Passive transfer of immunity from Tilapia antisera enhanced in-vitro phagocytosis of Aeromonas hydrophila in naïve Macrobrachium rosenbergii haemocytes

In this experiment, the quorum quenching gene ytnP of Bacillus licheniformis T-1 was cloned and expressed, and the effect against infection of Aeromonas hydrophila ATCC 7966 was evaluated in vitro and vivo. The BLAST results revealed a 99% sequence identity between the ytnP gene of T-1 and its homolog in B.subtilis sub sp. BSP1, and the dendroGram showed that the similarity in the YtnP protein in T-1 was 100% in comparison with B.subtilis 3610, which was categorized as the Aidc cluster of the MBL family. The AHL lactonase activity of the purified YtnP was detected as 1.097 ± 0.7 U/mL with C6-HSL as the substrate. Otherwise, purified YtnP protein could significantly inhibit the biofilm formation of A.hydrophila ATCC 7966 with an inhibition rate of 68%. The MIC of thiamphenicol and doxycycline hydrochloride against A. hydrophila reduced from 4 μg/mL and 0.5 μg/mL to 1 μg/mL and 0.125 μg/mL, respectively, in the presence of YtnP. In addition, YtnP significantly inhibited the expression of five virulence factors hem, ahyB, ast, ep, aerA of A. hydrophila ATCC 7966 as well (p < 0.05). The results of inhibition on virulence showed a time-dependence tendency, while the strongest anti-virulence effects were within 4–24 h. In vivo, when the YtnP protein was co-injected intraperitoneally with A. hydrophila ATCC 7966, it attenuated the pathogenicity of A. hydrophila and the accumulated mortality was 27 ± 4.14% at 96 h, which was significantly lower than the average mortality of 78 ± 2.57% of the Carassius auratus injected with 108 CFU/mL of A. hydrophila ATCC 7966 only (p < 0.001). In conclusion, the AHL lactonase in B. licheniformis T-1 was proven to be YtnP protein and could be developed into an agent against infection of A. hydrophila in aquaculture.

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Effect of Bacillus subtilis on Aeromonas hydrophila infection resistance in juvenile freshwater prawn, Macrobrachium rosenbergii (de Man)

Aquaculture International ◽

10.1007/s10499-012-9588-3 ◽

2012 ◽

Vol 21 (3) ◽

pp. 553-562 ◽

Cited By ~ 13

Author(s):

Mehran Avakh Keysami ◽

Masoumeh Mohammadpour

Keyword(s):

Bacillus Subtilis ◽

Aeromonas Hydrophila ◽

Macrobrachium Rosenbergii ◽

Freshwater Prawn ◽

Infection Resistance ◽

De Man

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Cross-talk among flesh-eating Aeromonas hydrophila strains in mixed infection leading to necrotizing fasciitis

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1523817113 ◽

2016 ◽

Vol 113 (3) ◽

pp. 722-727 ◽

Cited By ~ 38

Author(s):

Duraisamy Ponnusamy ◽

Elena V. Kozlova ◽

Jian Sha ◽

Tatiana E. Erova ◽

Sasha R. Azar ◽

...

Keyword(s):

Necrotizing Fasciitis ◽

Mixed Infection ◽

Aeromonas Hydrophila ◽

Case Fatality ◽

Host Immune System ◽

Complex Interactions ◽

Solid Media ◽

Multiple Strains ◽

Highly Virulent

Necrotizing fasciitis (NF) caused by flesh-eating bacteria is associated with high case fatality. In an earlier study, we reported infection of an immunocompetent individual with multiple strains of Aeromonas hydrophila (NF1–NF4), the latter three constituted a clonal group whereas NF1 was phylogenetically distinct. To understand the complex interactions of these strains in NF pathophysiology, a mouse model was used, whereby either single or mixed A. hydrophila strains were injected intramuscularly. NF2, which harbors exotoxin A (exoA) gene, was highly virulent when injected alone, but its virulence was attenuated in the presence of NF1 (exoA-minus). NF1 alone, although not lethal to animals, became highly virulent when combined with NF2, its virulence augmented by cis-exoA expression when injected alone in mice. Based on metagenomics and microbiological analyses, it was found that, in mixed infection, NF1 selectively disseminated to mouse peripheral organs, whereas the other strains (NF2, NF3, and NF4) were confined to the injection site and eventually cleared. In vitro studies showed NF2 to be more effectively phagocytized and killed by macrophages than NF1. NF1 inhibited growth of NF2 on solid media, but ExoA of NF2 augmented virulence of NF1 and the presence of NF1 facilitated clearance of NF2 from animals either by enhanced priming of host immune system or direct killing via a contact-dependent mechanism.

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STUDI BACILLUS FIRMUS SEBAGAI KANDIDAT PROBIOTIK DALAM MENGHADAPI Aeromonas hydrophila PADA MEDIA BUDIDAYA The Study of Bacillus firmus as Probiotic Candidate in Supressing Aeromonas hydrophila in Culture Media

SAINTEK PERIKANAN Indonesian Journal of Fisheries Science and Technology ◽

10.14710/ijfst.11.2.111-114 ◽

2016 ◽

Vol 11 (2) ◽

pp. 111

Author(s):

Alfabetian Harjuno Condro Haditomo ◽

Angela Mariana Lusiastuti ◽

Widanarni Widanarni

Keyword(s):

Aeromonas Hydrophila ◽

Pathogenic Bacteria ◽

Culture Media ◽

Inhibition Zone ◽

Probiotic Bacteria ◽

Bacterial Disease ◽

Second Phase ◽

Bacillus Firmus ◽

Culture Methods

ABSTRAK Pengendalian penyakit bakterial yang umum dilakukan dengan pemakaian antibiotik atau bahan kimia sudah tidak diperbolehkan lagi karena menimbulkan patogen yang resisten terhadap bahan kimia tersebut, terlebih jika penggunaan tidak sesuai dengan anjuran yang diberikan. Dampak negatif terhadap kesehatan konsumen berupa residu antibiotik juga menjadi pertimbangan yang harus diperhatikan. Manipulasi terhadap populasi mikroba yang berada di perairan guna pencegahan sebelum terjadinya serangan bakteri yang bersifat mematikan perlu dilakukan sebagaimana konsep probiotik sebagai biokontrol. Tujuan penelitian ini adalah menguji kandidat probiotik dalam menekan atau menghambat bakteri patogen Aeromonas hydrophila. Penelitian ini dilaksananakan dalam dua tahap. Tahap pertama adalah tahap pengujian bakteri kandidat probiotik secara in vitro menggunakan metode zona hambat dan kultur bersama pada media agar. Tahap kedua adalah uji tentang bakteri kandidat probiotik dengan patogen pada media budidaya. Hasil terbaik penelitian tahap pertama pada uji kultur bersama antara kandidat probiotik B. firmus dengan A. hydrophila pada skala in vitro adalah dengan penambahan probiotik B. firmus sebanyak 108 cfu/ml. Sedangkan pada penelitian tahap kedua didapatkan hasil berturut-turut perlakuan D dengan tingkat kelangsungan hidup (SR) mencapai 90%, perlakuan C dengan SR 75%, perlakuan A dengan SR 50% dan perlakuan K dengan SR 50%. Kata kunci: Bacillus firmus, probiotik, Aeromonas hydrophila, media budidaya ABSTRACT Controlling bacterial disease with the use of antibiotics or chemicals is no longer allowed as it results in pathogens that are resistant to the chemicals, especially when not in accordance with the recommendations provided. The negative impactsof the antibiotics residues on the consumers’ health also need to be considered. Manipulation of microbial populations present in the waters as preventation before the lethal attack of bacteria needs to be done which is in accordance with the concept of probiotics as biocontrol.The purpose of this study was to test the probiotic candidates in suppressing or inhibiting pathogenic bacteria Aeromonas hydrophila. This study was conducted in two stages. The first stage was to test a candidate probiotic bacteria in vitro using culture methods and inhibition zone on the media together. The second stage wasto test candidate probiotic bacteria to pathogens on the cultivation media. The best results in the first phase of the research is shared culture test between probiotic candidate B. FIRMUS with A. hydrophila on vitro scale is the addition of the probiotic B. FIRMUS 108 cfu / ml. While in the second phase of the research results obtained successively: treatment D with a survival rate (SR) reaches 90%, treatment C with SR 75%, treatment A with SR 50% and treatment K with SR 50%. Keywords: Bacillus FIRMUS, probiotics, Aeromonas hydrophila, media cultivation

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STUDIES ON THE PATHOGENESIS OF FEVER WITH INFLUENZAL VIRUSES

Journal of Experimental Medicine ◽

10.1084/jem.107.3.383 ◽

1958 ◽

Vol 107 (3) ◽

pp. 383-401 ◽

Cited By ~ 40

Author(s):

Elisha Atkins ◽

Wei Cheng Huang

Keyword(s):

Newcastle Disease ◽

Polymorphonuclear Leukocyte ◽

Influenza A ◽

Passive Transfer ◽

Endogenous Pyrogen ◽

Febrile Response ◽

Essential Step ◽

Intravenous Inoculation ◽

Intraperitoneal Inoculation

A substance with pyrogenic properties appears in the blood streams of rabbits made febrile by the intravenous inoculation of the PR8 strain of influenza A and Newcastle disease viruses (NDV). By means of a technique involving passive transfer of sera from animals given virus to recipient rabbits, the titer of circulating pyrogen was found to be closely correlated with the course of fever produced by virus. Certain properties of the pyrogen are described which differentiate it from the originally injected virus and suggest that the induced pyrogen is of endogenous origin. These properties resemble those of endogenous pyrogens occurring in other forms of experimental fever. The source of virus-induced pyrogen is unknown. In vitro incubation of virus with various constituents of the circulation did not result in the appearance of endogenous pyrogen. Granulocytopenia induced by HN2 failed to influence either fever or the production of endogenous pyrogen in rabbits injected with NDV. Similarly, the intraperitoneal inoculation of NDV into prepared exudates did not modify the febrile response. These findings do not lend support to the possibility that the polymorphonuclear leukocyte is a significant source of endogenous pyrogen in virus-induced fever. It is concluded that the liberation of an endogenous pyrogen from some as yet undefined source is an essential step in the pathogenesis of fever caused by the influenza group of viruses.

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Structural Insight Into Aeromonas Hydrophila AHL Synthase AhyI Driving Acyl-ACP Selective Recognition

10.21203/rs.3.rs-403119/v1 ◽

2021 ◽

Author(s):

Lei Jin ◽

Yu chen ◽

Wenge Yang

Keyword(s):

Aeromonas Hydrophila ◽

Acyl Chain ◽

Virulence Gene ◽

Kinetic Studies ◽

Homoserine Lactone ◽

Selective Recognition ◽

Acyl Donor ◽

Virulence Gene Expression ◽

Long Chain

Abstract Background: The gram-negative bacterium Aeromonas hydrophila as the major causative agent of the fish disease motile aeromonad septicemia, uses N-acyl-homoserine lactone quorum sensing signals to coordinate biofilm formation, motility and virulence gene expression in pathogens. Thus, AHL signaling pathway is considered as a therapeutic target against pathogenic A. hydrophila infection. AHL autoinducers biosynthesis in A. hydrophila are specifically catalyzed by an ACP-dependent AHL synthase AhyI using SAM and acyl-ACP as the precursors. Our previously reported AhyI protein heterologously expressed in E. coli strain showed the production characteristics of medium-long chain AHLs, although AhyI was only considered as a short-chain C4/C6-HSL synthase during the past two decades.Results: In this study, we carried out the in vitro biosynthetic assays of six AHL molecules and kinetic studies of recombinant AhyI with a panel of four linear acyl-ACPs. These resulting data all indicate that C4/C6-ACP are the native acyl substrates for AhyI against acyl-ACPs with longer linear chains as the non-native acyl donor. In an effort to further understand AhyI acyl-donor substrates preferences, we performed a structural comparison of three ACP-dependent LuxI homologs (TofI, BmaI1 and AhyI), and identified three key hydrophobic residues (I67, F125 and L157) as part of the acyl-chain binding pocket that confer AhyI to selectively recognize native C4/C6-ACP substrates. The predictions were further supported by computational Ala mutation assay.Conclusions: Our current studies redefined AhyI protein that is a multiple short- to long-chain AHL molecules synthase with longer acyl-ACPs (C8~C14) as the non-native substrates, and we also theorized that with knowledge of the key residues in AHL signal synthase AhyI to drive acyl-ACP selective recognition.

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Symbiotic bacteria associated to Prosthechea citrina, a Mexican endemic orchid

Revista Mexicana de Fitopatología Mexican Journal of Phytopathology ◽

10.18781/r.mex.fit.2004-2 ◽

2020 ◽

Vol 38 (3) ◽

Author(s):

Tomasita Santiago-Gerónimo ◽

Héctor Lozoya-Saldaña ◽

María Lourdes Rodríguez-Mejía

Keyword(s):

Aeromonas Hydrophila ◽

Symbiotic Bacteria

En el proceso de cultivo in vitro de tejidos de plantas, se presentan microorganismos potencialmente fitopatógenos y/o aparentemente contaminantes, que eventualmente ocasionan perdidas de material vegetal. La presente investigación tuvo como objetivo identificar a bacterias endófitas asociadas a Prosthechea citrina, una orquídea endémica de México, mediante el aislamiento, cultivo in vitro y secuenciación del gen 16S del ARN ribosomal de las cepas bacterianas. Se identificaron a Aeromonas hydrophila y Enterobacter sp. como simbiontes, no patogénicos, del bulbo y de base de hoja y a A. hydrophila en la parte media y el ápice foliar. Se evaluaron cuatro antibióticos para su control in vitro mediante el método de disco-placa, cuantificando el diámetro de crecimiento de la colonia. El mayor halo de inhibición, con significancia estadística, se obtuvo con oxitetraciclina para A. hydrophila y con ampicilina para Enterobacter sp. Se demuestra la presencia de bacterias endófitas, con especificidad de ubicación en el tejido, así como el antibiótico correspondiente que las inhibe.

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