-
Frontiers in Physiology 2022is widely appreciated by the surrounding population due to its culinary delicacy and rich nutrients. The breeding industry is very prosperous and molting is one of the...
is widely appreciated by the surrounding population due to its culinary delicacy and rich nutrients. The breeding industry is very prosperous and molting is one of the important growth characteristics. Research on the regulation of molting in is still in the initial stages. There is currently no relevant information on the regulatory mechanisms of heart development following molting. Comparative transcriptome analysis was used to study developmental regulation mechanisms in the heart of at the post-molt and inter-molt stages. The results indicated that many regulatory pathways and genes involved in regeneration, anti-oxidation, anti-aging and the immune response were significantly upregulated after molting in . Aside from cardiac development, the differentially expressed genes (DEGs) were relevant to myocardial movement and neuronal signal transduction. DEGs were also related to the regulation of glutathione homeostasis and biological rhythms in regard to anti-oxidation and anti-aging, and to the regulation of immune cell development and the immune response. This study provides a theoretical framework for understanding the regulation of molting in and in other economically important crustaceans.
PubMed: 36237529
DOI: 10.3389/fphys.2022.948511 -
Genes Dec 2021Molting is natural adaptation to climate change in all birds, including chickens. Forced molting (FM) can rejuvenate and reactivate the reproductive potential of aged...
Molting is natural adaptation to climate change in all birds, including chickens. Forced molting (FM) can rejuvenate and reactivate the reproductive potential of aged hens, but the effect of natural molting (NM) on older chickens is not clear. To explore why FM has a dramatically different effect on chickens compared with NM, the transcriptome analyses of the hypothalamus and ovary in forced molted and natural molted hens at two periods with feathers fallen and regrown were performed. Additionally, each experimental chicken was tested for serological indices. The results of serological indices showed that growth hormone, thyroid stimulating hormone, and thyroxine levels were significantly higher ( < 0.05) in forced molted hens than in natural molted hens, and calcitonin concentrations were lower in the forced molted than in the natural molted hens. Furthermore, the transcriptomic analysis revealed a large number of genes related to disease resistance and anti-aging in the two different FM and NM periods. These regulatory genes and serological indices promote reproductive function during FM. This study systematically revealed the transcriptomic and serological differences between FM and NM, which could broaden our understanding of aging, rejuvenation, egg production, and welfare issues related to FM in chickens.
Topics: Aging; Animals; Avian Proteins; Chickens; Feathers; Female; Gene Expression Profiling; Gene Expression Regulation, Developmental; Hormones; Hypothalamus; Molting; Ovary; Transcriptome
PubMed: 35052428
DOI: 10.3390/genes13010089 -
PLoS Neglected Tropical Diseases Jan 2017Mosquitoes host communities of microbes in their digestive tract that consist primarily of bacteria. We previously reported that Aedes aegypti larvae colonized by a...
Mosquitoes host communities of microbes in their digestive tract that consist primarily of bacteria. We previously reported that Aedes aegypti larvae colonized by a native community of bacteria and gnotobiotic larvae colonized by only Escherichia coli develop very similarly into adults, whereas axenic larvae never molt and die as first instars. In this study, we extended these findings by first comparing the growth and abundance of bacteria in conventional, gnotobiotic, and axenic larvae during the first instar. Results showed that conventional and gnotobiotic larvae exhibited no differences in growth, timing of molting, or number of bacteria in their digestive tract. Axenic larvae in contrast grew minimally and never achieved the critical size associated with molting by conventional and gnotobiotic larvae. In the second part of the study we compared patterns of gene expression in conventional, gnotobiotic and axenic larvae by conducting an RNAseq analysis of gut and nongut tissues (carcass) at 22 h post-hatching. Approximately 12% of Ae. aegypti transcripts were differentially expressed in axenic versus conventional or gnotobiotic larvae. However, this profile consisted primarily of transcripts in seven categories that included the down-regulation of select peptidases in the gut and up-regulation of several genes in the gut and carcass with roles in amino acid transport, hormonal signaling, and metabolism. Overall, our results indicate that axenic larvae exhibit alterations in gene expression consistent with defects in acquisition and assimilation of nutrients required for growth.
Topics: Aedes; Animals; Bacteria; Gastrointestinal Microbiome; Gastrointestinal Tract; Insect Proteins; Larva; Transcriptome
PubMed: 28060822
DOI: 10.1371/journal.pntd.0005273 -
Insect Biochemistry and Molecular... Oct 2022The insect cuticle is a key component of their success, being important for protection, communication, locomotion, and support. Conversely, as an exoskeleton, it also...
The insect cuticle is a key component of their success, being important for protection, communication, locomotion, and support. Conversely, as an exoskeleton, it also limits the size of the insect and must be periodically molted and a new one synthesized, to permit growth. To achieve this, the insect secretes a solution of chitinases, proteases and other proteins, known collectively as molting fluid, during each molting process to break down and recycle components of the old cuticle. Previous research has focused on the degradative enzymes in molting fluid and offered some characterization of their biochemical properties. However, identification of the specific proteins involved remained to be determined. We have used 2D SDS-PAGE and LC/MS-based proteomic analysis to identify proteins in the molting fluid of the tobacco hornworm, Manduca sexta, undergoing the larval to pupal molt. We categorized these proteins based on their proposed functions including chitin metabolism, proteases, peptidases, and immunity. This analysis complements previous reported work on M. sexta molting fluid and identifies candidate genes for enzymes involved in cuticle remodeling. Proteins classified as having an immune function highlight potential for molting fluid to act as an immune barrier to prevent infections during the cuticle degradation and ecdysis processes. Several proteins known to function in melanin synthesis as an immune response in hemolymph were present in molting fluid. We demonstrated that the bacterium Micrococcus luteus and the entomopathogenic fungus Beauveria bassiana can stimulate activation of phenoloxidase in molting fluid, indicating that the recognition proteins, protease cascade, and prophenoloxidase needed for melanin synthesis are present as a defense against infection during cuticle degradation. This analysis offers insights for proteins that may be important not only for molting in M. sexta but for insects in general.
Topics: Animals; Chitin; Chitinases; Endopeptidases; Insect Proteins; Larva; Manduca; Melanins; Molting; Monophenol Monooxygenase; Peptide Hydrolases; Proteomics; Pupa
PubMed: 36115517
DOI: 10.1016/j.ibmb.2022.103844 -
Developmental Biology Mar 2022Molting is a widespread feature in the development of many invertebrates, including nematodes and arthropods. In Caenorhabditis elegans, the highly conserved protein...
Molting is a widespread feature in the development of many invertebrates, including nematodes and arthropods. In Caenorhabditis elegans, the highly conserved protein kinases NEKL-2/NEK8/9 and NEKL-3/NEK6/7 (NEKLs) promote molting through their involvement in the uptake and intracellular trafficking of epidermal cargos. We found that the relative requirements for NEKL-2 and NEKL-3 differed at different life-cycle stages and under different environmental conditions. Most notably, the transition from the second to the third larval stage (L2→L3 molt) required a higher level of NEKL function than during several other life stages or when animals had experienced starvation at the L1 stage. Specifically, larvae that entered the pre-dauer L2d stage could escape molting defects when transiting to the (non-dauer) L3 stage. Consistent with this, mutations that promote entry into L2d suppressed nekl-associated molting defects, whereas mutations that inhibit L2d entry reduced starvation-mediated suppression. We further showed that loss or reduction of NEKL functions led to defects in the transcription of cyclically expressed molting genes, many of which are under the control of systemic steroid hormone regulation. Moreover, the timing and severity of these transcriptional defects correlated closely with the strength of nekl alleles and with their stage of arrest. Interestingly, transit through L2d rescued nekl-associated expression defects in suppressed worms, providing an example of how life-cycle decisions can impact subsequent developmental events. Given that NEKLs are implicated in the uptake of sterols by the epidermis, we propose that loss of NEKLs leads to a physiological reduction in steroid-hormone signaling and consequent defects in the transcription of genes required for molting.
Topics: Alleles; Animals; Animals, Genetically Modified; CRISPR-Cas Systems; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Endocytosis; Epidermis; Forkhead Transcription Factors; Gene Expression Regulation, Developmental; Larva; Life Cycle Stages; Loss of Function Mutation; Molting; NIMA-Related Kinases; Signal Transduction; Starvation; Sterols; Up-Regulation
PubMed: 35038442
DOI: 10.1016/j.ydbio.2022.01.001 -
Parasitology International Feb 2015The salmon louse (Lepeophtheirus salmonis) is an ectoparasitic copepod causing severe problems to the fish farming industry and to wild salmonids. Morphologically, all...
The salmon louse (Lepeophtheirus salmonis) is an ectoparasitic copepod causing severe problems to the fish farming industry and to wild salmonids. Morphologically, all stages in the life cycle of L. salmonis have been described in detail based on successive samples from host populations. However, the rate of development differs between males and females as well as between individuals. It has therefore been difficult to observe development within stages, and this has led to a longstanding misinterpretation of the number of chalimus stages. Here samples of chalimi obtained for 12 consecutive days were observed daily in incubators. Chalimus 1 was able to molt in incubators only when fully grown and close to molting, whereas chalimus 2 was able to molt at about 60% of total instar growth. Total length instar growth was about 35% in both chalimus 1 and chalimus 2 and about equal among males and females; the cephalothorax increased by about 12% and the posterior body by about 80%. Instar growth was probably the main factor that led to the former belief that L. salmonis had four chalimus stages. Relative total length increase at molting was at the same order of magnitude as instar growth, but total length of females increased significantly more than that of males at molting. Consequently, a sexual size dimorphism was established upon molting to chalimus 2 and males were about 10% smaller than females. While growth by molting was mainly caused by cephalothorax increase, instar growth was mainly due to increase of the posterior body. The cephalothorax/total length ratio decreased from beginning to end of the instar phase suggesting that it may be used as an instar age marker. Male and female chalimus 2 can almost uniquely be identified by cephalothorax length. Chalimus 1 lasted between 5 and 6 days for males and between 6 and 7 days for females at 10°C. Chalimus 2 males lasted between 6 and 7 days and females between 7 and 8 days.
Topics: Animals; Copepoda; Ectoparasitic Infestations; Female; Fish Diseases; Larva; Life Cycle Stages; Male; Molting; Salmo salar; Sex Characteristics
PubMed: 25451218
DOI: 10.1016/j.parint.2014.10.006 -
Physiological and Biochemical Zoology :... 2021AbstractHarbor seals () live in cold temperate or polar seas and molt annually, renewing their fur over a period of approximately 4 wk. Epidermal processes at this time...
AbstractHarbor seals () live in cold temperate or polar seas and molt annually, renewing their fur over a period of approximately 4 wk. Epidermal processes at this time require a warm skin; therefore, to avoid an excessive energy cost at sea during the molt, harbor seals and many other pinnipeds increase the proportion of time they are hauled out on land. We predicted that metabolic rate during haul-out would be greater during the molt to sustain an elevated skin temperature in order to optimize skin and hair growth. To examine this, we measured post-haul-out oxygen consumption () in captive harbor seals during molt and postmolt periods. We recorded greater of seals while they were molting than when the molt was complete. Post-haul-out increased faster and reached a greater maximum during the first 40 min. Thereafter, decreased but still remained greater, suggesting that while metabolic rate was relatively high throughout haul-outs, it was most pronounced in the first 40 min. Air temperature, estimated heat increment of feeding, and mass also explained 15.5% of variation over 180 min after haul-out, suggesting that the environment, feeding state, and body size influenced the metabolic rate of individual animals. These results show that molting seals have greater metabolic rates when hauled out, especially during the early stages of the haul-out period. As a consequence, human disturbance that changes the haul-out behavior of molting seals will increase their energy costs and potentially extend the duration of the molt.
Topics: Animals; Energy Metabolism; Feeding Behavior; Male; Molting; Oxygen Consumption; Phoca; Seasons
PubMed: 33710938
DOI: 10.1086/713958 -
BMC Developmental Biology Nov 2020Molting is an essential biological process occurring characteristic times throughout the life cycle of holometabolous insects. However, it is not clear how insects...
BACKGROUND
Molting is an essential biological process occurring characteristic times throughout the life cycle of holometabolous insects. However, it is not clear how insects determine the direction of molting to remain status quo or to initiate metamorphosis. To explore the functional factors that determine the direction of molts, liquid chromatography-mass spectrometry was used to identify the molecules involved in larval and metamorphic molting, and the differentially expressed proteins (DEPs) were compared in the two processes.
RESULTS
There were 321 and 1140 DEPs identified in larval and metamorphic molting process, respectively. Bioinformatics analyses show that the amino sugar pathway was up-regulated in both processes. The up-regulated protease contributed to the metamorphosis. In addition, several proteins with different expression patterns in larval-larval and larval-pupal transitions, including Endochitinase, GRIM-19 (Genes associated with retinoid-IFN-induced mortality-19), IDE (Insulin-degrading enzyme), Sorcin (Soluble resistance related calcium binding protein), OBP (Odorant-binding protein-2 precursor), TRAP1(Tumor necrosis factor receptor associated protein-1), etc., were further identified by parallel reaction monitoring, which may play diverse functions in larval-larval and larval-pupal transitions.
CONCLUSIONS
These results provide a proteomic insight into molecules involved in larval and metamorphic molts, and will likely improve the current understanding of determination of direction of molts.
Topics: Animals; Gene Expression Regulation, Developmental; Insect Proteins; Larva; Lepidoptera; Metamorphosis, Biological; Molting; Proteomics; Pupa; Reproducibility of Results
PubMed: 33234135
DOI: 10.1186/s12861-020-00227-z -
MSystems Oct 2021Molting is a crucial lifelong process in the growth, development, and reproduction of crustaceans. In mud crab (), new exoskeleton, gills, and appendages are formed...
Molting is a crucial lifelong process in the growth, development, and reproduction of crustaceans. In mud crab (), new exoskeleton, gills, and appendages are formed after a molting, which contributes to a 40 to 90% increase in body weight. However, little is currently known about the associations between molting and the dynamic changes of microbiota and physiological characteristics in mud crabs. In this study, the effects of molting on changes of the microbiome, immune response, and digestive enzyme activities in mud crabs were investigated. The results showed dynamic changes in the abundances and community compositions of crab-associated microbiota harboring the gills, subcuticular epidermis, hepatopancreas, midgut, and hemolymph during molting. Renewed microbiota was observed in the gills and midgut of crabs at the postmolt stages, which seems to be related to the formation of a new exoskeleton after the molting. A significant positive correlation between the expression of two antimicrobial peptide (AMP) genes (ALF5 and Crustin) and the relative abundance of two predominant microorganisms ( and ) in hemolymph was observed in the whole molt cycle, suggesting that AMPs play a role in modulating hemolymph microbiota. Furthermore, digestive enzymes might play a vital role in the changes of microbiota harboring the hepatopancreas and midgut, which provide suitable conditions for restoring and reconstructing host-microbiome homeostasis during molting. In conclusion, this study confirms that molting affects host-associated microbiota and further sheds light on the effects on the immune response and the digestive systems as well. Molting is crucial for crustaceans. In mud crab, its exoskeleton is renewed periodically during molting, and this process is an ideal model to study the effects of host development on its microbiota. Here, multiple approaches were used to investigate the changes in microbial taxa, immune response, and digestive enzyme activity with respect to molting in mud crab. The results found that a renewed microbiota was generated in the gills and midgut of crab after a molt. A significant positive correlation between changes in the relative abundances of microbes (such as and ) and the expression of AMP genes (ALF5 and Crustin) was observed in the hemolymph of crabs during the whole molt cycle, suggesting the modulation of hemolymph microbes by AMPs. Furthermore, the digestive enzymes were found to participate in the regulation of microbiota in hepatopancreas and midgut, consequently providing a suitable condition for the restoration and reconstruction of host-microbiome homeostasis during the molting. This study confirms that molting affects the microbial communities and concomitantly influences the immune and digestive systems in mud crabs. This is also the first time the homeostasis of the host and microbiome, and the associations between molting and physiological characteristics in crustaceans, have been revealed.
PubMed: 34636669
DOI: 10.1128/mSystems.00917-21 -
General and Comparative Endocrinology Jul 2021Adipose tissue is essential to endotherms for thermoregulation and energy storage as well as functioning as an endocrine organ. Adipose derived hormones, or adipokines,...
Adipose tissue is essential to endotherms for thermoregulation and energy storage as well as functioning as an endocrine organ. Adipose derived hormones, or adipokines, regulate metabolism, energy expenditure, reproduction, and immune function in model systems but are less well studied in wildlife. Female northern elephant seals (NES) achieve high adiposity during foraging and then undergo natural fasts up to five weeks long during haul-outs associated with reproduction and molting, resulting in large changes in adipose reserves. We measured circulating levels of four adipokines: leptin, resistin, adiponectin, and kisspeptin-54, in 196 serum samples from female NES at the beginning and end of their breeding and molting fasts. We examined the relationships between these adipokines and life-history stage, adiposity, mass, cortisol, and an immune cytokine involved in the innate immune response interleukin 6 (IL-6). All four adipokines varied with life-history stage. Leptin concentrations were highest at the beginning of the breeding haul-out. Resistin concentrations were higher throughout the breeding haul-out compared to the molt haul-out. Adiponectin concentrations were highest at the beginning of both haul-outs. Kisspeptin-54 concentrations were highest at the end of the breeding haul-out. Leptin, resistin, and adiponectin were associated with measures of body condition, either adiposity, mass, or both. Resistin, adiponectin, and kisspeptin-54 were associated with circulating cortisol concentrations. Resistin was strongly associated with circulating IL-6, a multifunctional cytokine. Adiponectin was associated with glucose concentrations, suggesting a potential role in tissue-specific insulin sensitivity during life-history stages categorized by high adiposity. Increased cortisol concentrations late in lactation were associated with increased kisspeptin-54, suggesting a link to ovulation initiation in NES. This study suggests dramatic changes in circulating adipokines with life-history and body condition that may exert important regulatory roles in NES. The positive relationship between adiponectin and adiposity as well as the lack of a relationship between leptin and kisspeptin-54 differed from model systems. These differences from biomedical model systems suggest the potential for modifications of expression and function of adipose-derived hormones in species that undergo natural changes in adiposity as part of their life-history.
Topics: Adipokines; Adiponectin; Adiposity; Animals; Fasting; Female; Kisspeptins; Leptin; Resistin; Seals, Earless
PubMed: 33781740
DOI: 10.1016/j.ygcen.2021.113760