Th2 polarization enhanced by oral administration of higher doses of antigen

Although oral administration of a soluble proteinantigen can induce various immune responses, theeffect of the dosage of oral antigen on thepredominance of Th2-type cytokine and antibodyresponses has not been well clarified yet. In thepresent study, we fed T cell receptor (TCR) transgenic(tg) mice various amounts of chicken ovalbumin (0.1,5, and 250 mg) and examined the resulting immuneresponses to this antigen. In these TCR tg mice, theresponses of antigen-specific T cells were greatlyamplified concomitantly with significantantigen-specific cytokine secretion. We found that ahigh dose (250 mg) of antigen significantlyupregulated the serum antigen-specific IgG1 and IgAantibody responses in mice later intraperitoneallyinjected with antigen plus adjuvant. The miceadministered the same oral dose but not immunizedshowed upregulation of Th2-type IL-4 and IL-5secretion and downregulation of Th1-type IL-2 andIFN-. This enhancement of Th2-type cytokineand antibody responses was more marked when largerdoses of antigen orally administered. These resultsdemonstrated that antigen feeding induces thedevelopment of T cells secreting Th2-type cytokines ina dose-dependent manner and that these T cells have ahelper function for the production of antibodies ofthe Th2-type isotypes. This experimental system shouldbe useful to screen foods and other substances thatcan modulate Th2-type responses relating to allergy.     

An antibiotic from Penicillium sp. covering the cocoon of the leaf-rolling moth, Dactylioglypha tonica

An antibiotic-producing Penicillium sp. strain was isolated from cocoons of the leaf-rolling moth, Dactylioglypha tonica. An antibacterial compound was isolated from the cultured broth, and the chemical structure of the principle was determined by spectroscopic data to be a derivative of isocoumarincarboxylate.     

Laryngeal endocrine cells: topographic distribution and adaptation to chronic hypercapnic hypoxia

The morphology, topographic distribution, effects of denervation, and exposure to hypercapnic hypoxia of endocrine cells were examined in rat larynx. The endocrine cells, which were immunoreactive for protein gene product 9.5 (PGP 9.5) and calcitonin gene-related peptide (CGRP), were observed within the epithelial layer of the laryngeal cavity and in the laryngeal gland, while solitary endocrine cells with apical and/or basal cytoplasmic processes appeared near the glottis. After denervation of the left cervical vagosympathetic trunk and the superior laryngeal nerve, the number of mucosal endocrine cells in the denervated side was not significantly different from that in the intact side. After exposure to hypercapnic hypoxia for 3 months, the number of endocrine cells with PGP 9.5 and CGRP was markedly increased. In conclusion, the secretion of laryngeal endocrine cells may be stimulated by CO2 rather than O2. Furthermore, the endocrine cells and the sensory and autonomic nervous system may regulate each other by an axon reflex mechanism. Endocrine cells appear to play a very important role in the local regulation of the laryngeal mucosa.     

Bioactive peptides derived from food proteins preventing lifestyle-related diseases

Many kinds of bioactive peptides which might prevent lifestyle-related diseases are released from food proteins after enzymatic digestion. Inhibitory peptides for angiotensin I-converting enzyme (ACE) having anti-hypertensive effect have been isolated from enzymatic digests of various food proteins. LKPNM, which was isolated from the thermolysin digest of dried bonito was activated 8-fold by ACE itself and showed a prolonged effect after oral administration. Two vasorelaxing peptides, ovokinin and ovokinin(2-7), showing antihypertensive effect after oral administration were obtained from ovalbumin digests. We found that low molecular weight peptides derived from food proteins lowered serum cholesterol without increasing excretion of cholesterol and bile acids. An immunostimulating peptide isolated from an enzymatic digest of soybean protein prevented alopecia induced by cancer chemotherapy.     

A Robertsonian translocation, rob(2;28), found in Vietnamese cattle

A new Robertsonian translocation, rob(2;28), was discovered in a local population of the Vietnamese Cattle. The animal (2n = 59, XY) was found by Q- and R-banding to be a heterozygous carrier of a centric fusion translocation involving chromosomes 2 and 28. FISH analysis using a bovine satellite I DNA probe demonstrated that the centromeric heterochromatin block of the rob(2;28) chromosome become much smaller than its ancestors suggesting a monocentric nature of this centric fusion. This is the first report identifying a Robertsonian translocation in Southeast Asian cattle by karyotyping of banded chromosomes.     

Identification of heading date quantitative trait locus Hd6 and characterization of its epistatic interactions with Hd2 in rice using advanced backcross progeny

A backcrossed population (BC(4)F(2)) derived from a cross between a japonica rice variety, Nipponbare, as the recurrent parent and an indica rice variety, Kasalath, as the donor parent showed a long-range variation in days to heading. Quantitative trait loci (QTL) analysis revealed that two QTL, one on chromosome 3, designated Hd6, and another on chromosome 2, designated Hd7, were involved in this variation; and Hd6 was precisely mapped as a single Mendelian factor by using progeny testing (BC(4)F(3)). The nearly isogenic line with QTL (QTL-NIL) that carries the chromosomal segment from Kasalath for the Hd6 region in Nipponbare's genetic background was developed by marker-assisted selection. In a day-length treatment test, the QTL-NIL for Hd6 prominently increased days to heading under a 13.5-hr day length compared with the recurrent parent, Nipponbare, suggesting that Hd6 controls photoperiod sensitivity. QTL analysis of the F(2) population derived from a cross between the QTL-NILs revealed existence of an epistatic interaction between Hd2, which is one of the photoperiod sensitivity genes detected in a previous analysis, and Hd6. The day-length treatment tests of these QTL-NILs, including the line introgressing both Hd2 and Hd6, also indicated an epistatic interaction for photoperiod sensitivity between them.     

Cloning of a rat glia maturation factor-gamma (rGMFG) cDNA and expression of its mRNA and protein in rat organs

We isolated a rat glia maturation factor-gamma(rGMFG) cDNA and examined the tissue distribution of GMFG in rat by Northern and Western blot analyses. Sequence analysis of the entire cDNA revealed an open reading frame of 426 nucleotides with a deduced protein of 142 amino acid residues. The deduced amino acid sequence of the putative product is highly homologous (78.9%) to rat glia maturation factor-beta (rGMFB). Northern blot analysis indicated that a 0.9-kb mRNA is predominantly expressed in rat thymus, testis, and spleen. GMFG showed a different tissue distribution from GMFB, being present predominantly in proliferative and differentiative organs.     

Substrate specificity of bovine cathepsin B and its inhibition by CA074, based on crystal structure refinement of the complex

The crystal structure of the bovine spleen cathepsin B (BSCB)-CA074 complex was refined to R = 0.152 using X-ray diffraction data up to 2.18 A resolution. BSCB is characterized by an extra Cys148-Cys252 disulfide bridge, as compared with rat and human CBs. Although the crystal structures of these enzymes showed similar overall folding, a difference was observed in the occluding loop, a structural element specific only to CB. Comparison of the torsion angles indicated the different flexibilities of their loop structures. The oxirane C6 atom of CA074 was covalently bonded to the Cys29 S(gamma) atom (C3-S(gamma)=1.81 A), where the S-configuration was transformed to the R-form. Concerning the oxirane carbon atom that participates in the covalent bonding with the Cys residue, an acceptable rule has been proposed. The substrate specificities at the Sn (n = 1-3) and Sn' (n=1 and 2) subsites of CB, together with the interaction features as to CA074, have been discussed in comparison with the crystal structure of the papain-CA028 (a CA074-related inhibitor) complex.