Delayed differentiation of epidermal cells walls can underlie pedomorphosis in plants: the case of pedomorphic petals in the hummingbird-pollinated Caiophora hibiscifolia (Loasaceae, subfam. Loasoideae) species

Background Understanding the relationship between macroevolutionary diversity and variation in organism development is an important goal of evolutionary biology. Variation in the morphology of several plant and animal lineages is attributed to pedomorphosis, a case of heterochrony, where an ancestral juvenile shape is retained in an adult descendant. Pedomorphosis facilitated morphological adaptation in different plant lineages, but its cellular and molecular basis needs further exploration. Plant development differs from animal development in that cells are enclosed by cell walls and do not migrate. Moreover, in many plant lineages, the differentiated epidermis of leaves, and leaf-derived structures, such as petals, limits organ growth. We, therefore, proposed that pedomorphosis in leaves, and in leaf-derived structures, results from delayed differentiation of epidermal cells with respect to reproductive maturity. This idea was explored for petal evolution, given the importance of corolla morphology for angiosperm reproductive success. Results By comparing cell morphology and transcriptional profiles between 5 mm flower buds and mature flowers of an entomophile and an ornitophile Loasoideae species (a lineage that experienced transitions from bee- to hummingbird-pollination), we show that evolution of pedomorphic petals of the ornithophile species likely involved delayed differentiation of epidermal cells with respect to flower maturity. We also found that developmental mechanisms other than pedomorphosis might have contributed to evolution of corolla morphology. Conclusions Our results highlight a need for considering alternatives to the flower-centric perspective when studying the origin of variation in flower morphology, as this can be generated by developmental processes that are also shared with leaves. Graphical Abstract

Multiproduct manufacturer-retailer coordinated supply chain with adjustable rate for common parts, delayed differentiation, and multi-shipment

Operating in today’s turbulent and competitive world marketplaces, manufacturers must find the best production scheme and delivery policy to meet timely client’s multiproduct requirements and minimize the total manufacturing-shipment expenses. This study proposes a two-stage delayed differentiation model for a multiproduct manufacturer-retailer coordinated supply chain featuring the adjustable-rate for making common parts and a multi-shipment policy for transporting finished goods. The aim is to help present-day manufacturers achieve their operational goals mentioned above. The mathematical techniques help us build a specific model to explicitly represent the problem and derive its overall operating expense. Then, the convexity of the total expense is verified by Hessian matrix equations. The differential calculus helps derive the cost-minimized fabrication-shipment decision. This study offers an example to demonstrate the applicability and capabilities of our proposed model numerically. The following crucial information has been made available to the managers to facilitate their operating decision makings: (1) the problem’s best fabrication-shipment policy; (2) the collective influence of various common part’s completion rates and values on the problem’s total expenses and optimal fabrication-shipment policy; (3) the impact of various adjustable-rates in stage one on utilization and stage one’s uptime; (4) the details of cost contributors to the problem; and (5) the collective impacts of critical features on the problem’s performance.

EMX2 transcriptionally regulates Nfib expression in neural progenitor cells during early cortical development.

The nuclear factor one (NFI) transcription factors play key roles in regulating the onset of both neuronal and glial differentiation during cortical development. Reduced NFI expression results in delayed differentiation, which is associated with neurodevelopmental disorders in humans that include intellectual disability, agenesis of the corpus callosum and macrocephaly. Despite their importance, our understanding of how individual NFI family members are regulated during cortical development remains limited. Here, we demonstrate that in mice, the homeobox transcription factor EMX2 regulates Nfib expression in radial glial cells during cortical development. Using a combination of bioinformatics, molecular and histological approaches, we demonstrate that EMX2 is able to bind to the Nfib promoter to up-regulate Nfib expression. Unexpectedly, in vivo over-expression of EMX2 in wildtype animals does not further up-regulate NFIB but instead leads to its down-regulation. Therefore, our findings suggest that EMX2 is capable of both activating and repressing Nfib, in a context-dependent manner. This bi-directional control over Nfib expression enables fine-tuning of the total level of NFI proteins expressed and could be important for cell-type specific NFI functions.

Defect of LSS Disrupts Lens Development in Cataractogenesis

Congenital cataract is one of the leading causes of blindness in children worldwide. About one-third of congenital cataracts are caused by genetic defects. LSS, which encodes lanosterol synthase, is a causal gene for congenital cataracts. LSS is critical in preventing abnormal protein aggregation of various cataract-causing mutant crystallins; however, its roles in lens development remain largely unknown. In our study, we generated a mouse model harboring Lss G589S mutation, which is homologous to cataract-causing G588S mutation in human LSS. LssG589S/G589S mice exhibited neonatal lethality at postal day 0 (P0), whereas these mice showed severe opacity in eye lens. Also, we found that cataract was formed at E17.5 after we examined the opacity of embryonic lens from E13.5 to E18.5. Moreover, disrupted lens differentiation occurred at E14.5 prior to formation of the opacity of eye lens, shown as delayed differentiation of lens secondary fiber and disordered lens fiber organization. In addition, RNA-seq analysis indicated that cholesterol synthesis signaling pathways were significantly downregulated. Overall, our findings provide clear evidence that a mouse model harboring a homozygous Lss G589S mutation can recapitulate human congenital cataract. Our study points out that LSS functions as a critical determinant of lens development, which will contribute to better understanding LSS defects in cataractogenesis and developing therapies for cataracts.

Skeletal Ryanodine Receptors Are Involved in Impaired Myogenic Differentiation in Duchenne Muscular Dystrophy Patients

Duchenne muscular dystrophy (DMD) is characterized by progressive muscle wasting following repeated muscle damage and inadequate regeneration. Impaired myogenesis and differentiation play a major role in DMD as well as intracellular calcium (Ca2+) mishandling. Ca2+ release from the sarcoplasmic reticulum is mostly mediated by the type 1 ryanodine receptor (RYR1) that is required for skeletal muscle differentiation in animals. The study objective was to determine whether altered RYR1-mediated Ca2+ release contributes to myogenic differentiation impairment in DMD patients. The comparison of primary cultured myoblasts from six boys with DMD and five healthy controls highlighted delayed myoblast differentiation in DMD. Silencing RYR1 expression using specific si-RNA in a healthy control induced a similar delayed differentiation. In DMD myotubes, resting intracellular Ca2+ concentration was increased, but RYR1-mediated Ca2+ release was not changed compared with control myotubes. Incubation with the RYR-calstabin interaction stabilizer S107 decreased resting Ca2+ concentration in DMD myotubes to control values and improved calstabin1 binding to the RYR1 complex. S107 also improved myogenic differentiation in DMD. Furthermore, intracellular Ca2+ concentration was correlated with endomysial fibrosis, which is the only myopathologic parameter associated with poor motor outcome in patients with DMD. This suggested a potential relationship between RYR1 dysfunction and motor impairment. Our study highlights RYR1-mediated Ca2+ leakage in human DMD myotubes and its key role in myogenic differentiation impairment. RYR1 stabilization may be an interesting adjunctive therapeutic strategy in DMD.

Maize Male Reproductive Organs Affected by Different Timings of Water Deficit

Compared with female reproductive organs, the development of male reproductive organs was got less attention in maize because of its oversupply in amount even under water deficit. Thus, a rainout shelter experiment was designed to explore the effect of different timings of water deficit on pollen vitality and exterior and interior ultra-structure of pollen grains, starch particles in pollen grains, anther fresh weight, and vascular bundle number and its organizational structure in tassel pedicel. There were five water treatments included in this study, viz. well water treatment (CK), water deficit during 6- to 8- leaf stage (V6 − 8), 9- to 12- leaf stage (V9 − 12), 13-leaf stage to tasseling (V13 − T), and silking to blister (R1 − 2), respectively. Results showed that the percentage of pollen grains with strong vitality decreased remarkably by 27.3–45.9% under water deficits, while that of pollen grains with weak vitality increased by 27.2–34.7%. The percentage of pollen grains with no vitality was significantly increased only when water deficit occurred around silking, which was up to 8.6% for V13 − T and 19.7% for R1 − 2 compared with 1.0% for that of CK. Both shrunken pollen apertures (including annulus and operculum) and less starch particles might partially explain the weakened pollen vitality for water deficits before tasseling. Furthermore, the assimilation flux to male reproductive organs might be restricted by the influenced vascular bundle system under water deficits before tasseling, with manifestation showing in anther fresh weight and starch particle status in pollen grains. Specifically, V9 − 12 and V13 − T water deficits delayed differentiation of vascular bundle but had no influence on vascular bundle number, which might be one reason for their decreased anther fresh weight and less starch particles in pollen grains. Conversely, V6 − 8 water deficit significantly decreased vascular bundle number but had no significant influence on anther fresh weight and starch particles in pollen grains. R1 − 2 water deficit almost had no influences on above indicators except for pollen vitality. Overall, this research highlight that male reproductive organs could be influenced by water deficits in maize, which deserves more attention in further breeding especially under the background of high-quality requirement for pollen vitality of the maize hybrids that have a small tassel size.

MULTIPRODUCT MANUFACTURING WITH DELAYED DIFFERENTIATION, OUTSOURCING, EXPEDITED RATE, AND REWORK STRATEGIES

This study examines the effect of delayed differentiation, outsourcing, expedited fabrication rate, and rework strategies on optimal cycle-time decisions for a multi-item manufacturing system. Today’s manufacturing firms must simultaneously deal with externally increasing client multi-item requirements with rapid lead-time and high-quality products and internally on a limited capacity. This study is aimed at assisting manufacturers in meeting client needs in conditions of restricted-capacity and minimum total operating expenses, and adopts a delayed differentiation two-stage multiproduct manufacturing scheme to manage the end products’ commonality. The first stage produces all required common components, and the second stage fabricates individual finished goods. In both stages, we adopt the reworking of the inevitable nonconforming items produced to assure product quality. Furthermore, we implemented partial outsourcing of common parts’ batch and expedited the manufacturing rate of finished products to effectively reduce the uptimes in both stages. We explicitly developed a model to describe the characteristics of the problem. Mathematical analyses with optimization proved the cost function’s convexity and determined the cost-minimization rotation cycle policy. Finally, we numerically validated our model’s and results’ applicability and capability with a simulated example. Apart from creating a useful decision model, this study makes another important contribution to the existing literature in that its revelation of collective/individual effect of the manufacturing-relevant methods on the problem’s best-operating cycle policy and crucial performance indices helps manufacturers have better control over their operations and make effective and efficient managerial decisions.

Prioritization of the Best Sustainable Supply Chain Risk Management Practices Using a Structural Analysis Based-Approach

Companies attempt to improve the performance of their supply chain (SC) by distinguishing and presenting feasible sustainable development practices (SDP). Considering SDP without focusing on sustainability risks may disturb the company’s future. Very few studies in the extant literature have dealt with the impact of (SDP) on the supply chain risk management (SCRM). In fact, the aim of this paper is to classify and prioritize SDPs according to their priority for better risk management and effective SC performance. The proposed approach comprises two phases. First, 14 SDPs are identified and selected from the literature. Second, MICMAC (Matrice d’impacts croisés multiplication appliquée à un classement) method as a structural analysis method applies to identify and assess sustainable supply chain risk management (SSCRM) practices which reduce risk in the SC. The input data for each phase are based on Delphi technique, which is a process group used to collect the opinions of experts in the field. The aim of the proposed approach is to prioritize SSCRM practices and classify them into influential, non-influential, independent and dependent practices and their mutual relationships. The six key findings SSCRM practices from direct and indirect classification include the following elements: (1) Delayed differentiation, (2) Information sharing with upstream and/or downstream partners, (3) Simplification of product dismantling/anticipation of product end of life, (4) Supplier/subcontractor’s performance assessment, (5) establishing shared supply management and (6) establishment of contracts with transporters.