Biology subjects

Diaz, P.

Publications and source records attributed to Diaz, P..

4 recordsLinked to original sources

bioRxiv2026

Global biogeography of mangrove sediment microbiomes is structured by a conserved core and environmental selection

Mangrove sediments are globally important biogeochemical hotspots, yet the large-scale organization and assembly of their microbiomes remain poorly resolved. Here, we compiled and analysed 390 shotgun metagenomes from mangrove sediments across 43 sites worldwide to quantify how diversity, spatial turnover, and ecological processes structure microbial communities across environmental and geographic gradients. We identify a striking dual architecture in mangrove sediment microbiomes. A remarkably small and ubiquitous taxonomic core, representing a minor fraction of total richness but dominating community abundance, persists across continents, climatic regimes, and marine realms. This core is composed primarily of anaerobic microbial lineages associated with carbon, nitrogen, and sulfur cycling and shows limited spatial and environmental turnover. In contrast, the non-core fraction is highly diverse, responds strongly to climatic and edaphic gradients, and drives most biogeographic differentiation. Assembly-process modelling reveals that deterministic selection dominates global taxonomic turnover, with homogeneous selection stabilizing shared community components and heterogeneous selection promoting regional differentiation, while dispersal limitation plays a secondary role. Network analyses further show that core taxa occupy structurally central positions in microbial co-occurrence networks, supporting overall connectivity despite pronounced regional variation in peripheral community composition. Together, these results demonstrate that mangrove sediment microbiomes combine a conserved functional backbone with an environmentally responsive periphery. This organization reconciles global functional continuity with strong regional differentiation and provides a basis for anticipating microbiome responses to environmental change in mangrove ecosystems.

ecology↗

bioRxiv2023

HIV Infection impairs the Host Response to Mycobacterium tuberculosis Infection by altering Surfactant Protein D function in the Human Lung Alveolar Mucosa

Tuberculosis is the leading cause of death for people living with HIV (PLWH). We hypothesized that altered functions of innate immune components in the human alveolar lining fluid of PLWH (HIV-ALF), drive susceptibility to Mycobacterium tuberculosis (M.tb) infection. Our results indicate a significant increase in oxidation of innate proteins and chemokine levels, and significantly lower levels and function of complement components and Th1/Th2/Th17 cytokines in HIV-ALF vs. control-ALF (non-HIV infected people). We further found a deficiency of surfactant protein-D (SP-D) and reduced binding of SP-D to M.tb that had been exposed to HIV-ALF. Primary human macrophages infected with M.tb exposed to HIV-ALF were significantly less capable of controlling the infection, which was reversed by SP-D replenishment in HIV-ALF. Thus, our data suggest that PLWH without antiretroviral therapy (ART) have declining host innate defense function in their lung mucosa, thereby favoring M.tb and potentially other pulmonary infections.

cell biology↗

bioRxiv2021

Sand dropseed (Sporobolus cryptandrus) - A new pest in Eurasian sand areas?

For the effective control of an invasive species, gathering as much information as possible on its ecology, establishment and persistence in the subjected communities is of utmost importance. We aimed to review the current distribution and characteristics of Sporobolus cryptandrus (sand dropseed), an invasive C4 grass species of North American origin recently discovered in Hungary. We aimed to provide information on (i) its current distribution paying special attention to its invasion in Eurasia; (ii) the characteristics of the invaded habitats in Central Europe; (iii) seed bank formation and germination characteristics, crucial factors in early establishment; and (iv) the effects of its increasing cover on vegetation composition. Finally, we aimed to (v) point out further research directions that could enable us to understand the invasion success of this potential invasive species. Field surveys uncovered large stands of the species in Central and Eastern Hungary with most of the locations in the former, especially the Kiskunsag region. The species invaded disturbed stands of dry and open sand grasslands, closed dune slack grasslands and it also penetrates into natural open sand grasslands from neighbouring disturbed habitats. Increasing cover of Sporobolus cryptandrus caused a decline in species richness and abundance of subordinate species both in the vegetation and seed banks, but a low density of Sporobolus cryptandrus can even have a weak positive effect on these characteristics. Viable seeds of Sporobolus were detected from all soil layers (2.5 cm layers measured from the surface to 10 cm in depth), which indicates that the species is able to form a persistent seed bank (1,114 to 3,077 seeds/m2 with increasing scores towards higher abundance of the species in vegetation). Germination of Sporobolus cryptandrus was negatively affected by both litter cover and 1 cm deep soil burial. To sum up, Sporobolus cryptandrus can be considered as a transformer invasive species, whose spread forms a high risk for dry sand and steppe grasslands in Eurasia. We can conclude that for the effective suppression of the species it is necessary: (i) to clarify the origin of the detected populations; (ii) to assess its competitive ability including its potential allelopathic effects; (iii) to assess its seed bank formation potential in habitats with different abiotic conditions; and (iv) to assess the possibility of its suppression by natural enemies and management techniques such as mowing or livestock grazing.

ecology↗

bioRxiv2019

Genomic and phylogenetic analysis of Salmonella Typhimurium and its monophasic variants responsible for invasive endemic infections in Colombia

Salmonellosis is an endemic human infection, associated with both sporadic cases and outbreaks throughout Colombia. Typhimurium is the most common Colombian serovar of Salmonella enterica, responsible for 32.5% of the Salmonella infections. Whole genome sequencing (WGS) is being used increasingly in Europe and the USA to study the epidemiology of Salmonella, but there has not yet been a WGS-based analysis of Salmonella associated with bloodstream infection in Colombia. Here, we analysed 209 genome sequences of Colombian S. Typhimurium and monophasic S. 4,[5],12:i:-isolates from Colombia from 1999 to 2017. We used a core genome-based maximum likelihood tree to define seven distinct clusters which were predominantly Sequence Type (ST) 19 isolates. We also identified the first ST313 and monophasic ST34 isolates to be reported in Colombia. The history of each cluster was reconstructed with a Bayesian tree to reveal a timeline of evolution. Cluster 7 was closely related to European multidrug-resistant (MDR) DT104. Cluster 4 became the dominant variant of Salmonella in 2016, and resistance to nalidixic acid was associated with a plasmid-encoded qnrB19 gene. Our findings suggest multiple transfers of S. Typhimurium between Europe and Colombia.\n\nAuthor summaryThe large-scale genome sequencing of Salmonella Typhimurium and monophasic Salmonella 4,[5],12:i:-involved bloodstream isolates from Colombia. The two serovars were responsible for about 1/3 of Salmonella infections in Colombia in the past 20 years. To identify the population structure we used Whole Genome Sequencing, performed in silico sequence typing, obtained phylogenetic trees, inferred the evolutionary history, detected the plasmids and prophages, and associated the antibiotic resistance (AMR) genotype with phenotype. Different clusters showed temporal replacement. The Colombian sequence type 313 was distinct from African lineages due to the absence of a key virulence-related gene, bstA. One of the Colombian clusters is likely to belong to the global epidemic of DT104, according to the evolutionary history and the AMR profile. The most common cluster in recent years was resistant to nalidixic acid and carried a plasmid-mediated antibiotic resistant gene qnrB19. Our findings will inform the ongoing efforts to combat Salmonellosis by Colombian public health departments.

genomics↗