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1.
Sci Rep ; 12(1): 9489, 2022 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-35676286

RESUMO

The population of the Endangered African penguin Spheniscus demersus has decreased by > 65% in the last 20 years. A major driver of this decrease has been the reduced availability of their principal prey, sardine Sardinops sagax and anchovy Engraulis encrasicolus. To date, conservation efforts to improve prey availability have focused on spatial management strategies to reduce resource competition with purse-seine fisheries during the breeding season. However, penguins also undergo an annual catastrophic moult when they are unable to feed for several weeks. Before moulting they must accumulate sufficient energy stores to survive this critical life-history stage. Using GPS tracking data collected between 2012 and 2019, we identify important foraging areas for pre- and post-moult African penguins at three of their major colonies in South Africa: Dassen Island and Stony Point (Western Cape) and Bird Island (Eastern Cape). The foraging ranges of pre- and post-moult adult African penguins (c. 600 km from colony) was far greater than that previously observed for breeding penguins (c. 50 km from colony) and varied considerably between sites, years and pre- and post-moult stages. Despite their more extensive range during the non-breeding season, waters within 20 and 50 km of their breeding colonies were used intensively and represent important foraging areas to pre- and post-moult penguins. Furthermore, penguins in the Western Cape travelled significantly further than those in the Eastern Cape which is likely a reflection of the poor prey availability along the west coast of South Africa. Our findings identify important marine areas for pre- and post-moult African penguins and support for the expansion of fisheries-related spatio-temporal management strategies to help conserve African penguins outside the breeding season.


Assuntos
Spheniscidae , Animais , Pesqueiros , Peixes , Muda , Estações do Ano
2.
Cutis ; 109(4): 221-223, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35659851

RESUMO

Blisters and subsequent desquamation of the skin in the presence of acute edema is a well-known clinical phenomenon. In this case report, we describe a new variant that we have termed anasarca-induced desquamation in a 50-year-old man with molting of the entire cutaneous surface after acute edema, in a setting of 40-lb weight gain over 5 days. Laboratory workup for infectious causes and punch biopsies of skin lesions ruled out Stevens-Johnson syndrome and staphylococcal scalded skin syndrome, which have a similar clinical presentation to anasarca-induced desquamation. In patients with diffuse superficial desquamation in the setting of acute edema, anasarca-induced desquamation is worth investigating to avoid the use of corticosteroids and intravenous antibiotics in this inherently benign condition.


Assuntos
Síndrome da Pele Escaldada Estafilocócica , Síndrome de Stevens-Johnson , Edema/diagnóstico , Edema/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Muda , Pele/patologia , Síndrome de Stevens-Johnson/etiologia
3.
Nat Commun ; 13(1): 3132, 2022 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-35668054

RESUMO

Animals increase by orders of magnitude in volume during development. Therefore, small variations in growth rates among individuals could amplify to a large heterogeneity in size. By live imaging of C. elegans, we show that amplification of size heterogeneity is prevented by an inverse coupling of the volume growth rate to the duration of larval stages and does not involve strict size thresholds for larval moulting. We perturb this coupling by changing the developmental tempo through manipulation of a transcriptional oscillator that controls the duration of larval development. As predicted by a mathematical model, this perturbation alters the body volume. Model analysis shows that an inverse relation between the period length and the growth rate is an intrinsic property of genetic oscillators and can occur independently of additional complex regulation. This property of genetic oscillators suggests a parsimonious mechanism that counteracts the amplification of size differences among individuals during development.


Assuntos
Caenorhabditis elegans , Muda , Animais , Tamanho Corporal , Caenorhabditis elegans/genética , Larva/genética , Modelos Teóricos
4.
Commun Biol ; 5(1): 518, 2022 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-35641660

RESUMO

Microbial lytic polysaccharide monooxygenases (LPMOs) catalyze the oxidative cleavage of crystalline polysaccharides including chitin and cellulose. The discovery of a large assortment of LPMO-like proteins widely distributed in insect genomes suggests that they could be involved in assisting chitin degradation in the exoskeleton, tracheae and peritrophic matrix during development. However, the physiological functions of insect LPMO-like proteins are still undetermined. To investigate the functions of insect LPMO15 subgroup I-like proteins (LPMO15-1s), two evolutionarily distant species, Tribolium castaneum and Locusta migratoria, were chosen. Depletion by RNAi of T. castaneum TcLPMO15-1 caused molting arrest at all developmental stages, whereas depletion of the L. migratoria LmLPMO15-1, prevented only adult eclosion. In both species, LPMO15-1-deficient animals were unable to shed their exuviae and died. TEM analysis revealed failure of turnover of the chitinous cuticle, which is critical for completion of molting. Purified recombinant LPMO15-1-like protein from Ostrinia furnacalis (rOfLPMO15-1) exhibited oxidative cleavage activity and substrate preference for chitin. These results reveal the physiological importance of catalytically active LPMO15-1-like proteins from distant insect species and provide new insight into the enzymatic mechanism of cuticular chitin turnover during molting.


Assuntos
Quitina , Oxigenases de Função Mista , Animais , Quitina/metabolismo , Carboidratos da Dieta , Insetos , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Muda , Polissacarídeos/metabolismo
5.
PLoS Genet ; 18(5): e1010249, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35639786

RESUMO

Molting is a widespread developmental process in which the external extracellular matrix (ECM), the cuticle, is remodeled to allow for organismal growth and environmental adaptation. Studies in the nematode Caenorhabditis elegans have identified a diverse set of molting-associated factors including signaling molecules, intracellular trafficking regulators, ECM components, and ECM-modifying enzymes such as matrix metalloproteases. C. elegans NEKL-2 and NEKL-3, two conserved members of the NEK family of protein kinases, are essential for molting and promote the endocytosis of environmental steroid-hormone precursors by the epidermis. Steroids in turn drive the cyclic induction of many genes required for molting. Here we report a role for the sole C. elegans ADAM-meltrin metalloprotease family member, ADM-2, as a mediator of molting. Loss of adm-2, including mutations that disrupt the metalloprotease domain, led to the strong suppression of molting defects in partial loss-of-function nekl mutants. ADM-2 is expressed in the epidermis, and its trafficking through the endo-lysosomal network was disrupted after NEKL depletion. We identified the epidermally expressed low-density lipoprotein receptor-related protein, LRP-1, as a candidate target of ADM-2 regulation. Whereas loss of ADM-2 activity led to the upregulation of apical epidermal LRP-1, ADM-2 overexpression caused a reduction in LRP-1 levels. Consistent with this, several mammalian ADAMs, including the meltrin ADAM12, have been shown to regulate mammalian LRP1 via proteolysis. In contrast to mammalian homologs, however, the regulation of LRP-1 by ADM-2 does not appear to involve the metalloprotease function of ADM-2, nor is proteolytic processing of LRP-1 strongly affected in adm-2 mutants. Our findings suggest a noncanonical role for an ADAM family member in the regulation of a lipoprotein-like receptor and lead us to propose that endocytic trafficking may be important for both the internalization of factors that promote molting as well as the removal of proteins that can inhibit the process.


Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Animais , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Endocitose/genética , Mamíferos/metabolismo , Metaloproteases/genética , Metaloproteases/metabolismo , Muda/genética
6.
Int J Mol Sci ; 23(7)2022 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-35409210

RESUMO

The insect glycoside hydrolase family 20 ß-N-acetylhexosaminidases (HEXs) are key enzymes involved in chitin degradation. In this study, nine HEX genes in Bombyx mori were identified by genome-wide analysis. Bioinformatic analysis based on the transcriptome database indicated that each gene had a distinct expression pattern. qRT-PCR was performed to detect the expression pattern of the chitooligosaccharidolytic ß-N-acetylglucosaminidase (BmChiNAG). BmChiNAG was highly expressed in chitin-rich tissues, such as the epidermis. In the wing disc and epidermis, BmChiNAG has the highest expression level during the wandering stage. CRISPR/Cas9-mediated BmChiNAG deletion was used to study the function. In the BmChiNAG-knockout line, 39.2% of female heterozygotes had small and curly wings. The ultrastructure of a cross-section showed that the lack of BmChiNAG affected the stratification of the wing membrane and the formation of the correct wing vein structure. The molting process of the homozygotes was severely hindered during the larva to pupa transition. Epidermal sections showed that the endocuticle of the pupa was not degraded in the mutant. These results indicate that BmChiNAG is involved in chitin catabolism and plays an important role in the molting and wing development of the silkworm, which highlights the potential of BmChiNAG as a pest control target.


Assuntos
Bombyx , Animais , Bombyx/metabolismo , Quitina/metabolismo , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Larva/genética , Larva/metabolismo , Muda/genética , Pupa
7.
Pestic Biochem Physiol ; 183: 105083, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35430073

RESUMO

Metformin, considered to be a potent AMPK activator, is widely used for clinical therapy of cancer and diabetes due to its distinct function in regulating cell energy balance and body metabolism. However, the effect of metformin-induced AMPK activation on the growth and development of insects remains largely unknown. In the present study, we focused on the role of metformin in regulating the growth and development of Hyphantria cunea, a notorious defoliator in the forestry. Firstly, we obtained the complete coding sequences of HcAMPKα2, HcAMPKß1, HcAMPKγ2 from H. cunea, which encoded a protein of 512, 281, and 680 amino acids respectively. Furthermore, the phylogenetic analysis revealed that these three subunits were highly homologous with the AMPK subunits from other lepidopteran species. According to the bioassay, we found metformin remarkably restrained the growth and development of H. cunea larvae, and caused molting delayed and body weight reduced. In addition, expressions of HcAMPKα2, HcAMPKß1, and HcAMPKγ2 were upregulated 3.30-, 5.93- and 5.92-folds at 24 h after treatment, confirming that metformin activated AMPK signaling at the transcriptional level in H. cunea larvae. Conversely, the expressions of two vital Halloween genes (HcCYP306A1 and HcCYP314A1) in the 20E synthesis pathway were remarkably suppressed by metformin. Thus, we presumed that metformin delayed larval molting probably by impeding 20E synthesis in the H. cunea larvae. Finally, we found that metformin accelerated glycogen breakdown, elevated in vivo trehalose level, promoted chitin synthesis, and upregulated transcriptions of the genes in chitin synthesis pathway. Taken together, the findings provide a new insight into the molecular mechanisms by which AMPK regulates carbohydrate metabolism and chitin synthesis in insects.


Assuntos
Metformina , Mariposas , Proteínas Quinases Ativadas por AMP/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Quitina/metabolismo , Larva/metabolismo , Metformina/metabolismo , Metformina/farmacologia , Muda , Mariposas/genética , Filogenia
8.
Dev Biol ; 486: 96-108, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35367457

RESUMO

Skin epidermis secretes apical extracellular matrix (aECM) as a protective barrier from the external environment. The aECM is highly dynamic and constantly undergoes remodeling during animal development. How aECM dynamics is temporally regulated during development, and whether and how its mis-regulation may impact epidermal cell morphology or function remains to be fully elucidated. Here, we report that the conserved Zn-finger transcription factor BLMP-1/Blimp1, which regulates epidermal development in C. elegans, controls apical cell shape of the epidermis by downregulation of aECM remodeling. Loss of blmp-1 causes upregulation of genes essential for molting, including bus-8 and mlt-8, in adult, leading to an abnormal shape in the apical region of adult epidermal cells. The apical epidermal morphological defect is suppressed by reduction of bus-8 or mlt-8. BUS-8 is a key mannosyltransferase, which functions in glycosylation of N-linked glycoproteins; MLT-8 has a ganglioside GM2 lipid-binding domain and is implicated in signaling during molting, a process where the old cuticle is shed and synthesized anew. Overexpression of bus-8 or mlt-8 induces an apical epidermal cell defect as observed in blmp-1 mutants. MLT-8::GFP fusion protein is localized to lysosomes and secreted to aECM. BUS-8 is important for MLT-8 stability and lysosomal targeting, which may be regulated by BUS-8-mediated glycosylation of MLT-8 and function as a molting signaling cue in aECM remodeling. We propose that BLMP-1 represses MLT-8 expression and glycosylation in the epidermis to prevent inappropriate aECM remodeling, which is essential for maintenance of apical epidermal cell morphology during larva-to-adult transition.


Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Animais , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Células Epidérmicas/metabolismo , Epiderme/metabolismo , Manosiltransferases/metabolismo , Muda/genética
9.
Aquat Toxicol ; 247: 106172, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35468410

RESUMO

In aquatic arthropods, molting is a pivotal physiological process for normal development, but it may also expose them to higher risks from xenobiotics, because the organism may take up additional water during that time. This study aimed to assess the effects of molting on bioconcentration and survival after 96-h exposure to insecticide fipronil with or without oxygenase (CYP450s) inhibitor piperonyl butoxide (PBO) of two estuarine resident marine crustacean species: the sand shrimp Crangon uritai and the kuruma prawn Penaeus japonicus, with 96-h LC50 value of fipronil = 2.0 µg/L and 0.2 µg/L, respectively. Two graded concentrations included group high (H) (equivalent to the 96-h LC50 values) and low (L) (one-tenth of the H group concentration). Molting and survival were individually checked, and internal concentrations of fipronil and its metabolites (fipronil desulfinyl, fipronil sulfide, fipronil sulfone) were measured. The results showed that, only fipronil and fipronil sulfone were detected from organism, and that internal concentrations of these insecticides in molted specimens were higher than those of unmolted ones but comparable with those of dead ones. Accordingly, mortality was more frequent in molted specimens than those that were unmolted. Furthermore, involvement of oxygenase and higher lethal body burden threshold may confer higher tolerance to fipronil in sand shrimp than in the kuruma prawn. This study is the first to demonstrate that the body-residue-based approach is useful for deciphering the causal factors underlying fipronil toxicity, but highlights the need to consider physiological factors in arthropods, which influence and lie beyond body burden, molting and drug metabolism.


Assuntos
Inseticidas , Penaeidae , Poluentes Químicos da Água , Animais , Inseticidas/toxicidade , Muda , Oxigenases/farmacologia , Pirazóis , Poluentes Químicos da Água/toxicidade
10.
Ecotoxicology ; 31(5): 735-745, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35359216

RESUMO

Cadmium (Cd) is a non-essential element and can be toxic to aquatic organisms at low concentrations. Despite its well-known toxicity to Daphnia magna, the effects of Cd on physiological parameters (heart rate and thoracic limb activity) and molting- and reproduction-related genes are relatively understudied. In this study, D. magna were exposed to 0 (control), 25, 50 and 75 µg L-1 of Cd for 7 d and 21 d to determine the toxicity of Cd. The results showed that the Cd body burden in D. magna was significantly increased with elevated Cd concentrations, up to 13.4 µg Cd/g dry weight (dw) after exposure to 75 µg L-1 for 21 d. After 21 d of exposure, the body length and body weight of D. magna were significantly decreased in all Cd treatments compared to the control. The heart rate and thoracic limb activity were reduced by 4.3-11.7 and 5.0-10.3%, respectively. The levels of malondialdehyde (MDA) were increased by ~24-37% and the activity of catalase (CAT) was inhibited by ~50% compared to the control. The reproductive parameters (i.e., size of the first brood, the total number of offspring per female and the number of offspring per brood) were remarkably reduced, causing adverse effects on the population dynamics. In addition, the transcripts of genes (cyp314, cyp18a1, ecra, usp, hr3, cut, cht and cht3) related to the molting of D. magna were altered, whereas the transcripts of genes (vtg1, vtg2 and vmo1) related to reproduction were down-regulated. This study helps better understand the effects of Cd at different biological levels.


Assuntos
Traços de História de Vida , Poluentes Químicos da Água , Animais , Cádmio/toxicidade , Daphnia , Feminino , Muda , Reprodução , Poluentes Químicos da Água/toxicidade
11.
BMC Biol ; 20(1): 94, 2022 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-35477393

RESUMO

BACKGROUND: After embryonic development, Caenorhabditis elegans progress through for larval stages, each of them finishing with molting. The repetitive nature of C. elegans postembryonic development is considered an oscillatory process, a concept that has gained traction from regulation by a circadian clock gene homologue. Nevertheless, each larval stage has a defined duration and entails specific events. Since the overall duration of development is controlled by numerous factors, we have asked whether different rate-limiting interventions impact all stages equally. RESULTS: We have measured the duration of each stage of development for over 2500 larvae, under varied environmental conditions known to alter overall developmental rate. We applied changes in temperature and in the quantity and quality of nutrition and analysed the effect of genetically reduced insulin signalling. Our results show that the distinct developmental stages respond differently to these perturbations. The changes in the duration of specific larval stages seem to depend on stage-specific events. Furthermore, our high-resolution measurement of the effect of temperature on the stage-specific duration of development has unveiled novel features of temperature dependence in C. elegans postembryonic development. CONCLUSIONS: Altogether, our results show that multiple factors fine tune developmental timing, impacting larval stages independently. Further understanding of the regulation of this process will allow modelling the mechanisms that control developmental timing.


Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Regulação da Expressão Gênica no Desenvolvimento , Larva , Muda/fisiologia
12.
Arch Insect Biochem Physiol ; 110(3): e21894, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35362159

RESUMO

Much research has assumed that Notch codes one protein. Then the protein will be cleaved into two parts and regenerates a heterodimers receptor to construct Notch signal pathways to regulate development in the past three decades. Here, we show that Notch in brown planthopper is a complex alternatively spliced gene has at least three transcriptional start sites, four exon skips, and 21 transcriptional endpoints that uses these to form variants and codes a series of proteins. When used dsRNAs to suppression different regions of the full-length variant NlNF resulted in a similar phenotype. Insects were molting after treatment, sensation circles on antennas near to root decayed, bristles on wings shortened, thickened or disappeared, accompanied by thickening veins and blades of fore-wing apex regions thickened. These results suggested that Notch influenced developmental of sensation circles, bristles, veins, and blades in nymph late periods. This study has deepened our understanding of Notch.


Assuntos
Processamento Alternativo , Hemípteros , Animais , Éxons , Hemípteros/metabolismo , Muda , Ninfa/metabolismo
13.
Chemosphere ; 301: 134638, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35447218

RESUMO

The worldwide prawn industry strives for better production and environmental sustainability. Shrimp feed is one of the most expensive aquaculture inputs; therefore, it must be cost-effective and environmentally safe. Fish meals in aquaculture are becoming unsustainable due to the cost and environmental concerns. The effects of a biogas sludge meal supplement in feed on freshwater prawn productivity were studied. This study aimed to examine the growth, survival rate, yield, feed conversion ratio, and molting period of giant freshwater prawns (Macrobrachium rosenbergii) fed with and without biogas sludge a low-cost resource. The four treatments were T1 (0% biogas sludge), T2 (10% biogas sludge), T3 (20% biogas sludge), and T4 (30% biogas sludge). Protein content ranged from 26.7 to 27.4% in the experimental diets. The experiment was conducted in 3 × 3x1.5 m cages in an earthen pond for 80 days. The data shows that freshwater prawn growth performance did not differ significantly across treatments (P > 0.05). Biogas sludge has been demonstrated to be a low-cost feed component for freshwater prawns. Regarding survival, productivity, and feed conversion ratio, T2 (10% biogas sludge) outperformed the other two. As a result of the research, it was determined that 10% of biogas sludge might be used as a low-cost freshwater prawn feed option. The molting period of freshwater prawns fed biogas-containing feed was investigated at various levels. Freshwater prawns grown in baskets in a pond at 32.2 °C for a trial period of 90 days were molted differently (P > 0.05). The molting periods for Tl, T2, T3, and T4 were 19, 18, 19.8, and 20.8, respectively. In addition, the research suggests efficient and long-term methods for supplying nutrient-dense prawn feed to aquaculture production systems.


Assuntos
Muda , Palaemonidae , Animais , Biocombustíveis , Água Doce , Refeições , Esgotos
14.
Proc Biol Sci ; 289(1970): 20212404, 2022 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-35259984

RESUMO

Tropical bird species are characterized by a comparatively slow pace of life, being predictably different from their temperate zone counterparts in their investments in growth, survival and reproduction. In birds, the development of functional plumage is often considered energetically demanding investment, with consequences on individual fitness and survival. However, current knowledge of interspecific variation in feather growth patterns is mostly based on species of the northern temperate zone. We evaluated patterns in tail feather growth rates (FGR) and feather quality (stress-induced fault bar occurrence; FBO), using 1518 individuals of 167 species and 39 passerine families inhabiting Afrotropical and northern temperate zones. We detected a clear difference in feather traits between species breeding in the temperate and tropical zones, with the latter having significantly slower FGR and three times higher FBO. Moreover, trans-Saharan latitudinal migrants resembled temperate zone residents in that they exhibited a comparatively fast FGR and low FBO, despite sharing moulting environments with tropical species. Our results reveal convergent latitudinal shifts in feather growth investments (latitudinal syndrome) across unrelated passerine families and underscore the importance of breeding latitude in determining cross-species variation in key avian life-history traits.


Assuntos
Muda , Passeriformes , Animais , Cruzamento , Plumas , Humanos , Reprodução
15.
J Zoo Wildl Med ; 53(1): 173-186, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35339162

RESUMO

Although the evaluation of hematologic and biochemical parameters is a well-established diagnostic tool in vertebrate medicine, comprehensive understanding of these parameters in invertebrate species is lacking. This study provides baseline hemocyte concentrations and biochemistry values for a population of managed Japanese spider crabs (JSC; Macrocheira kaempferi) housed at six different public aquariums. The methodology for obtaining diagnostic hemolymph samples is described. Distinct hemocyte types were identified, including hyaline cells, semigranulocytes, and granulocytes, with hyaline cells as the predominant type. Correlates to exam findings and environmental parameters were evaluated and included higher absolute semigranulocyte counts (r = 0.65, P = 0.020) and triglyceride levels (r = 0.44, P = 0.014) in JSC with exoskeletal lesions; higher total protein (mean = 5.93 g/dl, P = 0.028), cholesterol (median = 18.5 mg/dl, P = 0.018), triglyceride (median = 15.5 mg/dl, P = 0.002), and amylase (median = 243 U/L, P = 0.013) in nonmolting JSC compared with JSC that have previously molted since acquisition (total protein mean = 4.83 g/dl, cholesterol median = 14 mg/dl, triglyceride median = 6.4 mg/dl, and amylase median = 131 U/L); and lower relative and absolute granulocyte counts (mean = 8.83% P = 0.030, median = 1,162 cells/µl P = 0.006, respectively) and higher albumin (median = 1.35 g/dl, P = 0.031) in JSC housed at facilities that used ozone sterilization. The data presented serve as a foundation for understanding basic clinical parameters in JSC hemolymph, as well as the potential influence of environmental stressors on those parameters.


Assuntos
Hemócitos , Hemolinfa , Animais , Japão , Contagem de Leucócitos/veterinária , Muda
16.
Dev Biol ; 485: 70-79, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35248548

RESUMO

Caste development in social insects requires the coordination of molting and metamorphosis during postembryonic development. In termites, i.e., hemimetabolous eusocial insects, caste fate is determined during postembryonic development. However, it is not fully understood how the mechanisms of molting/metamorphosis are regulated in the course of differentiation between reproductive and sterile castes. In termites, only reproductives derived from alates are imagos and other sterile castes (including developmentally-terminal soldier caste) are basically juveniles or nymphs. Furthermore, supplementary reproductives that appear when the original queens and kings die or become senescent, exhibit larval features such as winglessness, and are called neotenics. Therefore, the question of whether neotenics are larvae or imagos is still under debate. In this study, by inducing female neotenic differentiation in a damp-wood termite Hodotermopsis sjostedti, morphological investigations together with juvenile hormone (JH) quantification and expression/functional analyses of genes responsible for molting and/or metamorphosis were carried out. JH titer and expression of one of the downstream genes (Kr-h1) were shown to be temporarily lowered, but increased just prior to the molt into neotenics, while consistently lowered in imaginal molt (i.e., alate differentiation). In contrast, ecdysone-related genes (EcR and E93) were upregulated at both neotenic and alate differentiation, suggesting that the heterochronic actions of ecdysone and JH lead the neotenic differentiation. Moreover, expression analyses, supported by reverse genetic experiments, showed that EcR and E93 were specifically upregulated in genital sternites (EcR and E93) and ovaries (E93) and required for the development of imaginal characters. These results suggest that the resultant mosaic phenotype of female neotenics is due to modular responses of different body parts to hormonal actions.


Assuntos
Isópteros , Animais , Ecdisona/metabolismo , Feminino , Isópteros/genética , Isópteros/metabolismo , Hormônios Juvenis/metabolismo , Muda/genética , Diferenciação Sexual
17.
Pestic Biochem Physiol ; 182: 105029, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35249644

RESUMO

Fushi-tarazu factor 1 (FTZF1) is an ecdysone-inducible transcription factor that plays a vital role during the metamorphosis in insects. In this study, we functionally characterized HvFTZ-F1 in H. vigintioctopunctata, a dreadful solanaceous crop pest, by using a dietary RNA interference technique. The HvFTZ-F1 expression levels were elevated in the 1st and 2nd-instars before molting and declined immediately after ecdysis. The HvFTZ-F1 silencing led to high mortality in the 1st instars, while the expression of the osmosis-regulative gene, HvAQPAn.G, was significantly increased in the 1st instars. HvFTZ-F1 silencing downregulated the Halloween and 20E-related genes, decreased the ecdysteroids titer, suppressed the expression of pigmentation-related genes, and reduced the catecholamines titer. In the 4th instars, HvFTZ-F1 silencing caused 100% mortality by arresting the development at the prepupal stage and preventing new abdominal cuticle formation. In the female adults, HvFTZ-F1 silencing caused an evident decrease in fecundity, prolonged the pre-oviposition period, reduced the number of eggs and hatching rate, severely atrophied the ovaries. Moreover, the 20E-related genes and the dopamine synthesis genes were suppressed in the dsHvFTZ-F1-treated females. Overall, our results revealed that HvFTZ-F1 regulates ecdysis, pupation, and reproduction in H. vigintioctopunctata, thereby could be a promising molecular target for the development of RNAi-based biopesticides to control H. vigintioctopunctata.


Assuntos
Muda , Solanum tuberosum , Animais , Medicamentos de Ervas Chinesas , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Larva/genética , Muda/genética , Interferência de RNA , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Reprodução , Solanum tuberosum/metabolismo
18.
Fish Shellfish Immunol ; 122: 268-275, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35134516

RESUMO

In the pond culture of Chinese mitten crabs, limb autotomy seriously affects the feeding efficiency, immunity and survival. Therefore, it is crucial to understand the mechanism of limb regeneration of mitten crabs, so that culture strategies could be developed to reduce the limb impairment rate. The insulin-like signaling (ILS) pathway is evolutionarily conserved, and plays key roles in the growth and immunity of various species. In this study, a full-length cDNA of insulin-like receptor (EsInR) was identified from Eriocheir sinensis, and its mRNA expression patterns during limb regeneration was evaluated. The cDNA of EsInR includes a 4326 bp ORF encoding a protein of 1441 amino acids, with conserved α-and ß-subunits. The EsInR and genes related to ILS were found to be upregulated during limb regeneration, which indicated that ILS plays a key role in limb regeneration of E. sinensis. Our experiment revealed that inhibition of ILS through injection of the InR inhibitor GSK1838705A at the blastema formation stage significantly reduced the limb regeneration rate compared to control group. In addition, injection of GSK1838705A also reduced the size of newly formed limbs after the molting cycle. Furthermore, we found that genes related to myogenesis were downregulated following injection of InR inhibitor both before and after molting. The results also indicated that cyclins and CDK1 were downregulated, while CKIs were upregulated following treatment with the InR inhibitor. These results suggest that ILS regulates limb regeneration in E. sinensis by promoting muscle growth and regeneration in response to autotomy stress. Thus, we identified a conserved insulin-like receptor in E. sinensis, and provide new evidence for the involvement of ILS in the regulation of limb autotomy and regeneration in crustaceans.


Assuntos
Braquiúros , Insulina , Animais , Braquiúros/genética , China , DNA Complementar , Insulina/genética , Muda/genética , Filogenia , Regeneração
19.
Fish Shellfish Immunol ; 122: 419-425, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35182722

RESUMO

The widespread occurrence and accumulation of plastic waste have been globally recognized as a critical issue. However, few researches have evaluated the adverse effects of nanoplastics to freshwater organisms. Thus, here, the effects of polystyrene nanoplastics (PS-NP) on the physiological changes (i.e., molting) and enzyme activity of oxidative stress were investigated in the adult freshwater prawn Macrobrachium nipponense. Based on a previous study and environmental microplastic concentrations, the prawn was exposed to 0, 0.04, 0.4, 4, and 40 mg/L waterborne PS-NP for 21 days. The results showed that growth and survival-related parameters were not affected by all PS-NP groups, while the molting rate were significantly decreased in the 4 and 40 mg/L PS-NP group. Meanwhile, the expression of molting-related gene (calcium-calmodulin-dependent protein kinase I, ecdysteroid receptor, and leucine-rich repeat-containing G-protein-coupled receptor 2) were significantly decreased. H2O2 content was significantly increased in all PS-NP groups relative to the control. Lower concentrations of PS-NP increased the activity of superoxide dismutase (SOD), glutathione S-transferase (GST), and glutathione peroxidase (GSH-Px), whereas increased concentrations, decreased SOD, GST, and GSH-Px activity. These results suggest that chronic exposure to PS-NP at an environmental concentration impaired molting and induced oxidative stress in the adult river prawn Macrobrachium nipponense. The findings provided basic information for assessing the risk assessment of nanoplastics and revealing the molecular mechanisms of nanoplastics toxicity.


Assuntos
Palaemonidae , Poluentes Químicos da Água , Animais , Peróxido de Hidrogênio/farmacologia , Microplásticos/toxicidade , Muda/genética , Estresse Oxidativo , Palaemonidae/genética , Plásticos , Poliestirenos/toxicidade , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/toxicidade
20.
J Therm Biol ; 104: 103183, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35180962

RESUMO

The moult in southern elephant seals (Mirounga leonina) represents an especially energetically demanding period during which seals must maintain high skin temperature to facilitate complete replacement of body fur and upper dermis. In this study, heat flux from the body surface was measured on 18 moulting southern elephant seals to estimate metabolic heat loss in three different habitats (beach, wallow and vegetation). Temperature data loggers were also deployed on 10 southern elephant seals to monitor skin surface temperature. On average, heat loss of animals on the beach was greater than in wallows or vegetation, and greater in wallows than in vegetation. Heat loss across all habitats during the moult equated to 1.8 x resting metabolic rate (RMR). The greatest heat loss of animals was recorded in the beach habitat during the late moult, that represented 2.3 x RMR. Mass loss was 3.6 ± 0.3 kg day-1, resulting in changes in body condition as the moult progressed. As body condition declined, skin surface temperature also decreased, suggesting that as animals approached the end of the moult blood flow to the skin surface was no longer required for hair growth.


Assuntos
Regulação da Temperatura Corporal , Ecossistema , Muda/fisiologia , Focas Verdadeiras/fisiologia , Animais , Feminino , Masculino , Temperatura
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