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Journal of Insect Science (Online) Jul 2021Chitin deacetylases (CDAs) are chitin-degrading enzymes that play a key role in insect molting. In this study, we identified and characterized four full-length cDNAs of...
Chitin deacetylases (CDAs) are chitin-degrading enzymes that play a key role in insect molting. In this study, we identified and characterized four full-length cDNAs of CDAs from Sogatella furcifera (Horváth). Developmental expression showed that SfCDA1 and SfCDA2 were expressed at all nymph developmental stages, SfCDA3 and SfCDA4 were mainly expressed in the third-instar to fifth-instar nymph stages, whereas tissue-specific analyses indicated that four CDA genes were mainly high expressed in the integument and head during the fifth-instar nymph. RNA interference (RNAi) results revealed that SfCDA1, SfCDA2, and SfCDA4 are associated with molting defect and high mortality with nymph-adult molting. Furthermore, transcripts of chitin synthase 1 variants (SfCHS1, SfCHS1a, and SfCHS1b) were significantly downregulated and causing significant changes in the expression levels of trehalases (TRE1 and TRE2) in the SfCDA1, SfCDA2, and SfCDA4 dsRNA treatment groups. By contrast, no significant phenotypic characteristics were observed after dsSfCDA3 injection. Taken together, our results suggest that SfCDA1, SfCDA2, and SfCDA4 play a vital role in nymph-adult transition, and these genes could regulate chitin biosynthesis expression levels.
Topics: Amidohydrolases; Animals; Chitin; DNA, Complementary; Genes, Insect; Hemiptera; Insect Proteins; Molting; Nymph; Phylogeny; RNA Interference; Wings, Animal
PubMed: 34333649
DOI: 10.1093/jisesa/ieab051 -
Poultry Science Nov 2016The aim of this study was to investigate the efficacy of feed-grade preparations of mannan oligosaccharides ( MOS: ) and oregano essential oil ( OEO: ) in forced molted... (Comparative Study)
Comparative Study
Comparative evaluation of dietary supplementation with mannan oligosaccharide and oregano essential oil in forced molted and fully fed laying hens between 82 and 106 weeks of age.
The aim of this study was to investigate the efficacy of feed-grade preparations of mannan oligosaccharides ( MOS: ) and oregano essential oil ( OEO: ) in forced molted or fully fed 82-week-old, laying hens. A 2 × 3 factorial experiment investigated the influence of molting vs. full feeding and dietary supplements [i.e., unsupplemented control, MOS (1 g/kg) diet, and OEO (24 mg/kg) diet] on production parameters, egg quality, serum stress indicators, blood constituents, tibial characteristics, liver antioxidant status, and cecal microflora composition. A total of 864 Single Comb White Leghorn hens were randomly assigned to 6 treatments, each with 6 replicates of 24 hens each, and studied for 25 wk. Hens were fed a molt diet containing of 50% alfalfa and 50% wheat bran ( AA+WB: ) for 12 d, then returned to the laying ration. Results indicate that molt vs. full feed impacted more on most variables measured than supplementation or supplement type. Significant (P < 0.01) interactions between molting and diet were observed for the egg production, egg weight, egg mass, and feed conversion ratio ( FCR: ). In fully fed hens, MOS supplementation improved (P < 0.01) the egg production, egg weight, and FCR, and an OEO addition significantly improved the egg production and FCR in forced molted hens. Molting improved egg quality despite the significant regression in ovary and oviduct weight (P < 0.01), though supplements showed no influence. The bone ash (P < 0.01) and mineral content (P < 0.05) of molted hens were significantly lower than those of fully fed counterparts; however, poor mineralization was not reflected in the bones' mechanical properties. No significant differences were observed among treatments for hematological characteristics. Both the MOS and particularly the OEO supplementation improved (P < 0.01) liver antioxidant status and mitigated the significant increase in cecal pathogenic bacteria after molt. Our results indicate that full feeding with an aa+wb diet is an effective non-feed-removal method for molted hens, the benefit of which can be improved with MOS and OEO supplementation.
Topics: Animal Feed; Animals; Chickens; Diet; Female; Mannans; Molting; Oils, Volatile; Oligosaccharides; Origanum; Prebiotics; Random Allocation
PubMed: 27143766
DOI: 10.3382/ps/pew140 -
Philosophical Transactions of the Royal... Oct 2019The three modes of insect postembryonic development are ametaboly, hemimetaboly and holometaboly, the latter being considered the only significant metamorphosis mode....
The three modes of insect postembryonic development are ametaboly, hemimetaboly and holometaboly, the latter being considered the only significant metamorphosis mode. However, the emergence of hemimetaboly, with the genuine innovation of the final moult, represents the origin of insect metamorphosis and a necessary step in the evolution of holometaboly. Hemimetaboly derives from ametaboly and might have appeared as a consequence of wing emergence in Pterygota, in the early Devonian. In extant insects, the final moult is mainly achieved through the degeneration of the prothoracic gland (PG), after the formation of the winged and reproductively competent adult stage. Metamorphosis, including the formation of the mature wings and the degeneration of the PG, is regulated by the MEKRE93 pathway, through which juvenile hormone precludes the adult morphogenesis by repressing the expression of transcription factor E93, which triggers this change. The MEKRE93 pathway appears conserved in extant metamorphosing insects, which suggest that this pathway was operative in the Pterygota last common ancestor. We propose that the final moult, and the consequent hemimetabolan metamorphosis, is a monophyletic innovation and that the role of E93 as a promoter of wing formation and the degeneration of the PG was mechanistically crucial for their emergence. This article is part of the theme issue 'The evolution of complete metamorphosis'.
Topics: Animals; Biological Evolution; Insecta; Molting
PubMed: 31438822
DOI: 10.1098/rstb.2018.0415 -
and Promote the Degradation of Serosal and Pro-Nymphal Cuticles during Locust Embryonic Development.Biology Dec 2022The success of the degradation of the extraembryonic serosal cuticle and the second embryonic cuticle (pro-nymphal cuticle) is essential for the development and molting...
The success of the degradation of the extraembryonic serosal cuticle and the second embryonic cuticle (pro-nymphal cuticle) is essential for the development and molting of nymph from egg in Orthoptera . Chitinase 5 is an important gene for chitin degradation in nymphs and in the egg stage. In this study, we investigated the important roles of chitinase 5-1 () and chitinase 5-2 () in the degradation of the serosal and pro-nymphal cuticles during locust embryonic development. The serosal cuticle degrades from 7-day-old embryos (E7) to E13, along with the degradation of the pro-nymphal cuticle, which begins at E12 to E14. The mRNA and protein of and are expressed during the degradation process of the serosal cuticle and the pro-nymphal cuticle. RNAi experiments at the embryonic stage show that both ds and ds contribute to the failure of development in early and late embryogenesis. Further, during the serosal cuticle molting process, ultra-structure analysis indicated that ds prevented the loss of the coarse chitin layer in the upper part in both early and late embryogenesis. Meanwhile, ds blocked the degradation of the lower fine chitin layer at the early stage and blocked the chitin degradation of loose coarse chitin in the late molting process. During the degradation of the pro-nymphal cuticle, ds suppresses chitin degradation between layers in the procuticle, while ds suppresses chitin degradation into filaments inside of the layer. In summary, our results suggest that both and contribute to the degradation of the serosal and pro-nymphal cuticles during the locust embryonic stage.
PubMed: 36552286
DOI: 10.3390/biology11121778 -
PLoS Genetics Feb 2020Endocytosis, the process by which cells internalize plasma membrane and associated cargo, is regulated extensively by posttranslational modifications. Previous studies...
Endocytosis, the process by which cells internalize plasma membrane and associated cargo, is regulated extensively by posttranslational modifications. Previous studies suggested the potential involvement of scores of protein kinases in endocytic control, of which only a few have been validated in vivo. Here we show that the conserved NIMA-related kinases NEKL-2/NEK8/9 and NEKL-3/NEK6/7 (the NEKLs) control clathrin-mediated endocytosis in C. elegans. Loss of NEKL-2 or NEKL-3 activities leads to penetrant larval molting defects and to the abnormal localization of trafficking markers in arrested larvae. Using an auxin-based degron system, we also find that depletion of NEKLs in adult-stage C. elegans leads to gross clathrin mislocalization and to a dramatic reduction in clathrin mobility at the apical membrane. Using a non-biased genetic screen to identify suppressors of nekl molting defects, we identified several components and regulators of AP2, the major clathrin adapter complex acting at the plasma membrane. Strikingly, reduced AP2 activity rescues both nekl mutant molting defects as well as associated trafficking phenotypes, whereas increased levels of active AP2 exacerbate nekl defects. Moreover, in a unique example of mutual suppression, NEKL inhibition alleviates defects associated with reduced AP2 activity, attesting to the tight link between NEKL and AP2 functions. We also show that NEKLs are required for the clustering and internalization of membrane cargo required for molting. Notably, we find that human NEKs can rescue molting and trafficking defects in nekl mutant worms, suggesting that the control of intracellular trafficking is an evolutionarily conserved function of NEK family kinases.
Topics: Adaptor Protein Complex 2; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Cell Membrane; Clathrin; Endocytosis; Intravital Microscopy; Larva; Molting; Mutation; NIMA-Related Kinases; Protein Kinases; Recombinant Proteins; Time-Lapse Imaging
PubMed: 32069276
DOI: 10.1371/journal.pgen.1008633 -
Parasites & Vectors Apr 2016Human babesiosis is considered an emerging threat in China. Dozens of human infections with Babesia microti have been reported recently, especially in southern China....
BACKGROUND
Human babesiosis is considered an emerging threat in China. Dozens of human infections with Babesia microti have been reported recently, especially in southern China. However, the transmission vectors of this parasite in these areas are not well understood. Rhipicephalus haemaphysaloides, which is one of the dominant tick species in southern China, is a major vector of bovine babesiosis in China. However, whether this tick has the potential to transmit B. microti has not been tested. The present study experimentally investigated the transmission competence of B. microti through R. haemaphysaloides ticks.
METHODS
Larvae and nymphs of R. haemaphysaloides ticks were fed on laboratory mice infected by B. microti. The infection was detected by PCR at 4 weeks post-molting. BALB/c and NOD/SCID mice were infested by nymphs molting from larvae that ingested the blood of infective mice, and blood samples were then analyzed by PCR.
RESULTS
Experimental transstadial transmission of R. haemaphysaloides for B. microti was proved in both the larvae to nymph and the nymph to adult transstadial routes. The positive rate of B. microti was 43.8% in nymphs developed from larvae consumed infected mice and 96.7% in adults developed from nymphs exposed to positive mice. Among the mice infested by infective nymphs, B. microti was detected in 16.7% (2/12) of the BALB/c mice and in all of the NOD/SCID (6/6). However, the parasite was not observed to persist beyond more than one molt, and transovarial transmission did not occur.
CONCLUSIONS
This is the first study to demonstrate that B. microti can be transmitted artificially by R. haemaphysaloides. This tick species might be a potential vector of human babesiosis in southern China, which represents a public health concern.
Topics: Animals; Arachnid Vectors; BALB 3T3 Cells; Babesia microti; Babesiosis; Female; Larva; Mice; Mice, SCID; Nymph; Rhipicephalus; Specific Pathogen-Free Organisms
PubMed: 27112141
DOI: 10.1186/s13071-016-1517-2 -
Ecology and Evolution Sep 2020Many species of birds show distinctive seasonal breeding and nonbreeding plumages. A number of hypotheses have been proposed for the evolution of this seasonal...
Many species of birds show distinctive seasonal breeding and nonbreeding plumages. A number of hypotheses have been proposed for the evolution of this seasonal dichromatism, specifically related to the idea that birds may experience variable levels of sexual selection relative to natural selection throughout the year. However, these hypotheses have not addressed the selective forces that have shaped molt, the underlying mechanism of plumage change. Here, we examined relationships between life-history variation, the evolution of a seasonal molt, and seasonal plumage dichromatism in the New World warblers (Aves: Parulidae), a family with a remarkable diversity of plumage, molt, and life-history strategies. We used phylogenetic comparative methods and path analysis to understand how and why distinctive breeding and nonbreeding plumages evolve in this family. We found that color change alone poorly explains the evolution of patterns of biannual molt evolution in warblers. Instead, molt evolution is better explained by a combination of other life-history factors, especially migration distance and foraging stratum. We found that the evolution of biannual molt and seasonal dichromatism is decoupled, with a biannual molt appearing earlier on the tree, more dispersed across taxa and body regions, and correlating with separate life-history factors than seasonal dichromatism. This result helps explain the apparent paradox of birds that molt biannually but show breeding plumages that are identical to the nonbreeding plumage. We find support for a two-step process for the evolution of distinctive breeding and nonbreeding plumages: That prealternate molt evolves primarily under selection for feather renewal, with seasonal color change sometimes following later. These results reveal how life-history strategies and a birds' environment act upon multiple and separate feather functions to drive the evolution of feather replacement patterns and bird coloration.
PubMed: 32953057
DOI: 10.1002/ece3.6606 -
Frontiers in Physiology 2021Anthropogenic elevation of atmospheric carbon dioxide (CO) drives global-scale ocean acidification (OA), which has aroused widespread concern for marine ecosystem...
Anthropogenic elevation of atmospheric carbon dioxide (CO) drives global-scale ocean acidification (OA), which has aroused widespread concern for marine ecosystem health. The tri-spine horseshoe crab (HSC) has been facing the threat of population depletion for decades, and the effects of OA on the physiology and microbiology of its early life stage are unclear. In this study, the 1st instar HSC larvae were exposed to acidified seawater (pH 7.3, pH 8.1 as control) for 28 days to determine the effects of OA on their growth, molting, oxidative stress, and gut microbiota. Results showed that there were no significant differences in growth index and molting rate between OA group and control group, but the chitinase activity, β-NAGase activity, and ecdysone content in OA group were significantly lower than those of the control group. Compared to the control group, reactive oxygen species (ROS) and malondialdehyde (MDA) contents in OA group were significantly increased at the end of the experiment. Superoxide dismutase (SOD), catalase (CAT), and alkaline phosphatase (AKP) activities increased first and then decreased, glutathione peroxidase (GPX) decreased first and then increased, and GST activity changed little during the experiment. According to the result of 16S rRNA sequencing of gut microbiota, microbial-mediated functions predicted by PICRUSt showed that "Hematopoietic cell lineage," "Endocytosis," " infection," and "Shigellosis" pathways significantly increased in OA group. The above results indicate that OA had no significant effect on growth index and molting rate but interfered with the activity of chitinolytic enzymes and ecdysone expression of juvenile horseshoe crabs, and caused oxidative stress. In addition, OA had adverse effects on the immune defense function and intestinal health. The present study reveals the potential threat of OA to population and lays a foundation for the further study of the physiological adaptation mechanism of juvenile horseshoe crabs to environmental change.
PubMed: 35069266
DOI: 10.3389/fphys.2021.813582 -
Physiology & Behavior Feb 2019While endotherms can rely on their insulation to reduce heat loss to adapt to cold environments, renewing of fur during molt impairs insulation while they have to...
While endotherms can rely on their insulation to reduce heat loss to adapt to cold environments, renewing of fur during molt impairs insulation while they have to perfuse the periphery to support epidermal tissues. The southern elephant seal Mirounga leonina undertakes an annual catastrophic molt while fasting on land in a wet, windy and cold environment. However, southern elephant seals show characteristic aggregation patterns that are predicted to reduce high metabolic costs during the molt. Between 2012 and 2016, 59 female elephant seals were tracked on land during their molt to study their aggregation behavior in relation to molt stage, habitat type and local weather conditions. Infrared thermography and stomach temperature loggers were used to observe variation in body surface and internal temperature in relation to molt stage and aggregation behavior. We found that thermal constraints varied during the molt, with a peak in surface temperature during the mid-stage of the molt. Wallows (mud pools) appear as favorable habitat to aggregate while molting. Indeed, wallows offered a warmer microclimate with greater ground temperature and lower wind speed. Moreover, there was a greater proportion of aggregated seals and larger group size in wallows. These aggregation patterns in wallows were influenced by local weather such that a greater proportion of seals were located in the center of the aggregation, and larger group size occurred during days of unfavorable meteorological conditions. We also observed a higher proportion of seals at mid-stage of molt amongst aggregated seals compared to isolated individuals. This aggregation behavior may reduce the cost of thermogenesis as surface body temperature and stomach temperature were cooler by 1.0 °C and 1.5 °C, respectively, in aggregated compared to isolated seals. As a consequence, huddling behavior may be thermally advantageous for female southern elephant seals during the molt.
Topics: Animals; Behavior, Animal; Body Temperature; Body Temperature Regulation; Ecosystem; Environment; Female; Molting; Seals, Earless; Temperature
PubMed: 30385351
DOI: 10.1016/j.physbeh.2018.10.016 -
PloS One 2022The steroid hormone 20-hydroxyecdysone (20E) controls molting in arthropods. The timing of 20E production, and subsequent developmental transitions, is influenced by a...
The steroid hormone 20-hydroxyecdysone (20E) controls molting in arthropods. The timing of 20E production, and subsequent developmental transitions, is influenced by a variety of environmental factors including nutrition, photoperiod, and temperature, which is particularly relevant in the face of climate change. Environmental changes, combined with rapid urbanization, and the increasing prevalence of urban heat islands (UHI) have contributed to an overall decrease in biodiversity making it critical to understand how organisms respond to elevating global temperatures. Some arthropods, such as the Western black widow spider, Latrodectus hesperus, appear to thrive under UHI conditions, but the physiological mechanism underlying their success has not been explored. Here we examine the relationship between hemolymph 20E titers and spiderling development under non-urban desert (27°C), intermediate (30°C), and urban (33°C) temperatures. We found that a presumptive molt-inducing 20E peak observed in spiders at non-urban desert temperatures was reduced and delayed at higher temperatures. Intermolt 20E titers were also significantly altered in spiders reared under UHI temperatures. Despite the apparent success of black widows in urban environments, we noted that, coincident with the effects on 20E, there were numerous negative effects of elevated temperatures on spiderling development. The differential effects of temperature on pre-molt and intermolt 20E titers suggest distinct hormonal mechanisms underlying the physiological, developmental, and behavioral response to heat, allowing spiders to better cope with urban environments.
Topics: Animals; Black Widow Spider; Cities; Ecdysteroids; Hot Temperature; Urbanization
PubMed: 35482802
DOI: 10.1371/journal.pone.0267398