkali boiling (0.1 M Na2CO3 buffer, pH 10, and 0.1 M NaOH), cellulase digestion, autoclaving with 0.1 M NaOH, and cellulase redigestion. The total digestion yields were >95 and >96%, respectively. The cell walls became thin, and the final residues of the cell walls were easily broken into small pieces. The neutral sugar analysis of the digestion or the extract and the residues and the microscopy observations with staining with toluidine blue O, Yariv reagent, and calcofluor for the residue in each step were investigated. Four structures, the galactomannan-cellulose (center part), the membrane of the arabinogalactan protein, the cellulose-rich galactomannan layer, and the arabinogalactan protein-rich layers (outer part), were found in the cell walls.     

Effects of phosphorus and potassium deficiency treatment on roots secretion of wheat and rice seedlings

Abstract

Firstly, the secretion of sugars, protein and acid phosphatase from wheat and rice roots into surrounding medium under conditions of P and K deficiency stresses were studied. Secondly, Sephadex elution patterns of wheat root exudates labeled with ¹⁴C under N, P and K deficiency treatments were compared.

P deficiency treatment induced acid phosphatase activity in medium, in spite of the decrease in the secretion of total sugars and pro tein from roots into medium, whereas no such increase was observed in K deficiency stress.

Secretion of high molecular fraction of ¹⁴C compounds from roots was accelerated by P deficiency stress, probably being associated with the presence of phosphatase activity in the medium.

Activity of acid phosphatase secreted from P-deficient roots corresponded to nearly one half of the rate of P absorption by normal plant.     

Distinctive expression of a zinc-binding protein in rice callus grown in medium with high zinc concentration

We investigated the growth, contents of water-soluble protein and free amino acids of the callus of japonica rice (Oryza sativa L. cv. Nipponbare) cultured in liquid N6 medium containing a high concentration of zinc. Furthermore, we determined the N-terminal amino acid sequence of a Zn-binding protein expressed in large quantities in the callus. The addition of Zn stimulated the growth of the callus and increased the Zn concentration. The callus subjected to the high-Zn treatment (hereafter referred to as CHZn) contained a larger amount of soluble proteins and a smaller amount of free amino acids than the control callus. Zinc-binding proteins were separated by affinity chromatography. The SDS-PAGE pattern of these proteins showed a distinctive protein band of about 29 kDa. Especially, CHZn contained larger quantities of 29 kDa protein than the control callus. Twenty-seven N-terminal amino acids of the protein were sequenced as DYAPMTLTIVNNCPYPVWPGIQANSGH. Results of homology search to the amino acid sequences from the nr-aa database and the dbEST database suggested that this 29 kDa protein may be a novel zinc-binding protein and that the protein may regulate the concentration of free zinc in the cytoplasm of callus cells through its binding to zinc ions.     

Ant nestmate and non-nestmate discrimination by a chemosensory sensillum

In animal societies, chemical communication plays an important role in conflict and cooperation. For ants, cuticular hydrocarbon (CHC) blends produced by non-nestmates elicit overt aggression. We describe a sensory sensillum on the antennae of the carpenter ant Camponotus japonicus that functions in nestmate discrimination. This sensillum is multiporous and responds only to non-nestmate CHC blends. This suggests a role for a peripheral recognition mechanism in detecting colony-specific chemical signals.     

Malignant hyperthermia in a horse anesthetized with halothane

Ahealthy, 565-kg, 14-year-old Quarter Horse gelding, negative for equine protozoal myelitis on serum Western blot and for hyperkalemic periodic paralysis (HYPP) by polymerase chain reaction, was selected for use in an electrophysiology study performed under inhalation anesthesia. The study was performed by following the guidelines of an Animal Use and Care Committee Protocol of the University of California at Davis (UCD 8578). Anesthesia was induced with halothane delivered via a face-mask. The horse was intubated 17 minutes later with an orotracheal tube and anesthesia was maintained with halo-thane by using a semiclosed, large-animal breathing circuit. Although muscle relaxation was otherwise good, the horse's ears remained tensed in a caudal direction throughout the study     

Effect of Dietary Carotenoid on Egg Yolk Color and Singlet Oxygen Quenching Activity of Laying Hens

The effects of dietary carotenoids on egg yolk were investigated in this study. Forty Rhode Island Red (RR) and 40 Silky Fowl (SF) hens that were 60 weeks old were used. Hens of each breed were randomly divided into four dietary groups. One group was fed a basal diet (crude protein 17%, metabolizable energy 2800 kcal/kg) only, whereas the other groups received a specific additive, namely, paprika extract, marigold petal extract, or Paracoccus cell powder, in addition to the same basal diet. The color and carotenoid content of egg yolk and singlet oxygen quenching activity were measured after 4 weeks. The total carotenoid content, zeaxanthin content, and singlet oxygen quenching activity in the yolk differed significantly between breeds and between diets (two-way ANOVA). The lutein content in egg yolk was affected by breed and diet, as well as by the interaction between these two factors. Regarding the Roche Yolk Color Fan values, only the effect of diet was significant. In terms of objective egg yolk color, there was a significant difference in lightness and yellowness between breeds. The total carotenoid content was higher in SF than in RR in all the groups. Likewise, the levels of zeaxanthin and lutein in the yolk were higher in SF than in RR (P<0.05). The results of the present study suggest that dietary carotenoids are effective feed additives for laying hens, especially SF, to improve the color and singlet oxygen quenching activity of egg yolk.     

Hpa1 secretion via type III secretion system in <Emphasis Type="Italic">Xanthomonas oryzae</Emphasis> pv. <Emphasis Type="Italic">oryzae</Emphasis>

In many Gram-negative plant pathogenic bacteria the type III secretion system (TTSS), encoded by hrp genes, is essential for pathogenicity in the host and induction of a hypersensitive reaction (HR) in nonhost plants. The expression of hrp genes has been suggested to be repressed in complex media, whereas it is induced in planta and under certain in vitro conditions. We recently reported that XOM2 medium allows efficient hrp expression by Xanthomonas oryzae pv. oryzae. In this study, we investigated hrp-dependent secretion of proteins by the bacteria in vitro. Using modified XOM2, in which bovine serum albumin was added and the pH was lowered to 6.0, we detected at least 10 secreted proteins and identified one as Hpa1. This is the first evidence of protein secretion via TTSS in X. oryzae pv. oryzae.     

Complex apocrine carcinoma with dominant myoepithelial proliferation in a dog

A rare case of complex apocrine carcinoma displaying dominant myoepithelial proliferation developed in the right leg subcutis of a 10-year-old male dog. The major cell population consisted of diffusely proliferating p63-expressing neoplastic cells that were largely myoepithelial in origin co-expressing α-smooth muscle actin. A small portion of the cell population consisted of concomitant basal epithelial cells lacking α-smooth muscle actin expression. The minor population consisted of p63-negative apocrine gland cells that expressed cytokeratin 8. The myoepithelial cell population showed a rather stronger proliferation activity than did the apocrine epithelial population. Thus, this tumor might have been derived from basal epithelial cells characterized by more predominant myoepithelial differentiation than luminal apocrine epithelial differentiation.