• Journal of fish pathology
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• v.24 no.3
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• pp.279-287
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• 2011

Transcriptional response patterns of mud loach (Misgurnus mizolepis; Cypriniformes) hepcidin, a potential ortholog to human hamp1, in response to experimental challenges with non-pathogenic and pathogenic bacterial species were analyzed based on the semi-quantitative reverse transcription-PCR assay. Mud loach hepcidin transcripts were much more preferentially induced by pathogenic bacterial species (Edwardsiella tarda and Vibrio anguillarum) causing apparent pathological symptoms than by non-pathogenic species (Escherichia coli and Bacillus thuringiensis) displaying neither clinical signs nor mortality. However in overall, the induced amounts of hepcidin transcripts were positively related with the number of bacterial cells delivered in both pathogenic and non-pathogenic bacterial species. Inducibility of hepcidin transcripts were variable among three tissues examined (liver, kidney and spleen) in which kidney and spleen were more responsive to the bacterial challenge than liver. Time course expression patterns of hepcidin mRNAs after challenge were different between groups challenged with pathogenic and non-pathogenic species, although the overall pattern of hepcidin expression was in accordance with that generally observed in battery genes appeared during early phase of inflammation. Fish challenged with E. coli (non-pathogenic) showed the significant induction of hepcidin transcripts within 24 hr post injection (hpi) but the level was rapidly declined to the basal level either at 48 or 96 hpi. On the other hand, hepcidin transcript levels in E. tarda (pathogenic)-challenged fish were continuously elevated until 48 hpi, then downregulated at 96 hpi, although the level at 96 hpi was still significantly higher than control level observed in non-challenged fish. This expression pattern was consistent in all the three tissues examined. Taken together, our data indicate that hepcidin is tightly in relation with pathological and/or inflammation status during bacterial challenge, consequently providing useful basis to extend knowledge on the host defensive roles of hepcidin under infectious conditions in bony fish.

• Journal of fish pathology
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• v.5 no.2
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• pp.61-75
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• 1992

Experimental infection method for Edwardsiellosis was studied to imitate histopathologically natural infections in the Tilapia Oreochrimis niloticus. Prior to the bacterial challenge, the intestine of tilapia was damaged by 0.2ml of 30% hydrogen peroxide introduced through a silicon tube which was inserted 4 to 5cm into the intestine from anus. E. tarda was mixed a 10% Gum arabia and administered into the stomach by a cannula 20 hours after the hydrogen peroxide treatment. Bacterial doses used were from $4.2{\times}10^6$ to $6.4{\times}10^\;CFU$/fish. Fish 72 hours after the challenged showed swollen and erosious lesion and focal necrosis with bacterial-eaden inflammatory cell in the Liver, Spleen, Kidney. Fish 96 and 120 hours after bacterial challenge were moribund showing swollen Liver, Spleen, Kidney and focal accumulation of macrophages and production of granulomas in the infected lesions.

• Journal of fish pathology
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• v.24 no.3
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• pp.269-278
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• 2011

Gene expression of two glyceraldehyde-3-phosphate dehydrogenase (GAPDH) paralogs was examined during Edwardsiella tarda challenge and heavy metal exposures in mud loach (Misgurnus mizolepis; Cypriniformes) kidney and spleen. Transcription of the two mud loach GAPDH paralogs (mlGAPDH-1 and mlGAPDH-2) was significantly modulated by these stimulatory challenges in an isoform-dependent manner. Based on the real-time RT-PCR analysis, the mlGAPDH-2 transcripts were more preferentially induced by E. tarda challenge, whereas the mlGAPDH-1 transcripts were proven to show more inducibility in response to heavy metal exposure using Cd, Cu, Mn and Zn at $5{\mu}M$. Their isoform-specific response patterns were closely in accordance with the TF binding profiles in promoter and intron-1 of the two mlGAPDH isoforms, in which the mlGAPDH-2 has more binding sites for immune-related transcription factors than mlGAPDH-1 while the mlGAPDH-1 possesses exclusively metal responsive elements in its intron. Collectively, the mlGAPDHs are potentially involved in cellular pathways independent of glycolysis and the two GAPDH paralogs might undergo functional diversification or subfunctionalization at least at the transcription level.

• The Plant Pathology Journal
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• v.23 no.3
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• pp.203-209
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• 2007

Infection structures were observed using a fluorescence microscope at the penetration sites on the leaves of potato plants pre-inoculated with the bacterial strains Pseudomonas putida TRL2-3, Micrococcus luteus TRK2-2, and Flexibacteraceae bacterium MRL412, which mediated an induced systemic resistance on potato plants against late blight disease caused by Phytophthora infestans. In order to compare the infection structures on the leaves expressing systemic acquired resistance, the leaves of potato plants pre-treated with DL-3-amino butyric acid (BABA) were also observed after challenge inoculation with the same pathogen. The infection structures were investigated. The total number of germination and appressorium formation of P. infestans were counted. Furthermore, the frequencies of fluorescent epidermal cells at the penetration sites, which indicate a defense response of plant cell, were estimated. There were no differences on the germination rates of the fungal cysts among the untreated control, BABA pre-treated, and bacterial strains pre-inoculated plants. However, appressorium formation was slightly decreased on the leaves of BABA pre-treated plants compared to those of untreated as well as bacterial strains pre-inoculated plants. Furthermore, the frequencies of fluorescent cells of BABA pre-treated and bacterial strains pre-inoculated were higher than that of untreated plants, indicating an active defense reaction of the host cells against the fungal attack. On the other hand, the pre-treatment with BABA caused a stronger fluorescent of epidermal cells at the penetration sites compared to the pre-inoculation with the bacterial strains. Interestingly, the frequency of fluorescent cells by BABA, however, was lower than that by the bacterial strains. Based on the results it is suggested that the infection structures showing resistance reaction on the leaves of potato plants were different between by pre-inoculation with bacterial strains and by pre-treatment with BABA against the late blight pathogen.

• Korean journal of applied entomology
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• v.51 no.4
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• pp.349-356
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• 2012

Eicosanoid mediates various cellular immune responses in insects. This study aimed to discover its novel action on the modulation of hemocyte populations in response to an immune challenge. Upon bacterial challenge, the last instar larvae of the beet armyworm, Spodoptera exigua, increased their total hemocyte density in 2 h, and then decreased it to a basal hemocyte density level. This rapid increase in total hemocyte density was explained by an increase of plasmatocyte and spherulocyte densities. When larvae were treated with dexamethasone (a specific phospholipase $A_2$ ($PLA_2$) inhibitor), they did not show any increase in hemocyte density in response to bacterial challenge. However, the addition of arachidonic acid (a catalytic product of $PLA_2$) to larvae treated with dexamethasone recovered the up-regulation of hemocyte density in response to bacterial infection. Among eicosanoid, cyclooxygenase (COX), but not lipoxygenase (LOX), products seemed to mediate the increase of hemocyte density in response to bacterial infection because naproxene (a COX inhibitor) inhibited the hemocyte density increase, though esculetin (a LOX inhibitor) did not. Prostaglandin $E_2$, a COX product, significantly increased the hemocyte density even without bacterial infection. These results suggest that eicosaniod mediates a rapid increase in total hemocyte density in response to immune challenge.

• Fisheries and Aquatic Sciences
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• v.20 no.12
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• pp.31.1-31.11
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• 2017

Background: Liver-expressed antimicrobial peptide-2 (LEAP-2) is an important component of innate immune system in teleosts. In order to understand isoform-specific involvement and regulation of LEAP-2 genes in mud loach (Misgurnus mizolepis, Cypriniformes), a commercially important food fish, this study was aimed to characterize gene structure and expression characteristics of two paralog LEAP-2 isoforms. Results: Mud loach LEAP-2 isoforms (LEAP-2A and LEAP-2B) showed conserved features in the core structure of mature peptides characterized by four Cys residues to form two disulfide bonds. The two paralog isoforms represented a tripartite genomic organization, known as a common structure of vertebrate LEAP-2 genes. Bioinformatic analysis predicted various transcription factor binding motifs in the 5'-flanking regions of mud loach LEAP-2 genes with regard to development and immune response. Mud loach LEAP-2A and LEAP-2B isoforms exhibited different tissue expression patterns and were developmentally regulated. Both isoforms are rapidly modulated toward upregulation during bacterial challenge in an isoform and/or tissue-dependent fashion. Conclusion: Both LEAP-2 isoforms play protective roles not only in embryonic and larval development but also in early immune response to bacterial invasion in mud loach. The regulation pattern of the two isoform genes under basal and stimulated conditions would be isoform-specific, suggestive of a certain degree of functional divergence between isoforms in innate immune system in this species.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.79.2-80
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• 2003

To better understand plant defense responses against pathogen attack, we identified the transcription factor-encoding genes in the hot pepper Capsicum annuum that show altered expression patterns during the hypersensitive response raised by challenge with bacterial pathogens. One of these genes, Ca1244, was characterized further. This gene encodes a plant-specific Type IIIA - zinc finger protein that contains two Cys$_2$His$_2$zinc fingers. Ca1244 expression is rapidly and specifically induced when pepper plants are challenged with bacterial pathogens to which they are resistant. In contrast, challenge with a pathogen to which the plants are susceptible only generates weak Ca1244 expression. Ca1244 expression is also strongly induced in pepper leaves by the exogenous application of ethephon, an ethylene releasing compound. Whereas, salicylic acid and methyl jasmonate had moderate effects. Pepper protoplasts expressing a Ca1244-smGFP fusion protein showed Ca1244 localizes in the nucleus. Transgenic tobacco plants overexpressing Ca1244 driven by the CaMV 355 promoter show increased resistance to challenge with a tobacco-specific bacterial pathogen. These plants also showed constitutive upregulation of the expression of multiple defense-related genes. These observations provide the first evidence that an Type IIIA - zinc finger protein, Ca1244, plays a crucial role in the activation of the pathogen defense response in plants.

• Fisheries and Aquatic Sciences
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• v.18 no.2
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• pp.173-181
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• 2015

We identified the $Na^+-K^+-2Cl^-$ cotransporter 2 (NKCC2) cDNA isoform from starry flounder, Platichthys stellate. The NKCC2 cDNA encoded a polypeptide of 1,043 amino acids representing 12 putative transmembrane domains based on the bioinformatic topology prediction. In addition, starry flounder NKCC2 possessed highly conserved residues within transmembrane domain 4, known as an essential site for its function. End-point reverse transcription-polymerase chain reaction analysis revealed that the NKCC2 transcript was moderately expressed only in the anterior and posterior intestines and the rectum. The NKCC2 mRNA level in the rectum, but not in other segments, was significantly induced 3 days post Streptococcus parauberis challenge, indicating that excess salt may be transported into the rectum. Taken together, our data indicate that an S. parauberis infection could tip the intestinal fluid balance in favor of fluid accumulation, indicating that bacterial pathogens can interfere with intestinal osmotic balance and normal mucosal immune homeostasis.

• Korean Journal of Veterinary Service
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• v.44 no.4
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• pp.247-256
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• 2021

The recombinant lysozyme-HJL34 proteins were expressed and purified using commercial Escherichia (E.) coli expression system. Stx2e⁺ F18⁺ E. coli, Actinobacillus pleuropneumoniae (APP), Streptococcus (S.) suis, and Clostridium (C.) perfringens strains were isolated from pigs. The minimum inhibitory concentrations (MICs) of the recombinant lysozyme-HJP34 proteins were examined by means of the microtiter plate method, according to the NCCLS recommendations. The possibility of its as the alternatives to antibiotics was tested in piglets. The MICs were determined as 75 ㎍/mL, 300 ㎍/mL, 75 ㎍/mL, 35.5 ㎍/m against Stx2e⁺ F18⁺ E. coli, APP, S. suis, C. perfringens, respectively. A total of 25 piglets were divied 5 groups. The piglets in group A~C were fed with commercial feed and those in groups D, E were fed with commercial feedstuff. All piglets in groups B~E were challenged with virulent Stx2e⁺ F18⁺ E. coli, APP, S. suis strains. Groups C and D were treated with antimicrobial from 24 h after challenge. All piglets in group B died within 3 days after challenge. Among 5 piglets in groups C and D piglets, 80% survived after challenge. Among group E piglets, 60% were alive until the end of this study. Therefore, this study indicates that recombinant lysozyme-HJP34 proteins is a suitable possibility as a feed additive for reduction of diseases by bacterial pathogens in piglet feed.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.5
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• pp.696-706
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• 2011

The objective of this study was to characterize serum immunoglobulins and lymphocytes subpopulations in the peripheral blood mononuclear cells (PBMCs) of Holstein calves in response to lipopolysaccharide (LPS) challenge from Escherichia coli. Fourteen calves received subcutaneous injections of E. coli LPS at 10 weeks of age, and six calves were injected with saline as a control. The concentrations of total serum IgG and the relative amount of LPS-specific IgG in calves challenged with LPS were significantly higher (p<0.05) compared to control animals and LPS challenge significantly increased (p<0.05) the percentage of $CD5^+$ and $CD21^+$ T cells in PBMCs. Meanwhile, LPS challenge significantly increased (p<0.05, p<0.01) the percentage of $CD8^+$ and $CD25^+$ T cells in peripheral blood mononuclear cells (PBMC) at 7 and 14 Day-post LPS challenge (DPLC), respectively. The composition of $CD4^+CD25^+$ T cells and $CD8^+CD25^+$ T cells from calves challenged with LPS was also higher (p<0.05 and p = 0.562, respectively) than those of control calves at 14 DPLC. In conclusion, LPS challenge not only induces production of IgG with expression of B-cell immune response related cell surface molecules, but also stimulates activation of T-lymphocytes in PBMC. Our results suggest that LPS challenge in calves is a good model to elucidate cellular immune response against Gram-negative bacterial infections.