Production of exopolysaccharide from Klebsiella oxytoca: Rheological, emulsifying, biotechnological properties, and bioremediation applications.

Bacteria can synthesize a broad spectrum of multifunctional polysaccharides including extracellular polysaccharides (EPS). Bacterial EPS can be utilized in the food, pharmaceutical, and biomedical areas owing to their physical and rheological properties in addition to generally presenting low toxicity. From an ecological viewpoint, EPS are biodegradable and environment compatible, offering several advantages over synthetic compounds. This study investigated the EPS produced by Klebsiella oxytoca (KO-EPS) by chemically characterizing and evaluating its properties. The monosaccharide components of the KO-EPS were determined by HPLC coupled with a refractive index detector and GC-MS. The KO-EPS was then analyzed by methylation analysis, FT-IR and NMR spectroscopy to give a potential primary structure. KO-EPS demonstrated the ability to stabilize hydrophilic emulsions with various hydrophobic compounds, including hydrocarbons and vegetable and mineral oils. In terms of iron chelation capacity, the KO-EPS could sequester 41.9 % and 34.1 % of the most common iron states, Fe2+ and Fe3+, respectively. Moreover, KO-EPS exhibited an improvement in the viscosity of aqueous dispersion, being proportional to the increase in its concentration and presenting a non-Newtonian pseudoplastic flow behavior. KO-EPS also did not present a cytotoxic effect indicating that the KO-EPS could have potential applications as a natural thickener, bioemulsifier, and bioremediation agent.

Peptide PaDBS1R6 has potent antibacterial activity on clinical bacterial isolates and integrates an immunomodulatory peptide fragment within its sequence.

BACKGROUND: Resistant infectious diseases caused by gram-negative bacteria are among the most serious worldwide health problems. Antimicrobial peptides (AMPs) have been explored as promising antibacterial, antibiofilm, and anti-infective candidates to address these health challenges. MAJOR CONCLUSIONS: Here we report the potent antibacterial effect of the peptide PaDBS1R6 on clinical bacterial isolates and identify an immunomodulatory peptide fragment incorporated within it. PaDBS1R6 was evaluated against Acinetobacter baumannii and Escherichia coli clinical isolates and had minimal inhibitory concentration (MIC) values from 8 to 32 µmol L-1. It had a rapid bactericidal effect, with eradication showing within 3 min of incubation, depending on the bacterial strain tested. In addition, PaDBS1R6 inhibited biofilm formation for A. baumannii and E. coli and was non-toxic toward healthy mammalian cells. These findings are explained by the preference of PaDBS1R6 for anionic membranes over neutral membranes, as assessed by surface plasmon resonance assays and molecular dynamics simulations. Considering its potent antibacterial activity, PaDBS1R6 was used as a template for sliding-window fr agmentation studies (window size = 10 residues). Among the sliding-window fragments, PaDBS1R6F8, PaDBS1R6F9, and PaDBS1R6F10 were ineffective against any of the bacterial strains tested. Additional biological assays were conducted, including nitric oxide (NO) modulation and wound scratch assays, and the R6F8 peptide fragment was found to be active in modulating NO levels, as well as having strong wound healing properties. GENERAL SIGNIFICANCE: This study proposes a new concept whereby peptides with different biological properties can be derived by the screening of fragments from within potent AMPs.

A comprehensive review of Pfaffia glomerata botany, ethnopharmacology, phytochemistry, biological activities, and biotechnology.

ETHNOPHARMACOLOGICAL RELEVANCE: Pfaffia glomerata (Spreng.) Pedersen, Amaranthaceae, is found in South America, mainly in Brazil, where it is considered a species of great medicinal interest owing to its popular use as a tonic, aphrodisiac, anti-inflammatory, and analgesic. These properties can be attributed to the presence of the phytosteroid, 20-Hydroxyecdysone (ß-ecdysone), the main compound found in its roots. AIM OF THE REVIEW: This review aims to provide information about the botanical characteristics, ethnomedicinal uses, the phytochemistry, the biological activities, and the biotechnology of P. glomerata, an important species to local communities and groups researching medicinal plants of South America. MATERIALS AND METHODS: The information available on P. glomerata was collected from scientific databases (ScienceDirect, PubMed/MEDLINE, SciELO, and Scopus) until June 7, 2023, using the search terms "Pfaffia glomerata", "Pfaffia glomerata (Spreng.) Pedersen", and "Brazilian ginseng". The review includes studies that evaluated the botanical, ethnopharmacological, and phytochemical aspects, biological properties, nutraceutical uses, and the application of biotechnology for improving the biosynthesis of metabolites of interest. RESULTS: A total of 207 studies were identified, with 81 articles read in full. Seventy-six studies were included for qualitative synthesis. Overall, 40 compounds belonging to different classes are presented in this review, including ecdysteroids, triterpenes, saponins, flavonoids, anthraquinones, tannins, coumarins, alkaloids, and polysaccharides. Among them, flavonoids, anthraquinones, tannins, coumarins, and alkaloids were only putatively identified. ß-Ecdysone, triterpenes, saponins, and polysaccharides are the chemical components most frequently identified and isolated from P. glomerata and possibly responsible for ethnopharmacological use and the biological activities of this species, with important in vitro and in vivo activities, such as anti-inflammatory, antidepressant, aphrodisiac, analgesic, gastroprotective, antioxidant, and prebiotic. CONCLUSIONS: This review summarizes discussions about the P. glomerata species, highlighting its ethnopharmacological, chemical, biotechnological, and nutraceutical importance. New scientific studies on this species are encouraged in the search for new therapeutic molecules with pharmaceutical potential and nutraceutical applications.

Evaluation of antitumoral and antioxidant activities of the hydroalcoholic extract and fractions obtained from the fruit pericarp of Sapindus saponaria L.

The fruits of Sapindus saponaria L., popularly known as 'saboeiro', have been used in medicine. This study evaluated the antioxidant and antitumor activities of the hydroethanolic extract (HAE) and fractions obtained from the fruit pericarp of S. saponaria. The HAE was obtained from the S. saponaria fruit pericarp by maceration; this was followed by fractionation using reversed-phase solid-phase extraction, resulting in fractions enriched with acyclic sesquiterpenic oligoglycosides (ASOG) and saponins (SAP1, and SAP2), confirmed by mass spectrometry with electrospray ionization (ESI-QTOF-MS). The greatest citotoxic activity was observed with the SAP1 fraction against the CaCo2 cell line with a GI50 of 8.1 µg mL-1, while the SAP2 fraction had a GI50 of 13.6 µg mL-1 against CaCo2. The HAE demonstrated the greatest antioxidant activity. S. saponaria has potential therapeutic use in the pharmaceutical industry as a natural anti-oxidant or antitumor product.

Spatial structure of phytoplankton metacommunities and their functional groups in a neotropical floodplain / Estrutura espacial de metacomunidades fitoplanctônicas e seus grupos funcionais em uma planície de inundação neotropical

Abstract The spatial and temporal patterns and dynamics of biological community structure can be better understood through the lens of metacommunity theory, in which the effect of local (deterministic processes, ecological niche theory) and regional (stochastic processes, neutral theory) processes are evaluated as the main predictors of phytoplankton. The objective of this paper was to evaluate the effect of local environmental characteristics, spatial, and landscape predictors on the phytoplankton community in lakes of the Araguaia River floodplain. We evaluated the following questions: (i) What is the specific importance of physical and chemical water characteristics (local environmental predictors), dispersive processes (spatial predictors), and land use and occupancy (landscape predictors) in the phytoplankton metacommunity structure, both for taxonomic and functional groups? (ii) Does the buffer size used in land use and land cover measurement around the sampling units show differences in phytoplankton community prediction? All the predictors could explain the phytoplankton structure but the spatial were the most important. The buffers showed different predictive abilities, with taxonomic classification being related to larger sizes of buffers and functional groups the opposite. The great influence of spatial predictors can be explained by source-sink dynamics, where dispersal is so strong that it can diminish the effects of local predictors and guarantee a large flux of organisms to sink communities. In conclusion, dispersive processes have been shown to strongly influence the spatial structuring of the phytoplankton metacommunity and we highlight the need to consider buffers' size when assessing the landscape's effect on phytoplankton communities.

Resumo Os padrões espaciais e temporais e a dinâmica da estrutura da comunidade biológica podem ser compreendidos por meio das lentes da teoria de metacomunidades, no qual o efeito dos processos locais (processos determinísticos, teoria do nicho ecológico) e regionais (processos estocásticos, teoria neutra) são destacados como os principais preditores do fitoplâncton. O objetivo deste trabalho foi avaliar o efeito de preditores ambientais locais, espaciais e de paisagem sobre a comunidade fitoplanctônica em lagos da planície de inundação do Rio Araguaia. Avaliamos as seguintes questões: (i) Qual é a importância específica das características físicas e químicas da água (preditores ambientais locais), dos processos dispersivos (preditores espaciais) e do uso e ocupação do solo (preditores de paisagem) na estrutura da metacomunidade fitoplanctônica, tanto para grupos taxonômicos quanto funcionais? (ii) O tamanho do buffer usado na medição do uso e da ocupação do solo ao redor das unidades de amostragem mostra diferenças na previsão da comunidade fitoplanctônica? Todos os preditores explicaram a estrutura do fitoplâncton, mas os espaciais foram os mais importantes. Os buffers mostraram diferentes habilidades preditivas, com a classificação taxonômica sendo relacionada a tamanhos maiores de buffers e grupos funcionais, o oposto. A grande influência dos preditores espaciais pode ser explicada pela dinâmica fonte-sumidouro, em que a dispersão é tão forte que pode diminuir os efeitos dos preditores locais e garantir um grande fluxo de organismos para as comunidades de sumidouros. Em conclusão, foi demonstrado que os processos dispersivos influenciam fortemente a estruturação espacial da metacomunidade de fitoplâncton e destacamos a necessidade de considerar o tamanho dos buffers ao avaliar o efeito da paisagem sobre as comunidades de fitoplâncton.

Lentinus crinitus: Traditional use, phytochemical and pharmacological activities, and industrial and biotechnological applications.

The saprophytic basidiomycete Lentinus crinitus (L.) Fr is a Brazilian native fungus with pantropical occurrence. L. crinitus produces edible fruiting bodies with medicinal, nutritional, and biotechnological applications. The compounds from fungal fruiting bodies can be applied to the preparation of products in the food, cosmetic, biomedical, and pharmaceutical industries. Our aim was to review the literature on L. crinitus concerning its botanical description, geographical distribution, phytochemistry, pharmacological properties, nutritional value, and biotechnology potential (in vitro cultivation and enzyme production). Scientific search engines, including ScienceDirect, CAPES Journals Portal, Google Scholar, PubMed, SciELO, MEDLINE, LILACS, and SciFinder, were consulted to gather data on L. crinitus. The present review is an up-to-date and comprehensive analysis of the phytochemical compounds, phytopharmacological activities, and biotechnological value of L. crinitus. Extracts from L. crinitus have been reported to exhibit numerous in vitro pharmacological activities such as antioxidant, antifungal, antibacterial, antiviral, and anticancer. The substances in these extracts belong to different classes of chemical compounds such as polysaccharides, fatty acids, terpenes, phenolic acids, and flavonoids. Reviews on Brazilian native fungi are of great importance for scientific knowledge, with great applicability as a mirror for species of the same family. The ethnobotanical, phytochemical, pharmacological, ethnomedicinal, and biotechnological properties of L. crinitus highlighted in this review provide information for future studies and commercial exploitation, and reveal that this fungus has enormous potential for pharmaceutical, nutraceutical, biotechnological, and ecological applications.

Inulin extraction from Stevia rebaudiana roots in an autoclave.

Inulin is a polymer of d-fructose, characterized by the presence of a terminal glucose, and are a major component of Stevia rebaudiana roots. This type of polymer has nutritional properties and technological applications, such as fat substitutes in low-calorie foods and as the coating of pharmaceuticals. The aim of this study was to evaluate an alternative method for inulin extraction, in terms of extraction time and yield, since the traditional method of extraction under reflux is both time and energy consuming. Using the response surface methodology (RSM) with Box-Behnken design it was observed that the alternative extraction method using autoclave presented similar yields to the reflux-based method, but with a shorter extraction time, 121 °C by 17.41 min 1H Nuclear Magnetic Resonance and Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-ToF-MS) analysis showed that inulin crude extract from S. rebaudiana roots obtained by autoclave extraction had a higher degree of polymerization when compared to those obtained by the traditional method. Thus, it is concluded that the proposed method using an autoclave is a faster alternative for the extraction of inulin.

Valorization of Campomanesia xanthocarpa leaves: chemical composition and antioxidant activity of crude extract and fractions / Valorización de hojas de Campomanesia xanthocarpa: composición química y actividad antioxidante de extracto crudo y fracciones

Campomanesia xanthocarpa leaves are a byproduct of fruit production without studies on antioxidant activity. Thus, this study aimed to identify the antioxidant compounds of C. xanthocarpaleaves by ultra-high performance liquid chromatography coupled with electrospray ionization-quadrupole-time of flight-mass spectrometry (UHPLC-ESI/qTOF) and by different in vitro antioxidant methods. The crude extract of C. xanthocarpa leaves had a yield of 15.2% and only five out of 37 fractions of the crude extract had antioxidant activity. The crude extract presented greater antioxidant activity than the isolated fractions. The identified antioxidant compounds were phenolic acids (gallic acid and chlorogenic acid), flavonoids (quercetin and naringenin 7,4'-dimethoxy) and an organic acid (quinic acid). Leaves of C. xanthocarpa have high concentration of antioxidant compounds and it is a promising plant for the development of applications in the food, cosmetic, and pharmaceutical fields. The extraction of antioxidant compounds can add value to the productive chain of this plant.

Las hojas de Campomanesia xanthocarpa son un subproducto de la producción de frutos sin estudios sobre la actividad antioxidante. Así, este estudio tuvo como objetivo identificar los compuestos antioxidantes de las hojas de C. xanthocarpa mediante cromatografía líquida de ultra alta resolución acoplada con espectrometría de ionización-cuadrupolo-tiempo de vuelo-masa por electropulverización (UHPLC-ESI / qTOF) y mediante diferentes métodos antioxidantes in vitro. El extracto crudo de hojas de C. xanthocarpa tuvo un rendimiento del 15,2% y solo cinco de las 37 fracciones del extracto crudo tuvieron actividad antioxidante. El extracto crudo presentó mayor actividad antioxidante que las fracciones aisladas. Los compuestos antioxidantes identificados fueron ácidos fenólicos (ácido gálico y ácido clorogénico), flavonoides (quercetina y naringenina 7,4'-dimetoxi) y un ácido orgánico (ácido quínico). Las hojas de C. xanthocarpa tienen una alta concentración de compuestos antioxidantes y es una planta prometedora para el desarrollo de aplicaciones en los campos alimentario, cosmético y farmacéutico. La extracción de compuestos antioxidantes puede agregar valor a la cadena productiva de esta planta.

Low-cost alternative for the bioproduction of bioactive phenolic compounds of callus cultures from Cereus hildmannianus (K.) Schum.

The aim of this study was to establish a sustainable alternative callus culture of Cereus hildmannianus for the production and bioactive determination of phenolic compounds from this species. The conventional callus was cultivated using agar and Murashige and Skoog (MS) medium, while for the alternative culture the agar was replaced with a cotton support covered with filter paper and MS medium (incubated at 32 °C with photoperiod of 16 h), and the morphological characteristics and growth index were assessed (8 weeks). Extracts were obtained by maceration followed by partition, characterized by nuclear magnetic resonance - NMR and ultra-high performance liquid chromatography - UHPLC, quantified (phenolic compounds) by UV-Vis methods, and their antioxidant, antitumor activities, as well as cytotoxicity, were evaluated. The establishment of an alternative callus culture was carried out successfully. Characteristic signals of phenolic compounds were determined by NMR, and 46 compounds with fragment ions were identified using UHPLC analysis. The highest concentrations of phenolic compounds, and greatest antioxidant and antitumor activities, were obtained with the dichloromethane fractions of both callus tissue cultures, which were not cytotoxic. The callus culture from C. hildmannianus has shown promise as a source for the sustainable production of phenolic compounds with antioxidant and antiproliferative activities and thus, has potential use as a natural antitumor product.

Cereus peruvianus Mill. (Cactaceae) as a source of natural antioxidants: Phenolic compounds and antioxidant activity of cladode extracts in two collection periods.

The economic potential of the cactus species Cereus peruvianus Mill. (syn. C. hildmannianus K. Schum.) has already been demonstrated through the generation of products and patents. However, the phenolic compounds and antioxidant activity have not yet been evaluated. The aim of our study was to determine the total phenolic compounds, evaluate the antioxidant activity and characterize the phenolic compounds of cladode extracts from C. peruvianus grown in the southern region of Brazil, in two collection periods. Higher total content of phenolic compounds and antioxidant activity were detected in the cladode extract collected in 2016 than in the cladode extract collected in 2015. The profile of phenolic compounds identified five flavonoids that had not previously been reported in species of the genus Cereus. The phenolic compounds linked to antioxidant activities identified in the cladode extract from C. peruvianus support the use of this species in human food as a source of natural antioxidants.

Antimicrobial and antioxidant activities of secondary metabolites from endophytic fungus Botryosphaeria fabicerciana (MGN23-3) associated to Morus nigra L.

This study was to evaluate the biological activity of the extract of Botryosphaeria fabicerciana isolated from leaves of Morus nigra. The volatile compounds from the crude extract were analysed by GC-MS which demonstrate that mellein and ß-orcinaldehyde were are the major compounds. The best minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extract was observed against Gram-positive bacteria, with a MIC of 15.6 µg/mL towards B. cereus and MIC of 62.5 µg/mL towards S. aureus and B. subtilis. MBC values of 31.25 µg/mL, 62.5 µg/mL, and 250 µg/mL were observed towards B. cereus, B. subtilis, and S. aureus, respectively. The cytotoxicity analyses showed CC50 of 115 µg/mL. The crude extract showed antioxidant activity by the DPPH, ABTS, and FRAP assays. Therefore, the extract of the endophytic fungus presented biotechnological potential as an antibacterial and antioxidant agent.

Exopolysaccharides from Klebsiella oxytoca: anti-inflammatory activity

Abstract Exopolysaccharides (EPS) produced by Klebsiella oxytoca are of environmental, pharmaceutical, and medicinal interest. However, studies about the anti-inflammatory activity of EPS produced by this microorganism still remain limited. The aim of this study was to produce, characterize, and evaluate the anti-inflammatory activity of EPS from K. oxytoca in a pleurisy model. Colorimetric analysis revealed that precipitated crude exopolysaccharides (KEPSC) and deproteinated exopolysaccharides (KEPS) present high levels of total carbohydrates (65.57% and 62.82%, respectively). Analyses of uronic acid (7.90% in KEPSC and 6.21% in KEPS) and pyruvic acid (3.01% in KEPSC and 1.68% in KEPS) confirm that the EPS are acidic. Gas chromatography-mass spectrometry analyses demonstrated that the EPS consisted of rhamnose (29.83%), glucose (11.21%), galactose (52.45%), and mannose (6.50%). The treatment of an experimental pleurisy model in rats through subcutaneous administration of 50, 100, 200, and 400 mg/kg of KEPS decreased both the volume of inflammatory exudate and the number of leukocytes recruited to the pleural cavity. The present data showed that EPS production by K. oxytoca using the method described is easy to perform and results in a good yield. In addition, we show that KEPS exhibit anti-inflammatory activity when administered subcutaneously in rats.

Cereus hildmannianus (K.) Schum. (Cactaceae): Ethnomedical uses, phytochemistry and biological activities.

ETHNOPHARMACOLOGICAL RELEVANCE: Cereus hildmannianus (K.) Schum. (syn. C. peruvianus) is a native medicinal plant in the Neotropical region. C. hildmannianus cladodes extracts are used in folk medicine for weight loss, reducing cholesterol, low-density lipoprotein (LDL) levels, as diuretic and cardiotonic, and to treat various diseases, including pulmonary disorders, rheumatism, and in topical treatment for wounds and lithiasis. Fruits and flowers of C. hildmmanianus have high nutritional value. AIM OF THE REVIEW: In this review, previous reports on C. hildmannianus (syn. C. peruvianus) concerning its botanical description, geographical distribution, ethnomedicinal use, phytochemistry, in vitro and in vivo pharmacological properties, food benefits and plant biotechnology were summarized. MATERIALS AND METHODS: Scientific search engines, including ScienceDirect, Capes Journals Portal, Google Scholar, PubMed, Scielo, and Scifinder, were consulted to gather data on C. hildmannianus. The present review is an up-to-date and comprehensive analysis of phytochemical compounds, ethnomedicinal uses, phytopharmacological activities, and food value of cladodes, flowers, fruits, seeds, and tissue culture from C. hildmannianus. RESULTS: In traditional medicine, C.hildmannianus is used to treat various diseases, including pulmonary disorders, rheumatism, and in topical treatment for wounds and lithiasis. The extracts from the cladodes of C. hildmannianus exhibited numerous in vitro and in vivo pharmacological activities such as gastroprotective, antioxidant, antifungal, ovicidal, hemagglutinating and slimming, and anticancer activity. These extracts' substances belong to different classes of chemical compounds such as fatty acids, polysaccharides, terpenes, alkaloids, phenolic acids, and flavonoids CONCLUSIONS: Ethnomedicinal surveys have indicated the use of C. hildmannianus, an important medicinal plant in South America, for the treatment of various diseases. The ethnobotanical, phytochemical, pharmacological, and ethnomedicinal properties from various morphological parts of the plant of C. hildmannianus were highlighted in this review, which provides information for future studies, commercial exploration and reveals that this plant has a huge potential for pharmaceutical and nutraceutical applications.

Metabolic extract of the endophytic fungus Flavodon flavus isolated from Justicia brandegeana in the control of Alicyclobacillus acidoterrestris in commercial orange juice.

In this work, the antibacterial activity of a crude extract of the endophytic fungus Flavodon flavus (JB257), isolated from leaves of Justicia brandegeana, was evaluated against both the vegetative and sporulated forms of Alicyclobacillus acidoterrestris. The microdilution technique was performed in order to determine the antibacterial activity of the crude extract alone as well as in combination with the bacteriocin, nisin. The minimum inhibitory concentration (MIC) of the crude extract and nisin alone against A. acidoterrestris vegetative forms were 250 µg/mL and 31.5 µg/mL, respectively, while the minimum bactericidal concentrations (MBC) were 1000 µg/mL and 62.5 µg/mL,respectively. For A. acidoterrestris spores, treatment with the crude extract at a concentration of 500 µg/mL caused a 47% reduction in growth, while nisin at 62.5 µg/mL could reduce 100% of the growth. The in vitro evaluation of the crude extract combined with nisin against A. acidoterrestris by the Checkerboard method showed a synergistic interaction between the two compounds. In addition, greater selectivity towards bacterial cells over host cells, a human hepatocyte cell line, was achieved when the crude extract was combined with nisin, Using scanning electron microscopy, interferences in the cell membrane of A. acidoterrestris could be observed after treatment with the crude extract. The results presented in this study indicate that the crude extract of the endophyte F. flavus has biotechnological potential in the food industry, especially for the treatment of orange juices through the control of A. acidoterrestris.

Limonoid detection and profile in callus culture of sweet orange

Plant tissue culture has emerged as an important tool to produce bioactive compounds from various plant species, including the sustainable production of limonoids that are receiving considerable attention due to the benefits associated with human health such as anticancer activities. The purpose of the present study was to evaluate the capacity of limonoids aglycone production from callus culture from sweet orange cv. Pera (Citrus sinensis) seeds and identify the compounds produced in this cell line. Callus induction occurred in Murashige and Skoog medium supplemented with 2,4-dichlorophenoxyacetic (2,4-D), malt extract, agar and coconut water. For the analysis and identification of the limonoids, CG-MS-EI ion-positive mode and UPLC-QTOF-ESI were used operating in positive and negative mode. An intense peak corresponding to limonin appeared in the callus extracts at a retention time of 58.1 min. in CG-MS-EI and four major limonoids aglycone by positive ion mode UPLC-QTOF-ESI: limonin, nomilin, deacetylnomilin, and nomilinic acid. The culture medium was efficient at the bioproduction of limonoids aglycone in callus cultures of C. sinensis seeds. Therefore, data obtained from UPLC-QTOF-ESI proved its importance at identifying new compounds that benefit human health, and may assist future work in the identification of known or new limonoids in Citrus species and related genera.

Effects of fructans and probiotics on the inhibition of Klebsiella oxytoca and the production of short-chain fatty acids assessed by NMR spectroscopy.

Generally, the selection of fructans prebiotics and probiotics for the formulation of a symbiotic has been based on arbitrary considerations and in vitro tests that fail to take into account competitiveness and other interactions with autochthonous members of the intestinal microbiota. However, such analyzes may be a valuable step in the development of the symbiotic. The present study, therefore, aims to investigate the effect of lactobacilli strains and fructans (prebiotic compounds) on the growth of the intestinal competitor Klebsiella oxytoca, and to assess the correlation with short-chain fatty acids production. The short-chain fatty acids formed in the fermentation of the probiotic/prebiotic combination were investigated using NMR spectroscopy, and the inhibitory activities were assessed by agar diffusion and co-culture methods. The results showed that Lactobacillus strains can inhibit K. oxytoca, and that this antagonism is influenced by the fructans source and probably associated with organic acid production.

Anti-herpes activity of polysaccharide fractions from Stevia rebaudiana leaves.

The antiviral potential of natural polysaccharide compounds has been demonstrated, especially against enveloped viruses and members of the Herpesviridae family. Two polysaccharide fractions obtained from Stevia rebaudiana (Bertoni) leaves, that were active against Herpes simplex virus type 1 (HSV-1) were studied to investigate their mode of action. Both polysaccharides - SFW (crude faction) and SSFK (homogeneous alkaline fraction) - exerted antiviral effects on the initial stages of HSV-1 infection by inhibiting viral adsorption and penetration. When added after virus internalization, both fractions decreased plaque size. The effect of the fractions was confirmed by investigating viral glycoprotein expression. Based on the mode of action of the polysaccharides demonstrated in the present work and on their selectivity index, the polysaccharides obtained from S. rebaudiana could be an alternative treatment of infections caused by HSV-1.

Snake Venom Cathelicidins as Natural Antimicrobial Peptides.

Bioactive small molecules isolated from animals, plants, fungi and bacteria, including natural antimicrobial peptides, have shown great therapeutic potential worldwide. Among these peptides, snake venom cathelicidins are being widely exploited, because the variation in the composition of the venom reflects a range of biological activities that may be of biotechnological interest. Cathelicidins are short, cationic, and amphipathic molecules. They play an important role in host defense against microbial infections. We are currently facing a strong limitation on pharmacological interventions for infection control, which has become increasingly complex due to the lack of effective therapeutic options. In this review, we will focus on natural snake venom cathelicidins as promising candidates for the development of new antibacterial agents to fight antibiotic-resistant bacteria. We will highlight their antibacterial and antibiofilm activities, mechanism of action, and modulation of the innate immune response.

Treatment response in primary biliary cholangitis: The role of autoimmune hepatitis features.

INTRODUCTION AND AIM: Primary biliary cholangitis is a rare disease with scarce epidemiological data in Southern Europe. The authors aimed to evaluate treatment response in a cohort of patients. MATERIALS AND METHODS: This retrospective observational single-centre study included patients with diagnostic criteria of primary biliary cholangitis. Data on disease presentation, laboratory results, treatment and clinical endpoints were collected and analyzed. RESULTS: Fifty-three patients were included, 89% women, with mean age of 62±15 years at diagnosis. The majority was asymptomatic (49%), tested positive for antimitochondrial antibodies (96%) and had increased alkaline phosphatase (median=214U/L). 75% of the patients had liver histology and the majority were in Ludwig's stage I (42%). Autoimmune hepatitis (AIH) features were found in seven patients (13%). All were treated with ursodeoxycholic acid (UDCA) and 56% achieved biochemical response at one year; patients with AIH features exhibited steeper decreases in alkaline phosphatase (p=0.007) and reached the endpoint of 40% decrease in alkaline phosphatase more frequently (p=0.017). CONCLUSION: In conclusion a significant proportion of patients failed to achieve an adequate response to UDCA treatment. The response rate of patients with AIH features was better, which could be related to a different phenotype or to the potential impact of immunosuppressive agents.