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Biology subjects

Santos, M. P.

Publications and source records attributed to Santos, M. P..

5 recordsLinked to original sources

Distribution, ecology, and natural history of the recently rediscovered and critically endangered Santa Marta Sabrewing

The Santa Marta Sabrewing is a critically endangered (CR) hummingbird endemic to the Sierra Nevada de Santa Marta, Colombia. Prior to 2022, there were only three documented sightings of the sabrewing since it was described in 1879, including only one record between 1946 and 2022. As a result, this "lost" species has long been one of the most poorly-known birds in Colombia. We located a resident population of Santa Marta Sabrewing along the Guatapuri River near the Chemesquemena and Guatapuri villages in July 2022, and at its type locality, San Jose, in January 2023. Based on historical data and newly-collected field observations, we assess the species status and describe aspects of its natural history and ecology. Our review indicates the species has been frequently misidentified in the past, and that to date, documented evidence of its presence is limited to five localities, almost all of them restricted to the south-eastern slope of the Sierra Nevada de Santa Marta, along the mid Guatapuri river basin. Consequently, this bird appears to represent a case of microendemism. Following IUCN criteria, our data suggest that Santa Marta Sabrewing should remain listed as CR. Field observations indicate that the species is highly associated with watercourses, where males hold year-round territories and form leks. We obtained records of males in mid-elevation habitats (1,150-1,850 m) for 16 consecutive months between July 2022 and October 2023, suggesting that the species might not be an elevational migrant, as previously speculated. More information is needed to understand the species ecology so that effective conservation actions can be designed in collaboration with the indigenous communities with which the species coexists.

ecology↗

Diatom Modulation of Microbial Consortia Through Use of Two Unique Secondary Metabolites

Unicellular eukaryotic phytoplankton, such as diatoms, rely on microbial communities for survival despite lacking specialized compartments to house microbiomes (e.g., animal gut). Microbial communities have been widely shown to benefit from diatom excretions that accumulate within the microenvironment surrounding phytoplankton cells, known as the phycosphere. However, mechanisms that enable diatoms and other unicellular eukaryotes to nurture specific microbiomes by fostering beneficial bacteria and repelling harmful ones are mostly unknown. We hypothesized that diatom exudates may attune microbial communities and employed an integrated multi-omics approach using the ubiquitous diatom Asterionellopsis glacialis to reveal how it modulates its naturally associated bacteria. We show that A. glacialis reprograms its transcriptional and metabolic profiles in response to bacteria to secrete a suite of central metabolites and two unusual secondary metabolites, rosmarinic acid and azelaic acid. While central metabolites are utilized by potential bacterial symbionts and opportunists alike, rosmarinic acid promotes attachment of beneficial bacteria to the diatom and simultaneously suppresses the attachment of opportunists. Similarly, azelaic acid enhances growth of beneficial bacteria, while simultaneously inhibiting growth of opportunistic ones. We further show that the bacterial response to azelaic acid is widespread in the worlds oceans and taxonomically restricted to a handful of bacterial genera. Our results demonstrate the innate ability of an important unicellular eukaryotic group to modulate their microbial consortia, similar to higher eukaryotes, using unique secondary metabolites that regulate bacterial growth and behavior inversely in different bacterial populations.

microbiology↗

Ex-situ cultivation of Isoetes cangae and Isoetes serracarajensis (Isoetaceae) two endemic species from Brazilian Amazon

Isoetes L. is a genus of lycophytes widely distributed around the world that has a large number of endemic species. Here we document the first successful large scale ex-situ cultivation of the new endemic species from Brazilian Amazon quillworts Isoetes cangae and Isoetes serracarajensis. These isoetids are endemic of an iron mining site and grow on a superficial iron crust that occurs over ferriferous rocks. This study aimed to develop the cultivation methods of the threatened species I. cangae and monitoring its unique physiology. Plants from both species brought from Amazon lagoons were cultivated through a year in a low-cost system at a different site during different seasons. The survival rate of plants was higher as 98% and both species developed well under cultivation but showed different patterns during linear growth: I. cangae showed faster leaf development but was slower on sprout production than I. serracarajensis. The mechanism of leaf expansion is related to plasma membrane H+-ATPase activation, near to 2-fold higher in I. cangae. On the other hand, the effective quantum yield of photosystem II was higher in I. serracarajensis than in I. cangae. During the cultivation, new sporophytes of I. cangae were produced, confirming its reproductive status. We have also tested elevated iron levels on the growth of plants, but no interference of iron concentration was observed. The results of this work have broad applicability, assisting other low-cost cultivation studies, which are very important in ecosystem recovery of mining areas and conservation strategies.

plant biology↗

Genetic diversity by ISSR of two endemic quillworts (Isoetes L.) species from Amazon Iron Rocky Outcrops, Isoetes cangae e I. serracarajensis

Two lycophytes endemic species have been recently described at the State of Para, in the Amazon forest located in the North of Brazil. Genetic diversity and population structure of Isoetes cangae and I. serracarajensis were investigated through ISSR molecular markers. These analyses aim to establish strategies for future attempts for species conservation. From sixteen primers, 115 gel bands were identified from which 87% were polymorphic. A high level of polymorphic loci (81,74 % e 68,48 %) and a high Shannon index for intra populational genetic diversity was observed for each species (Sh=0.376 e 0.289) I. cangae and I. serracarajensis, respectively. The largest genetic diversity of both species relies in their own populations. The coefficient of genetic differentiation between population areas (GST) was higher in I. serracarajensis (0.5440) than in I. cangae (0.2250). Gene flow was high between I. cangae populations (1.7142) and very low in I. serracarajensis (0.4190). Principal Component Analysis (PCoA) showed that individual plants were allocated into species-specific and population groups. Overall, the results further show that I. serracarajensis (0.5440) and I. cangae are two species with considerable genetic variation. These results should be considered for effective conservation strategies of both species.

genetics↗

Genomic and structural features of the Yellow Fever virus from the 2016-2017 Brazilian outbreak

Brazil has been suffering a severe sylvatic epidemic of yellow fever virus (YFV) since late 2016. Analysis of full-length YFV genomes from all hosts involved in the Brazilian 2017 outbreak reveals that they belong to sub-lineage 1E within modern-lineage, but display several unique amino acid substitutions in highly conserved positions at NS3 and NS5 viral proteins. Evolutionary analyses indicate that YFV carrying that set of amino acid substitution circulates in the Southern Brazilian region for several months before being detected in December 2016. Structural and selection analyses support that some of these substitutions were under positive selection and could impact enzyme structure and function. Altogether, this evidence demonstrated that the current Brazilian YFV carries unique amino acid signatures in the non-structural proteins and support the hypothesis that those substitutions may be affecting the viral fitness and transmissibility.

microbiology↗