Effects of phosphorylation on the self-assembly of native full-length porcine amelogenin and its regulation of calcium phosphate formation in vitro

The self-assembly of the predominant extracellular enamel matrix protein amelogenin plays an essential role in regulating the growth and organization of enamel mineral during early stages of dental enamel formation. The present study describes the effect of the phosphorylation of a single site on the full-length native porcine amelogenin P173 on self-assembly and on the regulation of spontaneous calcium phosphate formation in vitro. Studies were also conducted using recombinant non-phosphorylated (rP172) porcine amelogenin, along with the most abundant amelogenin cleavage product (P148) and its recombinant form (rP147). Amelogenin self-assembly was assessed using dynamic light scattering (DLS) and transmission electron microscopy (TEM). Using these approaches, we have shown that self-assembly of each amelogenin is very sensitive to pH and appears to be affected by both hydrophilic and hydrophobic interactions. Furthermore, our results suggest that the phosphorylation of the full-length porcine amelogenin P173 has a small but potentially important effect on its higher-order self-assembly into chain-like structures under physiological conditions of pH, temperature, and ionic strength. Although phosphorylation has a subtle effect on the higher-order assembly of full-length amelogenin, native phosphorylated P173 was found to stabilize amorphous calcium phosphate for extended periods of time, in sharp contrast to previous findings using non-phosphorylated rP172. The biological relevance of these findings is discussed.     

Local kallikrein�Ckinin system is involved in podocyte apoptosis under diabetic conditions

The kallikrein-kinin system (KKS) serves as the physiologic counterbalance to the renin-angiotensin system. This study was conducted to examine the changes in the expression of KKS components in podocytes under diabetic conditions and to elucidate the functional role of bradykinin (BK) in diabetes-associated podocyte apoptosis. Thirty-two rats were injected with either diluent (n = 16, C) or with streptozotocin intraperitoneally (n = 16, DM), and 8 rats from each group were treated with BK infusion for 6 weeks. Immortalized mouse podocytes were cultured in media containing 5.6 mmol/l glucose (NG), NG + 10(-7) mol/l AII (AII), or 30 mmol/l glucose (HG) with or without 10(-8) mol/l BK. Urinary albumin excretion was significantly higher in DM rats, and this increase was ameliorated by BK. Not only kininogen, kallikrein, and BK B1- and B2-receptor expression but also BK levels were significantly decreased in DM glomeruli and in cultured podocytes exposed to HG. The changes in the expressions of apoptosis-related molecules and the increase in the number of apoptotic cells in DM glomeruli as well as in HG- and AII-stimulated podocytes were significantly abrogated by BK. The suppressed KSS within podocytes under diabetic condition was associated with podocyte apoptosis, suggesting that BK may be beneficial in preventing podocyte loss in diabetic nephropathy.     

Complete mitochondrial genome sequence of the Korean water deer Hydropotes inermis argyropus (Cervidae, Capreolinae)

The complete mitochondrial genome sequence of Hydropotes inermis argyropus consists of 13 protein-coding, 22 tRNA, and two rRNA genes, and 1 control region (CR). Three overlaps among the 13 protein-coding genes were found: ATP8/ATP6, ND4L/ND4, and ND5/ND6. The CR was located between the tRNA-Pro and tRNA-Phe genes and is 928 bp in length. The typical conserved domains, such as TAS and CSB, were identified in the CR.     

Protective effects of a chalcone derivative against Aβ-induced oxidative stress and neuronal damage

Amyloid Β-peptide (AΒ-peptide)-induced oxidative stress is thought to be a critical component of the pathophysiology of Alzheimer's disease (AD). New chalcone derivatives, the Chana series, were recently synthesized from the retrochalcones of licorice. In this study, we investigated the protective effects of the Chana series against neurodegenerative changes in vitro and in vivo. Among the Chana series, Chana 30 showed the highest free radical scavenging activity (90.7%) in the 1,1-diphenyl-2- picrylhydrazyl assay. Chana 30 also protected against AΒ-induced neural cell injury in vitro. Furthermore, Chana 30 reduced the learning and memory deficits of AΒ(1-42)-peptide injected mice. Taken together, these results suggest that Chana 30 may be a promising candidate as a potent therapeutic agent against neurodegenerative diseases. [BMB reports 2011; 44(11): 730-734].     

Wildlife forensics using mitochondrial DNA sequences: Species identification based on hairs collected in the field and confiscated tanned Felidae leathers

To identify species based on samples without recognizable morphological characteristics, DNA-based approaches are the best option. Here, we describe two cases of the determination of species and geographical origin of wildlife specimens under the regulation of international treaties and domestic laws related to wildlife management in South Korea. First, hairs of suspected wild or reared endangered Asiatic black bears were analyzed using cytochrome oxidase I and the control region. Confiscated Felidae leathers were also investigated using cytochrome b, but they were proven to be fabricated canine leathers. These results were used as scientific evidence for wildlife-related law enforcement. Our results suggest that unrecognizable wildlife specimens can be identified efficiently using DNA sequence-based analysis. Finally, this study shows that conservation genetics research and its applications can be incorporated into wildlife forensic studies.     

Tracing of the Bile-chemotactic migration of juvenile Clonorchis sinensis in rabbits by PET-CT

Background

Adult Clonorchis sinensis live in the bile duct and cause clonorchiasis. It is known that the C. sinensis metacercariae excyst in the duodenum and migrate up to the bile duct through the common bile duct. However, no direct evidence is available on the in vivo migration of newly excysted C. sinensis juveniles (CsNEJs). Advanced imaging technologies now allow the in vivo migration and localization to be visualized. In the present study, we sought to determine how sensitively CsNEJs respond to bile and how fast they migrate to the intrahepatic bile duct using PET-CT.

Methodology/Principal Findings

CsNEJs were radiolabeled with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG). Rabbits with a gallbladder contraction response to cholecystokinin-8 (CCK-8) injection were pre-screened using cholescintigraphy. In these rabbits, gallbladders contracted by 50% in volume at an average of 11.5 min post-injection. The four rabbits examined were kept anesthetized and a catheter inserted into the mid duodenum. Gallbladder contraction was stimulated by injecting CCK-8 (20 ng/kg every minute) over the experiment. Anatomical images were acquired by CT initially and dynamic PET was then carried out for 90 min with a 3-min acquisition per frame. Twelve minutes after CCK-8 injection, about 3,000 ¹⁸F-FDG-labeled CsNEJs were inoculated into the mid duodenum through the catheter. Photon signals were detected in the liver 7–9 min after CsNEJs inoculation, and these then increased in the whole liver with stronger intensity in the central area, presenting that the CsNEJs were arriving at the intrahepatic bile ducts.

Conclusion

In the duodenum, CsNEJs immediately sense bile and migrate quickly with bile-chemotaxis to reach the intrahepatic bile ducts by way of the ampulla of Vater.     

Reference ranges for hemolymph chemistries from Elliptio complanata of North Carolina

Hemolymph chemistries may be useful nonlethal measures of bivalve health. The prognostic value of hemolymph, however, depends on a comparison of chemistry results to reference ranges from healthy individuals. Currently, knowledge of expected hemolymph values in healthy and unhealthy freshwater mussels is extremely limited. The purpose of this study was to develop a set of reference ranges for clinical evaluation of hemolymph from a freshwater mussel species common to southeastern USA. We collected hemolymph from 380 Elliptio complanata from 19 apparently healthy populations from northwest of Raleigh, North Carolina, during May through July 2001. We present reference ranges for hemolymph parameters ammonia, glucose, calcium, magnesium, phosphorus, aspartate aminotransferase (AST), bicarbonate, protein and cell count, and for tissue glycogen. We compare the subpopulations of mussels from regions with an agricultural riparian buffer to those surrounded predominantly by forested lands. We further present correlations noted between hemolymph chemistries and physical or physiologic parameters. The only statistically significant differences between populations contiguous to agricultural and forested lands were in hemolymph calcium and glucose concentrations. Other statistically significant correlations identified were between gravidity and hemolymph protein concentration and tissue glycogen content, as well as between gravidity and parasite burden, and between shell length and hemolymph glucose, AST, calcium and bicarbonate concentrations. The results of this study will aid the interpretation of health measures from populations of E. complanata of similar geographic and seasonal origin.     

SKI306X, an oriental herbal mixture, suppresses gastric leukotriene B4 synthesis without causing mucosal injury and the diclofenac-induced gastric lesions

SKI306X compound is a herbal mixture. This plant was in oriental medicine and was clinically approved for the treatment of osteoarthritis (OA) in Korea. SKI306X was previously found to have anti-inflammatory, analgesic and cartilage protective effects in several experimental models. In this study, SKI306X was investigated for its gastro-sparing effects on the gastric mucosa comparing with those of diclofenac, a conventional NSAID, and celecoxib, a cyclooxygenase-2 (COX-2) specific inhibitor. To investigate acute gastric damaging properties of SKI306X, the stomach of the animals was histologically and immuno-histochemically examined after single or repeated administration, and SKI306X demonstrated excellent gastric tolerability. SKI306X did not cause significant gastric irritation, erosion, or ulceration up to the orally administered dose of 2 g/kg and the intraperitoneal (i.p.) dose of 125 mg/kg. In contrast, diclofenac caused mucosal erosion, ulceration and bleeding at clinically effective doses. To determine the mode of gastro-sparing action, eicosanoid synthesis was examined in gastric mucosa and blood. SKI306X significantly decreased gastric and blood leukotriene B(4) (LTB(4)) production. However, SKI306X showed either no effect or a slight increase in levels of prostaglandin E(2) (PGE(2)). In addition, gastro-protective effects of SKI306X were exhibited by suppressing diclofenac-induced erosion and ulceration of gastric mucosa in a rat model and the possible mechanism of these effects were investigated. These studies demonstrated that SKI306X did not produce any significant damage up to dose of 2 g/kg and was effective in significantly protecting the damage associated to diclofenac-induced gastric ulcerations. SKI306X could spare the gastric mucosa through significantly suppressing gastric leukotriene (LT) synthesis.     

HMGB1 contributes to the development of acute lung injury after hemorrhage

High mobility group box 1 (HMGB1) is a novel late mediator of inflammatory responses that contributes to endotoxin-induced acute lung injury and sepsis-associated lethality. Although acute lung injury is a frequent complication of severe blood loss, the contribution of HMGB1 to organ system dysfunction in this setting has not been investigated. In this study, HMGB1 was detected in pulmonary endothelial cells and macrophages under baseline conditions. After hemorrhage, in addition to positively staining endothelial cells and macrophages, neutrophils expressing HMGB1 were present in the lungs. HMGB1 expression in the lung was found to be increased within 4 h of hemorrhage and then remained elevated for more than 72 h after blood loss. Neutrophils appeared to contribute to the increase in posthemorrhage pulmonary HMGB1 expression since no change in lung HMGB1 levels was found after hemorrhage in mice made neutropenic with cyclophosphamide. Plasma concentrations of HMGB1 also increased after hemorrhage. Blockade of HMGB1 by administration of anti-HMGB1 antibodies prevented hemorrhage-induced increases in nuclear translocation of NF-kappa B in the lungs and pulmonary levels of proinflammatory cytokines, including keratinocyte-derived chemokine, IL-6, and IL-1 beta. Similarly, both the accumulation of neutrophils in the lung as well as enhanced lung permeability were reduced when anti-HMGB1 antibodies were injected after hemorrhage. These results demonstrate that hemorrhage results in increased HMGB1 expression in the lungs, primarily through neutrophil sources, and that HMGB1 participates in hemorrhage-induced acute lung injury.     

Vaccine-induced tumor-specific immunity despite severe B-cell depletion in mantle cell lymphoma

The role of B cells in T-cell priming is unclear, and the effects of B-cell depletion on immune responses to cancer vaccines are unknown. Although results from some mouse models suggest that B cells may inhibit induction of T cell-dependent immunity by competing with antigen-presenting cells for antigens, skewing T helper response toward a T helper 2 profile and/or inducing T-cell tolerance, results from others suggest that B cells are necessary for priming as well as generation of T-cell memory. We assessed immune responses to a well-characterized idiotype vaccine in individuals with severe B-cell depletion but normal T cells after CD20-specific antibody-based chemotherapy of mantle cell lymphoma in first remission. Humoral antigen- and tumor-specific responses were detectable but delayed, and they correlated with peripheral blood B-cell recovery. In contrast, vigorous CD4(+) and CD8(+) antitumor type I T-cell cytokine responses were induced in most individuals in the absence of circulating B cells. Analysis of relapsing tumors showed no mutations or change in expression of target antigen to explain escape from therapy. These results show that severe B-cell depletion does not impair T-cell priming in humans. Based on these results, it is justifiable to administer vaccines in the setting of B-cell depletion; however, vaccine boosts after B-cell recovery may be necessary for optimal humoral responses.