Macrophage polarization: an important role in inflammatory diseases.

Macrophages are crucial cells in the human body's innate immunity and are engaged in a variety of non-inflammatory reactions. Macrophages can develop into two kinds when stimulated by distinct internal environments: pro-inflammatory M1-like macrophages and anti-inflammatory M2-type macrophages. During inflammation, the two kinds of macrophages are activated alternatively, and maintaining a reasonably steady ratio is critical for maintaining homeostasis in vivo. M1 macrophages can induce inflammation, but M2 macrophages suppress it. The imbalance between the two kinds of macrophages will have a significant impact on the illness process. As a result, there are an increasing number of research being conducted on relieving or curing illnesses by altering the amount of macrophages. This review summarizes the role of macrophage polarization in various inflammatory diseases, including autoimmune diseases (RA, EAE, MS, AIH, IBD, CD), allergic diseases (allergic rhinitis, allergic dermatitis, allergic asthma), atherosclerosis, obesity and type 2 diabetes, metabolic homeostasis, and the compounds or drugs that have been discovered or applied to the treatment of these diseases by targeting macrophage polarization.

Global hotspots and trends in Myofascial Pain Syndrome research from 1956 to 2022: A bibliometric analysis.

Myofascial Pain Syndrome (MPS) is a prevalent disease, and the related literature research has been increasing in recent years. However, there is a lack of scientific and comprehensive bibliometric analyses in the MPS research field. This study aimed to summarize and visualize the literature distribution laws, research hotspots and development trends in MPS based on bibliometric methods. Relevant literature on MPS research from 1956 to 2022 was retrieved from the Web of Science Core Collection database. Quantitative and visual analyses of the collected literature were performed using Microsoft Office 2021, Bibliometrics, VOSviewer, and CiteSpace. A total of 1099 papers were included, and the number of papers in this research field is generally upward. The USA has the most publications (270), and Univ Sao Paulo is the institution with the most publications (31). Hong CZ and Calvo-Lobo C have the same number of publications and are the authors with the most publications (20), and Simons DG is the author with the most co-citations (1078). Journal of Musculoskeletal Pain is the journal with the most publications (61), and Pain is the journal with the most co-cited papers (2598) and the highest impact factor (7.926). Lidocaine injection versus dry needling to myofascial trigger point. The importance of the local twitch response is the reference with the highest number of co-citations (136). The top 5 keywords in this period are myofascial pain syndrome (571), trigger points (218), pain (97), myofascial pain (92), and myofascial trigger point (80). The keywords of recent bursts are dry needling (2016-2022), efficacy (2020-2022), validity (2020-2022), temporomandibular joint disorder (2020-2022), and orofacial pain (2020-2022). This study summarizes and visualizes the evolution, research hotspots, and future trends of the global MPS domain from 1956 to 2022. It is helpful for scholars to understand the general situation of MPS research quickly and provide a reference for clinical decision-making and future research directions.

High-level expression and purification of a molluskan endoglucanase from Ampullaria crossean in Pichia pastoris.

EG27I is an endogenous glucanase belonging to glycoside hydrolase family (GHF) 45 from the mollusk Ampullaria crossean. In this study, the mature EG27I peptide gene fused to the HFBII secretion signal of Trichoderma reesei was expressed under the GAP promoter of Pichia pastoris in SMD1163 strain. A bioactive EG27I with a molecular weight of 27 kDa was successfully expressed and secreted into our culture medium. The respective final OD600 and hydrolytic activity were 333 and 1.28 U/mL when high-cell-density fermentation of the recombinant P. pastoris was performed in a 7.5 L fermenter through a fed-batch strategy for 132 h. The recombinant protein concentration of the fermentation supernatant was 47.7 mg/L. EG27I was consecutively purified from the fermentation supernatant through ultrafiltration, cation exchange, and hydrophobic interaction. The specific activity of the recombinant EG27I was 26.8 U/mg, and the optimal pH and temperature of the enzyme were 5 and 50 °C, respectively. The half-life of the enzyme activity at 100 °C could reach 40 min. The N-terminal amino acid sequence analysis of the purified recombinant protein confirmed that the amino terminal sequence was consistent with the natural structure. The high quantity and purity of the EG27I provide a basis for future structural and functional studies.

Action modes of recombinant endocellulase, EGA, and its domains on cotton fabrics.

OBJECTIVES: The action modes of an endocellulase, EGA, and its domains (CD9 and CBM3) during enzymatic treatment of cotton fabrics were investigated. RESULTS: EGA, CD9 and CBM3 had the binding capacity to cellulose substrates, of which the filter paper was the substrate with the strongest binding capacity. Analyses of scanning electronic microscopy indicated that EGA and its catalytic domain CD9 etched the surface of cotton fabrics and broke the fibers of long chains. On the other hand, the binding domain CBM3 only resulted in swelling of cotton fibers. Both EGA and its catalytic domain CD9 had minimal effect on the weight loss of cotton fabrics, whereas the effect of EGA and CD9 on the degree of polymerization and breaking strength was significant. After 12 h enzymatic action, the values of weight loss ratio for EGA and CD9 were 2.07 and 2.21 %, respectively, meanwhile the reductions in fabric strength were 27.04 % for EGA and 17.23 % for CD9. CONCLUSIONS: In contrast to the action of EGA and CD9, CBM3 showed no significant changes in terms of the weight loss ratio, degree of polymerization, and fabric strength.

Identification of a novel vaccine candidate by immunogenic screening of Vibrio parahaemolyticus outer membrane proteins.

Vibrio parahaemolyticus is an important halophilous pathogen that can cause not only a broad range of disease in aquatic animals but also serious seafood-borne illness in humans as a result of the consumption of seafood. To avoid the use of antibiotics, it is critical to identify protective antigens for developing highly effective vaccines against this pathogen. Outer membrane proteins (OMPs) have been suggested as potential vaccine candidates for conferring protection against infection. In this study, we identified novel immunogenic OMPs using an immune assay with serum antibodies from mice infected by V. parahaemolyticus combined with mass spectrometry analysis. Nine OMPs were identified to be immunogenic proteins, and four of these identified proteins with relatively low abundance in OMP profiles, LptD, VP0802, VP1243 and VP0966, were determined to have immunogenicity for the first time. One OMP of interest, VP0802, is highly conserved among major Vibrio species and was proposed to adopt a ß-barrel conformation and to be a member of the OprD protein family by bioinformatic analysis. The immunogenicity and protective efficacy of VP0802 were further evaluated by bacterial challenge postimmunization in a mouse model. VP0802 was confirmed to be highly immunogenic and to offer strong protection against V. parahaemolyticus infection, with an RPS of at least 66.7. Efficient clearance of bacteria from the blood of vaccinated mice was also observed. Moreover, upregulation of VP0802 expression was found after bacteria were exposed to fresh sera. These data, taken together, suggest that VP0802 is a promising candidate for the development of a subunit vaccine to prevent V. parahaemolyticus infection.

Involvement of RbAp48 in erythroid differentiation of murine erythroleukemia cells induced by sodium butyrate.

Normal mammalian terminal erythroid differentiation is a precisely regulated process during which the progenitor cells execute particular programs to form a mature erythrocytic phenotype. In the present study, it was found that RbAp48, a histone-binding protein associated with retinoblastoma protein, was upregulated during terminal erythroid maturation in vivo and in vitro. This indicated that RbAp48, at least in part, participated in the regulation of murine erythropoiesis. Following sodium butyrate (SB) induction, murine erythroleukemia (MEL) cells began to re-enter erythroid differentiation and the ratio of differentiated cells reached ~80% at 72 h. The erythroid maturation-related mRNA expression of α-globin, ß-globin and glycophorin A (GPA) was increased markedly, which indicated that SB induced MEL differentiation. During MEL differentiation, the RbAp48 level showed a 1.5-fold increase at 72 h, and the globin transcription factor (GATA)-1 level was also upregulated in the early stage of differentiation. By contrast, the c-Myc level was gradually downregulated in MEL differentiation. Using an immunofluorescence assay, the results of the study directly showed that the average fluorescence intensity of RbAp48 in each cell reached an almost 1.7-fold increase at 72 and 96 h. This was consistent with the western blot results of RbAp48 during MEL differentiation. In addition, reduced expression of RbAp48 by RNA inference decreased SB-induced MEL differentiation by ~20%, indicating that a high level of RbAp48 was essential for MEL differentiation. Taken together, these results established a functional link between RbAp48 and erythroid differentiation.

Systematic analysis of the lysine acetylome in Vibrio parahemolyticus.

Lysine acetylation of proteins is a major post-translational modification that plays an important regulatory role in almost every aspect of cells, both eukaryotes and prokaryotes. Vibrio parahemolyticus, a model marine bacterium, is a worldwide cause of bacterial seafood-borne illness. Here, we conducted the first lysine acetylome in this bacterium through a combination of highly sensitive immune-affinity purification and high-resolution LC-MS/MS. Overall, we identified 1413 lysine acetylation sites in 656 proteins, which account for 13.6% of the total proteins in the cells; this is the highest ratio of acetyl proteins that has so far been identified in bacteria. The bioinformatics analysis of the acetylome showed that the acetylated proteins are involved in a wide range of cellular functions and exhibit diverse subcellular localizations. More specifically, proteins related to protein biosynthesis and carbon metabolism are the preferential targets of lysine acetylation. Moreover, two types of acetylation motifs, a lysine or arginine at the +4/+5 positions and a tyrosine, histidine, or phenylalanine at the +1/+2 positions, were revealed from the analysis of the acetylome. Additionally, protein interaction network analysis demonstrates that a wide range of interactions are modulated by protein acetylation. This study provides a significant beginning for the in-depth exploration of the physiological role of lysine acetylation in V. parahemolyticus.

Different regulatory pathways are involved in the proliferative inhibition of two types of leukemia cell lines induced by paclitaxel.

Paclitaxel, one of the broadest-spectrum anticancer agents, is currently being used in the treatment of patients with solid tumors. In the present study, we compared the effect of paclitaxel on two types of leukemia cells. Our results showed that paclitaxel could inhibit the proliferation of MEL and K562 cells in a dose- and time-dependent manner. The mechanism of proliferative inhibition in K562 cells treated by paclitaxel was related to the cell cycle arrest in the G2/M phase, as well as the induction of apoptosis. By contrast, MEL cells treated by paclitaxel showed significant characteristics of necrosis, which indicated that the mode of cell death induced by paclitaxel in these two types of leukemia cells differed. Advances in research of the cell cycle, apoptosis and necrosis will extend our understanding of the mechanisms of paclitaxel-induced cell death, particularly in leukemia cells. Further elucidation of the mechanisms of necrosis in MEL cells may expedite the development of improved paclitaxel-based regimens for cancer therapy.

Outer membrane protein OmpW of Escherichia coli is required for resistance to phagocytosis.

Eight-stranded ß-barrel outer membrane proteins can confer bacterial virulence via resistance to host innate defenses. This resistance function of OmpW, which was recently identified as an eight-stranded ß-barrel protein, was investigated in this study. Our results demonstrated that upregulation of OmpW correlated with increased bacterial survival during phagocytosis. Bacterial mutants harboring a deletion of ompW exhibited a significantly increased phagocytosis rate. Both observations suggest that the OmpW protein protects bacteria against host phagocytosis. In addition, expression of ompW is regulated by iron, which implies that the resistance provided by OmpW may be an important factor in iron-related infectious diseases. Furthermore, OmpW has been identified as a protective antigen that protects mice against bacterial infection and is therefore a promising target for vaccine development against infectious diseases.

Novel cytotoxic exhibition mode of antimicrobial peptide anoplin in MEL cells, the cell line of murine Friend leukemia virus-induced leukemic cells.

Anoplin is a recently discovered antimicrobial peptide (AMP) isolated from the venom sac of the spider wasp Anoplius samariensis, and it is one of the shortest α-helical AMP found naturally to date consisting of only ten amino acids. Previous results showed that anoplin exhibits potent antimicrobial activity but little hemolytic activity. In this study, we synthesized anoplin, studied its cytotoxicity in Friend virus-induced leukemia cells [murine erythroleukemia (MEL) cells], and proposed its possible mechanism. Our results showed that anoplin could inhibit the proliferation of MEL cells in a dose-dependent and time-dependent manner via disrupting the integrity of cell membrane, which indicated that anoplin exerts its cytotoxicity efficacy. In addition, the cell cycle distribution of MEL cells was arrested in the G0/G1 phase significantly. However, anoplin could not induce obvious apoptosis in MEL cells, as well as anoplin could not induce visible changes on morphology and quantity in the bone marrow cells isolated from normal mice. All of these results indicate that anoplin, as generally believed, is a selective AMP, a value characteristic in the design of safe therapeutic agents. The cytotoxicity of anoplin on MEL cells was mainly attributable to the plasma membrane perturbation and also to the intracellular events such as the arrest of cell cycle. Although this is an initial study that explored the activity of anoplin in vitro rather than in vivo, with the increasing resistance of conventional chemotherapy, there is no doubt that anoplin has desirable feature to be developed as a novel and selective anticancer agent.

Study on the distribution sites and the molecular mechanism of analgesia after intracerebroventricular injection of rat/mouse hemokinin-1 in mice.

Hemokinin-1 is a peptide encoded by Pptc, which belongs to the family of mammalian tachykinins. Our previous results showed that rat/mouse hemokinin-1 (r/m HK-1) produced striking analgesia after intracerebroventricular (i.c.v.) injection in mice, and the analgesia could be blocked by the NK1 receptor antagonist and the opioid receptor antagonist, respectively. However, the precise distribution sites and the molecular mechanism involved in the analgesic effect after i.c.v. administration of r/m HK-1 are needed to be further investigated deeply. Using the fluorescence labeling method, our present results directly showed that r/m HK-1 peptides were mainly distributed at the ventricular walls and several juxta-ventricular structures for the first time. Our results showed that the mRNA expressions of NK1 receptor, PPT-A, PPT-C, KOR, PDYN, DOR and PENK were not changed markedly, as well as the protein expression of NK1 receptor was hardly changed. However, both the transcripts and proteins of MOR and POMC were up-regulated significantly, indicating that the analgesic effect induced by i.c.v. administration of r/m HK-1 is related to the activation of NK1 receptor first, then it is related to the release of endogenous proopiomelanocortin, as well as the increased expression level of µ opioid receptor. These results should facilitate further the analysis of the analgesia of r/m HK-1 in the central nerval system in acute pain and may open novel pharmacological interventions.

[Construction of ompW knock-out mutants of Escherichia coli to increase sensitivity to neomycinsulphate and ampicillin].

OBJECTIVE: To investigate the contribution of an outer membrane protein OmpW to tolerance neomycinsulphate and ampicillin of Escherichia coli K12. METHODS: The ompW knock-out mutant (deltaompW) of E. coli K12 was generated using lambda-Red recombination system. Then the minimal inhibitory concentration (MIC) and the survival rates under 1/2 MIC of neomycinsulphate or ampicillin of deltaompW and E. coli K12 were determined respectively. RESULTS: The deltaompW was successfully obtained through confirmation of PCR analysis at the gene level and Western blot analysis at the protein level. The MIC of neomycinsulphate of deltaompW is 1.7 microg/mL. The value is much lower than that of E. coli K12, which is 8.0 microg/mL. Difference of survival rates under 1/2 MIC of neomycinsulphate of deltaompW and E. coli K12 was also observed, and their survival rates are 39% and 98% , respectively. The MIC of ampicillin of deltaompW is 3.3 microg/mL. The value is also lower than that of E. coli K12 (16.0 microg/mL). The survival rates under 1/2 MIC ampicillin of deltaompW and E. coli K12 are 30.3% and 70.38%, respectively. CONCLUSION: The AompW is much more sensitive to neomycinsulphate and ampicillin than its parent strain. The result indicated that OmpW played crucial role in bacteria resistance of drug.

X-ray crystallographic characterization of new soluble endohedral fullerenes utilizing the popular C82 bucky cage. Isolation and structural characterization of Sm@C3v(7)-C82, Sm@C(s)(6)-C82, and Sm@C2(5)-C82.

Three isomers of Sm@C(82) that are soluble in organic solvents were obtained from the carbon soot produced by vaporization of hollow carbon rods doped with Sm(2)O(3)/graphite powder in an electric arc. These isomers were numbered as Sm@C(82)(I), Sm@C(82)(II), and Sm@C(82)(III) in order of their elution times from HPLC chromatography on a Buckyprep column with toluene as the eluent. The identities of isomers, Sm@C(82)(I) as Sm@C(s)(6)-C(82), Sm@C(82)(II) as Sm@C(3v)(7)-C(82), and Sm@C(82)(III) as Sm@C(2)(5)-C(82), were determined by single-crystal X-ray diffraction on cocrystals formed with Ni(octaethylporphyrin). For endohedral fullerenes like La@C(82), which have three electrons transferred to the cage to produce the M(3+)@(C(82))(3-) electronic distribution, generally only two soluble isomers (e.g., La@C(2v)(9)-C(82) (major) and La@C(s)(6)-C(82) (minor)) are observed. In contrast, with samarium, which generates the M(2+)@(C(82))(2-) electronic distribution, five soluble isomers of Sm@C(82) have been detected, three in this study, the other two in two related prior studies. The structures of the four Sm@C(82) isomers that are currently established are Sm@C(2)(5)-C(82), Sm@C(s)(6)-C(82), Sm@C(3v)(7)-C(82), and Sm@C(2v)(9)-C(82). All of these isomers obey the isolated pentagon rule (IPR) and are sequentially interconvertable through Stone-Wales transformations.

Comparative proteomic analysis of colon cancer cell HCT-15 in response to all-trans retinoic acid treatment.

Colon cancer is one of the most common malignances. In vitro and in vivo study show that retinoic acids inhibit a wide variety of cancer cells but the molecular mechanism of their anti-tumor effects are not yet fully understood. Alltrans retinoic acid (ATRA), an isomer of retinoic acid, can inhibit the proliferation of HCT-15 human colon cancer cell line. A proteomic analysis was performed using HCT-15 treated with ATRA to further elucidate the retinoic acid signaling pathway and its anti-tumor effect mechanism. MTT results showed that the growth of HCT-15 cells were significantly inhibited by ATRA. The alkaline phosphatase activity assay showed that ATRA failed to induce the differentiation of HCT-15. The DNA ladder detection showed that ATRA induced apoptosis in HCT-15. Two-dimensional gel electrophoresis coupled with MALDI-TOF/TOF mass spectrometry identified 13 differentially expressed proteins in HCT-15 cells after all-trans retinoic acid treatment. Among the identified differentially expressed proteins, there were four scaffold proteins (YWHAE, SFN, YWHAB, and YWHAZ), two ubiquitin modification related proteins (ISG-15 and UBE2N), two translational initiation factors (EIF1AX and EIF3K), two cytoskeleton related proteins (EZRI and CNN3), two proteinmodification related proteins (TXNDC17 and PIMT), and one enzyme related to phospholipid metabolism (PSP). Both EZRI and UBE2N were rendered to western-blot validation and the results were consistent with the two-dimension electrophoresis analysis. In this study, the differentially expressed proteins in HCT-15 treated by ATRA were identified, which will assist the further elucidation of the anti-tumor mechanism of retinoic acids.

Using Markov model to improve word normalization algorithm for biological sequence comparison.

There are two crucial problems with statistical measures for sequence comparison: overlapping structures and background information of words in biological sequences. Word normalization in improved composition vector method took into account these problems and achieved better performance in evolutionary analysis. The word normalization is desirable, but not sufficient, because it assumes that the four bases A, C, T, and G occur randomly with equal chance. This paper proposed an improved word normalization which uses Markov model to estimate exact k-word distribution according to observed biological sequence and thus has the ability to adjust the background information of the k-word frequencies in biological sequences. The improved word normalization was tested with three experiments and compared with the existing word normalization. The experiment results confirm that the improved word normalization using Markov model to estimate the exact k-word distribution in biological sequences is more efficient.

Integrating overlapping structures and background information of words significantly improves biological sequence comparison.

Word-based models have achieved promising results in sequence comparison. However, as the important statistical properties of words in biological sequence, how to use the overlapping structures and background information of the words to improve sequence comparison is still a problem. This paper proposed a new statistical method that integrates the overlapping structures and the background information of the words in biological sequences. To assess the effectiveness of this integration for sequence comparison, two sets of evaluation experiments were taken to test the proposed model. The first one, performed via receiver operating curve analysis, is the application of proposed method in discrimination between functionally related regulatory sequences and unrelated sequences, intron and exon. The second experiment is to evaluate the performance of the proposed method with f-measure for clustering Hepatitis E virus genotypes. It was demonstrated that the proposed method integrating the overlapping structures and the background information of words significantly improves biological sequence comparison and outperforms the existing models.

Site-directed mutagenesis of aromatic residues in the carbohydrate-binding module of Bacillus endoglucanase EGA decreases enzyme thermostability.

The endoglucanase, EGA, from Bacillus sp. AC-1 comprises a glycosyl hydrolase family-9 catalytic module (CM9) and a family-3 carbohydrate-binding module (CBM3). Seven aromatic residues were subjected to site-directed mutagenesis in both CBM3 and EGA to investigate their roles in enzyme thermostability. The complexes generated by mixing CBMY527G, CBMW532A, or CBMF592G with CM9 each lost their activities after 15 min at 45°C, while the wild-type complex retained >70% activity after 2 h. The mutants EGAY527G, EGAW532A, and EGAF592G showed little activity after 15 min at 60°C, whereas EGA remained 70% active after 2 h. Thus the residues Tyr(527), Trp(532), and Phe(592) contribute not only to CBM3-mediated stability of CM9 but also to EGA thermostability suggesting that hydrophobic interaction between the two modules, independent of covalent linkages, is important for enzyme thermostability.

Expression and characterization of full-length Ampullaria crossean endoglucanase EG65s and their two functional modules.

Three endoglucanase cDNAs, eg65a, eg65b, and eg65c, were cloned from the mollusk Ampullaria crossean in previous work. To characterize the full-length enzymes as well as their individual functional modules via heterologous expression analysis, the three full-length putative endoglucanases (rEG65a, rEG65b, and rEG65c) and the corresponding catalytic modules (EG65a-CM, EG65b-CM, and EG65c-CM) were expressed in Pichia pastoris GS115, and the three corresponding carbohydrate-binding modules (EG65a-CBM, EG65b-CBM, and EG65c-CBM) were expressed in Escherichia coli BL21 (DE3). The properties of recombinant rEG65b, EG65a-CM, EG65b-CM, and EG65c-CM were characterized. Binding assays of CBMs with insoluble polysaccharides indicated that both EG65b-CBM and EG65c-CBM bound to phosphoric-acid swollen cellulose (PASC), Avicel, and oat-spelt xylan, while EG65a-CBM did not. The relative equilibrium constants (K(r)) of EG65b-CBM and EG65c-CBM were determined by absorption isotherm measurements. In this study, the CBMs of animal cellulases were expressed and characterized for the first time.

Numerical characteristics of word frequencies and their application to dissimilarity measure for sequence comparison.

Sequence comparison is one of the major tasks in bioinformatics, which can be used to study structural and functional conservation, as well as evolutionary relations among the sequences. Numerous dissimilarity measures achieve promising results in sequence comparison, but challenges remain. This paper studied numerical characteristics of word frequencies and proposed a novel dissimilarity measure for sequence comparison. Instead of using the word frequencies directly, the proposed measure considers both the word frequencies and overlapping structures of words. To verify the effectiveness of the proposed measure, we tested it with two experiments and further compared it with alignment-based and alignment-free measures. The results demonstrate that the proposed measure extracting more information on the overlapping structures of the words improves the efficiency of sequence comparison.

Purification and characterization of a novel endo-ß-1,4-glucanases , AfEG22, from the giant snail, Achatina fulica frussac.

In this study, we confirmed that at least three endo-ß-1,4-glucanases existed in the digestive juice of the giant snail, Achatina fulica ferussac, by Congo red staining assay. One of these enzymes, a novel endo-ß-1,4-glucanase (AfEG22), was purified 29.5-fold by gel filtration, anion exchange, and hydrophobic interaction chromatography. The carboxymethyl cellulose (CMC) hydrolytic activity of the purified enzyme was 12.3 U/mg protein. The molecular mass of AfEG22 was 22081 Da determined by MALDI-TOF. N-terminal amino acid sequencing revealed a sequence of EQRCTNQGGILKYYNT, which did not have significant homology with any proteins in BLAST database. The optimal pH and temperature for hydrolytic activity toward CMC were pH 4.0 and 50°C, respectively. AfEG22 was stable between pH 3.0 and pH 12.0 when incubated at 4°C for 3 h or at 37°C for 1 h. The enzyme remained more than 80% activity between pH 4.5 and pH 7.0 after incubation at 50°C for 1 h. AfEG22 possessed excellent thermostability as more than 70% activity was remained after incubation at 60°C for 3 h. Substrate specific analysis revealed that AfEG22 was a typical endo-ß-1,4-glucanase. This is the first time to report a novel endo-ß-1,4-glucanase with high stability from the digestive juice of A. fulica.