Synthesis of Alkene Atropisomers with Multiple Stereogenic Elements via Catalytic Asymmetric Rearrangement of 3-Indolylmethanols.

Catalytic enantioselective preparation of alkene atropisomers with multiple stereogenic elements and discovery of their applications have become significant but challenging issues in the scientific community due to the unique structures of this class of atropisomers. We herein report the first catalytic atroposelective preparation of cyclopentenyl[b]indoles, a new kind of alkene atropisomers, with stereogenic point and axial chirality via an unusual rearrangement reaction of 3-indolylmethanols under asymmetric organocatalysis. Notably, this novel type of alkene atropisomers have promising applications in developing chiral ligands or organocatalysts, discovering antitumor drug candidates and fluorescence imaging materials. Moreover, the theoretical calculations have elucidated the possible reaction mechanism and the non-covalent interactions to control the enantioselectivity. This approach offers a new synthetic strategy for alkene atropisomers with multiple stereogenic elements, and represents the first catalytic enantioselective rearrangement reaction of 3-indolylmethanols, which will advance the chemistry of atropisomers and chiral indole chemistry.

Bioflocculation characteristics of bound extracellular polymers substances from Pseudomonas sp. XD-3 and behavior of polysaccharides.

This study aimed to investigate the bioflocculation characteristics of bound extracellular polymers substances (B-EPS), which were extracted from Pseudomonas sp. XD-3. The flocculation efficiency of B-EPS achieved about 80%- 95% with an initial pH of 4-7, kaolin concentrations of 3-7 g L-1, temperature of 25-100 â„ƒ and B-EPS dosage of 9-105 mg L-1. The bioflocculation process of B-EPS conformed to pseudo-second-order kinetic mode, suggesting that the bioflocculation belonged to chemical adsorption process. Enzymatic hydrolysis experiments demonstrated that both polysaccharides and proteins were active components for bioflocculation. The polysaccharides were irregular aggregates with rough and porous surfaces and contained hydroxyl and carboxyl groups, which helped to promote bridging effect. Ribose, glucose and galactose were the main monosaccharides of polysaccharides. The molecular weight of the polysaccharides was relatively small, but the relatively loose configuration exposed more ion bridging sites, thus promoting the bioflocculation. Optimizing the ingredients of culture medium and culture time for B-EPS were effective strategies to increase the yield of flocculation active components. When the conditions were 10% of 2 g L-1 KH2PO4 + 5 g L-1 K2HPO4, 0.05% of Tween-80, citrate as carbon source and 32-48 h of culture time, both proteins and polysaccharides in B-EPS were significantly improved. This study gives an in-deep understanding on the flocculation characteristics of a novel bioflocculant from Pseudomonas sp. XD-3, which is conducive to the widespread application of bioflocculation.

Improvement in nitrogen removal and changes in community structure in a sequencing batch reactor bioaugmented with P. stutzeri strain XL-2.

The aim of this work was to study the bioaugmentation of P. stutzeri strain XL-2 in activated sludge to improve nitrogn removal from wastewater with the guide of growth kinetics. When 4250 mg/L COD and 80 mg/L NH4+-N were applied, the TN removal efficiency in a bioaugmented sequencing batch reactor (SBRXL) achieved 95%, while that in the control reactor (SBRC) without strain XL-2 was only 84% (P < 0.05). The microbial community analysis demonstrated that strain XL-2 was successfully bioaugmented in SBRXL, and increasing influent COD concentration promoted its abundance. Influent COD concentration played a dominant role in affecting community structure, while the bioaugmentation of strain XL-2 had much less impact on the community structure. Combined with principal coordinates analysis, redundancy analysis and FAPROTAX, the improvement of TN removal was mainly achieved by the bioaugmentation of strain XL-2, which played a major role in promoting aerobic denitrification.

Underlying mechanisms of ANAMMOX bacteria adaptation to salinity stress.

Dealing with nitrogen-rich saline wastewater produced by industries remains challenging because of the inhibition of functional microorganisms by high salinity. The underlying mechanisms of anaerobic ammonium-oxidizing bacteria (AnAOB) exposed to salinity stress should be studied to investigate the potential of anaerobic ammonium oxidation (ANAMMOX) for applications in such wastewater. In this study, the total DNA from granular sludge was extracted from an expanded granular sludge bed (EGSB) reactor operated at 0, 15 and 30 g/L salinity and subjected to high-throughput sequencing. The nitrogen removal performance in the reactor could be maintained from 86.2 to 88.0% at less than 30 g/L salinity level. The microbial diversity in the reactor under saline conditions was lower than that under the salt-free condition. Three genera of AnAOB were detected in the reactor, and Candidatus Kuenenia was the most abundant. The predictive functional profiling based on the Clusters of Orthologous Groups of proteins (COGs) database showed that the inhibition of AnAOB under saline conditions was mainly characterised by the weakening of energy metabolism and intracellular repair. AnAOB might adapt to salinity stress by increasing their rigidity and intracellular osmotic pressure. The predictive functional profiling based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database revealed that the inhibition of AnAOB was mainly manifested by the weakening of intracellular carbohydrate and lipid metabolism, the blockage of intracellular energy supply and the reduction of membrane transport capacity. AnAOB might adapt to salinity stress by strengthening wall/membrane synthesis, essential cofactors (porphyrins) and energy productivity, enhancing intracellular material transformation and gene repair and changing its structure and group behaviour. The stability of the nitrogen removal performance could be maintained via the adaptation of AnAOB to salinity and their increased abundance.

Bioaugmentation with A. faecalis strain NR for achieving simultaneous nitrogen and organic carbon removal in a biofilm reactor.

The dynamics model of Alcaligenes faecalis NR was combined with the activated sludge model No. 1 to guide how to make the bioaugmentation of strain NR successful. Model studies show that conventional heterotrophic bacteria in activated sludge always outcompete strain NR. The competition between strain NR and Nitrosomonas, a typical ammonium-oxidizing bacterium (AOB), mainly depends on COD concentration and maximum growth rate of Nitrosomonas. 2000mg/L of COD ensures that strain NR is always able to outcompete AOB. A biofilm reactor was developed to avoid a quick decrease in influent substrates. Approximately 94.2% of TN and 93.6% of COD were removed in the bioaugmented biofilm reactor, showing much better performance than an identical biofilm reactor without strain NR inoculation. A long-term experiment showed that strain NR successfully proliferated in the bioaugmented reactor. The abundance variation of strain NR mainly depended on influent COD concentrations, which was consistent with the model results.

Extracellular protein analysis of activated sludge and their functions in wastewater treatment plant by shotgun proteomics.

In this work, proteins in extracellular polymeric substances extracted from anaerobic, anoxic and aerobic sludges of wastewater treatment plant (WWTP) were analyzed to probe their origins and functions. Extracellular proteins in WWTP sludges were identified using shotgun proteomics, and 130, 108 and 114 proteins in anaerobic, anoxic and aerobic samples were classified, respectively. Most proteins originated from cell and cell part, and their most major molecular functions were catalytic activity and binding activity. The results exhibited that the main roles of extracellular proteins in activated sludges were multivalence cations and organic molecules binding, as well as in catalysis and degradation. The catalytic activity proteins were more widespread in anaerobic sludge compared with those in anoxic and aerobic sludges. The structure difference between anaerobic and aerobic sludges could be associated with their catalytic activities proteins. The results also put forward a relation between the macro characteristics of activated sludges and micro functions of extracellular proteins in biological wastewater treatment process.

A Novel Bio-carrier Fabricated Using 3D Printing Technique for Wastewater Treatment.

The structure of bio-carriers is one of the key operational characteristics of a biofilm reactor. The goal of this study is to develop a series of novel fullerene-type bio-carriers using the three-dimensional printing (3DP) technique. 3DP can fabricate bio-carriers with more specialized structures compared with traditional fabrication processes. In this research, three types of fullerene-type bio-carriers were fabricated using the 3DP technique and then compared with bio-carrier K3 (from AnoxKaldnes) in the areas of physicochemical properties and biofilm growth. Images acquired by 3D profiling and SEM indicated that the surface roughness of the 3DP bio-carrier was greater than that of K3. Furthermore, contact angle data indicated that the 3DP bio-carriers were more hydrophilic than K3. The biofilm on the 3DP bio-carriers exhibited higher microbial activity and stronger adhesion ability. These findings were attributed to excellent mass transfer of the substrate (and oxygen) between the vapour-liquid-solid tri-phase system and to the surface characteristics. It is concluded that the novel 3DP fullerene-type bio-carriers are ideal carriers for biofilm adherence and growth.

Microbial communities, extracellular proteomics and polysaccharides: A comparative investigation on biofilm and suspended sludge.

Biofilm and suspended sludge (S-sludge) floc exhibit distinct physicochemical properties and process performances in an integrated fixed-film and suspended growth sequencing batch reactor. However, the mechanisms of governing these differences between the two aggregates were unknown. Current work evaluated the diversity of morphologies, microbial communities, extracellular proteins and polysaccharides between the biofilm and S-sludge. Contrast to biofilm, the denitrification was much more extensive performed in S-sludge. Furthermore, many microbial cells in the biofilm acted as the backbone of aggregates and maintained the structure stability. An extracellular protein observed only in the biofilm can promote the cell adhesion. In contrast, more extracellular proteins related to catalytic activity in the S-sludge could decrease the compactness of floc. In addition, the monosaccharide compositions from the two aggregates were various. These results could elucidate how the diversities of architecture and biochemical process between the two aggregates occurred.

Start-up of a combined anaerobic/partial nitritation/anammox process for high-salt mustard wastewater treatment.

To treat high salinity wastewater from the mustard pickling industry, a combined anaerobic, partial nitritation (PN), and anammox process was employed using three connected reactors: an anaerobic sequencing batch biofilm reactor (ASBBR) for anaerobic treatment, a sequencing batch reactor (SBR) for PN, and an upflow anaerobic sludge blanket (UASB) for anammox. The start-up of the three individual reactors was investigated. Results showed that each reactor started up successfully, notwithstanding the stepwise increase of influent salinity to about 16.1 g NaCl/L. In the ASBBR, 89.7 % of chemical oxygen demand in the influent was removed and organic nitrogen was converted to ammonium (NH4 (+)-N). The SBR performed well with NO3 (-)-N concentration of 4.9 mg/L and ratio of NO2 (-)-N to NH4 (+)-N at the range of 1.0 to 1.3 in the effluent, which favored the anammox process. After the start-up of the UASB, the anammox process also showed stability and efficiency with a high total nitrogen removal efficiency of 86.2 % under high salinity of 12.0 g NaCl/L and nitrogen loading rate of 258 mg/(L · day).

Composition of EPS fractions from suspended sludge and biofilm and their roles in microbial cell aggregation.

The adhesion and aggregation properties of microbial cell are closely related to extracellular polymeric substances (EPS). In this work, the composition and physicochemical characteristics of EPS in biofilm and suspended sludge (S-sludge) were determined to evaluate their roles in microbial cell aggregation. Raman spectroscopy and three-dimensional fluorescence spectra have been employed to reveal each EPS fraction in different composition. The flocculating capacity of each EPS fraction in the S-sludge shows extraordinary activity, comparing its counterpart in biofilm. Microbial cell surfaces present high hydrophobicity and increased zeta potentials upon EPS extraction. In addition, the respective contribution of EPS to cell aggregating was elucidated. The contribution of combined SEPS and LB-EPS was 23% for S-sludge sample, whereas that was negligible for biofilm sample. The contribution of LB-EPS and TB-EPS were 16% and 30% for S-sludge sample, and -6% and negligible for biofilm sample, respectively. Therefore, EPS promoted the S-sludge cells to aggregate, while in contrast, they showed a negligible or negative effect on the biofilm cells aggregating.

Adsorption behavior of tightly bound extracellular polymeric substances on model organic surfaces under different pH and cations with surface plasmon resonance.

Tightly bound extracellular polymeric substances (TB-EPS) play a substantial role on microbial aggregates, which can promote microbial cells to aggregate and adhere onto the carrier in bioreactor. However, the attachment and adsorption of TB-EPS on different surfaces were awaited to be elucidated. In this study, four self-assembled monolayers (SAMs) carrying methyl (CH3-SAM), amino (NH2-SAM), hydroxyl (OH-SAM), and carboxyl (COOH-SAM) terminal groups were prepared to model different surfaces. TB-EPS adsorption on these surfaces under different pH conditions and additional cations were investigated using surface plasmon resonance. The adsorption of TB-EPS dramatically decreased with the decreasing pH values. CH3-SAM surface achieved the maximum adsorption at the same condition. Na(+) promoted the TB-EPS adsorbed on COOH-SAM surface. The Ca(2+)-mediated complexes were attracted by COOH-SAM and repelled by NH2-SAM, respectively. The adsorptions of TB-EPS on the four SAM surfaces were significantly increased by adding Fe(3+). These results demonstrated that the TB-EPS adsorption on the organic surfaces were dependent on the pH and cation of solution.

Increased inflammatory factors activity in model rats with experimental autoimmune prostatitis.

Male rats were immunized with prostate tissue homogenate supernate (PTHS) of male rats with complete Freund's adjuvant (CFA) intra dermal in the multiple points and simultaneously immunized with 0.5 ml Pertussis-Diphtheria-Tetanus (PDT) vaccine intra peritonea on 0 and 30th day. At the 45th day after first immunization, animals were sacrificed and a series of examinations such as HE stain, assay of TNF-alpha by ELISA and assay of inducible nitric oxide synthase (iNOS) mRNA by in-situ hybridization (ISH) were taken. We observed that there was a remarkable up-regulation of TNF-alpha expression in the high dosage model group. The results of macropathology, histopathology and iNOS ISH also revealed the same tendency. This experimental procedure is effective to induce chronic abacterial prostatitis (CAP).

[Morphological and molecular biological peculiarities of the experimental autoimmune prostatitis rat model].

OBJECTIVE: To observe the morphological and molecular biological peculiarities of the experimental autoimmune prostatitis (EAP) rat model made by SC purified prostate protein twice with immune adjuvant. METHODS: Male rats were intradermally immunized with a saline extract of male rat prostate glands (RPG) in Freund's complete adjuvant (FCA) and Pertussis-Diphtheria-Tetanus vaccine 0.5 ml i.p. at the 0 and 30th day, and the concentrations of the extract were respectively 5 mg/ml, 10 mg/ml and 15 mg/ml. At the 45th day, the rats were sacrificed and the morphological and molecular biological changes of the prostate specimens were observed to determine the effective concentration of RPG for a successful model. RESULTS: The expression of inflammation genes such as TNF-alpha, IL-1beta, IL-2 and iNOS obviously increased in the high-dosage model group; LM, EM and in situ hybridization revealed appearant chronic inflammation response, but this was not the case in the other two dosage groups. CONCLUSION: 15 mg/ml RPG mixed with FCA (1:1) 1.0 ml SC with Pertussis-Diphtheria-Tetanus vaccine 0.5 ml i.p. was an effective dosage for the successful model in our experiment.