Accumulation of elements in the arteries and cardiac valves of Thai with aging

To elucidate whether the extent of element accumulation in the arteries and cardiac valves with aging was different between different races, the authors investigated the accumulation of elements in the arteries and cardiac valves of the Thai with aging and the relationships among elements in the cardiac valves. After ordinary dissection at Chiang Mai University was finished, 16 arteries and 4 cardiac valves were resected and element contents were determined by inductively coupled plasma-atomic emission spectrometry. In the 16 arteries, the average content of calcium was the highest in the site of the abdominal aorta ramifying into the common iliac arteries, and it decreased in the order internal iliac, coronary, abdominal aorta, common iliac, external iliac, superior mesenteric, inferior mesenteric, thoracic aorta, brachial, radial, common carotid, subclavian, ulnar, axillary, renal, and internal thoracic arteries. The average contents of phosphorus and magnesium in respective arteries were parallel with the average contents of calcium, except for the coronary artery. In comparison with the arteries of the Japanese, the trend of calcium accumulation in the arteries of the Thai was almost similar to that in the arteries of the Japanese, except for the coronary artery and thoracic aorta. The calcium accumulation in the coronary artery was much higher in the Thai than in the Japanese, whereas that in the thoracic aorta was lower in the Thai than in the Japanese. Regarding elements in the cardiac valves, the calcium content increased remarkably in the seventies in the aortic valve and in the nineties in the pulmonary valve, but it hardly increased in both the mitral and tricuspid valves with aging. The average content of calcium was the highest in the aortic valve, and it decreased in the order pulmonary, tricuspid, and mitral valves. Regarding the relationship among elements in the aortic valves, it was found that there were extremely significant direct correlations among the contents of calcium, phosphorus, and magnesium, whereas there were significant direct correlations between zinc and either calcium or phosphorus contents. Although significant correlations were found between sulfur and the other element contents in the aortic valves of the Japanese, no significant correlations were found between them in the aortic valves of the Thai. In the mitral valves, extremely or very significant direct correlations were found among the contents of calcium, phosphorus, magnesium, and sulfur, with some exceptions that there were no significant correlations between phosphorus and either magnesium or sulfur contents. In addition, no significant correlation was found in the calcium content between the aortic valve and coronary artery in the same individuals.     

Higher resting metabolic rate in long-lived breeding Ansell’s mole-rats (<Emphasis Type="Italic">Fukomys anselli</Emphasis>)

Background

Reproduction is an energetically expensive process that supposedly impairs somatic integrity in the long term, because resources are limited and have to be allocated between reproduction and somatic maintenance, as predicted by the life history trade-off model. The consequence of reduced investment in somatic maintenance is a gradual deterioration of function, i.e. senescence. However, this classical trade-off model gets challenged by an increasing number of contradicting studies. Here we report about an animal model, which adds more complexity to the ongoing debate. Ansell’s mole-rats are long-lived social subterranean rodents with only the founder pair reproducing, while most of their offspring remain in the parental burrow system and do not breed. Despite of a clear reproductive trade-off, breeders live up to twice as long as non-breeders, a unique feature amongst mammals.

Methods

We investigated mass-specific resting metabolic rates (msRMR) of breeders and non-breeders to gain information about the physiological basis underlying the reproduction-associated longevity in Ansell’s mole-rats. We assessed the thermoneutral zone (TNZ) for breeders and non-breeders separately by means of indirect calorimetry. We applied generalized linear mixed-effects models for repeated measurements using the msRMR in the respective TNZs.

Results

TNZ differed between reproductive and non-reproductive Ansell’s mole-rats. Contrary to classical aging models, the shorter-lived non-breeders had significantly lower msRMR within the thermoneutral zone compared to breeders.

Conclusion

This is the first study reporting a positive correlation between msRMR and lifespan based on reproductive status. Our finding contradicts common aging theories, but supports recently introduced models which do not necessarily link reproductive trade-offs to lifespan reduction.

     

Biotic elicitation at different feeding time in cell suspension cultures of Eurycoma longifolia Jack,a valuable medicinal plant,for enhancement of cytotoxic activity of bioactive compounds against human colon cancer cell line

In Vitro Cellular & Developmental Biology - Plant - The root extract of Eurycoma longifolia Jack has been shown to be effective against different type of cancers. Present study was carried out...     

Caspase-independent Cell Killing by Fas-associated Protein with Death Domain

The binding of Fas ligand to Fas recruits caspase 8 to Fas via an adaptor, FADD/MORT1, and activates a caspase cascade leading to apoptosis. Here, we describe a human Jurkat-derived cell line (JB-6) that is deficient in caspase 8. This cell line was resistant to the apoptosis triggered by Fas engagement. However, the multimerization of Fas-associated protein with death domain, through the use of a dimerizing system, killed the JB-6 cells. This killing process was not accompanied by the activation of caspases or DNA fragmentation. The dying cells showed neither condensation nor fragmentation of cells and nuclei, but the cells and nuclei swelled in a manner similar to that seen in necrosis. These results suggested that Fas-associated protein with death domain can kill the cells via two pathways, one mediated by caspases and another that does not involve them.     

Castration inhibits biliary proliferation induced by bile duct obstruction: novel role for the autocrine trophic effect of testosterone

Increased cholangiocyte growth is critical for the maintenance of biliary mass during liver injury by bile duct ligation (BDL). Circulating levels of testosterone decline following castration and during cholestasis. Cholangiocytes secrete sex hormones sustaining cholangiocyte growth by autocrine mechanisms. We tested the hypothesis that testosterone is an autocrine trophic factor stimulating biliary growth. The expression of androgen receptor (AR) was determined in liver sections, male cholangiocytes, and cholangiocyte cultures [normal rat intrahepatic cholangiocyte cultures (NRICC)]. Normal or BDL (immediately after surgery) rats were treated with testosterone or antitestosterone antibody or underwent surgical castration (followed by administration of testosterone) for 1 wk. We evaluated testosterone serum levels; intrahepatic bile duct mass (IBDM) in liver sections of female and male rats following the administration of testosterone; and secretin-stimulated cAMP levels and bile secretion. We evaluated the expression of 17β-hydroxysteroid dehydrogenase 3 (17β-HSD3, the enzyme regulating testosterone synthesis) in cholangiocytes. We evaluated the effect of testosterone on the proliferation of NRICC in the absence/presence of flutamide (AR antagonist) and antitestosterone antibody and the expression of 17β-HSD3. Proliferation of NRICC was evaluated following stable knock down of 17β-HSD3. We found that cholangiocytes and NRICC expressed AR. Testosterone serum levels decreased in castrated rats (prevented by the administration of testosterone) and rats receiving antitestosterone antibody. Castration decreased IBDM and secretin-stimulated cAMP levels and ductal secretion of BDL rats. Testosterone increased 17β-HSD3 expression and proliferation in NRICC that was blocked by flutamide and antitestosterone antibody. Knock down of 17β-HSD3 blocks the proliferation of NRICC. Drug targeting of 17β-HSD3 may be important for managing cholangiopathies.     

Inhibition of tubulin-dependent ATPase activity in microtubule proteins from porcine brain by S100 protein

Microtubule-associated proteins (MAPs) of brain microtubules exhibit an ATPase activity which is markedly enhanced by tubulin and Ca²⁺. Addition of S100 protein decreased the tubulindependent Ca²⁺-ATPase activity by about 85%, but did not affect the activity without tubulin. The inhibition by S100 protein was concentration-dependent and the apparent K_m value for ATP was not altered. A large amount of tubulin restored the inhibition, indicating that S100 protein acts through the binding to the tubulin molecule. Zn²⁺, which can bind both microtubule proteins and S100 protein, had little effect on the inhibitory action of S100 protein. The ATPase inhibition by S100 protein was partially restored by chlorpromazine or vinblastine. S100a is more effective than S100b on the inhibitory effect of tubulin-dependent ATPase activity. The results suggest that S100 protein may function as a regulatory factor of ATPase in brain microtubules.     

Cooperative assembly of beta-barrel pore-forming toxins

Bacterial beta-barrel pore-forming toxins are secreted as water-soluble monomeric proteins and assemble into beta-barrel-shaped pores/channels through membranes of target cells, causing cell death and lysis. The pore assemblies that undergo various intermediate stages are symbolized by the association of multi-subunit structures in cells. Crystal structures of water-soluble monomers and membrane-embedded oligomeric pores, and recent studies involving biochemical detection and direct visualization of the sequential assembly of the toxin monomers have solved the mystery of how the pores are formed. Here, we review the mechanism of the cooperative assembly of several toxins of interest to explain the nature of the activities of the toxins.     

High-resolution mapping of zym, a recessive gene for Zucchini yellow mosaic virus resistance in cucumber

Key message

Using a high-resolution mapping approach, we identified a candidate gene for ZYMV resistance in cucumber. Our findings should assist the development of high-versatility molecular markers for MAS for ZYMV resistance.

Abstract

Zucchini yellow mosaic virus (ZYMV) causes significant disease, which leads to fruit yield loss in cucurbit crops. Since ZYMV resistance is often inherited recessively in cucumber, marker-assisted selection (MAS) is a useful tool for the development of resistant cucumber cultivars. Using 128 families of an F_2:3 population derived from a cross between susceptible ‘CS-PMR1’ and resistant ‘A192-18’ cucumber inbred lines, we confirmed that ZYMV resistance is conferred by a single recessive locus: zym ^A192-18 . We constructed a cucumber genetic linkage map that included 125 simple sequence repeat (SSR) markers segregating into 7 linkage groups (chromosomes). The zym ^A192-18 locus was mapped to chromosome 6, at genetic distances of 0.9 and 1.3 cM from two closely linked SSR markers. For high-resolution genetic mapping, we identified new molecular markers cosegregating with the zym ^A192-18 locus; using cucumber genomic and molecular marker resources and screening an F₂ population of 2,429 plants, we narrowed down the zym ^A192-18 locus to a <50-kb genomic region flanked by two SSR markers, which included six candidate genes. Sequence analysis of the candidate genes’ coding regions revealed that the vacuolar protein sorting-associated protein 4-like (VPS4-like) gene had two SNPs between the parental lines. Based on SNPs of the VPS-4-like gene, we developed zym ^A192-18 -linked DNA markers and found that genotypes associated with these markers were correlated with the ZYMV resistance phenotype in 48 cucumber inbred lines. According to our data, the gene encoding VPS4-like protein is a candidate for the zym ^A192-18 locus. These results may be valuable for MAS for ZYMV resistance in cucumber.     

Pathway-specific metabolome analysis with <Superscript>18</Superscript>O<Subscript>2</Subscript>-labeled <Emphasis Type="Italic">Medicago truncatula</Emphasis> via a mass spectrometry-based approach

Introduction

Oxygen from carbon dioxide, water or molecular oxygen, depending on the responsible enzyme, can lead to a large variety of metabolites through chemical modification.

Objectives

Pathway-specific labeling using isotopic molecular oxygen (¹⁸O₂) makes it possible to determine the origin of oxygen atoms in metabolites and the presence of biosynthetic enzymes (e.g., oxygenases). In this study, we established the basis of ¹⁸O₂-metabolome analysis.

Methods

¹⁸O₂ labeled whole Medicago truncatula seedlings were prepared using ¹⁸O₂-air and an economical sealed-glass bottle system. Metabolites were analyzed using high-accuracy and high-resolution mass spectrometry. Identification of the metabolite was confirmed by NMR following UHPLC–solid-phase extraction (SPE).

Results

A total of 511 peaks labeled by ¹⁸O₂ from shoot and 343 peaks from root were annotated by untargeted metabolome analysis. Additionally, we identified a new flavonoid, apigenin 4′-O-[2′-O-coumaroyl-glucuronopyranosyl-(1–2)-O-glucuronopyranoside], that was labeled by ¹⁸O₂. To the best of our knowledge, this is the first report of apigenin 4′-glucuronide in M. truncatula. Using MSⁿ analysis, we estimated that ¹⁸O atoms were specifically incorporated in apigenin, the coumaroyl group, and glucuronic acid. For apigenin, an ¹⁸O atom was incorporated in the 4′-hydroxy group. Thus, non-specific incorporation of an ¹⁸O atom by recycling during one month of labeling is unlikely compared with the more specific oxygenase-catalyzing reaction.

Conclusion

Our finding indicated that ¹⁸O₂ labeling was effective not only for the mining of unknown metabolites which were biosynthesized by oxygenase-related pathway but also for the identification of metabolites whose oxygen atoms were derived from oxygenase activity.