Oxidative MnO2 Template Assisted Electrochemical Fabrication of Graphene/Polypyrrole Supercapacitor Electrodes.

Improving the morphological structure of active materials is a reliable strategy for the fabrication of high-performance supercapacitor electrodes. In this study, we introduce a feasible approach to constructing the graphene/polypyrrole (PPy) composite film implanted onto the current collector through a two-step electrochemical deposition method utilizing MnO2 as an intermediary template. The reduced graphene oxide (rGO) hydrogel film is first hydrothermally grown on a carbon cloth (CC) substrate to obtain a porous rGO@CC electrode on which MnO2 is electrodeposited. Then the as-prepared rGO/MnO2@CC electrode is subjected to the electrochemical polymerization of pyrrole, with MnO2 acting as an oxidizing template to facilitate the oxidative polymerization of pyrrole, ultimately yielding an rGO/PPy composite film on CC. The PPy synthesized via this methodology exhibits a distinctive interconnected structure, resulting in superior electrochemical performance compared with the electrode with PPy directly electrodeposited on rGO@CC. The optimized electrode achieves an impressive specific capacitance of 583.6 F g-1 at 1 A g-1 and retains 83% of its capacitance at 20 A g-1, with a capacitance loss of only 9.5% after 5000 charge-discharge cycles. The corresponding all-solid-state supercapacitor could provide a high energy density of 22.5 Wh kg-1 and a power density of 4.6 kW kg-1, with a capacitance retention of 82.7% after 5000 charge-discharge cycles. Furthermore, the device also demonstrates good flexibility performance upon bending at 90 and 180°. This work presents an innovative method for the preparation of carbon material/conducting polymer electrodes with specific structural characteristics and superior performance.

One-Step Fabrication of Integrated Graphene/Polypyrrole/Carbon Cloth Films for Supercapacitor Electrodes.

The facile and cost-effective preparation of supercapacitor electrodes is significant for the application of this kind of electrochemical energy-storing module. In this work, we designed a feasible strategy to fabricate a binary active material onto a current collector in one step. A colloidal mixture of graphene oxide and pyrrole layered on a carbon cloth could undergo a redox reaction through a mild hydrothermal process to yield a reduced graphene oxide/polypyrrole hydrogel film anchored onto the carbon cloth. The integrated electrode with the porous graphene/polypyrrole active material could be directly utilized as a freestanding working electrode for electrochemical measurements and the assembly of supercapacitor devices. The as-prepared electrode could achieve a high capacitance of 1221 mF cm-2 at 1 mA cm-2 (531 F g-1) with satisfactory cycling stability. The constructed symmetric supercapacitor with two optimal electrodes could provide an energy density of 70.4 µWh cm-2 (15.3 Wh kg-1). This work offers a feasible pathway toward the integration of graphene/conducting polymer composites as electrochemical electrodes.

HyPep: An Open-Source Software for Identification and Discovery of Neuropeptides Using Sequence Homology Search.

Neuropeptides are a class of endogenous peptides that have key regulatory roles in biochemical, physiological, and behavioral processes. Mass spectrometry analyses of neuropeptides often rely on protein informatics tools for database searching and peptide identification. As neuropeptide databases are typically experimentally built and comprised of short sequences with high sequence similarity to each other, we developed a novel database searching tool, HyPep, which utilizes sequence homology searching for peptide identification. HyPep aligns de novo sequenced peptides, generated through PEAKS software, with neuropeptide database sequences and identifies neuropeptides based on the alignment score. HyPep performance was optimized using LC-MS/MS measurements of peptide extracts from various Callinectes sapidus neuronal tissue types and compared with a commercial database searching software, PEAKS DB. HyPep identified more neuropeptides from each tissue type than PEAKS DB at 1% false discovery rate, and the false match rate from both programs was 2%. In addition to identification, this report describes how HyPep can aid in the discovery of novel neuropeptides.

Developing a sustainable process for the cleaner production of baker's yeast: An approach towards waste management by an integrated fermentation and membrane separation process.

Baker's yeast industries generate highly polluted effluents, especially the cell free broth (i.e., vinasse) characterized by high chemical oxygen demand, nitrogen, and salts. In this work, it was found that the residual by-products (i.e., ethanol and acetic acid) and salts in the vinasse severely inhibited the cell growth, which hindered the reuse of the vinasse for the production of Saccharomyces cerevisiae. Through optimizing a suitable control strategy, the productions of ethanol and acetic acid were eliminated. Then, a nanofiltration membrane (i.e., NF5) was preferred for preliminarily and simultaneously separating and concentrating valuable molecules (i.e., invertase, food grade proteins and pigments) in the vinasse, and the main fouling mechanism was cake layer formation. Subsequently, a reverse osmosis membrane (RO) was suitable to separate and concentrate salts in the NF5 permeate, where the membrane fouling was negligible. Finally, the RO permeate was successfully reused for the production of S. cerevisiae. In addition, without calculating the benefit from the recovery of the valuable molecules, the cost of the integrated process can be decreased by 59.8% compared with the sole triple effect evaporation. Meanwhile, the volume of the fresh water used in the fermentation process can be decreased by 68.8%. Thus, it is a sustainable process for the cleaner production of baker's yeast using the integrated fermentation and membrane separation process.

Effectively Converting Cane Molasses into 2,3-Butanediol Using Clostridiumljungdahlii by an Integrated Fermentation and Membrane Separation Process.

Firstly, 2,3-butanediol (2,3-BDO) is a chemical platform used in several applications. However, the pathogenic nature of its producers and the expensive feedstocks used limit its scale production. In this study, cane molasses was used for 2,3-BDO production by a nonpathogenic Clostridium ljungdahlii. It was found that cane molasses alone, without the addition of other ingredients, was favorable for use as the culture medium for 2,3-BDO production. Compared with the control (i.e., the modified DSMZ 879 medium), the differential genes are mainly involved in the pathways of carbohydrate metabolism, membrane transport, and amino acid metabolism in the case of the cane molasses alone. However, when cane molasses alone was used, cell growth was significantly inhibited by KCl in cane molasses. Similarly, a high concentration of sugars (i.e., above 35 g/L) can inhibit cell growth and 2,3-BDO production. More seriously, 2,3-BDO production was inhibited by itself. As a result, cane molasses alone with an initial 35 g/L total sugars was suitable for 2,3-BDO production in batch culture. Finally, an integrated fermentation and membrane separation process was developed to maintain high 2,3-BDO productivity of 0.46 g·L-1·h-1. Meanwhile, the varied fouling mechanism indicated that the fermentation properties changed significantly, especially for the cell properties. Therefore, the integrated fermentation and membrane separation process was favorable for 2,3-BDO production by C. ljungdahlii using cane molasses.

Fermentative Production of Fructo-Oligosaccharides Using Aureobasidium pullulans: Effect of Dissolved Oxygen Concentration and Fermentation Mode.

Fructo-oligosaccharides (FOS) are prebiotics with numerous health benefits. So far, the dissolved oxygen (DO) concentration control strategy for fermentative production of FOS is still unknown. In order to improve FOS production, the effects of DO concentration and fermentation mode on FOS using Aureobasidium pullulans were investigated in this study. The greatest FOS production (123.2 ± 6.2 g/L), with a yield of 61.6% ± 3.0% (g FOS/g sucrose), was obtained in batch culture under high DO concentration. Furthermore, repeated-batch culture revealed that enzyme production and FOS production were not closely associated with cell growth. By keeping the DO concentration above 5% in the repeated-batch culture, a maximum FOS concentration of 548.3 ± 37.4 g/L and yield of 68.6% ± 2.6% (g FOS/g sucrose) were obtained, which were 3.45% and 11.4% times higher than those obtained in the batch culture without DO control, respectively. Additionally, the ratios of 1-fructofuranosyl nystose (GF4) and 1,1,1,1-kestohexose (GF5) were 33.8% and 23.2%, respectively, in the product of repeated-batch culture, but these compounds were not detected in batch culture. Thus, it can be concluded that the DO concentration affects not only the yield of FOS but also the composition of FOS with different degrees of polymerization, which is the key factor in the fermentative production of FOS with a high polymerization degree.

A sustainable pH shift control strategy for efficient production of ß-poly(L-malic acid) with CaCO3 addition by Aureobasidium pullulans ipe-1.

ß-poly(L-malic acid) (PMLA) has attracted industrial interest for its potential applications in medicine and other industries. For a sustainable PMLA production, it requires replacing/reducing the CaCO3 usage, since the residual CaCO3 impeded the cells' utilization, and a large amount of commercially useless gypsum was accumulated. In this study, it was found that more glucose was converted into CO2 using soluble alkalis compared with CaCO3 usage. Moreover, since the high ion strength and respiration effect of soluble alkalis also inhibited PMLA production, they could not effectively replace CaCO3. Furthermore, comparing the fermentations with different neutralizers (soluble alkali vs. CaCO3), it was found that the differential genes are mainly involved in the pathway of starch and sucrose metabolism, pentose and glucuronate interconversions, histidine metabolism, ascorbate and aldarate metabolism, and phagosome. In detail, in the case with CaCO3, 562 genes were downregulated and 262 genes were upregulated, and especially, those genes involved in energy production and conversion were downregulated by 26.7%. Therefore, the irreplaceability of CaCO3 was caused by its effect on the PMLA metabolic pathway rather than its usage as neutralizer. Finally, a combined pH shift control strategy with CaCO3 addition was developed. After the fermentation, 64.8 g/L PMLA and 38.9 g/L biomass were obtained with undetectable CaCO3 and less CO2 emission. KEY POINTS: • The effect of CaCO3 on PMLA metabolic pathway resulted in its irreplaceability. • A pH shift control strategy with CaCO3 addition was developed. • Undetectable CaCO3 and less CO2 emission were detected with the new strategy. Graphical abstract.

Simultaneous decolorization and deproteinization of α,ω-dodecanedioic acid fermentation broth by integrated ultrafiltration and adsorption treatments.

α,ω-Dicarboxylic acids (DC) are versatile chemical intermediates with different chain length. For biosynthesis of DC, to obtain the highly pure product via crystallization, it is required to remove pigments and proteins in fermentation broth. However, a trade-off between decolorization/deproteinization ratio and DC recovery during the purification process was found, which impeded DC production by fermentation. When ultrafiltration (UF) was applied to treat α,ω-dodecanedioic acid (DC12) broth, 93.4% of DC12 recovery, 80.5% of decolorization ratio and 61.7% of deproteinization ratio were achieved by a PES 3 membrane. However, the membrane technology could not effectively retain the pigments or proteins with low molecular weight when a high DC12 permeation was required. Meanwhile, the selected activated charcoal or macroporous resins were not good adsorbents for the present system. Furthermore, an integrated process for decolorization and deproteinization was developed. After filtration with PES3 membrane, an activated charcoal was used to remove the small proteins and pigments in the UF permeate. As a result, 91.4% of DC12 recovery, 94.7% of decolorization ratio and 84.8% of deproteinization ratio were obtained by such two-stage strategy. These results would serve as a valuable guide for process design and practical operation in subsequent industrial application.

High-level productivity of α,ω-dodecanedioic acid with a newly isolated Candida viswanathii strain.

α,ω-Dicarboxylic acids (DC) are versatile chemical intermediates with different chain lengths, which are well-known as polymer building block. In this work, a new strain with high productivity of DC was isolated from oil-contaminated soil. Based on the morphology and phylogenetic analyses of the internal transcribed spacer sequences, it was characterized as Candida viswanathii. It was found that the contribution of carbon flux to the cell growth and DC production from n-dodecane could be regulated by the sucrose and yeast extract concentrations in the medium, and besides the broth pH, a suitable proportioning of sucrose and yeast extract was the key to achieve the optimal transition from cell growth phase to DC production phase. By optimizing culture conditions in a 7.5-L bioreactor, a higher DC productivity of 1.59 g·L-1 h-1 with a corresponding concentration of 181.6 g/L was obtained. After the purification of DC from the culture, the results from gas chromatography-mass spectrometry, infrared spectroscopy and 1H-NMR showed that α,ω-dodecanedioic acid (DC12) was the major product of C. viswanathii ipe-1 using pure n-dodecane as substrate. For the first time, we reported that a high productivity of DC12 could be produced by C. viswanathii.

High-definition de novo sequencing of crustacean hyperglycemic hormone (CHH)-family neuropeptides.

A complete understanding of the biological functions of large signaling peptides (>4 kDa) requires comprehensive characterization of their amino acid sequences and post-translational modifications, which presents significant analytical challenges. In the past decade, there has been great success with mass spectrometry-based de novo sequencing of small neuropeptides. However, these approaches are less applicable to larger neuropeptides because of the inefficient fragmentation of peptides larger than 4 kDa and their lower endogenous abundance. The conventional proteomics approach focuses on large-scale determination of protein identities via database searching, lacking the ability for in-depth elucidation of individual amino acid residues. Here, we present a multifaceted MS approach for identification and characterization of large crustacean hyperglycemic hormone (CHH)-family neuropeptides, a class of peptide hormones that play central roles in the regulation of many important physiological processes of crustaceans. Six crustacean CHH-family neuropeptides (8-9.5 kDa), including two novel peptides with extensive disulfide linkages and PTMs, were fully sequenced without reference to genomic databases. High-definition de novo sequencing was achieved by a combination of bottom-up, off-line top-down, and on-line top-down tandem MS methods. Statistical evaluation indicated that these methods provided complementary information for sequence interpretation and increased the local identification confidence of each amino acid. Further investigations by MALDI imaging MS mapped the spatial distribution and colocalization patterns of various CHH-family neuropeptides in the neuroendocrine organs, revealing that two CHH-subfamilies are involved in distinct signaling pathways.

Green process for isolation and purification of poly(ß-L-malic acid) from Aureobasidium spp. by an integrated ion exchange and membrane separation.

Poly (ß-L-malic acid) (PMLA) is a biopolymer used in food and medical fields. However, the industrial processes are susceptible to the pollution of CaSO4 waste and organic solvent owing to the heavy use of CaCO3 in fermentation process and organic solvents in isolation process. This study developed an organic solvent and CaSO4 -free process for the industrial-scale production of PMLA. Firstly, calcium ion was removed at pH 9.2 by pH adjustment with Na2CO3, and the generated CaCO3 was reused in the fermentation process. Then, the D296 resin was selected to isolate the PMLA from the Ca2+-free broth, where the adsorption data were both primely described by the Freundlich and Langmuir equation, while Freundlich model better fit the process than Langmuir equation, indicating that it was non-monolayer adsorption of PMLA on the resin. Meanwhile, a three-step gradient elution with phosphate buffer (i.e., 0.2 mol/L, pH 7.0) containing 0.1, 0.2 and 1 mol/L NaCl was developed to recover PMLA. Finally, a PES15 membrane was selected to recover the PMLA from the elution solution, which could be reused in the next cycle. As a result, the PMLA with a purity of 98.89 % was obtained with the developed green process. In the developed process, it removed the pollution of organic solvent and calcium waste for the biosynthesis of PMLA on an industrial scale, which also offers a sustainable and green route for the biosynthesis of other carboxylic acids.

Optimization of X-axis servo drive performance using PSO fuzzy control technique for double-axis dicing saw.

The dicing saw is a critical piece of equipment in IC processing, primarily used to cut wafers. Due to the high spindle speed, even small errors in the cutting process can result in wafer chipping or cracking. Therefore, the dicing saw requires a high degree of accuracy and stability. In this paper, the accuracy of the X-axis servo response was simulated using an Israeli ADT-8230 dual-axis abrasive wheel dicing saw. The study introduces a novel approach by using a fuzzy controller instead of the traditional position loop proportional integral (PI) controller. In addition, a two-input, two-output fuzzy rule is used for on-line correction of the position loop PI parameters. A heuristic algorithm is used to optimise the position loop fuzzy controller parameters. The quantization and proportionality factors are rectified using Particle Swarm Optimisation (PSO) algorithm and Genetic Algorithm (GA) respectively. By comparing the performance of the PSO fuzzy and GA fuzzy controllers, the optimal control method is derived. The proposed method is validated by simulation in the MATLAB/Simulink development environment using real ADT-8230 servo data. Experimental results show that the PSO-fuzzy structured controller reduces the position control error by 11.8%, improves the tracking performance by 26% and reduces the torque pulsation by 23%. Therefore, in future research, more advanced search algorithms should be further combined to improve the servo accuracy of the dicing saw.

L-Cys-Assisted Conversion of H2/CO2 to Biochemicals Using Clostridium ljungdahlii.

Carbon fixation and conversion based on Clostridium ljungdahlii have great potential for the sustainable production of biochemicals (i.e., 2,3-butanediol, acetic acid, and ethanol). Here, the effects of reducing agents on the production of biochemicals from H2/CO2 using C. ljungdahlii were studied. It was found that the element S and reducing power could significantly affect the production of biochemicals, and cysteine (Cys) was better than sodium sulfide for the production of biochemicals, especially for the production of 2,3-butanediol. Moreover, comparing to the control (i.e., without the addition of Cys), the gene expression profiles indicated that the fdh and adhE1 were significantly upregulated with the addition of Cys, which involved in pathways of the CO2 fixation and ethanol production. Therefore, the irreplaceability of Cys on the production of biochemicals was both caused by its utilization as a reducing agent and its effect on the metabolic pathway. Finally, compared to the control, the production of 2,3-butanediol was increased by 2.17 times under the addition of 1.7 g/L Cys.

Fractionation and characterization of poly(ß-L-malic acid) produced by Aureobasidium melanogenum ipe-1.

Poly (ß-L-malic acid) (PMLA) is attracting industrial interest for its potential application in medicine and other industries, whose functions primarily depend upon its molecular size and chemical structure. Up to now, the fractionation and characterization of PMLA produced by Aureobasidium spp. were still unclear. In this study, the product from A. melanogenum ipe-1 was effectively fractionated using 300 and 50 kDa membranes. During the filtration, the mechanisms of membrane fouling were illegible since the PMLA can both reject and permeate the membrane, while the main fouling mechanism varied between standard blocking and complete blocking during the diafiltration. After fractionation, 14.0, 8.4 and 77.6 % of the PMLAs with Mws of 75,134, 21,344 and 10,056 Da were distributed in the 300 kDa retentate after diafiltrating, 50 kDa retentate after diafiltrating, and the 50 kDa permeate, respectively. The Mw/Mns of the PMLAs were 4.12, 1.92, and 1.12 in the three fractions. Based on characteristic spectra of NMR, HPLC and FTIR, the product was not usual L-malic acid monomers, but glucose-terminated PMLA. The glucose was located at the terminal hydroxyl of PMLA. These results would serve as a valuable guide for process design and practical operation in subsequent industrial application.

Intensification of ß-poly(L: -malic acid) production by Aureobasidium pullulans ipe-1 in the late exponential growth phase.

ß-Poly(malic acid) (PMLA) has attracted industrial interest because this polyester can be used as a prodrug or for drug delivery systems. In PMLA production by Aureobasidium pullulans ipe-1, it was found that PLMA production was associated with cell growth in the early exponential growth phase and dissociated from cell growth in the late exponential growth phase. To enhance PMLA production in the late phase, different fermentation modes and strategies for controlling culture redox potential (CRP) were studied. The results showed that high concentrations of produced PMLA (above 40 g/l) not only inhibited PMLA production, but also was detrimental to cell growth. Moreover, when CRP increased from 57 to 100 mV in the late exponential growth phase, the lack of reducing power in the broth also decreased PMLA productivity. PMLA productivity could be enhanced by repeated-batch culture to maintain cell growth in the exponential growth phase, or by cell-recycle culture with membrane to remove the produced PMLA, or by maintaining CRP below 70 mV no matter which kind of fermentation mode was adopted. Repeated-batch culture afforded a high PMLA concentration (up to 63.2 g/l) with a productivity of 1.15 g l(-1) h(-1). Cell-recycle culture also confirmed that PMLA production by the strain ipe-1 was associated with cell growth.

Electrolytic stimulation in aid of poly(ß-L-malic acid) production by Aureobasidium melanogenum ipe-1.

Poly (ß-L-malic acid) (PMLA) is attracting industrial interest for its potential application in medicine and other industries. In this study, electrolytic stimulation assisted PMLA production was developed. Firstly, it was found that the pentavalent nitrogen source (i.e., NO3-) was more suitable for PMLA production. Secondly, a usual single-chamber bioelectric-fermentation system (BES) cannot improve PMLA production, which can only promote cell growth. Then, a new single-chamber BES with an external circulation was developed, where the PMLA metabolism was further intensified. Finally, the integration of NO3- addition and electrolytic stimulation mode (c) showed a positive synergy on the PMLA production. Compared to the case without NO3- addition and electrolytic stimulation, the PMLA production was increased by 22.9 % using the integrated process. Moreover, compared to the case without the electrolytic stimulation mode (c), it was revealed that the different genes involved in 12 metabolic subsystems using the integrated process, where 31 and 177 genes were up-regulated and down-regulated, respectively. The up-regulated genes were mainly participated in melanin metabolic process, catalase activity, and oxidoreductase activity. Hence, the integration of electrolytic stimulation represents a novel approach to improve PMLA production.

Discovery and characterization of the Crustacean hyperglycemic hormone precursor related peptides (CPRP) and orcokinin neuropeptides in the sinus glands of the blue crab Callinectes sapidus using multiple tandem mass spectrometry techniques.

The crustacean sinus gland (SG) is a well-defined neuroendocrine site that produces numerous hemolymph-borne agents including the most complex class of endocrine signaling molecules-neuropeptides. Via a multifaceted mass spectrometry (MS) approach, 70 neuropeptides were identified including orcokinins, orcomyotropin, crustacean hyperglycemic hormone (CHH) precursor-related peptides (CPRPs), red pigment concentrating hormone (RPCH), pigment dispersing hormone (PDH), proctolin, RFamides, RYamides, and HL/IGSL/IYRamide. Among them, 15 novel orcokinins, 9 novel CPRPs, 1 novel orcomyotropin, 1 novel Ork/Orcomyotropin-related peptide, and 1 novel PDH were de novo sequenced via collision induced dissociation (CID) from the SG of a model organism Callinectes sapidus. Electron transfer dissociation (ETD) was used for sequencing of intact CPRPs due to their large size and higher charge state. Capillary isoelectric focusing (CIEF) was employed for separation of members of the orcokinin family, which is one of the most abundant neuropeptide families observed in the SG. Collectively, our study represents the most complete characterization of neuropeptides in the SG and provides a foundation for future investigation of the physiological function of neuropeptides in the SG of C. sapidus.

Berberine on the Prevention and Management of Cardiometabolic Disease: Clinical Applications and Mechanisms of Action.

Berberine is an alkaloid from several medicinal plants originally used to treat diarrhea and dysentery as a traditional Chinese herbal medicine. In recent years, berberine has been discovered to exhibit a wide spectrum of biological activities in the treatment of diverse diseases ranging from cancer and neurological dysfunctions to metabolic disorders and heart diseases. This review article summarizes the clinical practice and laboratory exploration of berberine for the treatment of cardiometabolic and heart diseases, with a focus on the novel insights and recent advances of the underlying mechanisms recognized in the past decade. Berberine was found to display pleiotropic therapeutic effects against dyslipidemia, hyperglycemia, hypertension, arrhythmia, and heart failure. The mechanisms of berberine for the treatment of cardiometabolic disease involve combating inflammation and oxidative stress such as inhibiting proprotein convertase subtilisin/kexin 9 (PCSK9) activation, regulating electrical signals and ionic channels such as targeting human ether-a-go-go related gene (hERG) currents, promoting energy metabolism such as activating adenosine monophosphate-activated protein kinase (AMPK) signaling pathway, modifying gut microbiota to promote transforming of berberine into its intestine-absorbable form, and interacting with non-coding RNAs via targeting multiple signaling pathways such as AMPK, mechanistic target of rapamycin (mTOR), etc. Collectively, berberine appears to be safe and well-tolerated in clinical practice, especially for those who are intolerant to statins. Knowledge from this field may pave the way for future development of more effective pharmaceutical approaches for managing cardiometabolic risk factors and preventing heart diseases.

[Isolation and characterization of a new epsilon-poly-L-lysine-producing strain TUST-2].

OBJECTIVE: Epsilon-Poly-L-Lysine (epsilon-PL) is a natural amino acid homopolymer. The study aimed at isolating new epsilon-PL-producing strains. METHODS: epsilon-PL-producing strains were screened from the soil by using a new isolation approach which had three steps, (1) enrichment culturing epsilon-PL toleranting strains; (2) screening by improved Nishikawa's method; (3) selection of strains with higher epsilon-PL tolerant ability. RESULTS: A new epsilon-PL-producing strain TUST-2 was isolated from the soil collected from Hainan province, China. Chemotaxonomic and morphological characteristics of the isolate were typical of strain of the genus Streptomyces. The strain TUST-2 was found to belong to Streptomyces diastatochromogenes by comparative 16S rRNA gene sequence analysis. The purified fermentation product of the strain TUST-2 was confirmed as epsilon-PL by characteristic analysis, hydrolysate analysis, infrared spectrum, 1H NMR Spectrum, 13C NMR Spectrum, and MALDI-TOF-MS. CONCLUSION: On the basis of 16S rRNA gene sequence analysis and its morphological and physiological characteristics, epsilon-PL-producing strain TUST-2 is a new isolate of Streptomyces diastatochromogenes, named as Streptomyces diastatochromogenes TUST-2.

PRESnovo: Prescreening Prior to de novo Sequencing to Improve Accuracy and Sensitivity of Neuropeptide Identification.

Identification of peptides in species lacking fully sequenced genomes is challenging due to the lack of prior knowledge. De novo sequencing is the method of choice, but its performance is less than satisfactory due to algorithmic bias and interference in complex MS/MS spectra. The task becomes even more challenging for endogenous peptides that do not involve an enzymatic digestion step, such as neuropeptides. However, many neuropeptides possess common sequence motifs that are conserved across members of the same family. Taking advantage of this feature to improve de novo sequencing of neuropeptides, we have developed a method named PRESnovo (prescreening precursors prior to de novo sequencing) to predict the motif from a MS/MS spectrum. A neuropeptide sequence is broken into a motif with conserved amino acid residues and the remaining partial sequence. By searching against a predefined motif database constructed from known homologous sequences, PRESnovo assigns the most probable motif to each precursor via a sophisticated scoring function. Performance analysis was conducted with 15 neuropeptide standards, and 11 neuropeptides were correctly identified with PRESnovo compared to 1 identification by PEAKS only. We applied PRESnovo to assign motifs to peptide sequences in conjunction with PEAKS for assigning the rest of the peptide sequence in order to discover neuropeptides in tissue samples of green crab, C. maenas, and Jonah crab, C. borealis. Collectively, a large number of neuropeptides were identified, including 13 putative neuropeptides identified in green crab brain, 77 in Jonah crab brain, and 47 in Jonah crab sinus glands for the first time. This PRESnovo strategy greatly simplifies de novo sequencing and enhances the accuracy and sensitivity of neuropeptide identification when common motifs are present.