Selective cysteine-to-selenocysteine changes in a [NiFe]-hydrogenase confirm a special position for catalysis and oxygen tolerance.

In [NiFe]-hydrogenases, the active-site Ni is coordinated by four cysteine-S ligands (Cys; C), two of which are bridging to the Fe(CO)(CN)2 fragment. Substitution of a single Cys residue by selenocysteine (Sec; U) occurs occasionally in nature. Using a recent method for site-specific Sec incorporation into proteins, each of the four Ni-coordinating cysteine residues in the oxygen-tolerant Escherichia coli [NiFe]-hydrogenase-1 (Hyd-1) has been replaced by U to identify its importance for enzyme function. Steady-state solution activity of each Sec-substituted enzyme (on a per-milligram basis) is lowered, although this may reflect the unquantified presence of recalcitrant inactive/immature/misfolded forms. Protein film electrochemistry, however, reveals detailed kinetic data that are independent of absolute activities. Like native Hyd-1, the variants have low apparent KMH2 values, do not produce H2 at pH 6, and display the same onset overpotential for H2 oxidation. Mechanistically important differences were identified for the C576U variant bearing the equivalent replacement found in native [NiFeSe]-hydrogenases, its extreme O2 tolerance (apparent KMH2 and Vmax [solution] values relative to native Hyd-1 of 0.13 and 0.04, respectively) implying the importance of a selenium atom in the position cis to the site where exogenous ligands (H-, H2, O2) bind. Observation of the same unusual electrocatalytic signature seen earlier for the proton transfer-defective E28Q variant highlights the direct role of the chalcogen atom (S/Se) at position 576 close to E28, with the caveat that Se is less effective than S in facilitating proton transfer away from the Ni during H2 oxidation by this enzyme.

Underlying intracranial atherosclerotic disease is associated with worse outcomes in acute large vessel occlusion undergoing endovascular thrombectomy.

BACKGROUND: Data on large vessel occlusion (LVO) management due to intracranial atherosclerotic disease (ICAD) are scarce. OBJECTIVE: To compare clinical outcomes between patients with ICAD and those without ICAD following mechanical thrombectomy (MT). METHODS: We performed a retrospective analysis of consecutive patients who underwent MT for LVO in a large academic comprehensive stroke center, and compared in-hospital mortality, 90-day mortality, favorable functional outcome at 90 days, and symptomatic intracranial hemorrhage (ICH) using chi-squared tests and multivariate logistic regression analyses. We defined ICAD as observable plaque at occlusion site post-thrombectomy. RESULTS: Among 215 patients (mean age 67.1 ± 16.0 years; 60.5% female; 83.6% Black, median NIHSS score 16), ICAD was present in 38 patients (17.7%). Diabetes and dyslipidemia were more common in those with ICAD (57.9% vs. 38.4%, p = 0.027 and 29.0% vs. 14.7%, p = 0.035, respectively). Substantial reperfusion (TICI ≥2b) was achieved less often (84.2% vs. 94.4%, p = 0.031) but symptomatic ICH was also less common in ICAD patients (0% vs. 9.0%, p = 0.081). In-hospital and 90-day mortality were more common (36.8% vs. 15.8%, p = 0.003 and 52.6% vs. 26.6%, p = 0.002, respectively) and favorable functional outcome (mRS 0-2) at 90 days was less common (7.9% vs. 33.9%, p = 0.001) in ICAD patients. After adjusting for prognostic variables, ICAD was independently associated with in-hospital mortality (OR=4.1, 95% CI 1.7-9.7), 90-day mortality (OR=3.7, 95% CI 1.6-8.6), and poor functional outcome at 90 days (OR=5.5, 95% CI 1.6-19.4). CONCLUSION: Symptomatic ICAD in a predominantly African American cohort is associated with increased odds of mortality and poor functional outcome at 90 days in patients with LVO undergoing MT.

Benevolent Sexism and the Traditional Sexual Script as Predictors of Sexual Dissatisfaction in Heterosexual Women from the U.S.

Women report lower sexual satisfaction than men. Given that sexual dissatisfaction adversely impacts health and well-being, it is imperative that we investigate why women are sexually dissatisfied. In the present study, we explored whether women's benevolently sexist attitudes might predict their sexual dissatisfaction. In a sample of 308 (Mage = 38.09) heterosexual American women who had previously had sex with a man, we hypothesized that women's benevolent sexism would be associated with an increased adoption of the traditional sexual script (i.e., an increased propensity for submissiveness and passivity during sex) and that this, in turn, would be associated with increased sexual dissatisfaction. We also hypothesized that the relationship between the adoption of the traditional sexual script and sexual dissatisfaction would be moderated by the degree to which participants enjoy submissiveness. Overall, we did not find support for our model: benevolent sexism did not predict sexual dissatisfaction. However, we did find that adopting the traditional sexual script was predictive of sexual dissatisfaction for women who do not enjoy submissiveness. These findings contribute to an emerging literature pertaining to women's sexual health. Specifically, results suggest that benevolent sexism does not contribute to women's experiences of sexual dissatisfaction. Instead, they suggest that sexual dissatisfaction in women may (in part) be driven by their engagement in sexual roles that do not align with their sexual preferences. Theoretical and clinical implications for these findings are discussed.

Association between hidradenitis suppurativa, depression, anxiety, and suicidality: A systematic review and meta-analysis.

BACKGROUND: Previous studies found conflicting results about whether hidradenitis suppurativa (HS) is associated with depression or anxiety. OBJECTIVES: To determine the relationship of HS with depression and anxiety. METHODS: A systematic review was performed of published observational studies in MEDLINE, PubMed, Embase, Global Resource for Eczema Trials (GREAT), Latin American and Caribbean Health Sciences Literature (LILACS), Cochrane, Scopus, and PsychInfo that analyzed depression or anxiety in HS. Two reviewers performed title/abstract review and data extraction. Meta-analysis was performed with random-effects weighting. RESULTS: Thirty-eight studies met inclusion criteria; 27 had sufficient data for meta-analysis. The prevalences of depression (26.5% vs 6.6%) and anxiety (18.1% vs 7.1%) were higher in persons with versus without HS. Patients with HS had higher odds of depression in 12 of 13 studies and pooled analysis (odds ratio, 2.54; 95% confidence interval, 2.15-3.01), and anxiety in 6 of 6 studies and pooled analysis (odds ratio, 2.00; 95% confidence interval, 1.66-2.42). Similar results were found in sensitivity analyses for different methods of HS diagnosis (physician diagnosed and chart review) and control groups (healthy and dermatologic control individuals). HS was associated with higher antidepressant and anxiolytic use and with suicidality, but not mean depression and anxiety scale scores. LIMITATIONS: Individual-level data were unavailable. CONCLUSIONS: Patients with HS have higher odds of depression, anxiety, and suicidality.

Placebo responses in randomized controlled trials for systemic therapy in atopic dermatitis: A systematic review and meta-analysis.

BACKGROUND: Atopic dermatitis (AD) has a variable disease course and intermittent triggers, and responses to topical therapy vary, potentially affecting the magnitude of the placebo response in AD trials. OBJECTIVE: To determine the predictors of increased placebo response in randomized controlled trials of AD. METHODS: We performed a systematic review and meta-analysis of randomized controlled trials for systemic therapy in AD published during 2007-2018. We searched the Cochrane Library, Medline, Embase, Global Resource for EczemA Trials (GREAT), Literature of the Latin American and Caribbean Health Sciences (LILACS), and Scopus. Two authors performed study selection and data extraction. Multivariable mixed models were constructed for Cohen D of Eczema Area and Severity Index (EASI), SCORing Atopic Dermatitis (SCORAD), numeric rating scale (NRS)-itch and visual analog scale (VAS)-itch, and Dermatology Life Quality Index (DLQI). RESULTS: Overall, 64 trials were included. Use of concomitant topical therapy prescriptions, study duration ≥3 months, and fewer treatment arms were associated with an increased placebo response for EASI, NRS- and VAS-itch, and DLQI. For EASI, the placebo response was increased in studies with a higher proportion of male patients, mild-moderate mean baseline EASI scores, and no blinding. For NRS-itch, and VRS-itch, higher placebo responses were associated with higher proportions of male patients and moderate-severe mean itch scores at baseline. CONCLUSION: Placebo responses can be reduced in clinical trials of systemic therapy in AD by incorporating double- and triple-blinding, balancing the sex distribution of patients, disallowing concomitant use of prescription topical therapy, and having shorter study durations.

Epidemiology of alopecia areata, ophiasis, totalis, and universalis: A systematic review and meta-analysis.

BACKGROUND: Alopecia areata (AA) is a common autoimmune alopecia with heterogeneous severity and distribution. Previous studies found conflicting results about AA epidemiology. OBJECTIVE: To determine the prevalence, incidence, and predictors of AA, alopecia totalis, alopecia ophiasis, and alopecia universalis. METHODS: A systematic review of all published cohort and cross-sectional studies that analyzed AA and its subtypes. MEDLINE, Embase, LILACS, Scopus, Cochrane Library, and GREAT were searched. At least 2 reviewers performed study title/abstract review and data extraction. Random-effects meta-analysis was used because of significant heterogeneity (I2 = 99.97%). RESULTS: Ninety-four studies met the inclusion criteria. The pooled prevalence (95% confidence interval, N) of AA overall was 2.11% (1.82-2.42, N = 302,157,365), with differences of population-based (0.75% [0.49-1.06%], N = 301,173,403) and clinic-based (3.47% [3.01-3.96], N = 983,962) studies. The prevalences of alopecia totalis, ophiasis, and universalis were 0.08% (0.04-0.13, N = 1,088,149), 0.02% (0.00-0.06, N = 1,075,203), and 0.03% (0.01-0.06, N = 1,085,444), respectively. AA prevalence (95% confidence interval) increased over time (<2000: 1.02% [0.85-1.22]; 2000-2009: 1.76% [1.51-2.03]; >2009: 3.22% [2.59-3.92]; P < .0001) and differed by region. AA prevalence was significantly lower in adults (1.47% [1.18-1.80]) than children (1.92% [1.31-2.65]; P < .0001). CONCLUSIONS: AA affects 2% of the global population. AA prevalence is lower in adults than children, is increasing over time, and significantly differs by region.

Evaluation of cerebral oxygen perfusion during shoulder arthroplasty performed in the semi-beach chair position.

BACKGROUND: The beach chair position is commonly used when performing shoulder arthroplasty. However, this position has been associated with hypotension, potentially leading to cerebral hypoperfusion, which may cause neurologic injury. In addition, shoulder arthroplasty cases are associated with longer operative times, posing a potentially greater risk of cerebral hypoperfusion. We aim to evaluate the risk of cerebral desaturation events (CDEs) during the course of total shoulder arthroplasty. METHODS: Twenty-six patients undergoing shoulder arthroplasties were monitored for changes in cerebral perfusion. Seven specific time-points during the procedure were labeled for comparison of events: baseline, beach chair, incision, humeral broaching, glenoid reaming, glenoid component implantation, and humeral component implantation. Cerebral oxygen perfusion was measured using near-infrared spectroscopy. A CDE was described as a decrease of oxygen saturation greater than 20%. RESULTS: Nineteeen of 25 subjects experienced a CDE. 42% of these patients experienced CDEs during semi-beach chair positioning. Patients experienced the largest oxygen saturation drop during semi-beach chair positioning. Transition from baseline to semi-beach chair was the only event to have a statistically significant decrease in cerebral perfusion (8%, P < .05). There was a statistically significant percentage change in mean oxygen saturation in the semi-beach chair interval (10%, P < .01) and the semi-beach chair to incision interval (7%, P < .01). CONCLUSIONS: Most patients experienced an intraoperative CDE, with greatest incidence during semi-beach chair positioning. The largest decline in cerebral oxygen saturation occurred during semi-beach chair positioning. Implant implantation was not associated with decrease in cerebral oximetry.

Protective Effects of Facilitated Removal of Blood Alcohol and Acetaldehyde Against Liver Injury in Animal Models Fed Alcohol and Anti-HIV Drugs.

BACKGROUND: We previously developed enzyme nanoparticles (ENP) of alcohol metabolism. This study was to evaluate protective effects of facilitated removal of blood alcohol and/or acetaldehyde on anti-HIV drugs and alcohol-induced liver injuries. METHODS: ENP were prepared for degrading alcohol completely (ENP1) or partially into acetaldehyde (ENP2), which were applied to mice of acute binge or chronic-binge alcohol feeding in the presence of antivirals (ritonavir and lopinavir). Liver pathologies were examined to assess the protective effects of ENP. RESULTS: In the acute model, ENP1 and ENP2 reduced the blood alcohol concentration (BAC) by 41 and 32%, respectively, within 4 hr, whereas in control without ENP, BAC was reduced only by 15%. Blood acetaldehyde concentration (BADC) was increased by 39% in alcohol-fed mice treated with ENP2 comparing to control. No significant effects of the anti-HIV drugs on BAC or BADC were observed. Plasma alanine aminotransferase (ALT) and expression of liver TNF-α were both significantly increased in the alcohol-fed mice, which were normalized by ENP1. In the presence of the antivirals, ALT was partially reduced by ENP1 or ENP2. In the chronic model, inflammation, fatty liver, and ALT were increased, which were deteriorated by the antivirals. ENP1 partially reduced BAC, BADC, ALT, and expression of inflammation markers of TNF-α, F4/80, and IL-6 and lipogenic factors of ACC, LXRα, and SREBP1. ENP2 reduced BAC without significant effects on ALT, inflammation, or lipogenesis. Antivirals and alcohol synergistically increased expression of organelle stress markers of CHOP, sXBP-1, ATF6, and GCP60. ENP1 reduced BAC, CHOP, and sXbp-1. However, no effects of ENP1 were found on ATF6 or GCP60. CONCLUSIONS: Removal of blood alcohol and acetaldehyde by the ENP protects the liver against alcoholic injuries, and the protection is less effective in chronic alcohol and antiviral feeding due to additional drug-induced organelle stresses.

A systematic review and meta-analysis of the prevalence and phenotype of adult-onset atopic dermatitis.

BACKGROUND: Previous studies found conflicting results about whether atopic dermatitis (AD) begins in adulthood. OBJECTIVE: To determine rates, predictors, and phenotypic differences of adult-onset AD. METHODS: A systematic review was performed with all published observational studies in Medline, Embase, GREAT (Global Resource of EczemA Trials), LILACS (Latin American and Caribbean Health Sciences Literature), Cochrane Library, and Scopus that analyzed the age of AD onset beyond 10 years of age. At least two reviewers performed study title, abstract review, and data extraction. Pooled meta-analysis of the proportion of adult-onset AD was performed by using random-effects weighting (I2 = 99.3%). RESULTS: Overall, 25 studies met inclusion criteria. Seventeen studies reported age of AD onset as after 16 years of age and had sufficient data for meta-analysis. The pooled proportion (95% confidence interval) of adult-onset AD was 26.1% (16.5%-37.2%). Similar results were found in sensitivity analyses by AD diagnostic method, study region, and sex. Phenotypic differences were observed across studies for adult-onset and child-onset AD, including higher rates of foot dermatitis and personal history of atopy but lower rates of flexural lesions and other signs and symptoms. LIMITATIONS: Characteristics of adult-onset versus child-onset AD were not commonly reported. CONCLUSION: AD is not only a disease of childhood; 1 in 4 adults with AD report adult-onset disease, which has distinct clinical characteristics as compared to child-onset AD.

Association of Psoriasis with Psychiatric Hospitalization in United States Children and Adults.

BACKGROUND: Psoriasis is associated with psychosocial distress. Little is known about the relationship between psoriasis and mental health (MH) emergencies. OBJECTIVE: To examine the associations of psoriasis and MH hospitalizations in the USA. METHODS: Data from the 2002-2012 National Inpatient Sample were analyzed, including an approximately 20% sample of all US hospitalizations (n = 87,053,155 children and adults). RESULTS: Hospitalization for MH disorders occurred more commonly in those with psoriasis compared to those without psoriasis (4.04 vs. 2.21%). In multivariable logistic regression models, psoriasis was associated with higher odds of admission for any MH disorder overall (adjusted odds ratio [95% confidence interval]: 2.32 [2.24-2.41]), as well as 9 of the 15 MH-specific disorders examined. Associated MH disorders included: anxiety, schizophrenia, personality disorder, depression, substance use disorders, history of MH disorder, alcohol-related disorders, adjustment disorders, and cognitive disorders. Children with versus those without psoriasis were also more likely to have a primary hospitalization for any MH disorder (2.82 [2.24-3.56]). Psoriasis inpatients were also more likely to have a primary hospitalization for any MH disorder compared to those with alopecia areata (1.99 [1.45-2.74]) or hidradenitis suppurativa (3.97 [3.49-4.52]). Psoriasis patients hospitalized with any MH disorder had higher mean [95% confidence interval] cost of inpatient care (USD 11,004 [10,846-11,241] vs. 9,547 [8,730-10,364]; p < 0.0001) compared to those without psoriasis, with USD 1,610,860 excess costs annually, with the majority of the costs coming from depression and mood disorders. CONCLUSIONS: Children and adults with psoriasis had increased hospitalization for multiple MH disorders, which were associated with a considerable financial burden.

Photo-stability study of a solution-processed small molecule solar cell system: correlation between molecular conformation and degradation.

Solution-processed organic small molecule solar cells (SMSCs) have achieved efficiency over 11%. However, very few studies have focused on their stability under illumination and the origin of the degradation during the so-called burn-in period. Here, we studied the burn-in period of a solution-processed SMSC using benzodithiophene terthiophene rhodamine:[6,6]-phenyl C71 butyric acid methyl ester (BTR:PC71BM) with increasing solvent vapour annealing time applied to the active layer, controlling the crystallisation of the BTR phase. We find that the burn-in behaviour is strongly correlated to the crystallinity of BTR. To look at the possible degradation mechanisms, we studied the fresh and photo-aged blend films with grazing incidence X-ray diffraction, UV-vis absorbance, Raman spectroscopy and photoluminescence (PL) spectroscopy. Although the crystallinity of BTR affects the performance drop during the burn-in period, the degradation is found not to originate from the crystallinity changes of the BTR phase, but correlates with changes in molecular conformation - rotation of the thiophene side chains, as resolved by Raman spectroscopy which could be correlated to slight photobleaching and changes in PL spectra.

Effects of combined alcohol and anti-HIV drugs on cellular stress responses in primary hepatocytes and hepatic stellate and kupffer cells.

BACKGROUND: Certain anti-HIV drugs alone or in combination are often associated with liver damages, which are frequently worsened by alcohol consumption. We previously found an endoplasmic reticulum (ER) stress mechanism for the drug- and alcohol-induced hepatic injuries in animal models and in vitro hepatocytes. However, it is unknown whether anti-HIV drugs and alcohol induce similar cellular stress responses and injuries in liver nonparenchymal cells. METHODS: Primary mouse hepatocytes (PMH), kupffer cells (KC), and hepatocellular stellate cells (HSC) were freshly isolated from mouse liver and treated with DMSO, stress-inducing pharmaceutical agents, alcohol alone, or in combination with antiviral ritonavir (RIT), lopinavir (LOP), or efavirenz (EFV). Expression of cellular stress markers, protein colocalization, and cell death were analyzed with immunoblotting, immunocytochemistry, and positive double staining with Sytox green and Hoechst blue, respectively. RESULTS: Expression of the ER stress markers of BiP, CHOP, and SERCA and the autophagy marker LC3 was significantly changed in PMH in response to combined alcohol, RIT, and LOP, which was companied by increased cell death compared with control. In contrast, although pharmaceutical agents induced ER stress and cell death, no significant ER stress or cell death was found in KC treated with alcohol, RIT, LOP, and EFV singly or in combination. In HSC, alcohol, RIT, LOP, or EFV induced BiP, but not CHOP, SERCA, or cell death compared with vehicle control. Further in PMH, RIT and LOP or in combination with alcohol-induced dose-dependent inhibition of ß-actin. Inhibition of ß-actin by RIT and LOP was companied with an inhibited nuclear expression of the antioxidant response regulator Nrf2 and reduced GST downstream of Nrf2. Ascorbic acid treatment reduced the alcohol-, RIT-, and LOP-induced cell death. CONCLUSIONS: The data suggest for the first time that sensitivities of hepatocytes and nonparenchymal cells to alcohol and anti-HIV drugs in vitro are different in terms of cellular stress response and cell death injury. Oxidative stress mediated by Nrf2 contributes to the alcohol- and drug-induced toxicity in the hepatocytes.

Visualizing orthogonal RNAs simultaneously in live mammalian cells by fluorescence lifetime imaging microscopy (FLIM).

Visualization of RNAs in live cells is critical to understand biology of RNA dynamics and function in the complex cellular environment. Detection of RNAs with a fluorescent marker frequently involves genetically fusing an RNA aptamer tag to the RNA of interest, which binds to small molecules that are added to live cells and have fluorescent properties. Engineering efforts aim to improve performance and add versatile features. Current efforts focus on adding multiplexing capabilities to tag and visualize multiple RNAs simultaneously in the same cell. Here, we present the fluorescence lifetime-based platform Riboglow-FLIM. Our system requires a smaller tag and has superior cell contrast when compared with intensity-based detection. Because our RNA tags are derived from a large bacterial riboswitch sequence family, the riboswitch variants add versatility for using multiple tags simultaneously. Indeed, we demonstrate visualization of two RNAs simultaneously with orthogonal lifetime-based tags.

Psilocybin's Potential Mechanisms in the Treatment of Depression: A Systematic Review.

Evidence suggests that psilocybin has therapeutic benefit for treating depression. However, there is little consensus regarding the mechanism by which psilocybin elicits antidepressant effects. This systematic review summarizes existing evidence. Ovid MEDLINE, EMBASE, psychINFO, and Web of Science were searched, for both human and animal studies, using a combination of MeSH Terms and free-text keywords in September 2021. No other mood disorders or psychiatric diagnoses were included. Original papers in English were included. The PRISMA framework was followed for the screening of papers. Two researchers screened the retrieved articles from the literature search, and a third researcher resolved any conflicts. Of 2,193 papers identified, 49 were selected for full-text review. 14 articles were included in the qualitative synthesis. Six supported psilocybin's mechanism of antidepressant action via changes to serotonin or glutamate receptor activity and three papers found an increase in synaptogenesis. Thirteen papers investigated changes in non-receptor or pathway-specific brain activity. Five papers found changes in functional connectivity or neurotransmission, most commonly in the hippocampus or prefrontal cortex. Several neuroreceptors, neurotransmitters, and brain areas are thought to be involved in psilocybin's ability to mitigate depressive symptoms. Psilocybin appears to alter cerebral blood flow to the amygdala and prefrontal cortex, but the evidence on changes in functional connectivity and specific receptor activity remains sparse. The lack of consensus between studies suggests that psilocybin's mechanism of action may involve a variety of pathways, demonstrating the need for more studies on psilocybin's mechanism of action as an antidepressant.

Establishing Riboglow-FLIM to visualize noncoding RNAs inside live zebrafish embryos.

The central role of RNAs in health and disease calls for robust tools to visualize RNAs in living systems through fluorescence microscopy. Live zebrafish embryos are a popular system to investigate multicellular complexity as disease models. However, RNA visualization approaches in whole organisms are notably underdeveloped. Here, we establish our RNA tagging and imaging platform Riboglow-FLIM for complex cellular imaging applications by systematically evaluating FLIM capabilities. We use adherent mammalian cells as models for RNA visualization. Additional complexity of analyzing RNAs in whole mammalian animals is achieved by injecting these cells into a zebrafish embryo system for cell-by-cell analysis in this model of multicellularity. We first evaluate all variable elements of Riboglow-FLIM quantitatively before assessing optimal use in whole animals. In this way, we demonstrate that a model noncoding RNA can be detected robustly and quantitatively inside live zebrafish embryos using a far-red Cy5-based variant of the Riboglow platform. We can clearly resolve cell-to-cell heterogeneity of different RNA populations by this methodology, promising applicability in diverse fields.

Understanding the Molecular Basis for Homodimer Formation of the Pneumococcal Endolysin Cpl-1.

The rise of multi-drug-resistant bacteria that cannot be treated with traditional antibiotics has prompted the search for alternatives to combat bacterial infections. Endolysins, which are bacteriophage-derived peptidoglycan hydrolases, are attractive tools in this fight. Several studies have already demonstrated the efficacy of endolysins in targeting bacterial infections. Endolysins encoded by bacteriophages that infect Gram-positive bacteria typically possess an N-terminal catalytic domain and a C-terminal cell-wall binding domain (CWBD). In this study, we have uncovered the molecular mechanisms that underlie formation of a homodimer of Cpl-1, an endolysin that targets Streptococcus pneumoniae. Here, we use site-directed mutagenesis, analytical size exclusion chromatography, and analytical ultracentrifugation to disprove a previous suggestion that three residues at the N-terminus of the CWBD are involved in the formation of a Cpl-1 dimer in the presence of choline in solution. We conclusively show that the C-terminal tail region of Cpl-1 is involved in formation of the dimer. Alanine scanning mutagenesis generated various tail mutant constructs that allowed identification of key residues that mediate Cpl-1 dimer formation. Finally, our results allowed identification of a consensus sequence (FxxEPDGLIT) required for choline-dependent dimer formation─a sequence that occurs frequently in pneumococcal autolysins and endolysins. These findings shed light on the mechanisms of Cpl-1 and related enzymes and can be used to inform future engineering efforts for their therapeutic development against S. pneumoniae.

Twisted Carotenoids Do Not Support Efficient Intramolecular Singlet Fission in the Orange Carotenoid Protein.

Singlet exciton fission is the spin-allowed generation of two triplet electronic excited states from a singlet state. Intramolecular singlet fission has been suggested to occur on individual carotenoid molecules within protein complexes provided that the conjugated backbone is twisted out of plane. However, this hypothesis has been forwarded only in protein complexes containing multiple carotenoids and bacteriochlorophylls in close contact. To test the hypothesis on twisted carotenoids in a "minimal" one-carotenoid system, we study the orange carotenoid protein (OCP). OCP exists in two forms: in its orange form (OCPo), the single bound carotenoid is twisted, whereas in its red form (OCPr), the carotenoid is planar. To enable room-temperature spectroscopy on canthaxanthin-binding OCPo and OCPr without laser-induced photoconversion, we trap them in a trehalose glass. Using transient absorption spectroscopy, we show that there is no evidence of long-lived triplet generation through intramolecular singlet fission despite the canthaxanthin twist in OCPo.

Jaw Reduction Surgery.

Facial feminization surgery (FFS) combines a series of facial bone and soft tissue surgeries to feminize the masculine appearance of the face in a transgender female patient. Jaw reduction surgery is an extremely critical component of FFS and is generally performed in combination with genioplasty. Our technique of jaw reduction involves sagittal resection of the mandible from the angle of the jaw to the mental nerve region. This creates a smooth transition from the ramus to the chin and also retains the integrity of the inner portion of the mandible. We discuss our techniques of jaw reduction surgery in this article.