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Environmental Science & Technology Nov 2020The densely populated North Sea region encompasses catchments of rivers such as Scheldt and Meuse. Herein, agricultural, industrial, and household chemicals are emitted,...
The densely populated North Sea region encompasses catchments of rivers such as Scheldt and Meuse. Herein, agricultural, industrial, and household chemicals are emitted, transported by water, and deposited in sediments, posing ecological risks. Though sediment monitoring is often costly and time-intensive, modeling its toxicity to biota has received little attention. Due to high complexity of interacting variables that induce overall toxicity, monitoring data only sporadically validates current models. Via a range of concepts, we related bio-physicochemical constituents of sediment in Flanders to results from toxicity bioassays performed on the ostracod . Depending on the water body, we explain up to 90% of the variance in growth. Though variable across Flanders' main water bodies, organotin cations and ammonia dominate the observed toxicity according to toxic unit (TU) assessments. Approximately 10% relates to testing conditions/setups, species variabilities, incoherently documented pollutant concentrations, and/or bio-physicochemical sediment properties. We elucidated the influence of organotin cations and ammonia relative to other metal(oxides) and biocides. Surprisingly, the tributylin cation appeared ∼1000 times more toxic to as compared to "single-substance" bioassays for similar species. We inferred indirect mixture effects between organotin, ammonia, and phosphate. Via chemical speciation calculations, we observed strong physicochemical and biological interactions between phosphate and organotin cations. These interactions enhance bioconcentration and explain the elevated toxicity of organotin cations. Our study aids water managers and policy makers to interpret monitoring data on a mechanistic basis. As sampled sediments differ, future modeling requires more emphasis on characterizing and parametrizing the interactions between bioassay constituents. We envision that this will aid in bridging the gap between testing in the laboratory and field observations.
Topics: Animals; Bioaccumulation; Cations; Crustacea; Environmental Monitoring; Geologic Sediments; Molting; North Sea; Toxicity Tests; Water Pollutants, Chemical
PubMed: 33135409
DOI: 10.1021/acs.est.0c02855 -
PLoS Neglected Tropical Diseases Oct 2022Pyruvate kinase widely exists in many parasites and plays an important role in the energy production for the parasites. Pyruvate kinase might be a potential drug target...
BACKGROUND
Pyruvate kinase widely exists in many parasites and plays an important role in the energy production for the parasites. Pyruvate kinase might be a potential drug target for killing the parasites. The aim of the present study was to evaluate the biological characteristics and roles of T. spiralis pyruvate kinase M (TsPKM) in sugar metabolism, larval molting and development of T. spiralis.
METHODOLOGY/PRINCIPAL FINDINGS
TsPKM has two functional domains of pyruvate kinase and the tertiary structure of TsPKM is tetramer which has the enzyme active site constituted by 8 amino-acid residues (Arg71, Asn73, Asp110, Phe241, Lys267, Glu269, Asp293 and Thr325). Recombinant TsPKM (rTsPKM) was expressed and purified. The rTsPKM had good immunogenicity. RT-PCR and Western blot showed that TsPKM was transcribed and expressed at various developmental stages in T. spiralis lifecycle. Immunofluorescence test showed that TsPKM was principally located in the cuticle, muscle, stichosome, intestine and the intrauterine embryos of female adults. rTsPKM catalyzed the reaction of phosphoenolpyruvate (PEP) and adenosine diphosphate (ADP) to produce pyruvic acid and adenosine triphosphate (ATP). TsPKM played an important role in the metabolism and energy production of T. spiralis. After silencing of TsPKM gene by specific dsRNA-TsPKM2, protein expression and enzyme activity of TsPKM decreased by 50.91 and 26.06%, respectively. After treatment with RNAi, natural TsPKM enzyme activity, larval molting, sugar metabolism, growth and development of T. spiralis were significantly reduced.
CONCLUSIONS
TsPKM participates in the larval molting, sugar metabolism, growth and development of T. spiralis and it might be a candidate target of therapeutic drug of trichinellosis.
Topics: Animals; Female; Mice; Trichinella spiralis; Pyruvate Kinase; Larva; Molting; Trichinellosis; Parasites; Sugars; Mice, Inbred BALB C; Helminth Proteins
PubMed: 36315477
DOI: 10.1371/journal.pntd.0010881 -
Frontiers in Cellular and Infection... 2020Additional research on soft ticks in the family Argasidae is needed to bridge the knowledge gap relative to hard ticks of the family Ixodidae; especially, the molecular...
Additional research on soft ticks in the family Argasidae is needed to bridge the knowledge gap relative to hard ticks of the family Ixodidae; especially, the molecular mechanisms of biology. species are vectors of human and animal pathogens that include tick-borne relapsing fever spirochetes and African swine fever virus. Soft tick vector-pathogen interactions involving components of the tick immune response are not understood. Ticks utilize a basic innate immune system consisting of recognition factors and cellular and humoral responses to produce antimicrobial peptides, like defensins. In the present study, we identified and characterized the first putative defensins of , an argasid tick found primarily in the southwestern United States and regions of Latin America. Four genes (, and ) were identified through sequencing and their predicted amino acid sequences contained motifs characteristic of arthropod defensins. A phylogenetic analysis grouped these four genes with arthropod defensins, and computational structural analyses further supported the identification. Since pathogens transmitted by colonize both the midgut and salivary glands, expression patterns of the putative defensins were determined in these tissues 1 week post engorgement and after molting. Defensin genes up-regulated in the tick midgut 1 week post blood feeding were and , while was up-regulated in the midgut of post-molt ticks. Moreover, and were also up-regulated in the salivary glands of flat post-molt ticks, while was up-regulated within 1 week post blood-feeding. This work is foundational toward additional studies to determine mechanisms of vector competence and pathogen transmission from .
Topics: Animals; Arthropod Proteins; Defensins; Eating; Ornithodoros; Phylogeny
PubMed: 32477960
DOI: 10.3389/fcimb.2020.00152 -
PLoS Neglected Tropical Diseases Jun 2020Filarial nematodes can cause debilitating diseases in humans. They have complicated life cycles involving an insect vector and mammalian hosts, and they go through a...
Filarial nematodes can cause debilitating diseases in humans. They have complicated life cycles involving an insect vector and mammalian hosts, and they go through a number of developmental molts. While whole genome sequences of parasitic worms are now available, very little is known about transcription factor (TF) binding sites and their cognate transcription factors that play a role in regulating development. To address this gap, we developed a novel motif prediction pipeline, Emotif Alpha, that integrates ten different motif discovery algorithms, multiple statistical tests, and a comparative analysis of conserved elements between the filarial worms Brugia malayi and Onchocerca volvulus, and the free-living nematode Caenorhabditis elegans. We identified stage-specific TF binding motifs in B. malayi, with a particular focus on those potentially involved in the L3-L4 molt, a stage important for the establishment of infection in the mammalian host. Using an in vitro molting system, we tested and validated three of these motifs demonstrating the accuracy of the motif prediction pipeline.
Topics: Animals; Base Sequence; Brugia malayi; Caenorhabditis elegans; Gene Expression Profiling; Genes, Helminth; Larva; Molting; Oligonucleotide Array Sequence Analysis; Onchocerca volvulus; RNA, Helminth; Transcription Factors
PubMed: 32574217
DOI: 10.1371/journal.pntd.0008275 -
Developmental Biology Sep 2016In contrast with Drosophila melanogaster, practically nothing is known about the involvement of the TGF-β signaling pathway in the metamorphosis of hemimetabolan...
In contrast with Drosophila melanogaster, practically nothing is known about the involvement of the TGF-β signaling pathway in the metamorphosis of hemimetabolan insects. To partially fill this gap, we have studied the role of Smad factors in the metamorphosis of the German cockroach, Blattella germanica. In D. melanogaster, Mad is the canonical R-Smad of the BMP branch of the TGF-β signaling pathway, Smox is the canonical R-Smad of the TGF-β/Activin branch and Medea participates in both branches. In insects, metamorphosis is regulated by the MEKRE93 pathway, which starts with juvenile hormone (JH), whose signal is transduced by Methoprene-tolerant (Met), which stimulates the expression of Krüppel homolog 1 (Kr-h1) that acts to repress E93, the metamorphosis trigger. In B. germanica, metamorphosis is determined at the beginning of the sixth (final) nymphal instar (N6), when JH production ceases, the expression of Kr-h1 declines, and the transcription of E93 begins to increase. The RNAi of Mad, Smox and Medea in N6 of B. germanica reveals that the BMP branch of the TGF-β signaling pathway regulates adult ecdysis and wing extension, mainly through regulating the expression of bursicon, whereas the TGF-β/Activin branch contributes to increasing E93 and decreasing Kr-h1 at the beginning of N6, crucial for triggering adult morphogenesis, as well as to regulating the imaginal molt timing.
Topics: Activins; Animals; Bone Morphogenetic Proteins; Cockroaches; DNA-Binding Proteins; Drosophila Proteins; Drosophila melanogaster; Gene Expression Regulation, Developmental; Juvenile Hormones; Kruppel-Like Transcription Factors; Metamorphosis, Biological; Molting; RNA Interference; RNA, Small Interfering; Signal Transduction; Smad Proteins; Smad Proteins, Receptor-Regulated; Smad4 Protein; Transcription Factors; Transforming Growth Factor beta
PubMed: 27452629
DOI: 10.1016/j.ydbio.2016.07.006 -
Scientific Reports Nov 2019Ecdysteroids (arthropod molting hormones) play an important role in the development and sexual maturation of arthropods, and they have been shown to have anabolic and...
Ecdysteroids (arthropod molting hormones) play an important role in the development and sexual maturation of arthropods, and they have been shown to have anabolic and "energizing" effect in higher vertebrates. The aim of this study was to assess ecdysteroid diversity, levels according to bird species and months, as well as to observe the molting status of hard ticks (Acari: Ixodidae) infesting the birds. Therefore, blood samples and ticks were collected from 245 birds (244 songbirds and a quail). Mass spectrometric analyses showed that 15 ecdysteroids were regularly present in the blood samples. Molting hormones biologically most active in insects (including 20-hydroxyecdysone [20E], 2deoxy-20E, ajugasterone C and dacryhainansterone) reached different levels of concentration according to bird species and season. Similarly to ecdysteroids, the seasonal presence of affected, apolytic ticks peaked in July and August. In conclusion, this study demonstrates the presence of a broad range and high concentrations of ecdysteroids in the blood stream of wild-living passerine birds. These biologically active, anabolic compounds might possibly contribute to the known high metabolic rate of songbirds.
Topics: Animals; Animals, Wild; Arthropods; Ecdysone; Ecdysteroids; Ecdysterone; Host-Parasite Interactions; Ixodidae; Molecular Structure; Molting; Seasons; Songbirds; Species Specificity
PubMed: 31740690
DOI: 10.1038/s41598-019-53090-9 -
Chitinase (CHI) of affects molting development by regulating the metabolism of chitin and trehalose.Frontiers in Physiology 2022Chitin is the main component of insect exoskeleton and midgut peritrophic membrane. Insect molting is the result of the balance and coordination of chitin synthesis and...
Chitin is the main component of insect exoskeleton and midgut peritrophic membrane. Insect molting is the result of the balance and coordination of chitin synthesis and degradation in chitin metabolism under the action of hormones. In this study, a 678 bp dsRNA fragment was designed and synthesized according to the known CHI (Chitinase) sequence of . It was injected into the larvae to observe the molting and development of . At the same time, the activities of trehalase and chitinase, the contents of trehalose, chitin and other substances were detected, and the expression of related genes in the chitin synthesis pathway was determined. The results showed that gene was highly expressed at the end of each instar, prepupa and pupal stage before molting; At 12 and 24 h after dsRNA injection of gene of , the expression of gene decreased significantly, and the chitinase activity decreased significantly from 12 to 48 h. The expression of chitin synthase () gene decreased significantly, and the chitin content increased significantly. Some larvae could not molt normally and complete development, leading to certain mortality. Secondly, after RNAi of gene, the content of glucose and glycogen increased first and then decreased, while the content of trehalose decreased significantly or showed a downward trend. The activities of the two types of trehalase and the expression levels of trehalase genes decreased first and then increased, especially the trehalase activities increased significantly at 48 h after dsCHI injection. And trehalose-6-phosphate synthase (), glutamine: fructose-6-phosphate amidotransferase (), UDP-N-acetylglucosamine pyrophosphorylases (), hexokinase (), glucose-6-phosphate isomerase () and phosphoacetylglucosamine mutase () all decreased significantly at 24 h, and then increased or significantly increased at 48 h. These results indicated that when the expression of chitinase gene of was inhibited, it affected the degradation of chitin in the old epidermis and the formation of new epidermis, and the content of chitin increased, which led to the failure of larvae to molt normally. Moreover, the chitin synthesis pathway and trehalose metabolism were also regulated. The relevant results provide a theoretical basis for screening target genes and developing green insecticides to control pests by using the chitin metabolism pathway.
PubMed: 36262255
DOI: 10.3389/fphys.2022.1034926 -
Current Biology : CB Feb 2021Animals with exoskeletons molt for further growth. In insects, the number of larval (or nymphal) molts varies inter- and intra-specifically, and it is widely accepted...
Animals with exoskeletons molt for further growth. In insects, the number of larval (or nymphal) molts varies inter- and intra-specifically, and it is widely accepted that the variation in the number of larval molts is an adaptive response to diverse environmental conditions. However, the molecular mechanism that underlies the variety and plasticity in the number of larval molts is largely unknown. In the silkworm, Bombyx mori, there are strains that molt three, four, or five times, and these numbers are determined by allelic variation at a single autosomal locus, Moltinism (M). Here, we demonstrate that the Hox gene Sex combs reduced (Scr) is responsible for the phenotypes of the M locus. Scr is selectively expressed in the larval prothoracic gland (PG), an endocrine organ that produces molting hormones.Scr represses the biosynthesis of molting hormones in the PG, thereby regulating the incremental increase in body size during each larval instar. Our experiments consistently suggest that the differential expression levels of Scr among the three M alleles result in different growth ratios that ultimately lead to the different number of larval molts. Although the role of Hox genes in conferring segmental identity along the body axis and in molding segment-specific structure later in development has been well established, the present study identifies an unexpected role of Hox gene in hormone biosynthesis. This new role means that, in addition to shaping segment-specific morphology, Hox genes also drive the evolution of life history traits by regulating animal physiology.
Topics: Animals; Bombyx; Ecdysone; Larva; Molting; Phenotype
PubMed: 33308417
DOI: 10.1016/j.cub.2020.11.017 -
Current Biology : CB Jan 2021Ecdysis or molting evolved ∼535 mya in Ecdysozoa, the most diverse and species-rich animal superphylum. A cascade of ecdysis-related neuropeptides (ERNs) controls the...
Ecdysis or molting evolved ∼535 mya in Ecdysozoa, the most diverse and species-rich animal superphylum. A cascade of ecdysis-related neuropeptides (ERNs) controls the innate behavioral programs required for cuticle shedding in some ecdysozoan lineages (e.g., arthropods) but is lacking in others (e.g., nematodes). We recently reported on the surprisingly ancient bilaterian origin of key ERNs, such as eclosion hormone (EH), crustacean cardioactive neuropeptide (CCAP), myoinhibitory peptide (MIP), bursicon alpha (Bursα), and bursicon beta (Bursβ). Thus, ERNs far predate the emergence of ecdysis, but the question as to their ancestral functions remains unresolved. Here, we compare the ERN toolkits and temporal expression profiles of six ecdysozoans (tardigrades, crustaceans, and insects), eight lophotrochozoans (planarians, annelids, and mollusks), and five deuterostomes (crinoids, sea urchins, and hemichordates). Our results show that the major, coordinated upregulation of ERNs always coincides with a transition between key life history stages, such as hatching in direct developers and metamorphosis in indirect developers. This implies that ERNs already played an ancestral role in the switch from embryonic or larval ontogeny to juvenile maturation in the last common ancestor of Nephrozoa. Consequently, the transcriptional signature of invertebrate life cycle transitions presented here was already in place in the Precambrian and was only secondarily co-opted into regulating the molting process at the dawn of Ecdysozoa.
Topics: Animals; Biological Evolution; Life Cycle Stages; Molting; Neuropeptides
PubMed: 33125864
DOI: 10.1016/j.cub.2020.10.004 -
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