Impact on human health of microorganisms present in fermented dairy products: An overview

Fermented dairy products provide nutrients in our diet, some of which are produced by the action of microorganisms during fermentation. These products can be populated by a diverse microbiota that impacts the organoleptic and physicochemical characteristics foods as well as human health. Acidification is carried out by starter lactic acid bacteria (LAB) whereas other LAB, moulds, and yeasts become dominant during ripening and contribute to the development of aroma and texture in dairy products. Probiotics are generally part of the nonstarter microbiota, and their use has been extended in recent years. Fermented dairy products can contain beneficial compounds, which are produced by the metabolic activity of their microbiota (vitamins, conjugated linoleic acid, bioactive peptides, and gamma-aminobutyric acid, among others). Some microorganisms can also release toxic compounds, the most notorious being biogenic amines and aflatoxins. Though generally considered safe, fermented dairy products can be contaminated by pathogens. If proliferation occurs during manufacture or storage, they can cause sporadic cases or outbreaks of disease. This paper provides an overview on the current state of different aspects of the research on microorganisms present in dairy products in the light of their positive or negative impact on human health. © 2015 María Fernández et al.The work at the Spanish author’s laboratories was mainly financed through the projects AGL2010-16525 and INIA RM2010-00017-00-00 from the Ministry of Economy and Competitiveness (Spain).Peer Reviewe

Maximize Resolution or Minimize Error? Using Genotyping-By-Sequencing to Investigate the Recent Diversification of Helianthemum (Cistaceae)

A robust phylogenetic framework, in terms of extensive geographical and taxonomic sampling, well-resolved species relationships and high certainty of tree topologies and branch length estimations, is critical in the study of macroevolutionary patterns. Whereas Sanger sequencing-based methods usually recover insufficient phylogenetic signal, especially in recently diversified lineages, reduced-representation sequencing methods tend to provide well-supported phylogenetic relationships, but usually entail remarkable bioinformatic challenges due to the inherent trade-off between the number of SNPs and the magnitude of associated error rates. The genus Helianthemum (Cistaceae) is a species-rich and taxonomically complex Palearctic group of plants that diversified mainly since the Upper Miocene. It is a challenging case study since previous attempts using Sanger sequencing were unable to resolve the intrageneric phylogenetic relationships. Aiming to obtain a robust phylogenetic reconstruction based on genotyping-by-sequencing (GBS), we established a rigorous methodological workflow in which we i) explored how variable settings during dataset assembly have an impact on error rates and on the degree of resolution under concatenation and coalescent approaches, ii) assessed the effect of two extreme parameter configurations (minimizing error rates vs. maximizing phylogenetic resolution) on tree topology and branch lengths, and iii) evaluated the effects of these two configurations on estimates of divergence times and diversification rates. Our analyses produced highly supported topologically congruent phylogenetic trees for both configurations. However, minimizing error rates did produce more reliable branch lengths, critically affecting the accuracy of downstream analyses (i.e. divergence times and diversification rates). In addition to recommending a revision of intrageneric systematics, our results enabled us to identify three highly diversified lineages in Helianthemum in contrasting geographical areas and ecological conditions, which started radiating in the Upper Miocene.España, MINECO grants CGL2014- 52459-P and CGL2017-82465-PEspaña, Ministerio de Economía, Industria y Competitividad, reference IJCI-2015-2345

Impaired Virulence and In Vivo Fitness of Colistin-Resistant Acinetobacter baumannii

4 páginas, 2 figuras. Presentado en parte: 20 º Congreso Europeo de Microbiología Clínica y Enfermedades Infecciosas, Resumen 1389, Viena, Austria, 10-13 de abril de 2010.Acinetobacter baumannii (American Type Culture Collection strain 19606) acquires mutations in the pmrB gene during the in vitro development of resistance to colistin. The colistin-resistant strain has lower affinity for colistin, reduced in vivo fitness (competition index, .016), and decreased virulence, both in terms of mortality (0% lethal dose, 6.9 vs 4.9 log colony-forming units) and survival in a mouse model of peritoneal sepsis. These results may explain the low incidence and dissemination of colistin resistance in A. baumannii in clinical settings.This work was supported by the European Development Regional Fund “A way to achieve Europe” (ERDF); the Spanish Network for the Research in Infectious Diseases (REIPI RD06/0008), Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación, Spain; and the Autonomous government of Madrid (COMBACT S-BIO-0260/2006, L.R.).Peer reviewe

Past vegetation dynamics to infer holocene climate changes in Tenerife and La Gomera, Canary Islands

Oceanic islands in the low latitudes, as the Canary Islands, are generally considered to have been well buffered from the climate change of the Quaternary period. However, questions remain about whether past climatic changes on Atlantic islands are synchronic with those occurring in Africa and the Mediterranean coast or if the climate remained stable during the Holocene. Here we used fossil pollen and charcoal time series on Tenerife and La Gomera in order to: 1) provide the first inter-island picture of vegetation dynamics through the last 9600 years of this important biodiverse region of Europe; 2) detect the vegetation sensitivity, mainly tree communities, to past climatic changes; and, 3) provide evidences for human-induced changes at this potentially highly informative point. Preliminary analyses suggest very little climate change for the period 4000 years to present, but this requires confirmation by reference to additional coring sites. In La Gomera, we found strong evidences of a shift towards drier conditions at around 5500 years ago. The general vegetation pattern observed was a decrease in hygrophilous trees (Canarian palm and willow) and an expansion of Morella-Erica woody heath. Our results provide the first evidence to suggest that the general Northern Africa and Mediterranean shift towards drier conditions may be traced in the Canary Islands

Role of COQ4 on mitochondrial DNA maintenance

Resumen del póster presentado en Mitochondrial Medicine, celebrado en Hinxton (Inglaterra) del 09 al 11 de mayo de 2018.Coenzyme Q (CoQ) is a lipidic molecule composed by a hydroquinone head and an isoprenoid chain. Since its discovery, several functions have been assigned to CoQ, being the transfer of electrons from complexes I and II to complex III in the mitochondrial respiratory chain the best known. CoQ also receives electrons from other dehydrogenases involved in different cellular processes and it is a potent membrane antioxidant. CoQ is endogenously synthesized by a set of enzymes forming a biosynthetic complex in the mitochondrial inner membrane, which has been mostly studied in yeast models. Defects in any of the genes coding for these proteins result in reduced levels of CoQ and, consequently, defects in energy production. COQ4 is one of the proteins involved in CoQ biosynthesis, but its exact enzymatic activity is still unknown. COQ4 KO HEK 293T-Rex/Flp-In cells generated by CRISPR/Cas9, as well as patient fibroblasts carrying mutations in COQ4 show the accumulation of a yet uncharacterised biosynthetic intermediate that lacks redox activity. Two candidate molecules have emerged from mass spectrometry analysis performed to identify this intermediate. On the other hand, the KO cells show a surprising phenotype related to mtDNA metabolism which may be due either to the lack of de novo synthesis of CoQ, to the biosynthetic complex instability itself, to the presence of the intermediate, or to a different and yet not characterized role of COQ4. Altogether, these results indicate a possible double function of the COQ4 protein

Searching for glycosylated natural products in actinomycetes and identification of novel macrolactams and angucyclines

Many bioactive natural products are glycosylated compounds in which the sugar components usually participate in interaction and molecular recognition of the cellular target. Therefore, the presence of sugar moieties is important, in some cases essential, for bioactivity. Searching for novel glycosylated bioactive compounds is an important aim in the field of the research for natural products from actinomycetes. A great majority of these sugar moieties belong to the 6-deoxyhexoses and share two common biosynthetic steps catalyzed by a NDP-D-glucose synthase (GS) and a NDP-D-glucose 4,6-dehydratase (DH). Based on this fact, seventy one Streptomyces strains isolated from the integument of ants of the Tribe Attini were screened for the presence of biosynthetic gene clusters (BGCs) for glycosylated compounds. Total DNAs were analyzed by PCR amplification using oligo primers for GSs and DHs and also for a NDP-D-glucose-2,3-dehydratases. Amplicons were used in gene disruption experiments to generate non-producing mutants in the corresponding clusters. Eleven mutants were obtained and comparative dereplication analyses between the wild type strains and the corresponding mutants allowed in some cases the identification of the compound coded by the corresponding cluster (lobophorins, vicenistatin, chromomycins and benzanthrins) and that of two novel macrolactams (sipanmycin A and B). Several strains did not show UPLC differential peaks between the wild type strain and mutant profiles. However, after genome sequencing of these strains, the activation of the expression of two clusters was achieved by using nutritional and genetic approaches leading to the identification of compounds of the cervimycins family and two novel members of the warkmycins family. Our work defines a useful strategy for the identification new glycosylated compounds by a combination of genome mining, gene inactivation experiments and the activation of silent biosynthetic clusters in Streptomyces strains

Influenza and Pertussis Maternal Vaccination Coverage and Influencing Factors in Spain : a Study Based on Primary Care Records Registry

The purpose was to determine the coverage of maternal vaccination against influenza and pertussis, and the characteristics associated with being vaccinated, in a health area of Catalonia, Spain. Some 36,032 anonymized and computerized clinical records registries of pregnant women from Primary Care Centres (e-CAP database) were analysed, from between 2015 and 2018. Vaccination coverage and the association with sociodemographic variables and clinical conditions were estimated using a Poisson regression model. Maternal vaccination coverage against influenza ranged between 11.9% in 2015 and 6.8% in 2018, following a decreasing trend (p < 0.001). Coverage with the tetanus toxoid, diphtheria toxoid, and acellular pertussis vaccine varied between 49.8% in 2016 and 79.4% in 2018, following an increasing trend (p < 0.001). Having living children and suffering from obesity were factors associated with not being vaccinated against both infections. The predictive variables of vaccination against influenza were diabetes (IRR: 2.17, 95% CI: 1.42-3.30) and asthma (IRR: 2.05, 95% CI: 1.76-2.38); and for pertussis, it was asthma (IRR: 1.10, 95% CI: 1.03-1.17). Different socio-demographic factors and chronic conditions in pregnant women were associated with maternal vaccination, and which will have to be taken into account in clinical practice when implementing strategies to improve the coverage of the programme

Antiguos bosques de las Islas Canarias: métodos y técnicas para la reconstrucción de la vegetación

La Paleoecología es el estudio de las relaciones entre los organismos del pasado y los ambientes en los que vivían, mediante el análisis de fósiles y de los sedimentos en los que dichos fósiles se han preservado (Birks y Birks, 1980). Los fósiles son restos de organismos del pasado o indicadores de su actividad que se preservan con el paso del tiempo. Los fósiles de origen vegetal, en particular, se utilizan para reconstruir la vegetación del pasado y para determinarla influencia que los factores geológicos, climáticos, bióticos o antrópicos han tenido sobre las comunidades vegetales a lo largo del tiempo. Existen numerosos tipos de restos vegetales que pueden encontrarse en secuencias sedimentarias y que sirven para identificar las especies vegetales que habitaban en una determinada zona en el pasado. De acuerdo con su tamaño podemos diferenciar los macrofósiles vegetales, es decir aquellos que pueden ser identificados bajo la lupa (hojas, flores, frutos, semillas, maderas, carbones, etc.) y los microfósiles vegetales (granos de polen, esporas de helechos y briófitos, fitolitos, diatomeas, etc.), cuyo tamaño es tan pequeño que necesitan ser observados al microscopio. Otros fósiles de origen vegetal se pueden utilizar como indicadores de incendios ocurridos en el pasado (carbones, esporas de hongos asociadas a materiales quemados), o indicadores que proliferan como resultado de las actividades humanas,por ejemplo con la eutrofización de lagos (algas), la presencia de herbívoros domésticos (esporas fúngicas), o el incremento de incendios (carbones), además de indicadores de cambios en las propiedades físico-químicas de los lagos como resultado de cambios climáticos (diatomeas, algas)(Smol et al., 2001). Junto con los indicadores fósiles se suelen utilizar otros indicadores paleoambientales que implican el estudio de la propiedades físicas y químicas de los sedimentos. Los análisis geoquímicos indican procesos de erosión, alternancia de periodos húmedos y secos, o variaciones en los niveles de ciertos elementos químicos que a su vez pueden relacionarse con la contaminación antrópica. Las medidas de la susceptibilidad magnética detectan variabilidad en los procesos erosivos, y pueden asociarse a modificaciones de la cobertura vegetal o a determinados fenómenos climáticos. Otra propiedad de los sedimentos es la proporción de isótopos estables, que puede usarse como indicador de la temperatura del pasado, la aridez, y la concentración de CO2 atmosférico (Anderson et al., 2007). Por último, es esencial proveer de un marco temporal a las secuencias que contienen los fósiles para poder interpretar los procesos ambientales de forma ordenada en el tiempo. Para ello se aplican diferentes métodos de datación (datación radiométrica, paleomagnetismo, termoluminiscencia, o bioestratigrafía), dependiendo del material y del periodo de edad aproximado que se pretenda datar. La técnica más utilizada para el Holoceno (los últimos 11500 años de historia de La Tierra) es la datación por radiocarbono, basada en la tasa de descomposición radiactiva del carbono-14 (14C)que se encuentra en todos los organismos vivos (Roberts, 1998), y que se puede aplicar sobre materiales diversos (madera, carbones, semillas, huesos, dientes, conchas, fibras vegetales, etc.