Biology subjects

Domingos, C.

Publications and source records attributed to Domingos, C..

4 recordsLinked to original sources

bioRxiv2025

Adaptive strategies of Caribbean sponge holobionts beyond the mesophotic zone

Marine sponges and their microbiomes function together as holobionts, playing essential roles in ecosystem dynamics and exhibiting remarkable adaptability across depth gradients. This study utilized a multi-omics approach, integrating microbiome and metabolome analyses, to investigate adaptive strategies in sponge holobionts inhabiting the mesophotic (80-125 m), upper-rariphotic (125-200 m), and lower-rariphotic (200-305 m) zones of Curacao. We hypothesized that depth-related environmental factors drive distinct adaptive strategies, similar to patterns observed in fish and coral assemblages. Results revealed major differences in holometabolomes and microbial communities between Demospongiae and Hexactinellida sponges, reflecting class-specific adaptive strategies. Notably, phospholipid homeoviscous adaptation to temperature and pressure emerged as a key mechanism in phosphorus metabolism. Adaptations in nitrogen metabolism were linked to diverse ammonia oxidizing archaea (AOA) symbionts, and dissolved organic matter cycling. Hexactinellid microbiomes exhibited intra-specific heterogeneity; however, species-specific associations with AOA symbionts such as Cenarchaeum and Nitrosopumilus were observed. Additionally, the lower-rariphotic hexactinellid holometabolomes highlighted the significance of the nested ecosystem concept through the identification of secondary metabolites produced by their associated fauna (aphrocallistins by zoanthids, and xanthurenic acid by shrimp). This study highlights the ecological significance of sponge holobionts in mesophotic and rariphotic ecosystems, revealing diverse adaptations to unique physicochemical conditions and biotic interactions.

microbiology↗

bioRxiv2024

Cerebrovascular reactivity mapping using breath-hold BOLD-fMRI: comparison of signal models combined with voxelwise lag optimization

Cerebrovascular reactivity (CVR) can be mapped noninvasively using blood oxygenation level dependent (BOLD) fMRI during a breath-hold (BH) task. Previous studies showed that the BH BOLD response is best modeled as the convolution of the partial pressure of end-tidal CO2 (PetCO2) with a canonical hemodynamic response function (HRF). However, previous model comparisons employed a global bulk time lag, which is now well accepted to provide only a rough approximation of the heterogeneous distribution of response latencies across the brain. Here, we investigate the best modeling approach for mapping CVR based on BH BOLD-fMRI data, when using a lagged general linear model approach combined with voxelwise lag optimization. In a group of fourteen healthy participants, we compared models considering: two types of regressors (PetCO2 and Block), three convolution models (no convolution; convolution with a single gamma HRF; and convolution with a double gamma HRF), and a variable HRF delay (3-11s). We found no significant improvements in model fit with other delays, and hence selected the canonical delay of 6s. Although the two regressor types yielded similar model fits, PetCO2 produced significantly greater CVR values than Block models. Interestingly, a single gamma HRF yielded the greatest CVR values in PetCO2 models, while block models benefited from convolution with a double gamma HRF. In conclusion, when modeling BH BOLD-fMRI signals with voxelwise lag optimization, PetCO2 regressors convolved with a single gamma HRF should be preferentially used. In case good quality PetCO2 recordings are unavailable, a block-based model convolved with the canonical HRF may be a good alternative. In conclusion, our manuscript reports the first systematic signal model comparison, providing evidence to support the use of specific modeling approaches for CVR mapping based on BH BOLD-fMRI.

bioengineering↗

bioRxiv2021

Dysfunction of grey matter NG2 glial cells affects neuronal plasticity and behavior

NG2 glia represent a distinct type of macroglial cells in the CNS and are unique among glia because they receive synaptic input from neurons. They are abundantly present in white and grey matter. While the majority of white matter NG2 glia differentiates into oligodendrocytes, the physiological impact of grey matter NG2 glia and their synaptic input are ill defined yet. Here we asked whether dysfunctional NG2 glia affect neuronal signaling and behavior. We generated mice with inducible deletion of the K+ channel Kir4.1 in NG2 glia and performed comparative electrophysiological, immunohistochemical, molecular and behavioral analyses. Focussing on the hippocampus, we found that loss of the Kir4.1 potentiated synaptic depolarizations of NG2 glia and enhanced the expression of myelin basic protein. Notably, while mice with targeted deletion of the K+ channel in NG2 glia showed impaired long term potentiation at CA3-CA1 synapses, they demonstrated improved spatial memory as revealed by testing new object location recognition. Our data demonstrate that proper NG2 glia function is critical for normal brain function and behavior.

neuroscience↗

bioRxiv2019

Emergence of the Zika virus Asian lineage in Angola

Research In ContextO_ST_ABSEvidence before this studyC_ST_ABSWe searched PubMed without language restrictions using the keywords Zika and Africa for papers published to October 2018. We also checked available Situation Report publications from WHO for evidence of Zika virus (ZIKV) or congenital Zika disease in Africa. ZIKV African lineage has been detected within Africa since the mid 20th century, yet evidence for spread of the ZIKV Asian lineage within Africa is limited. Two countries in Africa (Cabo Verde and Angola) have reported ZIKV cases that are believed to be caused by a newly introduced Asian lineage virus. Sequence data are critical for confirming and understanding the spread of ZIKV Asian lineage within Africa, but these data are currently limited to a single 193bp fragment of the ZIKV NS1 gene from Angola. In addition, whilst epidemiological data on ZIKV and suspected microcephaly cases have been reported in detail from Cabo Verde, data from Angola are extremely limited.\n\nAdded value of this studyWe provide a detailed report of detected ZIKV acute cases and suspected microcephaly cases in Angola. We sequence ZIKV genomes from three acutely infected cases. These represent the first three Asian lineage genomes available from Africa, one of which was acquired from a baby with confirmed microcephaly. Analysis of these sequences suggests that ZIKV may have been introduced to Angola between July 2015 and June 2016, after which it likely circulated for at least one year. This provides the first genetic confirmation of autochthonous ZIKV Asian lineage transmission within Africa. We suggest that the virus was more likely introduced to Angola directly from Brazil, rather than from Cabo Verde. Our analyses from Angola, only the second African country to report presence of the Asian virus lineage, therefore improve our understanding of the extent and clinical impact of ZIKV Asian lineage in the continent.\n\nImplications of all the available evidenceThe circulation of ZIKV Asian lineage within parts of sub-Saharan Africa is concerning given the potential for continued viral spread across much of the continent. Available evidence suggests that ZIKV has circulated and caused cases of microcephaly in Cabo Verde and in Angola. Detecting additional ZIKV transmission using only clinical data on suspected microcephaly or clusters of mild illness may be challenging in countries where systems for reporting birth defects are limited and infectious disease burden is high. Further spread of the ZIKV Asian lineage would likely not be detected unless molecular surveillance systems for ZIKV are implemented to routinely monitor ZIKV transmission in Africa. Implementation of such a surveillance system is especially important in countries that are linked by high human mobility to areas that have experienced recent or ongoing outbreaks of ZIKV.\n\nAbstractO_ST_ABSBackgroundC_ST_ABSZika virus (ZIKV) infections and suspected microcephaly cases have been recently reported in Angola, but no data are available on the origins, epidemiology, and diversity of the virus.\n\nMethodsSerum samples from 54 suspected ZIKV cases, 76 suspected microcephaly cases, and 24 mothers of infants with suspected microcephaly were received by the Angolan Ministry of Health. Computed tomographic brain imaging and serological assays (PRNT) were conducted on one microcephalic infant. All sera were tested for ZIKV by RT-qPCR. 349 samples from HIV+ patients and 336 samples from patients suspected of chikungunya virus or dengue virus infection were also tested. Portable sequencing was used to generate Angolan ZIKV genome sequences, including from a ZIKV+ neonate with microcephaly born in Portugal to an Angolan resident. Genetic and mobility data were analysed to investigate the date of introduction and geographic origin of ZIKV in Angola.\n\nFindingsFour autochthonous cases were ZIKV positive via RT-qPCR, with all positive samples collected between December 2016 and June 2017. Viral genomes were generated for two of these cases, and from the neonate with microcephaly identified in Portugal. Genetic analyses and other data indicate that ZIKV was introduced to Angola from Brazil between July 2015 and June 2016. This introduction likely initiated local ZIKV circulation in Angola that continued until June 2017. The scanned microcephaly case showed brain abnormalities consistent with congenital Zika syndrome and serological evidence for maternal ZIKV infection.\n\nInterpretationOur analyses confirm the autochthonous transmission of the ZIKV Asian lineage in continental Africa. Conducting ZIKV surveillance throughout Africa is critical in the light of presented evidence for autochthonous ZIKV transmission in Angola, and associated microcephaly cases.\n\nFundingRoyal Society, Wellcome Trust, CNPq, CAPES, ERC, Oxford Martin School, Global Challenges Research Fund, Africa Oxford, and John Fell Fund.

epidemiology↗