Functional Foods, Nutraceuticals and Probiotics: A Focus on Human Health.

Functional foods are classified as traditional or staple foods that provide an essential nutritional level and share potentially positive effects on host health, including the reduction of disease by optimizing the immune system's ability to prevent and control infections by pathogens, as well as pathologies that cause functional alterations in the host. This chapter reviews the most recent research and advances in this area and discusses some perspectives on what the future holds in this area.

The expression of glycosyltransferases sdgA and sdgB in Staphylococcus epidermidis depends on the conditions of biofilm formation.

The Staphylococcus aureus SdrG protein is glycosylated by SdgA and SdgB for protection against its degradation by the neutrophil cathepsin G. So far, there is no information about the role of Staphylococcus epidermidis SdgA or SdgB in biofilm-forming; therefore, the focus of this work was to determine the distribution and expression of the sdrG, sdgA and sdgB genes in S. epidermidis under in vitro and in vivo biofilm conditions. The frequencies of the sdrG, sdgA and sdgB genes were evaluated by PCR in a collection of 75 isolates. Isolates were grown in dynamic (non-biofilm-forming) or static (biofilm-forming) conditions. The expression of sdrG, sdgA and sdgB was determined by RT-qPCR in cells grown under dynamic conditions (CGDC), as well as in planktonic and sessile cells from a biofilm and cells adhered to a catheter implanted in Balb/c mice. The sdrG and sdgB genes were detected in 100% of isolates, while the sdgA gene was detected in 71% of the sample (p < 0.001). CGDC did not express sdrG, sdgA and sdgB mRNAs. Planktonic and sessile cells expressed sdrG and sdgB, and the same was observed in cells adhered to the catheter. In particular, one isolate, capable of inducing a biofilm under treatment with cathepsin G, expressed sdrG and sdgB in planktonic and sessile cells and cells adhering to the catheter. This suggests that bacteria require biofilm conditions as an important factor for the transcription of the sdgA, sdgB and sdrG genes.

Exploring Antifouling Activity of Biosurfactants Producing Marine Bacteria Isolated from Gulf of California.

Biofouling causes major problems and economic losses to marine and shipping industries. In the search for new antifouling agents, marine bacteria with biosurfactants production capability can be an excellent option, due to the amphipathic surface-active characteristic that confers antimicrobial and antibiofilm activities. The aim of this study was to evaluate the antifouling activity of biosurfactants producing marine bacteria from the Gulf of California. The cell free culture supernatant (CFCS) of Bacillus niabensis (S-69), Ralstonia sp. (S-74) (isolated from marine sediment) and of B. niabensis (My-30) (bacteria associated to the sponge Mycale ramulosa) were screened for production of biosurfactants (using hemolysis and drop collapse test, oil displacement and emulsifying activity). The toxicity and antifouling activity were evaluated against biofoulers (bacteria forming biofilm and macrofoulers) both in laboratory and field assays. The results indicate that all bacteria were biosurfactant producers, but the higher capability was shown by B. niabensis (My-30) with high emulsifying properties (E24) of 71%. The CFCS showed moderate toxicity but were considered non-toxic against Artemia franciscana at low concentrations. In the antifouling assay, the CFCS of both strains of B. niabensis showed the best results for the reduction of the biofilm formation (up 50%) against all Gram-positive bacteria and most Gram-negative bacteria with low concentrations. In the field assay, the CFCS of B. niabensis (My-30) led to the reduction of 30% of biofouling compared to the control. The results indicate that the biosurfactant produced by B. niabensis (My-30) has promising antifouling activity.

Marine Sediment Recovered Salinispora sp. Inhibits the Growth of Emerging Bacterial Pathogens and other Multi-Drug-Resistant Bacteria.

Marine obligate actinobacteria produce a wide variety of secondary metabolites with biological activity, notably those with antibiotic activity urgently needed against multi-drug-resistant bacteria. Seventy-five marine actinobacteria were isolated from a marine sediment sample collected in Punta Arena de La Ventana, Baja California Sur, Mexico. The 16S rRNA gene identification, Multi Locus Sequence Analysis, and the marine salt requirement for growth assigned seventy-one isolates as members of the genus Salinispora, grouped apart but related to the main Salinispora arenicola species clade. The ability of salinisporae to inhibit bacterial growth of Staphylococcus epidermidis, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacer baumannii, Pseudomonas aeruginosa, and Enterobacter spp. was evaluated by cross-streaking plate and supernatant inhibition tests. Ten supernatants inhibited the growth of eight strains of S. epidermidis from patients suffering from ocular infections, two out of the eight showed growth inhibition on ten S. epidermidis strains from prosthetic joint infections. Also, it inhibited the growth of the remaining six multi-drug-resistant bacteria tested. These results showed that some Salinispora strains could produce antibacterial compounds to combat bacteria of clinical importance and prove that studying different geographical sites uncovers untapped microorganisms with metabolic potential.

Efecto in vitro del extracto crudo de un estreptomiceto causante de sarna común de papa en Sinaloa, México / In vitro effect of the crude extract of a potato common scab streptomycete in Sinaloa, Mexico

Abstract A strain isolated from potato common scab superficial lesions in El Fuerte Valley in northern Sinaloa, Mexico, was identified by 16S rRNA and morphological methods. Moreover, the effects of the crude extract of strain V2 was evaluated on radish and potato. The isolate was similar to Streptomyces acidiscabies in its morphological properties; however, the 16S rRNA gene sequence of strain V2 was neither 100% identical to this species nor to the streptomycetes previously reported in Sinaloa, Mexico. Strain V2 did not amplify any specific PCR products for genes necl and tomA, which have been found and reported in S. acidiscabies. Strain V2 produced a PCR product for the txtAB operon, which is related to the production of thaxtomin. In vitro assays using crude thaxtomin extract and a spore suspension of the organism caused necrotic symptoms on radish and potato, which were highly virulent in potato. This study reports that Streptomyces sp. V2 has a toxigenic region (TR) that is associated with the thaxtomin gene cluster.

Resumen Se aisló una cepa de una lesión superficial de sarna común de la papa en un ejemplar procedente del Valle del Fuerte, en el norte de Sinaloa, México. La cepa fue identificada por secuenciación del gen 16S ARNr, y por sus características morfológicas. Los efectos del extracto crudo de dicha cepa, llamada V2, fue evaluado en papa y rábano. El aislado fue similar a Streptomyces acidiscabies en sus características morfológicas, pero la secuencia del gen 16S ARNr de la cepa V2 no fue 100% idéntica a la de dicha especie, ni tampoco a las de cepas identificadas dentro de este taxón previamente en Sinaloa, México. La cepa V2 no amplificó los productos específicos de PCR de los genes nec1 y tomA, los cuales sí se han reportado en S. acidiscabies. La cepa V2 amplificó el producto de PCR para del operón txtAB, relacionado con la producción de taxtomina. A través de ensayos in vitro usando un extracto crudo de taxtomina y una suspensión de esporas del organismo aislado se verificó la producción de síntomas necróticos en rábano y papa, con mayor virulencia en esta última especie. Este estudio indica que Streptomyces sp. V2 tiene una región toxigénica (TR) asociada con el cluster de genes de taxtomina.

Differential Expression of the apsXRS System by Antimicrobial Peptide LL-37 in Commensal and Clinical Staphylococcus epidermidis Isolates.

The three-component apsXRS system senses and responds to cationic antimicrobial peptides (CAMPs), which induces the expression of the dlt operon and the genes mprF and vrafG, modifying the surface net charge in Staphylococcus epidermidis, resulting in the repulsion of CAMPs. The apsXRS system has been only studied in the S. epidermidis 1457 strain, and there are no studies of prevalence and level of expression of apsXRS in commensal and clinical isolates. From 60 isolates, those selected from commensal healthy skin (n = 20), commensal healthy conjunctive (n = 10), and clinical ocular infection (n = 30) presented the apsX, apsR, and apsS genes in their genomes. Constitutive expression of apsX, apsR, and apsS genes was determined by RT-qPCR in all isolates. It was found that expression of apsX, apsR, and apsS was 3.3-5.9-fold higher in commensal isolates stimulated with LL-37 (15 µg/mL) than in clinical isolates. Similarly, expression of the dlt operon and the genes mprF, and vraFG was 8-10-fold higher in commensal isolates than in clinical. However, LL-37 did not increase the addition of lysine in the phospholipids of the cytoplasmic membrane in any of the isolates. Mutations in the apsS loop region, apsR, and their promoter sequence were not found. These results demonstrated that apsXRS system is essential in all isolates for its constitutive expression; however, LL-37 caused an increase of apsXRS expression in commensal isolates, suggesting that S. epidermidis isolates do not respond in the same way to the presence of LL-37.

Genomic Insight into Three Marine Micromonospora sp. Strains from the Gulf of California.

Three actinomycete strains, designated BL1, BL4, and CV4, were isolated from sediment samples from the Gulf of California in 2009 together with nearly 300 other actinobacteria. Genome mining and analysis of their ∼6.4-Mb sequences confirmed the bioprospecting potential of these three bacteria belonging to the genus Micromonospora.

In vitro effect of the crude extract of a potato common scab streptomycete in Sinaloa, Mexico.

A strain isolated from potato common scab superficial lesions in El Fuerte Valley in northern Sinaloa, Mexico, was identified by 16S rRNA and morphological methods. Moreover, the effects of the crude extract of strain V2 was evaluated on radish and potato. The isolate was similar to Streptomyces acidiscabies in its morphological properties; however, the 16S rRNA gene sequence of strain V2 was neither 100% identical to this species nor to the streptomycetes previously reported in Sinaloa, Mexico. Strain V2 did not amplify any specific PCR products for genes nec1 and tomA, which have been found and reported in S. acidiscabies. Strain V2 produced a PCR product for the txtAB operon, which is related to the production of thaxtomin. In vitro assays using crude thaxtomin extract and a spore suspension of the organism caused necrotic symptoms on radish and potato, which were highly virulent in potato. This study reports that Streptomyces sp. V2 has a toxigenic region (TR) that is associated with the thaxtomin gene cluster.

Draft Genome Sequence of a Streptomycete Isolated from Potato Common Scab Lesions in the State of Sinaloa, Mexico.

Streptomyces sp. strain V2 was isolated from potato scab lesions in the state of Sinaloa, Mexico, and appears to be responsible for outbreaks in the area. The thaxtomin cluster was found in the ∼10.2-Mb genome; this cluster is associated with potato common scab disease in other potato pathogens.

Draft Genome Sequence of Two Marine Plantactinospora spp. from the Gulf of California.

Plantactinospora sp. strains BB1 and BC1 were isolated in 2009 from sediment samples of the Gulf of California from among almost 300 actinobacteria. Genome mining of their ∼8.5-Mb sequences showed the bioprospecting potential of these rare actinomycetes, providing an insight to their ecological and biotechnological importance.

Characterisation of the first actinobacterial group isolated from a Mexican extremophile environment.

The "Cave of Crystals" (aka 'Naica') in Chihuahua Mexico is a natural unique subterranean ecosystem which mainly consists of crystals made of calcium sulfate. The main system of caves are found at a depth of 300 meters (m) below sea level with crystals that range in size from a few centimeters to 15 m. The crystals date from nearly 400,000 years old and are thought to be formed when the cave was fully covered by water. At present time, this place shows a nearly constant temperature of 55 °C over the year and a humidity of 100 % which makes this place incomparable and unbearable to animal and/or human life. In the present study, two actinobacterial groups were isolated from within this system of caves and subjected to a systematic study to establish their phylogenetic relationship to microorganisms belonging to this vast group of Gram positive bacteria. Phenotypic properties, chemotaxonomic and 16S rRNA gene sequencing show that the microorganisms are members of the family Pseudonocardiaceae and are most closely related to the genus Prauserella. The present study is the first to report the isolation and presence of Actinobacteria or any other microbial form of life in this exceptional place. Moreover, this unexpected biodiversity can also provide an insight of the antibiotic resistome present in the isolates reported in this study.

Actinobacterial diversity from marine sediments collected in Mexico.

Seventeen different media known to support the growth and isolation of members of the class Actinobacteria were evaluated as selective isolation media for the recovery of this microbial group from marine sediments samples collected in the Gulf of California and the Gulf of Mexico. A general selective isolation procedure was employed for six sediments and nearly 300 actinomycetes were recovered from the selective isolation plates. Full 16S rRNA gene sequencing revealed that the isolates belonged to several actinobacterial taxa, notably to the genera Actinomadura, Dietzia, Gordonia, Micromonospora, Nonomuraea, Rhodococcus, Saccharomonospora, Saccharopolyspora, Salinispora, Streptomyces, "Solwaraspora" and Verrucosispora. Previous works on marine sediments have been restricted to the isolation of members of the genera Micromonospora, Rhodococcus and Streptomyces. This study provides further evidence that Actinobacteria present in marine habitats are not restricted to the Micromonospora-Rhodococcus-Streptomyces grouping. Indeed, this first systematic study shows the extent of actinobacterial diversity that can be found in marine sediments collected in Mexico and probably, worldwide.

Streptomyces sudanensis sp. nov., a new pathogen isolated from patients with actinomycetoma.

Nine strains isolated from mycetoma patients and received as Streptomyces somaliensis were the subject of a polyphasic taxonomic study. The organisms shared chemical markers consistent with their classification in the genus Streptomyces and formed two distinct monophyletic subclades in the Streptomyces 16S rRNA gene tree. The first subclade contained four organisms, including the type strain of S. somaliensis, and the second clade the remaining five strains which had almost identical 16S rRNA sequences. Members of the two subclades were sharply separated using DNA:DNA relatedness and phenotypic data which also showed that the subclade 1 strains formed an heterogeneous group. In contrast, the subclade 2 strains were assigned to a single genomic species and had identical phenotypic profiles. It is evident from these data that the subclade 2 strains should be recognised as a new species of Streptomyces. The name proposed for this new species is Streptomyces sudanensis sp. nov. The type strain is SD 504(T) (DSM = 41923(T) = NRRL B-24575(T)).

Reclassification of Nonomuraea flexuosa (Meyer 1989) Zhang et al. 1998 as Thermopolyspora flexuosa gen. nov., comb. nov., nom. rev.

A polyphasic study was undertaken to clarify the taxonomic position of Nonomuraea flexuosa DSM 41386(T). The distinct 16S rRNA gene sequence phyletic branch formed by this strain was equated with nine related monophyletic clades composed of representatives of the genera classified in the family Streptosporangiaceae. The organism produced a PCR product characteristic of this taxon when examined using a set of oligonucleotide primers specific for members of the family Streptosporangiaceae. Strain DSM 41386(T) could also be distinguished from representatives of the nine genera assigned to this family using a combination of chemotaxonomic, morphological and physiological properties. It is evident from the genotypic and phenotypic data that strain DSM 41386(T) is misclassified in the genus Nonomuraea and merits recognition as a monospecific genus within the family Streptosporangiaceae. It is proposed that the name Thermopolyspora flexuosa gen. nov., comb. nov., nom. rev. be used for this purpose, with the type strain DSM 41386(T) (=NRRL B-24348(T)).

Kitasatospora viridis sp. nov., a novel actinomycete from soil.

The taxonomic position of a rhizosphere isolate, strain 52108a(T), was determined using a polyphasic approach. The strain was found to have chemical and morphological properties consistent with its assignment to the genus Kitasatospora. An almost complete 16S rRNA gene sequence determined for the strain was aligned with corresponding sequences of representatives of the genus Kitasatospora and related taxa using three tree-making algorithms. The organism formed a distinct phyletic line within the Kitasatospora clade and was most closely related to Kitasatospora arboriphila (98.9 %), Kitasatospora kifunensis (99.0 %), Kitasatospora paracochleata (98.4 %) and Kitasatospora terrestris (98.2 %), but was readily distinguished from representatives of these species using a combination of phenotypic properties. The combined genotypic and phenotypic data show that the strain should be classified in the genus Kitasatospora as a novel species. The name proposed is Kitasatospora viridis sp. nov., with the type strain 52108a(T) (=AS 4.1878(T)=DSM 44826(T)).

Actinomadura mexicana sp. nov. and Actinomadura meyerii sp. nov., two novel soil sporoactinomycetes.

The taxonomic position of two soil isolates, strains A288(T) and A290(T) [provisionally assigned to the genus Actinomadura] was clarified in a polyphasic study. The organisms showed a combination of chemotaxonomic and morphological properties typical of actinomadurae. They also formed distinct phyletic lines in the 16S rRNA Actinomadura gene tree; strain A288(T) was associated with A. nitritigenes whereas strain A290(T) was closely related to a group that consisted of A. citrea, A. coerulea, A. glauciflava, A. luteofluorescens and A. verrucosospora. Strains A288(T) and A290(T) showed key phenotypic features which readily distinguish them from one another and from representatives of related validly described species of Actinomadura. It is proposed that the two organisms be classified as new species of the genus Actinomadura. The names proposed for the new taxa are Actinomadura mexicana (A290(T) = DSM 44485(T) = NRRL B-24203(T)), and Actinomadura meyerii (A288(T) = DSM 44485(T) = NRRL B-24203(T)).

Actinomadura catellatispora sp. nov. and Actinomadura glauciflava sp. nov., from a sewage ditch and soil in southern China.

Two soil isolates, strains 80-60T and 3.24T, were shown to have chemical and morphological properties consistent with their classification in the genus Actinomadura. The almost complete 16S rDNA sequences generated for the two organisms were aligned with available sequences of representatives of the genus Actinomadura and related taxa. It was apparent from the resultant phylogenetic trees that each of the strains formed a distinct phyletic line within the evolutionary radiation occupied by the genus Actinomadura. The two organisms could also be distinguished from one another and from representatives of all the validly described species of Actinomadura using a set of phenotypic properties. It is proposed that strains 3.24T (=AS 4.1522T =IFO 16341T) and 80-60T (=AS 4.1202T =IFO 14668T =JCM 16161T) be classified in the genus Actinomadura as Actinomadura catellatispora sp. nov. and Actinomadura glauciflava sp. nov., respectively.