A novel serine protease, Sep1, from Bacillus firmus DS-1 has nematicidal activity and degrades multiple intestinal-associated nematode proteins

Abstract

Plant-parasitic nematodes (PPNs) cause serious harm to agricultural production. Bacillus firmus shows excellent control of PPNs and has been produced as a commercial nematicide. However, its nematicidal factors and mechanisms are still unknown. In this study, we showed that B. firmus strain DS-1 has high toxicity against Meloidogyne incognita and soybean cyst nematode. We sequenced the whole genome of DS-1 and identified multiple potential virulence factors. We then focused on a peptidase S8 superfamily protein called Sep1 and demonstrated that it had toxicity against the nematodes Caenorhabditis elegans and M. incognita. The Sep1 protein exhibited serine protease activity and degraded the intestinal tissues of nematodes. Thus, the Sep1 protease of B. firmus is a novel biocontrol factor with activity against a root-knot nematode. We then used C. elegans as a model to elucidate the nematicidal mechanism of Sep1, and the results showed that Sep1 could degrade multiple intestinal and cuticle-associated proteins and destroyed host physical barriers. The knowledge gained in our study will lead to a better understanding of the mechanisms of B. firmus against PPNs and will aid in the development of novel bio-agents with increased efficacy for controlling PPNs.

Isolation of bacterial inhibitory peptides from lactic acid bacteria of the piglet digestive tract and identification by proteomic test

“…La ornithine monooxygenase actúa como sideróforo A (SidA) y es una monooxigenasa dependiente de flavina que cataliza la hidroxilación dependiente de NAD (P) H y oxígeno de ornitina en la biosíntesis de sideróforos, que posteriormente se forma para generar los hidroxamatos quelantes de hierro del sideróforo pyoverdin, que limitan el uso de estos metales en la nutrición de Escherichia produciéndola muerte de la bacteria. Romero (2012) y Shirey (2013) reportaron que la ornithine monooxygenase interviene en el metabolismo al condicionar la acción de varios metales sobre la actividad enzimática y aumenta en presencia de Ca 2 + , K 2 + , Ba 2 + , Co 2 + y Ni 2 + poseyendo efectos fungicida, larvicida y quelante que impide la nutrición bacteriana de patógenos (Zohra, 2016;Geng, 2016;Cechova, 2016). La RNase J family beta-CASP ribonuclease actúa como una proteasa específica que causa destrucción celular de patógenos por su acción antibiótica, donde la acción de los iones magnesio indican resultados de la mutagénesis.…”

“…Los antibióticos son usados en pequeñas cantidades como promotores de creci-miento en la alimentación de cerdos los cuales a largo plazo producen contaminación y resistencia a los mismos --------- (Bhandari et al, 2010), en un mundo en el que la resistencia a los antimicrobianos constituye un problema global de gran relevancia para la salud pública (Del Coco, 2015). Existen microorganismos que producen sustancias potenciales para mejorar el desempeño y la salud de cerdos, esto es debido al efecto bactericida que mejora la eficiencia del aparato digestivo e incluso que pueden ser utilizados como probióticos (García et al, 2012) donde la mayoría de ellas son bacterias ácido láctico BAL, principalmente del género Lactobacillus, que generan productos extracelulares que pueden sustituir a los antibióticos (Cueto-Vigil et al, 2010;Kim et al, 2012) y pueden controlar bacterias patógenas gracias a la producción de sustancias como el ácido láctico y compuestos proteicos, conocidos como bacteriocinas (Zohra, 2016;Geng, 2016;Cechova, 2016;Xue-Yuan, 2015). Bajo este contexto, con el fin de solucionar la problemática formulada, se planteó como objetivo identificar molecularmente, sustancias proteicas de acción inhibidor de bacterias y antimicrobiana (bacteriocinas) producidas por bacterias ácido lácticas del tracto digestivo del lechón.…”

Insights into Antagonistic Interactions of Multidrug Resistant Bacteria in Mangrove Sediments from the South Indian State of Kerala

“…Plant-growth-promoting bacteria (PGPB) and probiotics such as B. firmus, Bacillus koreensis, and Bacillus toyonensis were also detected in the mangrove sediment. B. firmus promotes plant growth by protecting roots against plant pathogens [33] and serves as a bionematicide [34] by production of serine protease, which degrades vitals proteins associated with intestinal tissues and physical barriers [35]. B. koreensis has also been shown to have multiple desirable plant-growth-promotion properties such has IAA (indole-3-acetic acid) production, nitrogenase activity, and antifungal activity [36].…”

Isolation and Bioprocess Optimization of Halophilic and Alkaline Protease From Marine Streptomyces and Its Use As Contact Lens Cleaner

“…Enzyme activity was inhibited by PMSF even at the minimum concentration (2.5 mmol l − 1 ) as it strongly blocks the active site of the enzyme, which leads to complete loss of enzyme activity (Rao et al 1998). As PMSF is a known inhibitor of serine proteases (Geng et al 2016), it indicates that the isolated enzyme could be a serinetype protease. The enzyme was mostly stable in the presence of metal ions such as Cu 2+ , Hg 2+ , Zn 2+ , Ca 2+ , and Mg 2+ ions.…”