The novel chitosan-amphoteric starch dual flocculants for enhanced removal of Microcystis aeruginosa and algal organic matter.

A novel flocculation strategy for simultaneously removing Microcystis aeruginosa and algal organic matter (AOM) was proposed using chitosan-amphoteric starch (C-A) dual flocculants in an efficient, cost-effective and ecologically friendly way, providing new insights for harmful algal blooms (HABs) control. A dual-functional starch-based flocculant, amphoteric starch (AS) with high anion degree of substitution (DSA) and cation degree of substitution (DSC), was prepared using a cationic moiety of 3-chloro-2-hydroxypropyltrimethylammonium chloride (CTA) coupled with an anion moiety of chloroacetic acid onto the backbone of starch simultaneously. In combination of the results of FTIR, XPS, 1H NMR, 13C NMR, GPC, EA, TGA and SEM, it was evidenced that the successfully synthesized AS with excellent structural characteristics contributed to the enhanced flocculation of M. aeruginosa. Furthermore, the novel C-A dual flocculants could achieve not only the removal of >99.3 % of M. aeruginosa, but also the efficacious flocculation of algal organic matter (AOM) at optimal concentration of (0.8:24) mg/L, within a wide pH range of 3-11. The analysis of zeta potential and cellular morphology revealed that the dual effects of both enhanced charge neutralization and notable netting-bridging played a vital role in efficient M. aeruginosa removal.

Inflammation and apoptosis pathways mediated the stress response of Litopenaeus vannamei to acute cold and air exposure during waterless live transportation: Based on ultrastructure and transcriptome.

the combination of acute cold (AC) and waterless duration (WD) constitutes the major environmental stress and induces the damage or even mortality to shrimp L. vannamei during live transport, whereas the responding mechanism to AC + WD at molecular level remains unknown. The present study aims to clarify the responding mechanism of L. vannamei to AC + WD stress by ultrastructural observation and transcriptomic analysis on hepatopancreas tissue. The results showed that the dramatical oxidative stress induced by AC + WD significantly mediated the alteration of amino acids and energy metabolism. Furthermore, KEGG pathway enrichment analysis revealed that the genes including DDO, GOT1, IDH1 and BBOX1 involved in energy metabolism and were significantly down-regulated, while some apoptosis- and inflammation-related genes such as DRONC, AP-1, and COX-2 were significantly up-regulated under AC + WD stress in comparison with those at normal control (all p < 0.05 or 0.01). These findings suggested that metabolic processes mediate the stress-induced damages of L. vannamei during waterless transport. Moreover, the significant overexpression of apoptosis-and inflammation-related proteins, and levels of inflammation cytokines in serum of shrimps strongly demonstrated the implication of inflammation and apoptosis pathways in stress-induced ultrastructural damage. These findings deepen our understanding into the response mechanisms of L. vannamei to AC + WD stress and provide the potential controlling biomarkers for transportation management.

Energy metabolism response of Litopenaeus vannamei to combined stress of acute cold exposure and waterless duration: Implications for physiological regulation and waterless live transport.

Maintaining the homeostasis of energy metabolism is crucial for organism's stress tolerance and survival. Acute cold exposure (AC) and waterless duration (WD) represent the two predominate abiotic stressors during waterless live transport of Litopenaeus vannamei. Although previous reports have explored the physiological response of L. vannamei to combined stress AC + WD, the roles of energy metabolism response in regulation of stress tolerance remains unknown. The present study comparatively examined the variations of energy metabolism-related indicators in hemolymph (cortisol, hemocyanin, glucose and lactate), hepatopancreas and muscle tissues (levels of lactate and glycogen, activities of hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK), lactate dehydrogenase (LDH), succinate dehydrogenase (SDH) and adenosine triphosphatase (ATPase), and ATP levels). Combined stress significantly disturbed the homeostasis of energy metabolism with the increase in levels of hemocyanin, glucose and lactate, and decrease in glycogen and ATP content (P < 0.05). In addition, the activities of HK, PFK, PK, and SDH initially elevated and then decreased with the prolongation of combined stress from 3h to 9h duration, while the activity of lactate dehydrogenase (LDH) remained gradual elevation and ATPase activity decreased in a duration time dependent manner throughout the experiment. These alterations revealed that exposure to combined stress could accelerate anaerobic metabolism at initial stage and inhibit aerobic metabolism in a duration time-dependent manner, following with the reduction of energy biosynthesis and the disturbance of energy metabolism equilibrium. On the other hand, the progressive impairment on hepatopancreas tissue was observed under combined stress. In summary, the deficiency of ATP supply and histopathological injures on hepatopancreas tissue might the underlying mechanisms inducing mortality of L. vannamei during live transport.

Insights into the response mechanism of Litopenaeus vannamei exposed to cold stress during live transport combining untargeted metabolomics and biochemical assays.

Unfavorable conditions severely affect the survival quality of Litopenaeus vannamei (L. vannamei) during live transport and the molecular response mechanism needs to be clarified. In this study, metabolomics combined with conventional assay on physiological and histopathological responses were applied to deepen the understanding of L. vannamei to cold stress and provide. A solid foundation for regulation of transportation management. Physiological and biochemical analysis revealed the significant disturbance of glycolysis in hepatopancreas tissue. Furthermore, metabolomics based on the technique of ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry identified the significantly differential metabolites between acute cold exposure (AC) and normal control (NC) groups. Moreover, KEEG result indicated that the pathways of amino acid, glycerophospholipid, and nuclei acid metabolism and ABC transporters in hepatopancreas were significantly disturbed. Furthermore, histopathology and ultrastructure verified the impairment in hepatopancreas during cold stress. Overall, the concurrent use of metabolomics and biochemical assays was demonstrated to be sensitive and effective in providing new insights into the response mechanism of L. vannamei to cold stress.

Combined stress of acute cold exposure and waterless duration at low temperature induces mortality of shrimp Litopenaeus vannamei through injuring antioxidative and immunological response in hepatopancreas tissue.

High mortality is a frequent occurrence during live transport of shrimp species and the biochemical mechanism remains unknown. This study aimed to explore the influence of combined stress of acute cold exposure (AC) and waterless duration (WD) on survivability and biochemical response of shrimp L. vannamei during live transport. The shrimps in NC and AC groups remained the total survivability throughout the experiment while the shrimps exposed to AC + WD stress exhibited significantly higher mortality since 6h afterwards (P < 0.05) and the median survival time was calculated at 10.46 h. Moreover, the typical combined stress points at AC + WD3h, AC + WD6h and AC + WD9h were assigned for exploring the immunological and antioxidative responses. For immunity response, the total hemocyte counts (THC) decreased with the prolongation of duration time and the activities of non-specific immunity enzymes such as phenol oxidase (PO), acid phosphatase (ACP), alkaline phosphatase (AKP), aspartate aminotransferase (AST) and alanine transaminase (ALT) were significantly elevated in AC + WD9h groups (P < 0.05). Moreover, compared with that in NC group, the significant accumulation of reactive oxygen species (ROS) was observed in AC group and then reduced in combined stress groups (P < 0.05), with the highest level of malonaldehyde (MDA) in AC and AC + WD3h groups. Overall, the significant elevation of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC) was detected in AC + WD9h group (P < 0.05). Furthermore, the accumulative pathological impairment on hepatopancreas tissue revealed the cytoskeleton degradation. In addition, correlation analyses visualized the correlation between oxidative stress and biochemical response. This study not only deepens our understanding on the biochemical mechanism of shrimp mortality induced by combined stress, but also provides a potential strategy for improving the management of L. vannamei during live transport.

The efficient biomineralization and adsorption of cadmium (Cd2+) using secretory organo-biominerals (SOBs) produced by screened Alcaligenes faecalis K2.

Cadmium-contaminated wastewater has attracted increasing concerns due to its non-biodegradable properties and high toxicity. To explore eco-friendly and economically feasible strategies, the screened Alcaligenes faecalis K2 were employed for the biomineralization and recovery of Cd2+ from wastewater while producing considerable secretory organo-biominerals (SOBs) as bioadsorbents. At 75 mg/L Cd2+ exposure, 85.5% of Cd2+ was removed by K2, 43.0% of which was fixed in the granular SOBs. SOBs were convenient for separating from the solution. The adsorption capacity of granular sorbent made from SOBs was verified to be greater than 77.1 mg/g. Practically, 89.5% of 75 mg/L of Cd2+ could be stably removed while ereK2 continuously generated SOBs in a moving-bed biofilm reactor (MBBR). To sum up, the production of bioadsorbents can be achieved by K2, while removing Cd with live microorganisms, which was conducive to making full use of materials and improving Cd removal efficiency.

The algicidal efficacy and the mechanism of Enterobacter sp. EA-1 on Oscillatoria dominating in aquaculture system.

The global escalation and intensification of cyanobacterial blooms require powerful algaecides. This study investigated the algicidal efficacy and mechanism of EA-1 against Oscillatoria. Bacteria EA-1, identified as Enterobacter, was isolated with high algicidal activity against harmful cyanobacteria. Results showed that a complete removal of Oscillatoria was observed within 3 days with the initial Chl-a concentration of 1.74 mg/L. Physiological responses of Oscillatoria revealed that EA-1 induced severe lipid peroxidation and the ultimate decline of antioxidant enzyme activities. Moreover, the contents for both intracellular protein and carbohydrate of each algae cell increased first and then decreased. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) analysis clarified that the possible process of Oscillatoria lysis included the breach of cross wall, followed by the disruption of photosynthetic membrane and incipient nucleus, and the ultimate outflow of inclusion. Confocal laser scanning microscopy (CLSM) analysis illustrated the degradation process of incipient nucleus in Oscillatoria.

Insight into the roles of endogenous minerals in the activation of persulfate by graphitized biochar for tetracycline removal.

Owing to its environmental-friendliness, low-cost, and outstanding characteristics, biochar has been widely used for the catalytic degradation of various organic pollutants. In this study, a pre- and post-deashing graphitized biochar (DBC800 and PBC800-A) was prepared and compared with the pristine biochar (PBC800) to activate persulfate (PS) for tetracycline (TC) degradation. The influence of the natural endogenous mineral on the catalytic ability of biochar was investigated. Characterization results show that the inherent endogenous mineral in biochar not only acted as a natural pore-forming agent to promote the formation of the porous structure, but also facilitated the formation of edge defective structures, and altered the surface functional groups, as well as increased the carbonization and graphitization degree of biochar. The PBC800-A exhibited a much higher catalytic efficiency on PS activation and TC oxidative degradation with the reaction rate of 0.06055 min-1, 7.14 times as that of DBC800 (0.00861 min-1) and 4.63 times as that of PBC800 (0.00158 min-1). The endogenous minerals were conducive to the generation of free radicals and promoted the oxidative degradation of TC, which was mainly attributed to the improved carbon configuration. The post-deashing treatment was also found to significantly improve the electron transport efficiency of biochar by removing the residual ash, thereby promoting the generation of singlet oxygen. This study demonstrated that the natural minerals in biochar was beneficial for the degradation of TC, and more alternative natural minerals can be applied to co-pyrolysis with biochar for the remediation of refractory organic pollutants.

Strong association between HLA-B*1502 and carbamazepine-induced Stevens-Johnson syndrome and toxic epidermal necrolysis in mainland Han Chinese patients.

PURPOSE: The purpose of this study is to examine the association of HLA-B*1502 allele with CBZ-induced SJS/TEN in the mainland Han Chinese population. METHODS: HLA-B*1502 genotyping with sequence-specific primer polymerase chain reaction (PCR-SSP) and PCR-sequencing based typing (PCR-SBT) was performed on 17 CBZ-induced SJS/TEN patients, 21 CBZ-tolerant controls, and 185 healthy controls recruited during 2008-2010. RESULTS: HLA-B*1502 allele was present in 94.1% (16/17) of CBZ-SJS/TEN patients, 9.5% (2/21) of CBZ-tolerant patients, and 9.2% (17/185) of healthy controls. The risk of CBZ-induced SJS/TEN was significantly higher (P < 0.01) in the patients with HLA-B*1502. One CBZ-induced SJS patient tested negative for HLA-B*1502, and the test result showed HLA-B*3503/B*4601. CONCLUSIONS: We found a strong association between HLA-B*1502 and CBZ-induced SJS/TEN in the Han Chinese population from central and northern China. Combined with previous studies of the southern Han Chinese subpopulation, our results suggest that HLA-B*1502 is strongly associated with CBZ-induced SJS/TEN in the whole Han Chinese population.