Fecal Metabolome and Bacterial Composition in Severe Obesity:Impact of Diet and Bariatric Surgery

The aim of this study was to monitor the impact of a preoperative low-calorie diet and bariatric surgery on the bacterial gut microbiota composition and functionality in severe obesity and to compare sleeve gastrectomy (SG) versus Roux-en-Y gastric bypass (RYGB). The study also aimed to incorporate big data analysis for the omics results and machine learning by a Lasso-based analysis to detect the potential markers for excess weight loss. Forty patients who underwent bariatric surgery were recruited (14 underwent SG, and 26 underwent RYGB). Each participant contributed 4 fecal samples (baseline, post-diet, 1 month after surgery and 3 months after surgery). The bacterial composition was determined by 16S rDNA massive sequencing using MiSeq (Illumina). Metabolic signatures associated to fecal concentrations of short-chain fatty acids, amino acids, biogenic amines, gamma-aminobutyric acid and ammonium were determined by gas and liquid chromatography. Orange 3 software was employed to correlate the variables, and a Lasso analysis was employed to predict the weight loss at the baseline samples. A correlation between Bacillota (formerly Firmicutes) abundance and excess weight was observed only for the highest body mass indexes. The low-calorie diet had little impact on composition and targeted metabolic activity. RYGB had a deeper impact on bacterial composition and putrefactive metabolism than SG, although the excess weight loss was comparable in the two groups. Significantly higher ammonium concentrations were detected in the feces of the RYGB group. We detected individual signatures of composition and functionality, rather than a gut microbiota characteristic of severe obesity, with opposing tendencies for almost all measured variables in the two surgical approaches. The gut microbiota of the baseline samples was not useful for predicting excess weight loss after the bariatric process

Close and distant : contrasting the metabolism of two closely related subspecies of Scots pine under the effects of folivory and summer drought

Metabolomes, as chemical phenotypes of organisms, are likely not only shaped by the environment but also by common ancestry. If this is the case, we expect that closely related species of pines will tend to reach similar metabolomic solutions to the same environmental stressors. We examined the metabolomes of two sympatric subspecies of Pinus sylvestris in Sierra Nevada (southern Iberian Peninsula), in summer and winter and exposed to folivory by the pine processionary moth. The overall metabolomes differed between the subspecies but both tended to respond more similarly to folivory. The metabolomes of the subspecies were more dissimilar in summer than in winter, and iberica trees had higher concentrations of metabolites directly related to drought stress. Our results are consistent with the notion that certain plant metabolic responses associated with folivory have been phylogenetically conserved. The larger divergence between subspecies metabolomes in summer is likely due to the warmer and drier conditions that the northern iberica subspecies experience in Sierra Nevada. Our results provide crucial insights into how iberica populations would respond to the predicted conditions of climate change under an increased defoliation in the Mediterranean Basin

A body weight loss- and health-promoting gut microbiota is established after bariatric surgery in individuals with severe obesity

Obesity has reached an epidemic level worldwide, and bariatric surgery (BS) has been proven to be the most efficient therapy to reduce severe obesity-related comorbidities. Given that the gut microbiota plays a causal role in obesity development and that surgery may alter the gut environment, investigating the impact of BS on the microbiota in the context of severe obesity is important. Although, alterations at the level of total gut bacteria, total gene content and total metabolite content have started to be disentangled, a clear deficit exists regarding the analysis of the active fraction of the microbiota, which is the fraction that is most reactive to the BS. Here, active gut microbiota and associated metabolic functions were evaluated using shotgun proteomics and metabolomics in 40 severely obese volunteers. Samples from each volunteer were obtained under basal conditions, after a short high protein and calorie-restricted diet, and 1 and 3 months after BS, including laparoscopic surgery through Roux-en-Y Gastric Bypass or Sleeve Gastrectomy. The results revealed for the first time the most active microbes and metabolic flux distribution pre- and post-surgery and deciphered main differences in the way sugars and short-fatty acids are metabolized, demonstrating that less energy-generating and anaerobic metabolism and detoxification mechanisms are promoted post-surgery. A comparison with non-obese proteome data further signified different ways to metabolize sugars and produce short chain fatty acids and deficiencies in proteins involved in iron transport and metabolism in severely obese individuals compared to lean individuals.This work was funded by grants SAF2015-65878-R, BIO2017-85522-R, PID2019-105969GB-I00 and RTI2018-095166-B-I00 from the Ministry of Science, Innovation and Universities, by the Ministry of Science and Innovation, by the Instituto de Salud Carlos III (projects PIE14/00045 and AC17/00022), Fundación Agencia Española contra el Cáncer and Instituto de Salud Carlos III(projects ERA NET TRANSCAN-2 AC17/00022 and AECC 2017-1485), Generalitat Valenciana (project Prometeo/2018/A/133) and co-financed by the European Regional Development Fund (ERDF). The proteomic analysis was performed in the Proteomics Facility of The Spanish National Center for Biotechnology (CNB-CSIC) that belongs to ProteoRed, PRB3-ISCIII, supported by grant PT17/0019.Peer reviewe

De semilla a plántula: Explorando los estadios iniciales del ciclo de vida en coníferas exóticas

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Invasiones biológicas: el caso de las coníferas exóticas.

El género Linum L. ha jugado un papel importante en la economía y desarrollo social desde hace miles de años. Además, ha sido históricamente importante para el estudio de la heterostilia, desde el punto de vista de la investigación evolutiva. La heterostilia es un mecanismo que promueve la fecundación cruzada, al mismo tiempo que evita la interferencia entre órganos femeninos y masculinos de las flores. Sin embargo, sólo recientemente se ha empezado a usar este género para reconstruir las transiciones evolutivas que han conducido a la construcción de la heterostilia o a su pérdida. Ello pasa por disponer primero de una reconstrucción de la relaciones filogenéticas entre las especies. En el artículo se muestra una revisión de las características fundamentales del género Linum, como representante de la heterostilia en el mediterráneo y del proyecto de investigación que está desarrollándose actualmente cuyo objetivo es dar un primer paso hacia un enfoque macro (a nivel de todo el género) y micro evolutivo (dentro de especies agregadas, muy próximas entre sí, sin determinación taxonómica clara) y esclarecer las relaciones filogenéticas del género Linum, para poder así estudiar cómo ha acontecido la aparición de la heterostilia, cuál fue el estado ancestral y cómo ha evolucionado el polimorfismo floral

Little evidence of invasion by alien conifers in Europe

Aim Conifers are invasive species in many parts of the world, especially in the Southern Hemisphere. There are many introduced conifers in Europe, but their status as alien species is poorly documented. We conducted a comprehensive literature review to ascertain the extent to which alien conifers can be considered invasive. Location Europe. Methods We reviewed the historical record of alien conifer invasion in Europe (i.e. species with a native range outside the continental boundaries of Europe) by screening the DAISIE database and the ISI Web of Science. Results According to DAISIE, there are 54 alien conifer species in Europe. Pseudotsuga menziesii is the species recorded as naturalized in the most countries (12) and the UK is the country with the most naturalized species (18). Thirty-seven of these conifers have been studied, to some extent, in a total of 131 papers (212 records). Nevertheless, only a few papers have investigated aspects related to biological invasions. In fact, the species are not referred to as alien by the authors in more than half of the papers (66%). Twenty-five per cent of the papers have investigated plant traits, 46% are about biotic and abiotic factors influencing tree performance and 29% deal with ecological and economic impacts. Most papers are related to entomology, dealing with natural enemies affecting the alien conifers. Main conclusions Scientists have not yet perceived alien conifers in Europe as problematic species. Moreover, the low introduction effort, long lag-time since plantation and phylogenetic closeness between alien and native conifers are possible reasons for their low expansion in Europe to date. From a management point of view, careful observations of sites with alien conifers is necessary to watch for new invasions. From a scientific perspective, thorough analyses of the extent that introduction, rates of naturalization and biogeographical differences influence invasive spread between the two hemispheres will prove timely.Peer reviewe

Comparing seed removal of 16 pine species differing in invasiveness

Small seed mass is regarded as a robust trait related to invasion success, especially in pines. However, few studies have explored whether inva- siveness related to small seed mass is also associated to low levels of seed predation in the recipient commu- nity. We conducted field cafeteria seed removal experiments comparing 16 Pinus species that differ in seed mass to test if seed removal might impose biotic resistance to Pinus spp. and if there are differences between species related to seed mass. Seeds were removed rapidly and in high proportion. In the Mediterranean shrublands, where the experiments were conducted, rodents and ants were the main seed removers. Mean seed survival time was significantly different between species. However, smaller seeds were not the most predated. Our study suggests that, in pine species with high invasiveness, the potential higher seed removal of small seeds can be counterbal- anced by larger seed cropsPeer reviewe

Establishment constraints of an alien and a native conifer in different habitats

Alien plants are subjected to different biotic and environmental barriers that limit their establishment success in the introduced range. Pseud- otsuga menziesii (Douglas fir), a native conifer from Northwest America, is considered one of the most invasive forestry conifers in Europe. However, little is known about the ecological filters that constrain plant establishment at early life-cycle stages and differences in habitat invasibility to this species. We conducted field experiments to compare the establishment potential (i.e. post-dispersal seed removal, seed ger- mination, seedling survival and growth) of Douglas fir in beech forests, holm-oak forests and heathlands; and compared it with the taxonomically close native conifer Abies alba (Silver fir). Douglas fir seeds were more removed than Silver fir in holm-oak and in heathlands. In all habitats, seed germination was significantly higher for Douglas fir compared to that of Silver fir and, seedling mortality was extremely high in both species due to soil disturbance by wild boars and drought stress. Douglas fir mortality was only lower than Silver fir in beech forests. However, species did not differ in seedling growth. Overall, the probability of invasion success of Douglas fir decreased along the sequential stages of plant estab- lishment in all habitats. Only high seed germination rates of Douglas fir would predict its high invasive capacity but these advantages are counterbalanced by high seedling mortality. Results showed a mismatch between invasibility and current pattern of Douglas fir invasion in the study area. Therefore, future research focused on seed production and on different compo- nents of biotic resistance is recommended to eluci- date which processes are favoring its establishment success.Peer reviewe

Inducibility of chemical defences by two chewing insect herbivores in pine trees is specific to targeted plant tissue, particular herbivore and defensive trait

There is increasing evidence that plants can react to biotic aggressions with highly specific responses. However, few studies have attempted to jointly investigate whether the induction of plant defences is specific to a targeted plant tissue, plant species, herbivore identity, and defensive trait. Here we studied those factors contributing to the specificity of induced defensive responses in two economically impor- tant pine species against two chewing insect pest herbivores. Juvenile trees of Pinus pinaster andP. radiata were exposed to herbivory by two major pest threats, the large pine weevil Hylobius abietis (a bark-fee- der) and the pine processionary caterpillar Thaumetopoea pityocampa (a folivore). We quantified in two tissues (stem and needles) the constitutive (control plants) and herbivore-induced concentrations of total polyphenolics, volatile and non-volatile resin, as well as the profile of mono- and sesquiterpenes. Stem chewing by the pine weevil increased concentrations of non-volatile resin, volatile monoterpenes, and (marginally) polyphenolics in stem tissues. Weevil feeding also increased the concentration of non-vol- atile resin and decreased polyphenolics in the needle tissues. Folivory by the caterpillar had no major effects on needle defensive chemistry, but a strong increase in the concentration of polyphenolics in the stem. Interestingly, we found similar patterns for all these above-reported effects in both pine spe- cies. These results offer convincing evidence that induced defences are highly specific and may vary depending on the targeted plant tissue, the insect herbivore causing the damage and the considered defensive compound.Peer reviewe