Microbial subversion of heparan sulfate proteoglycans

The interactions between the host and microbial pathogen largely dictate the onset, progression, and outcome of infectious diseases. Pathogens subvert host components to promote their pathogenesis and, among these, cell surface heparan sulfate proteoglycans are exploited by many pathogens for their initial attachment and subsequent cellular entry. The ability to interact with heparan sulfate proteoglycans is widespread among viruses, bacteria, and parasites. Certain pathogens also use heparan sulfate proteoglycans to evade host defense mechanisms. These findings suggest that heparan sulfate proteoglycans are critical in microbial pathogenesis, and that heparan sulfate proteoglycan-pathogen interactions are potential targets for novel prophylactic and therapeutic approaches.     

The role of caveolae and caveolin 1 in calcium handling in pacing and contraction of mouse intestine

In mouse intestine, caveolae and caveolin‐1 (Cav‐1) are present in smooth muscle (responsible for executing contractions) and in interstitial cells of Cajal (ICC; responsible for pacing contractions). We found that a number of calcium handling/dependent molecules are associated with caveolae, including L‐type Ca²⁺ channels, Na⁺‐Ca²⁺ exchanger type 1 (NCX1), plasma membrane Ca²⁺ pumps and neural nitric oxide synthase (nNOS), and that caveolae are close to the peripheral endo‐sarcoplasmic reticulum (ER‐SR). Also we found that this assemblage may account for recycling of calcium from caveolar domains to SR through L‐type Ca ⁺ channels to sustain pacing and contractions. Here we test this hypothesis further comparing pacing and contractions under various conditions in longitudinal muscle of Cav‐1 knockout mice (lacking caveolae) and in their genetic controls. We used a procedure in which pacing frequencies (indicative of functioning of ICC) and contraction amplitudes (indicative of functioning of smooth muscle) were studied in calcium‐free media with 100 mM ethylene glycol tetra‐acetic acid (EGTA). The absence of caveolae in ICC inhibited the ability of ICC to maintain frequencies of contraction in the calcium‐free medium by reducing recycling of calcium from caveolar plasma membrane to SR when the calcium stores were initially full. This recycling to ICC involved primarily L‐type Ca²⁺ channels; i.e. pacing frequencies were enhanced by opening and inhibited by closing these channels. However, when these stores were depleted by block of the sarco/endoplasmic reticulum Ca²⁺‐ATPase (SERCA) pump or calcium release was activated by carbachol, the absence of Cav‐1 or caveolae had little or no effect. The absence of caveolae had little impact on contraction amplitudes, indicative of recycling of calcium to SR in smooth muscle. However, the absence of caveolae slowed the rate of loss of calcium from SR under some conditions in both ICC and smooth muscle, which may reflect the loss of proximity to store operated Ca channels. We found evidence that these channels were associated with Cav‐1. These changes were all consistent with the hypothesis that a reduction of the extracellular calcium associated with caveolae in ICC of the myenteric plexus, the state of L‐type Ca²⁺ channels or an increase in the distance between caveolae and SR affected calcium handling.     

Pyrogallol inhibits the growth of human pulmonary adenocarcinoma A549 cells by arresting cell cycle and triggering apoptosis

Pyrogallol (PG) is a polyphenol compound and has been known to be an O generator. We evaluated the effects of PG on the growth of human pulmonary A549 cells in relation to the cell cycle and apoptosis. Treatment with 50 or 100 μM PG significantly inhibited the cell growth of A549 for 72 h. DNA flow cytometric analysis indicated that PG slightly induced a G1 phase arrest of the cell cycle at 24 or 48 h, but did not induce the specific cell cycle arrest at 72 h. Intracellular GSH depletion was observed in PG‐treated cells. PG induced apoptosis in A549 cells, as evidenced by sub‐G1 cells, annexin V staining cells, and the loss of mitochondrial membrane potential (Δ Ψ_m). The intracellular ROS (reactive oxygen species) level including O increased in PG‐treated A549 cells at 24 and 48 h, and persisted at 72 h. The changes in GSH as well as ROS levels by PG affected the cell viability in A549 cells. In conclusion, PG inhibited the growth of human pulmonary A549 cells by inducing cell cycle arrest as well as triggering apoptosis. © 2009 Wiley Periodicals, Inc. J Biochem Mol Toxicol 23:36–42, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/jbt.20263     

Diversity of Novel Glutenin Subunits in Bread Wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Glutenin is a major determinant of baking performance and viscoelasticity, which are responsible for high-quality bread with a light porous crumb structure of a well-leavened loaf. We analyzed the diversity of glutenin genes from six wheat cultivars (Korean cvs. Keumgang and Jinpum, Chinese cvs. China-108 and Yeonnon-78, and Japanese cvs. Norin-61 and Kantou-107). Glutenins contain two types of isoforms such as high molecular weight glutenin subunit (HMW-GS) and low molecular weight glutenin subunit (LMW-GS). Glutenin fractions were extracted from wheat endosperm using Osborne solubility method. A total of 217 protein spots were separated on two-dimensional gel electrophoresis with isoelectric focusing (wide range of pH 3–10). The proteins spots were subjected to tryptic digestion and identified by matrix assisted laser desorption/ionization–time of flight mass spectrometry. HMW-GS (43 isoforms) and LMW-GS (seven isoforms) are directly responsible for producing high-quality bread and noodles. Likewise, all the seed storage proteins are digested to provide nutrients for the embryo during seed germination and seedling growth. We identified the diverse glutenin subunits in wheat cultivars and compared the gluten isoforms among different wheat cultivars according to quality. This work gives an insight on the quality improvement in wheat crop.     

Interaction of profilin‐1 and F‐actin via a β‐arrestin‐1/JNK signaling pathway involved in prostaglandin E2‐induced human mesenchymal stem cells migration and proliferation

Although many previous reports have examined the function of prostaglandin E₂ (PGE₂) in the migration and proliferation of various cell types, the role of the actin cytoskeleton in human mesenchymal stem cells (hMSCs) migration and proliferation has not been reported. The present study examined the involvement of profilin‐1 (Pfn‐1) and filamentous‐actin (F‐actin) in PGE₂‐induced hMSC migration and proliferation and its related signal pathways. PGE₂ (10^?6 M) increased both cell migration and proliferation, and also increased E‐type prostaglandin receptor 2 (EP2) mRNA expression, β‐arrestin‐1 phosphorylation, and c‐Jun N‐terminal kinase (JNK) phosphorylation. Small interfering RNA (siRNA)‐mediated knockdown of β‐arrestin‐1 and JNK (‐1, ‐2, ‐3) inhibited PGE₂‐induced growth of hMSCs. PGE₂ also activated Pfn‐1, which was blocked by JNK siRNA, and induced F‐actin level and organization. Downregulation of Pfn‐1 by siRNA decreased the level and organization of F‐actin. In addition, specific siRNA for TRIO and F‐actin‐binding protein (TRIOBP) reduced the PGE₂‐induced increase in hMSC migration and proliferation. Together, these experimental data demonstrate that PGE₂ partially stimulates hMSCs migration and proliferation by interaction of Pfn‐1 and F‐actin via EP2 receptor‐dependent β‐arrestin‐1/JNK signaling pathways. J. Cell. Physiol. 226: 559–571, 2011. © 2010 Wiley‐Liss, Inc.     

Dendritic cell activating factor produced by mouse macrophage hybridoma

A mouse macrophage (M phi) hybridoma which produces a soluble factor responsible for the cooperation between M phi and spleen dendritic cells (DC) was constructed. The antigen-presenting activity and the stimulator cell activity in the allogeneic or syngeneic mixed leukocyte reaction of DC were significantly augmented when DC were incubated with the culture supernatant of the hybridoma treated with various stimulants including latex beads. The monokine present in the culture supernatant of the hybridoma, called dendritic cell-activating factor (DCAF), augmented the production of lymphocyte-activating factor by DC while Ia expression of DCAF-treated DC was not altered. DCAF had no effect on the antigen-presenting activity of peritoneal resident M phi or B cell blasts while the antigen-presenting activity of spleen M phi was enhanced, but the degree of the enhancement was much less than that of spleen DC. DCAF was found to have the following properties: its pI value is between pH 4 and 5; it is stable at pH 2 to 10; and it loses its activity on incubation at 75 C for 30 min. When the culture supernatant of the hybridoma stimulated with latex beads was subjected to gel filtration, the DCAF activity was detected in the 20 Kd to 25 Kd, 30 Kd to 40 Kd, and 50 Kd to 60 Kd molecular weight regions. The 30 Kd to 40 Kd fraction, which is the major peak fraction, was further purified by ion-exchange chromatography followed by gel-filtration chromatography. When each fraction was subjected to SDS-PAGE, a 30 Kd band corresponding to the DCAF activity was observed and DCAF was purified to about 90% purity.     

鳞翅目幼虫分科检索表

昆虫幼期分类的发展是比较晚近的;但不论在理论上或实用上都很重要。国外对於鳞翅目幼虫(通称蠋)的分类进展很快,而在国内还没有引起广泛的注意和研究。过去作者(陆近仁,1943)虽在昆明做过一些工作,但不过是一个起始。我们