Assessing Molecular Localization of Symbiont Microalgae in Coral Branches Through Mass Spectrometry Imaging

Reef-building corals are a fundamental pillar of coral reef ecosystems in tropical and subtropical shallow environments. Corals harbor symbiotic dinoflagellates belonging to the family Symbiodiniaceae, commonly known as zooxanthellae. Extensive research has been conducted on this symbiotic relationship, yet the fundamental information about the distribution and localization of Symbiodiniaceae cells in corals is still limited. This information is crucial to understanding the mechanism underlying the metabolite exchange between corals and their algal symbionts, as well as the metabolic flow within holobionts. To examine the distribution of Symbiodiniaceae cells within corals, in this study, we used fluorescence imaging and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MS-Imaging) on branches of the Acropora tenuis coral. We successfully prepared frozen sections of the coral for molecular imaging without fixing or decalcifying the coral branches. By combining the results of MS-Imaging with that of the fluorescence imaging, we determined that the algal Symbiodiniaceae symbionts were not only localized in the tentacle and surface region of the coral branches but also inhabited the in inner parts. Therefore, the molecular imaging technique used in this study could be valuable to further investigate the molecular dynamics between corals and their symbionts.

Adverse Drug Event Profile Associated with Anti-dementia Drugs: Analysis of a Spontaneous Reporting Database

Adverse drug events (ADEs) rates associated with anti-dementia acetylcholinesterase inhibitors are estimated to be 5%-20% and show a wide range of symptoms. No report has examined whether there is a difference in the anti-dementia drugs' ADEs profile. This study aimed to establish whether anti-dementia drugs' ADEs profile differed. Data was based on the Japanese Adverse Drug Event Report (JADER) database. The reporting odds ratios (RORs) was used to analyze data for ADEs from April 2004-October 2021. The target drugs were donepezil, rivastigmine, galantamine, and memantine. The top ten most frequently occurring adverse events were selected. The association between the RORs and antidementia drug ADEs was evaluated, and compared the distribution rate of expression age related to ADEs and each ADEs' timing of onset due to anti-dementia drugs. The primary outcome was RORs. Secondary outcome were expression age and time-to-onset of ADE associated with anti-dementia drugs. A total of 705,294 reports were analyzed. The adverse events incidence differed. Bradycardia, loss of consciousness, falls, and syncope incidence were significantly diverse. The Kaplan-Meier curve results for the cumulative ADEs incidence showed that donepezil had the slowest onset, while galantamine, rivastigmine, and memantine had approximately the same timing of onset.

Desorption electrospray ionization-mass spectrometry imaging of carnitine and imidazole dipeptides in pork chop tissues

Carnitine is essential for energy production and lipid metabolism in skeletal muscle. Carnosine and its methylated analogs anserine and balenine are histidine-containing imidazole dipeptides, which are antioxidative compounds. They are major health-related components in meat; however, analytical technique to investigate their distribution among tissues have not fully established. Here, we performed desorption electrospray ionization (DESI)-mass spectrometry imaging (MSI) of pork chop sections containing longissimus thoracis et lumborum muscle (loin), intermuscular fat tissue, transparent tissue, and spinalis muscle to investigate the distributions of carnitine and imidazole dipeptides. Liquid chromatography-MS revealed that the concentrations of carnitine, carnosine, anserine, and balenine were 11.0 ± 0.9, 330.1 ± 15.5, 21.2 ± 1.5, and 9.6 ± 0.5 mg/100 g, respectively. In the mass spectrum obtained by DESI-MSI, peaks corresponding to the chemical formulae of carnitine and imidazole dipeptides were detected. DESI-MSI provided definite identification of carnitine, while DESI-tandem MSI (MS/MSI) was necessary to accurately visualize carnosine, anserine, and balenine. Carnitine and these imidazole dipeptides were mainly distributed in the loin and spinalis muscle, while their distribution was not uniform in both muscle tissues. In addition, the balance between both tissues were different. The concentration of carnitine was higher in the spinalis muscle than that in the loin, while those of imidazole dipeptides were higher in the loin than those in the spinalis muscle. These results were consistent with those obtained by liquid chromatography-MS quantification, suggest that DESI-MSI analysis is useful for the distribution analysis of carnitine and imidazole dipeptides in meat.

Low-dose ethanol increases aflatoxin production due to the adh1-dependent incorporation of ethanol into aflatoxin biosynthesis

Aflatoxins are toxic secondary metabolites produced by some aspergilli, including Aspergillus flavus. Recently, ethanol has attracted attention as an agent for the control of aflatoxin contamination. However, as aflatoxin biosynthesis utilizes acetyl coenzyme A, ethanol may be conversely exploited for aflatoxin production. Here, we demonstrated that not only the ¹³C of labeled ethanol, but also that of labeled 2-propanol, was incorporated into aflatoxin B₁ and B₂, and that ethanol and 2-propanol upregulated aflatoxin production at low concentrations (<1% and <0.6%, respectively). In the alcohol dehydrogenase gene adh1 deletion mutant, the ¹³C incorporation of labeled ethanol, but not labeled 2-propanol, into aflatoxin B₁ and B₂ was attenuated, indicating that the alcohols have different utilization pathways. Our results show that A. flavus utilizes ethanol and 2-propanol as carbon sources for aflatoxin biosynthesis and that adh1 indirectly controls aflatoxin production by balancing ethanol production and catabolism.

Eicosapentaenoic acid is associated with the attenuation of dysfunctions of mesenchymal stem cells in the abdominal aortic aneurysm wall

Abdominal aortic aneurysm (AAA) is a vascular disease characterized by progressive dilation of the aorta which is reportedly associated with inflammation. Previous studies suggested that eicosapentaenoic acid (EPA) has suppressive effects on AAA development via anti-inflammatory activities. However, relationships between the anti-inflammatory effects and the cells in the AAA wall are poorly understood. In this study, we visualized the distribution of EPA-containing phosphatidylcholine (EPA-PC) in the AAA wall. EPA-PC was not ubiquitously distributed in both animal (hypoperfusion-induced AAA model) and human AAA walls, suggesting the preferential incorporation of EPA into certain cells. In the EPA-PC-high region of both animal and human AAAs, mesenchymal stem cell (MSC) marker positive areas were significantly higher than those in the EPA-PC-low region. Matrix metalloproteinase-positive MSCs were significantly lower in the AAA wall of the animal model which was administered EPA-rich fish oil. These data suggest that EPA is associated with the attenuation of MSC dysfunctions, which result in the suppression of AAA development.

Distribution analysis of jasmonic acid-related compounds in developing Glycine max L. (soybean) seeds using mass spectrometry imaging and liquid chromatography-mass spectrometry

INTRODUCTION

Jasmonic acid (JA) and its precursors are oxylipins derived from α-linolenic acid (αLA) and hexadecatrienoic acid, and regulate seed development. However, their spatial distribution in the developing Glycine max L. (soybean) seeds has not been elucidated.

OBJECTIVE

To investigate the distribution of JA-related compounds in the developing soybean seeds using desorption electrospray ionisation-mass spectrometry imaging (DESI-MSI) and liquid chromatography-electrospray ionisation-mass spectrometry (LC-ESI-MS) analyses.

METHODS

Cryosections of developing seeds were prepared using adhesive films, and subjected to DESI-MSI analysis. Verification of the DESI-MSI ion images were performed using DESI-tandem MSI (MS/MSI), LC-ESI-MS and tandem MS (MS/MS).

RESULTS

In the DESI-MSI mass spectrum, peaks matching the chemical formulae of αLA, 12-oxo-phytodienoic acid (OPDA), and 3-oxo-2-(2-(Z)-pentenyl)-cyclopentane-1-octanoic acid (OPC-8:0) were detected. These compounds were mainly distributed in the seed coat, especially near the hilum. This was consistent with the quantitative results obtained by LC-ESI-MS. While, DESI-MS/MSI and LC-ESI-MS/MS suggested the presence of isomers for OPDA and OPC-8:0. The effect of isomers on the DESI-MSI ion images was small for OPDA, and considerable for OPC-8:0.

CONCLUSION

These results demonstrated that free αLA, OPDA, and OPC-8:0 were the abundant JA-related compounds mainly distributed in the seed coat of the developing soybeans. OPDA and OPC-8:0 might exert a biological role in the seed coat. To the best of my knowledge, this is the first report on the accumulation of OPDA and OPC-8:0 in the seed coat. The combination of DESI-MSI and LC-ESI-MS is a useful tool for distribution analysis of JA-related compounds in the developing seeds.

Unique distribution of ellagitannins in ripe strawberry fruit revealed by mass spectrometry imaging

Ellagitannins (ETs) are hydrolysable tannins composed of a polyol core, primarily glucose, which is esterified with hexahydroxydiphenic acid (HHDP), and in some cases, gallic acid. ETs are the major phenolic compounds found in strawberries and may contribute to the health-related properties of strawberries, because of their strong antioxidative activity. However, their distribution in the strawberry fruit remains unclear. In this study, matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI–MSI) was used to visualize ETs in ripe strawberry fruits. Five peaks, corresponding to the m/z values of ET [M−H]⁻ ions detected in the MALDI–MS spectrum of strawberry extracts, were identified as strictinin, pedunculagin, casuarictin, davuriicin M₁, and an unknown ET using MALDI–tandem MS (MS/MS). In addition, liquid chromatography–electrospray ionization–MS/MS of the extracts revealed the presence of pedunculagin isomers and the unknown ET. Ion images of these five ETs were reconstructed using MALDI–MSI. Strictinin was widely distributed in and around the achene seed coats, while the other ETs were dispersed in and around the seed coats, and at the bottom of the receptacle; pedunculagin was distributed in the epidermis and pith, whereas casuarictin, the unknown ET, and davuriicin M₁ were distributed in the pith. Moreover, MALDI–MSI of a casuarictin standard indicated that in-source fragmentation weakly affected the ion images. The results suggest that the distribution of ETs depends on the presence or absence of their constituents, namely galloyl units, HHDP, and bis-HHDP. To the best of my knowledge, this is the first report on the visualization of ETs in plant tissues using MSI, MALDI–MSI may be a useful tool for analyzing the distribution of ETs in the strawberry fruit.

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The ellagitannins (ETs) in strawberry fruits were identified.

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MALDI-MS/MS and LC-MS/MS were used.

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The ETs identified in the fruits were visualized using MALDI-MSI.

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The ETs showed unique distributions in the seeds and the lower receptacle.

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The distribution of ETs depends on their constituents: galloyl units and HHDP.

Unique localization of jasmonic acid-related compounds in developing Phaseolus vulgaris L. (common bean) seeds revealed through desorption electrospray ionization-mass spectrometry imaging

Jasmonic acid (JA) and its precursors are oxylipins derived from α-linolenic acid (αLA). Presumably, they are involved in the regulation of seed embryogenesis, dormancy, and germination. However, their spatial localization in the developing Phaseolus vulgaris L. (common bean) seeds has not been fully elucidated. Therefore, desorption electrospray ionization-mass spectrometry imaging (DESI-MSI) was performed to investigate their localization in the developing seeds. Peaks corresponding to the chemical formulae of αLA and 3-oxo-2-(2-(Z)-pentenyl)-cyclopentane-1-octanoic acid (OPC-8:0) were localized mainly in the radicle and seed coat, while that of 12-oxo-phytodienoic acid (OPDA) in the seed coat. This was consistent with the quantitative results obtained using liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) analysis. In contrast, DESI-tandem MSI (MS/MSI) and LC-ESI-MS/MS analyses showed that the effects of isomers on the DESI-MSI ion images were small for αLA and OPDA, but not for OPC-8:0. This indicated that DESI-MSI could accurately visualize αLA and OPDA, while DESI-MS/MSI was necessary to visualize OPC-8:0. The results demonstrated that free αLA and OPC-8:0 were abundant in the radicle and seed coat, while free OPDA was accumulated in the seed coat. Interestingly, the localization pattern of OPDA was similar to that of JA. In addition, compared to the concentrations of OPDA, the concentration of OPC-8:0 was lower in the seed coat and higher in the radicle. These results suggest that OPDA and/or JA play a biological role mainly in the seed coat, while OPC-8:0 is biologically active mainly in the radicle. Therefore, DESI-MSI coupled with LC-ESI-MS is a useful tool for spatial analysis of JA-related compounds in developing common bean seeds.

Spatial Analysis of Phosphatidylinositol Molecular Species in Pork Chop Tissues Using Matrix-assisted Laser Desorption/ionization-Mass Spectrometry Imaging

Matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) is a powerful technique for visualizing lipids in biological tissues. Phosphatidylinositol (PI), a phospholipid in pork, is a major source of inositol in animal-derived foods believed to be protective against diseases related to pregnancy and cancer. However, the distribution of PI molecular species in pork is not well understood. Here, we performed MALDI-MSI analysis to investigate the distribution and composition of PI molecular species in pork chop comprising Longissimus thoracis et lumborum muscle (loin), intermuscular fat tissue, transparent tissue, and spinalis muscle. Twelve diacyl-PI molecular species were identified using liquid chromatography-electrospray ionization-tandem mass spectrometry (MS/MS) and MALDI-MS/MS analysis and visualized using MALDI-MSI. Spinalis muscle had the highest amount of identified PI molecular species, followed by loin, transparent tissue, and intermuscular fat tissue. The diacyl-PI molecular species containing hexadecadienoic, oleic, linoleic and eicosadienoic acids at the sn-2 position were mainly abundant in the loin and spinalis muscle, whereas those containing mead, arachidonic, docosatetraenoic, and docosapentaenoic acids at the sn-2 position were mainly abundant in both muscles as well as transparent tissues. Notably, the balance of PI molecular species differed among the tissues depending on fatty acid compositions at the sn-2 position. These results suggested that MALDI-MSI is a promising tool for assessing the association between individual pork tissues and the protective effects of PI molecular species against diseases related to pregnancy and cancer. To the best of our knowledge, this is the first report showing tissue-specific distributions of PI molecular species in pork chop using MALDI-MSI.

Similar distribution of orally administered eicosapentaenoic acid and M2 macrophage marker in the hypoperfusion-induced abdominal aortic aneurysm wall

Abdominal aortic aneurysm (AAA) is an aortic disease in which the aortic diameter is ≥3.0 cm; if left untreated, the aortic wall continues to weaken, resulting in progressive dilatation. Effective therapeutic drugs for AAA patients have not been discovered. Eicosapentaenoic acid (EPA) reportedly attenuates the development of AAA in experimental AAA animal models. However, the underlying mechanism of action is still not totally clear. To understand the mechanism, we visualized the distribution of EPA-containing phosphatidylcholine (PC) in the AAA wall by matrix-assisted laser desorption ionization-mass spectrometry imaging. EPA-containing PC was characteristically distributed in the AAA wall, and the positive area for the M2 macrophage marker was significantly higher in the region where EPA-containing PC was highly detected (region 2) than in the region where EPA-containing PC was poorly detected (region 1). The M1 macrophage marker levels were not different between regions 1 and 2. A comparative observation showed a similar distribution of the M2 macrophage marker and EPA-containing PC. These data suggest the preferential incorporation of EPA into M2 macrophages. Positive areas for matrix metalloproteinase 2 and malondialdehyde in region 2 were significantly lower than those in region 1. The reported suppressive effect of EPA on the development of AAA may be partly attributed to the increased anti-inflammatory property of M2 macrophages.

Adhesive film applications help to prepare strawberry fruit sections for desorption electrospray ionization-mass spectrometry imaging

Desorption electrospray ionization-mass spectrometry imaging (DESI-MSI) is a powerful tool to analyze the distribution of metabolites in biological tissues. Cryosectioning of biological tissues is usually required prior to DESI-MSI, but it can be difficult for tissues that are fragile, hard, and have a high-water content. The Kawamoto method uses transparent adhesive films to prepare cryosections; however, its application for plant tissues, such as strawberry tissues, in DESI-MSI has not been verified. In this study, strawberry cryosections maintained original structures were prepared using adhesive film. Subsequently, numerous peaks were detected for the sections using the positive and negative ion modes of DESI-MSI. Several primary and specialized metabolites, such as amino acids, sugars, organic acids, and flavonoids, were identified and visualized. These results suggest the use of adhesive films when cryosectioning could improve DESI-MSI analysis of the metabolites in strawberry fruits and various tissues of other plant species.

Direct LC–ESI–MS/MS analysis of plant glucosylceramide and ceramide species with 8E and 8Z isomers of the long chain base

Glucosylceramides and ceramides with 8E and 8Z isomers of the long chain base are found in plants. These isomers have been difficult to quantify separately using liquid chromatography–tandem mass spectrometry (LC–MS/MS) because the isomers have the same retention time, their precursor and product ions have the same m/z values, and plant ceramide standards are not commercially available. Here we tested trial separations using various ODS columns and prepared plant ceramide standards generated by human glucocerebrosidase (imiglucerase) using commercially available plant glucosylceramide standards as the substrates. Consequently, we were able to quantify the isomers based on differences in retention times in a TSKgel ODS-120A column (Tosoh, Tokyo Japan) using LC–electrospray ionization–MS/MS (LC–ESI–MS/MS).

Mass Spectrometry Imaging of Flavonols and Ellagic Acid Glycosides in Ripe Strawberry Fruit

Flavonols and ellagic acid glycosides are major phenolic compounds in strawberry fruit. They have antioxidant activity, show protective functions against abiotic and biotic stress, and provide health benefits. However, their spatial distribution in ripe fruit has not been understood. Therefore, matrix-assisted laser desorption/ionization (MALDI)-mass spectrometry imaging (MSI) was performed to investigate their distribution in fruit tissues. Using strawberry extract, five flavonols, namely, three kaempferols and two quercetins, and two ellagic acid glycosides, were tentatively identified by MALDI-tandem MS. To investigate the tentatively identified compounds, MALDI-MSI and tandem MS imaging (MS/MSI) analyses were performed. Kaempferol and quercetin glycosides showed similar distribution patterns. They were mainly found in the epidermis, while ellagic acid glycosides were mainly found in the achene and in the bottom area of the receptacle. These results suggested that the difference in distribution pattern between flavonols and ellagic acid glycosides depends on the difference between their aglycones. Seemingly, flavonols play a role in protective functions in the epidermis, while ellagic acid glycosides play a role in the achene and in the bottom side of the receptacle, respectively. These results demonstrated that MALDI-MSI is useful for distribution analysis of flavonols and ellagic acid glycosides in strawberry fruit.

Effects of whey protein hydrolysate on growth promotion and immunomodulation in mouse pups in artificial rearing system

This study aimed to investigate the effects of whey protein hydrolysate (WPH) on the growth and immunity of mouse pups in artificial rearing (AR) system. Mouse pups were reared in the AR system with artificial milk including 5% WPH (AR with WPH) or not (AR without WPH), and the remaining pups were reared by their mother (dam) for 14 days after birth. The body weight change and body weight gain rates in the AR with WPH group were significantly higher than those observed in the AR without WPH group and similar to those in the dam group. Moreover the feed and protein efficiencies in the AR with WPH group were significantly higher than those of the AR without WPH group. In addition, the supplement of WPH in the AR system was shown to significantly elevate the number of CD3⁺ CD8⁺ , B220⁺ CD19⁺ , IA/IE⁺ CD11c⁺ , and CD11b⁺ in the thymocyte and/or splenocyte, and the thymus weight. Furthermore, MALDI-TOF/MS analysis identified the amino acid sequences corresponding to some peptides, and indicated that VRTPEVDDE had the highest relative intensity among the peptides from tested WPH. Therefore, WPH would be required to not only promote growth, but also exert immunomodulatory activities in mouse pups in AR system.

Isolation, Evaluation, and Identification of Angiotensin I-Converting Enzyme Inhibitory Peptides from Game Meat

Game meat has been underutilized, while it offers the potential to diversify not only the human diet but also increase food production and the nutritional value of meat products. This study aimed to determine the angiotensin I-converting enzyme (ACE) inhibitory activities of the digested game meats (venison and boar meat) compared with those of livestock meats (beef and pork). Through the sodium dodecyl sulfate polyacrylamide gel electrophoresis and size chromatography results, we found that the digested products from each meat had different molecular weights. The ACE inhibitory ratio in all tested samples had gradually increased following by the enzyme treatments. ACE inhibitory ratios and the half maximal inhibitory concentration values indicated that digested venison was the most potent inhibitor of ACE activity, followed by the digested boar meat. The level of anserine in digested venison was higher than that in the other meats, but the carnosine level was lower. Through fractionations and liquid chromatography-tandem mass spectrometry analysis, five ACE inhibitory peptides were identified from the digested venison. Of these peptides, Isoleucine-Lysine- Glutamic Acid-Valine-Threonine-Glutamic Acid-Arginine (IKEVTER) demonstrated the highest ACE inhibitory activity. Therefore, the game meat is food that is believed potentially to offer high bioactivities, particularly antihypertensive forces.

Localization of Flavan-3-ol Species in Peanut Testa by Mass Spectrometry Imaging

Flavan-3-ols, procyanidins and their monomers are major flavonoids present in peanuts that show a wide range of biological properties and health benefits, based on their potent antioxidant activity. Procyanidin oligomers, especially A-type, are reportedly abundant in peanut skin; however, their localization in the raw peanut testa remains poorly understood. Therefore, we performed matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) to investigate the localization of flavan-3-ols in peanut testa. 1,5-Diaminonaphthalene was coated onto the peanut section by matrix vapor deposition/recrystallization, and MALDI-MSI measurements were performed in the negative-ion mode. Peaks matching the m/z values of flavan-3-ol [M - H]^- ions were observed in the mass spectrum extracted from the outer epidermis of the peanut testa, using the region of interest function. Catechin and/or epicatechin, five A-type, and one B-type procyanidins were assigned by the fragment ions generated by retro-Diels-Alder, heterocyclic ring fission, and quinone methide reactions detected in MALDI-tandem MS spectra. These flavan-3-ols were localized in the outer epidermis of the peanut testa. This information will contribute to improving the extraction and purification efficiencies of flavan-3-ols from peanut testa. As flavan-3-ols display anti-microbial activity, it is speculated that flavan-3-ols present in the outer epidermis of peanut testa act to prevent pathogen infection.

Novel Blotting Method for Mass Spectrometry Imaging of Metabolites in Strawberry Fruit by Desorption/Ionization Using Through Hole Alumina Membrane

Mass spectrometry imaging (MSI) using matrix-assisted laser desorption/ionization (MALDI) is a powerful technique for visualizing metabolites in the strawberry fruit. During sample preparation for MALDI-MSI, sectioning of the samples is usually required. In general, MALDI-MSI analysis of strawberry fruits that are larger than a single glass slide is difficult because thin sections cannot be prepared. In this study, we attempted to visualize metabolites in large strawberry fruits by MSI, employing a blotting method that uses desorption ionization using a through-hole alumina membrane (DIUTHAME) chip. Large strawberry fruits were cut and a DIUTHAME chip was set on the cross-section to blot the metabolites. After drying the DIUTHAME chip, the metabolites were measured in positive and negative ion modes using a commercial MALDI-type mass spectrometer. Several peaks were detected in both the ion modes. Various metabolites related to food quality, such as sugars, organic acids, and anthocyanins, were detected and successfully visualized by blotting on a DIUTHAME chip in MSI. These results suggest that blotting using a DIUTHAME chip in MSI is useful for visualizing the metabolites present in the strawberry fruit.

Unique Distribution of Diacyl-, Alkylacyl-, and Alkenylacyl-Phosphatidylcholine Species Visualized in Pork Chop Tissues by Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry Imaging

Phosphatidylcholine (PC) is the major phospholipid in meat and influences meat qualities, such as healthiness. PC is classified into three groups based on the bond at the sn-1 position: Diacyl, alkylacyl, and alkenylacyl. To investigate their composition and distribution in pork tissues, including longissimus thoracis et lumborum (loin) spinalis muscles, intermuscular fat, and transparent tissues, we performed matrix-assisted laser desorption/ionization–mass spectrometry imaging (MALDI–MSI). Eleven diacyl-, seven alkylacyl-, and six alkenylacyl-PCs were identified using liquid chromatography (LC)-tandem MS (MS/MS) analysis. Despite many alkylacyl- and alkenylacyl-PC species sharing identical m/z values, we were able to visualize these PC species using MALDI–MSI. Diacyl- and alkylacyl- and/or alkenylacyl-PC species showed unique distribution patterns in the tissues, suggesting that their distribution patterns were dependent on their fatty acid compositions. PCs are a major dietary source of choline in meat, and the amount was significantly higher in the muscle tissues. Consumption of choline mitigates age-related memory decline and neurodegenerative diseases; therefore, the consumption of pork muscle tissues could help to mitigate these diseases. These results support the use of MALDI–MSI analysis for assessing the association between PC species and the quality parameters of meat.

Distribution of Flavan-3-ol Species in Ripe Strawberry Fruit Revealed by Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry Imaging

Flavan-3-ols, which comprise proanthocyanidins and their monomers, are major flavonoids in strawberries, and they have a wide range of biological activities and health benefits. However, their spatial distribution in strawberry fruit remains poorly understood. Therefore, we performed matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI), to visualize flavan-3-ols in ripe strawberry fruit. Peaks matching the m/z values of flavan-3-ols [M − H]⁻ ions were detected in the negative ion mode using 1,5-diaminonaphthalene as matrix. Catechin and/or epicatechin, three B-type procyanidins, and two B-type propelargonidins were identified by MALDI-tandem MS. These flavan-3-ols were mainly distributed in the calyx, in and around the vascular bundles, and in the skin. In-source fragmentation of proanthocyanidins was determined using their standards, suggesting their distribution was mixed ion images of themselves, and fragment ions generated from those had a higher degree of polymerization. B-type procyanidins were predominantly distributed in the vascular bundles than in the skin, whereas B-type propelargonidins were almost equally distributed between the vascular bundles and skin, suggesting that their distribution patterns are different from the type of their flavan-3-ol monomers. Flavan-3-ols, especially B-type procyanidins, may help prevent pathogen infection not only in the skin but also in and around the vascular bundles.

Tissue-Specific Distribution of Sphingomyelin Species in Pork Chop Revealed by Matrix-Assisted Laser Desorption/Ionization-Imaging Mass Spectrometry

Sphingomyelin (SM) species are major sphingolipids in pork meat that affect quality parameters, such as health benefits due to their protective properties against chronic diseases; however, their spatial distribution remains unclear. We used matrix-assisted laser desorption/ionization (MALDI)-imaging mass spectrometry (IMS) to investigate the distribution and composition of SM species in pork chop consisting of longissimus thoracis et lumborum muscle (loin), intermuscular fat tissue, transparent tissue, and spinalis muscle. Four SM species were identified by liquid chromatography-electrospray ionization-tandem MS (MS/MS) and MALDI-MS/MS and visualized using MALDI-IMS. SM species containing stearic acid were predominantly distributed in the loin and spinalis muscle, whereas SM species containing palmitic, lignoceric, and nervonic acids were predominantly distributed in transparent tissue. These results indicated that the distribution of SM species differed among the pork tissues, depending on the tissue-specific fatty acid composition. The total amount including all identified SM species was higher in the loin than in spinalis muscle. Pork is reportedly associated with increased risk for chronic diseases due to the high amount of heme iron. From the observation of color, the amount of heme iron was lower in loin than in spinalis muscle. Thus, the degree of risk for chronic diseases might be lower in the loin than in spinalis muscle. This is the first report on the tissue-specific distribution of SM species in meat at a microscopic resolution using IMS. MALDI-IMS analysis may be useful in assessing the association between SM species and quality parameters of pork meat. PRACTICAL APPLICATION: Sphingomyelin (SM) species are major sphingolipids in pork meat. SM species affect quality parameters such as health benefits due to their protective properties against colon cancer and atherosclerosis. Matrix-assisted laser desorption/ionization-imaging mass spectrometry analysis combined with liquid chromatography-electrospray ionization-tandem mass spectrometry is a suitable method to directly investigate the distribution and composition of SM species at microscopic level among different tissues of pork meat. Therefore, this method is useful to assess the SM species-induced health effect of different tissues of pork meat.

Derivatization for detection of abscisic acid and 12-oxo-phytodienoic acid using matrix-assisted laser desorption/ionization imaging mass spectrometry

RATIONALE

Abscisic acid (ABA) and 12-oxo-phytodienoic acid (OPDA) play crucial roles in seed development. However, because of their low ionization efficiencies, visualization by matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) has been difficult. In this study, we used on-tissue chemical derivatization (OTCD) with the derivatization reagent Girard's T (GirT) in MALDI-IMS to visualize ABA and OPDA.

METHODS

Immature Phaseolus vulgaris L. seeds were homogenized, and frozen homogenate sections were prepared using a cryostat. The concentration of the trifluoroacetic acid (TFA) and spray volume of the GirT solution were optimized using the homogenate sections. Immature seed sections were prepared using a cryostat, and the OTCD efficiency under optimal conditions was measured using liquid chromatography/tandem mass spectrometry (LC/MS/MS). The GirT solution was sprayed on the seed sections, and then MALDI-IMS was performed.

RESULTS

The optimal TFA concentration and spray volume were 2% and 500 μL, respectively. The OTCD efficiency rates were 61 ± 10% for ABA and 45 ± 5% for OPDA. The peaks corresponding to GirT-derivatized ABA (ABA-GirT) and OPDA (OPDA-GirT) standards were detected on the optimal OTCD-treated seed sections. ABA-GirT was mainly distributed in the embryo, while OPDA-GirT was localized in the external structures. These results are in agreement with our previously published results.

CONCLUSIONS

Our results show that ABA and OPDA in the immature seeds were exactly visualized using OTCD with GirT in MALDI-IMS. Therefore, OTCD with GirT in MALDI-IMS is a promising technique for future research on the biological roles of ABA and OPDA in various immature seeds.

Distribution Analysis of Anthocyanins, Sugars, and Organic Acids in Strawberry Fruits Using Matrix-Assisted Laser Desorption/Ionization-Imaging Mass Spectrometry

Anthocyanins, sugars, and organic acids contribute to the appearance, health benefits, and taste of strawberries. However, their spatial distribution in the ripe fruit has been fully unrevealed. Therefore, we performed matrix-assisted laser desorption/ionization, MALDI-IMS, analysis to investigate their spatial distribution in ripe strawberries. The detection sensitivity was improved by using the TM-Sprayer for matrix application. In the receptacle, pelargonidins were distributed in the skin, cortical, and pith tissues, whereas cyanidins and delphinidins were slightly localized in the skin. In the achene, mainly cyanidins were localized in the outside of the skin. Citric acid was mainly distributed in the upper and bottom side of cortical tissue. Although hexose was distributed almost equally throughout the fruits, sucrose was mainly distributed in the upper side of cortical and pith tissues. These results suggest that using the TM-Sprayer in MALDI-IMS was useful for microscopic distribution analysis of anthocyanins, sugars, and organic acids in strawberries.

Low incidence of hepatitis B virus reactivation and subsequent hepatitis in patients with chronic hepatitis C receiving direct-acting antiviral therapy

To determine the clinical characteristics of hepatitis B virus (HBV) reactivation in patients undergoing interferon-free antihepatitis C virus (HCV) therapy, we examined HBV DNA in 25 HBV co-infected patients and 765 patients with resolved HBV infection during and after treatment with direct-acting antiviral agents (DAAs). Among those with HCV genotype 1, asunaprevir plus daclatasvir was administered to 160 patients, sofosbuvir (SOF) plus ledipasvir to 438 patients and paritaprevir plus ombitasvir and ritonavir to 25 patients. In total, 167 patients with genotype 2 were treated with SOF plus ribavirin. Three patients with an HBV DNA level ≥2000 IU/mL were treated with entecavir before anti-HCV therapy, without reactivation of HBV. In 3 of 22 (12%) HBV surface antigen (HBsAg)-positive patients with an HBV DNA level <2000 IU/mL, the viral load increased during treatment. However, hepatitis flare did not occur in these patients. There was no significant difference in clinical history between patients with and without HBV reactivation. Among 765 patients with resolved HBV infection, HBV reactivation occurred in 1 (0.1%) patient after initial resolution, whose HBV DNA level spontaneously decreased after DAA therapy. We compared anti-HBs titres at baseline with those at post-DAA therapy in 123 patients without HBsAg. There was no significant difference in anti-HBs levels between the two points (P = .79). In conclusion, HBV reactivation was rare in HBsAg-negative patients treated with DAA therapy. Additionally, hepatitis did not occur in HBV-reactivated patients with a baseline HBV DNA level <2000 IU/mL before DAA therapy.

Serum Wisteria floribunda agglutinin-positive Mac-2-binding protein for patients with chronic hepatitis B and C: a comparative study

We compared Wisteria floribunda agglutinin-positive Mac-2-binding protein (WFA⁺ -M2BP) levels between patients with chronic hepatitis B (n=249) and chronic hepatitis C (n=386) based on the degree of liver fibrosis. We examined WFA⁺ -M2BP levels in patients with F4 (cirrhosis), F3 or more (advanced fibrosis) and F2 or more (significant fibrosis) in the two groups. We further examined the relationship between five fibrosis markers and the degree of fibrosis. The WFA⁺ -M2BP values ranged from 0.25 cut-off index (COI) to 12.9 COI in patients with hepatitis B and 0.34-20.0 COI in patients with hepatitis C (P<.0001). The median WFA⁺ -M2BP values in F4 in the two groups were 2.83 COI in patients with hepatitis B and 5.03 COI in patients with hepatitis C (P=.0046). The median WFA⁺ -M2BP values in F3 or more in the two groups were 1.79 COI in patients with hepatitis B and 3.79 COI in patients with hepatitis C (P<.0001). The median WFA⁺ -M2BP values in F2 or more in the two groups were 1.49 COI in the hepatitis B cohort and 3.19 COI in the hepatitis C group (P<.0001). Among five liver fibrosis markers, WFA⁺ -M2BP had the highest correlation coefficient (r_s =.629) in terms of correlation with the degree of fibrosis in the patients with hepatitis C and had the second highest r_s value (.415) in the hepatitis B group. Although WFA⁺ -M2BP could be a useful indicator of liver fibrosis, WFA⁺ -M2BP levels in the two groups significantly differed even in the same degree of fibrosis. Individual cut-off values in each aetiology for the degree of fibrosis should be determined.

A rare variant in CYP27A1 and its association with atopic dermatitis with high serum total IgE

This study investigated rare variants associated with atopic dermatitis. We performed exome analyses on 37 patients who were diagnosed with atopic dermatitis by board-certified dermatologists and had total serum IgE levels greater than 1000 IU/ml. The exome analysis identified seven variants with <1% allele frequency in Asian (ASN) population of 1000 Genomes Project phase 1 data and >5% allele frequency in the atopic dermatitis exome samples. We then conducted a replication study using 469 atopic dermatitis patients with total serum IgE ≥1000 IU/ml and 935 Japanese controls to assess the presence of these 7 candidate variants. The replication study confirmed that CYP27A1 rs199691576 (A/G) was associated with atopic dermatitis with high serum IgE levels (P = 0.012, odds ratio = 2.1). CYP27A1 is involved in the metabolism of vitamin D3, which plays important roles in modulating immune function. Previous studies have reported polymorphisms in vitamin D pathway genes that are associated with allergy-related phenotypes. Our data confirm the importance of genes regulating the vitamin D pathway in the development of atopic dermatitis.

Is greater than 145{degrees} of deep knee flexion under weight-bearing conditions safe after total knee arthroplasty?: a fluoroscopic analysis of Japanese-style deep knee flexion

We investigated the characteristics of patients who achieved Japanese-style deep flexion (seiza-sitting) after total knee replacement (TKR) and measured three-dimensional positioning and the contact positions of the femoral and tibial components. Seiza-sitting was achieved after surgery by 23 patients (29 knees) of a series of 463 TKRs in 341 patients. Pre-operatively most of these patients were capable of seiza-sitting, had a lower body mass index and a favourable attitude towards the Japanese lifestyle (27 of 29 knees). According to two-/three-dimensional image registration analysis in the seiza-sitting position, flexion, varus and internal rotation angles of the tibial component relative to the femoral component had means of 148° (SD 8.0), 1.9° (SD 3.2) and 13.4° (SD 5.9), respectively. Femoral surface contact positions tended to be close to the posterior edge of the tibial polyethylene insert, particularly in the lateral compartment, but only 8.3% (two of 24) of knees showed femoral subluxation over the posterior edge. The mean contact positions of the femoral cam on the tibial post were located 7.8 mm (sd 1.5) proximal to the lowest point of the polyethylene surface and 5.5 mm (SD 0.9) medial to the centre of the post, indicating that the post-cam contact position translated medially during seiza-sitting, but not proximally. Collectively, the seiza-sitting position seems safe against component dislocation, but the risks of posterior edge loading and breakage of the tibial polyethylene post remain.

Characteristics and enhanced antioxidant activity of egg white protein selenized by dry-heating in the presence of selenite

This study reports a new method for the selenization of food proteins. Egg white protein (EWP) was selenized by dry-heating in the presence of selenite, and the physiochemical and functional properties of the selenized EWP were investigated. Selenization was accelerated with a decrease in pH from 7.0 to 3.0, an increase in heating time from 1 to 5 days, and an increase in incubation temperatures from 25 to 80 °C. The electrophoretic mobility of EWP increased with an increase in the level of selenization. Heat-induced polymerization of EWP was promoted by dry-heating in the presence of selenite. The selenite group was acid-stable and base-labile, which suggests that it was bound to the hydroxyl group of an amino acid and formed an -O-SeHO2 linkage. (77)Se NMR spectral data also suggested that the selenite bond (-O-SeHO2) was bound to EWP. The digestibility of EWP was improved by selenization. The antioxidant activities of EWP, including ABTS(+) free radical scavenging capacity, hydroxyl radical scavenging capacity, reducing power, and the Fe(2+) chelating capacity, were remarkably enhanced by selenization. This finding is the first to describe that EWP can be selenized by dry-heating in the presence of selenite and that the antioxidant activities of EWP are markedly enhanced by selenization. This points to a potentially new method for generating antioxidant food protein and a new method for preparing organic Se.

Anti-interferon-α neutralizing antibody is associated with nonresponse to pegylated interferon-α plus ribavirin in chronic hepatitis C

Pegylated interferon-α (PEG-IFN-α) plus ribavirin (RBV) treatment fails to achieve a sustained virological response (SVR) in approximately 20-50% of patients with chronic hepatitis C virus (HCV) infection. We assessed the contribution of an anti-IFN-α neutralizing antibody (NAb) on the nonresponse to treatment. NAbs were detected using an antiviral assay that assessed the neutralizing effects of serum samples against IFN. Serum samples were obtained at the end of the treatment and evaluated for the presence of NAbs using recombinant IFN-α as a standard. We studied 129 PEG-IFN-α/RBV-treated patients. In the 82 end-of-treatment responders, no NAbs were detected. Of the 47 patients who did not respond, seven (15%) were positive for NAbs. We also examined an additional 83 patients who had not responded to PEG-IFN-α treatment, and detected 12 with NAbs. Patients with good IFN-responsive characteristics, including HCV genotype 2/3 and major allele homozygotes for interleukin-28B, were included in the 19 patients with NAbs. No NAbs interfered with the antiviral activity of natural human IFN-β (nIFN-β) and re-treatement of patients with NAbs with nIFN-β/RBV achieved SVR. Our analyses revealed that the emergence of anti-IFN-α NAbs was a candidate causal factor of PEG-IFN-α-treatment failure. Therefore, these antibodies should be assayed in patients who do not respond to PEG-IFN-α therapy, and if detected, other effective treatments, i.e., medications that are not neutralized by anti-IFN-α NAbs, should be considered.

A multi-level capacitor-less memory cell fabricated on a nano-scale strained silicon-on-insulator

A multi-level capacitor-less memory cell was fabricated with a fully depleted n-metal-oxide-semiconductor field-effect transistor on a nano-scale strained silicon channel on insulator (FD sSOI n-MOSFET). The 0.73% biaxial tensile strain in the silicon channel of the FD sSOI n-MOSFET enhanced the effective electron mobility to ∼ 1.7 times that with an unstrained silicon channel. This thereby enables both front- and back-gate cell operations, demonstrating eight-level volatile memory-cell operation with a 1 ms retention time and 12 µA memory margin. This is a step toward achieving a terabit volatile memory cell.

Imaging mass spectrometry-based histopathologic examination of atherosclerotic lesions

AIMS

Imaging mass spectrometry (IMS) enables the visualization of individual molecules present on tissue sections. We attempted to identify and visualize specific markers for aortic atherosclerotic lesions.

METHODS AND RESULTS

Atherosclerotic lesions were obtained from aortic roots of apolipoprotein E (ApoE)-deficient mice at 60 weeks of age and from femoral arteries of humans with peripheral artery occlusive disease. IMS was performed with a matrix-assisted laser desorption/ionization mass spectrometry time-of-flight (TOF)/TOF-type instrument. The molecular ions at m/z 671.6 and 673.6 were found to be specific molecules in the mouse and human lipid-rich regions. These molecules were assigned as cholesterol linoleate (CE 18:2) and cholesterol oleate (CE 18:1). In the case of the human samples, triacylglycerol was also localized in the lipid-rich regions. The distributions of the molecular ions at m/z 804.5 and 832.5 were the same as the distribution of both the mouse and the human SMCs. These molecules were assigned as phosphatidylcholine (PC) (diacyl 16:0/20:4) and PC (diacyl 18:0/20:4). The molecular ion at m/z 566.9 was localized in the mouse calcified regions, and the molecular ions at m/z 539.0 were localized in the human calcified regions.

CONCLUSIONS

The IMS-based histopathologic examination (IbHE) revealed the characteristic peaks of lipid-rich regions, SMCs, and calcified regions in the atherosclerotic lesions. In addition, IbHE revealed the characteristic distribution of lipids in human atherosclerotic lesions. These data indicate that an IMS-based pathologic approach is of considerable value as a new histopathologic examination.