scholarly journals TmDorX2 positively regulates antimicrobial peptides in Tenebrio molitor gut, fat body, and hemocytes in response to bacterial and fungal infection

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Maryam Keshavarz ◽  
Yong Hun Jo ◽  
Ki Beom Park ◽  
Hye Jin Ko ◽  
Tariku Tesfaye Edosa ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Antimicrobial Peptides ◽  
Post Infection ◽  
Fat Body ◽  
Tenebrio Molitor ◽  
Malpighian Tubules ◽  
Whole Body ◽  
Mrna Levels ◽  
E Coli ◽  
Pathogen Invasion

AbstractDorsal, a member of the nuclear factor-kappa B (NF-κB) family of transcription factors, is a critical downstream component of the Toll pathway that regulates the expression of antimicrobial peptides (AMPs) against pathogen invasion. In this study, the full-length ORF of Dorsal was identified from the RNA-seq database of the mealworm beetle Tenebrio molitor (TmDorX2). The ORF of TmDorX2 was 1,482 bp in length, encoding a polypeptide of 493 amino acid residues. TmDorX2 contains a conserved Rel homology domain (RHD) and an immunoglobulin-like, plexins, and transcription factors (IPT) domain. TmDorX2 mRNA was detected in all developmental stages, with the highest levels observed in 3-day-old adults. TmDorX2 transcripts were highly expressed in the adult Malpighian tubules (MT) and the larval fat body and MT tissues. After challenging the larvae with Staphylococcus aureus and Escherichia coli, the TmDorX2 mRNA levels were upregulated 6 and 9 h post infection in the whole body, fat body, and hemocytes. Upon Candida albicans challenge, the TmDorX2 mRNA expression were found highest at 9 h post-infection in the fat body. In addition, TmDorX2-knockdown larvae exposed to E. coli, S. aureus, or C. albicans challenge showed a significantly increased mortality rate. Furthermore, the expression of 11 AMP genes was downregulated in the gut and fat body of dsTmDorX2-injected larvae upon E. coli challenge. After C. albicans and S. aureus challenge of dsTmDorX2-injected larvae, the expression of 11 and 10 AMPs was downregulated in the gut and fat body, respectively. Intriguingly, the expression of antifungal transcripts TmTenecin-3 and TmThaumatin-like protein-1 and -2 was greatly decreased in TmDorX2-silenced larvae in response to C. albicans challenge, suggesting that TmDorX2 regulates antifungal AMPs in the gut in response to C. albicans infection. The AMP expression profiles in the fat body, hemocytes, gut, and MTs suggest that TmDorX2 might have an important role in promoting the survival of T. molitor larvae against all mentioned pathogens.

scholarly journals TmIKKε Is Required to Confer Protection Against Gram-Negative Bacteria, E. coli by the Regulation of Antimicrobial Peptide Production in the Tenebrio molitor Fat Body

2022 ◽  
Vol 12 ◽  
Author(s):  
Hye Jin Ko ◽  
Bharat Bhusan Patnaik ◽  
Ki Beom Park ◽  
Chang Eun Kim ◽  
Snigdha Baliarsingh ◽  
...  
Keyword(s):  
Messenger Rna ◽  
Catalytic Domain ◽  
Fat Body ◽  
Tenebrio Molitor ◽  
Instar Larva ◽  
Malpighian Tubules ◽  
Amino Acid Residues ◽  
Innate Immune Responses ◽  
Reading Frame ◽  
E Coli

The inhibitor of nuclear factor-kappa B (NF-κB) kinase (IKK) is the core regulator of the NF-κB pathway against pathogenic invasion in vertebrates or invertebrates. IKKβ, -ε and -γ have pivotal roles in the Toll and immune deficiency (IMD) pathways. In this study, a homolog of IKKε (TmIKKε) was identified from Tenebrio molitor RNA sequence database and functionally characterized for its role in regulating immune signaling pathways in insects. The TmIKKε gene is characterized by two exons and one intron comprising an open reading frame (ORF) of 2,196 bp that putatively encodes a polypeptide of 731 amino acid residues. TmIKKε contains a serine/threonine protein kinases catalytic domain. Phylogenetic analysis established the close homology of TmIKKε to Tribolium castaneum IKKε (TcIKKε) and its proximity with other IKK-related kinases. The expression of TmIKKε mRNA was elevated in the gut, integument, and hemocytes of the last-instar larva and the fat body, Malpighian tubules, and testis of 5-day-old adults. TmIKKε expression was significantly induced by Escherichia coli, Staphylococcus aureus, and Candida albicans challenge in whole larvae and tissues, such as hemocytes, gut, and fat body. The knockdown of the TmIKKε messenger RNA (mRNA) expression significantly reduced the survival of the larvae against microbial challenges. Further, we investigated the induction patterns of 14 T. molitor antimicrobial peptides (AMPs) genes in TmIKKε gene-silencing model after microbial challenges. While in hemocytes, the transcriptional regulation of most AMPs was negatively regulated in the gut and fat body tissue of T. molitor, AMPs, such as TmTenecin 1, TmTenecin 4, TmDefensin, TmColeoptericin A, TmColeoptericin B, TmAttacin 1a, and TmAttacin 2, were positively regulated in TmIKKε-silenced individuals after microbial challenge. Collectively, the results implicate TmIKKε as an important factor in antimicrobial innate immune responses in T. molitor.

scholarly journals Critical Roles of Spätzle5 in Antimicrobial Peptide Production Against Escherichia coli in Tenebrio molitor Malpighian Tubules

2021 ◽  
Vol 12 ◽  
Author(s):  
Maryam Ali Mohammadie Kojour ◽  
Tariku Tesfaye Edosa ◽  
Ho Am Jang ◽  
Maryam Keshavarz ◽  
Yong Hun Jo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Peptide ◽  
Bacterial Infections ◽  
Tenebrio Molitor ◽  
Larval Survival ◽  
Malpighian Tubules ◽  
Control Group ◽  
Mrna Levels ◽  
E Coli ◽  
Pathway Activation

The dimeric cytokine ligand Spätzle (Spz) is responsible for Toll pathway activation and antimicrobial peptide (AMP) production upon pathogen challenge in Tenebrio molitor. Here, we indicated that TmSpz5 has a functional role in response to bacterial infections. We showed that the highest expression of TmSpz5 is induced by Candida albicans. However, TmSpz5 knockdown reduced larval survival against Escherichia coli and Staphylococcus aureus. To evaluate the molecular mechanism underlying the observed survival differences, the role of TmSpz5 in AMP production was examined by RNA interference and microbial injection. T. molitor AMPs that are active against Gram-negative and -positive bacteria, including Tmtenecins, Tmattacins, Tmcoleoptericins, Tmtaumatin-like-proteins, and Tmcecropin-2, were significantly downregulated by TmSpz-5 RNAi in the Malpighian tubules (MTs) following a challenge with E. coli and S. aureus. However, upon infection with C. albicans the mRNA levels of most AMPs in the dsTmSpz5-injected group were similar to those in the control groups. Likewise, the expression of the transcription factors NF-κB, TmDorX2, and TmRelish were noticeably suppressed in the MTs of TmSpz5-silenced larvae. Moreover, E. coli-infected TmSpz5 knockdown larvae showed decreased antimicrobial activity in the MTs and hindgut compared with the control group. These results demonstrate that TmSpz5 has a defined role in T. molitor innate immunity by regulating AMP expression in MTs in response to E. coli.

Hymenolepis diminuta: metacestode-induced reduction in the synthesis of the yolk protein, vitellogenin, in the fat body of Tenebrio molitor

Parasitology ◽  
1996 ◽  
Vol 112 (4) ◽  
pp. 429-436 ◽  
Author(s):  
T. J. Webb ◽  
H. Hurd
Keyword(s):  
Post Infection ◽  
Fat Body ◽  
Potent Inhibitor ◽  
Tenebrio Molitor ◽  
Hymenolepis Diminuta ◽  
Vitellogenin Synthesis ◽  
Specific Stage ◽  
Fat Bodies ◽  
Do So

SUMMARYVitellogenin synthesis by the fat body has been monitored using in vitro culture and immunoprecipitation. This system was found to be efficient for measuring vitellogenin production in both non-infected Tenebrio molitor and those infected with Hymenolepis diminuta. In fat bodies from infected beetles, vitellogenin production was decreased by up to 75% (day 24 post-infection) and, at all times investigated, vitellogenin synthesis was significantly below control levels (days 3–30 post-infection). Incubating fat bodies from control insects with isolated metacestodes indicated that this may be a direct effect by the parasite which is developmental stage-specific. Stage II, but not stage III–IV, nor heat-killed parasites could bring about this decrease in vitellogenin. In addition, these effects may be density dependent within the range of 2–20 parasites per fat body; only 2 metacestodes were necessary to cause a significant decrease. Since metacestodes do not take up vitellogenin, nor limit the amount of [14C] leucine available to the fat body for vitellogenin production, it is conceivable that the parasite produces a potent inhibitor of vitellogenin synthesis, or a molecule which induces cells within the fat body to do so.

scholarly journals TmPGRP-SA regulates Antimicrobial Response to Bacteria and Fungi in the Fat Body and Gut of Tenebrio molitor

2020 ◽  
Vol 21 (6) ◽  
pp. 2113 ◽  
Author(s):  
Maryam Keshavarz ◽  
Yong Hun Jo ◽  
Tariku Tesfaye Edosa ◽  
Young Min Bae ◽  
Yeon Soo Han
Keyword(s):  
Escherichia Coli ◽  
Fat Body ◽  
Mrna Level ◽  
Tenebrio Molitor ◽  
Mortality Rates ◽  
E Coli ◽  
Peptidoglycan Recognition Protein ◽  
Recognition Protein ◽  
Bacteria And Fungi ◽  
Antimicrobial Immune Response

Antimicrobial immune response is mediated by a signal-transducing sensor, peptidoglycan recognition protein-SA (PGRP-SA), that can recognize non-self molecules. Although several studies have focused on the involvement of Drosophila PGRP-SA in antimicrobial peptide (AMP) expression in response to infections, studies on its role in Tenebrio molitor are lacking. Here, we present a functional analysis of T. molitor PGRP-SA (TmPGRP-SA). In the absence of microbes, TmPGRP-SA was highly expressed in the late-larval fat body, followed by hemocytes, and gut. Interestingly, following Escherichia coli, Staphylococcus aureus, and Candida albicans infections, the mRNA level of TmPGRP-SA was significantly upregulated in both the fat body and gut. TmPGRP-SA silencing had a significant effect on the mortality rates for all the microbes tested. Moreover, TmPGRP-SA is required for regulating the expression of eight AMP genes namely TmTenecin-1, -2, and -4; TmDefensin-1 and -2; TmColeoptericin-1; and TmAttacin-1b and -2 in the fat body in response to E. coli and S. aureus infections. TmPGRP-SA is essential for the transcription of TmTenecin-2, -4; TmDefensin-2; TmColeoptericin-1, -2; and TmAttacin-1a, -1b, and -2 in the gut upon E. coli and C. albicans infections. However, TmPGRP-SA does not regulate AMP expression in the hemocytes. Additionally, TmDorsal isoform X2, a downstream Toll transcription factor, was downregulated in TmPGRP-SA-silenced larval fat body following E. coli and S. aureus challenges, and in the gut following E. coli and C. albicans challenges.

Hymenolepis diminuta: influence of metacestodes on synthesis and secretion of fat body protein and its ovarian sequestration in the intermediate host, Tenebrio molitor

Parasitology ◽  
1986 ◽  
Vol 93 (1) ◽  
pp. 111-120 ◽  
Author(s):  
Hilary Hurd ◽  
C. Arme
Keyword(s):  
Intermediate Host ◽  
Post Infection ◽  
Fat Body ◽  
Tenebrio Molitor ◽  
Hymenolepis Diminuta ◽  
Body Protein ◽  
Concomitant Reduction ◽  
Fat Bodies

SUMMARYFemale Tenebrio molitor infected with metacestodes of Hymenolepis diminuta exhibit elevated concentrations of female-specific proteins in their haemolymph and the origin of these has been investigated. Following a 4 h in vitro incubation with [14C]leucine, fat bodies from non-infected females secreted 13 times more protein than those from females 12 days post-infection. A comparison of the uptake in vivo of radio-isotope labelled amino acids by ovaries from non-infected and infected beetles of various ages revealed no differences; however, a 51·5% decrease in protein sequestration was detected in females 12 days post-infection. Electrophoresis of homogenates of radio-isotope labelled ovaries demonstrated that the majority of label was associated with vitellin sub-units. It is suggested that the decrease in vitellogenin sequestration associated with infection results in an increase in the haemolymph concentration of these proteins despite a concomitant reduction in their secretion by fat bodies. Both fat body synthesis and ovarian sequestration are under juvenile hormone control and it is proposed that metacestodes of H. diminuta may cause a reduction in the concentration of this hormone in the intermediate host.

scholarly journals Two Roles for the Tenebrio molitor Relish in the Regulation of Antimicrobial Peptides and Autophagy-Related Genes in Response to Listeria monocytogenes

Insects ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 188 ◽  
Author(s):  
Maryam Keshavarz ◽  
Yong Hun Jo ◽  
Tariku Tesfaye Edosa ◽  
Yeon Soo Han
Keyword(s):  
Listeria Monocytogenes ◽  
Antimicrobial Peptides ◽  
Fat Body ◽  
Early Stage ◽  
Tenebrio Molitor ◽  
Imd Pathway ◽  
Atg Genes ◽  
Notable Increase ◽  
Significant Mortality

Relish is a key NF-κB transcription factor of the immune-deficiency (Imd) pathway that combats infection by regulating antimicrobial peptides (AMPs). Understanding of the fundamental role of Tenebrio molitor Relish (TmRelish) in controlling of Listeria monocytogenes virulence through the regulation of both AMPs and autophagy-related (ATG) genes is unclear. Here, we show that TmRelish transcripts were highly abundant in the larval fat body and hemocytes compared to the gut upon L. monocytogenes infection. Furthermore, significant mortality was observed in TmRelish-silenced larvae after intracellular insult. To investigate the cause of this lethality, we measured the induction of AMPs and ATG genes in the TmRelish dsRNA-treated T. molitor larvae. The expression of TmTenecin-1, TmTenecin-4, TmColeptericin-1, TmAttacin-2, and TmCecropin-2 were suppressed in the fat body and hemocytes of dsTmRelish-injected larvae during L. monocytogenes infection. In addition, TmRelish knockdown led to a noticeable downregulation of TmATG1 (a serine-threonine protein kinase) in the fat body and hemocytes of young larvae 6 h post-infection (pi). The notable increase of autophagy genes in the early stage of infection (6 h pi), suggesting autophagy response is crucial for Listeria clearance. Taken together, these results suggest that TmRelish plays pivotal roles in not only regulation of AMP genes but also induction of autophagy genes in response to L. monocytogenes challenge in fat body and hemocytes of T. molitor larvae. Furthermore, negative regulation of several AMPs by TmRelish in the fat body, hemocytes, and gut leaves open the possibility of a crosstalk between Toll and Imd pathway.

Effect of metacestodes of Hymenolepis diminuta on storage and circulating carbohydrates in the intermediate host, Tenebrio molitor

Parasitology ◽  
1994 ◽  
Vol 108 (4) ◽  
pp. 473-478 ◽  
Author(s):  
J. Y. Kearns ◽  
H. Hurd ◽  
A. S. Pullin
Keyword(s):  
Gas Chromatography ◽  
Resource Management ◽  
Intermediate Host ◽  
Post Infection ◽  
Fat Body ◽  
Tenebrio Molitor ◽  
Reproductive Physiology ◽  
Hymenolepis Diminuta ◽  
Carbohydrate Reserves ◽  
Biochemical Studies

SUMMARYThe metamorphosis of oncospheres of the rat tapeworm, Hymenolepis diminuta, to mature metacestodes induces several pathophysiological effects in the intermediate host, Tenebrio molitor (Coleoptera). Previous investigations have failed to elucidate the mechanism responsible for changes in the host reproductive physiology and behaviour. This work forms part of an assessment of the degree to which nutrient resource management may be involved in these interactions. We report that developing metacestodes exert a pronounced effect upon host carbohydrate reserves and also alter circulating carbohydrate titres at some stages post-infection. Biochemical studies of fat body glycogen demonstrated a significant depletion of reserves as early as 3 days post-infection in males and 5 days post-infection in females. Gas chromatography revealed trehalose to be the predominant haemolymph carbohydrate, titres being significantly elevated in male beetles 5 and 9 days post-infection and in females 12 days post-infection. Metacestodes had no effect on glucose concentrations in male or female beetles.

scholarly journals Transcriptional Regulation of β-Defensin Gene Expression in Tracheal Epithelial Cells

2000 ◽  
Vol 68 (1) ◽  
pp. 113-119 ◽  
Author(s):  
Gill Diamond ◽  
Vicki Kaiser ◽  
Janice Rhodes ◽  
John P. Russell ◽  
Charles L. Bevins
Keyword(s):  
Innate Immunity ◽  
Transcription Factors ◽  
Epithelial Cells ◽  
Antimicrobial Peptides ◽  
Binding Sites ◽  
Binding Activity ◽  
Mrna Levels ◽  
Tracheal Epithelial Cells ◽  
Tracheal Epithelial ◽  
Flanking Region

ABSTRACT Innate immunity provides an ever-present or rapidly inducible initial defense against microbial infection. Among the effector molecules of this defense in many species are broad-spectrum antimicrobial peptides. Tracheal antimicrobial peptide (TAP) was the first discovered member of the β-defensin family of mammalian antimicrobial peptides. TAP is expressed in the ciliated epithelium of the bovine trachea, and its mRNA levels are dramatically increased upon stimulation with bacteria or bacterial lipopolysaccharide (LPS). We report here that this induction by LPS is regulated at the level of transcription. Furthermore, the transfection of reporter gene constructs into tracheal epithelial cells indicates that DNA sequences in the 5′ flanking region of the TAP gene, within 324 nucleotides of the transcription start site, are responsible in part for mediating gene induction. This region includes consensus binding sites for NF-κB and nuclear factor interleukin-6 (NF IL-6) transcription factors. Gel mobility shift assays indicate that LPS induces NF-κB binding activity in the nuclei of these cells, while NF IL-6 binding activity is constitutively present. The gene encoding human β-defensin 2, a human homologue of TAP with similar inducible expression patterns in the airway, was cloned and found to have conserved NF-κB and NF IL-6 consensus binding sites in its 5′ flanking region. Previous studies of antimicrobial peptides from insects indicated that their induction by infectious microbes and microbial products also occurs via activation of NF-κB-like and NF IL-6-like transcription factors. Together, these observations indicate that a strategy for the induction of peptide-based antimicrobial innate immunity is conserved among evolutionarily diverse organisms.

Fat body cells and calcium phosphate spherules induce ice nucleation in the freeze-tolerant larvae of the gall fly Eurosta solidaginis (Diptera, Tephritidae)

1996 ◽  
Vol 199 (2) ◽  
pp. 465-471 ◽  
Author(s):  
J Mugnano ◽  
R Lee ◽  
R Taylor
Keyword(s):  
Calcium Phosphate ◽  
Fat Body ◽  
Freeze Tolerance ◽  
Ice Nucleation ◽  
Malpighian Tubules ◽  
Whole Body ◽  
Eurosta Solidaginis ◽  
New Class ◽  
Ice Nucleators ◽  
Freeze Tolerant

During the autumn, the third-instar larvae of the gall fly Eurosta solidaginis acquire freeze tolerance and their crystallization temperatures increase into the -8 to -10 °C range. Despite conflicting reports, efficient endogenous ice nucleators have not been identified in this freeze-tolerant insect. We found large crystalloid spheres within the Malpighian tubules of overwintering larvae. Energy-dispersive X-ray microanalysis and infrared spectroscopy indicated that the spherules were a hydrate of tribasic calcium phosphate. To test for ice-nucleating activity, we placed the calcium phosphate spherules in 10 µl of Schneider's insect medium and cooled them in a refrigerated bath. The addition of spherules increased the crystallization temperature of Schneider's medium by approximately 8 C, from -18.4±0.8 °C to -10.1±0.9 °C (mean ± s.e.m., N=20). Ice-nucleating activity (-10.9±0.9 °C) was also demonstrated in fat body cells suspended in 10 µl of Schneider's medium. Both calcium phosphate spherules and fat body cells have ice-nucleating activity sufficiently high to explain whole-body crystallization temperatures. Furthermore, other crystalloid deposits, commonly found in diapausing or overwintering insects, also exhibited significant ice-nucleating activity. These endogenous crystalloid deposits represent a new class of heterogeneous ice nucleators that potentially regulate supercooling and promote freeze tolerance in E. solidaginis and possibly in other overwintering insects.

scholarly journals Tenebrio molitor Spätzle 1b Is Required to Confer Antibacterial Defense Against Gram-Negative Bacteria by Regulation of Antimicrobial Peptides

2021 ◽  
Vol 12 ◽  
Author(s):  
Young Min Bae ◽  
Yong Hun Jo ◽  
Bharat Bhusan Patnaik ◽  
Bo Bae Kim ◽  
Ki Beom Park ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Antimicrobial Peptides ◽  
Signaling Pathway ◽  
Tenebrio Molitor ◽  
Functional Assay ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Reading Frame ◽  
E Coli ◽  
Toll Signaling

Innate immunity is the ultimate line of defense against invading pathogens in insects. Unlike in the mammalian model, in the insect model, invading pathogens are recognized by extracellular receptors, which activate the Toll signaling pathway through an extracellular serine protease cascade. In the Toll-NF-κB pathway, the extracellular spätzle protein acts as a downstream ligand for Toll receptors in insects. In this study, we identified a novel Spätzle isoform (TmSpz1b) from RNA sequencing database of Tenebrio molitor. TmSpz1b was bioinformatically analyzed, and functionally characterized for the antimicrobial function by RNA interference (RNAi). The 702 bp open reading frame of TmSpz1b encoded a putative protein of 233 amino acid residues. A conserved cystine-knot domain with seven cysteine residues in TmSpz1b was involved in three disulfide bridges and the formation of a spätzle dimer. TmSpz1b was mostly expressed in the hemocytes of T. molitor late instar larvae. The mRNA expression of TmSpz1b was highly induced in the hemocytes after Escherichia coli, Staphylococcus aureus, and Candida albicans stimulation of T. molitor larvae. TmSpz1b silenced larvae were significantly more susceptible to E. coli infection. In addition, RNAi-based functional assay characterized TmSpz1b to be involved in the positive regulation of antimicrobial peptide genes in hemocytes and fat bodies. Further, the TmDorX2 transcripts were downregulated in TmSpz1b silenced individuals upon E. coli challenge suggesting the relationship to Toll signaling pathway. These results indicate that TmSpz1b is involved in the T. molitor innate immunity, causes the sequestration of Gram-negative bacteria by the regulatory action of antimicrobial peptides, and enhances the survival of T. molitor larvae.

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