Comparative and functional analyses of fecal microbiome in Asian elephants.

Asian elephant is large herbivorous animal with elongated hindgut. To explore fecal microbial community composition with various ages, sex and diets, and their role in plant biomass degrading and nutrition conversation. We generated 119 Gb by metagenome sequencing from 10 different individual feces and identified 5.3 million non-redundant genes. The comprehensive analysis established that the Bacteroidetes, Firmicutes and Proteobacteria constituted the most dominant phyla in overall fecal samples. In different individuals, the alpha diversity of the fecal microbiota in female was lower than male, and the alpha diversity of the fecal microbiota in older was higher than younger, and the fecal microbial diversity was the most complex in wild elephant. But the predominant population compositions were similar to each other. Moreover, the newborn infant elephant feces assembled and maintained a diverse but host-specific fecal microbial population. The discovery speculated that Asian elephant maybe have start to building microbial populations before birth. Meanwhile, these results illustrated that host phylogeny, diets, ages and sex are significant factors for fecal microbial community composition. Therefore, we put forward the process of Asian elephant fecal microbial community composition that the dominant populations were built first under the guidance of phylogeny, and then shaped gradually a unique and flexible gut microbial community structure under the influences of diet, age and sex. This study found also that the Bacteroidetes were presumably the main drivers of plant fiber-degradation. A large of secondary metabolite biosynthetic gene clusters, and genes related to enediyne biosynthesis were found and showed that the Asian elephant fecal microbiome harbored a diverse and abundant genetic resource. A picture of antibiotic resistance genes (ARGs) reservoirs of fecal microbiota in Asian elephants was provided. Surprisingly, there was such wide range of ARGs in newborn infant elephant. Further strengthening our speculation that the fetus of Asian elephant has colonized prototypical fecal microbiota before birth. However, it is necessary to point out that the data give a first inside into the gut microbiota of Asian elephants but too few individuals were studied to draw general conclusions for differences among wild and captured elephants, female and male or different ages. Further studies are required. Additionally, the cultured actinomycetes from Asian elephant feces also were investigated, which the feces of Asian elephants could be an important source of actinomycetes.

Effects of carotid baroreceptor stimulation on aortic remodeling in obese rats.

BACKGROUND AND AIM: Our previous study found carotid baroreceptor stimulation (CBS) reduces body weight and white adipose tissue (WAT) weight, restores abnormal secretion of adipocytokines and inflammation factors, decreases systolic blood pressure (SBP) by inhibiting activation of sympathetic nervous system (SNS) and renin-angiotensin system (RAS) in obese rats. In this study, we explore effects of CBS on aortic remodeling in obese rats. METHODS AND RESULTS: Rats were fed high-fat diet (HFD) for 16 weeks to induce obesity and underwent either CBS device implantation and stimulation or sham operation at 8 weeks. BP and body weight were measured weekly. RAS activity of WAT, histological, biochemical and functional profiles of aortas were detected after 16 weeks. CBS effectively decreased BP in obese rats, downregulated mRNA expression of angiotensinogen (AGT) and renin in WAT, concentrations of AGT, renin, angiotensin II (Ang II), protein levels of Ang II receptor 1 (AT1R) and Ang II receptor 2 (AT2R) in WAT were declined. CBS inhibited reactive oxygen species (ROS) generation, inflammatory response and endoplasmic reticulum (ER) stress in aortas of obese rats, restrained vascular wall thickening and vascular smooth muscle cells (VSMCs) phenotypic switching, increased nitric oxide (NO) synthesis, promoted endothelium-dependent vasodilatation by decreasing protein expression of AT1R and leptin receptor (LepR), increasing protein expression of adiponectin receptor 1 (AdipoR1) in aortic VSMCs. CONCLUSION: CBS reduced BP and reversed aortic remodeling in obese rats, the underlying mechanism might be related to the suppressed SNS activity, restored adipocytokine secretion and restrained RAS activity of WAT.

Profiles of liver function abnormalities in elderly patients with Coronavirus Disease 2019.

BACKGROUND: The profiles of liver function abnormalities in COVID-19 patients need to be clarified. METHODS: In this retrospective study, consecutive COVID-19 patients over 60 years old in Renmin Hospital of Wuhan University from January 1 to February 6 were included. Data of demographics, clinical characteristics, comorbidities, laboratory tests, medications and outcomes were collected and analysed. Sequential alterations of serum alanine aminotransferase (ALT) were monitored. RESULTS: A total of 330 patients were included and classified into two groups with normal (n = 234) or elevated ALT (n = 96). There were fewer females (40.6% vs 54.7%, P = .020) and more critical cases (30.2% vs 19.2%, P = .026) in patients with elevated ALT compared with the normal group. Higher levels of bacterial infection indices (eg, white blood cell count, neutrophil count, C-reactive protein and procalcitonin) were observed in the elevated group. Spearman correlation showed that both ALT and AST levels were positively correlated with those indices of bacterial infection. No obvious effects of medications on ALT abnormalities were found. In patients with elevated ALT, most ALT elevations were mild and transient. 59.4% of the patients had ALT concentrations of 41-100 U/L, while only a few patients (5.2%) had high serum ALT concentrations above 300 U/L. ALT elevations occurred at 13 (10-17) days and recovered at 28 (18-35) days from disease onset. For most patients, the elevation of serum ALT levels occurred at 6-20 days after disease onset and reached their peak values within a similar time frame. The recovery of serum ALT levels to normal frequently occurred at 16-20 days or 31-35 days after disease onset. CONCLUSIONS: Liver function abnormalities were observed in 29.1% of elderly people COVID-19 patients, which were slightly and transient in most cases. Liver function abnormalities in COVID-19 may be correlated with bacterial infection.

Night-Time Premature Ventricular Complex Positively Correlates With Cardiac Sympathetic Activity in Patients Undergoing Radiofrequency Catheter Ablation.

BACKGROUND: Patients with premature ventricular complexes (PVCs) usually experience accompanying alterations of the autonomic nerve system. The timing of PVC occurrence is associated with different circadian rhythms, which may be related to the autonomic nerve imbalance. The relationship between night-time PVC and cardiac autonomic nervous activity is still obscure. Our study aimed to investigate the relationship between the number of night-time PVCs and cardiac autonomic nervous activity. METHOD: We enrolled 72 patients with frequent PVCs and 27 without PVCs. The patients with PVCs were divided into two groups based on the number of night-time PVCs (i.e., PVCs occurring between 10 pm and 6 am/24-hr total PVCs; group 1: n=34, <30%; group 2: n=38, >30%). At baseline, 12-lead electrocardiogram and 24-hour Holter recording were performed. When the number of PVCs declined significantly after radiofrequency catheter ablation, Holter monitoring was performed again. Heart rate (HR) variability, mean 24-hour HR, mean daytime HR, and mean night-time HR were analysed. RESULTS: With a greater number of night-time PVCs, group 2 had a lower standard deviation of all NN intervals (SDNN; 116.5±38.3 vs 135.3±37.8 ms; p=0.035) and increased mean 24-hour HR (77.3±9.2 vs 73.4±7.5 beats per min; p=0.05) than group 1. The SDNN was negatively correlated with the number of night-time PVCs and mean night-time HR (r= -3.04 and r= -0.504, respectively; p=0.009 and p=<0.001, respectively), and night-time PVC proportion was positively correlated with the ratio of low-frequency power (LF)/high-frequency power (HF; r=0.319 [p=0.013]). Multivariate linear regression analysis showed that the number of night-time PVCs was an independent predictor of decreased SDNN (ß= -0.446, p=0.030) and increased LF/HF ratio (ß=0.027, p=0.038). After PVCs disappeared, SDNN increased significantly and the frequency domain of the square root of the mean of the sum of the squares of differences between adjacent NN intervals, NN50 count divided by the total number of all NN intervals, the time domain of natural logarithm of HF, natural logarithm of LF, and mean 24-hour HR were significantly decreased in the two PVC groups. CONCLUSIONS: An increased number of night-time PVCs was accompanied by enhanced cardiac sympathetic activity. After PVCs diminished, both cardiac parasympathetic and sympathetic nervous activity declined.

Carotid baroreceptor stimulation in obese rats affects white and brown adipose tissues differently in metabolic protection.

The sympathetic nervous system (SNS) regulates the functions of white adipose tissue (WAT) and brown adipose tissue (BAT) tightly. Carotid baroreceptor stimulation (CBS) efficiently inhibits SNS activation. We hypothesized that CBS would protect against obesity. We administered CBS to obese rats and measured sympathetic and AMP-activated protein kinase (AMPK)/ PPAR pathway responses as well as changes in perirenal WAT (PWAT), epididymal WAT (EWAT), and interscapular BAT (IBAT). CBS alleviated obesity-related metabolic changes, improving insulin resistance; reducing adipocyte hypertrophy, body weight, and adipose tissue weights; and decreasing norepinephrine but increasing acetylcholine in plasma, PWAT, EWAT, and IBAT. CBS also downregulated fatty acid translocase (CD36), fatty acid transport protein (FATP), phosphorylated and total hormone sensitive lipase, phosphorylated and total protein kinase A, and PPARγ in obese rats. Simultaneously, CBS upregulated phosphorylated adipose triglyceride lipase, phosphorylated and total AMPK, and PPARα in PWAT, EWAT, and IBAT. However, BAT and WAT responses differed; although many responses were more sensitive in IBAT, responses of CD36, FATP, and PPARγ were more sensitive in PWAT and EWAT. Overall, CBS decreased chronically activated SNS and ameliorated obesity-related metabolic disorders by regulating the AMPK/PPARα/γ pathway.

Carotid baroreceptor stimulation suppresses ventricular fibrillation in canines with chronic heart failure.

Carotid baroreceptor stimulation (CBS) has been shown to improve cardiac dysfunction and pathological structure remodelling. This study aimed to investigate the effects of CBS on the ventricular electrophysiological properties in canines with chronic heart failure (CHF). Thirty-eight beagles were randomized into control (CON), CHF, low-level CBS (LL-CBS), and moderate-level CBS (ML-CBS) groups. The CHF model was established with 6 weeks of rapid right ventricular pacing (RVP), and concomitant LL-CBS and ML-CBS were applied in the LL-CBS and ML-CBS groups, respectively. After 6 weeks of RVP, ventricular electrophysiological parameters and left stellate ganglion (LSG) neural activity and function were measured. Autonomic neural remodelling in the LSG and left ventricle (LV) and ionic remodelling in the LV were detected. Compared with the CHF group, both LL-CBS and ML-CBS decreased spatial dispersion of action potential duration (APD), suppressed APD alternans, reduced ventricular fibrillation (VF) inducibility, and inhibited enhanced LSG neural discharge and function. Only ML-CBS significantly inhibited ventricular repolarization prolongation and increased the VF threshold. Moreover, ML-CBS inhibited the increase in growth-associated protein-43 and tyrosine hydroxylase-positive nerve fibre densities in LV, increased acetylcholinesterase protein expression in LSG, and decreased nerve growth factor protein expression in LSG and LV. Chronic RVP resulted in a remarkable reduction in protein expression encoding both potassium and L-type calcium currents; these changes were partly amended by ML-CBS and LL-CBS. In conclusion, CBS suppresses VF in CHF canines, potentially by modulating autonomic nerve and ion channels. In addition, the effects of ML-CBS on ventricular electrophysiological properties, autonomic remodelling, and ionic remodelling were superior to those of LL-CBS.

Effect of acupuncture at Neiguan point combined with amiodarone therapy on early recurrence after pulmonary vein electrical isolation in patients with persistent atrial fibrillation.

OBJECTIVE: Early atrial fibrillation (AF) recurrences are common and have been shown to predict AF recurrences late after AF ablation during follow-up. Neiguan point acupuncture has been recognized to be therapeutic in treating AF in clinical practice. METHODS AND RESULTS: Eighty-five patients were enrolled in succession due to persistent AF. All patients were randomized divided into control group and acupuncture group. In the control group (n = 45), amiodarone was orally taken from the first day after pulmonary vein isolation (PVI). In the acupuncture group (n = 40), patients were treated with Neiguan point acupuncture for 7 days and amiodarone was prescribed as same as the control group after PVI. The levels of inflammatory factors were analyzed before operation, 1 week after the operation and 3 months later. After 3 months, the acupuncture group had a lower rate of early recurrences than the control group (5/40 [12.5%] vs 15/45 [33.3%], P = 0.039). The inflammatory factors level in the two groups were significantly increased after ablation. However, compared with the control group, the levels of TNF-α, IL-6, CRP, TGF-ß1, MMP2 in the acupuncture group significantly lower (P < 0.05). In a multivariate analysis, acupuncture was an independent factor associated with a lower rate of early recurrences during the blanking period (odds ratio, 0.17; 95% confidence interval, 0.05-0.63; P = 0.008). CONCLUSION: Neiguan point acupuncture combined with amiodarone is superior to amiodarone alone in reducing early recurrences of patients with persistent AF after PVI. The efficacy of Neiguan acupuncture therapy on the early recurrence is associated with the decreased inflammation factors.

Cardioprotective role of growth/differentiation factor 1 in post-infarction left ventricular remodelling and dysfunction.

Growth/differentiation factor 1 (GDF1) is a secreted glycoprotein of the transforming growth factor-ß (TGF-ß) superfamily that mediates cell differentiation events during embryonic development. GDF1 is expressed in several tissues, including the heart. However, the functional role of GDF1 in myocardial infarction (MI)-induced cardiac remodelling and dysfunction is not known. Here, we performed gain-of-function and loss-of-function studies using cardiac-specific GDF1 transgenic (TG) and knockout (KO) mice to determine the role of GDF1 in the pathogenesis of functional and architectural cardiac remodelling after MI, which was induced by surgical left anterior descending coronary artery ligation. Our results demonstrate that overexpression of GDF1 in the heart causes a significant decrease in MI-derived mortality post-MI and leads to attenuated infarct size expansion, left ventricular (LV) dilatation, and cardiac dysfunction at 1 week and 4 weeks after MI injury. Compared with control animals, cardiomyocyte apoptosis, inflammation, hypertrophy, and interstitial fibrosis were all remarkably reduced in the GDF1-TG mice following MI. In contrast, GDF1 deficiency greatly exacerbated the pathological cardiac remodelling response after infarction. Further analysis of the in vitro and in vivo signalling events indicated that the beneficial role of GDF1 in MI-induced cardiac dysfunction and LV remodelling was associated with the inhibition of non-canonical (MEK-ERK1/2) and canonical (Smad) signalling cascades. Overall, our data reveal that GDF1 in the heart is a novel mediator that protects against the development of post-infarction cardiac remodelling via negative regulation of the MEK-ERK1/2 and Smad signalling pathways. Thus, GDF1 may serve as a valuable therapeutic target for the treatment of MI.

Dickkopf-3 protects against cardiac dysfunction and ventricular remodelling following myocardial infarction.

Dickkopf-3 (DKK3) is a secreted glycoprotein of the Dickkopf family (DKK1-4) that modulates Wnt signalling. DKK3 has been reported to regulate cell development, proliferation, apoptosis, and immune response. However, the functional role of DKK3 in cardiac remodelling after myocardial infarction (MI) has not yet been elucidated. This study aimed to explore the functional significance of DKK3 in the regulation of post-MI remodelling and its underlying mechanisms. MI was induced by surgical left anterior descending coronary artery ligation in transgenic mice expressing cardiac-specific DKK3 and DKK3 knockout (KO) mice as well as their non-transgenic and DKK3(+/+) littermates. Our results demonstrated that after MI, mice with DKK3 deficiency had increased mortality, greater infarct size, and exacerbated left ventricular (LV) dysfunction. Significantly, at 1 week post-MI, the hearts of DKK3-KO mice exhibited increased apoptosis, inflammation, and LV remodelling compared with the hearts of their DKK3(+/+) littermates. Conversely, DKK3 overexpression led to the opposite phenotype after infarction. Similar results were observed in cultured neonatal rat cardiomyocytes exposed to hypoxia in vitro. Mechanistically, DKK3 promotes cardioprotection by interrupting the ASK1-JNK/p38 signalling cascades. In conclusion, our results indicate that DKK3 protects against the development of MI-induced cardiac remodelling via negative regulation of the ASK1-JNK/p38 signalling pathway. Thus, our study suggests that DKK3 may represent a potential therapeutic target for the treatment of heart failure after MI.

Cardiospecific CD36 suppression by lentivirus-mediated RNA interference prevents cardiac hypertrophy and systolic dysfunction in high-fat-diet induced obese mice.

BACKGROUND: Fatty acid (FA) catabolism abnormality has been proved to play an important role in obesity-related cardiomyopathy. We hypothesized that cardiospecific suppression of CD36, the predominant membrane FA transporter, would protect against obesity-related cardiomyopathy. METHODS: Four-wk-old male C57BL/6 J mice were fed with either high-fat-diet (HFD) or control-normal-diet for 2 wk. Then they were subjected to intramyocardial injection with recombinant lentiviral vectors containing short hairpin RNAs to selectively downregulate the expression of either cardiac CD36 or irrelevant gene by RNA interference. After a 10-wk continuation of the diet, biochemical, functional, morphological, histological, metabolic and molecular profiles were assessed. RESULTS: HFD administration elicited obesity, cardiac hypertrophy and systolic dysfunction accompanied with elevated serum levels of blood urea nitrogen (BUN), creatinine, fasting serum glucose (FSG), total cholesterol (TC) and triglyceride. Additionally, HFD consumption promoted lipid accumulation and reactive oxygen species (ROS) generation in the cardiomyocytes. Cardiospecific CD36 inhibition protected against HFD induced cardiac remodeling by decreasing heart/body weight ratio, increasing left ventricular (LV) ejection fraction and fractional shortening as well as normalizing LV diameter, without influencing body weight gain. Inhibition of cardiac CD36 also mitigated obesity induced alteration in BUN, creatinine and triglyceride, but had no effect on FSG or TC. Moreover, cardiospecific CD36 deficiency corrected myocardial lipid overaccumulation and intracellular ROS overproduction that were induced by HFD feeding. CONCLUSIONS: Cardiospecific CD36 inhibition protects against the aggravation of cardiac functional and morphological changes associated with HFD induced obesity. CD36 represents a potential therapeutic target for obesity cardiomyopathy.

QT hysteresis index improves the power of treadmill exercise test in the screening of coronary artery disease.

BACKGROUND: QT hysteresis phenomenon exists in healthy subjects, and is more exaggerated in patients with coronary artery disease (CAD) and long QT syndrome. The purpose of this study was to establish an appropriate method to evaluate the magnitude of QT hysteresis, and assess the value of QT hysteresis index in the treadmill exercise test (TET) in predicting CAD. METHODS AND RESULTS: A total of 138 subjects with suspected CAD and referred for TET and selective coronary angiography (SCA) were divided into positive (n=77) and negative (n=61) SCA groups. Dynamic ECG were recorded during TET. QT/RR curves were constructed and QTp (Q-Tpeak) and QTe (Q-Tend) hysteresis indices were calculated for each subject. SYNTAX score in the positive SCA group was determined. The QTp and QTe hysteresis indices in the positive SCA group were significantly higher than in the negative SCA group. The combination of QTe hysteresis index and conventional TET criteria had the highest sensitivity and negative predictive value according to receiver operating characteristic curve, and was an independent predictor on multivariate logistic regression. QT hysteresis indices significantly correlated with SYNTAX score in the positive SCA group. CONCLUSIONS: QTe hysteresis index enhances the specificity of predicting CAD in TET. It improves the diagnostic value of TET for CAD significantly when combined with conventional criteria and is associated with the severity of CAD.

Heart rate patterns of captive Asian elephant (Elephas maximus) in their natural habitat at Wild Elephant Valley, Xishuangbanna of China.

There are few studies on the changes of heart rate of the Asian elephant (Elephas maximus), one of the largest tropical terrestrial mammals, with its self-factors and external environment. By measuring the heart rate of 35 Asian elephants, ranging in age from 4 months to 52 years, using a non-invasive electrocardiogram sensor in their natural habitat at Wild Elephant Valley, Xishuangbanna of China, we found factors that significantly influenced the HR were season, phase of the day, age, body weight, and the interaction between some of the above factors. We also observed that Asian elephants had lower resting heart rate in the morning of hot season than the cold and mild season, and the differences were significant, but the heart rate increased to similar levels in the afternoon regardless of the season. HR also decreased with age in all seasons and phases of the day. However, there was no significant effect of sex. This study reveals the adaptability of Asian elephant to tropical environment, and provides a basic reference for heart rate of Asian elephant under various natural conditions.

Carotid Baroreceptor Stimulation Improves Pulmonary Arterial Remodeling and Right Ventricular Dysfunction in Pulmonary Arterial Hypertension.

Autonomic nervous system imbalance is intricately associated with the severity and prognosis of pulmonary arterial hypertension (PAH). Carotid baroreceptor stimulation (CBS) is a nonpharmaceutical intervention for autonomic neuromodulation. The effects of CBS on monocrotaline-induced PAH were investigated in this study, and its underlying mechanisms were elucidated. The results indicated that CBS improved pulmonary hemodynamic status and alleviated right ventricular dysfunction, improving pulmonary arterial remodeling and right ventricular remodeling, thus enhancing the survival rate of monocrotaline-induced PAH rats. The beneficial effects of CBS treatment on PAH might be mediated through the inhibition of sympathetic overactivation and inflammatory immune signaling pathways.

Gut Microbiome Variation Along A Lifestyle Gradient Reveals Threats Faced by Asian Elephants.

The gut microbiome is closely related to host nutrition and health. However, the relationships between gut microorganisms and host lifestyle are not well characterized. In the absence of confounding geographic variation, we defined clear patterns of variation in the gut microbiomes of Asian elephants (AEs) in the Wild Elephant Valley, Xishuangbanna, China, along a lifestyle gradient (completely captive, semicaptive, semiwild, and completely wild). A phylogenetic analysis using the 16S rRNA gene sequences highlighted that the microbial diversity decreased as the degree of captivity increased. Furthermore, the results showed that the bacterial taxon WCHB1-41_c was substantially affected by lifestyle variations. qRT-PCR analysis revealed a paucity of genes related to butyrate production in the gut microbiome of AEs with a completely wild lifestyle, which may be due to the increased unfavorable environmental factors. Overall, these results demonstrate the distinct gut microbiome characteristics among AEs with a gradient of lifestyles and provide a basis for designing strategies to improve the well-being or conservation of this important animal species.

Carotid baroreceptor stimulation prevents oxidative stress by inhibiting MAO-A and prevents cardiac remodeling in obese rats.

OBJECTIVE: Sympathetic nervous system overactivation and abnormal lipid metabolism are featured in obesity and may lead to cardiac remodeling. The effects of carotid baroreceptor stimulation (CBS) on cardiac remodeling in obese rats and the underlying mechanisms were explored. METHODS: An obesity model was induced by 16-week high-fat diet feeding. A CBS device was implanted at the 8th week. Body weight and blood pressure measurements, electrocardiography, echocardiography, and glucose and insulin tolerance tests were conducted before sampling. Plasma analysis and histological and biological analyses of left ventricle were also performed. Neonatal rat cardiomyocytes cocultured with 3T3-L1 in transwell chambers were used to investigate the mechanisms. RESULTS: CBS alleviated several manifestations of obesity, including increased body weight, high blood pressure, hyperlipidemia, and enhanced sympathetic activity. In obese hearts, norepinephrine levels decreased, and the monoamine oxidase A (MAO-A) and reactive oxygen species level increased; these changes, as well as cardiac fibrosis, lipid metabolic disorders, and heart dysfunction, were inhibited by CBS. Neonatal rat cardiomyocytes incubated with norepinephrine showed MAO-A upregulation, increased reactive oxygen species levels, lipid metabolic disorders, and inflammatory response, which were inhibited by clorgyline, a selective MAO-A inhibitor. CONCLUSIONS: CBS effectively suppresses sympathetic nervous system activity and oxidative stress mediated by MAO-A and prevents cardiac remodeling in obese rats.

Fecal Metagenomics Study Reveals That a Low-Fiber Diet Drives the Migration of Wild Asian Elephants in Xishuangbanna, China.

The rare northward migration of wild Asian elephants in Xishuangbanna, China, has attracted global attention. Elephant migration is a complex ecological process, and the factors driving this long-distance migration remain elusive. In this study, fresh fecal samples were collected from both captive and wild Asian elephants, along with breastfed calves residing within the Wild Elephant Valley of Xishuangbanna. Our aim was to investigate the relationship between diet, gut microbiota, and migration patterns in Asian elephants through comprehensive metagenomic sequencing analyses. Among the breastfed Asian elephant group, Bacteroidales and Escherichia emerged as the dominant bacterial taxa, while the primary carbohydrate-active enzymes (CAZymes) enriched in this group were GH2, GH20, GH92, GH97, GH38, GH23, and GH43, aligning with their dietary source, namely breast milk. The bacterial taxa enriched in captive Asian elephants (CAEs) were mainly Butyrivibrio, Treponema, and Fibrobacter, and the enriched lignocellulose-degrading enzymes mainly included GH25, GH10, GH9, and cellulase (EC 3.2.1.4). These findings are consistent with the high-fiber diet of captive elephants. In contrast, the main bacterial taxa enriched in wild Asian elephants (WAEs) were Ruminococcus and Eubacterium, and the enriched CAZymes included GH109, GH20, GH33, GH28, GH106, and GH39. The abundance of lignocellulose-degrading bacteria and CAZyme content was low in WAEs, indicating challenges in processing high-fiber foods and explaining the low-fiber diet in this group. These findings suggest that wild elephant herds migrate in search of nutritionally suitable, low-fiber food sources.

Advances in basic and translational research in atrial fibrillation.

Atrial fibrillation (AF) is a very common cardiac arrhythmia with an estimated prevalence of 33.5 million patients globally. It is associated with an increased risk of death, stroke and peripheral embolism. Although genetic studies have identified a growing number of genes associated with AF, the definitive impact of these genetic findings is yet to be established. Several mechanisms, including electrical, structural and neural remodelling of atrial tissue, have been proposed to contribute to the development of AF. Despite over a century of exploration, the molecular and cellular mechanisms underlying AF have not been fully established. Current antiarrhythmic drugs are associated with a significant rate of adverse events and management of AF using ablation is not optimal, especially in cases of persistent AF. This review discusses recent advances in our understanding and management of AF, including new concepts of epidemiology, genetics and pathophysiological mechanisms. We review the current status of antiarrhythmic drug therapy for AF, new potential agents, as well as mechanism-based AF ablation. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.

[Value of QT hysteresis during treadmill exercise test for diagnosing coronary heart disease].

OBJECTIVE: To investigate the value of QT hysteresis index during treadmill exercise test (TET) in diagnosing coronary heart disease (CHD). METHODS: One hundred consecutive patients suspected for CHD were referred for TET and selective coronary angiography (CAG). Patients were divided into positive [n = 55, age (56.0 ± 7.9) years] and negative [n = 45, age (53.2 ± 6.7) years] group based on their CAG results. For each TET recording, 50 points were selected for the RR, QTp, and QTe interval measurements. QTp and QTe interval was plotted against corresponding RR interval. QT/RR curve was constructed by connect all point, QT hysteresis index was calculated for each patient. RESULTS: The QTp [(22.4 ± 10.3) ms vs. (6.7 ± 4.6) ms, P < 0.001] and QTe [(27.1 ± 11.1) ms vs. (7.6 ± 4.6) ms, P < 0.001] hysteresis index of patients in positive group were significantly higher than those in negative group. The sensitivity of QTp and QTe hysteresis index for diagnosing CHD was 89.1% (49/55) and 94.5% (52/55), respectively, and the specificity was 82.2% (37/45) and 80.0% (36/45), respectively. If the patient fulfilled both the classical TET and QT hysteresis criteria, the sensitivity for diagnosing CHD increased to 94.3% (33/35, QTp) and 94.6% (35/37, QTe), and the specificity were both 100% (26/26, 26/26). Moreover, QTp (r = -0.399, P < 0.001) and QTe (r = -0.547, P < 0.001) hysteresis index highly correlated to Duke treadmill score. CONCLUSION: QT hysteresis index is useful parameter for CHD diagnosis and which could improve the diagnostic value of TET for CHD in combination with the classical TET criteria for diagnosis of CHD.

Elephant Endotheliotropic Herpesvirus 1, 4 and 5 in China: Occurrence in Multiple Sample Types and Implications for Wild and Captive Population Surveillance.

Elephant endotheliotropic herpesviruses (EEHVs) are important causes of death in both captive and wild Asian elephants (Elephas maximus). Nothing is known about the prevalence of EEHVs in wild or domestic elephants in China. To determine if EEHVs are present in elephants in China, 126 wild elephants from three populations and 202 captive individuals from zoos (n = 155) and the Wild Elephant Valley (n = 47) were screened using semi-nested polymerase chain reaction assays with EEHV-redundant and EEHV1/4/5-specific primers. EEHV1B and EEHV4 were detected in samples from both wild (EEHV1B:8/126; EEHV4:2/126) and captive (EEHV1B:5/155; EEHV4:9/155) elephants, while EEHV1A (six cases) and EEHV5 (one case) were only present in the captive elephants from the Wild Elephant Valley. EEHV1 was detected in blood and trunk and oral swabs; EEHV4 was detected in trunk and oral swabs as well as feces; EEHV5 was found in trunk and oral swabs. No significant age or sex association with EEHV1A, EEHV1B, or EEHV5 positivity was observed. An age association with EEHV4 positivity was found, with all unweaned elephants being EEHV4 positive, but an association with the sex of the elephant was not observed. These findings represent the first documentation of EEHV presence in captive and wild elephants in China. These findings also document EEHV1B and EEHV4 shedding in feces and demonstrate the utility of fecal screening as a tool for investigating EEHV4 infection in wild populations of elephants. It is recommended that EEHV testing be included in surveillance programs for captive and wild elephants in China.

Identification of CaMKII phosphorylation sites in Connexin43 by high-resolution mass spectrometry.

Connexin43 (Cx43) is a major cardiac gap junction channel protein required for normal electrical and contractile activity. Gap junction channel assembly, function, and turnover are regulated by phosphorylation under both normal and disease conditions. The carboxyl terminus (CT) of Cx43 contains numerous amino acid residues that are phosphorylated by protein kinases. However, our knowledge of the specific residues and kinases involved is incomplete. The objective of this study was to identify amino acid residues in the Cx43-CT that are targets of the multifunctional protein kinase, Ca(2+)/calmodulin protein kinase II (CaMKII), an enzyme known to play critical roles in Ca(2+) homeostasis, transcription, apoptosis, and ischemic heart disease. We subjected fusion protein containing the Cx43-CT to phosphorylation by CaMKII in vitro, digestion with Lys-C and trypsin followed by enrichment for phosphorylated peptides using TiO(2), and analysis in an LTQ XL Orbitrap with collision-induced dissociation and electron transfer dissociation. We deduced the sites of modification by interpreting tandem spectra from these "orthogonal" methods of gas phase peptide fragmentation. We have identified 15 serine residues, including one novel site, in the Cx43-CT that are phosphorylated by CaMKII, the activity of which may be important in regulating Cx43 in normal and diseased hearts.