Analyses of the general rule on residue pair frequencies in local amino acid sequences of soluble,ordered proteins

The amino acid sequences of soluble, ordered proteins with stable structures have evolved due to biological and physical requirements, thus distinguishing them from random sequences. Previous analyses have focused on extracting the features that frequently appear in protein substructures, such as α‐helix and β‐sheet, but the universal features of protein sequences have not been addressed. To clarify the differences between native protein sequences and random sequences, we analyzed 7368 soluble, ordered protein sequences, by inspecting the observed and expected occurrences of 400 amino acid pairs in local proximity, up to 10 residues along the sequence in comparison with their expected occurrence in random sequence. We found the trend that the hydrophobic residue pairs and the polar residue pairs are significantly decreased, whereas the pairs between a hydrophobic residue and a polar residue are increased. This trend was universally observed regardless of the secondary structure content but was not observed in protein sequences that include intrinsically disordered regions, indicating that it can be a general rule of protein foldability. The possible benefits of this rule are discussed from the viewpoints of protein aggregation and disorder, which are both caused by low‐complexity regions of hydrophobic or polar residues.     

Potential of transfected muscle cells to contribute to DNA vaccine immunogenicity

The mechanism(s) by which DNA vaccines trigger the activation of Ag-specific T cells is incompletely understood. A series of in vivo and in vitro experiments indicates plasmid transfection stimulates muscle cells to up-regulate expression of MHC class I and costimulatory molecules and to produce multiple cytokines and chemokines. Transfected muscle cells gain the ability to directly present Ag to CD8 T cells through an IFN-regulatory factor 3-dependent process. These findings suggest that transfected muscle cells at the site of DNA vaccination may contribute to the magnitude and/or duration of the immune response initiated by professional APCs.     

Distributional change of achromatic epithelial cells of the intestine in the fetuses and young of rats.

The achromatic epithelial cells (AEC), whose cellular materials remain unstained by several stains, e. g., H.E, PAS, Alcian blue, Orange G Anilin blue and Mucicarmin, are detected in the intestinal mucous epithelium of the Iar: Wistar Imamichi rat from the 19th day of gestation to the 21st day after birth. The results of light microscopic and transmission electron microscopic observations suggest that the rats AEC are equivalent to the previously reported vacuolar cells (VC) in cattle and in mice. The present paper describes that rat intestinal AEC appear first in the small intestine, and spread progressively toward the anal direction, while they disappear first in the cecum, and finally disappear at the ileum and the colon 22 days after birth.     

Cytochemical localization of alkaline phosphatase in intestinal metaplasia of the human stomach

Summary Alkaline phosphatase in the brush border of areas of intestinal metaplasia of human stomach was studied cytochemically. All absorptive cells in the upper part of the villi of the duodenum had strong alkaline phosphatase activity but, in areas of intestinal metaplasia, the metaplastic glands consisted of alkaline phosphatase-positive and negative absorptive cells. Alkaline phosphatase activity was found in tall dense microvilli of absorptive cells in areas of intestinal metaplasia and in the duodenum. However, in some areas of metaplastic epithelium, the activity was very weak in some tall dense microvilli of absorptive cells but strong in those of neighbouring absorptive cells. No alkaline phosphatase activity was found in short sparse microvilli of absorptive cells in areas of intestinal metaplasia. The difference in alkaline phosphatase activity in microvilli of different cells in areas of intestinal metaplasia, which is not seen in the duodenum, indicates abnormal morphological and enzymatic differentiation in intestinal metaplasia.     

Purification, cloning, and expression of the prolactin receptor

The rat liver prolactin receptor has been purified to homogeneity, and partial amino acid sequences have been obtained. The structure of the receptor has been deduced from a single complementary DNA clone. The mature protein of 291 amino acids has a relatively long extracellular region, a single transmembrane segment, and a short (57 amino acids) cytoplasmic domain. With the rat cDNA used as a probe, the prolactin receptor in rabbit mammary gland and human hepatoma cells has also been isolated. These tissues contain a second, longer form of the receptor (592 and 598 amino acids, respectively). Both the short and long forms of the prolactin receptor show regions of strong sequence identity with the human and rabbit growth hormone receptors, suggesting that the prolactin and growth hormone receptors originate from a common ancestor.     

Antimitotic quinoid triterpenes from Maytenus chuchuhuasca

Four cytotoxic quinoid triterpenes, tingenone (1), 22 beta-hydroxytingenone (2), pristimerin (3), and celastrol (4), isolated from Maytenus chuchuhuasca, potently inhibit the polymerization of tubulin.     

B cells capturing antigen conjugated with CpG oligodeoxynucleotides induce Th1 cells by elaborating IL-12

APCs initiate T cell-mediated immune responses against foreign Ags. Dendritic cells are professional APCs that play unique roles, including Ag-nonspecific capture, priming of naive T cells, and Th1 induction, whereas B cells generally lack these functions. In this study we uncovered novel aspects of murine B cells as APCs using CpG oligodeoxynucleotides (CpG) conjugated with an Ag. B cells served as efficient APCs independently of surface Igs. This characteristic was underlaid by the CpG-mediated Ag uptake and presentation, which were functional only when CpG were covalently conjugated to Ag. The B cells cultured with CpG-conjugated Ag not only enhanced IFN-gamma formation by Th1 cells, but also induced Th1 differentiation from unprimed T cells. These effects paralleled with the increase in the expression of CD40, CD86, and class II molecules on B cells and the coordinated production of IL-12 by the cells. To our knowledge this is the first report revealing that B cells share with dendritic cells common intrinsic characteristics, such as the Ag-nonspecific capture and presentation, and the induction of Th1 differentiation from unprimed T cells.     

Maternal behavior,milk ejection,and plasma hormones in Hatano high- and low-avoidance rats

Hatano high- and low-avoidance (in a two-way active avoidance task) animals (HAA and LAA, respectively) were successfully selected from a Sprague-Dawley rat population. Pup growth of both strains was dependent on the maternal strain in a cross-fostering study. To determine whether there are strain-specific differences between HAA and LAA in maternal care, both strains of dams were subjected to a test battery as measured by nest building, home cage behavior, pup retrieval, and milk ejection tests. In addition, changes in plasma concentrations of lactotropic and corticotropic hormones such as prolactin, ACTH, and corticosterone were examined during lactation. The test battery indicated that the dams of both strains built good nests and spent an identical amount of time with their offspring. However, LAA dams showed a prolonged latency time for pup retrieval and often left pups outside the nest until the end of the test period. LAA dams also showed a decreased amount of milk ejection, whereas no strain differences were observed in milk ejection after oxytocin treatment. During lactation, a lesser increase in plasma concentrations of prolactin and a greater increase in ACTH were found in LAA dams. There were no differences between the two strains in plasma concentrations of corticosterone. These results clearly demonstrated decreases in maternal behavior and milk ejection in LAA as compared to HAA dams. The present results also suggest that maternal motivation and mechanisms responsible for maternal hormones related to suckling are involved in the degree of pup growth.     

Osmoadaptation-related genes in inner medulla of mouse kidney using microarray

To distinguish biological molecular processes of osmotic stress occurring in inner medulla, we utilized microarrays to monitor expression profiles. RNAs from three segments (cortex, outer medulla, and inner medulla) of mouse kidney were isolated and applied to microarrays. We found 35 genes expressed highly in inner medulla. Next, microarrays for the RNAs from mouse medullary collecting duct cell line (mIMCD) cells and osmotically adapted mIMCD cells (HT cells) were performed (designed as resistant to 1270mOsm/H(2)O). Of 35 genes highly expressed in inner medulla, 6 genes such as; B-cell translocation gene protein (BTG), myc-basic motif homologue, gelsolin, cell surface glycoprotein, laminin beta2, and tubulo-interstitial nephritis antigen, were also expressed highly in HT cells. Using real-time PCR, we confirmed the expression of six genes. Additionally acute osmotic stress induced the BTG. By comparing the inner medulla to a mIMCD3, we identified genes which respond to acute and chronic hyperosmotic stress.