Molecular phylogeny of Pneumocystis based on 5.8S rRNA gene and the internal transcribed spacers of rRNA gene sequences

To clarify the phylogenetic relationships and species status of Pneumocystis, the 5.8S rRNA gene and the internal transcribed spacers (ITS, 1 and 2) of Pneumocystis rRNA derived from rat, gerbil and human were amplified, cloned and sequenced. The genetic distance matrix of six Pneumocystis species compared with other fungi like Taphrina and Saccharomyces indicated that the Pneumocystis genus contained multiple species including Pneumocystis from gerbil. The phylogenetic tree also showed that Pneumocystis from human and monkey formed one group and four rodent Pneumocystis formed another group. Among the four members, Pneumocystis wakefieldiae was most closely related to Pneumocystis murina and Pneumocystis carinii, and was least related to gerbil Pneumocystis.     

Effects of static magnetic fields on the physical and chemical properties of cell culture medium RPM1 1640

RPMI 1640 culture medium was chosen to simulate body fluids, and after exposure to 0.085 approximately 0.092 T static magnetic fields (SMF), surface tension, pH, dissolved oxygen, and UV-visible spectrum were measured. Compared with the control group in the normal geomagnetic field, the pH value increased about 0.14 units, dissolved oxygen increased about 14%, and the UV-visible spectra were different in peak intensity but without a shift in the peak. Surface tension showed no significant difference in the two groups. This data suggests that SMF can change some of the physical and chemical properties of RPM1 1640 solution, and may contribute to understanding biological effects of SMF.     

Oxytocin is expressed by both intrinsic sensory and secretomotor neurons in the enteric nervous system of guinea pig

Single- and double-immunostaining techniques were used systematically to study the distribution pattern and neurochemical density of oxytocin-immunoreactive (-ir) neurons in the digestive tract of the guinea pig. Oxytocin immunoreactivity was distributed widely in the guinea pig gastrointestinal tract; 3%, 13%, 17%, 15%, and 10% of ganglion neurons were immunoreactive for oxytocin in the myenteric plexuses of the gastric corpus, jejunum, ileum, proximal colon, and distal colon, respectively, and 36%, 40%, 52%, and 56% of ganglion neurons were immunoreactive for oxytocin in the submucosal plexuses of the jejunum, ileum, proximal colon, and distal colon, respectively. In the myenteric plexus, oxytocin was expressed exclusively in the intrinsic enteric afferent neurons, as identified by calbindin 28 K. In the submucosal plexuses, oxytocin was expressed in non-cholinergic secretomotor neurons, as identified by vasoactive intestinal polypeptide. Oxytocin-ir nerve fibers in the inner circular muscle layer possibly arose from the myenteric oxytocin-ir neurons, and oxytocin-ir nerve fibers in the mucosa possibly arose from both the myenteric and submucosal oxytocin-ir neurons. Thus, oxytocin in the digestive tract might be involved in gastrointestinal tract motility mainly via the regulation of the inner circular muscle and the balance of the absorption and secretion of water and electrolytes.     

Metabolome profiling reveals metabolic cooperation between Bacillus megaterium and Ketogulonicigenium vulgare during induced swarm motility

The metabolic cooperation in the ecosystem of Bacillus megaterium and Ketogulonicigenium vulgare was investigated by cultivating them spatially on a soft agar plate. We found that B. megaterium swarmed in a direction along the trace of K. vulgare on the agar plate. Metabolomics based on gas chromatography coupled with time-of-flight mass spectrometry (GC-TOF-MS) was employed to analyze the interaction mechanism between the two microorganisms. We found that the microorganisms interact by exchanging a number of metabolites. Both intracellular metabolism and cell-cell communication via metabolic cooperation were essential in determining the population dynamics of the ecosystem. The contents of amino acids and other nutritional compounds in K. vulgare were rather low in comparison to those in B. megaterium, but the levels of these compounds in the medium surrounding K. vulgare were fairly high, even higher than in fresh medium. Erythrose, erythritol, guanine, and inositol accumulated around B. megaterium were consumed by K. vulgare upon its migration. The oxidization products of K. vulgare, including 2-keto-gulonic acids (2KGA), were sharply increased. Upon coculturing of B. megaterium and K. vulgare, 2,6-dipicolinic acid (the biomarker of sporulation of B. megaterium), was remarkably increased compared with those in the monocultures. Therefore, the interactions between B. megaterium and K. vulgare were a synergistic combination of mutualism and antagonism. This paper is the first to systematically identify a symbiotic interaction mechanism via metabolites in the ecosystem established by two isolated colonies of B. megaterium and K. vulgare.     

AIDA Selectively Mediates Downregulation of Fat Synthesis Enzymes by ERAD to Retard Intestinal Fat Absorption and Prevent Obesity

1. Download high-res image (216KB)
2. Download full-size image

     

Iron metabolism in diabetes-induced Alzheimer’s disease: a focus on insulin resistance in the brain

Alzheimer’s disease (AD) is characterized by an excessive accumulation of toxic amyloid beta (Aβ) plaques and memory dysfunction. The onset of AD is influenced by age, genetic background, and impaired glucose metabolism in the brain. Several studies have demonstrated that diabetes involving insulin resistance and glucose tolerance could lead to AD, ultimately resulting in cognitive dysfunction. Even though the relationship between diabetes and AD was indicated by significant evidences, the critical mechanisms and metabolic alterations in diabetes induced AD are not clear until now. Recently, iron metabolism has been shown to play multiple roles in the central nervous system (CNS). Iron deficiency and overload are associated with neurodegenerative diseases. Iron binds to Aβ and subsequently regulates Aβ toxicity in the CNS. In addition, previous studies have shown that iron is involved in the aggravation of insulin resistance. Considering these effects of iron metabolism in CNS, we expect that iron metabolism may play crucial roles in diabetic AD brain. Thus, we review the recent evidence regarding the relationship between diabetes-induced AD and iron metabolism.     

Short-term in vitro culture of purity and highly functional rat bone marrow-derived mast cells

Mast cells (MCs) are responsible for the innate immune response. Rat MCs are more suitable than mouse MCs as models of specific parasite infection processes and ovalbumin-induced asthma. Rat peritoneum-derived MCs and RBL-2H3 cells (an MC cell line) are widely used in disease studies. However, the application of rat bone marrow-derived MCs (BMMCs) are poorly documented in terms of the methodology of rat BMMC isolation. Here, we describe a relatively rapid, efficient, and simple method for the cultivation of rat BMMCs. As compared to previous protocols, rat BMMCs produced with the proposed protocol exhibited advantages in differentiation, proliferation, lifespan, and functionality, which should prove useful for studies of mucosal MC diseases in specific rat models.     

纤维素衍生物在固定酶和药物中的应用

本文综述了纤维素衍生物在固定酶和药物中的应用。     

Characterization of a novel nm23 gene and its potential roles in gametogenesis in the prawn Macrobrachium rosenbergii (de Man, 1879) (Crustacea: Decapoda)

Nm23 is a family of genes encoding the nucleoside diphosphate (NDP) kinase, which functions in a wide variety of biological processes, including growth, development, differentiation and tumor metastasis. In this study, a novel nm23 gene, designated as Mrnm23, was identified from the freshwater giant prawn Macrobrachium rosenbergii. The full-length cDNA was 776 bp in length, encoding for a protein of 176 amino acids with one typical NDP kinase domain that harbored all the crucial residues for nucleotide binding and enzymatic activity. Like human novel nm23-H1B, the putative protein contained a unique 21-amino-acid NH₂-terminal extension as compared to human nm23 (nm23-H1) homologs. Further, 3 extra amino acid residues prolonged the COOH-terminus. The Mrnm23 was ubiquitously expressed in all tissues examined, including androgenic gland, gill, heart, liver, muscle, ovary, and testis. In situ hybridization to gonad sections indicated that the Mrnm23 mRNA was localized in the cytoplasm of cup-base of differentiating spermatids, in the spike of the umbrella-shaped spermatozoa and in the cytoplasm of the early previtellogenic oocytes, suggesting that the Mrnm23 has potential roles in spermiogenesis and early differentiation of oocyte.