Swimming behavior of Chinese sturgeon in natural habitat as compared to that in a deep reservoir: preliminary evidence for anthropogenic impacts

Unusually deep water due to dam construction has the potential to negatively effect endangered sturgeons, which lack a physiological mechanism to inflate their swimbladder and may be unable to remain buoyant under high pressure at depth. In a previous study, some juvenile sturgeons released in a deep (>100?m) reservoir lost buoyancy and stayed nearly motionless on the bottom. However, it is not clear whether this behavior represents a negative effect of the dam, because natural sturgeon swimming behavior is unknown. In this study, we attached multi-sensor data loggers to nine wild adult Chinese sturgeons Acipenser sinensis in an unimpounded reach of the Yangtze River, China. The depth utilization, tail beating activity, swim speed, and body inclination of these fish were monitored for 1?C3?days. Fish swam up and down successively in the water column (mean depth, 9.9?m) with a cycle of 100?C1,000?s during 64?% of the time on average, and stayed at depth, presumably on the riverbed, during rest periods. Tail beats were continuous (mean frequency, 0.77?Hz) throughout the records, indicating that their buoyancy was maintained. These results contrast with the previous study, suggesting that the behavior observed in the reservoir is unusual and that deep water poses a risk of losing buoyancy for sturgeons. Furthermore, all fish intensively swam (maximum speed, 3.0?m?s^?1) to the river surface at a mean frequency of 0.35 times per hour??a behavior that could explain why ship strikes are a serious cause of mortality in sturgeons.     

Localization of attachment area of the symbiotic Chlorella variabilis of the ciliate Paramecium bursaria during the algal removal and reinfection

Chlorella spp. and ciliate Paramecium bursaria share a mutual symbiosis. However, both alga-removed P. bursaria and isolated symbiotic algae can grow independently. Additionally, mixing them experimentally can cause algal reinfection through host phagocytosis. Although the symbiotic algal localization beneath the host cell cortex is a prerequisite phenomenon for maintenance of the relationship of their endosymbiosis, how and where the algae locate beneath the host cell cortex remains unknown. To elucidate this phenomenon, algal distribution patterns during algal removal and reinfection were observed. During algal removal, algae at the host anterior cortex were easier to remove than at the posterior and ventral or dorsal cortex areas. During algal reinfection, the algae after separation from the host digestive vacuoles tended to localize beneath the host ventral or dorsal cortex more readily than that at other cortices. Algae that reinfected trichocyst-removed paramecia didn’t show this localization. Trichocyst-discharge experiments clarified that trichocysts of the anterior cortex are difficult to remove. In 14 strains of P. bursaria, some of the paramecia lacked their symbiotic algae at the anterior cortex. These observations demonstrate that symbiotic algae of P. bursaria are difficult to localize at the anterior cortex and that they are easy to remove from the area.     

Adventitial Vasa Vasorum Arteriosclerosis in Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a common disease among elderly individuals. However, the precise pathophysiology of AAA remains unknown. In AAA, an intraluminal thrombus prevents luminal perfusion of oxygen, allowing only the adventitial vaso vasorum (VV) to deliver oxygen and nutrients to the aortic wall. In this study, we examined changes in the adventitial VV wall in AAA to clarify the histopathological mechanisms underlying AAA. We found marked intimal hyperplasia of the adventitial VV in the AAA sac; further, immunohistological studies revealed proliferation of smooth muscle cells, which caused luminal stenosis of the VV. We also found decreased HemeB signals in the aortic wall of the sac as compared with those in the aortic wall of the neck region in AAA. The stenosis of adventitial VV in the AAA sac and the malperfusion of the aortic wall observed in the present study are new aspects of AAA pathology that are expected to enhance our understanding of this disease.     

Robust and Highly-Efficient Differentiation of Functional Monocytic Cells from Human Pluripotent Stem Cells under Serum- and Feeder Cell-Free Conditions

Monocytic lineage cells (monocytes, macrophages and dendritic cells) play important roles in immune responses and are involved in various pathological conditions. The development of monocytic cells from human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) is of particular interest because it provides an unlimited cell source for clinical application and basic research on disease pathology. Although the methods for monocytic cell differentiation from ESCs/iPSCs using embryonic body or feeder co-culture systems have already been established, these methods depend on the use of xenogeneic materials and, therefore, have a relatively poor-reproducibility. Here, we established a robust and highly-efficient method to differentiate functional monocytic cells from ESCs/iPSCs under serum- and feeder cell-free conditions. This method produced 1.3×10⁶±0.3×10⁶ floating monocytes from approximately 30 clusters of ESCs/iPSCs 5–6 times per course of differentiation. Such monocytes could be differentiated into functional macrophages and dendritic cells. This method should be useful for regenerative medicine, disease-specific iPSC studies and drug discovery.     

Carbon‐11 radiolabeling of an oligopeptide containing tryptophan hydrochloride via a Pictet‐Spengler reaction using carbon‐11 formaldehyde

A procedure for the synthesis of a¹¹C‐labeled oligopeptide containing [1‐¹¹C]1,2,3,4‐tetrahydro‐β‐carboline‐3‐carboxylic acid ([1‐¹¹C]Tpi) from the corresponding Trp?HCl‐containing peptides has been developed involving a Pictet‐Spengler reaction with [¹¹C]formaldehyde. The synthesis of [1‐¹¹C]Tpi from Trp and [¹¹C]formaldehyde was examined as a model reaction with the aim of developing a facile and effective method for the labeling of peptides with carbon‐11. The Pictet‐Spengler reaction of Trp and [¹¹C]formaldehyde in acidic media (TsOH or HCl) afforded the desired [1‐¹¹C]Tpi in a moderate radiochemical yield. Herein, the application of a Pictet‐Spengler reaction to an aqueous solution of Trp?HCl gave the desired product with a radiochemical yield of 45.2%. The RGD peptide cyclo[Arg‐Gly‐Asp‐D‐Tyr‐Lys] was then selected as a substrate for the labeling reaction with [¹¹C]formaldehyde. The radiolabeling of a Trp?HCl‐containing RGD peptide using the Pictet‐Spengler reaction was successful. Furthermore, the remote‐controlled synthesis of a [1‐¹¹C]Tpi‐containing RGD peptide was attempted by using an automatic production system to generate [¹¹C]CH₃I. The radiochemical yield of the [1‐¹¹C]Tpi‐containing RGD at the end of synthesis (EOS) was 5.9 ± 1.9% (n = 4), for a total synthesis time of about 35 min. The specific activity was 85.7 ± 9.4 GBq/µmol at the EOS. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.     

Discovery of a novel type of autophagy targeting RNA

Regulated degradation of cellular components by lysosomes is essential to maintain biological homeostasis. In mammals, three forms of autophagy, macroautophagy, microautophagy and chaperone-mediated autophagy (CMA), have been identified. Here, we showed a novel type of autophagy, in which RNA is taken up directly into lysosomes for degradation. This pathway, which we term “RNautophagy,” is ATP-dependent, and unlike CMA, is independent of HSPA8/Hsc70. LAMP2C, a lysosomal membrane protein, serves as a receptor for this pathway. The cytosolic tail of LAMP2C specifically binds to almost all total RNA derived from mouse brain. The cytosolic sequence of LAMP2C and its affinity for RNA are evolutionarily conserved from nematodes to humans. Our findings shed light on the mechanisms underlying RNA homeostasis in higher eukaryotes.     

Lipid peroxidation modification of protein generates Nepsilon-(4-oxononanoyl)lysine as a pro-inflammatory ligand

4-Oxo-2(E)-nonenal (ONE), a peroxidation product of ω-6 polyunsaturated fatty acids, covalently reacts with lysine residues to generate a 4-ketoamide-type ONE-lysine adduct, N(ε)-(4-oxononanoyl)lysine (ONL). Using an ONL-coupled protein as the immunogen, we raised the monoclonal antibody (mAb) 9K3 directed to the ONL and conclusively demonstrated that the ONL was produced during the oxidative modification of a low density lipoprotein (LDL) in vitro. In addition, we observed that the ONL was present in atherosclerotic lesions, in which an intense immunoreactivity was mainly localized in the vascular endothelial cells and macrophage- and vascular smooth muscle cell-derived foam cells. Using liquid chromatography with on-line electrospray ionization tandem mass spectrometry, we also established a highly sensitive method for quantification of the ONL and confirmed that the ONL was indeed formed during the lipid peroxidation-mediated modification of protein in vitro and in vivo. To evaluate the biological implications for ONL formation, we examined the recognition of ONL by the scavenger receptor lectin-like oxidized LDL receptor-1 (LOX-1). Using CHO cells stably expressing LOX-1, we evaluated the ability of ONL to compete with the acetylated LDL and found that both the ONE-modified and ONL-coupled proteins inhibited the binding and uptake of the modified LDL. In addition, we demonstrated that the ONL-coupled protein was incorporated into differentiated THP-1 cells via LOX-1. Finally, we examined the effect of ONL on the expression of the inflammation-associated gene in THP-1 and observed that the ONL-coupled proteins significantly induced the expression of atherogenesis-related genes, such as the monocyte chemoattractant protein-1 and tumor necrosis factor-α, in a LOX-1-dependent manner. Thus, ONL was identified to be a potential endogenous ligand for LOX-1.     

Chemical synthesis of the 17-propanamide derivatives of stereoisomeric Δ14-17α- and 17β-estradiols: potential 17β-hydroxysteroid dehydrogenase inhibitors

The 17-propanamide derivatives of diastereomeric Δ¹⁴-17α- and 17β-estradiols, the potential candidates of a 17β-hydroxysteroid dehydrogenase (17β-HSD) inhibitor, were synthesized in 11 steps from estrone. The principal reactions employed involved in (1) conversion of estrone to the corresponding Δ¹⁴-estrone, (2) Grignard reaction of Δ¹⁴-estrone with allylmagnesium bromide followed by regioselective hydroboration of the resulting stereoisomeric 17ξ-allyl-Δ¹⁴-17ξ-ols with 9-borabicyclo[3.3.1]nonane (9-BBN), and (3) direct amidation of the 17ξ-O-/17ξ-C-spiro-γ-lactones with NH₃ under positive pressure of H₂.     

Pctaire1/Cdk16 promotes skeletal myogenesis by inducing myoblast migration and fusion

The Cdk-related protein kinase Pctaire1/Cdk16 is abundantly expressed in brain, testis and skeletal muscle. Functional roles of Pctaire1 such as regulation of neuron migration and neurite outgrowth thus far have been mainly elucidated in the field of nervous system development. Although these regulations based on cytoskeletal rearrangements evoke a possible role of Pctaire1 in the development of skeletal muscle, little is known in this regard. In this study, we demonstrated that myogenic differentiation and subsequent fusion is promoted in Pctaire1 overexpressing cells, and conversely, is inhibited in the knockdown cells. Furthermore, our findings suggest that Pctaire1 exerts promyogenic effects by regulating myoblast migration and process formation during skeletal myogenesis.     

Nox1 activation by βPix and the role of Ser-340 phosphorylation

Rac is an activating factor for Nox1, an O₂⁻-generating NADPH oxidase, expressed in the colon and other tissues. Rac requires a GDP-GTP exchange factor for activation. Nox1 activation by βPix has been demonstrated in cell lines. We examined the effects of βPix and its phosphomimetic mutant on endogenous Nox1 in Caco-2 cells transfected with Noxo1 and Noxa1. βPix expression enhanced O₂⁻ production in resting cells and cells stimulated with EGF or phorbol ester. βPix(S340E) further enhanced O₂⁻ production, while βPix(S340A) eliminated the βPix effect. βPix(S340E), but not βPix(S340A), had higher affinity and GEF activity for Rac than wild-type βPix. These results suggest that βPix phosphorylation at Ser-340 upregulates Nox1 through Rac activation, confirming Rac as a trigger for acute Nox1-dependent ROS production.