scholarly journals A Novel Antimicrobial Peptide Sparanegtin Identified in Scylla paramamosain Showing Antimicrobial Activity and Immunoprotective Role In Vitro and Vivo

2021 ◽  
Vol 23 (1) ◽  
pp. 15
Author(s):  
Xuewu Zhu ◽  
Fangyi Chen ◽  
Shuang Li ◽  
Hui Peng ◽  
Ke-Jian Wang

The abuse of antibiotics in aquaculture and livestock no doubt has exacerbated the increase in antibiotic-resistant bacteria, which imposes serious threats to animal and human health. The exploration of substitutes for antibiotics from marine animals has become a promising area of research, and antimicrobial peptides (AMPs) are worth investigating and considering as potential alternatives to antibiotics. In the study, we identified a novel AMP gene from the mud crab Scylla paramamosain and named it Sparanegtin. Sparanegtin transcripts were most abundant in the testis of male crabs and significantly expressed with the challenge of lipopolysaccharide (LPS) or Vibrio alginolyticus. The recombinant Sparanegtin (rSparanegtin) was expressed in Escherichia coli and purified. rSparanegtin exhibited activity against Gram-positive and Gram-negative bacteria and had potent binding affinity with several polysaccharides. In addition, rSparanegtin exerted damaging activity on the cell walls and surfaces of P. aeruginosa with rougher and fragmented appearance. Interestingly, although rSparanegtin did not show activity against V. alginolyticus in vitro, it played an immunoprotective role in S. paramamosain and exerted an immunomodulatory effect by modulating several immune-related genes against V. alginolyticus infection through significantly reducing the bacterial load in the gills and hepatopancreas and increasing the survival rate of crabs.

Antibiotics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 162 ◽  
Author(s):  
Monica Francesca Blasi ◽  
Luciana Migliore ◽  
Daniela Mattei ◽  
Alice Rotini ◽  
Maria Cristina Thaller ◽  
...  

Sea turtles have been proposed as health indicators of marine habitats and carriers of antibiotic-resistant bacterial strains, for their longevity and migratory lifestyle. Up to now, a few studies evaluated the antibacterial resistant flora of Mediterranean loggerhead sea turtles (Caretta caretta) and most of them were carried out on stranded or recovered animals. In this study, the isolation and the antibiotic resistance profile of 90 Gram negative bacteria from cloacal swabs of 33 Mediterranean wild captured loggerhead sea turtles are described. Among sea turtles found in their foraging sites, 23 were in good health and 10 needed recovery for different health problems (hereafter named weak). Isolated cloacal bacteria belonged mainly to Enterobacteriaceae (59%), Shewanellaceae (31%) and Vibrionaceae families (5%). Although slight differences in the bacterial composition, healthy and weak sea turtles shared antibiotic-resistant strains. In total, 74 strains were endowed with one or multi resistance (up to five different drugs) phenotypes, mainly towards ampicillin (~70%) or sulfamethoxazole/trimethoprim (more than 30%). Hence, our results confirmed the presence of antibiotic-resistant strains also in healthy marine animals and the role of the loggerhead sea turtles in spreading antibiotic-resistant bacteria.


2020 ◽  
Vol 64 (12) ◽  
Author(s):  
Jitender Yadav ◽  
Sana Ismaeel ◽  
Ayub Qadri

ABSTRACT Polymyxin B, used to treat infections caused by antibiotic-resistant Gram-negative bacteria, produces nephrotoxicity at its current dosage. We show that a combination of nonbactericidal concentration of this drug and lysophosphatidylcholine (LPC) potently inhibits growth of Salmonella and at least two other Gram-negative bacteria in vitro. This combination makes bacterial membrane porous and causes degradation of DnaK, the regulator of protein folding. Polymyxin B-LPC combination may be an effective and safer regimen against drug-resistant bacteria.


2021 ◽  
Vol 8 ◽  
Author(s):  
An Liu ◽  
Wenyuan Shi ◽  
Dongdong Lin ◽  
Haihui Ye

C-type allatostatins (C-type ASTs) are a family of structurally related neuropeptides found in a wide range of insects and crustaceans. To date, the C-type allatostatin receptor in crustaceans has not been deorphaned, and little is known about its physiological functions. In this study, we aimed to functionally define a C-type ASTs receptor in the mud crab, Scylla paramamosian. We showed that C-type ASTs receptor can be activated by ScypaAST-C peptide in a dose-independent manner and by ScypaAST-CCC peptide in a dose-dependent manner with an IC50 value of 6.683 nM. Subsequently, in vivo and in vitro experiments were performed to investigate the potential roles of ScypaAST-C and ScypaAST-CCC peptides in the regulation of ecdysone (20E) and methyl farnesoate (MF) biosynthesis. The results indicated that ScypaAST-C inhibited biosynthesis of 20E in the Y-organ, whereas ScypaAST-CCC had no effect on the production of 20E. In addition, qRT-PCR showed that both ScypaAST-C and ScypaAST-CCC significantly decreased the level of expression of the MF biosynthetic enzyme gene in the mandibular organ, suggesting that the two neuropeptides have a negative effect on the MF biosynthesis in mandibular organs. In conclusion, this study provided new insight into the physiological roles of AST-C in inhibiting ecdysone biosynthesis. Furthermore, it was revealed that AST-C family peptides might inhibit MF biosynthesis in crustaceans.


2018 ◽  
Vol 16 (5) ◽  
pp. 341-348
Author(s):  
On-Anong SOMSAP

Antibiotic resistance bacteria has become an increasing problem now today due to many factors. This study investigates the efficacy of Prismatomeris tetrandra K. Schum root extract as a new source of antibacterial activity for antibiotic resistant bacteria using agar well diffusion method. The results showed that S. aureus TISTR517 exhibited more sensitivity to P. tetrandra K. Schum root extract than other Gram-positive bacteria indicator strains. On the other hand, Gram-negative bacteria exhibited resistance to P. tetrandra K. Schum root extract. The study further showed the activity between P. tetrandra K. Schum root extract and gentamycin (10 µg), it revealed that MRSA142 was resistant to gentamycin (10µg) but sensitive to P. tetrandra K. Schum root extract. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was evaluated by using S. aureus TISTR517 and MRSA142 as indicator strains. The MIC value was 0.59 mg/mL and 1.17 mg/mL for S. aureus TISTR517 and MRSA142, respectively. MBC assay demonstrated that the MBC value was 9.75 mg/mL and 150 mg/mL for S. aureus TISTR517 and MRSA142 respectively. The mode of action was investigated with the presence of P. tetrandra K. Schum root extract in the culture broth. The action of P. tetrandra K. Schum root extract was revealed of bacteriostatic activity due to the Optical density (OD) at 600 nm and Colony-Forming Units (CFU) of indicator strains were continuously decreased.


PLoS ONE ◽  
2018 ◽  
Vol 13 (9) ◽  
pp. e0204325
Author(s):  
Junguo Liu ◽  
Ming Zhao ◽  
Wei Song ◽  
Lingbo Ma ◽  
Xiu Li ◽  
...  

Antibiotics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 896
Author(s):  
Nikoletta Szemerédi ◽  
Annamária Kincses ◽  
Katerina Rehorova ◽  
Lan Hoang ◽  
Noemi Salardón-Jiménez ◽  
...  

The emergence of drug-resistant pathogens leads to a gradual decline in the efficacy of many antibacterial agents, which poses a serious problem for proper therapy. Multidrug resistance (MDR) mechanisms allow resistant bacteria to have limited uptake of drugs, modification of their target molecules, drug inactivation, or release of the drug into the extracellular space by efflux pumps (EPs). In previous studies, selenoesters have proved to be promising derivatives with a noteworthy antimicrobial activity. On the basis of these results, two series of novel selenoesters were synthesized to achieve more potent antibacterial activity on Gram-positive and Gram-negative bacteria. Fifteen selenoesters (eight ketone-selenoesters and seven cyano-selenoesters) were investigated with regards to their efflux pump-inhibiting, anti-quorum-sensing (QS), and anti-biofilm effects in vitro. According to the results of the antibacterial activity, the ketone-selenoesters proved to be more potent antibacterial compounds than the cyano-selenoesters. With regard to efflux pump inhibition, one cyano-selenoester on methicillin-resistant S. aureus and one ketone-selenoester on Salmonella Typhimurium were potent inhibitors. The biofilm inhibitory capacity and the ability of the derivatives to disrupt mature biofilms were noteworthy in all the experimental systems applied. Regarding QS inhibition, four ketone-selenoesters and three cyano-selenoesters exerted a noteworthy effect on Vibrio campbellii strains.


2020 ◽  
Vol 21 (7) ◽  
pp. 2297
Author(s):  
Dongdong Lin ◽  
Yujie Wei ◽  
Haihui Ye

Oxytocin (OT)/vasopressin (VP) signaling system is important to the regulation of metabolism, osmoregulation, social behaviours, learning, and memory, while the regulatory mechanism on ovarian development is still unclear in invertebrates. In this study, Spot/vp-like and its receptor (Spot/vpr-like) were identified in the mud crab Scylla paramamosain. Spot/vp-like transcripts were mainly expressed in the nervous tissues, midgut, gill, hepatopancreas, and ovary, while Spot/vpr-like were widespread in various tissues including the hepatopancreas, ovary, and hemocytes. In situ hybridisation revealed that Spot/vp-like mRNA was mainly detected in 6–9th clusters in the cerebral ganglion, and oocytes and follicular cells in the ovary, while Spot/vpr-like was found to localise in F-cells in the hepatopancreas and oocytes in the ovary. In vitro experiment showed that the mRNA expression level of Spvg in the hepatopancreas, Spvgr in the ovary, and 17β-estradiol (E2) content in culture medium were significantly declined with the administration of synthetic SpOT/VP-like peptide. Besides, after the injection of SpOT/VP-like peptide, it led to the significantly reduced expression of Spvg in the hepatopancreas and subduced E2 content in the haemolymph in the crabs. In brief, SpOT/VP signaling system might inhibit vitellogenesis through neuroendocrine and autocrine/paracrine modes, which may be realised by inhibiting the release of E2.


The Condor ◽  
2003 ◽  
Vol 105 (2) ◽  
pp. 358-361 ◽  
Author(s):  
Andréa M. A. Nascimento ◽  
Luciana Cursino ◽  
Higgor Gonçalves-Dornelas ◽  
Andrea Reis ◽  
Edmar Chartone-Souza ◽  
...  

Abstract We evaluated the antibiotic resistance of bacteria isolated from cloacal swabs of wild birds collected with mist nets in the Jequitinhonha river valley, in the state of Minas Gerais, Brazil. A total of 191 isolates from 19 individuals of 16 species was obtained and tested for resistance to five antibiotics. At Salto da Divisa 97% of the isolates exhibited a resistant phenotype, and resistance to more than one antibiotic was frequent (71%). At Jequitinhonha 36% of isolates were resistant, but 94% showed resistance to only one antibiotic. Of the five antibiotics tested, resistance to ampicillin was most frequent (in both areas), whereas kanamycin resistance was found in only one isolate. The data here obtained and other data reported in the literature show that the general premise that antibiotic-resistant bacteria arise primarily in hospitals or animal farms should be reconsidered. Bactérias Gram-Negativas Resistentes a Antibióticos em Aves da Mata Atlântica Brasileira Resumo. Avaliamos a resistência a antibióticos de bactérias isoladas por swab cloacal em aves selvagens capturadas com redes de neblina em duas regiões do Vale do Rio Jequitinhonha, Minas Gerais, Brasil. Foram obtidos 191 isolados de 19 indivíduos de 16 espécies e foi testada a resistência desses isolados a cinco antibióticos. Em Salto da Divisa, 97% dos isolados exibiram fenótipo resistente e foi freqüente (71%) a resistência a mais de um antibiótico. Em Jequitinhonha, 36% dos isolados exibiram fenótipo resistente, dos quais 94% apresentaram resistência a apenas um antibiótico. Em ambas as áreas, a maioria dos isolados apresentou resistência à ampicilina, enquanto somente um único isolado foi resistente à canamicina. Os dados aqui obtidos e outros relatados na literatura mostram que a premissa geral de que bactérias resistentes a antibióticos surgem principalmente em hospitais ou fazendas de animais deve ser reconsiderada.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mark A. T. Blaskovich ◽  
Alysha G. Elliott ◽  
Angela M. Kavanagh ◽  
Soumya Ramu ◽  
Matthew A. Cooper

Abstract Acne is a common skin affliction that involves excess sebum production and modified lipid composition, duct blockage, colonization by bacteria, and inflammation. Acne drugs target one or more of these steps, with antibiotics commonly used to treat the microbial infection for moderate to severe cases. Whilst a number of other acne therapies are purported to possess antimicrobial activity, this has been poorly documented in many cases. We conducted a comparative analysis of the activity of common topical acne drugs against the principal etiological agent associated with acne: the aerotolerant anaerobic Gram-positive organism Propionibacterium acnes (recently renamed as Cutibacterium acnes). We also assessed their impact on other bacteria that could also be affected by topical treatments, including both antibiotic-sensitive and antibiotic-resistant strains, using broth microdilution assay conditions. Drugs designated specifically as antibiotics had the greatest potency, but lost activity against resistant strains. The non-antibiotic acne agents did possess widespread antimicrobial activity, including against resistant strains, but at substantially higher concentrations. Hence, the antimicrobial activity of non-antibiotic acne agents may provide protection against a background of increased drug-resistant bacteria.


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