DFT Study on the Janus ZrSSe Monolayer for Its Potential Application in NO Gas Sensing.

The growth of industry has resulted in increased global air pollution, necessitating the urgent development of highly sensitive gas detectors. In this work, the adsorption of the Janus ZrSSe monolayer for CO, CO2, NH3, NO, NO2, and O2 was studied by first-principles calculations. First, the stability of the ZrSSe monolayer is confirmed through calculations of cohesive energy and AIMD simulations. Furthermore, the calculations indicate that the Se layer exhibits higher selectivity and sensitivity toward gas molecules compared to the S layer. Specifically, among the gases adsorbed on the Se layer, NO has the shortest adsorption distance (1.804 Å), the lowest adsorption energy (-0.424 eV), and the greatest electron transfer (0.098 e). Additionally, density of states analysis reveals that adsorption of NO, NO2, and O2 on the Janus ZrSSe monolayer can induce a transition from a nonmagnetic to a magnetic state. The adsorption of NO not only alters the magnetic state but also induces a transition from a semiconductor to metal, which is highly advantageous for gas sensing applications. There results suggest that the Janus ZrSSe monolayer has the potential to serve as a highly sensitive detector for NO gas.

Effects of ceramsite derived from sewage sludge combined with the O3-FeCl3/PAM process on the dewatering of waste-activated sludge and investigation of dewatering mechanisms.

The high water content of waste-activated sludge restricts the subsequent disposal of sludge. The dehydration properties of O3, ferric chloride (FeCl3)/polyacrylamide, and sludge ceramsite sand (SCS) were studied. Simultaneously, the effect of combining the three was investigated to support the deep dehydration of waste-activated sludge. Experimental results showed that with13.42 mg/(g dry solids (DS)) of O3, 109.89 mg/(g DS) of FeCl3, and 100 mesh dosage of 70% DS of sludge ceramsite on weight, the highest sludge net yield was 7.13 kg/(m2·h) and the minimum specific resistance to filtration of sludge cake was 1.02 × 1012 (m/kg). Compared with the compressibility of the raw sludge, the compressibility of the sludge cake decreased by 37.48%. Moreover, the YN (net yield) increased by 73.55%. The results demonstrate that the structure of cracking, flocculation, and hydrophobic framework is the mechanism of sludge dewatering in this combined process. This combined treatment process provides a new perspective for the realization of deep dewatering of sludge and is anticipated to be a successful sludge dehydration method.

Curcumin attenuates intracerebral hemorrhage-induced neuronal apoptosis and neuroinflammation by suppressing JAK1/STAT1 pathway.

Intracerebral hemorrhage (ICH) is a kind of fatal stroke with the highest mortality and morbidity in the world. To date, there is no effective treatment strategy for ICH. Curcumin, a major active ingredient of Curcuma longa L., possesses a potential anti-inflammatory activity in many types of disease. In the current study, the mechanism underlying curcumin attenuated ICH-induced neuronal apoptosis and neuroinflammation was explored. Herein, we studied that curcumin decreased brain edema and improved neurological function by using brain edema measurement, assessment of neurological-deficient score, immunofluorescence, and Western blotting analyses after ICH. The results showed that curcumin improved ICH-induced neuronal apoptosis and neuroinflammation. Functionally, the polarization of microglia was assessed by immunofluorescence and Western blotting analyses after ICH in the absence or presence of curcumin. The results suggested that the M1-type microglia were activated after ICH, while the effect was blocked by curcumin treatment, suggesting that curcumin alleviates the neuroinflammation and apoptosis of neurons by suppressing the M1-type polarization of microglia. Mechanically, M1 polarization of microglia was regulated by JAK1/STAT1, and the activation of JAK1/STAT1 was blocked by curcumin. Meanwhile, the protective function of curcumin can be blocked by RO8191, an activator of JAK1. Taken together, our study suggested that curcumin improved the ICH-induced brain injury through alleviating M1 polarization of microglia/macrophage and neuroinflammation via suppressing the JAK1/STAT1 pathway.

Regulation of eotaxin expression in skin allergic diseases.

Introduction: As a key chemotactic factor during Eos recruitment on the allergic inflammation site, eotaxin is regarded as one of the important therapeutic targets. Aim: To address the expression and regulation mechanism of eotaxin, which constitutes an important procedure in skin allergic disease and a target for drug therapy. Material and methods: An allergic contact dermatitis (ACD) model of mouse was established. Immunohistochemical method (ICH) and flow cytometry method (FCM) were used to determine the amounts of CD4+ and CD8+ T cells and their ratios. The eotaxin mRNA and protein were evaluated by real-time PCR, ICH and western-blotting method. Nuclear factor-κB (NF-κB) nuclear translocation and STAT6 phosphorylation were studied by EMSA and western-blotting methods. Results: We confirmed that both CD4+ and CD8+ T cells in mouse blood and tissue increased during the allergic process, FBs was the main source for eotaxin under the allergic condition. Both TNF-α and IL-4 showed synergic effects on the up-regulation of eotaxin mRNA and protein in KC and FBs. Eotaxin can be expressed via NF-κB and STAT6 transcription after KC and FBs were stimulated by TNF-α and IL-4. Conclusions: The obvious up-regulation of eotaxin expression in skin tissue of the mouse ACD model was confirmed, the exact expression site and dynamic process was determined both in vivo and in vitro. The eotaxin expression ability of FBs outperformed that of KC, and eotaxin expression can be regulated by TNF-α and IL-4 via NF-κB and STAT6. The overall findings may pave the way for discovering targets for new drugs and new therapeutic drugs for treating allergic diseases.

Online high-pH reversed-phase liquid chromatography × low-pH reversed-phase liquid chromatography tandem electrospray ionization mass spectrometry combined with pulse elution gradient in the first dimension for the analysis of alkaloids in Macleaya cordata (willd.) R. Br.

An online high-pH reversed-phase liquid chromatography× low-pH reversed-phase liquid chromatography tandem electrospray ionization mass spectrometry combined with pulse elution gradient in the first dimension was constructed to separate and identify alkaloids from Macleaya cordata (willd.) R. Br. The modulation was performed by using a dual second dimensional columns interface combined with a make-up dilution pump, which is responsible for dilution and neutralization of the first dimensional effluent, and the dual second dimensional columns integrated the trapping and the separation function to reduce the second dimension system dead volume. Taking advantage of the dissociable characteristics of alkaloids, mobile phases with different pH values were applied in the first dimension (pH 9.0) and the second dimension (pH 2.6) to improve the orthogonality of two-dimension separation. Besides, the pulse elution gradient in first dimension and second dimensional gradient were carefully optimized and much better separation was achieved compared to the separation with the traditional two-dimensional liquid chromatography approach. Finally, mass measurement was performed for alkaloids in M. cordata (willd.) R. Br. by coupling proposed two-dimensional liquid chromatography system with triple quadrupole mass spectrometry, and 39 alkaloids were successfully identified by comparing the obtained result with the former reported results.

A new benzofuran derivative from Nicotiana tabacum.

A new benzofuran derivative, methyl 3-acetyl-7-hydroxy-6-methoxy-2-methylbenzofuran-4-carboxylate (1), and a known compound pyrrolezanthine (2), were isolated from leaves of Nicotiana tabacum. Compound 1 was elucidated by means of spectroscopic methods, as well as X-ray diffraction. Both compounds 1 and 2 exhibited moderate inhibitory activities on human cancer cell lines.

Calmodulin of the tropical sea cucumber: Gene structure, inducible expression and contribution to nitric oxide production and pathogen clearance during immune response.

Calmodulin (CaM) is an essential second messenger protein that transduces calcium signals by binding calcium ions (Ca(2+)) and modulating its interactions with various target proteins. In contrast to vertebrates, where CaM is well established as a cofactor for Ca(2+)-dependent physiological and cellular functions including host defense, there is a paucity of understanding on CaM in invertebrates (such as echinoderms) in response to immune challenge or microbial infections. In this study, we obtained and described the gene sequence of CaM from the tropical sea cucumber Stichopus monotuberculatus, a promising yet poorly characterized aquacultural species. mRNA expression of StmCaM could be detected in the intestine and coelomic fluid after Vibrio alginolyticus injection. Transcriptional and translational expression of StmCaM was inducible in nature, as evidenced by the expression patterns in primary coelomocytes following Vibrio challenge. This response could be mimicked by the Vibrio cells membrane components or lipopolysaccharides (LPS), and blocked by co-treatment of the LPS-neutralizing agent polymyxin B (PMB). Furthermore, inhibition of CaM activity by incubation with its inhibitor trifluoroperazine dihydrochloride (TFP) blunted the production of Vibrio-induced nitric oxide (NO) and augmented the survival of invading Vibrio in coelomocytes. Collectively, our study here supplied the first evidence for echinoderm CaM participation in innate immunity, and provided a functional link between CaM expression and antibacterial NO production in sea cucumber.

Cloning of sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) gene from white shrimp, Litopenaeus vannamei and its expression level analysis under salinity stress.

Sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) is an intracellular membrane bound enzyme that utilizes the free energy of ATP to transport Ca(2+) against a concentration gradient. In the present study, a new SERCA gene (LvSERCA) from white shrimp (Litopenaeus vannamei) was cloned using suppression subtractive hybridization and rapid amplification of cDNA ends. The full-length cDNA of LvSERCA contained an open reading frame of 3,009 bp coding for 1,002 amino acids with a calculated molecular weight of approximately 109.8 kDa. The identity analysis of the amino acid sequence of LvSERCA showed that it is highly conserved with 10 transmembrane α-helices, one P-domain, one A-domain and one N-domain. The phylogenetic analysis revealed that LvSERCA is similar to other Arthropoda SERCA proteins. The mRNA levels of LvSERCA under salinity stress (3 and 40 g L(-1)) were analyzed by reverse transcription PCR and quantitative real-time PCR. The results showed that LvSERCA was expressed in all tissues detected. LvSERCA mRNA levels were significantly higher under hyper-salinity than hypo-salinity. These results highlight that Ga(2+)-ATPase plays an essential role in adjustment salinity stress, which may be useful for selective breeding of L. vannamei.

Crocin Alleviates Intracerebral Hemorrhage-Induced Neuronal Ferroptosis by Facilitating Nrf2 Nuclear Translocation.

Intracerebral hemorrhage (ICH) is the deadliest type of stroke. Oxidative stress was considered to play an important role in ICH-induced secondary injury. Crocin, the main compound isolated from Crocus sativus L., possesses a potential anti-oxidative function in many types of diseases including ICH. In the current study, the protective role of crocin in ICH-induced brain injury was investigated in the ICH model. The ICH-induced brain edema and neurological deficits were analyzed by brain edema measurement and neurological testing. The superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) activity and the content of malondialdehyde (MDA) were assessed by a total superoxide dismutase assay kit. The expressions of ferroptosis-related genes were verified by quantitative real-time PCR (qPCR) and western blotting. The ICH-induced brain edema and neurological deficits were significantly decreased after treatment with crocin. Moreover, the SOD and GSH-px activities were obviously increased in the ICH with crocin-treated group compared with the ICH group, while the content of MDA was markedly decreased after treatment with crocin. Crocin inhibited ferroptosis of neuron cells, as evidenced by increased Fe2+ concentration and the expression of GPX4, FTH1, and SLC7A11. Mechanistically, crocin treatment increased the expression and nuclear translocation of Nrf2. Our data suggest that crocin alleviates intracerebral hemorrhage-induced neuronal ferroptosis by facilitating Nrf2 nuclear translocation.

Direct adsorption sampling and ambient mass spectrometry analysis of tobacco smoke with porous paper strips.

Chemical analysis of atmospheric aerosols by conventional analytical methods is usually required to perform complicated and time-consuming sample preparation processes. In recent decades, ambient ionization mass spectrometry (AI-MS) methods have been proven to be simple, rapid, and effective analytical tools for direct analysis of various complex samples. In this work, we applied porous paper filters for direct adsorptive sampling of tobacco smoke, and then the sampled paper filters were performed the emitters of the paper spray ionization (PSI) device. An auto-sampling device was made to control the generation and collection of tobacco smoke. Nicotine, the typical compound of tobacco smoke, was used to optimize the key conditions of auto-sampling. Moreover, different types of tobacco smoke were also compared with multivariate variable analysis, and the makers of tobacco smoke from different sources of tobacco smoke were investigated. By using this method, direct sampling and analysis of a single tobacco sample can be completed within minutes. Overall, our results show that PSI-MS is a powerful tool that integrates collection, extraction, ionization, and identification analytes in smoke.

Toonamicrocarpavarin, a new tirucallane-type triterpenoid from Toona Ciliata.

Toonamicrocarpavarin (1), a new tirucallane-type triterpenoid, along with eight known ones, piscidinol A (2), toonaciliatavarin E (3), toonayunnanin A (4), 7-acetyneotrichilenone (5), hispidol A (6), odoratone (7), phellochin (8), toonaciliatavarin D (9), were isolated from T. ciliata. Their structures were identified on the basis of ESIMS, HREIMS and 1 D/2D NMR analysis. The cytotoxic activity of the new compound was also evaluated. All compounds were obtained from T. ciliata for the first time, which plays an important role in chemotaxonomy of the plant T. ciliata.

SLC25A10 performs an oncogenic role in human osteosarcoma.

Osteosarcoma is one of the most common primary malignant bone tumors in adolescents. It is associated with high risk of relapse and the outcomes of patients with high-grade osteosarcoma remain poor. Therefore, additional studies investigating the molecular mechanisms involved in tumor initiation, growth, migration and invasion of osteosarcoma are necessary. In the present study, the protein levels of solute carrier family 25 member 10 (SLC25A10) were increased in osteosarcoma tissue, compared with normal bone tissue. In patients with osteosarcoma, high expression levels of SLC25A10 were associated with poor clinicopathological parameters, including metastasis, clinical Enneking stage, relapse-free survival and overall survival rates. Short hairpin RNA knockdown of SLC25A10 significantly suppressed cell proliferation as determined by cell counting, MTT assay and cell colony formation assays. In addition, SLC25A10 knockdown caused an increase in apoptosis and a decrease in mitosis in osteosarcoma cells. Cyclin E1 (CCNE1) was positively regulated by SLC25A10, while P21 and P27 were negatively regulated by SLC25A10. Therefore, SLC25A10 may play an oncogenic role in human osteosarcoma, which could be mediated by CCNE1, P21 and P27.

[Minimally invasive external fixation of humeral supracondylar angular rotation center for the treatment of cubitus varus deformity in adolescents].

OBJECTIVE: To investigate clinical effect of minimally invasive osteotomy and external fixation with the center of roration of angulation (CORA) in treating cubitus varus in adolescents. METHODS: From August 2013 to August 2017, 15 patients with cubitus varus caused by supracondylar fracture of humerus were treated with minimally invasive osteotomy and external fixation with the CORA. Among them, including 9 males and 6 females; 11 patients on the left side and 4 patients on the right side; aged from 13 to 16 years old with an average of 14.5 years old. The time from injury to operation was for 6 to 10 years with an average of 7.5 years. Five patients had a history of recurrence after cubitus varus surgery. Correction time. fracture healing time, carrying angle were observed, Laupattarakasem standard was used to evaluate clinical effect. RESULTS: All patients were followed up from 12 to 30 months with an average of 24 months; correction time ranged from 3 to 5 weeks with an average of 4 weeks; fracture healing time ranged from 4 to 6 months with an average of 5 months; carrying angle before operation ranged from -12° to -23°, and improved 9° to 14° after operation. According to Laupattarakasem evaluation criteria, 11 patients got an excellent result, 3 good and 1 fair. CONCLUSIONS: Minimally invasive osteotomy and external fixation with CORA in treating cubitus varus deformity in adolescents has advantages of less trauma, less blood loss, earlier exercise, speed and angle of correction could controlled without hospitalized for fixation.

Three new C23 steroids from the leaves and stems of Nicandra physaloides.

Nicandra physaloides is a medicinal and edible plant and has been used as traditionally herbal medicine to treat various diseases in folk. Its characteristic withanolides, a kind of ergostane-type steroids, are reported to display plentiful biological activities that many explain the effect of N. physaloides to some extent. Thus, to further find bioactive steroids, the stems and leaves of N. physaloides were investigated and three new C23 steroids, nic-physatones I-J (1-2), and nic-physatone S (3), together with a known C25 steroid, nic 17 (4), were isolated. Their structures were elucidated by extensive 1D NMR and 2D NMR (HSQC, HMBC, 1H-1H COSY, and ROESY), UV and MS analyses. Compounds 1-3 possess a rare C23 steroid skeleton. Among them, compound 3 represented the first example of a C23 steroid featuring a benzene ring (D ring). The isolated compounds showed no cytotoxic activity.

Serum iron levels are an independent predictor of in-hospital mortality of critically ill patients: a retrospective, single-institution study.

OBJECTIVE: This study aimed to examine the relationship between serum iron levels and in-hospital mortality in critically ill patients. METHODS: We retrospectively studied 250 critically ill patients who received treatment at the intensive care unit between June 2015 and May 2017. Blood chemistry and hepatic and renal function were measured. Kaplan-Meier survival curves were plotted according to serum iron levels. Correlations between serum iron levels and other variables were analyzed. RESULTS: A total of 165 (66.0%) patients had abnormally low serum iron levels (<10.6 µmol/L). Patients who died during hospitalization had markedly higher Acute Physiology and Chronic Health Evaluation II scores and significantly lower serum iron levels compared with those who survived. Cumulative survival was significantly lower in patients with low serum iron levels than in those with normal serum iron levels in subgroup analysis of older patients (n = 192). Multivariate regression analysis showed that, after adjusting for relevant factors, low serum iron levels remained an independent risk for in-hospital mortality (odds ratio 2.014; 95% confidence interval 1.089, 3.725). CONCLUSIONS: Low serum iron levels are present in a significant proportion of critically ill patients and are associated with higher in-hospital mortality, particularly in older patients.

Early increase of neutrophil-to-lymphocyte ratio predicts 30-day mortality in patients with spontaneous intracerebral hemorrhage.

AIMS: To examine whether early rise of neutrophil-to-lymphocyte ratio (NLR) after patient hospitalization correlates with 30-day mortality in patients with spontaneous intracerebral hemorrhage (ICH). METHODS: This retrospective study included all patients receiving treatment for spontaneous ICH between January 2015 and September 2016 at the Jiading District Central Hospital Affiliated Shanghai University of Medicine & Health Sciences in Shanghai, China. NLR was determined at admission (T1), at 24-48 hours (T2) and 5-7 days (T3). NLR and clinicopathologic features were compared between those who survived for >30 days vs not. Multivariate regression was used to identify risk factors for 30-day mortality. RESULTS: A total of 275 subjects were included in the analysis: 235 survived for at least 30 days; the remaining 40 subjects died within 30 days. The patients who died within 30 days had higher ICH score, larger ICH volume, and lower GCS score (all P < 0.05). In comparison with the baseline (NLRT1 ), NLR at 24-48 hours (NLRT2 ) and 5-7 days (NLRT3 ) was significantly higher in patients who died within 30 days (P < 0.05), but not in patients surviving for >30 days. In the multivariate analysis, the 30-day mortality was associated with both NLRT2 (OR 1.112, 95%CI 1.032-1.199, P = 0.006) and NLRT3 (OR 1.163, 95%CI 1.067-1.268, P = 0.001). Spearman correlation analysis showed that both NLRT2 and NLRT3 correlated inversely with GCS score and positively with ICH score and ICH volume at the baseline. CONCLUSIONS: Early rise of NLR predicts 30-day mortality in patients with spontaneous ICH.

Neutrophil-to-Lymphocyte Ratio Is an Independent Predictor of 30-Day Mortality of Intracerebral Hemorrhage Patients: a Validation Cohort Study.

In a previous study in patients with intracranial hemorrhage (ICH), we found an association between high neutrophil-to-lymphocyte ratio (NLR) with poor short-term mortality. In the current study, this preliminary finding was validated using an independent patient cohort. A total of 181 ICH patients (from January 2016 to December 2017) were included. Diagnosis was confirmed using computed tomography (CT) in all cases. Patient survival (up to 30 days) was compared between subjects with high NLR (above the 7.35 cutoff; n = 74) versus low NLR (≤ 7.35; n = 107) using Kaplan-Meier analysis. A multivariate logistic regression was performed to identify factors that influenced the 30-day mortality. Correlation between NLR with other relevant factors (e.g., C-reactive protein (CRP) and fibrinogen) was examined using Spearman correlation analysis. The 30-day mortality was 19.3% (35/181) in the entire sample, 37.8% (28/74) in the high-NLR group, and 6.5% (7/107) in the low-NLR group (P < 0.001). In comparison to the low-NLR group, the high-NLR group had higher rate of intraventricular hemorrhage (29.7 vs. 16.8%), ICH volume (median 23.9 vs. 6.0 cm3) and ICH score (median 1.5 vs. 0), and lower GCS score (9.4 ± 4.5 vs. 12.9 ± 3.2). An analysis that divided the samples into three equal parts based on NLR also showed increasing 30-day mortality with incremental NLR (1.6, 15.0, and 41.7% from lowest to highest NLR tertile, P for trend < 0.001). Kaplan-Meier curve showed higher 30-day mortality in subjects with high NLR than those with low NLR (P < 0.001 vs. low-NLR group, log-rank test). High NLR (> 7.35) is associated with poor short-term survival in acute ICH patients.

Dynamic Change of Red Cell Distribution Width Levels in Prediction of Hospital Mortality in Chinese Elderly Patients with Septic Shock.

BACKGROUND: The normal range of red cell distribution width (RDW) level is <15%. Several studies have indicated that a high RDW level was associated with mortality in critically ill patients, and the patients with a high RDW level need increased focus in clinical practice. In view of the difficulty in defining the specific value of high RDW level, the key is to focus on the patient with the level beyond the normal upper limit. This study aimed to determine whether dynamic change of RDW levels, rather than the level itself, is predictive of death in elderly patients with septic shock when RDW level is beyond 15%. METHODS: Between September 2013 and September 2015, the elderly septic shock patients with RDW level beyond 15% were enrolled in this study. The RDW levels were measured at enrollment (day 1), and days 4 and 7 after enrollment. Sequential Organ Failure Assessment (SOFA) scores were recorded simultaneously. RESULTS: A total of 45 patients, including 32 males and 13 females, were included in the final analysis. Based on their hospital outcomes, these patients were divided into the survivor group (n = 26) and the nonsurvivor group (n = 19). There were no significant differences in age, gender, body mass index, initial level of RDW, Acute Physiology and Chronic Health Evaluation II scores, and SOFA scores between survivors and nonsurvivors. At days 4 and 7 measurement, both RDW level (median [interquartile range]: day 4: 15.8 [2.0]% vs. 16.7 [2.0]%, P= 0.011; and day 7: 15.6 [1.8]% vs. 17.7 [2.5]%, P= 0.001) and SOFA scores (day 4: 7.0 [4.0] vs. 16.0 [5.0], P< 0.001, day 7: 5.5 [4.0] vs. 17.0 [5.0], P< 0.001) were significantly lower in survivors than those in nonsurvivors. Dynamic changes of RDW and SOFA scores in survivor group were significantly different from those in nonsurvivor group (all P< 0.05). Continuous increase in RDW level was observed in 10 of the 13 nonsurvivors, but only in 3 of the 26 survivors. The level of RDW7 and dynamic changes significantly correlated with their counterparts of SOFA scores (all P< 0.05), whereas the levels of RDW1 and RDW4 had no significant correlation with their counterparts of SOFA scores (all P> 0.05). CONCLUSIONS: Continuous increase in RDW level, rather than the level of RDW itself, was more useful in predicting hospital death in elderly patients with septic shock when the level of RDW was >15%. The dynamic changes of RDW were highly correlated with the SOFA score in the patients.

Protein-imprinted polymer with immobilized assistant recognition polymer chains.

Here we introduce a new method for preparing a protein-imprinted polymer with immobilized assistant recognition polymer chains as an additional element of monomer to create effective recognition sites. In this work the bovine serum albumin was used as template and the template protein was selectively assembled with immobilized assistant recognition polymer chains from their library, numerous limited length polymer chains with randomly distributed recognition sites and immobilizing sites. These assemblies of protein and immobilized assistant recognition polymer chains would be adsorbed by the macro porous adsorbent spheres and immobilized by cross-linking polymerization. After removing the template, binding sites that were complementary to the target protein in size, shape and position of recognition groups were exposed, and their confirmation was preserved by the cross-linked structure. The synthesized imprinted polymer was used to adsorb BSA from protein mixtures, and showed a high selectivity.

Discovery, structural characterization and functional analysis of alpha-2-macroglobulin, a novel immune-related molecule from Holothuria atra.

The non-specific protease inhibitor alpha-2-macroglobulin (A2M) is a key macromolecular glycoprotein that involved in host immune defense against pathogens in vertebrates and invertebrates. However, no research regarding A2M has been developed in echinoderms to date. In this study, the full-length cDNA of A2M was cloned from the sea cucumber (Holothuria atra), which is a tropical species widely distributed along the coasts of the South China Sea and designated HaA2M. HaA2M possesses all three conserved functional domains of known A2M proteins, including the bait region domain, thioester domain and receptor-binding domain. Compared to fish and shrimp A2Ms, the histidine residue from the catalytical regions is well conserved in HaA2M. HaA2M mRNA was predominantly expressed in coelomocytes and, to a lesser extent, in the body wall, intestine and respiratory tree. A2M activity was detected in the coelomic fluids of H. atra. The mRNA expression and activity levels were investigated in the major immune tissues and coelomic fluids of H. atra after challenge with inactivated Vibrio alginolyticus or polyriboinosinic polyribocytidylic acid [Poly (I: C)]. RNA interference (RNAi)-mediated knockdown of HaA2M resulted in a significant reduction of HaA2M gene transcript level (86%). RNAi-mediated silencing of HaA2M gene significantly decreased the A2M activity (38%) and increased the number of viable bacteria (2.8-fold) in the coelomic fluids of H. atra infected by V. alginolyticus. Our study, as a whole, supplied the evidences for HaA2M as an immune-relevant molecule and it might have multiple functions in the innate immune system of H. atra.