PeerJ Preprints: Ophthalmologyhttps://peerj.com/preprints/index.atom?journal=peerj&subject=5800Ophthalmology articles published in PeerJ PreprintsSeven myths on crowding and peripheral visionhttps://peerj.com/preprints/273532019-12-062019-12-06Hans Strasburger
Crowding has become a hot topic in vision research and some fundamentals are now widely agreed upon. For the classical crowding task, one would likely agree with the following statements. (1) Bouma’s law can, succinctly and unequivocally, be stated as saying that critical distance for crowding is about half the target’s eccentricity. (2) Crowding is predominantly a peripheral phenomenon. (3) Peripheral vision extends to at most 90° eccentricity. (4) Resolution threshold (the minimal angle of resolution, MAR) increases strongly and linearly with eccentricity. Crowding increases at an even steeper rate. (5) Crowding is asymmetric as Bouma has shown. For that inner-outer asymmetry, the peripheral flanker has more effect. (6) Critical crowding distance corresponds to a constant cortical distance in primary visual areas like V1. (7) Except for Bouma’s seminal paper in 1970, crowding research mostly became prominent starting in the 2000s. I propose the answer is ‘not really’ or ‘not quite’ to these assertions. So should we care? I think we should, before we write the textbook chapters for the next generation.
Crowding has become a hot topic in vision research and some fundamentals are now widely agreed upon. For the classical crowding task, one would likely agree with the following statements. (1) Bouma’s law can, succinctly and unequivocally, be stated as saying that critical distance for crowding is about half the target’s eccentricity. (2) Crowding is predominantly a peripheral phenomenon. (3) Peripheral vision extends to at most 90° eccentricity. (4) Resolution threshold (the minimal angle of resolution, MAR) increases strongly and linearly with eccentricity. Crowding increases at an even steeper rate. (5) Crowding is asymmetric as Bouma has shown. For that inner-outer asymmetry, the peripheral flanker has more effect. (6) Critical crowding distance corresponds to a constant cortical distance in primary visual areas like V1. (7) Except for Bouma’s seminal paper in 1970, crowding research mostly became prominent starting in the 2000s. I propose the answer is ‘not really’ or ‘not quite’ to these assertions. So should we care? I think we should, before we write the textbook chapters for the next generation.The key genes involved in herpes simplex virus-1 corneal infection-induced acute hepatitishttps://peerj.com/preprints/277242019-05-132019-05-13Kai HuJinlong LiXianwen Yuan
Background: Viral keratitis is mainly induced by herpes simplex virus (HSV). HSV-1 infection-induced acute hepatitis associates with immunodeficiency. Related biomarkers have not been systemically identified till now. This study was designed to explore the molecular mechanisms and potential biomarkers of HSV-1 infection-induced acute hepatitis.
Methods: Microarray dataset GSE35943, including the liver tissues infected by HSV-1 (1, 3, 5, and 7 days post infection) and the corresponding control tissues, was extracted from Gene Expression Omnibus database. The differentially expressed genes (DEGs) were identified using and were clustered using time series expression analysis. DEG-associated KEGG pathways were called using online DAVID tool. Using Cytoscape software, protein-protein interaction (PPI) network was built and significant network modules were identified.
Results: A total of 2909 DEGs grouping into 3 clusters with similar gene expression profiles were obtained. The DEGs were involved in immune-associated functional terms and pathways like natural killer cell mediated cytotoxicity and antigen processing and presentation. DEGs including PIK3R1, PIK3CD, PLCG2, PTPN6, LCK, RAC2, and PLK1 had higher degrees in the PPI network and 8 significant modules
Conclusion: PIK3R1, PIK3CD, PLCG2, PTPN6, LCK, RAC2 and PLK1 were identified to be associated with HSV-1 corneal infection-induced hepatitis, and might be potential clinical biomarkers for the diagnosis of HSV-1-induced hepatitis.
Background: Viral keratitis is mainly induced by herpes simplex virus (HSV). HSV-1 infection-induced acute hepatitis associates with immunodeficiency. Related biomarkers have not been systemically identified till now. This study was designed to explore the molecular mechanisms and potential biomarkers of HSV-1 infection-induced acute hepatitis.Methods: Microarray dataset GSE35943, including the liver tissues infected by HSV-1 (1, 3, 5, and 7 days post infection) and the corresponding control tissues, was extracted from Gene Expression Omnibus database. The differentially expressed genes (DEGs) were identified using and were clustered using time series expression analysis. DEG-associated KEGG pathways were called using online DAVID tool. Using Cytoscape software, protein-protein interaction (PPI) network was built and significant network modules were identified.Results: A total of 2909 DEGs grouping into 3 clusters with similar gene expression profiles were obtained. The DEGs were involved in immune-associated functional terms and pathways like natural killer cell mediated cytotoxicity and antigen processing and presentation. DEGs including PIK3R1, PIK3CD, PLCG2, PTPN6, LCK, RAC2, and PLK1 had higher degrees in the PPI network and 8 significant modulesConclusion: PIK3R1, PIK3CD, PLCG2, PTPN6, LCK, RAC2 and PLK1 were identified to be associated with HSV-1 corneal infection-induced hepatitis, and might be potential clinical biomarkers for the diagnosis of HSV-1-induced hepatitis.Cortical modulation of pupillary function: Systematic reviewhttps://peerj.com/preprints/275102019-01-312019-01-31Costanza PeinkhoferGitte Moos KnudsenRita MorettiDaniel Kondziella
Background. The pupillary light reflex is the main mechanism that regulates the pupillary diameter; it is controlled by the autonomic system and mediated by subcortical pathways. In addition, cognitive and emotional processes influence pupillary function due to input from cortical innervation, but the exact circuits remain poorly understood. We performed a systematic review to evaluate the mechanisms behind pupillary changes associated with cognitive efforts and processing of emotions and to investigate the cerebral areas involved in cortical modulation of the pupillary light reflex.
Methodology. We searched multiple databases until November 2018 for studies on cortical modulation of pupillary function in humans and non-human primates. Of 8808 papers screened, 252 studies were included.
Results. Most investigators focused on pupillary dilatation as an index of cognitive and emotional processing, evaluating how changes in pupillary diameter reflect levels of attention and arousal. Only few tried to correlate specific cerebral areas to pupillary changes, using either cortical activation models (employing micro-stimulation of cortical structures in non-human primates) or cortical lesion models (e.g. investigating patients with stroke and damage to salient cortical and/or subcortical areas). Results suggest involvement of several cortical regions, including the insular cortex, the frontal eye field and the prefrontal cortex, and of subcortical structures such as the locus coeruleus and the superior colliculus.
Conclusions. Pupillary dilatation occurs with many kinds of mental or emotional processes, following sympathetic activation or parasympathetic inhibition. This phenomenon is controlled by several subcortical and cortical structures that are directly or indirectly connected to the brainstem pupillary innervation system.
Background. The pupillary light reflex is the main mechanism that regulates the pupillary diameter; it is controlled by the autonomic system and mediated by subcortical pathways. In addition, cognitive and emotional processes influence pupillary function due to input from cortical innervation, but the exact circuits remain poorly understood. We performed a systematic review to evaluate the mechanisms behind pupillary changes associated with cognitive efforts and processing of emotions and to investigate the cerebral areas involved in cortical modulation of the pupillary light reflex.Methodology. We searched multiple databases until November 2018 for studies on cortical modulation of pupillary function in humans and non-human primates. Of 8808 papers screened, 252 studies were included.Results. Most investigators focused on pupillary dilatation as an index of cognitive and emotional processing, evaluating how changes in pupillary diameter reflect levels of attention and arousal. Only few tried to correlate specific cerebral areas to pupillary changes, using either cortical activation models (employing micro-stimulation of cortical structures in non-human primates) or cortical lesion models (e.g. investigating patients with stroke and damage to salient cortical and/or subcortical areas). Results suggest involvement of several cortical regions, including the insular cortex, the frontal eye field and the prefrontal cortex, and of subcortical structures such as the locus coeruleus and the superior colliculus.Conclusions. Pupillary dilatation occurs with many kinds of mental or emotional processes, following sympathetic activation or parasympathetic inhibition. This phenomenon is controlled by several subcortical and cortical structures that are directly or indirectly connected to the brainstem pupillary innervation system.Important metabolites in maintaining folic acid, homocysteine and polyamine metabolism associated with ranibizumab treatment in cultured Human Tenon’s Fibroblasthttps://peerj.com/preprints/274922019-01-172019-01-17Siti Munirah Md NohSiti Hamimah Sheikh Abdul KadirSushil Kumar Vasudevan
Anti-fibrotic properties of ranibizumab have been well documented. As an antagonist to Vascular Endothelial Growth Factor (VEGF), ranibizumab works by binding and neutralizes all active VEGF, thus limits the progressive cell growth and proliferation. Its application in ocular diseases has shown remarkable desired effects, however to date its anti-fibrotic mechanism is not well understood. In this study, we identified metabolic changes in ranibizumab-treated Human Tenos’s fibroblast (HTF). Cultured HTFs were treated for48 hours with 0.5 mg/ml of ranibizumab and 0.5 mg/ml control IgG antibody which serves as a negative control. Samples from each group were injected into Agilent 6520 Q-TOF Liquid Chromatography/ Mass Spectrometer (LC/MS) System to establish the metabolite expression in both ranibizumab treated cells and control group. Data obtained was analysed using Agilent Mass Hunter Qualitative Analysis software to identify the most regulated metabolite following ranibizumab treatment. At statistical analysis of p-value < 0.01 with the cut off value of two-fold change, 31 identified metabolites were found to be significantly up-regulated in ranibizumab-treated group, with 6 of the mostly up-regulated have insignificant role in fibroblast’s cell cycle and wound healing regulations Meanwhile, 121 identified metabolites were down-regulated with seven of the mostly down-regulated are significantly involved in cell cycle and proliferation. Our findings demonstrated that ranibizumab abrogates the tissue scarring process and wound healing formation by regulating the expression of metabolites associated with fibrotic activity. In particular, we found that vitamin Bs are important in maintaining normal folic acid cycle, nucleotide synthesis, homocysteine and spermidine metabolism. This study provides an insight of ranibizumab mechanism of actions on HTFs from the perspective of metabolomics.
Anti-fibrotic properties of ranibizumab have been well documented. As an antagonist to Vascular Endothelial Growth Factor (VEGF), ranibizumab works by binding and neutralizes all active VEGF, thus limits the progressive cell growth and proliferation. Its application in ocular diseases has shown remarkable desired effects, however to date its anti-fibrotic mechanism is not well understood. In this study, we identified metabolic changes in ranibizumab-treated Human Tenos’s fibroblast (HTF). Cultured HTFs were treated for48 hours with 0.5 mg/ml of ranibizumab and 0.5 mg/ml control IgG antibody which serves as a negative control. Samples from each group were injected into Agilent 6520 Q-TOF Liquid Chromatography/ Mass Spectrometer (LC/MS) System to establish the metabolite expression in both ranibizumab treated cells and control group. Data obtained was analysed using Agilent Mass Hunter Qualitative Analysis software to identify the most regulated metabolite following ranibizumab treatment. At statistical analysis of p-value < 0.01 with the cut off value of two-fold change, 31 identified metabolites were found to be significantly up-regulated in ranibizumab-treated group, with 6 of the mostly up-regulated have insignificant role in fibroblast’s cell cycle and wound healing regulations Meanwhile, 121 identified metabolites were down-regulated with seven of the mostly down-regulated are significantly involved in cell cycle and proliferation. Our findings demonstrated that ranibizumab abrogates the tissue scarring process and wound healing formation by regulating the expression of metabolites associated with fibrotic activity. In particular, we found that vitamin Bs are important in maintaining normal folic acid cycle, nucleotide synthesis, homocysteine and spermidine metabolism. This study provides an insight of ranibizumab mechanism of actions on HTFs from the perspective of metabolomics.Seven myths on crowdinghttps://peerj.com/preprints/272502018-10-032018-10-03Hans Strasburger
Crowding research has become a hotbed of vision research and some fundamentals are now widely agreed upon. You would agree with the following statements – wouldn’t you? 1) Bouma’s Law can be sensibly stated as saying that ‘critical distance for crowding is about half the target’s eccentricity’. 2) Crowding is a peripheral phenomenon. 3) Crowding increases drastically with eccentricity (as does the minimal angle of resolution, MAR). 4) Crowding asymmetry: For the nasal-temporal asymmetry of crowding, Bouma’s (1970) paper is the one to cite. 5) The more peripheral flanker is the more important one in crowding. 6) Critical crowding distance corresponds to a constant cortical distance in V1. 7) Except for Bouma (1970), serious crowding research pretty much started in the noughties. I propose the answer is ‘no!’ to all these questions. So should we care? I think we should, before we write the textbooks for the next generation.
Crowding research has become a hotbed of vision research and some fundamentals are now widely agreed upon. You would agree with the following statements – wouldn’t you? 1) Bouma’s Law can be sensibly stated as saying that ‘critical distance for crowding is about half the target’s eccentricity’. 2) Crowding is a peripheral phenomenon. 3) Crowding increases drastically with eccentricity (as does the minimal angle of resolution, MAR). 4) Crowding asymmetry: For the nasal-temporal asymmetry of crowding, Bouma’s (1970) paper is the one to cite. 5) The more peripheral flanker is the more important one in crowding. 6) Critical crowding distance corresponds to a constant cortical distance in V1. 7) Except for Bouma (1970), serious crowding research pretty much started in the noughties. I propose the answer is ‘no!’ to all these questions. So should we care? I think we should, before we write the textbooks for the next generation.The effect of postoperative oral antibiotic therapy on the incidence of postoperative endophthalmitis after phacoemulsification surgery in dogs. 320 eyes (1997-2006)https://peerj.com/preprints/270912018-08-042018-08-04Amanda T. CorrDaniel A. Ward
Purpose. To assess the effectiveness of postoperative administration of oral antibiotics at reducing the incidence of endophthalmitis following phacoemulsification cataract extraction in dogs.
Methods. Medical records of the University of Tennessee College of Veterinary Medicine were reviewed for cases having undergone phacoemulsification and divided according to whether or not they had received oral antibiotics postoperatively. Records were then evaluated for a diagnosis of endophthalmitis and incidence rates between the group receiving postoperative oral antibiotics and the group not receiving postoperative oral antibiotics were compared.
Results. A total of 185 patients (320 eyes) were identified by the search. 113 patients (197 eyes) were treated with oral antibiotics postoperatively. 72 patients (123 eyes) were not treated with oral antibiotics postoperatively. Two cases of endophthalmitis were identified, with 1 in each group (P>0.05, Fisher’s exact test).
Conclusions. The overall incidence of endophthalmitis in this study was 0.63%. The rate of postphacoemulsification endophthalmitis was unaffected by the postoperative administration of oral antibiotics.
Purpose. To assess the effectiveness of postoperative administration of oral antibiotics at reducing the incidence of endophthalmitis following phacoemulsification cataract extraction in dogs.Methods. Medical records of the University of Tennessee College of Veterinary Medicine were reviewed for cases having undergone phacoemulsification and divided according to whether or not they had received oral antibiotics postoperatively. Records were then evaluated for a diagnosis of endophthalmitis and incidence rates between the group receiving postoperative oral antibiotics and the group not receiving postoperative oral antibiotics were compared.Results. A total of 185 patients (320 eyes) were identified by the search. 113 patients (197 eyes) were treated with oral antibiotics postoperatively. 72 patients (123 eyes) were not treated with oral antibiotics postoperatively. Two cases of endophthalmitis were identified, with 1 in each group (P>0.05, Fisher’s exact test).Conclusions. The overall incidence of endophthalmitis in this study was 0.63%. The rate of postphacoemulsification endophthalmitis was unaffected by the postoperative administration of oral antibiotics.The anatomy of the foveola reinvestigatedhttps://peerj.com/preprints/265182018-02-132018-02-13Alexander V. TschulakowTheo OltrupThomas BendeSebastian SchmelzleUlrich Schraermeyer
Objective. In the foveola of the eye, photoreceptors and Müller cells with a unique morphology have been described, but little is known about their 3D structure and orientation. Considering that there is an angle-dependent change in the foveolar photoreceptor response for the same light beam, known as the Stiles Crawford Effect of the first kind (SCE I), which is still not fully understood, a detailed analysis of the anatomy of the foveolar cells might help to clarify this phenomenon. Methods. Serial semithin and ultrathin sections, and focused ion beam (FIB) tomography were -prepared from 32 foveolae from monkeys (Macaca fascicularis) and humans. Foveolae were also analyzed under the electron microscope. Serial sections and FIB analysis were then used to construct 3D models of central Müller and photoreceptor cells. In addition, we measured the transmission of collimated light under the light microscope at different angles after it had passed through human foveae from flat mounted isolated retinae. Results. In monkeys, outer segments of central foveolar cones are twice as long as those from parafoveal cones and do not run completely parallel to the incident light. Unique Müller cells are present in the central foveolae (area of 200 µm in diameter) of humans and monkeys. Light entering the fovea center, which is composed only of cones and Müller cells, at an angle of 0 degrees causes a very bright spot after passing through this area. However, when the angle of the light beam is changed to 10 degrees, less light is measured after transpasssing through the retina, the foveolar center becomes darker and the SCE-like phenomenon is directly visible. Measurements of the intensities of light transmission through the central foveola for the incident angles 0 and 10 degrees resemble the relative luminance efficiency for narrow light bundles as a function of the location where the beam enters the pupil as reported by Stiles and Crawford. The effect persisted after carefully brushing away the outer segments. Conclusion. We show that unique cones and Müller cells with light fibre-like properties are present in the center of the fovea. These unique Müller cells cause an angle dependent, SCE-like drop in the intensity of light guided through the foveola. Outer segments from the foveola cones of monkeys are not straight.
Objective. In the foveola of the eye, photoreceptors and Müller cells with a unique morphology have been described, but little is known about their 3D structure and orientation. Considering that there is an angle-dependent change in the foveolar photoreceptor response for the same light beam, known as the Stiles Crawford Effect of the first kind (SCE I), which is still not fully understood, a detailed analysis of the anatomy of the foveolar cells might help to clarify this phenomenon. Methods. Serial semithin and ultrathin sections, and focused ion beam (FIB) tomography were -prepared from 32 foveolae from monkeys (Macaca fascicularis) and humans. Foveolae were also analyzed under the electron microscope. Serial sections and FIB analysis were then used to construct 3D models of central Müller and photoreceptor cells. In addition, we measured the transmission of collimated light under the light microscope at different angles after it had passed through human foveae from flat mounted isolated retinae. Results. In monkeys, outer segments of central foveolar cones are twice as long as those from parafoveal cones and do not run completely parallel to the incident light. Unique Müller cells are present in the central foveolae (area of 200 µm in diameter) of humans and monkeys. Light entering the fovea center, which is composed only of cones and Müller cells, at an angle of 0 degrees causes a very bright spot after passing through this area. However, when the angle of the light beam is changed to 10 degrees, less light is measured after transpasssing through the retina, the foveolar center becomes darker and the SCE-like phenomenon is directly visible. Measurements of the intensities of light transmission through the central foveola for the incident angles 0 and 10 degrees resemble the relative luminance efficiency for narrow light bundles as a function of the location where the beam enters the pupil as reported by Stiles and Crawford. The effect persisted after carefully brushing away the outer segments. Conclusion. We show that unique cones and Müller cells with light fibre-like properties are present in the center of the fovea. These unique Müller cells cause an angle dependent, SCE-like drop in the intensity of light guided through the foveola. Outer segments from the foveola cones of monkeys are not straight.Histological and histochemical investigation of the compound eye of the whiteleg shrimp (Litopenaeus vannamei)https://peerj.com/preprints/34532017-12-082017-12-08Hao-Kai ChangCheng-Chung LinShih-Ling Hsuan
The compound eye is the primary visual system in crustaceans. Although the histological structure and histochemical characteristics of compound eyes of some insect and crab species are now well understood, no such studies have been undertaken in the whiteleg shrimp (Litopenaeus vannamei). In this study, eye samples from L. vannamei were fixed and paraffin sections were stained using several histochemical methods. The histological structure of each layer of the compound eye was examined and compared using different histochemical staining methods. It was found that the compound eye of L. vannamei consisted of cuticle, cornea, ommatidia, optic nerve layer, lamina ganglionaris, and medulla in an outside-in order. The cuticle of L. vannamei eyes was very thin, composed of a single epicuticle layer, as confirmed by Masson’s trichrome stain. The screening pigments produced by screening pigment cells were arranged at the junction of the ommatidia and optic nerve layer; these pigments stained differentially after different histochemical staining methods suggesting the screening pigment cells can be classified into different types. Notably, clusters of foamy glandular cells (FGCs) were observed in the optic nerve layer; these stained positively with periodic acid-Schiff and toluidine blue, and appeared blue after Masson’s trichrome stain. Immunohistochemical (IHC) staining was used to further define the origin and characteristics of FGCs. The IHC analysis showed that FGCs were positive for vimentin and synaptophysin (SYN), suggesting their neuroendocrine nature. In the medulla internalis and medulla terminalis, the neural clusters that surround the neurophil could be divided into three types by differences in morphology: the largest and the smallest cell clusters were neuron clusters and neurosecretory cells, respectively; the middle-sized cell clusters appeared SYN-positive and have not previously been described. Overall, this study is the first to provide a detailed description of the normal features of the compound eye of L. vannamei. The identification of different types of screening pigments in the ommatidia, the endocrine nature of FGcs in the optic nerve layer, and the novel neural clusters between the medulla internalis and medulla terminalis, will be important information for further study into the compound eye of L. vannamei.
The compound eye is the primary visual system in crustaceans. Although the histological structure and histochemical characteristics of compound eyes of some insect and crab species are now well understood, no such studies have been undertaken in the whiteleg shrimp (Litopenaeus vannamei). In this study, eye samples from L. vannamei were fixed and paraffin sections were stained using several histochemical methods. The histological structure of each layer of the compound eye was examined and compared using different histochemical staining methods. It was found that the compound eye of L. vannamei consisted of cuticle, cornea, ommatidia, optic nerve layer, lamina ganglionaris, and medulla in an outside-in order. The cuticle of L. vannamei eyes was very thin, composed of a single epicuticle layer, as confirmed by Masson’s trichrome stain. The screening pigments produced by screening pigment cells were arranged at the junction of the ommatidia and optic nerve layer; these pigments stained differentially after different histochemical staining methods suggesting the screening pigment cells can be classified into different types. Notably, clusters of foamy glandular cells (FGCs) were observed in the optic nerve layer; these stained positively with periodic acid-Schiff and toluidine blue, and appeared blue after Masson’s trichrome stain. Immunohistochemical (IHC) staining was used to further define the origin and characteristics of FGCs. The IHC analysis showed that FGCs were positive for vimentin and synaptophysin (SYN), suggesting their neuroendocrine nature. In the medulla internalis and medulla terminalis, the neural clusters that surround the neurophil could be divided into three types by differences in morphology: the largest and the smallest cell clusters were neuron clusters and neurosecretory cells, respectively; the middle-sized cell clusters appeared SYN-positive and have not previously been described. Overall, this study is the first to provide a detailed description of the normal features of the compound eye of L. vannamei. The identification of different types of screening pigments in the ommatidia, the endocrine nature of FGcs in the optic nerve layer, and the novel neural clusters between the medulla internalis and medulla terminalis, will be important information for further study into the compound eye of L. vannamei.Assessing vision in young children: Communication skillshttps://peerj.com/preprints/30232017-06-142017-06-14Nabin Paudel
Measurement of visual functions is critical to the detection and diagnosis of eye disease, particularly in children where eliciting symptomology can be challenging. An effective practitioner-patient relationship is crucial in optometric practice and has numerous benefits such as increased satisfaction, good compliance to assessment and treatment. The aim of this work is to share my experience of assessing visual functions (visual acuity, stereopsis, and computer-based visual psychophysical testing) in infants and children. I will discuss some unique strategies in order gain attention of children ranging from infants to preschoolers. The importance of the waiting area, use of colorful toys, appropriate use of tests and language are a few among many strategies for getting through a pediatric vision assessment. Based on my 9 years experience as a pediatric optometrist and a child vision researcher, these approaches has been quite successful in conducting hundreds of pediatric vision assessments. A friendly clinician equipped with interesting age appropriate tests and colorful toys along with some essential communication skills can easily conduct a thorough and efficient pediatric vision assessment.
Measurement of visual functions is critical to the detection and diagnosis of eye disease, particularly in children where eliciting symptomology can be challenging. An effective practitioner-patient relationship is crucial in optometric practice and has numerous benefits such as increased satisfaction, good compliance to assessment and treatment. The aim of this work is to share my experience of assessing visual functions (visual acuity, stereopsis, and computer-based visual psychophysical testing) in infants and children. I will discuss some unique strategies in order gain attention of children ranging from infants to preschoolers. The importance of the waiting area, use of colorful toys, appropriate use of tests and language are a few among many strategies for getting through a pediatric vision assessment. Based on my 9 years experience as a pediatric optometrist and a child vision researcher, these approaches has been quite successful in conducting hundreds of pediatric vision assessments. A friendly clinician equipped with interesting age appropriate tests and colorful toys along with some essential communication skills can easily conduct a thorough and efficient pediatric vision assessment.The zebrafish as a model system for analyzing mammalian and native α-crystallin promoter functionhttps://peerj.com/preprints/28892017-03-242017-03-24Mason PosnerKelly MurrayHayden EighingerAmy DrossmanZachary HaleyJustin NussbaumLarry L DavidKirsten J Lampi
Previous studies have used the zebrafish to investigate the biology of lens crystallin proteins and their roles in development and disease. However, little is known about zebrafish α-crystallin promoter function, how it compares to that of mammals, or whether mammalian α-crystallin promoter activity can be assessed using zebrafish embryos. We injected a variety of α-crystallin promoter fragments from each species combined with the coding sequence for green fluorescent protein (GFP) into zebrafish zygotes to determine the resulting spatiotemporal expression patterns in the developing embryo. We also measured mRNA levels and protein abundance for all three zebrafish α-crystallins. Our data showed that mouse and zebrafish αA-crystallin promoters generated similar GFP expression in the lens, but with earlier onset when using mouse promoters. Expression was also found in notochord and skeletal muscle in a small percentage of embryos. Mouse αB-crystallin promoter fragments drove GFP expression primarily in zebrafish skeletal muscle, with less common expression in notochord, lens, heart and in extraocular regions of the eye. A short fragment containing only a lens-specific enhancer region produced no GFP expression, suggesting that these lens responsive elements in the mouse are not used in the zebrafish. The two paralogous zebrafish αB-crystallin promoters produced subtly different expression profiles, with the αBa promoter driving expression equally in notochord and skeletal muscle while the αBb promoter resulted primarily in skeletal muscle expression. Messenger RNA for zebrafish αa, aBa and αBb were all detected by 1 day post fertilization (dpf). Parallel reaction monitoring (PRM) mass spectrometry was used to detect αA, αBa, and αBb peptides in digests of zebrafish embryos. In whole embryos, αA-crystallin was first detected by 2 dpf, peaked in abundance by 4-5 dpf, and was localized to the eye. αBa was also detected in whole embryo at nearly constant levels from 1-6 dpf, was also localized primarily to the eye, and its abundance in extraocular tissues decreased from 4-7 dpf. In contrast, due to its low abundance, no αBb protein could be detected in whole embryo, or dissected eye and extraocular tissues. Our results show that mammalian α-crystallin promoters can be efficiently screened in zebrafish embryos and that their controlling regions are well conserved, although their use in each species may reflect evolutionary changes in developmental roles for α-crystallins. An ontogenetic shift in zebrafish αBa-crystallin promoter activity provides an interesting system for examining the evolution and control of tissue specificity. Future studies that combine these promoter based approaches with the expanding ability to engineer the zebrafish genome via techniques such as CRISPR/Cas9 will allow the manipulation of protein expression to test hypotheses about lens crystallin function and its relation to lens biology and disease.
Previous studies have used the zebrafish to investigate the biology of lens crystallin proteins and their roles in development and disease. However, little is known about zebrafish α-crystallin promoter function, how it compares to that of mammals, or whether mammalian α-crystallin promoter activity can be assessed using zebrafish embryos. We injected a variety of α-crystallin promoter fragments from each species combined with the coding sequence for green fluorescent protein (GFP) into zebrafish zygotes to determine the resulting spatiotemporal expression patterns in the developing embryo. We also measured mRNA levels and protein abundance for all three zebrafish α-crystallins. Our data showed that mouse and zebrafish αA-crystallin promoters generated similar GFP expression in the lens, but with earlier onset when using mouse promoters. Expression was also found in notochord and skeletal muscle in a small percentage of embryos. Mouse αB-crystallin promoter fragments drove GFP expression primarily in zebrafish skeletal muscle, with less common expression in notochord, lens, heart and in extraocular regions of the eye. A short fragment containing only a lens-specific enhancer region produced no GFP expression, suggesting that these lens responsive elements in the mouse are not used in the zebrafish. The two paralogous zebrafish αB-crystallin promoters produced subtly different expression profiles, with the αBa promoter driving expression equally in notochord and skeletal muscle while the αBb promoter resulted primarily in skeletal muscle expression. Messenger RNA for zebrafish αa, aBa and αBb were all detected by 1 day post fertilization (dpf). Parallel reaction monitoring (PRM) mass spectrometry was used to detect αA, αBa, and αBb peptides in digests of zebrafish embryos. In whole embryos, αA-crystallin was first detected by 2 dpf, peaked in abundance by 4-5 dpf, and was localized to the eye. αBa was also detected in whole embryo at nearly constant levels from 1-6 dpf, was also localized primarily to the eye, and its abundance in extraocular tissues decreased from 4-7 dpf. In contrast, due to its low abundance, no αBb protein could be detected in whole embryo, or dissected eye and extraocular tissues. Our results show that mammalian α-crystallin promoters can be efficiently screened in zebrafish embryos and that their controlling regions are well conserved, although their use in each species may reflect evolutionary changes in developmental roles for α-crystallins. An ontogenetic shift in zebrafish αBa-crystallin promoter activity provides an interesting system for examining the evolution and control of tissue specificity. Future studies that combine these promoter based approaches with the expanding ability to engineer the zebrafish genome via techniques such as CRISPR/Cas9 will allow the manipulation of protein expression to test hypotheses about lens crystallin function and its relation to lens biology and disease.