[Primary cystic echinococcosis in the left femur: a case report]

This article reported a case with primary cystic echinococcosis in the left femur.

Role of Intrinsic Factors of Polyimides in Glass Transition Temperature: An Atomistic Investigation

Polyimides (PIs) are in high demand in the field of active matrix organic light-emitting diode displays because of their excellent heat resistance, chemical stability, and mechanical properties. However, the most critical key to their application is to further enhance their glass transition temperature (T_g), which directly affects the processing temperature of thin-film transistors on the PI films. Therefore, it is of great importance to study the factors that have an influence on the T_g of PIs. To accomplish this goal, PIs derived from pyromellitic acid dianhydride and three sets of isomeric imidazole-based diamines were investigated. The investigation, by computational methods, was to clarify the effect of intrinsic factors associated with the molecular structure of the PIs on their T_g and to construct a structure-T_g relationship for these PIs. For each model system, all-atom molecular dynamics simulations were used to identify and distinguish the effects of chain rigidity, fractional free volume (FFV), cohesive energy density, hydrogen-bonding interactions, and charge-transfer complex interactions on T_g. The results showed that the physical property, chain rigidity, has a direct impact on T_g regardless of the polymer backbone structure. A linear correlation between the increase of FFV and the decrease of T_g was not established due to the existence of hydrogen-bonding interactions, but the tendency was maintained. Furthermore, the formation of hydrogen bonds was found to have an indirect relationship with T_g. That is, the increase of intrachain hydrogen bonds would lead to a decrease in chain rigidity and consequently reduce the T_g value.

Te-Li Exchange Reaction of Tellurophene-Containing π-Conjugated Polymer as Potential Synthetic Tool for Functional π-Conjugated Polymers

On the basis of the facts that tellurophene-containing π-conjugated polymers are obtainable from organotitanium polymers and that the tellurium atoms in the tellurophene derivatives can be transformed into lithium atoms, the synthesis of reactive lithiated polymer precursor and its transformations into some functionalized π-conjugated polymers are described. A regioregular organometallic polymer having 1,4-dilithio-1,3-butadiene and 9,9-dioctylfluorene-2,7-diyl units is generated by the reaction of a tellurophene-containing polymer having the number-average molecular weight (M_n ) and molecular weight distribution (M_w /M_n ) of 5890 and 1.9, respectively, with n-butyllithium (2.4 equiv.) at -78 °C to -60 °C for 3 h. The lithiated polymer thus prepared is subjected to reactions with electrophiles to produce functionalized π-conjugated polymers. For example, a π-conjugated polymer possessing 1,4-bis(tri-n-butylstannyl)-1,3-butadiene-1,4-diyl unit is obtained in 67% yield by the reaction with tri-n-butyltin chloride (2.4 equiv.) at -60 °C to ambient temperature for 12 h in tetrahydrofuran, whose M_n and M_w /M_n are estimated as 7320 and 2.5, respectively, by size exclusion chromatography. The absorption maximum and onset of the obtained polymer are observed at 380 and 465 nm, respectively, in the UV-vis spectrum, from which the optical band gap of the polymer is estimated as 2.67 eV.

N-Glycosylation Plays an Essential and Species-Specific Role in Anti-Infection Function of Milk Proteins Using Listeria monocytogenes as Model Pathogen

The released milk N-glycome has been found to possess antipathogenic activity. Natively, they are covalently linked onto proteins. Whether the conjugated N-glycans still have antipathogenic properties and how the glycosylation influences the antipathogenic activity of proteins remain unclear. Herein, we compared the quantitative differences of milk protein N-glycosylation and the antilisterial differences of native milk proteins, released N-glycan pools, and deglycosylated proteins between human and bovine milk. N-glycosylation exhibited to be quantitatively species-specific. The entire growth inhibitory activity and the majority of the antiadhesive activity against Listeria monocytogenes of milk whey proteins, although not as high as the released N-glycans, are attributed to N-glycosylation. Moreover, all N-glycan-bearing samples from human milk showed better growth inhibitory activities than those from bovine milk. Generally, N-glycosylation significantly contributes to the antilisterial function of milk proteins and to the functional differences between species. This gives novel insights into the role of these glycoconjugates in nature.

Somatic symptoms and their association with anxiety and depression in Chinese patients with cardiac neurosis

Objective

We sought to investigate somatic symptoms detected by the Somatic Self-rating Scale and to evaluate whether they were associated with the psychological symptoms of anxiety and depression in patients with cardiac neurosis.

Methods

A total of 180 patients with cardiac neurosis at the Third Xiangya Hospital, Changsha, China, were surveyed from January 2017 to July 2018. Participants completed a general information questionnaire, the Somatic Self-rating Scale, the Patient Health Questionnaire-9 and the Generalized Anxiety Disorder Scale-7.

Results

The mean (±standard deviation) somatic symptom score in patients with cardiac neurosis was 40.83 ± 7.12. The most severe symptoms were cardiovascular symptoms, fatigue and muscle soreness. A total of 90 patients (46.4%) had anxiety and 80 (50.0%) had depression. Multiple stepwise regression analysis showed that somatic symptoms in patients with cardiac neurosis were associated with both anxiety and depression.

Conclusion

Somatic symptoms in patients with cardiac neurosis were associated with both anxiety and depression. Therefore, it is important to provide effective emotional interventions to promote patient rehabilitation.

Mir-138-5p acts as a tumor suppressor by targeting pyruvate dehydrogenase kinase 1 in human retinoblastoma

OBJECTIVE

MicroRNAs have caught more attention for their role in tumor progression. Retinoblastoma (RB) is one of these ordinary malignant tumors. This study aims to identify whether mir-138-5p can regulate the development of RB, and find out its potential mechanism.

MATERIALS AND METHODS

Mir-138-5p expression in RB cells was monitored by RT-qPCR. Besides, the role of mir-138-5p in RB development was explored through function experiments in vitro. The potential mechanism was further explored by RT-qPCR, luciferase assay, and Western blot assay.

RESULTS

In our investigation, mir-138-5p was lower-expressed in RB cells than that in retinal pigment epithelial cells. Moreover, overexpression of mir-138-5p repressed cell viability, migration and invasion, and induced apoptosis of RB cells, while downregulated mir-138-5p increased cell viability, migration and invasion, and reduced apoptosis of RB cells. Furthermore, pyruvate dehydrogenase kinase 1 (PDK1) could be downregulated via overexpression of mir-138-5p, while PDK1 was upregulated via knockdown of mir-138-5p.

CONCLUSIONS

Our results suggested that mir-138-5p could repress the development of RB via suppressing PDK1, which may offer a new vision for interpreting the mechanism of RB tumorigenesis.

A novel redox/pH dual-responsive and hyaluronic acid-decorated multifunctional magnetic complex micelle for targeted gambogic acid delivery for the treatment of triple negative breast cancer

Gambogic acid (GA) is a naturally derived potent anticancer agent with extremely poor biocompatibility. In the present study, a novel of redox/pH dual-responsive multifunctional magnetic complex micelle (sPEG/HA/CSO-SS-Hex/Fe₃O₄/GA), which consisted of a reducible hexadecanol-modified chitosan oligosaccharide polymer micelle (CSO-SS-Hex) coated with hyaluronic acid (HA) and DCA grafted sheddable PEG-PLL (sPEG) copolymers and loaded with gambogic acid (GA) and Fe₃O₄ nanoparticles were developed for parenteral delivery for the treatment of triple negative breast cancer (TNBC). The ex vivo study showed that the sPEG shielded cationic HA/CSO-SS-Hex/Fe₃O₄/GA core at physiological pH but quickly shed off to re-expose the core due to its charge reversible property. The sPEG/HA/CSO-SS-Hex/Fe₃O₄/GA micelles effectively facilitated tumor-targeted GA delivery by HA, which is a targeting ligand for CD44 receptor of TNBC cells, meanwhile increase GA uptake at the acidic condition but diminished the drug uptake at neutral pH. The in vitro cellular uptake study and in vivo biodistribution and antitumor activity of the formulations were determined, all results showed that the complex micelle enhanced TNBC tumor cellular uptake and fast drug release due to the combined effect of magnet targeting, CD44 receptor-mediated internalization and redox/pH dual-responsive drug release. Hence, tumor-targeted delivery of GA with redox/pH dual-responsive multifunctional magnetic complex micelle sPEG/HA/CSO-SS-Hex/Fe₃O₄/GA might have potential implications for the chemotherapy of TNBC.

A new HPLC-UV derivatization approach for the determination of potential genotoxic benzyl halides in drug substances

Benzyl halides, widely used as alkylation reagents in drug synthesis, are potential genotoxic impurities (PGTIs) required to be controlled at trace levels. However, the existing analytical methods for benzyl halides often suffer from matrix interferences or low derivatization efficiency of benzyl chlorides. In this paper, a simple derivatization HPLC-UV method was developed for the analysis of these residual trace benzyl halides in drug substances. 1-(4-Nitrophenyl) piperazine (4-NPP) was selected as a new derivatization reagent because it shifted well the benzyl halides derivatives away to the near visible range (392 nm), which could minimize the matrix interferences from the drug substances and related impurities. Meanwhile, potassium iodide (KI) was used to convert the mixed benzyl halides into benzyl iodides before derivatization. The derivatization parameters were also optimized using the design of experiments (DoE) for achieving the best reaction efficiency. The results showed that the new approach had high specificity and sensitivity, and the LOQs were 7–9 μg g⁻¹ relative to 5 mg mL⁻¹ antipyrine and 17.5–22.5 μg g⁻¹ relative to 2 mg mL⁻¹ oroxylin A. The method is a valuable alternative for the determination of residual benzyl halides in the drug substances.

Benzyl halides, widely used as alkylation reagents in drug synthesis, are potential genotoxic impurities (PGTIs) required to be controlled at trace levels.

Targeted deep sequencing from multiple sources demonstrates increased NOTCH1 alterations in lung cancer patient plasma

Introduction

Targeted therapies are based on specific gene alterations. Various specimen types have been used to determine gene alterations, however, no systemic comparisons have yet been made. Herein, we assessed alterations in selected cancer‐associated genes across varying sample sites in lung cancer patients.

Materials and Methods

Targeted deep sequencing for 48 tumor‐related genes was applied to 153 samples from 55 lung cancer patients obtained from six sources: Formalin‐fixed paraffin‐embedded (FFPE) tumor tissues, pleural effusion supernatant (PES) and pleural effusion cell sediments (PEC), white blood cells (WBCs), oral epithelial cells (OECs), and plasma.

Results

Mutations were detected in 96% (53/55) of the patients and in 83% (40/48) of the selected genes. Each sample type exhibited a characteristic mutational pattern. As anticipated, TP53 was the most affected sequence (54.5% patients), however this was followed by NOTCH1 (36%, across all sample types). EGFR was altered in patient samples at a frequency of 32.7% and KRAS 10.9%. This high EGFR/ low KRAS frequency is in accordance with other TCGA cohorts of Asian origin but differs from the Caucasian population where KRAS is the more dominant mutation. Additionally, 66% (31/47) of PEC samples had copy number variants (CNVs) in at least one gene. Unlike the concurrent loss and gain in most genes, herein NOTCH1 loss was identified in 21% patients, with no gain observed. Based on the relative prevalence of mutations and CNVs, we divided lung cancer patients into SNV‐dominated, CNV‐dominated, and codominated groups.

Conclusions

Our results confirm previous reports that EGFR mutations are more prevalent than KRAS in Chinese lung cancer patients. NOTCH1 gene alterations are more common than previously reported and reveals a role of NOTCH1 modifications in tumor metastasis. Furthermore, genetic material from malignant pleural effusion cell sediments may be a noninvasive manner to identify CNV and participate in treatment decisions.

MicroRNA-98-5p prevents bone regeneration by targeting high mobility group AT-Hook 2

MicroRNAs (mRNAs or miRs) serve an important role in the regulation of gene expression. In the present study, the role of miR-98-5p in bone regeneration was determined. Three osteoblast cell models were established, including primary human stem cells (BMMSC), mouse BMMSC's and MC3T3-E1 cells. miR-98-5p expression was determined using reverse transcription-quantitative (RT-q)PCR. Osteoblast markers, including alkaline phosphatase, runt related transcription factor 2 and transcription factor Sp7, were determined using RT-qPCR and western blot analysis, respectively. Alkaline phosphatase activity was determined in the present study and cell proliferation and apoptosis assays were performed. Furthermore, an association between miR-98-5p and high mobility group AT-Hook 2 (HMGA2) was revealed. This association was determined using TargetScan and a dual luciferase reporter assay. The current study demonstrated that miR-98-5p was downregulated during osteogenic differentiation and further demonstrated that HMGA2 may be a direct target of miR-98-5p. The results also demonstrated that miR-98-5p upregulation significantly inhibited the osteogenic differentiation of MC3T3-E1 cells, an effect that was reversed by an increased HMGA2 expression. Additionally, the results revealed that miR-98-5p upregulation inhibited MC3T3-E1 cell viability and induced cell apoptosis and these effects were eliminated by HMGA2 overexpression. In conclusion, miR-98-5p may prevent bone regeneration through inhibiting osteogenic differentiation and osteoblast growth by targeting HMGA2.

Genetically Encoding Photocaged Quinone Methide to Multitarget Protein Residues Covalently in Vivo

Genetically introducing covalent bonds into proteins in vivo with residue specificity is affording innovative ways for protein research and engineering, yet latent bioreactive unnatural amino acids (Uaas) genetically encoded to date react with one to few natural residues only, limiting the variety of proteins and the scope of applications amenable to this technology. Here we report the genetic encoding of (2 R)-2-amino-3-fluoro-3-(4-((2-nitrobenzyl)oxy) phenyl) propanoic acid (FnbY) in Escherichia coli and mammalian cells. Upon photoactivation, FnbY generated a reactive quinone methide (QM), which selectively reacted with nine natural amino acid residues placed in proximity in proteins directly in live cells. In addition to Cys, Lys, His, and Tyr, photoactivated FnbY also reacted with Trp, Met, Arg, Asn, and Gln, which are inaccessible with existing latent bioreactive Uaas. FnbY thus dramatically expanded the number of residues for covalent targeting in vivo. QM has longer half-life than the intermediates of conventional photo-cross-linking Uaas, and FnbY exhibited cross-linking efficiency higher than p-azido-phenylalanine. The photoactivatable and multitargeting reactivity of FnbY with selectivity toward nucleophilic residues will be valuable for addressing diverse proteins and broadening the scope of applications through exploiting covalent bonding in vivo for chemical biology, biotherapeutics, and protein engineering.

[Clinical study of cervical necrotizing fasciitis accompanied with descending necrotizing mediastinitis treated with cervical double parallel incision combined with mediastinoscope or thoracoscope]

Objective: To summarize the experience of applying cervical double parallel incision combined with mediastinoscope or thoracoscope in the treatment of cervical necrotizing fasciitis (CNF) accompanied with descending necrotizing mediastinitis (DNM), so as to provide a reference for clinical practice. Methods: The clinical data of six patients with CNF accompanied with DNM who were admitted to the Department of Stomatology and the Department of Otolaryngology Head and Neck Surgery, The First People's Hospital of Changzhou from September 2014 to September 2018 were retrospectively analyzed. All of the six patients were confirmed by CT of neck and chest, among whom there were two males and four females aged from 48 to 73. Three patients were treated with cervical double parallel incision combined with mediastinoscope to be combined with cervical and thoracic drainage under general anesthesia while the other three with cervical double parallel incision combined with thoracoscope to be combined cervical and thoracic drainage under general anesthesia. The CT of neck and chest as well as infectious indicators including hematology, C-reactive protein (CRP) and procalcitonin (PCT) were reexamined during the postoperative period. Results: The cervical and thoracic combined drainage was unobstructed in all of the six patients, no secondary surgery was performed, and the infectious indicators gradually decreased. All patients had off-bed activities on the first day after the operation, were all cured and discharged after an average of 21 days (16 to 36 days) in hospital and followed up for an average of 18 months (4 to 30 months) after the operation. None of them experienced infection relapse, and they were all satisfied with the appearance of the cervical incision. Conclusions: Cervical double parallel incision combined with mediastinoscope or thoracoscope for the treatment of CNF accompanied with DNM has the advantages of complete drainage, small trauma, excellent efficacy and aesthetic operative area, thus being deserved to be clinically popularized.

Genetically Introducing Biochemically Reactive Amino Acids Dehydroalanine and Dehydrobutyrine in Proteins

Expansion of the genetic code with unnatural amino acids (Uaas) has significantly increased the chemical space available to proteins for exploitation. Due to the inherent limitation of translational machinery and the required compatibility with biological settings, function groups introduced via Uaas to date are restricted to chemically inert, bioorthogonal, or latent bioreactive groups. To break this barrier, here we report a new strategy enabling the specific incorporation of biochemically reactive amino acids into proteins. A latent bioreactive amino acid is genetically encoded at a position proximal to the target natural amino acid; they react via proximity-enabled reactivity, selectively converting the latter into a reactive residue in situ. Using this Genetically Encoded Chemical COnversion (GECCO) strategy and harnessing the sulfur-fluoride exchange (SuFEx) reaction between fluorosulfate-l-tyrosine and serine or threonine, we site-specifically generated the reactive dehydroalanine and dehydrobutyrine into proteins. GECCO works both inter- and intramolecularly, and is compatible with various proteins. We further labeled the resultant dehydroalanine-containing protein with thiol-saccharide to generate glycoprotein mimetics. GECCO represents a new solution for selectively introducing biochemically reactive amino acids into proteins and is expected to open new avenues for exploiting chemistry in live systems for biological research and engineering.

Oral vs intravenous tranexamic acid in total-knee arthroplasty and total hip arthroplasty: A systematic review and meta-analysis

BACKGROUND

This study aimed to compare the efficacy and safety of oral tranexamic acid (TXA) with intravenous (IV) TXA in reducing perioperative blood loss in total-knee arthroplasty (TKA) and total-hip arthroplasty (THA).

METHODS

PubMed, Web of Science, Embase, and Cochrane Library were fully searched for relevant studies. Studies comparing the efficacy and safety of oral TXA with IV TXA in TKA and THA were included in this research. Odds ratio (OR) or risk difference (RD) was applied to compare dichotomous variables, while mean difference (MD) was used to compare continues variables.

RESULTS

A total of 7 studies (5 randomized controlled trials and 2 retrospective studies) were included into this study. As for patients undergoing TKA or THA, there were no obvious differences between oral TXA group and IV TXA group in hemoglobin (Hb) drop (MD = 0.06, 95% confidence interval [CI] = -0.01 to 0.13, P = .09), transfusion rate (OR = 0.78, 95% CI = 0.54-1.13, P = .19), total blood loss (MD = 16.31, 95% CI = -69.85 to 102.46, P = .71), total Hb loss (MD = 5.18, 95% CI = -12.65 to 23.02, P = .57), length of hospital stay (MD = -0.06, 95% CI = -0.30 to 0.18, P = .63), drain out (MD = 21.04, 95% CI = -15.81 to 57.88, P = .26), incidence of deep vein deep vein thrombosis (RD = 0.00, 95% CI = -0.01 to 0.01, P = .82) or pulmonary embolism (RD = 0.00, 95% CI = -0.01 to 0.01, P = .91). The sample size of this study was small and several included studies were with relatively low quality.

CONCLUSION

Oral TXA is equivalent to IV TXA in reducing perioperative blood loss and should be recommended in TKA and THA. More high-quality studies are needed to elucidate this issue.

Rapidly Visualizing the Membrane Affinity of Gene Vectors Using Polydiacetylene-Based Allochroic Vesicles

The high-throughput screening of chemically active substances has aroused widespread interest in recent years. The screening of drug carriers is usually ignored, although they interact directly with physiological barriers and target cells, and they determine the fate and efficacy of drugs in vivo. In this work, a series of polydiacetylene (PDA) vesicles (ca. 550 nm) that simulate the cell membrane are constructed to detect the membrane affinity of gene vectors. The surface potentials of vesicles are adjusted by changing the phospholipid composition using different charged compounds. All vesicles show the rapid color changes upon the addition of gene vectors by the naked eye within <5 min. The optimized 1,2-dimyristoyl- sn-glycero-3-phosphocholine (DMPC)-PDA vesicles display the most sensitive discoloration response to the commercially available gene vectors, including Lipofectamine 2000, Entranster-H4000, and polyethylenimine. The logarithm of transfection efficiency for green fluorescent protein plasmid (pGFP) mediated by these three vectors in L02 and HepG2 cells demonstrate an excellent linear correlation with the logarithm of membrane affinity (log K_b) of the gene vectors detected by DMPC-PDA vesicles. This rapid visualization method not only allows the in vitro membrane affinity prediction of gene vectors that greatly contributes to the gene transfection efficiency, but also offers a universal strategy for the potential high-throughput screening of various carrier materials featuring high cell affinity.

Improved predictive models for acute kidney injury with IDEA: Intraoperative Data Embedded Analytics

Background

Acute kidney injury (AKI) is a common complication after surgery that is associated with increased morbidity and mortality. The majority of existing perioperative AKI risk prediction models are limited in their generalizability and do not fully utilize intraoperative physiological time-series data. Thus, there is a need for intelligent, accurate, and robust systems to leverage new information as it becomes available to predict the risk of developing postoperative AKI.

Methods

A retrospective single-center cohort of 2,911 adults who underwent surgery at the University of Florida Health between 2000 and 2010 was utilized for this study. Machine learning and statistical analysis techniques were used to develop perioperative models to predict the risk of developing AKI during the first three days after surgery, first seven days after surgery, and overall (after surgery during the index hospitalization). The improvement in risk prediction was examined by incorporating intraoperative physiological time-series variables. Our proposed model enriched a preoperative model that produced a probabilistic AKI risk score by integrating intraoperative statistical features through a machine learning stacking approach inside a random forest classifier. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC), accuracy, and Net Reclassification Improvement (NRI).

Results

The predictive performance of the proposed model is better than the preoperative data only model. The proposed model had an AUC of 0.86 (accuracy of 0.78) for the seven-day AKI outcome, while the preoperative model had an AUC of 0.84 (accuracy of 0.76). Furthermore, by integrating intraoperative features, the algorithm was able to reclassify 40% of the false negative patients from the preoperative model. The NRI for each outcome was AKI at three days (8%), seven days (7%), and overall (4%).

Conclusions

Postoperative AKI prediction was improved with high sensitivity and specificity through a machine learning approach that dynamically incorporated intraoperative data.

cPLA2a correlates with metastasis and poor prognosis of osteosarcoma by facilitating epithelial-mesenchymal transition

BACKGROUND

Osteosarcoma (OS) patients with metastasis have very dismal prognoses, and lack effective target therapies. Overexpression of cytosolic phospholipase A2 (cPLA₂) has been shown to promote progression in several types of cancers, but its functions in OS have not been investigated.

MATERIALS AND METHODS

In our study, the expression of cPLA₂a was detected with immunohistochemistry in 102 cases of OS. The clinical significance of cPLA₂a was evaluated by analyzing its correlation with clinicopathological factors. The prognostic significance of cPLA₂a was estimated by univariate and multivariate analysis. The oncogenic functions of cPLA₂a on cell proliferation and invasion were investigated by MTT assay and tranwell assay respectively. Western blotting was applied to detect the markers of epithelial-mesenchymal transition (EMT) after silencing cPLA₂a expression or inhibiting its activity by a specific antagonist.

RESULTS

In our study, high expression of cPLA₂a was significantly associated with metastasis and advanced Enneking stage. High cPLA₂a expression was significantly associated with poor prognosis and it was an independent prognostic biomarker of OS. By silencing cPLA₂a or inhibiting its activity by a specific antagonist, we demonstrated that cPLA₂a promoted cell invasion of OS cells via inducing the EMT process.

CONCLUSIONS

High cPLA₂a expression was an independent prognostic biomarker of OS, and cPLA₂a could promote OS cell invasion via inducing the EMT process, indicating that cPLA₂a was an independent prognostic biomarker and may be an effective drug target for OS.

Characterization of Stackebrandtia nassauensis GH 20 Beta-Hexosaminidase, a Versatile Biocatalyst for Chitobiose Degradation

An unstudied β-N-acetylhexosaminidase (SnHex) from the soil bacterium Stackebrandtia nassauensis was successfully cloned and subsequently expressed as a soluble protein in Escherichia coli. Activity tests and the biochemical characterization of the purified protein revealed an optimum pH of 6.0 and a robust thermal stability at 50 °C within 24 h. The addition of urea (1 M) or sodium dodecyl sulfate (1% w/v) reduced the activity of the enzyme by 44% and 58%, respectively, whereas the addition of divalent metal ions had no effect on the enzymatic activity. PUGNAc (O-(2-acetamido-2-deoxy-D-glucopyranosylidene)amino-N-phenylcarbamate) strongly inhibited the enzyme in sub-micromolar concentrations. The β-N-acetylhexosaminidase was able to hydrolyze β1,2-linked, β1,3-linked, β1,4-linked, and β1,6-linked GlcNAc residues from the non-reducing end of various tested glycan standards, including bisecting GlcNAc from one of the tested hybrid-type N-glycan substrates. A mutational study revealed that the amino acids D306 and E307 bear the catalytically relevant side acid/base side chains. When coupled with a chitinase, the β-N-acetylhexosaminidase was able to generate GlcNAc directly from colloidal chitin, which showed the potential of this enzyme for biotechnological applications.