Developmental Genetic and Molecular Analysis of Drosophila Central Complex Lineages.

Complex behaviors are mediated by a diverse class of neurons and glia produced during development. Both neural stem cell-intrinsic and -extrinsic temporal cues regulate the appropriate number, molecular identity, and circuit assembly of neurons. The Drosophila central complex (CX) is a higher-order brain structure regulating various behaviors, including sensory-motor integration, celestial navigation, and sleep. Most neurons and glia in the adult CX are formed during larval development by 16 Type II neural stem cells (NSCs). Unlike Type I NSCs, which directly give rise to the ganglion mother cells (GMCs), Type II NSCs give rise to multiple intermediate neural progenitors (INPs), and each INP in turn generates multiple GMCs, hence fostering the generation of longer and more diverse lineages. This makes Type II NSCs a suitable model to unravel the molecular mechanisms regulating neural diversity in more complex lineages. In this review, we elaborate on the classification and identification of NSCs based on the types of division adopted and the molecular markers expressed in each type. In the end, we discuss genetic methods for lineage analysis and birthdating. We also explain the temporal expression of stem cell factors and genetic techniques to study how stem cell factors may regulate neural fate specification.

Lineage Analysis and Birthdating of Drosophila Central Complex Lineages.

From insects to humans, the nervous system generates complex behaviors mediated by distinct neural circuits that are composed of diverse cell types. During development, the spatiotemporal gene expression of the neural progenitors expands the diversity of neuronal and glial subtypes. Various neural stem cell-intrinsic and -extrinsic gene programs have been identified that are thought to play a major role in generating diverse neuronal and glial cell types. Drosophila has served as an excellent model system for discovering the fundamental principles of nervous system development and function. The sophisticated genetic tools allow us to link the origin and birth timing (the time when a particular neuron is born during development) of neuron types to unique neural stem cells (NSCs) and to a developmental time. In Drosophila, a special class of NSCs called Type II NSCs has adopted a more advanced division mode to generate lineages for the higher-order brain center, the central complex, which is an evolutionarily conserved brain region found in all insects. Type II NSCs, similar to the human outer radial glia, generate intermediate neural progenitors (INPs), which divide many times to produce about eight to 10 progeny. Both Type II NSCs and INPs express distinct transcription factors and RNA-binding proteins that have been proposed to regulate the specification of cell types populating the adult central complex. Here, we describe the recently invented lineage filtering system, called cell class-lineage intersection (CLIn), which enables the tracking and birthdating of the Type II NSC lineages. Using CLIn, one can easily generate clones of different Type II NSCs and identify not only the origins of neurons of interest but also their birth time.

The conserved RNA-binding protein Imp is required for the specification and function of olfactory navigation circuitry in Drosophila.

Complex behaviors depend on the precise developmental specification of neuronal circuits, but the relationship between genetic programs for neural development, circuit structure, and behavioral output is often unclear. The central complex (CX) is a conserved sensory-motor integration center in insects, which governs many higher-order behaviors and largely derives from a small number of type II neural stem cells (NSCs). Here, we show that Imp, a conserved IGF-II mRNA-binding protein expressed in type II NSCs, plays a role in specifying essential components of CX olfactory navigation circuitry. We show the following: (1) that multiple components of olfactory navigation circuitry arise from type II NSCs. (2) Manipulating Imp expression in type II NSCs alters the number and morphology of many of these circuit elements, with the most potent effects on neurons targeting the ventral layers of the fan-shaped body (FB). (3) Imp regulates the specification of Tachykinin-expressing ventral FB input neurons. (4) Imp is required in type II NSCs for establishing proper morphology of the CX neuropil structures. (5) Loss of Imp in type II NSCs abolishes upwind orientation to attractive odor while leaving locomotion and odor-evoked regulation of movement intact. Taken together, our findings establish that a temporally expressed gene can regulate the expression of a complex behavior by developmentally regulating the specification of multiple circuit components and provides a first step toward a developmental dissection of the CX and its roles in behavior.

The RNA-binding protein, Imp specifies olfactory navigation circuitry and behavior in Drosophila.

Complex behaviors depend on the precise developmental specification of neuronal circuits, but the relationship between genetic prograssms for neural development, circuit structure, and behavioral output is often unclear. The central complex (CX) is a conserved sensory-motor integration center in insects that governs many higher order behaviors and largely derives from a small number of Type II neural stem cells. Here, we show that Imp, a conserved IGF-II mRNA-binding protein expressed in Type II neural stem cells, specifies components of CX olfactory navigation circuitry. We show: (1) that multiple components of olfactory navigation circuitry arise from Type II neural stem cells and manipulating Imp expression in Type II neural stem cells alters the number and morphology of many of these circuit elements, with the most potent effects on neurons targeting the ventral layers of the fan-shaped body. (2) Imp regulates the specification of Tachykinin expressing ventral fan-shaped body input neurons. (3) Imp in Type II neural stem cells alters the morphology of the CX neuropil structures. (4) Loss of Imp in Type II neural stem cells abolishes upwind orientation to attractive odor while leaving locomotion and odor-evoked regulation of movement intact. Taken together, our work establishes that a single temporally expressed gene can regulate the expression of a complex behavior through the developmental specification of multiple circuit components and provides a first step towards a developmental dissection of the CX and its roles in behavior.

Five-year outcomes of digital diabetic eye screening in individuals aged 80 and 85 years.

OBJECTIVE: To assess the incidence of referable diabetic retinopathy (DR) in patients aged 80 and 85 years to determine whether screening interval can be extended safely in this age group. METHODS: Patients who were aged 80 and 85 years when they attended digital screening during April 2014-March 2015 were included. Screening results at baseline and over the next four years were analysed. RESULTS: 1880 patients aged 80 and 1105 patients aged 85 were included. Patients referred to hospital eye service (HES) for DR ranged from 0.7% to 1.4% in the 80-year-old cohort over 5 years. In this cohort a total of 76 (4%) were referred to HES for DR, of which 11 (0.6%) received treatment. Over the course of the follow up (FU), 403 (21%) died. In the 85-year-old cohort, referral to HES for DR each year ranged from 0.1% to 1.3%. In this cohort a total of 27 (2.4%) were referred to HES for DR, of which 4 (0.4%) received treatment. Over the course of follow-up 541(49%) died. All treated cases were for maculopathy in both cohorts and there were no cases of proliferative diabetic retinopathy requiring treatment. CONCLUSION: This study showed that the risk of progression of retinopathy is quite low in this age group and only a small proportion of patients developed referable retinopathy requiring treatment. This suggests relooking at the need for screening and ideal screening intervals in patients aged 80 years and over with no referable DR as they can be potentially classed as a group with low risk of sight loss.

The Drivers of Diversity: Integrated genetic and hormonal cues regulate neural diversity.

Proper functioning of the nervous system relies not only on the generation of a vast repertoire of distinct neural cell types but also on the precise neural circuitry within them. How the generation of highly diverse neural populations is regulated during development remains a topic of interest. Landmark studies in Drosophila have identified the genetic and temporal cues regulating neural diversity and thus have provided valuable insights into our understanding of temporal patterning of the central nervous system. The development of the Drosophila central complex, which is mostly derived from type II neural stem cell (NSC) lineages, showcases how a small pool of NSCs can give rise to vast and distinct progeny. Similar to the human outer subventricular zone (OSVZ) neural progenitors, type II NSCs generate intermediate neural progenitors (INPs) to expand and diversify lineages that populate higher brain centers. Each type II NSC has a distinct spatial identity and timely regulated expression of many transcription factors and mRNA binding proteins. Additionally, INPs derived from them show differential expression of genes depending on their birth order. Together type II NSCs and INPs display a combinatorial temporal patterning that expands neural diversity of the central brain lineages. We cover advances in current understanding of type II NSC temporal patterning and discuss similarities and differences in temporal patterning mechanisms of various NSCs with a focus on how cell-intrinsic and extrinsic hormonal cues regulate temporal transitions in NSCs during larval development. Cell extrinsic ligands activate conserved signaling pathways and extrinsic hormonal cues act as a temporal switch that regulate temporal progression of the NSCs. We conclude by elaborating on how a progenitor's temporal code regulates the fate specification and identity of distinct neural types. At the end, we also discuss open questions in linking developmental cues to neural identity, circuits, and underlying behaviors in the adult fly.

Knowledge, Attitude, and Perceptions about In Vitro Fertilization (IVF) among Women of Childbearing Age in Cape Coast, Ghana.

Background: Infertility impacts a lot of considerable negative social effects on the lives of infertile partners, especially females, who repeatedly experience the emotional sequelae of childlessness. The study's goal was to assess women of reproductive ages' awareness of IVF treatments, as well as their attitudes and misunderstandings about them in Cape Coast, Ghana. Methods: A total of 437 reproductive-age women in Cape Coast Metropolis were recruited using a simple random sampling approach for this Cross-Sectional Descriptive study. Data were collected with a semistructured interviewer-administered questionnaire and were analyzed using IBM SPSS version 26.0, and p ≤ 0.05 was considered significant. Results: The mean age was calculated to be 25.33 ± 0.066 years with a greater proportion, 65.7% within 15-24 years, 76.5% had no or had never had a child before. 93.4% were of the Christian faith, 66.8% were aware of IVF, and 74.8% think IVF offers hope. Although 41.4% believe it is not a natural procedure and 44.6% believe IVF children are normal but not natural. While 72.1% believe the treatment is very costly, and 40.7% believe it is not affordable or accessible. The majority believe IVF kids are legitimate (76.9%), and so should be welcomed by society (86.5%). The overall opinion of IVF service acceptability was 81.7% good. Seventy-two and three percent did not know whether IVF services are available in Cape Coast. Also, 48.1% were aware that IVF may result in pregnancy failure, with fewer than half (43.5%) believing it could be linked to genetic problems in the baby. The majority (60.4%) were willing to use IVF services, and 82.8% will utilize just their husband's sperm technique. While others may not want to undergo any form of IVF technique because they desire to conceive naturally (51.0%) and 22.4% may be unable to pay for it. Educational status and awareness of the availability of IVF services were factors that were significantly associated with their overall good perception of IVF services. Also, age, marital status, number of live children, occupation, educational status, awareness, and their overall perception were factors that are significantly associated with their preparedness to utilize IVF services. Conclusion: Overall, women's opinions of IVF and their readiness to use them were favorable, and they think it offers hope for their condition since they were well-informed about its forms and that infertility may be a result of several factors, all of which may need IVF services. It does not matter if it is difficult to obtain, expensive, or unavailable. It is recommended that the government collaborates with healthcare providers to investigate ways through the mass media in the drive to clear the misconceptions and improve the public understanding of the IVF procedure towards its utilization, thereby reducing the burden of childlessness and the resulting psychological disorders among couples, this has implications for joyful homes and societal growth.

A high energy phosphate jump - From pyrophospho-inositol to pyrophospho-serine.

Inositol pyrophosphates (PP-IPs) are a class of energy rich metabolites present in all eukaryotic cells. The hydroxyl groups on these water soluble derivatives of inositol are substituted with diphosphate and monophosphate moieties. Since the discovery of PP-IPs in the early 1990s, enormous progress has been made in uncovering pleiotropic roles for these small molecules in cellular physiology. PP-IPs exert their effect on proteins in two ways - allosteric regulation by direct binding, or post-translational regulation by serine pyrophosphorylation, a modification unique to PP-IPs. Serine pyrophosphorylation is achieved by Mg2+-dependent, but enzyme independent transfer of a ß-phosphate from a PP-IP to a pre-phosphorylated serine residue located in an acidic motif, within an intrinsically disordered protein sequence. This distinctive post-translational modification has been shown to regulate diverse cellular processes, including rRNA synthesis, glycolysis, and vesicle transport. However, our understanding of the molecular details of this phosphotransfer from pyrophospho-inositol to generate pyrophospho-serine, is still nascent. This review discusses our current knowledge of protein pyrophosphorylation, and recent advances in understanding the mechanism of this important yet overlooked post-translational modification.