Ricardo Pinheiro de Souza Oliveira

Effect of different prebiotics on the fermentation kinetics, probiotic survival and fatty acids profiles in nonfat symbiotic fermented milk.

The simultaneous effects of different binary co-cultures of Lactobacillus acidophilus, Lactobacillus bulgaricus, Lactobacillus rhamnosus and Bifidobacterium lactis with Streptococcus thermophilus and of different prebiotics on the production of fermented milk were investigated in this paper. In particular, we determined and compared the kinetics of acidification of milk either as such or supplemented with 4% (w/w) maltodextrin, oligofructose and polydextrose, as well as the probiotic survival, chemical composition (pH, lactose, lactic acid and protein contents), fatty acids profile and conjugate linoleic acid (CLA) content of fermented milk after storage at 4 degrees C for 24 h. Fermented milk quality was strongly influenced both by the co-culture composition and the selected prebiotic. Depending on the co-culture, prebiotic addition to milk influenced to different extent kinetic acidification parameters. All probiotic counts were stimulated by oligofructose and polydextrose, and among these B. lactis always exhibited the highest counts in all supplemented milk samples. Polydextrose addition led to the highest post-acidification. Although the contents of the main fatty acids were only barely influenced, the highest amounts of conjugated linoleic acid (38% higher than in the control) were found in milk fermented by S. thermophilus-L. acidophilus co-culture and supplemented with maltodextrin.

Biogas production and valorization by means of a two-step biological process

The scope of this research work was to investigate biogas production and purification by a two-step bench-scale biological system, consisting of fed-batch pulse-feeding anaerobic digestion of mixed sludge, followed by methane enrichment of biogas by the use of the cyanobacterium Arthrospiraplatensis. The composition of biogas was nearly constant, and methane and carbon dioxide percentages ranged between 70.5-76.0% and 13.2-19.5%, respectively. Biogas yield reached a maximum value (about 0.4 m(3)(biogas)/kg COD(i)) at 50 days-retention time and then gradually decreased with a decrease in the retention time. Biogas CO(2) was then used as a carbon source for A. platensis cultivation either under batch or fed-batch conditions. The mean cell productivity of fed-batch cultivation was about 15% higher than that observed during the last batch phase (0.035+/-0.006 g(DM)/L/d), likely due to the occurrence of some shading effect under batch growth conditions. The data of carbon dioxide removal from biogas revealed the existence of a linear relationship between the rates of A. platensis growth and carbon dioxide removal from biogas and allowed calculating carbon utilization efficiency for biomass production of almost 95%.

Bacteriocin production by Bifidobacterium spp. A review

Bacteriocins are ribosomally-synthesized antibacterial peptides. These compounds are produced by a broad variety of different bacteria belonging mainly to the genus Bifidobacterium, to which health promoting properties have frequently been attributed. However, despite the fact that the identification of Bifidobacterium-associated bacteriocins was first reported in 1980 and that they exhibit antimicrobial activity against pathogenic microorganisms such as Listeria monocytogenes, Clostridium perfringens, and Escherichia coli, relatively little information is still available about the antimicrobial compounds produced by strains of this genus. More detailed understanding of the action mechanisms of these antimicrobials could allow us to determine the extent to which their production contributes to the probiotic properties of specific bifidobacteria strains and, potentially, be of crucial significance for ultimate preservation of functional foods or pharmaceutical applications. Here we review what is already known about their structure, classification, mode of action, functionality, immunity, production and purification.

Use of lactulose as prebiotic and its influence on the growth, acidification profile and viable counts of different probiotics in fermented skim milk.

Lactulose can be considered as a prebiotic, which is able to stimulate healthy intestinal microflora. In the present work, the use of this ingredient in fermented milk improved quality of skim milk fermented by Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus bulgaricus and Bifidobacterium lactis in co-culture with Streptococcus thermophilus. Compared to control fermentations without lactulose, the addition of such a prebiotic in skim milk increased the counts of all probiotics, with particular concern to B. lactis (bifidogenic effect), the acidification rate and the lactic acid acidity, and concurrently reduced the time to complete fermentation (t(pH4.5)) and the pH at the end of cold storage for 1 to 35 days.

Overview of Lactobacillus plantarum as a promising bacteriocin producer among lactic acid bacteria

Chemical preservatives have been traditionally used during the manufacturing of processed products. However, the continuous growing interest of consumers for fresh and natural products makes it necessary to search for alternative compounds. In this context, food industries have been widely using lactic acid bacteria (LAB) as natural preservatives, due to their ability to produce antibacterial compounds such as bacteriocins. Similarly, pharmaceutical industries have improved the use of these bacterial peptides, with antibacterial activity, trying to reduce the indiscriminate use of antibiotics in food products for human and animal consumption. Among LAB, Lactobacillus plantarum can be adapted to various niches thanks to its ability to ferment a wide range of carbohydrates. Additionally, it can be used as starter culture in food fermentations and as an ingredient for probiotic foods, contributing to the organoleptic characteristics of foods at the same time prolonging the shelf-life and safety of these products. The amount of valuable substances obtained from L. plantarum species isolated from different ecological niches is also worth noting, thus proving it to be one of the most important and versatile species among LAB.

KIAA1549: BRAF Gene Fusion and FGFR1 Hotspot Mutations Are Prognostic Factors in Pilocytic Astrocytomas

Abstract Up to 20% of patients with pilocytic astrocytoma (PA) experience a poor outcome. BRAF alterations and Fibroblast growth factor receptor 1 (FGFR1) point mutations are key molecular alterations in Pas, but their clinical implications are not established. We aimed to determine the frequency and prognostic role of these alterations in a cohort of 69 patients with PAs. We assessed KIAA1549:BRAF fusion by fluorescence in situ hybridization and BRAF (exon 15) mutations by capillary sequencing. In addition, FGFR1 expression was analyzed using immunohistochemistry, and this was compared with gene amplification and hotspot mutations (exons 12 and 14) assessed by fluorescence in situ hybridization and capillary sequencing. KIAA1549:BRAF fusion was identified in almost 60% of cases. Two tumors harbored mutated BRAF. Despite high FGFR1 expression overall, no cases had FGFR1 amplifications. Three cases harbored a FGFR1 p.K656E point mutation. No correlation was observed between BRAF and FGFR1 alterations. The cases were predominantly pediatric (87%), and no statistical differences were observed in molecular alterations–related patient ages. In summary, we confirmed the high frequency of KIAA1549:BRAF fusion in PAs and its association with a better outcome. Oncogenic mutations of FGFR1, although rare, occurred in a subset of patients with worse outcome. These molecular alterations may constitute alternative targets for novel clinical approaches, when radical surgical resection is unachievable.

Comparison of bacteriocins production from Enterococcus faecium strains in cheese whey and optimised commercial MRS medium

The production of bacteriocins from cheap substrates could be useful for many food industrial applications. This study aimed at determining the conditions needed for optimal production of enterocins SD1, SD2, SD3 and SD4 secreted by Enterococcus faecium strains SD1, SD2, SD3 and SD4, respectively. To our knowledge, this is the first use of cheese whey—a low-cost milk by-product—as a substrate for bacteriocin production by E. faecium; skimmed milk and MRS broths were used as reference media. This cheese manufacturing residue proved to be a promising substrate for the production of bacteriocins. However, the levels of secreted antimicrobial compounds were lower than those achieved by E. faecium strains in MRS broth. Bacteriocin production was affected strongly by physical and chemical factors such as growth temperature, time of incubation, pH, and the chemical composition of the culture medium. The optimal temperature and time of incubation supporting the highest bacteriocin production was determined for each strain. Different types, sources and amounts of organic nitrogen, sugar, and inorganic salts played an essential role in bacteriocin secretion. E. faecium strains SD1 and SD2—producing high bacteriocin levels both in cheese whey and skimmed milk—could be of great interest for potential applications in cheese-making.

Pediococcus spp.: An important genus of lactic acid bacteria and pediocin producers

Probiotics have gained increasing attention due to several health benefits related to the human digestive and immune systems. Pediococcus spp. are lactic acid bacteria (LAB) that are widely described as probiotics and characterized as coccus-shaped bacteria (arranged in tetrads), Gram-positive, non-motile, non-spore forming, catalase-negative, and facultative anaerobes. There are many Pediococcus strains that produce pediocin, an effective antilisterial bacteriocin. Pediocins are small, cationic molecules consisting of a conserved hydrophilic N-terminal portion containing the YGNGV motif and an amphiphilic or hydrophobic C-terminal variable portion. A number of studies have been developed with Pediococcus isolated from multiple biological niches to conduct fermentation processes for pediocin or Pediococcus cell production. This review gathers the most significant information about the cultivation, mode of action, and variability of bacteriocins produced by Pediococcus spp., emphasizing their applications in the areas of food and clinical practice. This updated panorama assists in delimiting the challenges that still need to be overcome for pediocin use to be approved for human consumption and the food industry.

Endovascular treatment of intracranial pial arteriovenous fistula

Medical School of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto SP, Brazil: Department of Internal Medicine, Division of Radiology; Department of Surgery, Division of Pediatric Neurosurgery. Intracranial pial arteriovenous fistulas (AVFs) are an extremely rare cerebrovascular disease, accounting for 1.6% of all intracranial vascular malformations. It has been recognized as a pathological entity distinct from the arteriovenous malformations (AVMs), due to the direct connection between the feeder artery and the draining vein, without an intervening true nidus. Pial AVFs differ from dural AVFs in that their arterial supply derive from pial and cortical arteries and they are not involved by the leaflets of the dura-mater. They are in their majority considered to be congenital, but they may also occur sporadically or in association with congenital hereditary vasculopathies. The pial AVFs have a significant morbid-mortality secondary to its rupture when not treated. We report a case of intracranial pial fistula in a 2 years-old patient presenting seizures since the neonatal period, emphasizing the angiographic findings and the results of the endovascular treatment.

Ferulic acid transformation into the main vanilla aroma compounds by Amycolatopsis sp. ATCC 39116

The wild strain Amycolatopsis sp. ATCC 39116 was explored in ferulic acid-based media to produce naturally the aroma components of the cured vanilla pod, namely vanillin, vanillic acid, and vanillyl alcohol. Other phenolic compounds (4-vinyl guaiacol, guaiacol, and protocatechuic acid) were also evaluated. The influence of medium composition, fermentation technology (batch or fed-batch), supplementation with vanillic acid, and inoculum concentration on ferulic acid biotransformation were evaluated. The results postulate the initial concentration of cell mass as the variable with the strongest impact on ferulic acid metabolization under the studied conditions. The highest amounts of vanillin and vanillic acid were achieved at intermediate values of cell mass. Vanillyl alcohol and protocatechuic acid were more closely linked to high cell mass concentrations. Conversely, 4-vinyl guaiacol reached its highest amount at the lowest amount of cell mass. Guaiacol was not detected in any case. Therefore, the initial cell concentration must be considered a critical parameter when using Amycolaptosis sp. ATCC 39116 for the production of vanillin and related compounds.