Hilário C Mantovani

Learn More
Previous work indicated that Streptococcus bovis HC5 had significant antibacterial activity, and even nisin-resistant S. bovis JB1 cells could be strongly inhibited. S. bovis HC5 inhibited a variety of Gram-positive bacteria and the spectrum of activity was similar to monensin, a commonly used feed additive. The crude extracts (ammonium sulfate(More)
Beef cattle have been fed ionophores and other antibiotics for more than 20 years to decrease ruminal fermentation losses (e.g methane and ammonia) and increase feed efficiency, and these improvements have been explained by an inhibition of gram-positive ruminal bacteria. Ionophores are not used to treat human disease, but there has been an increased(More)
The proteolytic activity of Pseudomonas fluorescens 07A was investigated, and was optimal on tryptone-calcium medium. N-acyl-homoserine lactones (AHLs) were not detected on supernatants of late-exponential and stationary-phase culture broths. Synthetic AHLs or bacterial cell extracts added to the medium did not influence growth or proteolytic activity(More)
Numerous bacteria coordinate gene expression in response to small signalling molecules in many cases known as acylhomoserine lactones (AHLs), which accumulate as a function of cell density in a process known as quorum sensing. This work aimed to determine if phenotypes that are important to define microbial activity in foods such as biofilm formation,(More)
Antimicrobial peptides have been suggested as an alternative to classical antibiotics in livestock production and bacteriocin-producing bacteria could be added to animal feeds to deliver bacteriocins in the gastrointestinal (GI) tract of ruminant and monogastric animals. In this study, viable (V) and heat-killed (HK) Streptococcus bovis HC5 cells were(More)
The aim of this work was to evaluate a quorum-quenching approach to identify functions regulated by quorum sensing in Enterobacter cloacae. We employed an aiiA transconjugant strain of E. cloacae that synthesizes a lactonase enzyme that hydrolyzes N-acyl homoserine lactone signaling molecules to compare bacterial phenotypes in the presence and absence of(More)
The objective of this study was to examine the effects of Tithonia diversifolia as a supplementary forage on dairy cow performance and methane production. Nine lactating Holstein × Zebu dairy cows (519 ± 53.3 kg of body weight and 66 ± 13.3 d in milk) were paired by milk yield (21.3 ± 2.34 kg/d) and body weight and randomly assigned to three dietary(More)
Quorum sensing regulates a variety of phenotypes in bacteria including the production of virulence factors. Salmonella spp. have quorum sensing systems mediated by three autoinducers (AI-1, AI-2, and AI-3). The AI-1-mediated system is incomplete in that the bacterium relies on the synthesis of signaling molecules by other microorganisms. This study aimed to(More)
Dietary protein plays a major role in ruminant nutrition, and protein supplementation is a widespread practice among farmers in the tropics. Ruminal bacteria are the main agents of dietary protein and amino acid degradation, yet few studies have focused on the isolation and characterization of hyper-ammonia-producing bacteria in animals fed tropical diets(More)
Streptococcus equinus (Streptococcus bovis) HC5 is a bacteriocinogenic lactic acid bacterium with simple growth requirements. The draft genome sequence of S. equinus HC5 consists of 1,846,241 bp, with a G+C content of 37.04%. In silico analysis indicated that S. equinus HC5 might be useful to control bacteria that are detrimental to livestock animals.