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Water kefir is a sparkling, slightly acidic fermented beverage made from sugar, water, and water kefir grains, which are a mixture of yeast and bacteria. These grains produce a variety of fermentation compounds such as lactic acid, acetaldehyde, acetoin, ethanol and carbon dioxide. In this study, a high-throughput sequencing technique was used to characterize the bacterial composition of the original water kefir from which potential probiotics were obtained. We studied the bacterial diversity of both water kefir grains and beverages. DNA was extracted from three replicate samples of both grains and beverages using the Powerlyzer Microbial Kit. The hypervariable V1-V2 region of the bacterial 16S ribosomal RNA gene was amplified to prepare six DNA libraries. Between 1.4M and 2.4M base-pairs were sequenced for the library. In total, 28721971 raw reads were obtained from all the samples. Estimated species richness was higher in kefir beverage samples compared to grain samples. Moreover, a higher level of microbial alpha diversity was observed in the beverage samples. Particularly, the predominant bacteria in beverages were Anaerocolumna and Ralstonia, while in grains Liquorilactobacillus dominated, with lower levels of Leuconostoc and Oenococcus. Although the bacterial diversity in kefir grains was low because only three genera were the most represented, all of them are LAB bacteria with the potential to serve as probiotics in the artificial feeding of bees.

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La rotura espontánea de bazo es una complicación infrecuente pero muy grave de la mononucleosis infecciosa. Dada la urgencia con la que suele presentarse tal situación, la esplenectomía suele ser la opción quirúrgica más utilizada. Presentamos el caso de un paciente en el que con el diagnóstico de rotura esplénica espontánea se somete a laparoscopia diagnóstica en la que se consigue la preservación del bazo con buena evolución clínica. A la luz de este paciente, consideramos que, en caso de estabilidad clínica y hematomas subcapsulares de bazo, la laparoscopia con preservación esplénica es una opción viable y con buenos resultados. (provisto por Infomedic International)

Spontaneous rupture of the spleen is a rare but very serious complication of infectious mononucleosis. Given the urgency with which such a situation usually presents, splenectomy is usually the most used surgical option. We present the case of a patient diagnosed with spontaneous splenic rupture who underwent diagnostic laparoscopy in which spleen preservation was achieved with good clinical evolution. In the light of this patient, we consider that, in the case of clinical stability and subcapsular haematomas of the spleen, laparoscopy with splenic preservation is a viable option with good results. (provided by Infomedic International)

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Abstract We evaluated the microbial composition of water kefir grains and beverage overthe course of one year to determine whether the number and type of microorganisms changedover the time. Bacteria and yeast colonies with different morphologies were isolated fromwater kefir and their antimicrobial activity was evaluated against Paenibacillus larvae andAscosphaera apis. A chemical characterization of kefir was also carried out. Our results con-firmed that bacteria and yeasts were more numerous in kefir grains compared with those in thebeverage. The counts of microorganisms declined, although an important microbial community was still present in kefir after the long storage period. Eleven strains which inhibited bee pathogens were isolated from kefir. Genotypic results demonstrated that these isolates included Lentilactobacillus hilgardii, Lentilactobacillus buchneri and Saccharomyces cerevisiae. Thus, water kefir may be an innovative source of potential probiotic strains for bee nutrition in order to control honeybee diseases.

Resumen Evaluamos la composición microbiana del kéfir de agua durante un ano para determinar si la cantidad y el tipo de microorganismos cambiaban con el tiempo. Se aislaron colonias de bacterias y de levaduras con diferentes morfologías, y su actividad antimicrobiana se evaluó frente a Paenibacillus larvaey Ascosphaeraapis. También se realizó una caracterización química del kéfir. Nuestros resultados confirmaron que las bacterias y las levaduras eran más numerosas en los gránulos de kéfir en comparación con la parte líquida. Los recuentos de microorganismos disminuyeron, aunque una cantidad igualmente importante se encontró en el kéfir después de un año. Se aislaron del kéfir once cepas que inhibieron los mencionados patógenos de abejas. Los resultados genotípicos demostraron que estos aislamientos eran Lentilactobacillus hilgardii, Lentilactobacillus buchneri y Saccharomyces cerevisiae. Por lo tanto, el kéfir de agua podría ser una fuente innovadora de potenciales cepas probióticas para contribuir a la nutrición y sanidad de las abejas.

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We evaluated the microbial composition of water kefir grains and beverage over the course of one year to determine whether the number and type of microorganisms changed over the time. Bacteria and yeast colonies with different morphologies were isolated from water kefir and their antimicrobial activity was evaluated against Paenibacillus larvae and Ascosphaera apis. A chemical characterization of kefir was also carried out. Our results confirmed that bacteria and yeasts were more numerous in kefir grains compared with those in the beverage. The counts of microorganisms declined, although an important microbial community was still present in kefir after the long storage period. Eleven strains which inhibited bee pathogens were isolated from kefir. Genotypic results demonstrated that these isolates included Lentilactobacillus hilgardii, Lentilactobacillus buchneri and Saccharomyces cerevisiae. Thus, water kefir may be an innovative source of potential probiotic strains for bee nutrition in order to control honeybee diseases.

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This work aimed to evaluate the whole-organism and cellular level responses to different combinations of water temperature and salinity of the notothenioid Patagonotothen cornucola at the end of the yolk-sac larval stage. Egg masses of the species were collected in the wild and then maintained at natural water conditions (4 °C and 30 PSU). Newly hatched larvae were placed in aquaria with different combinations of water temperature (4 °C, 12 °C, and 16 °C) and salinity (15 and 30 PSU) during four days before yolk sac absorption. Larvae exposed to 12 °C grew more in length than those exposed to 16 °C, but yolk volume was more reduced in larvae exposed to 16 °C than those exposed to 4 °C and 30 PSU than of 15 PSU. In addition, a higher proportion of larvae exposed to 12 °C and 15 PSU completely absorbed their yolk. Whereas the more tolerant larvae to high temperatures were those exposed to 16 °C and 30 PSU, lipid peroxidation and protein oxidation were highest at natural and at 12 °C and 30 PSU conditions, respectively. The nutritional status (as standardized DNA/RNA index-sRD -) was low in all cases, even at natural conditions (average sRD ~ 1). Our study suggests that, in the context of climate change, the mortality rate of yolk-sac larvae of P. cornucola would not increase due to temperature or salinity stress. However, indirect effects (such as habitat degradation or changes in food availability) would be critical after complete absorption of the yolk.

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No estamos solos. Bacterias, hongos, parásitos y virus habitan cualquier parte de nuestro organismo y pueden cumplir funciones biológicas importantes, bien sea benéficas o dañinas. Conocerlos es fundamental para un manejo adecuado. Con las herramientas que utiliza el Grupo de Investigaciones Microbiológicas se pueden identificar la presencia del microorganismo y los marcadores moleculares de interés para la salud, como los relacionados con la resistencia a antibióticos, lo que aporta una información muy útil para el manejo de los pacientes.

We are not alone. Bacteria, fungi, parasites and viruses inhabit any part of our body and can perform important biological functions, either beneficial or harmful. Knowing them is essential for proper management. With the tools used by the Microbiological Research Group, the presence of the microorganism and molecular markers of interest for health, such as those related to antibiotic resistance, can be identified, which provides very useful information for patient management.

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A phylogenomic study conducted with different bioinformatic tools such as TYGS, REALPHY and AAI comparisons revealed a high rate of misidentified Streptomyces albus genomes in GenBank. Only 9 of the 18 annotated genomes available in the public database were correctly identified as S. albus species. The pangenome of the nine in silico confirmed S. albus genomes was almost closed. Lignocellulosic agroresidues were a common niche among strains of the S. albus clade while carbohydrate active enzymes (CAZymes) were highly conserved. Relevant enzymes for cellulose degradation such as beta glucosidases belonging to the GH1 family, a GH6 cellulase and a monooxygenase AA10-CBM2 were encoded by all S. albus genomes. Among them, one GH1 glycosidase would be regulated by CebR. However, this regulatory mechanism was not confirmed for other genes related to cellulose degradation. Based on AntiSMASH predictions, the core secondary metabolome of S. albus encompassed a total of 23 biosynthetic gene clusters (BGCs), where 4 were related to common metabolites within Streptomyces genus. Species specific BGCs included those related to pseudouridimycin and xantholipin. Additionally, four BGCs encoded putative derivatives of ibomycin, the lasso peptide SSV-2086, the lanthipeptide SapB and the terpene isorenieratene. Known metabolites could not be assigned to ten BGCs and three clusters did not match with any previously described BGC. The core genome of S. albus retrieved from nine closely related genomes revealed a high potential for the discovery of novel bioactive metabolites and underexplored regulatory genomic elements related to lignocellulose deconstruction.

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The selection of fast-growing and high-yield-producing strains is required to satisfy the market demand on fungal food supplements. To that aim, three strains deposited in our collection as G. lucidum and G. oregonense were screened for polysaccharide production and biomass yield. Ganoderma strains deposited as G. lucidum were identified as G. sessile and G. lingzhi by nuc rDNA internal transcribed spacer ITS1-5.8S-ITS2 (ITS) and translation elongation factor 1-α (TEF1-α) phylogenies. The identity of G. oregonense was confirmed by molecular phylogeny and biogeography. Additionally, mycelial antagonism confirmed species differentiation, and strains were further distinguished by morphology and protein profiles. Biomass and polysaccharide yields of G. sessile were clearly different from those of G. lingzhi and G. oregonense in both liquid culture and solid-state fermentation. The maximum polysaccharide yield (4.52 ± 0.83 g L-1) for G. sessile was obtained from submerged cultures at day 9. G. sessile also achieved the highest linear growth in lignocellulosic solid substrates. Consequently, basidiomata were successfully obtained by solid-state fermentation in polypropylene bags, whereas G. lingzhi and G. oregonense mushrooms were not produced in artificial solid substrates. G. sessile, a species frequently collected in America, showed to be a promising polysaccharide producer for the manufacture of dietary supplements.

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The Argentine hake, Merluccius hubbsi, is one of the most important fishing species in the Argentine Sea due to its great abundance and high-quality meat. The study of the nutritional condition is widely used to determine the physiological state of the fish larvae and to estimate their survival possibilities. The larval nutritional condition reflects the environmental conditions to which they have been exposed and represents a useful instrument to determine favourable nursery areas. It also provides tools for the comprehensive management of a population subjected to fishing exploitation. This study aimed to determine potential differences in the nutritional condition of M. hubbsi larvae from the two fishing stocks (Northern and Southern) of the species. The authors assessed the nutritional condition of larvae captured during the 2012 main reproductive peak in the nursery areas of each population. Two different methodologies were applied: a morphometrical approach, by recording five morphometric variables, and a biochemical technique, employing the RNA/DNA index (RDs ) and its derived index of growth performance. The morphometrical indexes did not show differences in the larval condition between both stocks. Nonetheless, the RDs index did detect differences in the nutritional condition of larvae from different stocks. The RDs index of larvae in pre-flexion and flexion stages showed significant differences between stocks, indicating that these stages are more susceptible to starvation. The results suggest that the biochemical indexes prove to be more sensitive than the morphometric indexes to detect slight differences in hake larvae nutritional condition. The scope and limitations of these techniques for the analysis of the nutritional condition of larvae are discussed.

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The presence, biosynthesis and functional role of sterols in the green microalga Haematococcus pluvialis remain poorly understood. In this work we studied the effect of high-light (HL) stress on sterol synthesis in H. pluvialis UTEX 2505 cells. HL stress induced the synthesis of sterols in parallel with that of triacylglycerides (TAG), giving rise to the synthesis of cholesterol over that of phytosterols. Blockage of the carotenogenic 1-deoxy-D-xylulose 5-phosphate (MEP) pathway is shown to be involved in HL-induced sterol synthesis. In addition, high irradiance exposure induced MEP- and fatty acid (FA)-biosynthetic transcripts. The pharmacological inhibition of these pathways suggests a possible feedback regulation of sterol and FA homeostasis. Finally, both lipid classes proved crucial to the adequate photosynthetic performance of H. pluvialis grown under HL intensity stress. Our findings reveal new insights into H. pluvialis lipid metabolism that contribute to the development of value-added bioproducts from microalgae.

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