Impact of Climate on Soil Organic Matter Composition in Soils of Tropical Volcanic Regions Revealed by EGA-MS and Py-GC/MS.

Soil organic matter (SOM) crucially influences the global carbon cycle, yet its molecular composition and determinants are understudied, especially for tropical volcanic regions. We investigated how SOM compounds change in response to climate, vegetation, soil horizon, and soil properties and the relationship between SOM composition and microbial decomposability in Tanzanian and Indonesian volcanic regions. We collected topsoil (0-15 cm) and subsoil (20-40 cm) horizons (n = 22; pH: 4.6-7.6; SOC: 10-152 g kg-1) with undisturbed vegetation and wide mean annual temperature and moisture ranges (14-26 °C; 800-3300 mm) across four elevational transects (340-2210 m asl.). Evolved gas analysis-mass spectrometry (EGA-MS) documented a simultaneous release of SOM compounds and clay mineral dehydroxylation. Subsequently applying double-shot pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) at 200 and 550 °C, we detailed the molecular composition of topsoil and subsoil SOM. A minor portion (2.7 ± 1.9%) of compounds desorbed at 200 °C, limiting its efficacy for investigating overall SOM characteristics. Pyrolyzed SOM closely aligns with the intermediate decomposable SOM pool, with most pyrolysates (550 °C) originating from this pool. Pyrolysates composition suggests tropical SOM is mainly microbial-derived and subsoil contains more degraded compounds. Higher litter inputs and attenuated SOM decomposition due to cooler temperatures and lower soil pH (<5.5) produce less-degraded SOM at higher elevations. Redundancy analyses revealed the crucial role of active Al/Fe (oxalate-extractable Al/Fe), abundant in low-temperature/high-moisture conditions, in stabilizing these less-degraded components. Our findings provide new insights into SOM molecular composition and its determinants, critical for understanding the carbon cycle in tropical ecosystems.

Taxonomic difference in marine bloom-forming phytoplanktonic species affects the dynamics of both bloom-responding prokaryotes and prokaryotic viruses.

The production of dissolved organic matter during phytoplankton blooms and consumption by heterotrophic prokaryotes promote marine carbon biogeochemical cycling. Although prokaryotic viruses presumably affect this process, their dynamics during blooms are not fully understood. Here, we investigated the effects of taxonomic difference in bloom-forming phytoplankton on prokaryotes and their viruses. We analyzed the dynamics of coastal prokaryotic communities and viruses under the addition of dissolved intracellular fractions from taxonomically distinct phytoplankton, the diatom Chaetoceros sp. (CIF) and the raphidophycean alga Heterosigma akashiwo (HIF), using microcosm experiments. Ribosomal RNA gene amplicon and viral metagenomic analyses revealed that particular prokaryotes and prokaryotic viruses specifically increased in either CIF or HIF, indicating that taxonomic difference in bloom-forming phytoplankton promotes distinct dynamics of not only the prokaryotic community but also prokaryotic viruses. Furthermore, combining our microcosm experiments with publicly available environmental data mining, we identified both known and novel possible host-virus pairs. In particular, the growth of prokaryotes associating with phytoplanktonic organic matter, such as Bacteroidetes (Polaribacter and NS9 marine group), Vibrio spp., and Rhodobacteriales (Nereida and Planktomarina), was accompanied by an increase in viruses predicted to infect Bacteroidetes, Vibrio, and Rhodobacteriales, respectively. Collectively, our findings suggest that changes in bloom-forming species can be followed by an increase in a specific group of prokaryotes and their viruses and that elucidating these tripartite relationships among specific phytoplankton, prokaryotes, and prokaryotic viruses improves our understanding of coastal biogeochemical cycling in blooms.IMPORTANCEThe primary production during marine phytoplankton bloom and the consumption of the produced organic matter by heterotrophic prokaryotes significantly contribute to coastal biogeochemical cycles. While the activities of those heterotrophic prokaryotes are presumably affected by viral infection, the dynamics of their viruses during blooms are not fully understood. In this study, we experimentally demonstrated that intracellular fractions of taxonomically distinct bloom-forming phytoplankton species, the diatom Chaetoceros sp. and the raphidophycean alga Heterosigma akashiwo, promoted the growth of taxonomically different prokaryotes and prokaryotic viruses. Based on their dynamics and predicted hosts of those viruses, we succeeded in detecting already-known and novel possible host-virus pairs associating with either phytoplankton species. Altogether, we propose that the succession of bloom-forming phytoplankton would change the composition of the abundant prokaryotes, resulting in an increase in their viruses. These changes in viral composition, depending on bloom-forming species, would alter the dynamics and metabolism of prokaryotes, affecting biogeochemical cycling in blooms.

Polycystic ovary syndrome in a patient with type B insulin resistance syndrome can improve with glucocorticoid treatment: a case report and literature review.

Polycystic ovary syndrome (PCOS) frequently exhibits hyperinsulinemia due to insulin resistance, but there are many unknown aspects of this disease. This report presents the case of a 31-year-old woman with PCOS and type B insulin resistance syndrome (TBIRS). The patient had repeated hyperglycemia and hypoglycemia, and prominent hyperinsulinemia. The insulin receptor antibody was positive, leading to a diagnosis of TBIRS. She also had amenorrhea during the previous 3 months, high blood testosterone levels, and enlarged polycystic ovaries, leading to a diagnosis of PCOS at the same time. The patient was treated with glucocorticoid for TBIRS. The insulin receptor antibody eliminated at 8 weeks after initiation of glucocorticoid treatment, and the blood glucose levels and hyperinsulinemia improved at 9 weeks. Then, the enlargement of both ovaries diminished at 32 weeks, and the menstruation had normalized since 36 weeks. The blood testosterone level normalized at 41 weeks. To the best of our knowledge, this is the first report to demonstrate that enlarged polycystic ovaries and a menstrual disorder in TBIRS improved after glucocorticoid treatment. It is possible that elimination of insulin receptor antibodies by glucocorticoid treatment attenuated insulin resistance and subsequently improved PCOS in TBIRS.

Do multiple types of confirmatory tests improve performance in predicting subtypes of primary aldosteronism?

OBJECTIVE: The clinical practice guideline for primary aldosteronism (PA) places a high value on confirmatory tests to sparing patients with false-positive results in case detection from undergoing adrenal venous sampling (AVS). However, it is unclear whether multiple types of confirmatory tests are more useful than a single type. To evaluate whether the machine-learned combination of two confirmatory tests is more useful in predicting subtypes of PA than each test alone. DESIGN: A retrospective cross-sectional study in referral centres. PATIENTS: This study included 615 patients with PA randomly assigned to the training and test data sets. The participants underwent saline infusion test (SIT) and captopril challenge test (CCT) and were subtyped by AVS (unilateral, n = 99; bilateral, n = 516). MEASUREMENTS: The area under the curve (AUC) and clinical usefulness using decision curve analysis for the subtype prediction in the test data set. RESULTS: The AUCs for the combination of SIT and CCT, SIT alone and CCT alone were 0.850, 0.813 and 0.786, respectively, with no significant differences between them. The AUC for the baseline clinical characteristics alone was 0.872, whereas the AUCs for these combined with SIT, combined with CCT and combined with both SIT and CCT were 0.868, 0.854 and 0.855, respectively, with no significant improvement in AUC. The additional clinical usefulness of the second confirmatory test was unremarkable on decision curve analysis. CONCLUSIONS: Our data suggest that patients with positive case detection undergo one confirmatory test to determine the indication for AVS.

Right adrenal vein identification using unenhanced magnetic resonance imaging.

Purpose: Unenhanced magnetic resonance imaging (MRI) is known to be useful in characterizing adrenal adenomas through the implementation of in-phase (IPI) and opposed-phase imaging (OPI) based on chemical shift artifacts. However, whether unenhanced MRI can contribute to the identification of right adrenal vein (RAV) remains unclear. The aim of this study was to evaluate the feasibility of unenhanced MRI for the identification of RAV. Material and methods: This retrospective study reviewed 30 patients (16 men; median age 60 years; range 34-76 years) who underwent MRI and subsequent adrenal venous sampling (AVS). Chemical shift MRI was acquired using echo times of 2.3 ms (OPI) and 4.6 ms (IPI) with a slice thickness of 3 mm and a gap of 1 mm. T2-weighted imaging (T2WI) was also performed. Identification of RAVs was performed by 2 independent radiologists. Inter-observer agreement on a 3-point rating scale was evaluated using κ statistics. The identification rate of RAVs was compared between OPI, IPI, and T2WI using McNemar's test. Results: Good inter-observer agreement was found for the OPI (κ = 0.744), whereas fair agreement was obtained for both other sequences (IPI: κ = 0.375; T2WI: 0.348). For both raters, the identification rate of RAVs was higher with OPI (36/60; 60.0%) than with other sequences (IPI: 16/60, 26.7%; T2WI: 9/60, 15.0%; p < 0.05, each). Conclusions: OPI may play a screening role in the identification of RAVs preceding AVS, which could reduce the required radiation exposure and doses of contrast agent.

Higher Serum Soluble TREM2 as a Potential Indicative Biomarker for Cognitive Impairment in Inadequately Controlled Type 2 Diabetes Without Obesity: The DOR-KyotoJ-1.

Objective: Type 2 diabetes is a risk factor for dementia. We investigated whether serum levels of soluble triggering receptor expressed on myeloid cell 2 (sTREM2), a soluble form of the cell surface receptor TREM2, were predictive of cognitive impairment in type 2 diabetes without obesity. Methods: A total of 166 Japanese patients with type 2 diabetes without obesity were followed-up for 2 years. We measured clinical parameters, assessed cognitive function using the mini-mental state examination (MMSE), quantified and divided serum sTREM2 levels into quartiles, and examined the longitudinal associations. Results: During the follow-up, HbA1c levels were elevated in 98 patients and decreased in 68 patients. In the HbA1c-elevated group, higher sTREM2 levels at baseline showed a significant association with a greater tendency for reduction in MMSE scores (P for trend = 0.015), whereas they were not significantly associated with other examined parameters. In the HbA1c-decreased group, there was no significant association between sTREM2 levels at baseline and changes in MMSE scores, but higher sTREM2 levels at baseline were significantly associated with a greater tendency for reduction in waist circumference (P for trend = 0.027), homeostasis model assessment of insulin resistance (P for trend = 0.039), and sTREM2 levels (P for trend = 0.023). Conclusions: Glycemic control is suggested to be important in preventing cognitive impairment in patients with type 2 diabetes without obesity. Higher serum sTREM2 levels would be a predictive marker for cognitive impairment in inadequately controlled type 2 diabetes without obesity.

Machine learning-based models for predicting clinical outcomes after surgery in unilateral primary aldosteronism.

Unilateral subtype of primary aldosteronism (PA) is a common surgically curable form of endocrine hypertension. However, more than half of the patients with PA who undergo unilateral adrenalectomy suffer from persistent hypertension, which may discourage those with PA from undergoing adrenalectomy even when appropriate. The aim of this retrospective cross-sectional study was to develop machine learning-based models for predicting postoperative hypertensive remission using preoperative predictors that are readily available in routine clinical practice. A total of 107 patients with PA who achieved complete biochemical success after adrenalectomy were included and randomly assigned to the training and test datasets. Predictive models of complete clinical success were developed using supervised machine learning algorithms. Of 107 patients, 40 achieved complete clinical success after adrenalectomy in both datasets. Six clinical features associated with complete clinical success (duration of hypertension, defined daily dose (DDD) of antihypertensive medication, plasma aldosterone concentration (PAC), sex, body mass index (BMI), and age) were selected based on predictive performance in the machine learning-based model. The predictive accuracy and area under the curve (AUC) for the developed model in the test dataset were 77.3% and 0.884 (95% confidence interval: 0.737-1.000), respectively. In an independent external cohort, the performance of the predictive model was found to be comparable with an accuracy of 80.4% and AUC of 0.867 (95% confidence interval: 0.763-0.971). The duration of hypertension, DDD of antihypertensive medication, PAC, and BMI were non-linearly related to the prediction of complete clinical success. The developed predictive model may be useful in assessing the benefit of unilateral adrenalectomy and in selecting surgical treatment and antihypertensive medication for patients with PA in clinical practice.

Factors controlling sizes and stabilities of subsoil organic carbon pools in tropical volcanic soils.

Soil organic carbon (SOC) in the subsoil may not be so resistant to decomposition as previously assumed, while the mechanisms controlling C dynamics in subsoils are not yet known. This study aimed to (1) identify the factors that control SOC pools in subsoil and (2) compare the differences in SOC pools and controlling factors between the subsoil and topsoil. Subsoils (20-40 cm) were sampled along elevational gradients from two volcanic regions with less-disturbed vegetation each from Tanzania (11 sites) and Indonesia (12 sites). The sizes and mean residence times of labile, intermediate, and stable SOC pools were estimated by fractionation and model fitting to CO2 release during long-term incubation. The controlling factors of each SOC pool were determined by accompanying partial correlation and path analyses. In subsoil, the intermediate SOC pool predominantly controlled the SOC stability within decades. Climatic, geochemical, and biotic factors controlled different SOC pools. Temperature negatively affected the sizes of all three pools. The nanocrystalline minerals contents predominantly and positively controlled the sizes of intermediate and stable SOC pools, and the mean residence time of intermediate SOC pool. Biotic and climatic factors (i.e., microbial biomass, available N for microbes, and excess precipitation) controlled the labile SOC pool. Compared with topsoil, stabilized organic matters were more in the intermediate rather than in the stable SOC pool, and the temperature had a more significant effect on the stable SOC pool in subsoil than in topsoil. Available N for microbes partially controlled the labile and intermediate SOC pools in subsoil (more limited available N for microbes), but not in topsoil. Thus, subsoil SOC would be more sensitive to climate change than topsoil SOC. This study helped to understand the SOC stabilization mechanism and emphasized the high climate- and mineral-dependence of SOC in subsoil of tropical volcanic regions.

Soil organic carbon pools controlled by climate and geochemistry in tropical volcanic regions.

Understanding the factors that control the storage of soil organic carbon (SOC) is an urgent priority for mitigating global climate problems. The objective of this study was to determine the factors controlling SOC pools with differing stabilities. Surface soil samples were collected along an elevation gradient from four volcanic regions of Tanzania (two regions) and Indonesia (two regions) under largely-undisturbed vegetation (24 sites in total). A three-pool kinetic model was fitted to accumulative CO2 release curve produced over 343-day incubation to determine the sizes of the labile and intermediate SOC pools (CL and CI, respectively) and their mean residence times (1/KL and 1/KI, respectively), where the size of the stable SOC pool (CS) was measured as non-hydrolyzable carbon. Correlation and path analyses were performed using the results of soil fractionation and model fitting with climatic and geochemical properties. The intermediate pool comprised 50% of total SOC, was responsible for 58% of total accumulative CO2 release, and controlled total SOC stability. The content of nanocrystalline minerals (Alo + 1/2Feo: 5.5-110 g kg-1) was strongly correlated with CI and CS, suggesting that organo-mineral complexes is the essential factor that controls CI and CS rather than soil texture or pH. Temperature (12-26 °C) was weakly correlated with CI, CS, and strongly with CL, which was closely related to microbial biomass carbon. The low temperature at the high elevation sites retards the decomposition of the whole SOC. The significant correlations of excess precipitation with 1/KL and 1/KI represent the effect of moisture on the potential stabilities of the labile and intermediate SOC pools. Climatic factors primarily affect relatively labile SOC pools, whereas geochemical factors influence more stable pools and control total SOC. The findings have important implications for understanding the SOC stabilization mechanisms, which is an essential process of the carbon cycle, in tropical volcanic soils.

Wetland environmental bioreactor system contributes to the decomposition of cellulose.

Recently, numerous species of aquatic invertebrates inhabiting wetlands have been shown to possess endogenous cellulase, following the discovery that termites have cellulase genes encoded in their own genome rather than relying on symbiotic bacteria for decomposing cellulose. Wetlands have been empirically shown to play an important role in the decomposition of land-originating hard-to-degrade polysaccharides such as cellulose. However, the mechanism that connects the cellulase producer and the wetlands remains unknown, which makes it very difficult to evaluate the ecological function of wetlands. Here we found that a macrobenthic bivalve, Corbicula japonica, secretes its cellulase to the wetland sediment. Secreted cellulases are immobilized in the components of the sediment. Moreover, adding cellulose or glucose to C. japonica could trigger its cellulase secretion level. These findings suggest a novel wetland cellulose decomposition mechanism. The decomposition ability of wetlands was previously ascribed only to microbes and/or invertebrates that contain cellulases. Our findings suggest that benthic animals supply wetlands with their enzymes as decomposition agents, while wetland sediments serve as immobilization scaffolds for the enzymes. This system, which was named by us an "environmental bioreactor system," could provide a key function in wetlands.

Dehydroepiandrosterone-enhanced dual specificity protein phosphatase (DDSP) prevents diet-induced and genetic obesity.

Dehydroepiandrosterone (DHEA) exerts a wide variety of therapeutic effects against medical disorders, such as diabetes and obesity. However, the molecular basis of DHEA action remains to be clarified. Previously, we reported that DHEA-enhanced dual specificity protein phosphatase, designated DDSP, is one of the target molecules of DHEA. To examine the role of DDSP in DHEA signaling, we generated mice that carry a DDSP transgene in which expression is driven by the CAG promoter (DDSP-Tg). DDSP-Tg mice weighed significantly less than wild-type (WT) control mice when a high fat diet was supplied (p < 0.01). No difference in food-intake or locomotor activity was found between DDSP-Tg and WT mice. Oxygen consumption of DDSP-Tg mice was higher than that of WT mice (p < 0.01), which suggested an increase in basal metabolism in DDSP-Tg mice. To further investigate the role of DDSP in genetic obese mice, DDSP-Tg mice with a db/db background were generated (DDSP-Tg db/db). We observed cancellation of obesity by the db/db mutation and development of a cachexic phenotype in DDSP-Tg db/db mice. In conclusion, our study shows that expression of DDSP leads to prevention of diet-induced and genetic (db/db) obesity. Anti-obese effects of DHEA might be mediated through DDSP, which might be a therapeutic target for intervention of obesity.

Detection of anaerobic carbon monoxide-oxidizing thermophiles in hydrothermal environments.

Carboxydotrophic anaerobic thermophiles have been isolated from various hydrothermal environments and are considered to be important carbon monoxide (CO) scavengers or primary producers. However, the ecological factors that influence the distribution, abundance and CO-oxidizing activities of these bacteria are poorly understood. A previous study detected the carboxydotrophic bacteria Carboxydothermus spp. in a hot spring sample and found that they constituted up to 10% of the total bacterial cells. In this study, we investigated environmental features, potential microbial CO-oxidation activities and the abundance of Carboxydothermus spp. in various hot springs to determine environmental factors that affect CO oxidizers and to see whether Carboxydothermus spp. are common in these environments. We detected potential microbial CO-oxidation activities in samples that showed relatively high values of total organic carbon, total nitrogen, oxidation-reduction potential and soil-water content. The abundance of Carboxydothermus spp. did not correlate with the presence of potential microbial CO-oxidation activities; however, Carboxydothermus spp. were detected in a wide range of environments, suggesting that these bacteria are widely distributed in spite of the relatively low population size. This study implies that thermophilic CO oxidizers occur in a wide range of environments and oxidize CO in somewhat oxidative environments rich in organic matter.

Association of symptoms of gastroesophageal reflux with metabolic syndrome parameters in patients with endocrine disease.

Background. Metabolic syndrome (MetS) and obesity are known risk factors for gastroesophageal reflux disease (GERD), which is often found in patients with endocrine disorders, such as thyroid dysfunction and hypopituitarism. To clarify the relationship of endocrine disease with GERD, we investigated the symptoms of GERD in patients with various endocrine diseases. Methods. Patients with various endocrine disorders who visited Kyushu University Hospital were included. GERD symptoms were examined using a self-administered questionnaire, the frequency scale for the symptoms of GERD (FSSG). Metabolic parameters, including body-mass index (BMI), waist circumference, blood pressure, hemoglobin A1c, total cholesterol, high-density lipoprotein cholesterol (HDL-C), and triglycerides, and values of endocrine function, including thyroid stimulating hormone, free thyroxin, cortisol, and insulin-like growth factor-1, were assessed. Results. A total of 111 consecutive patients were recruited for the study. Among these, 18 (16.2%) patients were considered to have GERD. Among the parameters, BMI (P = 0.03) and triglycerides (P = 0.001) showed a positive association and HDL-C (P = 0.0007) showed an inverse association with the FSSG score. However, none of the endocrine values were associated with the FSSG score. Conclusion. Symptoms of GERD in patients with endocrine disorders might be attributed to MetS as comorbidity.

Sex hormone and neuroendocrine aspects of the metabolic syndrome.

We discuss the recent advances in the knowledge that the sex steroids testosterone (T), estradiol and dehydroepiandrosterone sulphate (DHEA-S) are involved in the development of visceral obesity and of the metabolic syndrome. Cross talk between leptin and the androgen receptor (AR) in the hypothalamus as well as the peripheral conversion of DHEA and T to estrone, estradiol and dihydrotestosterone (DHT) in adipocytes and hepatocytes play important roles in the metabolic syndrome in men. Finally, we discuss the development of new drugs, selective AR modulators, for treating the metabolic syndrome in men.

Adrenal failure caused by a retroperitoneal malignant mesothelioma.

A 62-year-old man presented with clinical signs of acute abdominal pain and adrenal insufficiency. Computerized tomographic scans revealed bilateral adrenal tumors and the left adrenal tumor was surgically resected. The patient was found to have retroperitoneal mesothelioma presenting as bilateral metastatic adrenal tumors, which were well controlled by systemic chemotherapy with CDDP and 5-FU. This case appears to be the first reported case in the literature of adrenal failure due to bilateral adrenal infiltration caused by retroperitoneal malignant mesothelioma.

Adrenopause.

Dehydroepiandrosterone(DHEA) and DHEA-S are steroids that are abundantly produced by the adrenal gland. Plasma concentrations of DHEA and DHEA-S increase during adrenarche but decrease steadily after puberty. Although DHEA and DHEA-S have few intrinsic androgenic actions, they have recently attracted widespread attention due to their beneficial anti-aging effects. We clarified the beneficial effects of DHEA as an anti-aging steroid with regard to its stimulation of the immune system and its anti-diabetes, anti-atherosclerosis, anti-dementia (neurosteroid), anti-obesity and anti-osteoporosis effects. There are two possible biochemical and molecular mechanisms: direct action via the DHEA receptor on the target gene; and indirect action. We identified a high affinity of DHEA binding in human T-lymphocytes by searching for the target genes that are induced in activated T-lymphocytes in the presence of DHEA, determined the gene sequence and named DHEA-induced dual p38-specific phosphatase (DDSP). DDSP transgenic mice have been created to identify the anti-aging effects of DDSP. The conversion of DHEA to estrone by cytochrome P450 aromatase in primary cultured human osteoblasts was clarified. We are currently undertaking an open trial of DHEA replacement therapy.