Dispersion and oxidative stability of O/W emulsions and oxidation of microencapsulated oil

Oil-in-water (O/W) emulsions are among the dispersion systems commonly used in food, and these emulsions are in thermodynamically unstable or metastable states. In this paper, various methods for preparing O/W emulsions are outlined. Since the commodity value of food is impaired by the destabilization of O/W emulsions, experimental and theoretical approaches to assess the stability of O/W emulsions are overviewed, and factors affecting the dispersion stability of emulsions are discussed based on the DLVO theory and the concept of the stability factor. The oxidation of lipids in O/W emulsions is unhealthy and gives rise to unpleasant odors. Factors affecting the autoxidation of lipids are discussed, and theoretical models are used to demonstrate that a reduction of the oil droplet size suppresses or retards autoxidation. Microencapsulated lipids or oils exhibit distinct features in the oxidation process. Models that explain these features are described. It is demonstrated that a reduction in the oil droplet size is also effective for suppressing or retarding the oxidation of microencapsulated oils.     

A plant effector‐triggered immunity signaling sector is inhibited by pattern‐triggered immunity

Since signaling machineries for two modes of plant‐induced immunity, pattern‐triggered immunity (PTI) and effector‐triggered immunity (ETI), extensively overlap, PTI and ETI signaling likely interact. In an Arabidopsis quadruple mutant, in which four major sectors of the signaling network, jasmonate, ethylene, PAD4, and salicylate, are disabled, the hypersensitive response (HR) typical of ETI is abolished when the Pseudomonas syringae effector AvrRpt2 is bacterially delivered but is intact when AvrRpt2 is directly expressed in planta. These observations led us to discovery of a network‐buffered signaling mechanism that mediates HR signaling and is strongly inhibited by PTI signaling. We named this mechanism the ETI‐Mediating and PTI‐Inhibited Sector (EMPIS). The signaling kinetics of EMPIS explain apparently different plant genetic requirements for ETI triggered by different effectors without postulating different signaling machineries. The properties of EMPIS suggest that information about efficacy of the early immune response is fed back to the immune signaling network, modulating its activity and limiting the fitness cost of unnecessary immune responses.     

Intraspecific Sequence Variation of Chloroplast DNA Reflecting Variety and Geographical Distribution of <Emphasis Type="Italic">Polygonum cuspidatum</Emphasis> (Polygonaceae) in Japan

Polygonum cuspidatum in Japan, we analyzed the chloroplast DNA sequences of a region from the rbcL to the accD gene (ca. 1,420 bp), and found nucleotide variations at 22 sites in 68 samples. The phylogenetic relationship deduced from the sequence variations revealed the existence of at least five groups. The first group consisted of P. cuspidatum var. cuspidatum in the central part of Honshu; in Nagano, Yamanashi, and Shizuoka. The second, a sister of the first, consisted of those plants in Shizuoka-Itoigawa Line. The third group consisted of plants in the northern part of Japan including P. sachalinense in Hokkaido, P. cuspidatum var. cuspidatum in Aomori and var. uzensis in Akita. The fourth consisted of var. uzensis in the Tohoku District. The fifth consisted of var. terminalis in the Izu Islands. P. cuspidatum are differentiated according to their distribution, and two varieties, var. terminalis and var. uzensis, are differentiated genetically. Polygonum sachalinensis, a distinct species morphologically, fell into the accessions of P. cuspidatum on the phylogenetic tree obtained in the present study. Received 9 July 2000/ Accepted in revised form 11 October 2000     

Molecular database for classifying Shorea species (Dipterocarpaceae) and techniques for checking the legitimacy of timber and wood products

The extent of tropical forest has been declining, due to over-exploitation and illegal logging activities. Large quantities of unlawfully extracted timber and other wood products have been exported, mainly to developed countries. As part of the export monitoring effort, we have developed methods for extracting and analyzing DNA from wood products, such as veneers and sawn timbers made from dipterocarps, in order to identify the species from which they originated. We have also developed a chloroplast DNA database for classifying Shorea species, which are both ecologically and commercially important canopy tree species in the forests of Southeast Asia. We are able to determine the candidate species of wood samples, based on DNA sequences and anatomical data. The methods for analyzing DNA from dipterocarp wood products may have strong deterrent effects on international trade of illegitimate dipterocarp products. However, the method for analyzing DNA from wood is not perfect for all wood products and need for more improvement, especially for plywood sample. Consequently, there may be benefits for the conservation of tropical forests in Southeast Asia.     

Differential gene regulation by V(IV) and V (V) ions in the branchial sac, intestine, and blood cells of a vanadium-rich ascidian, Ciona intestinalis

Ascidians are hyperaccumulators that have been studied in detail. Proteins and genes involved in the accumulation process have been identified, but regulation of gene expression related to vanadium accumulation remains unknown. To gain insights into the regulation of gene expression by vanadium in a genome-wide manner, we performed a comprehensive study on the effect of excess vanadium ions on a vanadium-rich ascidian, Ciona intestinalis, using a microarray. RT-PCR and enzyme activity assay were performed from the perspective of redox and accumulation of metal ions in each tissue. Glutathione metabolism-related proteins were significantly up-regulated by V(IV) treatment. Several genes involved in the transport of vanadium and protons, such as Nramp and V-ATPase, were significantly up-regulated by V(IV) treatment. We observed significant up-regulation of glutathione synthesis and degradation pathways in the intestine and branchial sac. In blood cells, expression of Ci-Vanabin4, glutathione reductase activity, glutathione levels, and vanadium concentration increased after V(IV) treatment. V(IV) treatment induced significant changes related to vanadium exclusion, seclusion, and redox pathways in the intestine and branchial sac. It also induced an enhancement of the vanadium reduction and accumulation cascade in blood cells. These differential responses in each tissue in the presence of excess vanadium ions suggest that vanadium accumulation and reduction may have regulatory functions. This is the first report on the gene regulation by the treatment of vanadium-rich ascidians with excess vanadium ions. It provided much information for the mechanism of regulation of gene expression related to vanadium accumulation.     

Type VI collagen deficiency induces osteopenia with distortion of osteoblastic cell morphology

Bone consists of type I collagen as a major protein with minor various matrix proteins. Type VI collagen is one of bone matrix proteins but its function is not known. We therefore examined the effects of type VI collagen deficiency on bone. 3D-μCT analysis revealed that type VI collagen deficiency reduced cancellous bone mass. Cortical bone mass was not affected. Type VI collagen deficiency distorted the shape of osteoblasts both in the cancellous bone and in the cambium layer of periosteal region. Furthermore, type VI collagen deficiency disorganized collagen arrangement. These data indicate that type VI collagen contributes to maintain bone mass.     

Phenotypic characterization of Aspergillus niger and Candida albicans grown under simulated microgravity using a three-dimensional clinostat

The living and working environments of spacecraft become progressively contaminated by a number of microorganisms. A large number of microorganisms, including pathogenic microorganisms, some of which are fungi, have been found in the cabins of space stations. However, it is not known how the characteristics of microorganisms change in the space environment. To predict how a microgravity environment might affect fungi, and thus how their characteristics could change on board spacecraft, strains of the pathogenic fungi Aspergillus niger and Candida albicans were subjected to on-ground tests in a simulated microgravity environment produced by a three-dimensional (3D) clinostat. These fungi were incubated and cultured in a 3D clinostat in a simulated microgravity environment. No positive or negative differences in morphology, asexual reproductive capability, or susceptibility to antifungal agents were observed in cultures grown under simulated microgravity compared to those grown in normal earth gravity (1 G). These results strongly suggest that a microgravity environment, such as that on board spacecraft, allows growth of potentially pathogenic fungi that can contaminate the living environment for astronauts in spacecraft in the same way as they contaminate residential areas on earth. They also suggest that these organisms pose a similar risk of opportunistic infections or allergies in astronauts as they do in people with compromised immunity on the ground and that treatment of fungal infections in space could be the same as on earth.