New clade of silicified bolidophytes that belong to Triparma (Bolidophyceae,Stramenopiles)

The small phytoplankton genus Triparma belongs to the class Bolidophyceae and contains two distinct forms: silicified species and naked flagellated species (formerly Bolidomonas). Recent studies showed that four silicified species/strains (Triparma laevis f. inornata, T. laevis f. longispina, T. strigata, and T. aff. verrucosa) belong to a single clade that is paraphyletic, because it also contains an unclassified flagellated strain, and is sister to a flagellated species, T. eleuthera. In this study, we isolated and characterized two new strains of silicified species to test the phylogenetic unity of silicified bolidophytes. The isolates were identified as T. retinervis strains because they possessed fine areolation on the cell wall. 18S rDNA and rbcL phylogenetic analyses demonstrated that T. retinervis formed a new silicified clade that is sister to the flagellated species T. pacifica. This reveals that there are at least two distinct clades including both silicified and flagellated Triparma species.     

Expression of cell adhesion molecule,Gicerin/CD146 during the formation of heart and in the cardiac hypertrophy

Molecular and Cellular Biochemistry - Gicerin/CD146 is a cell adhesion molecule which belongs to the immunoglobulin (Ig) superfamily. We have reported the existence of gicerin/CD146 in the nervous...     

D1- and D2-like receptors differentially mediate the effects of dopaminergic transmission on cost–benefit evaluation and motivation in monkeys

It has been widely accepted that dopamine (DA) plays a major role in motivation, yet the specific contribution of DA signaling at D₁-like receptor (D₁R) and D₂-like receptor (D₂R) to cost–benefit trade-off remains unclear. Here, by combining pharmacological manipulation of DA receptors (DARs) and positron emission tomography (PET) imaging, we assessed the relationship between the degree of D₁R/D₂R blockade and changes in benefit- and cost-based motivation for goal-directed behavior of macaque monkeys. We found that the degree of blockade of either D₁R or D₂R was associated with a reduction of the positive impact of reward amount and increasing delay discounting. Workload discounting was selectively increased by D₂R antagonism. In addition, blocking both D₁R and D₂R had a synergistic effect on delay discounting but an antagonist effect on workload discounting. These results provide fundamental insight into the distinct mechanisms of DA action in the regulation of the benefit- and cost-based motivation, which have important implications for motivational alterations in both neurological and psychiatric disorders.

Using quantitatively controlled pharmacological manipulations, this study teases apart the role of D1- and D2-like dopamine receptors in motivation and goal-directed behavior in monkeys, revealing complementary roles of two dopamine receptor subtypes in the computation of the cost/benefit trade-off to guide action.     

srGAP1 regulates lamellipodial dynamics and cell migratory behavior by modulating Rac1 activity

The distinct levels of Rac activity differentially regulate the pattern of intrinsic cell migration. However, it remains unknown how Rac activity is modulated and how the level of Rac activity controls cell migratory behavior. Here we show that Slit-Robo GAP 1 (srGAP1) is a modulator of Rac activity in locomotive cells. srGAP1 possesses a GAP activity specific to Rac1 and is recruited to lamellipodia in a Rac1-dependent manner. srGAP1 limits Rac1 activity and allows concomitant activation of Rac1 and RhoA, which are mutually inhibitory. When both GTPases are activated, the protrusive structures caused by Rac1-dependent actin reorganization are spatially restricted and periodically destabilized, causing ruffling by RhoA-induced actomyosin contractility. Depletion of srGAP1 overactivates Rac1 and inactivates RhoA, resulting in continuous spatiotemporal spreading of lamellipodia and a modal shift of intrinsic cell motility from random to directionally persistent. Thus srGAP1 is a key determinant of lamellipodial dynamics and cell migratory behavior.     

Targeting Superoxide Dismutase to Renal Proximal Tubule Cells Attenuates Vancomycin-induced Nephrotoxicity in Rats

Vancomycin hydrochloride (VCM), a glycopeptide antibiotic, has a broad spectrum against methicillin-resistant Staphylococcus aureus (MRSA). As it is known to induce renal dysfunction, the dose and the duration of its administration are limited. Moreover, the mechanism of VCM-induced renal dysfunction remains to be unclear. To evaluate the involvement of free radical on VCM-induced renal dysfunction, we carried out analysis with a hexamethylenediamine-conjugated superoxide dismutase (AH-SOD) which rapidly accumulates in renal proximal tubule cells and inhibits oxidative injury of the kidney. Male Wistar rats (weighing 200-210 g) were intraperitonealy administered with 200 mg/kg of VCM twice a day for 7 days. AH-SOD 5 mg/kg/day was subcutaneously injected 5 min before every VCM injection. VCM induced renal injury dose-dependently. Biochemical analyses revealed that plasma levels of blood urea nitrogen and creatinine significantly increased in the VCM-treated group by an AH-SOD-inhibitable mechanism. VCM simultaneously elicited an increase of 8-OHdG levels and chemiluminescence intensity of free radical generation in the kidney. Histological examination revealed that VCM also elicited a marked destruction of glomeruli and necrosis of proximal tubules. AH-SOD inhibited these phenomena in the kidney. These results suggested that oxidative stress might underlie the pathogenesis of VCM-induced nephrotoxicity and targeting SOD and/or related antioxidants to renal proximal tubules might permit the administration of higher doses of VCM sufficient for eradication of MRSA without causing renal injury.     

Fluorescent-Based Methods for Gene Knockdown and Functional Cardiac Imaging in Zebrafish

A notable advantage of zebrafish as a model organism is the ease of gene knockdown using morpholino antisense oligonucleotide (MO). However, zebrafish morphants injected with MO for a target protein often show heterogeneous phenotypes, despite controlling the injection volume of the MO solution in all embryos. We developed a method for estimating the quantity of MO injected into each living morphant, based on the co-injection of a control MO labeled with the fluorophore lissamine. By applying this method for knockdown of cardiac troponin T (tnnt2a) in zebrafish, we could efficiently select the partial tnnt2a-depleted zebrafish with a decreased heart rate and impairment of cardiac contraction. To investigate cardiac impairment of the tnnt2a morphant, we performed fluorescent cardiac imaging using Bodipy-ceramide. Cardiac image analysis showed moderate reduction of tnnt2a impaired diastolic distensibility and decreased contraction and relaxation velocities. To the best of our knowledge, this is the first report to analyze the role of tnnt2a in cardiac function in tnnt2a-depleted living animals. Our combinatorial approach can be applied for analyzing the molecular function of any protein associated with human cardiac diseases.     

Studies on Griseolic Acid Derivatives X. Synthesis and Phosphodiesterase Inhibitory Activity of 2-Substituted Derivatives of Griseolic Acid

Abstract

Griseolic acid derivatives which were modified at the 2-and/or 6-positions were first synthesized from griseolic acid by a ring opening—reclosure reaction of the adenine ring. Among these derivatives, the 2-amino-6-deamino-6-hydroxyl (guanine) derivative showed 3.3 and 45 times stronger inhibitory activity against cAMP and cGMP PDE, respectively, than those of griseolic acid. Structure-activity relationships among these derivatives are also discussed.     

Naemacyclus culmigenus,a newly reported potential pathogen to Miscanthus sinensis,new to Japan

Since the summer of 2010, a discomycete with erumpent apothecia associated with a leaf blight of Miscanthus leaves, were often collected. The morphological characteristics of the fungus suggested it was a member of the Helotiales rather than the Rhytismatales and this was supported by a phylogenetic analysis. Based on a morphological comparison with the type specimen of Naemacyclus culmigenus, currently known from Poaceae (Andropogon and Panicum), it was identified as N. culmigenus, new to Japan. The molecular phylogenetic analysis showed that the generic delimitation of Naemacyclus and related species requires clarification, as does their higher classification within the Leotiomycetes.     

Molecular Markers for Granulovacuolar Degeneration Are Present in Rimmed Vacuoles

Background

Rimmed vacuoles (RVs) are round-oval cytoplasmic inclusions, detected in muscle cells of patients with myopathies, such as inclusion body myositis (IBM) and distal myopathy with RVs (DMRV). Granulovacuolar degeneration (GVD) bodies are spherical vacuoles containing argentophilic and hematoxyphilic granules, and are one of the pathological hallmarks commonly found in hippocampal pyramidal neurons of patients with aging-related neurodegenerative diseases, such as Alzheimer''s disease and Parkinson''s disease. These diseases are common in the elderly and share some pathological features. Therefore, we hypothesized that mechanisms of vacuolar formation in RVs and GVD bodies are common despite their role in two differing pathologies. We explored the components of RVs by immunohistochemistry, using antibodies for GVD markers.

Methods

Subjects included one AD case, eight cases of sporadic IBM, and three cases of DMRV. We compared immunoreactivity and staining patterns for GVD markers. These markers included: (1) tau-modifying proteins (caspase 3, cyclin-dependent kinase 5 [CDK5], casein kinase 1δ [CK1δ], and c-jun N-terminal kinase [JNK]), (2) lipid raft-associated materials (annexin 2, leucine-rich repeat kinase 2 [LRRK2], and flotillin-1), and (3) other markers (charged multi-vesicular body protein 2B [CHMP2B] and phosphorylated transactive response DNA binding protein-43 [pTDP43]) in both GVD bodies and RVs. Furthermore, we performed double staining of each GVD marker with pTDP43 to verify the co-localization.

Results

GVD markers, including lipid raft-associated proteins and tau kinases, were detected in RVs. CHMP2B, pTDP43, caspase 3, LRRK2, annexin 2 and flotillin-1 were detected on the rim and were diffusely distributed in the cytoplasm of RV-positive fibers. CDK5, CK1δ and JNK were detected only on the rim. In double staining experiments, all GVD markers colocalized with pTDP43 in RVs.

Conclusions

These results suggest that RVs of muscle cells and GVD bodies of neurons share a number of molecules, such as raft-related proteins and tau-modifying proteins.