An overview of the two-component system GarR/GarS role on antibiotic production in Streptomyces coelicolor.

The Streptomyces genus comprises Gram-positive bacteria known to produce over two-thirds of the antibiotics used in medical practice. The biosynthesis of these secondary metabolites is highly regulated and influenced by a range of nutrients present in the growth medium. In Streptomyces coelicolor, glucose inhibits the production of actinorhodin (ACT) and undecylprodigiosin (RED) by a process known as carbon catabolite repression (CCR). However, the mechanism mediated by this carbon source still needs to be understood. It has been observed that glucose alters the transcriptomic profile of this actinobacteria, modifying different transcriptional regulators, including some of the one- and two-component systems (TCSs). Under glucose repression, the expression of one of these TCSs SCO6162/SCO6163 was negatively affected. We aimed to study the role of this TCS on secondary metabolite formation to define its influence in this general regulatory process and likely establish its relationship with other transcriptional regulators affecting antibiotic biosynthesis in the Streptomyces genus. In this work, in silico predictions suggested that this TCS can regulate the production of the secondary metabolites ACT and RED by transcriptional regulation and protein-protein interactions of the transcriptional factors (TFs) with other TCSs. These predictions were supported by experimental procedures such as deletion and complementation of the TFs and qPCR experiments. Our results suggest that in the presence of glucose, the TCS SCO6162/SCO6163, named GarR/GarS, is an important negative regulator of the ACT and RED production in S. coelicolor. KEY POINTS: • GarR/GarS is a TCS with domains for signal transduction and response regulation • GarR/GarS is an essential negative regulator of the ACT and RED production • GarR/GarS putatively interacts with and regulates activators of ACT and RED.

Effects of Blood flow Restriction and Load on Mean Propulsive Velocity and Subjective Perceived Exertion During Squat and Bench Press Exercises.

BACKGROUND: The aim of this study was to determine the influence of different percentages of blood flow restriction (BFR) and loads on mean propulsive velocity (MPV) and subjective perceived exertion during squat (SQ) and bench press (BP) exercises. HYPOTHESIS: Higher percentages of BFR will positively affect dependent variables, increasing MPV and reducing perceived exertion. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: Eight healthy young male athletes took part. Two sets of 6 repetitions at 70% 1-repetition maximum (1RM), 2 sets of 4 repetitions at 80% 1RM, and 2 sets of 2 repetitions at 90% 1RM were performed randomly; 5-minute recoveries were applied in all sets. The varying arterial occlusion pressure (AOP) applied randomly was 0% (Control [CON]), 80%, and 100%. RESULTS: No statistically significant differences in MPV were found during the BP exercise at any percentage of BFR at any percentage 1RM. During the SQ exercise, MPV results showed statistically significant increases of 5.46% (P = 0.04; ηp2 = 0.31) between CON and 100% AOP at 90% 1RM. The perceived exertion results for the BP exercise showed statistically significant reductions of -8.66% (P < 0.01; ηp2 = 0.06) between CON and 100% AOP at 90% 1RM. During the SQ exercise, the perceived exertion results showed significant reductions of -10.04% (P = 0.04; ηp2 = 0.40) between CON and 100% AOP at 80% 1RM; -5.47% (P = 0.02; ηp2 = 0.48) between CON and 80% AOP at 90% 1RM; and -11.83% (P < 0.01; ηp2 = 0.66) between CON and 100% AOP at 90% 1RM. CONCLUSION: BFR percentages ~100% AOP at 90% 1RM improved acutely MPV (only in SQ exercises) and reduced acutely perceived exertion (in both exercises). These findings are important to consider when prescribing resistance training for healthy male athletes.

Black Truffle Aroma Evaluation: SPME-GC-MS vs. Sensory Experts.

Nowadays, the truffle aroma attribute is not included as a quality parameter in the current recommendation that explains the truffle quality (UNECE standard 53 FFV3) and establishes the truffle commercial categories. However, the aroma is the main reason why truffles are worldwide appreciated. Indeed, more than 30 aromatic molecules compose it, and this is the reason why the human evaluation and identification of these odorants, without previous training, is quite subjective. Analytical techniques such as gas chromatography techniques, however, can establish an aromatic profile and detect potential aromatic markers. In this study, 16 tasting experts were trained to make more objective the truffle aroma evaluation and odorants identification. For this, a comparison between solid-phase microextraction gas chromatography coupled with mass spectrometry (SPME-GC-MS) and sensory expert evaluation was carried out in six sessions during different harvesting times in the black truffle season (December, January, and February). Both techniques were able to separate truffles depending on the harvesting time. Also, a list of volatile organic compounds related to the aromatic attributes was reported. This information will help to provide a more objective T. melanosporum truffle sensory evaluation.

Transmission and dynamics of mother-infant gut viruses during pregnancy and early life.

Early development of the gut ecosystem is crucial for lifelong health. While infant gut bacterial communities have been studied extensively, the infant gut virome remains under-explored. To study the development of the infant gut virome over time and the factors that shape it, we longitudinally assess the composition of gut viruses and their bacterial hosts in 30 women during and after pregnancy and in their 32 infants during their first year of life. Using shotgun metagenomic sequencing applied to dsDNA extracted from Virus-Like Particles (VLPs) and bacteria, we generate 205 VLP metaviromes and 322 total metagenomes. With this data, we show that while the maternal gut virome composition remains stable during late pregnancy and after birth, the infant gut virome is dynamic in the first year of life. Notably, infant gut viromes contain a higher abundance of active temperate phages compared to maternal gut viromes, which decreases over the first year of life. Moreover, we show that the feeding mode and place of delivery influence the gut virome composition of infants. Lastly, we provide evidence of co-transmission of viral and bacterial strains from mothers to infants, demonstrating that infants acquire some of their virome from their mother's gut.

Choice of DNA extraction method affects stool microbiome recovery and subsequent phenotypic association analyses.

The lack of standardization in the methods of DNA extraction from fecal samples represents the major source of experimental variation in the microbiome research field. In this study, we aimed to compare the metagenomic profiles and microbiome-phenotype associations obtained by applying two commercially available DNA extraction kits: the AllPrep DNA/RNA Mini Kit (APK) and the QIAamp Fast DNA Stool Mini Kit (FSK). Using metagenomic sequencing data available from 745 paired fecal samples from two independent population cohorts, Lifelines-DEEP (LLD, n = 292) and the 500 Functional Genomics project (500FG, n = 453), we confirmed significant differences in DNA yield and the recovered microbial communities between protocols, with the APK method resulting in a higher DNA concentration and microbial diversity. Further, we observed a massive difference in bacterial relative abundances at species-level between the APK and the FSK protocols, with > 75% of species differentially abundant between protocols in both cohorts. Specifically, comparison with a standard mock community revealed that the APK method provided higher accuracy in the recovery of microbial relative abundances, with the absence of a bead-beating step in the FSK protocol causing an underrepresentation of gram-positive bacteria. This heterogeneity in the recovered microbial composition led to remarkable differences in the association with anthropometric and lifestyle phenotypes. The results of this study further reinforce that the choice of DNA extraction method impacts the metagenomic profile of human gut microbiota and highlight the importance of harmonizing protocols in microbiome studies.

Detection of echinostomatid trematode eggs at the forest-oil palm interface in Sabah, Malaysia.

In this study, we report the occurrence of echinostomatid eggs in feces of wildlife, domestic animals and humans frequenting the forest­oil palm plantation interface in the Kinabatangan (Sabah, Malaysia), and discuss potential implications for public health. Using microscopy, we detected echinostomatid eggs in six host species, including Asian palm civets (Paradoxurus hermaphroditus [13/18]), leopard cats (Prionailurus bengalensis [3/4]), long-tailed macaques (Macaca fascicularis [1/10]), domestic dogs [3/5] and cats [1/1], and humans [7/9]. Molecular analysis revealed a close genetic proximity of civet echinostomatids to Artyfechinostomum malayanum, a zoonotic parasite of public health relevance. The intermediate hosts for A. malayanum have been reported in at least 3 districts in Sabah, suggesting that all the necessary elements required for the completion of the parasite's life cycle are present. Our findings point at the presence of zoonotic trematodes in an area with high human­wildlife interaction and highlight the potential public and animal health concern of zoonotic trematode infection in the context of Southeast Asia's rapidly changing ecosystems.

Host genetic regulation of human gut microbial structural variation.

Although the impact of host genetics on gut microbial diversity and the abundance of specific taxa is well established1-6, little is known about how host genetics regulates the genetic diversity of gut microorganisms. Here we conducted a meta-analysis of associations between human genetic variation and gut microbial structural variation in 9,015 individuals from four Dutch cohorts. Strikingly, the presence rate of a structural variation segment in Faecalibacterium prausnitzii that harbours an N-acetylgalactosamine (GalNAc) utilization gene cluster is higher in individuals who secrete the type A oligosaccharide antigen terminating in GalNAc, a feature that is jointly determined by human ABO and FUT2 genotypes, and we could replicate this association in a Tanzanian cohort. In vitro experiments demonstrated that GalNAc can be used as the sole carbohydrate source for F. prausnitzii strains that carry the GalNAc-metabolizing pathway. Further in silico and in vitro studies demonstrated that other ABO-associated species can also utilize GalNAc, particularly Collinsella aerofaciens. The GalNAc utilization genes are also associated with the host's cardiometabolic health, particularly in individuals with mucosal A-antigen. Together, the findings of our study demonstrate that genetic associations across the human genome and bacterial metagenome can provide functional insights into the reciprocal host-microbiome relationship.

Draft genome sequences of four Morganella morganii strains isolated from Colombian colorectal cancer patient stool specimens.

We report the draft genome sequences of four Morganella morganii strains isolated from the stools of four patients diagnosed with colorectal cancer (CRC) in Medellín, Colombia. These genomes represent an important addition to the limited number of genomes of M. morganii strains originating from CRC patients currently available.

Multiomics analysis reveals B. MO1 as a distinct Babesia species and provides insights into its evolution and virulence.

Babesiosis, caused by protozoan parasites of the genus Babesia , is an emerging tick-borne disease of significance for both human and animal health. Babesia parasites infect erythrocytes of vertebrate hosts where they develop and multiply rapidly to cause the pathological symptoms associated with the disease. The identification of various Babesia species underscores the ongoing risk of new zoonotic pathogens capable of infecting humans, a concern amplified by anthropogenic activities and environmental shifts impacting the distribution and transmission dynamics of parasites, their vectors, and reservoir hosts. One such species, Babesia MO1, previously implicated in severe cases of human babesiosis in the midwestern United States, was initially considered closely related to B. divergens , the predominant agent of human babesiosis in Europe. Yet, uncertainties persist regarding whether these pathogens represent distinct variants of the same species or are entirely separate species. We show that although both B. MO1 and B. divergens share similar genome sizes, comprising three nuclear chromosomes, one linear mitochondrial chromosome, and one circular apicoplast chromosome, major differences exist in terms of genomic sequence divergence, gene functions, transcription profiles, replication rates and susceptibility to antiparasitic drugs. Furthermore, both pathogens have evolved distinct classes of multigene families, crucial for their pathogenicity and adaptation to specific mammalian hosts. Leveraging genomic information for B. MO1, B. divergens , and other members of the Babesiidae family within Apicomplexa provides valuable insights into the evolution, diversity, and virulence of these parasites. This knowledge serves as a critical tool in preemptively addressing the emergence and rapid transmission of more virulent strains.

PICALO: principal interaction component analysis for the identification of discrete technical, cell-type, and environmental factors that mediate eQTLs.

Expression quantitative trait loci (eQTL) offer insights into the regulatory mechanisms of trait-associated variants, but their effects often rely on contexts that are unknown or unmeasured. We introduce PICALO, a method for hidden variable inference of eQTL contexts. PICALO identifies and disentangles technical from biological context in heterogeneous blood and brain bulk eQTL datasets. These contexts are biologically informative and reproducible, outperforming cell counts or expression-based principal components. Furthermore, we show that RNA quality and cell type proportions interact with thousands of eQTLs. Knowledge of hidden eQTL contexts may aid in the inference of functional mechanisms underlying disease variants.

Spanish Cross-Cultural Adaptation and Validation of the Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow Score.

CONTEXT: There are no available questionnaires in Spanish that assess the function and performance of shoulder and elbow in overhead sports. The Kerlan-Jobe Orthopaedic Clinic (KJOC) score is a reference tool for this purpose. We aimed to cross-culturally adapt and investigate its measurement properties in Spanish overhead athletes. DESIGN: Cross-cultural adaptation followed the steps of direct translation, back translation, comprehensibility analysis, and review by the Committee of Experts. Then, symptomatic and asymptomatic overhead athletes were invited to complete an electronic version of the Spanish adaptation (KJOC-Sp). The structural validity was evaluated through an exploratory factor analysis with principal axis factoring. Hypotheses were tested for known-groups and convergent validity, studying the correlation with the Shoulder Pain and Disability Index and the Disabilities of the Arm, Shoulder, and Hand Sports Module questionnaires in symptomatic athletes. Cronbach alpha was calculated for internal consistency and intraclass correlation coefficient (ICC)2,1 for test-retest reliability. Floor and ceiling effects and time to completion were also calculated. RESULTS: The KJOC-Sp maintained the content of the original version and was adapted to the new population. One hundred participants (41 females and 59 males) with a mean age of 22.4 (5.9) years participated in the study of measurement properties. The factor analysis revealed a 1-factor solution. Symptomatic participants scored significantly lower than asymptomatic, with a large effect size (P < .001; r = .67). Correlations were of -.60 (P < .05) with the Shoulder and Pain Disability Index questionnaire and -0.66 (P < .05) with the Disabilities of the Arm, Shoulder, and Hand Sports Module questionnaire. Cronbach alpha was .98 (95% confidence interval, .97-.98) and the ICC2,1 was .96 (95% confidence interval .93-.98). No floor or ceiling effects were observed among the symptomatic athletes, while mean time to completion was 121 seconds. CONCLUSION: The KJOC-Sp is equivalent to the original score, aside from valid and reliable, without floor or ceiling effects in symptomatic athletes and with a low time consumption.

Influence of a football match on landing biomechanics and jump performance in female football players.

This study aimed to assess the acute effect of a competitive football match on jump performance and kinematic parameters during jump landing in semiprofessional female football players. Twenty-two semiprofessional players (20 ± 3 years) underwent a drop jump task for a posterior video analysis of the landing phase. These measurements were obtained at (1) baseline, (2) after, and (3) 48 h after a competitive football match. A one-way ANOVA with repeated measures was employed to detect differences over the time. There was a main effect of time for maximal knee flexion angle during drop landing (p = 0.001). In comparison with baseline, maximal knee flexion angle was reduced immediately post-match and was still reduced 48 h after the match (63.4 ± 8.6 vs 57.0 ± 11.7 vs 48.9 ± 19.1, p ≤ 0.038). There was also a main effect of time for drop jump height (p < 0.001). Drop jump height was reduced immediately post-match and remained low 48 h after the match in comparison with baseline (27.3 ± 3.6 vs 24.5 ± 2.8 ~ 25.5 ± 3.0 cm, p ≤ 0.002). There was a main effect of time on hip flexion angle during landing (p = 0.001), but the pairwise comparison revealed that this variable was not affected immediately post-match but was lower 48 h after the match than at baseline (50.1 ± 10.1 ~ 50.8 ± 13.2 vs 38.1 ± 17.8 °, p ≤ 0.005). A competitive football match worsened jump performance and several landing biomechanical parameters in female football players, which were still decreased in comparison with baseline even 48 h after the match.

The gut microbiome across the cardiovascular risk spectrum.

AIMS: Despite treatment advancements, cardiovascular disease remains a leading cause of death worldwide. Identifying new targets is crucial for enhancing preventive and therapeutic strategies. The gut microbiome has been associated with coronary artery disease (CAD), however our understanding of specific changes during CAD development remains limited. We aimed to investigate microbiome changes in participants without clinically manifest CAD with different cardiovascular risk levels and in patients with ST-elevation myocardial infarction (STEMI). METHODS: In this cross-sectional study, we characterized the gut microbiome using metagenomics of 411 faecal samples from individuals with low (n=130), intermediate (n=130) and high (n=125) cardiovascular risk based on the Framingham score, and STEMI patients (n=26). We analysed diversity, and differential abundance of species and functional pathways while accounting for confounders including medication and technical covariates. RESULTS: Collinsella stercoris, Flavonifractor plautii and Ruthenibacterium lactatiformans showed increased abundances with cardiovascular risk, while Streptococcus thermophilus was negatively associated. Differential abundance analysis revealed eight species and 49 predicted metabolic pathways that were differently abundant among the groups. In the gut microbiome of STEMI patients, there was a depletion of pathways linked to vitamin, lipid and amino-acid biosynthesis. CONCLUSION: We identified four microbial species showing a gradual trend in abundance from low-risk individuals to those with STEMI, and observed differential abundant species and pathways in STEMI patients compared to those without clinically manifest CAD. Further investigation is warranted to gain deeper understanding of their precise role in CAD progression and potential implications, with the ultimate goal of identifying novel therapeutic targets.

Despite previous studies demonstrating dysbiosis in STEMI patients, our understanding of the precise microbiome changes across the cardiovascular risk spectrum remains limited. This study addresses this knowledge gap by providing insights into the gut microbiome composition of individuals across varying cardiovascular risk levels and STEMI patients. By examining the gut microbiome of carefully selected participants from the general population with three different risk levels and a unique group of STEMI patients, we identified microbial species and pathways with differential abundance across the groups. Several of these species and pathways are associated with inflammation and lipid metabolism, which are key factors in CAD development. Collinsella stercoris, Flavonifractor plautii and Ruthenibacterium lactatiformans are increasingly abundant, while Streptococcus thermophilus is decreasingly abundant across the cardiovascular risk spectrum. The gut microbiome of STEMI patients showed eight differentially abundant species compared to groups at risk. Notably, four of these species, characterized by an elevated abundance in STEMI patients, have not been previously reported.

From Multi- to Single-Hollow Trimetallic Nanocrystals by Ultrafast Heating.

Metal nanocrystals (NCs) display unique physicochemical features that are highly dependent on nanoparticle dimensions, anisotropy, structure, and composition. The development of synthesis methodologies that allow us to tune such parameters finely emerges as crucial for the application of metal NCs in catalysis, optical materials, or biomedicine. Here, we describe a synthetic methodology to fabricate hollow multimetallic heterostructures using a combination of seed-mediated growth routes and femtosecond-pulsed laser irradiation. The envisaged methodology relies on the coreduction of Ag and Pd ions on gold nanorods (Au NRs) to form Au@PdAg core-shell nanostructures containing small cavities at the Au-PdAg interface. The excitation of Au@PdAg NRs with low fluence femtosecond pulses was employed to induce the coalescence and growth of large cavities, forming multihollow anisotropic Au@PdAg nanostructures. Moreover, single-hollow alloy AuPdAg could be achieved in high yield by increasing the irradiation energy. Advanced electron microscopy techniques, energy-dispersive X-ray spectroscopy (EDX) tomography, X-ray absorption near-edge structure (XANES) spectroscopy, and finite differences in the time domain (FDTD) simulations allowed us to characterize the morphology, structure, and elemental distribution of the irradiated NCs in detail. The ability of the reported synthesis route to fabricate multimetallic NCs with unprecedented hollow nanostructures offers attractive prospects for the fabrication of tailored high-entropy alloy nanoparticles.

Effect of energy level of photobiomodulation therapy on bone repair in rats / Efecto del nivel de energía de la terapia de fotobiomodulación sobre la reparación ósea en ratas

Abstract The aim of this experimental study was to determine the effect of photobiomodulation therapy on bone repair in a rat tibia osteotomy model at 15 and 30 days. The sample consisted of 36 male Holtzman rats that were randomized into 6 equal groups. Groups A1 and A2: osteotomy + 1 J laser energy. Groups B1 and B2: osteotomy + 3 J laser energy. Groups C1 and C2 (controls): osteotomy only. The bone repair was analyzed by histological evaluation of osteoblasts and osteocytes both at 15 days (groups A1, B1, and C1) and at 30 days (groups A2, B2, and C2). Within the results, in all groups a greater number of osteoblasts was found at 15 days vs 30 days (p<0.05), and a greater number of osteocytes in B1 and C2 vs B2 and C1, respectively (p<0.05). When evaluating the 3 groups worked up to 15 days, more osteoblasts were found in A1 and C1 vs B1 (p<0.001); and osteocytes predominated in A1 and B1 vs C1 (p<0.001). At 30 days there was a greater quantity of osteoblasts in C2 vs A2 and B2 (p<0.05) and of osteocytes in C2 vs B2 (p<0.05). It is concluded that 1 J photobiomodulation therapy improved bone repair at 15 days; however, this improvement was not observed at 30 days because there were no differences between the irradiated groups and the control.

Resumen El objetivo de este estudio experimental fue determinar el efecto de terapia de fotobiomodulación sobre la reparación ósea en un modelo de osteotomía de tibia de rata a los 15 y 30 días. La muestra estuvo compuesta por 36 ratas Holtzman macho que se aleatorizaron en 6 grupos iguales. Grupos A1 y A2: osteotomía + energía láser de 1 Joule. Grupos B1 y B2: osteotomía + energía láser 3 Joule. Grupos C1 y C2 (controles): solo osteotomía. La reparación ósea fue analizada por evaluación histológica de osteoblastos y osteocitos tanto a los 15 días (grupos A1, B1 y C1) como a los 30 días (grupos A2, B2 y C2). Como resultados se encontró que en todos los grupos hubo mayor número de osteoblastos a los 15 días vs. 30 días (p<0,05), y mayor número de osteocitos en B1 y C2 vs B2 y C1, respectivamente (p<0,05). Al evaluar a los animales a los 15 días, se observó mayor número de osteoblastos en A1 y C1 vs B1 (p<0.001); y mayor número de osteocitos en A1 y B1 vs C1 (p<0,001). Al evaluar a los ratones a los 30 días hubo mayor cantidad de osteoblastos en C2 vs A2 y B2 (p<0,05) y de osteocitos en C2 vs B2 (p<0,05). Se concluye que la terapia de fotobiomodulación con 1 Joule mejoró la reparación ósea a los 15 días; sin embargo, dicha mejora no se observó a los 30 días porque no hubo diferencias entre los grupos irradiados y el control.

The untapped potential of actinobacterial lanthipeptides as therapeutic agents.

The increase in bacterial resistance generated by the indiscriminate use of antibiotics in medical practice set new challenges for discovering bioactive natural products as alternatives for therapeutics. Lanthipeptides are an attractive natural product group that has been only partially explored and shows engaging biological activities. These molecules are small peptides with potential application as therapeutic agents. Some members show antibiotic activity against problematic drug-resistant pathogens and against a wide variety of viruses. Nevertheless, their biological activities are not restricted to antimicrobials, as their contribution to the treatment of cystic fibrosis, cancer, pain symptoms, control of inflammation, and blood pressure has been demonstrated. The study of biosynthetic gene clusters through genome mining has contributed to accelerating the discovery, enlargement, and diversification of this group of natural products. In this review, we provide insight into the recent advances in the development and research of actinobacterial lanthipeptides that hold great potential as therapeutics.

Wild Ungulates Constitute the Basis of the Diet of the Iberian Wolf in a Recently Recolonized Area: Wild Boar and Roe Deer as Key Species for Its Conservation.

The Iberian wolf (Canis lupus signatus) is recolonizing historical distribution areas after decades of absence. As in other human-dominated landscapes, finding a balance to protect this species by favoring recolonization and mitigating human-wildlife conflicts is a challenge. Since wolves are often generalist opportunistic predators, we studied their diet composition in central Spain to evaluate the consumption of domestic ungulates and provide reliable data that could help local authorities to deal with the current wolf-cattle ranchers conflict and coexistence. Diet composition (% prey occurrence, % prey ingested biomass) was analyzed through the identification of prey hairs present in 671 scats collected between 2017 and 2021. The wolves fed more on wild ungulates (82% occurrence) than domestic ones (18%). Wild boar (Sus scrofa, 44% occurrence) and roe deer (Capreolus capreolus, 35%) were the most consumed prey. The wolves positively selected these two species. The wolves' diets varied between seasons, years, and forest regions, but a diet based on wild ungulates predominated over domestic ones. Food niche breadth showed variations depending on seasons and years. Preserving the availability and diversity of wild ungulates may favor reducing livestock attacks and would be an achievable goal that would help to conserve this species and reduce conservation conflicts.

Sequential application of inoculation methods improves mycorrhization of Quercus ilex seedlings by Tuber melanosporum.

The use of mycorrhized seedlings has been critical to the success of modern truffle cultivation, which nowadays supplies most European black truffles (Tuber melanosporum) to markets. Ascospore inoculation has been traditionally used to produce these seedlings, but little scientific information is publicly available on the inoculation methods applied or on the possibility of combining them. We evaluated the potential of sequential inoculation for the controlled colonization of holm oak fine roots by T. melanosporum, with two different nursery assays and a full factorial design. Three inoculation methods were sequentially applied: radicle inoculation, inoculation of the substrate in seedling trays and inoculation of the substrate in the final pot. Despite the differences in the results of the two assays, which suggest that cultivation conditions and/or the timing of nursery operations may influence the relative effectiveness of inoculation methods, the sequential application appeared as an effective and realistic alternative for commercial inoculation of holm oak seedlings with T. melanosporum. The increase in the amount of inoculum applied with each inoculation method improved the mycorrhizal colonization of seedlings, whereas separately none of the inoculation methods appeared clearly superior to the other ones. The depth distribution of truffle mycorrhizae pointed that the inoculation in the final pot was more effective than other methods in lower parts of the root system, whereas the early inoculation appeared more effective to reduce the occurrence of the opportunist ectomycorrhizal fungus Sphaerosporella brunnea.

Selective enrichment of founding reproductive microbiomes allows extensive vertical transmission in a fungus-farming termite.

Mutualistic coevolution can be mediated by vertical transmission of symbionts between host generations. Termites host complex gut bacterial communities with evolutionary histories indicative of mixed-mode transmission. Here, we document that vertical transmission of gut bacterial strains is congruent across parent to offspring colonies in four pedigrees of the fungus-farming termite Macrotermes natalensis. We show that 44% of the offspring colony microbiome, including more than 80 bacterial genera and pedigree-specific strains, are consistently inherited. We go on to demonstrate that this is achieved because colony-founding reproductives are selectively enriched with a set of non-random, environmentally sensitive and termite-specific gut microbes from their colonies of origin. These symbionts transfer to offspring colony workers with high fidelity, after which priority effects appear to influence the composition of the establishing microbiome. Termite reproductives thus secure transmission of complex communities of specific, co-evolved microbes that are critical to their offspring colonies. Extensive yet imperfect inheritance implies that the maturing colony benefits from acquiring environmental microbes to complement combinations of termite, fungus and vertically transmitted microbes; a mode of transmission that is emerging as a prevailing strategy for hosts to assemble complex adaptive microbiomes.

Aromatic profile of black truffle grown in Argentina: Characterization of commercial categories and alterations associated to maturation, harvesting date and orchard management practices.

Black truffle (Tuber melanosporum) is one of the most appreciated fungi in the world mainly due to its aromatic properties. In the emerging markets such as Argentina, the aroma of locally produced truffles has not been described yet. The volatile organic compounds (VOCs) from 102 black truffles from Argentina were analyzed using solid phase microextraction gas chromatography coupled with mass spectrometer detector (SPME-GC-MS). Several factors such as commercial category, maturity stage, host tree, geographical origin, and aromatic defects detected during classification were also registered and considered. As a result, 79 VOCs were detected, among which 2-methyl-propanal, 2-butanone, 2-methyl-1-propanol, butanal-3-methyl, 3-methyl-1-butanol, 2-methyl-1-butanol were present in high percentage in fresh mature truffles, whereas immature truffles were associated with 3,5-dimethoxytoluene, 2-phenyl-2-butenal, 2,3-dimethoxytoluene. The Argentine black truffles showed significant similarities in their aromatic profile when compared with their Australian and European counterparts, but with some distinctive notes.