Comparative genomic analysis of Microcystis strain diversity using conserved marker genes.

Microcystis-dominated cyanobacterial harmful algal blooms (cyanoHABs) have a global impact on freshwater environments, affecting both wildlife and human health. Microcystis diversity and function in field samples and laboratory cultures can be determined by sequencing whole genomes of cultured isolates or natural populations, but these methods remain computationally and financially expensive. Amplicon sequencing of marker genes is a lower cost and higher throughput alternative to characterize strain composition and diversity in mixed samples. However, the selection of appropriate marker gene region(s) and primers requires prior understanding of the relationship between single gene genotype, whole genome content, and phenotype. To identify phylogenetic markers of Microcystis strain diversity, we compared phylogenetic trees built from each of 2,351 individual core genes to an established phylogeny and assessed the ability of these core genes to predict whole genome content and bioactive compound genotypes. We identified single-copy core genes better able to resolve Microcystis phylogenies than previously identified marker genes. We developed primers suitable for current Illumina-based amplicon sequencing with near-complete coverage of available Microcystis genomes and demonstrate that they outperform existing options for assessing Microcystis strain composition. Results showed that genetic markers can be used to infer Microcystis gene content and phenotypes such as potential production of bioactive compounds , although marker performance varies by bioactive compound gene and sequence similarity. Finally, we demonstrate that these markers can be used to characterize the Microcystis strain composition of laboratory or field samples like those collected for surveillance and modeling of Microcystis-dominated cyanobacterial harmful algal blooms.

Retrograde cricopharyngeus dysfunction: How does the inability to burp affect daily life?

BACKGROUND: Retrograde cricopharyngeus dysfunction (R-CPD), a condition first detailed in 1987 and termed in 2019, refers to the cricopharyngeal muscle's inability to relax to allow the retrograde passage of gas. Limited research exists on the fundamental characteristics of this condition, including its impact on one's life. The purpose of this study is to characterize R-CPD and how the inability to burp affects the social lives of people who suffer from it. METHODS: A Qualtrics survey was distributed on the subreddit "r/noburp," a community of 26,000 individuals sharing information about R-CPD. Adults aged 18-89 experiencing R-CPD symptoms were invited to participate. Participants reported on their experiences with R-CPD and its effects on social life on a 4-point Likert scale (1 = strongly disagree to 4 = strongly agree). Data was analyzed using descriptive statistics. KEY RESULTS: Among the 199 respondents, the mean age was 30.9, and gender identity was 74%/25% female/male. 99% reported inability to burp, 98% reported abdominal bloating, 93% reported socially awkward gurgling noises, 89% reported excessive flatulence, and 55% reported difficulty vomiting. Only half discussed their symptoms with their primary care provider (PCP), and 90% disagreed with receiving adequate help. Average Likert scores indicated embarrassment (3.4), anxiety/depression (3.1), negative impact on relationships (2.6), and work disruption (2.7) due to R-CPD. CONCLUSIONS & INFERENCES: R-CPD is unfamiliar to many healthcare providers, leaving patients underserved. It not only affects daily life but also personal and professional relationships. Raising awareness by understanding disease basic features may increase diagnosis and treatment rates, improving quality of life.

The Western Lake Erie culture collection: A promising resource for evaluating the physiological and genetic diversity of Microcystis and its associated microbiome.

Cyanobacterial harmful algal blooms (cyanoHABs) dominated by Microcystis spp. have significant public health and economic implications in freshwater bodies around the world. These blooms are capable of producing a variety of cyanotoxins, including microcystins, that affect fishing and tourism industries, human and environmental health, and access to drinking water. In this study, we isolated and sequenced the genomes of 21 primarily unialgal Microcystis cultures collected from western Lake Erie between 2017 and 2019. While some cultures isolated in different years have a high degree of genetic similarity (genomic Average Nucleotide Identity >99%), genomic data show that these cultures also represent much of the breadth of known Microcystis diversity in natural populations. Only five isolates contained all the genes required for microcystin biosynthesis while two isolates contained a previously described partial mcy operon. Microcystin production within cultures was also assessed using Enzyme-Linked Immunosorbent Assay (ELISA) and supported genomic results with high concentrations (up to 900 µg L⁻¹) in cultures with complete mcy operons and no or low toxin detected otherwise. These xenic cultures also contained a substantial diversity of bacteria associated with Microcystis, which has become increasingly recognized as an essential component of cyanoHAB community dynamics. These results highlight the genomic diversity among Microcystis strains and associated bacteria in Lake Erie, and their potential impacts on bloom development, toxin production, and toxin degradation. This culture collection significantly increases the availability of environmentally relevant Microcystis strains from temperate North America.

Chalazion: racial risk factors for formation, recurrence, and surgical intervention.

OBJECTIVE: An association between race and formation of chalazion has yet to be objectively established. This study investigates race as a risk factor for chalazion and chalazion surgery. Understanding racial risk factors in formation of chalazion, recurrent chalazion, and chalazion requiring surgery (often with general anesthesia in children) informs decisions regarding eyelid hygiene, early topical medical therapy, and aggressiveness with oral antibiotic therapy for coexisting conditions such as blepharitis. METHODS: Demographic data was collected for all pediatric visits to the University of Wisconsin-Madison ophthalmology department from 2012-2019. Retrospective chart review was performed for the subset with chalazion. RESULTS: Of 28 433 minors, 584 had 1088 chalazia, a 2% overall rate. Chalazion was seen in 1.8% of non-Hispanic/Latino participants and 3.8% of Hispanic/Latino participants (p value <0.0001). Chalazion was seen in 1.7% of white participants, compared to 4.3% of American Indian or Alaska Native participants (p value <0.0001) and 4.0% of Asian participants (p value <0.0001). More than one chalazion was recorded in 31% of subjects without coexisting meibomian gland disease, blepharitis, or marginal keratitis, and in 56% (p < 0.0001) with one of these conditions. Repeated diagnoses of chalazion on separate encounters were seen in 17% without these conditions and in 33% (p < 0.0001) with one of these conditions. CONCLUSION: Hispanic/Latino, American Indian, and Asian participants developed chalazion at a rate higher than other racial/ethnic groups, whereas patients with meibomian gland disease or blepharitis are especially at risk for developing multiple chalazia on separate encounters. No group was more likely to require surgical intervention than any other.

Aesthetic Eyelid Measurements of "Beautiful People": Gender Differences and Application for Thyroid Eye Disease Patients.

There remains a paucity of studies investigating measurements of periocular structures of people popularly seen as "beautiful." Such measurements may be helpful in establishing postoperative goals and measuring aesthetic outcomes. This study (1) identifies aesthetic measurements of the periocular structures in idealized celebrities, (2) determines gender differences in such measurements, and (3) compares these measurements to patients who underwent surgical repair of upper eyelid retraction associated with thyroid eye disease. METHODS: Digital analysis of 38 celebrity photographs in People's "Most Beautiful People" and "Sexiest Man Alive" was performed to measure image-derived (denoted with an "i") margin reflex distance (iMRD1), tarsal platform show (iTPS), brow fat span (iBFS), and iTPS:iBFS ratio. The same analysis was used for 35 women who underwent surgical repair for thyroid eye disease-related upper eyelid retraction. RESULTS: Significant gender differences (P < 0.05) were observed in celebrity metrics, with women having higher upper eyelids (longer iMRD1) (3.30 mm versus 2.50 mm), longer iTPS measurements (3.90 mm versus 2.50 mm), and larger iTPS:iBFS values (0.31 versus 0.20). Postoperative thyroid eye disease patients had significantly higher upper eyelids (longer iMRD1s) (4.80 mm versus 3.30 mm), longer iTPS (5.10 mm versus 3.90 mm), and larger iTPS:iBFS (0.37 versus 0.31) than celebrities. CONCLUSIONS: There are significant gender differences in the periocular metrics of "beautiful people." Optimal aesthetic outcomes may be more effectively obtained by achieving a preferred range of ratios than by relying on independent measurements. Although aesthetic outcomes are multi-factorial, measurements of "beautiful" people provide helpful guidelines to gauge aesthetic outcomes.

The genetic and ecophysiological diversity of Microcystis.

Microcystis is a cyanobacterium that forms toxic blooms in freshwater ecosystems around the world. Biological variation among taxa within the genus is apparent through genetic and phenotypic differences between strains and via the spatial and temporal distribution of strains in the environment, and this fine-scale diversity exerts strong influence over bloom toxicity. Yet we do not know how varying traits of Microcystis strains govern their environmental distribution, the tradeoffs and links between these traits, or how they are encoded at the genomic level. Here we synthesize current knowledge on the importance of diversity within Microcystis and on the genes and traits that likely underpin ecological differentiation of taxa. We briefly review spatial and environmental patterns of Microcystis diversity in the field and genetic evidence for cohesive groups within Microcystis. We then compile data on strain-level diversity regarding growth responses to environmental conditions and explore evidence for variation of community interactions across Microcystis strains. Potential links and tradeoffs between traits are identified and discussed. The resulting picture, while incomplete, highlights key knowledge gaps that need to be filled to enable new models for predicting strain-level dynamics, which influence the development, toxicity and cosmopolitan nature of Microcystis blooms.

Perturbation-induced fast drifts in finger enslaving.

We explored changes in finger forces and in an index of unintentional finger force production (enslaving) under a variety of visual feedback conditions and positional finger perturbations. In particular, we tested a hypothesis that enslaving would show a consistent increase with time at characteristic times of about 1-2 s. Young healthy subjects performed accurate force production tasks under visual feedback on the total force of the instructed fingers (index and ring) or enslaved fingers (middle and little). Finger feedback was covertly alternated between master and enslaved fingers in a random fashion. The feedback could be presented over the first 5 s of the trial only or over the whole trial duration (21 s). After 5 s, the fingers were lifted by 1 cm, and after 15 s, the fingers were lowered to the initial position. The force of the instructed fingers drifted toward lower magnitudes in all conditions except the one with continuous feedback on that force. The force of enslaved fingers showed variable behavior across conditions. In all conditions, the index of enslaving showed a consistent increase with the time constant varying between 1 and 3 s. We interpret the results as pointing at the spread of excitation to enslaved fingers (possibly, in the cortical M1 areas). The relatively fast changes in enslaving under positional finger perturbations suggest that quick changes of the input into M1 from pre-M1 areas can accelerate the hypothesized spread of cortical excitation.

To Dereplicate or Not To Dereplicate?

Metagenome-assembled genomes (MAGs) expand our understanding of microbial diversity, evolution, and ecology. Concerns have been raised on how sequencing, assembly, binning, and quality assessment tools may result in MAGs that do not reflect single populations in nature. Here, we reflect on another issue, i.e., how to handle highly similar MAGs assembled from independent data sets. Obtaining multiple genomic representatives for a species is highly valuable, as it allows for population genomic analyses; however, when retaining genomes of closely related populations, it complicates MAG quality assessment and abundance inferences. We show that (i) published data sets contain a large fraction of MAGs sharing >99% average nucleotide identity, (ii) different software packages and parameters used to resolve this redundancy remove very different numbers of MAGs, and (iii) the removal of closely related genomes leads to losses of population-specific auxiliary genes. Finally, we highlight some approaches that can infer strain-specific dynamics across a sample series without dereplication.

Genome evolution and host-microbiome shifts correspond with intraspecific niche divergence within harmful algal bloom-forming Microcystis aeruginosa.

Intraspecific niche divergence is an important driver of species range, population abundance and impacts on ecosystem functions. Genetic changes are the primary focus when studying intraspecific divergence; however, the role of ecological interactions, particularly host-microbiome symbioses, is receiving increased attention. The relative importance of these evolutionary and ecological mechanisms has seen only limited evaluation. To address this question, we used Microcystis aeruginosa, the globally distributed cyanobacterium that dominates freshwater harmful algal blooms. These blooms have been increasing in occurrence and intensity worldwide, causing major economic and ecological damages. We evaluated 46 isolates of M. aeruginosa and their microbiomes, collected from 14 lakes in Michigan, USA, that vary over 20-fold in phosphorus levels, the primary limiting nutrient in freshwater systems. Genomes of M. aeruginosa diverged along this phosphorus gradient in genomic architecture and protein functions. Fitness in low-phosphorus lakes corresponded with additional shifts within M. aeruginosa including genome-wide reductions in nitrogen use, an expansion of phosphorus assimilation genes and an alternative life history strategy of nonclonal colony formation. In addition to host shifts, despite culturing in common-garden conditions, host-microbiomes diverged along the gradient in taxonomy, but converged in function with evidence of metabolic interdependence between the host and its microbiome. Divergence corresponded with a physiological trade-off between fitness in low-phosphorus environments and growth rate in phosphorus-rich conditions. Co-occurrence of genotypes adapted to different nutrient environments in phosphorus-rich lakes may have critical implications for understanding how M. aeruginosa blooms persist after initial nutrient depletion. Ultimately, we demonstrate that the intertwined effects of genome evolution, host life history strategy and ecological interactions between a host and its microbiome correspond with an intraspecific niche shift with important implications for whole ecosystem function.

Effect of iris show on perceived upper eyelid height.

OBJECTIVE: To introduce "iris show," the amount of visible iris tissue between the superior pupil border and the upper eyelid margin, to evaluate the effect of iris show on perceived upper eyelid height, and to discuss potential nonsurgical treatment options for mild blepharoptosis. METHODS: Participants completed a survey containing 4 subject photographs. These photographs depicted images of varying iris colouration (blue, green, light brown, and dark brown) with identical upper eyelid marginal reflex distance (MRD1) values, but asymmetric pupil size/amount of visible iris show. Study participants were asked to select the eyelid that appeared "droopier," or choose "same height." Statistical analyses used 1-tailed and 2-tailed t tests. RESULTS: 390 participants completed the survey. In photographs of blue and green irides, both eyelids had equal MRD1s, but the eyelid with less iris show was perceived as more ptotic (p = 0.002 and 0.03, respectively). In patients with dark brown irides, eyelid heights were perceived as identical despite differences in iris show (p = 0.002). CONCLUSIONS: Decreased iris show corresponds to perceived lowering of the upper eyelid in light-coloured irides (e.g., blue and green), but may be less impactful in brown and/or dark brown irides where the iris tissue is less distinguishable from the pupil. Topical instillation of apraclonidine may represent a nonsurgical option for treatment of mild blepharoptosis in patients with light irides as it both elevates the upper eyelid margin and induces miosis, resulting in an increase in iris show and corresponding enhanced perception of upper eyelid elevation.

Rethinking Our Definition of Postoperative Success: A Comparative Analysis of Three Upper Eyelid Retraction Repair Techniques Using Novel Metrics to Capture Functional and Aesthetic Outcomes.

PURPOSE: To compare 3 upper eyelid retraction repair techniques and introduce novel metrics, which enhance the analysis of postoperative aesthetic outcomes. METHODS: Retrospective review with Image J 1.48 digital analysis of patients who underwent repair of thyroid-related upper eyelid retraction at the University of Iowa from 1996 to 2014 via 1 of 3 surgical techniques, septum-opening levator recession with Muellerectomy, modified septum-preserving levator recession with Muellerectomy, and modified septum-preserving full-thickness blepharotomy, was conducted. Photographs were obtained preoperatively, 3 to 6 months postoperatively, and at last follow up (>6 months) and evaluated by digital image analysis (denoted by "i"). Outcome measures assessed were marginal reflex distance (iMRD1), temporal-to-nasal ratio, tarsal platform show (iTPS), pupil to visible eyelid crease, brow fat span (iBFS), tarsal platform show to brow fat span ratio (iTPS:iBFS), and tarsal platform show minimizing power (iTPS-minimizing power). RESULTS: A total of 121 eyelids (28 septum-opening levator recession with Muellerectomy, 66 septum-preserving levator recession with Muellerectomy, and 27 septum-preserving full-thickness blepharotomy) from 74 patients were evaluated with a mean follow up of 24.2 months. There were no statistically significant differences between techniques in terms of iMRD1 or temporal-to-nasal ratio reduction at either time point (intertechnique p values of 0.17 to >0.99). The percentage of eyelids from subjects undergoing bilateral intervention that achieved a final iMRD1 between 2.50 mm and 4.50 mm was similar (intertechnique p value of 0.23), with no difference regarding the number of subjects demonstrating iMRD1 symmetry within 1 mm (intertechnique p value of 0.15). Though iTPS elongation was greater at 3 to 6 months with septum-opening compared with the combined septum-preserving techniques (p value of 0.04), this difference was not maintained at final follow up (p value of >0.99). There was no difference in terms of iTPS symmetry at time of final follow up (intertechnique p value of 0.69). The pupil to visible eyelid crease was unchanged in all techniques (p values >0.99). Mean changes in iBFS at final follow up were -1.27 mm, -0.44 mm, and +0.55 mm for septum-opening levator recession with Muellerectomy, septum-preserving levator recession with Muellerectomy, and septum-preserving full-thickness blepharotomy (p values of 0.01, 0.49, and >0.99, respectively). Mean iTPS:iBFS ratios at final follow up were not statistically different between techniques (intertechnique p value of 0.10) and no difference in symmetry was demonstrated (intertechnique p value of 0.47). Median values for iTPS-minimizing power were: -0.83, -0.93, and -1.01 for septum-opening levator recession with Muellerectomy, septum-preserving levator recession with Muellerectomy, and septum-preserving full-thickness blepharotomy, respectively (intertechnique p value of 0.54). CONCLUSIONS: Each technique appropriately lowered the eyelid and improved contour without intertechnique variability. Septum-preserving techniques demonstrated less iTPS elongation initially, but this difference was not maintained. The visible eyelid crease height (pupil to visible eyelid crease) remained stable in all techniques, indicating that the iTPS elongation seen with each technique was secondary to reduction in iMRD1 and the iBFS reduction seen with septum-opening levator recession with Muellerectomy was due to brow descent. No intertechnique differences in the amount of iTPS elongation relative to iMRD1 reduction (i.e., the novel iTPS-minimizing power) were seen. Given that each procedure evaluated yielded similar results, technique selection may be guided by surgeon experience and preference.

Optical Coherence Tomography-Assisted Limbal Dermoid Removal.

This report and accompanying video show the novel use of intraoperative optical coherence tomography (OCT) in the excision of a limbal dermoid. Examining for residual opaque tissue in the cornea accompanied by OCT imaging is a useful technique to confirm complete excision of the lesion. [J Pediatr Ophthalmol Strabismus. 2017;54:e58-e59.].

A natural hybrid of a Bacillus thuringiensis Cry2A toxin implicates Domain I in specificity determination.

A PCR-RFLP method was used to identify cry2A toxin genes in a collection of 300 strains of Bacillus thuringiensis. From 81 genes identified, the vast majority appeared to be cry2Aa or cry2Ab, however three showed a different pattern and were subsequently cloned and sequenced. The gene cloned from strain HD395 was named cry2Ba2. Since the proteins encoded by the genes cloned from LS5115-3 and DS415 shared >95% sequence identity with existing toxins their genes were named cry2Aa17 and cry2Ab29 respectively by the toxin nomenclature committee. Despite this overall similarity these two toxins resembled natural hybrids, with Cry2Ab29 resembling Cry2Ab for the majority of the protein but then showing identity to Cry2Aa for the last 66 amino acids. For Cry2Aa17, Domains II and III most closely resembled Cry2Aa (99% identity) whilst Domain I was identical to that of Cry2Ab. The toxicity of the recombinant toxins was tested against Aedes aegypti and Spodoptera exigua, and it was found that the toxicity profile of Cry2Aa17 more closely matched the profile of Cry2Ab than that of Cry2Aa, thus implicating Domain I in specificity determination. This association of Domain I with toxicity was confirmed when hybrids were made between Cry2Aa and Cry2Ab.