Generalized modality responses in primary sensory neurons of awake mice during the development of neuropathic pain

IntroductionPeripheral sensory neurons serve as the initial responders to the external environment. How these neurons react to different sensory stimuli, such as mechanical or thermal forces applied to the skin, remains unclear.MethodsUsing in vivo two-photon Ca2+ imaging in the lumbar 4 dorsal root ganglion (DRG) of awake Thy1.2-GCaMP6s mice, we assessed neuronal responses to various mechanical (punctate or dynamic) and thermal forces (heat or cold) sequentially applied to the paw plantar surface.ResultsOur data indicate that in normal awake male mice, approximately 14 and 38% of DRG neurons respond to either single or multiple modalities of stimulation. Anesthesia substantially reduces the number of responsive neurons but does not alter the ratio of cells exhibiting single-modal responses versus multi-modal responses. Following peripheral nerve injury, DRG cells exhibit a more than 5.1-fold increase in spontaneous neuronal activity and a 1.5-fold increase in sensory stimulus-evoked activity. As neuropathic pain resulting from nerve injury progresses, the polymodal nature of sensory neurons intensifies. The polymodal population increases from 39.1 to 56.9%, while the modality-specific population decreases from 14.7 to 5.0% within a period of 5 days.DiscussionOur study underscores polymodality as a significant characteristic of primary sensory neurons, which becomes more pronounced during the development of neuropathic pain

Plastid-nucleus communication involves calcium-modulated MAPK signalling

Chloroplast retrograde signals play important roles in coordinating the plastid and nuclear gene expression and are critical for proper chloroplast biogenesis and for maintaining optimal chloroplast functions in response to environmental changes in plants. Until now, the signals and the mechanisms for retrograde signalling remain poorly understood. Here we identify factors that allow the nucleus to perceive stress conditions in the chloroplast and to respond accordingly by inducing or repressing specific nuclear genes encoding plastid proteins. We show that ABI4, which is known to repress the LHCB genes during retrograde signalling, is activated through phosphorylation by the MAP kinases MPK3/MPK6 and the activity of these kinases is regulated through 14-3-3 omega-mediated Ca2+-dependent scaffolding depending on the chloroplast calcium sensor protein CAS. These findings uncover an additional mechanism in which chloroplast-modulated Ca2+ signalling controls the MAPK pathway for the activation of critical components of the retrograde signalling chain

Plastid-nucleus communication involves calcium-modulated MAPK signalling

Chloroplast retrograde signals play important roles in coordinating the plastid and nuclear gene expression and are critical for proper chloroplast biogenesis and for maintaining optimal chloroplast functions in response to environmental changes in plants. Until now, the signals and the mechanisms for retrograde signalling remain poorly understood. Here we identify factors that allow the nucleus to perceive stress conditions in the chloroplast and to respond accordingly by inducing or repressing specific nuclear genes encoding plastid proteins. We show that ABI4, which is known to repress the LHCB genes during retrograde signalling, is activated through phosphorylation by the MAP kinases MPK3/MPK6 and the activity of these kinases is regulated through 14-3-3 omega-mediated Ca2+-dependent scaffolding depending on the chloroplast calcium sensor protein CAS. These findings uncover an additional mechanism in which chloroplast-modulated Ca2+ signalling controls the MAPK pathway for the activation of critical components of the retrograde signalling chain

The roles of chloroplast proteases in the biogenesis and maintenance of photosystem II

AbstractPhotosystem II (PSII) catalyzes one of the key reactions of photosynthesis, the light-driven conversion of water into oxygen. Although the structure and function of PSII have been well documented, our understanding of the biogenesis and maintenance of PSII protein complexes is still limited. A considerable number of auxiliary and regulatory proteins have been identified to be involved in the regulation of this process. The carboxy-terminal processing protease CtpA, the serine-type protease DegP and the ATP-dependent thylakoid-bound metalloprotease FtsH are critical for the biogenesis and maintenance of PSII. Here, we summarize and discuss the structural and functional aspects of these chloroplast proteases in these processes. This article is part of a Special Issue entitled: SI: Photosystem II

Intracellular Signaling from Plastid to Nucleus

Intracellular signaling from plastids to the nucleus, called retrograde signaling, coordinates the expression of nuclear and plastid genes and is essential for plastid biogenesis and for maintaining plastid function at optimal levels. Recent identification of several components involved in plastid retrograde generation, transmission, and control of nuclear gene expression has provided significant insight into the regulatory network of plastid retrograde signaling. Here, we review the current knowledge of multiple plastid retrograde signaling pathways, which are derived from distinct sources, and of possible plastid signaling molecules. We describe the retrograde signaling-dependent regulation of nuclear gene expression, which involves multilayered transcriptional control, as well as the transcription factors involved. We also summarize recent advances in the identification of key components mediating signal transduction from plastids to the nucleus

Molecular Regulation of Cotton Fiber Development: A Review

Cotton (Gossypium spp.) is an economically important natural fiber crop. The quality of cotton fiber has a substantial effect on the quality of cotton textiles. The identification of cotton fiber development-related genes and exploration of their biological functions will not only enhance our understanding of the elongation and developmental mechanisms of cotton fibers but also provide insights that could aid the cultivation of new cotton varieties with improved fiber quality. Cotton fibers are single cells that have been differentiated from the ovule epidermis and serve as a model system for research on single-cell differentiation, growth, and fiber production. Genes and fiber formation mechanisms are examined in this review to shed new light on how important phytohormones, transcription factors, proteins, and genes linked to fiber development work together. Plant hormones, which occur in low quantities, play a critically important role in regulating cotton fiber development. Here, we review recent research that has greatly contributed to our understanding of the roles of different phytohormones in fiber development and regulation. We discuss the mechanisms by which phytohormones regulate the initiation and elongation of fiber cells in cotton, as well as the identification of genes involved in hormone biosynthetic and signaling pathways that regulate the initiation, elongation, and development of cotton fibers

Regulation mechanism of sulfate uptake and metabolism in higher plants

Sulfate assimilation is a pathway used by prokaryotes,fungi and photosynthetic organisms to convert inorganic sulfate to sulfide,which is further incorporated into carbon skeletons of amino acids to form cysteine or homocysteine.Sulfate,the major form of inorganic sulfur utilized by plants,is absorbed and transported by specific sulfate transporters into plastids,especially chloroplasts,where it is reduced and assimilated into cysteine.The metabolic pathway is highly regulated in a demand-driven manner.However,this regulation is not necessarily identical in various biological groups.The molecular mechanisms of sulfate uptake and metabolism regulation in higher plants were reviewed here,the issues and potential research strategies on the molecular mechanisms of sulfate metabolism regulation were preliminarily discussed as well

H₂O₂-responsive proteomics in plant leaves

Plant leaves are important organ for sensing H2O2 signals. This paper analyzes the diverse prote in patterns in plants such as Oryza sativa,Triticum aestivum,Brachypodium distachyon and Citrus aurantium under various H2O2 stress conditions. The change of signaling and metabolic pathways (such as photosynthesis,carbohydrate and energy metabolism,transcriptional regulation,protein synthesis and fate,stress and defense,signal transduction,basal metabolism,etc.) when the leaves put in H2O2-responsive networks were clarified. And the molecular regulatory mechanism of response to H2O2 stress in plant leaves was expounded as well

The nutritional and industrial significance of cottonseeds and genetic techniques in gossypol detoxification

Societal Impact Statement Gossypol and its derivatives represent a class of toxic and immunosuppressive compounds that are naturally synthesized in cottonseed. These compounds pose several health hazards to humans and animals, such as heart and lung damage, breathing difficulties, and death in swine. In poultry, gossypol reduces egg production and slows growth. Studies have also shown that gossypol can indirectly harm humans and animals through the food chain. Although several physical and chemical approaches are adopted to reduce gossypol levels in cottonseed before food and feed processing, these techniques are expensive. Therefore, genetically regulating gossypol production in cotton could provide a cheaper alternative. Summary Cotton (Gossypium spp.), the most important fiber crop, is cultivated in over a hundred countries to provide raw materials for the growing textile industry. The seed obtained after delinting cotton is a rich source of protein with a vast potential for oil and feed production. Cottonseed oil production is estimated at 5.08 million metric tons and is expected to generate over 6.56 billion United States Dollars in revenue by 2029. The cake from defatted cottonseed is used as animal feed and food supplements. However, the contamination of gossypol in cottonseed limits its use. Gossypol ingestion impairs weight gain and causes anorexia, respiratory distress, and death under extreme exposure. This review highlights the significance of cottonseed oil and meal; the pharmacological uses and impact of gossypol; the chemistry, toxicity, and bioactivity of gossypol; and the physical and chemical methods used in gossypol removal during feed and food supplement processing. In addition, the biosynthetic pathway of gossypol and attempts to genetically transform some key regulators of this pathway to produce glandless cottonseed or reduce the gossypol levels in the seed are discussed