A Novel Simulation Model Significantly Improves Confidence in Canthotomy and Cantholysis Among Ophthalmology and Emergency Medicine Trainees.

BACKGROUND: Orbital compartment syndrome is a potentially blinding eye condition. Timely diagnosis and treatment are paramount to optimize visual outcomes. Lateral canthotomy and cantholysis is the definitive management and a required competency for emergency physicians and ophthalmologists. Lack of confidence in the procedure can result in delayed treatment and poor outcomes. OBJECTIVES: Our aim was to create a low-cost, realistic, simulation model to ensure trainees were confident in performing lateral canthotomy and cantholysis. METHODS: A model was created using equipment found in the emergency department. This model's efficacy was assessed using pre- and post-teaching questionnaires measuring learner's self-perceived confidence. RESULTS: Forty-seven emergency medicine and 18 ophthalmology registrars rated their confidence in the procedure using a 5-point Likert scale (1 = not very confident, 5 = extremely confident); 42% (n = 27) of participants felt 'quite confident' (4 on Likert scale) in carrying out the procedure unsupervised out of hours after the teaching session, compared with 9.23% (n = 6) before (p < 0.01). Our model resulted in significant increases in all three measures of confidence (diagnosing orbital compartment syndrome, locating the necessary equipment and performing canthotomy and cantholysis) and was rated as 4.35 (1 = not at all helpful, 5 = extremely helpful) in understanding the anatomy of the region. Sixty-six percent (n = 43) of participants stated they would like further simulation teaching. CONCLUSIONS: Our model is low cost, easy to assemble, and anatomically correct. The user can 'strum' the inferior canthal tendon without cutting the lower lid, appreciating the difference between canthotomy and cantholysis. Use of this model significantly increased the number of learners who felt "quite confident" with performing the procedure. Use of this model should be considered for trainees in ophthalmology and emergency medicine.

Persistent orbital inflammation following complete excision of deep dermoid cysts.

Piecemeal excision of dermoid cysts carries the risk of implanting epithelial fragments into orbital fat, which is well recognized to continue secreting oily debris, inciting chronic, often granulomatous inflammation. The authors present the clinical and histological details for two patients with persistent lipogranulomatous inflammation for years after piecemeal excision of deep orbital dermoid cysts, in the absence of any residual epithelium. The importance of copious saline lavage - to 'float-out" and reduce microscopic lipid droplets - is also emphasised.

Combined upper lid skin crease and endoscopic approach to frontal sinus mucocoeles.

PURPOSE: This case series describes the ophthalmic manifestations of frontal sinus mucoceles and reports the long-term surgical outcomes of a combined endoscopic and upper-lid skin crease drainage approach carried out jointly with otorhinolaryngology. METHODS: We present a retrospective case review of 18 orbits and 15 patients presenting with frontal sinus mucocoeles, all of whom underwent drainage via an adapted anterior orbitotomy approach between January 2015 and July 2023. Data collection included preoperative and postoperative examination findings (visual acuity, extraocular motility, lid retraction, and lagophthalmos), mucocoele recurrence, cosmetic satisfaction, and surgical complications. Patients were followed up for an average of 22 months. RESULTS: All patients underwent successful frontal mucocoele drainage via a modified anterior orbitotomy and simultaneous endonasal approach. At presentation, three (20%) had extraocular restriction leading to diplopia, and six (40%) had proptosis in the eye adjacent to the mucocoele. One patient presented acutely with no light perception in the affected eye due to compressive optic neuropathy. All patients who had reduced extraocular motility before surgery regained full motility post-operatively. Treatment was successful in all cases, and there was no documented mucocoele recurrence during follow-up. Satisfactory aesthetic outcomes were achieved in all cases. Reported complications included temporary forehead numbness and ptosis of the affected eyelid, which resolved without intervention. CONCLUSION: The modified anterior orbitotomy approach to frontal mucocoeles allows optimal frontal sinus access and mucocoele treatment while preserving cosmesis.

A multidisciplinary approach to frontal sinus mucocoeles using an upper lid skin crease incision combined with endoscopic drainage allows full access to the frontal sinus and treatment of the mucocoele while preserving cosmesis.

Translating the force-mechano-sensing GPCRs.

Incorporating mechanical cues into cellular responses allows us to experience our direct environment. Specialized cells can perceive and discriminate between different physical properties such as level of vibration, temperature, or pressure. Mechanical forces are abundant signals that also shape general cellular responses such as cytoskeletal rearrangement, differentiation, or migration and contribute to tissue development and function. The molecular structures that perceive and transduce mechanical forces are specialized cytoskeletal proteins, cell junction molecules, and membrane proteins such as ion channels and metabotropic receptors. G protein-coupled receptors (GPCRs) have attracted attention as metabotropic force receptors as they are among the most important drug targets. This review summarizes the function of mechano-sensitive GPCRs, specifically, the angiotensin II type 1 receptor and adrenergic, apelin, histamine, parathyroid hormone 1, and orphan receptors, focusing particularly on the advanced knowledge gained from adhesion-type GPCRs. We distinguish between shear stress and cell swelling/stretch as the two major types of mechano-activation of these receptors and contemplate the potential contribution of the force-from-lipid and force-from-tether models that have previously been suggested for ion channels.

Functional impact of intramolecular cleavage and dissociation of adhesion G protein-coupled receptor GPR133 (ADGRD1) on canonical signaling.

GPR133 (ADGRD1), an adhesion G protein-coupled receptor (GPCR) whose canonical signaling activates GαS-mediated generation of cytosolic cAMP, has been shown to be necessary for the growth of glioblastoma (GBM), a brain malignancy. The extracellular N terminus of GPR133 is thought to be autoproteolytically cleaved into N-terminal and C- terminal fragments (NTF and CTF, respectively). However, the role of this cleavage in receptor activation remains unclear. Here, we used subcellular fractionation and immunoprecipitation approaches to show that the WT GPR133 receptor is cleaved shortly after protein synthesis and generates significantly more canonical signaling than an uncleavable point mutant GPR133 (H543R) in patient-derived GBM cultures and HEK293T cells. After cleavage, the resulting NTF and CTF remain noncovalently bound to each other until the receptor is trafficked to the plasma membrane, where we demonstrated NTF-CTF dissociation occurs. Using a fusion of the CTF of GPR133 and the N terminus of thrombin-activated human protease-activated receptor 1 as a controllable proxy system to test the effect of intramolecular cleavage and dissociation, we also showed that thrombin-induced cleavage and shedding of the human protease-activated receptor 1 NTF increased intracellular cAMP levels. These results support a model wherein dissociation of the NTF from the CTF at the plasma membrane promotes GPR133 activation and downstream signaling. These findings add depth to our understanding of the molecular life cycle and mechanism of action of GPR133 and provide critical insights that will inform therapeutic targeting of GPR133 in GBM.

Congenital Conjunctival Cysts of the Orbit.

PURPOSE: To evaluate the clinical presentation, anatomical location, and histological features of congenital conjunctival cysts of the orbit. The location and the histological features of inflammation in these patients were compared with those for 293 orbital dermoid cysts. PATIENTS AND METHODS: Retrospective review of the clinical details, imaging, and histopathology for patients who had excision of conjunctival cysts from their orbit between 1992 and 2020; patients with a history of trauma or surgery were omitted. RESULTS: Twelve patients (7 male; 58%) with congenital conjunctival cysts were identified, the patients presenting at an average age of 16 years (median 26; range 1-61) with a symptoms for a mean duration of 20 months (median 24; range 6-36). The commonest symptoms were peribulbar lump (6/12 patients; 50%), and eyelid swelling and blepharoptosis (6/12 patients; 50%). An orbitaxl mass was palpable in 10 patients (83%), 3 patients (25%) had mild proptosis (1-3 mm), and the cysts were most commonly located superiorly (6/12 patients; 50%) or superonasally (3/12; 25%) in the anterior half of the orbit. Imaging was performed in 7 cases, this showing an intimate relation to the common sheath of the superior rectus/levator complex in 3 patients (25%) and to the trochlea in 1 (8%). All cysts were excised completely, and no patient had postoperative complications or recurrence. Chronic mild and nonspecific inflammation was evident within the cyst wall in 7 cases (54%), but-unlike 55% of the 293 dermoid cysts-none showed granuloma formation. CONCLUSION: Congenital conjunctival cysts are rare and usually present with a palpable mass in the upper eyelid sulcus. A significant proportion of these cysts have an intimate relationship with the trochlea, or the superior rectus, levator palpebrae or superior oblique muscles and, to minimize the risk of postoperative diplopia or ptosis, particular care must be exercised during surgery.

Orbital compartment syndrome following tear trough filler injection.

A patient was treated with tear trough filler and developed a retrobulbar haemorrhage. This was managed acutely with a lateral canthotomy and cantholysis with no lasting visual compromise. This is the first reported case of an orbital compartment syndrome following filler injection and highlights the potential blinding complications which can occur. There should be an increased awareness of this complication amongst practitioners administering tear trough filler.

Orbital Crystal-Storing Histiocytosis: A Clinicopathologic Study of 4 Cases.

The authors report the clinicopathological features of crystal-storing histiocytosis (CSH) that involved the orbit and conjunctiva and review published cases of CSH. Cases of histologically proven CSH were identified from archives at the Institute of Ophthalmology, London, and a retrospective review of clinical details and pathology was performed for cases between 1997 and 2017. Four cases of CSH were identified: 1 might have arisen from an inflammatory reaction to a silicone retinal buckle and 3 others occurred with localized B-cell lymphomas. Two patients presented with a conjunctival mass, and 2 had an orbital mass causing proptosis and hypoglobus. One case was associated with amyloid deposition and another had an earlier diagnosis of IgG4-related disease. In the patient without underlying lymphoma, the condition settled with removal of the explant and orbital mass, and the 3 with lymphoma underwent orbital radiotherapy with cessation of disease progression. All patients retained good vision. Ocular CSH is rare, can present in several ways, and should prompt investigation for an underlying lymphoproliferative disorder.

Activation of Adhesion G Protein-coupled Receptors: AGONIST SPECIFICITY OF STACHEL SEQUENCE-DERIVED PEPTIDES.

Members of the adhesion G protein-coupled receptor (aGPCR) family carry an agonistic sequence within their large ectodomains. Peptides derived from this region, called the Stachel sequence, can activate the respective receptor. As the conserved core region of the Stachel sequence is highly similar between aGPCRs, the agonist specificity of Stachel sequence-derived peptides was tested between family members using cell culture-based second messenger assays. Stachel peptides derived from aGPCRs of subfamily VI (GPR110/ADGRF1, GPR116/ADGRF5) and subfamily VIII (GPR64/ADGRG2, GPR126/ADGRG6) are able to activate more than one member of the respective subfamily supporting their evolutionary relationship and defining them as pharmacological receptor subtypes. Extended functional analyses of the Stachel sequences and derived peptides revealed agonist promiscuity, not only within, but also between aGPCR subfamilies. For example, the Stachel-derived peptide of GPR110 (subfamily VI) can activate GPR64 and GPR126 (both subfamily VIII). Our results indicate that key residues in the Stachel sequence are very similar between aGPCRs allowing for agonist promiscuity of several Stachel-derived peptides. Therefore, aGPCRs appear to be pharmacologically more closely related than previously thought. Our findings have direct implications for many aGPCR studies, as potential functional overlap has to be considered for in vitro and in vivo studies. However, it also offers the possibility of a broader use of more potent peptides when the original Stachel sequence is less effective.

The constitutive activity of the adhesion GPCR GPR114/ADGRG5 is mediated by its tethered agonist.

Adhesion GPCRs (aGPCRs) form the second largest, yet most enigmatic class of the GPCR superfamily. Although the physiologic importance of aGPCRs was demonstrated in several studies, the majority of these receptors is still orphan with respect to their agonists and signal transduction. Recent studies reported that aGPCRs are activated through a tethered peptide agonist, coined the Stachel sequence. The Stachel sequence is the most C-terminal part of the highly conserved GPCR autoproteolysis-inducing domain. Here, we used cell culture-based assays to investigate 2 natural splice variants within the Stachel sequence of the orphan Gs coupling aGPCR GPR114/ADGRG5. There is 1 variant constitutively active in cAMP assays (∼25-fold over empty vector) and sensitive to mechano-activation. The other variant has low basal activity in cAMP assays (6-fold over empty vector) and is insensitive to mechano-activation. In-depth mutagenesis studies of these functional differences revealed that the N-terminal half of the Stachel sequence confers the agonistic activity, whereas the C-terminal part orientates the agonistic core sequence to the transmembrane domain. Sequence comparison and functional testing suggest that the proposed mechanism of Stachel-mediated activation is relevant not only to GPR114 but to aGPCRs in general.

Functional relevance of naturally occurring mutations in adhesion G protein-coupled receptor ADGRD1 (GPR133).

BACKGROUND: A large number of human inherited and acquired diseases and phenotypes are caused by mutations in G protein-coupled receptors (GPCR). Genome-wide association studies (GWAS) have shown that variations in the ADGRD1 (GPR133) locus are linked with differences in metabolism, human height and heart frequency. ADGRD1 is a Gs protein-coupled receptor belonging to the class of adhesion GPCRs. RESULTS: Analysis of more than 1000 sequenced human genomes revealed approximately 9000 single nucleotide polymorphisms (SNPs) in the human ADGRD1 as listed in public data bases. Approximately 2.4 % of these SNPs are located in exons resulting in 129 non-synonymous SNPs (nsSNPs) at 119 positions of ADGRD1. However, the functional relevance of those variants is unknown. In-depth characterization of these amino acid changes revealed several nsSNPs (A448D, Q600stop, C632fs [frame shift], A761E, N795K) causing full or partial loss of receptor function, while one nsSNP (F383S) significantly increased basal activity of ADGRD1. CONCLUSION: Our results show that a broad spectrum of functionally relevant ADGRD1 variants is present in the human population which may cause clinically relevant phenotypes, while being compatible with life when heterozygous.

Retinal structure and function in achromatopsia: implications for gene therapy.

PURPOSE: To characterize retinal structure and function in achromatopsia (ACHM) in preparation for clinical trials of gene therapy. DESIGN: Cross-sectional study. PARTICIPANTS: Forty subjects with ACHM. METHODS: All subjects underwent spectral domain optical coherence tomography (SD-OCT), microperimetry, and molecular genetic testing. Foveal structure on SD-OCT was graded into 5 distinct categories: (1) continuous inner segment ellipsoid (ISe), (2) ISe disruption, (3) ISe absence, (4) presence of a hyporeflective zone (HRZ), and (5) outer retinal atrophy including retinal pigment epithelial loss. Foveal and outer nuclear layer (ONL) thickness was measured and presence of hypoplasia determined. MAIN OUTCOME MEASURES: Photoreceptor appearance on SD-OCT imaging, foveal and ONL thickness, presence of foveal hypoplasia, retinal sensitivity and fixation stability, and association of these parameters with age and genotype. RESULTS: Forty subjects with a mean age of 24.9 years (range, 6-52 years) were included. Disease-causing variants were found in CNGA3 (n = 18), CNGB3 (n = 15), GNAT2 (n = 4), and PDE6C (n = 1). No variants were found in 2 individuals. In all, 22.5% of subjects had a continuous ISe layer at the fovea, 27.5% had ISe disruption, 20% had an absent ISe layer, 22.5% had an HRZ, and 7.5% had outer retinal atrophy. No significant differences in age (P = 0.77), mean retinal sensitivity (P = 0.21), or fixation stability (P = 0.34) across the 5 SD-OCT categories were evident. No correlation was found between age and foveal thickness (P = 0.84) or between age and foveal ONL thickness (P = 0.12). CONCLUSIONS: The lack of a clear association of disruption of retinal structure or function in ACHM with age suggests that the window of opportunity for intervention by gene therapy is wider in some individuals than previously indicated. Therefore, the potential benefit for a given subject is likely to be better predicted by specific measurement of photoreceptor structure rather than simply by age. The ability to directly assess cone photoreceptor preservation with SD-OCT and/or adaptive optics imaging is likely to prove invaluable in selecting subjects for future trials and measuring the trials' impact.

Wine yeast typing by MALDI-TOF MS.

For the production of wine, the most important industrially used yeast species is Saccharomyces cerevisiae. Years of experience have shown that wine quality and property are significantly affected by the employed strain conducting the fermentation. Consequently, the ability of a strain level differentiation became an important requirement of modern winemaking. In our study, we showed that the differentiation by time-consuming and laborious biochemical and DNA-based methods to enable a constant beverage quality and characteristics can be replaced by matrix-assisted-laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), accompanied by the additional benefit of an application prediction. Mass fingerprints of 33 Saccharomyces strains, which are commonly used for varying wine fermentations, were generated by MALDI-TOF MS upon optimized sample preparation and instrument settings and analyzed by a cluster analysis for strain or ecotype-level differentiation. As a reference method, delta-PCR was chosen to study the genetic diversity of the employed strains. Finally, the cluster analyses of both methods were compared. It could be shown that MALDI-TOF MS, acting at proteome level, provides valuable information about the relationship between yeast strains and their application potential according to their MALDI mass fingerprint.

The Posthyaluronidase Syndrome: Dosing Strategies for Hyaluronidase in the Dissolving of Facial Filler and Independent Predictors of Poor Outcomes.

Background: Hyaluronic acid dermal fillers are used extensively in periocular aesthetic medicine, and the incidence of filler-related complications is increasing. This study aimed to investigate the optimal dosing strategy for hyaluronidase and to identify predictors of poor outcomes. Methods: We performed a retrospective review of 157 orbits of 90 patients treated with hyaluronidase over a 4-year period. Demographic data, indication, and details of hyaluronidase treatment and outcomes were recorded. Results: The primary indication for dissolving filler was swelling in 52%, lumpiness in 20%, and before surgical blepharoplasty in 17%. The most frequently used hyaluronidase concentration was 150 U per mL in 66%, followed by 75 U per mL in 31%, 37.5 U per mL in 3%, and 100 U per mL in 1%. Outcomes were characterized as follows: 59% with a satisfactory result; 24% as insufficient treatment requiring further hyaluronidase; and 18% complaining of facial changes such as hollowing, indicating a post hyaluronidase syndrome. There was no statistical difference in outcomes between the 75 and 150 U per mL dosage groups (P = 0.625). A significant correlation was identified between posthyaluronidase syndrome and duration of filler in situ (P = 0.00019) and volume of filler (P = 0.000017). Conclusions: The posthyaluronidase syndrome may be related to previous filler volume and duration, rather than the concentration or dose of hyaluronidase used. All patients should be informed about the risks of adverse effects after hyaluronidase treatment; patients with longer histories of filler use and higher total volumes should be advised of the increased risk.

Presenting features for developmental cysts of the orbit.

PURPOSE: To evaluate the clinical features of developmental cysts of the orbit. PATIENTS AND METHODS: Retrospective study of patients who had excision of cysts between 1992 and 2020. RESULTS: Three hundred and 58 patients (189 male; 53%) with orbital developmental cysts were identified, all being unilateral. Age at surgery varied from birth to 77 years (mean 17, median 18 years) and the average symptom duration was 5 years (median 18 months; range 1 day-50 years). The commonest presenting features were a peribulbar lump or upper lid swelling, followed by proptosis, pain, diplopia and reduced vision. Most patients (82%) had a palpable mass, with epidermoids, sebaceous dermoids and keratinised dermoids commonly affecting the superotemporal quadrant, and conjunctiva-containing cysts usually being biased to a medial location. Cysts were lined by keratinised epithelium with dermal structures (224/358; 63%), non-keratinised epithelium with dermal structures (69/358; 19%), epidermis without identifiable dermal structures (19/358 'epidermoids'; 5%), conjunctiva (12/358; 3%), respiratory epithelium (4/358; 1%), or mixed dermal and conjunctival epithelia (30/358 'dermo-conjunctival' cysts; 8%). Overall, two-thirds (242/358; 66%) had histological evidence of chronic intramural inflammation, and a half of cysts showed granuloma formation (178/358 cysts). Chronic inflammation was less common with conjunctival cysts (54%, 7/12 patients) and none showed granuloma formation. CONCLUSION: Developmental cysts of the orbit vary from the relatively common dermoid cysts to the extremely rare respiratory epithelial-lined cysts. Respiratory cysts, being deeper, may present late in life and cysts containing conjunctival epithelium tend to be less inflamed and typically favour the superonasal quadrant.

Tear Trough Filler Using the Three-point Tangent Technique: Lessons from 1452 Tear Trough Applications.

This study describes a novel three-point tangent technique for tear trough filler and the results from the largest series to date. Methods: A retrospective case review was performed for all patients treated between 2016 and 2020. Patient demographics, filler details and complications were recorded. The injection technique involves using a blunt cannula to deliver filler along three linear tangents bespoke to each patient. Results: A total of 1452 applications of filler to the orbits of 583 patients were recorded. The median patient age was 41 years (range 19-77), and 84% were women. The mean volume of applied filler at the first appointment was 0.34 mL to each orbit (range 0.1--1.5); 82% reported no complication, 10% reported swelling with a median duration of 4 weeks (range 1-52), 4.3% experienced bruising, 4.6% reported contour irregularities, and 3.3% experienced a Tyndall effect. Retrobulbar hemorrhage occurred in one patient (0.17%), which was managed immediately with no lasting visual compromise. Volume of filler injected was significantly associated with a risk of edema (P < 0.00001) and contour irregularities (P = 0.012). In total, 50% of cases of edema resolved spontaneously after 4 weeks. Filler was dissolved in 1.9% of orbits. Patients with a history of dissolving were significantly more likely to require dissolving after subsequent reinjection (P = 0.043). Conclusions: The three-point tangent technique is a safe and effective method. Increasing volume of filler administered is associated with complications of edema and contour irregularities. Edema is the most common complication and resolves spontaneously in half of patients by 4 weeks.

Collagen VI Is a Gi-Biased Ligand of the Adhesion GPCR GPR126/ADGRG6.

GPR126/ADGRG6, a member of the adhesion G-protein-coupled receptor family, balances cell differentiation and proliferation through fine-tuning of intracellular cAMP levels, which is achieved through coupling to Gs and Gi proteins. While GPR126-mediated cAMP increase has been proven to be essential for differentiation of Schwann cells, adipocytes and osteoblasts, Gi-signaling of the receptor was found to propagate breast cancer cell proliferation. Extracellular ligands or mechanical forces can modulate GPR126 activity but require an intact encrypted agonist sequence, coined the Stachel. Even though coupling to Gi can be seen for constitutively active truncated receptor versions of GPR126 as well as with a peptide agonist derived from the Stachel sequence, all known N-terminal modulators have so far only been shown to modulate Gs coupling. Here, we identified collagen VI as the first extracellular matrix ligand of GPR126 that induces Gi signaling at the receptor, which shows that N-terminal binding partners can mediate selective G protein signaling cascades that are masked by fully active truncated receptor variants.

PTK7 is a positive allosteric modulator of GPR133 signaling in glioblastoma.

The adhesion G-protein-coupled receptor GPR133 (ADGRD1) supports growth of the brain malignancy glioblastoma. How the extracellular interactome of GPR133 in glioblastoma modulates signaling remains unknown. Here, we use affinity proteomics to identify the transmembrane protein PTK7 as an extracellular binding partner of GPR133 in glioblastoma. PTK7 binds the autoproteolytically generated N-terminal fragment of GPR133 and its expression in trans increases GPR133 signaling. This effect requires the intramolecular cleavage of GPR133 and PTK7's anchoring in the plasma membrane. PTK7's allosteric action on GPR133 signaling is additive with but topographically distinct from orthosteric activation by soluble peptide mimicking the endogenous tethered Stachel agonist. GPR133 and PTK7 are expressed in adjacent cells in glioblastoma, where their knockdown phenocopies each other. We propose that this ligand-receptor interaction is relevant to the pathogenesis of glioblastoma and possibly other physiological processes in healthy tissues.

Expression of a library of fungal ß-glucosidases in Saccharomyces cerevisiae for the development of a biomass fermenting strain.

Converting cellulosic biomass to ethanol involves the enzymatic hydrolysis of cellulose and the fermentation of the resulting glucose. The yeast Saccharomyces cerevisiae is naturally ethanologenic, but lacks the enzymes necessary to degrade cellulose to glucose. Towards the goal of engineering S. cerevisiae for hydrolysis of and ethanol production from cellulose, 35 fungal ß-glucosidases (BGL) from the BGL1 and BGL5 families were screened for their ability to be functionally expressed and displayed on the cell surface. Activity assays revealed that the BGL families had different substrate specificities, with only the BGL1s displaying activity on their natural substrate, cellobiose. However, growth on cellobiose showed no correlation between the specific growth rates, the final cell titer, and the level of BGL1 activity that was expressed. One of the BGLs that expressed the highest levels of cellobiase activity, Aspergillus niger BGL1 (Anig-Bgl101), was then used for further studies directed at developing an efficient cellobiose-fermenting strain. Expressing Anig-Bgl101 from a plasmid yielded higher ethanol levels when secreted into the medium rather than anchored to the cell surface. In contrast, ethanol yields from anchored and secreted Anig-Bgl101 were comparable when integrated on the chromosome. Flow cytometry analysis revealed that chromosomal integration of Anig-Bgl101 resulted in a higher percentage of the cell population that displayed the enzyme but with overall lower expression levels.