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1.
BMC Public Health ; 22(1): 1446, 2022 07 29.
Article in English | MEDLINE | ID: mdl-35906590

ABSTRACT

The COVID-19 pandemic has had a significant impact on daily life, affecting both physical and mental health. Changes arising from the pandemic may longitudinally impact health-related behaviors (HRB). As different HRBs co-occur, in this study, we explore how six HRBs - alcohol (past-week and binge-drinking), tobacco, marijuana, benzodiazepine use, and unhealthy food consumption - were grouped and changed over time during the COVID-19 pandemic. A sample of 1038 university students and staff (18 to 73 years old) of two universities completed an online psychometrically adequate survey regarding their recalled HRB (T0, pre-COVID-19 pandemic) and the impact of COVID-19 on their behaviors during July (T1) and November (T2). Latent Transition Analysis (LTA) was used to identify HRB cluster membership and how clusters changed across T0, T1, and T2. Four clusters emerged, but remained mainly stable over time: 'Lower risk' (65.2-80%), 'Smokers and drinkers' (1.5-0.01%), 'Binge-drinkers and marijuana users' (27.6-13.9%), and 'Smokers and binge-drinkers' (5.6-5.8%). Participants who moved from one cluster to another lowered their HRB across time, migrating from the 'Binge-drinkers and marijuana users' cluster to 'Lower risk'. Participants in this cluster were characterized as less affected economically by the COVID-19 pandemic, with lower reported stress levels, anxiety, depression, and loneliness than the other clusters. Our results provide evidence of how HRBs clustered together and transitioned longitudinally during the COVID-19 pandemic. HRB clustering across time offers a valuable piece of information for the tailoring of interventions to improve HRB.


Subject(s)
COVID-19 , Adolescent , Adult , Aged , COVID-19/epidemiology , Cluster Analysis , Health Behavior , Humans , Middle Aged , Pandemics , Universities , Young Adult
2.
Rev Med Chil ; 150(10): 1299-1309, 2022 Oct.
Article in Spanish | MEDLINE | ID: mdl-37358088

ABSTRACT

BACKGROUND: Negative beliefs about vaccines can threaten herd immunity and pandemic control. Although beliefs about vaccines influence vaccination intention, there are no valid instruments that evaluate this in the Latin American population. AIM: To evaluate the psychometric properties of two scales that measure negative beliefs towards vaccines in general and against SARS-CoV-2 and provide evidence of their association with vaccination intention (convergent validity) in a Chilean sample. MATERIAL AND METHODS: Two studies were carried out. The first included 263 people who answered the beliefs towards vaccines in general scale (CV-G) and the beliefs towards the SARS-CoV-2 vaccine scale (CV-COVID). Exploratory factor analyses were conducted. In the second study, 601 people answered the same scales. Confirmatory factor analyses and structural equation modeling were performed to provide evidence of validity. RESULTS: Both scales had an unifactorial structure and excellent reliability and showed associations with the intention of vaccination against SARS-CoV-2, providing evidence of convergent validity. CONCLUSIONS: The scales evaluated here are reliable and valid measures that showed associations with vaccination intention in the Chilean population.


Subject(s)
COVID-19 , Vaccines , Humans , COVID-19 Vaccines , Psychometrics , Reproducibility of Results , COVID-19/prevention & control , SARS-CoV-2 , Vaccination , Intention
3.
Rev Med Chil ; 150(9): 1195-1205, 2022 Sep.
Article in Spanish | MEDLINE | ID: mdl-37358130

ABSTRACT

BACKGROUND: Negative beliefs about vaccines can threaten herd immunity and pandemic control. Although beliefs about vaccines influence vaccination intention, there are no valid instruments that evaluate this in the Latin American population. AIM: To evaluate the psychometric properties of two scales that measure negative beliefs towards vaccines in general and against SARS-CoV-2 and provide evidence of their association with vaccination intention (convergent validity) in a Chilean sample. MATERIAL AND METHODS: Two studies were carried out. The first included 263 people who answered the beliefs towards vaccines in general scale (CV-G) and the beliefs towards the SARS-CoV-2 vaccine scale (CV-COVID). Exploratory factor analyses were conducted. In the second study, 601 people answered the same scales. Confirmatory factor analyses and structural equation modeling were performed to provide evidence of validity. RESULTS: Both scales had an unifactorial structure and excellent reliability and showed associations with the intention of vaccination against SARS-CoV-2, providing evidence of convergent validity. CONCLUSIONS: The scales evaluated here are reliable and valid measures that showed associations with vaccination intention in the Chilean population.


Subject(s)
COVID-19 , Vaccines , Humans , COVID-19 Vaccines , Psychometrics , Reproducibility of Results , COVID-19/prevention & control , SARS-CoV-2 , Vaccination , Intention
4.
Mol Genet Metab ; 133(3): 242-249, 2021 07.
Article in English | MEDLINE | ID: mdl-34083144

ABSTRACT

CONTEXT: The clinical and laboratory features of dominant acute hepatic porphyrias (AHPs) in prepubertal children and adolescents have not been well established. OBJECTIVE: To evaluate clinical and laboratory features of AHPs in prepubertal children and adolescents compared to adults. DATA SOURCES: OVID (Embase Classic+Embase and MEDLINE), Scopus, and Google Scholar. STUDY SELECTION: Studies describing symptomatic children or adolescents (<18 years old) with increased urinary porphobilinogen were included. DATA EXTRACTION: Two reviewers independently extracted the data, with a third reviewer arbitrating discrepancies. RESULTS: 100 studies were included describing 112 patients (26 prepubertal children and 86 adolescents). Differences were found between prepubertal children and adolescents regarding sex distribution (female-to-male ratio: 1:2 vs. 4:1), clinical manifestations, and concomitant clinical manifestations. LIMITATIONS: There was variation in the methods used to diagnose porphyria attacks across studies, and some elements of the quality of individual studies were unclear. CONCLUSIONS: Prepubertal children with AHPs and porphyria attacks presented with distinct demographic and clinical characteristics from adolescents and adults. Nearly two-thirds of the affected children were males, and about half had a concomitant medical condition that can constitutively upregulate hepatic δ-aminolevulinic acid synthase-1. Adolescents were comparable to adults in almost all respects.


Subject(s)
Porphobilinogen Synthase/deficiency , Porphyrias, Hepatic/diagnosis , Porphyrias, Hepatic/physiopathology , Adolescent , Adult , Child , Female , Humans , Liver/pathology , Male , Sex Distribution
5.
Rev Med Chil ; 148(2): 196-203, 2020 Feb.
Article in Spanish | MEDLINE | ID: mdl-32730496

ABSTRACT

BACKGROUND: The Chilean population is aging rapidly. This socio-demographic change imposes psychosocial and economic challenges that are relevant for the health care of older people. AIM: To assess the association between perceived financial situation, perceived social support by friends, and age with health self-perception in older people. MATERIAL AND METHODS: A questionnaire about health self-perception, financial situation, and social support perceived by friends was applied to 383 occupationally active adults aged 68 ± 5 years (66% women) living in urban areas of Southern Chile. A gender-based multi-group path model was specified, which evaluated the association of health self-perception with the assessment of the financial situation, social support, and age. RESULTS: The final model was moderated by gender. However, age was not associated with health self-perception. For men and women, the perceived financial situation showed a positive association with health self-perception. The perceived social support of friends was only significant for women. CONCLUSIONS: The financial situation and friends' support (among women) are factors that should be considered in the evaluation of the health perception of older adults.


Subject(s)
Friends , Self Concept , Aged , Aging , Chile , Female , Humans , Male , Middle Aged , Social Support
6.
Proc Biol Sci ; 285(1886)2018 09 05.
Article in English | MEDLINE | ID: mdl-30185649

ABSTRACT

The behavioural composition of a group and the dynamics of social interactions can both influence how social animals work collectively. For example, individuals exhibiting certain behavioural tendencies may have a disproportionately large impact on the group, and so are referred to as keystone individuals, while interactions between individuals can facilitate information transmission about resources. Despite the potential impact of both behavioural composition and interactions on collective behaviour, the relationship between consistent behaviours (also known as personalities) and social interactions remains poorly understood. Here, we use stochastic actor-oriented models to uncover the interdependencies between boldness and social interactions in the social spider Stegodyphus dumicola We find that boldness has no effect on the likelihood of forming social interactions, but interactions do affect boldness, and lead to an increase in the boldness of the shyer individual. Furthermore, spiders tend to interact with the same individuals as their neighbours. In general, boldness decreases over time, but once an individual's boldness begins to increase, this increase accelerates, suggesting a positive feedback mechanism. These dynamics of interactions and boldness result in skewed boldness distributions of a few bold individuals and many shy individuals, as observed in nature. This group behavioural composition facilitates efficient collective behaviours, such as rapid collective prey attack. Thus, by examining the relationship between behaviour and interactions, we reveal the mechanisms that underlie the emergence of adaptive group composition and collective behaviour.


Subject(s)
Biological Variation, Individual , Spiders/physiology , Animals , Models, Biological , Personality , Social Behavior , Stochastic Processes
7.
Antonie Van Leeuwenhoek ; 111(8): 1421-1432, 2018 Aug.
Article in English | MEDLINE | ID: mdl-29626330

ABSTRACT

Northern Chile harbors different bioclimatic zones including hyper-arid and arid ecosystems and hotspots of microbial life, such as high altitude wetlands, which may contribute differentially to greenhouse gases (GHG) such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). In this study, we explored ground level GHG distribution and the potential role of a wetland situated at 3800 m.a.s.l, and characterized by high solar radiation < 1600 W m-2, extreme temperature ranges (-12 to 24 °C) and wind stress (< 17 m s-1). The water source of the wetland is mainly groundwater springs, which generates streams and ponds surrounded by peatlands. These sites support a rich microbial aquatic life including diverse bacteria and archaea communities, which transiently form more complex structures, such as microbial mats. In this study, GHG were measured in the water and above ground level air at the wetland site and along an elevation gradient in different bioclimatic areas from arid to hyper-arid zones. The microbiome from the water and sediments was described by high-throughput sequencing 16S rRNA and rDNA genes. The results indicate that GHG at ground level were variable along the elevation gradient potentially associated with different bioclimatic zones, reaching high values at the high Andean steppe and variable but lower values in the Atacama Desert and at the wetland. The water areas of the wetland presented high concentrations of CH4 and CO2, particularly at the spring areas and in air bubbles below microbial mats. The microbial community was rich (> 40 phyla), including archaea and bacteria potentially active in the different matrices studied (water, sediments and mats). Functional microbial groups associated with GHG recycling were detected at low frequency, i.e., < 2.5% of total sequences. Our results indicate that hyper-arid and arid areas of northern Chile are sites of GHG exchange associated with various bioclimatic zones and particularly in aquatic areas of the wetland where this ecosystem could represent a net sink of N2O and a source for CH4 and CO2.


Subject(s)
Altitude , Desert Climate , Ecosystem , Greenhouse Gases/analysis , Microbiota/physiology , Wetlands , Archaea/classification , Archaea/genetics , Archaea/metabolism , Bacteria/classification , Bacteria/genetics , Bacteria/metabolism , Biodiversity , Carbon Dioxide/analysis , Carbon Dioxide/metabolism , Chile , DNA, Archaeal/genetics , DNA, Bacterial/genetics , Geologic Sediments/microbiology , Greenhouse Gases/metabolism , Methane/analysis , Methane/metabolism , Nitrous Oxide/analysis , Nitrous Oxide/metabolism , RNA, Ribosomal/genetics , Ultraviolet Rays
8.
Nature ; 447(7147): 999-1002, 2007 Jun 21.
Article in English | MEDLINE | ID: mdl-17581584

ABSTRACT

The flux of organic material sinking to depth is a major control on the inventory of carbon in the ocean. To first order, the oceanic system is at equilibrium such that what goes down must come up. Because the export flux is difficult to measure directly, it is routinely estimated indirectly by quantifying the amount of phytoplankton growth, or primary production, fuelled by the upward flux of nitrate. To do so it is necessary to take into account other sources of biologically available nitrogen. However, the generation of nitrate by nitrification in surface waters has only recently received attention. Here we perform the first synthesis of open-ocean measurements of the specific rate of surface nitrification and use these to configure a global biogeochemical model to quantify the global role of nitrification. We show that for much of the world ocean a substantial fraction of the nitrate taken up is generated through recent nitrification near the surface. At the global scale, nitrification accounts for about half of the nitrate consumed by growing phytoplankton. A consequence is that many previous attempts to quantify marine carbon export, particularly those based on inappropriate use of the f-ratio (a measure of the efficiency of the 'biological pump'), are significant overestimates.


Subject(s)
Nitrites/metabolism , Seawater/chemistry , Carbon/metabolism , Ecosystem , Nitrites/analysis , Nitrogen/metabolism , Oceans and Seas , Plankton/metabolism , Seawater/analysis
9.
Neuropsychiatr ; 37(2): 80-87, 2023 Jun.
Article in English | MEDLINE | ID: mdl-36018476

ABSTRACT

BACKGROUND: The modulation hypothesis of facial feedback has not adequately examined how combining facial expressions and bodily postures might influence our experience of emotional stimuli. This pilot study examined a new method for manipulating both face and body together, which is important in furthering our understanding of how face and body interact to influence emotional experiences in the real world. METHODS: Using a within-subjects design, 30 participants viewed positive film clips under four conditions: (1) positive face with positive body (PP), (2) positive face with neutral body (PN), (3) neutral face with positive body (NP) and (4) neutral face with neutral body (NN). Measures of positive and negative affect were taken before and after each clip, to assess the subjective emotional experience. RESULTS: Repeated-measures analysis of variance (ANOVA) was conducted to examine differences in the emotional experience under each condition. Post hoc pairwise comparisons demonstrated that positive affect in the PP condition was significantly higher than in the NP and NN conditions. There was no significant difference between the PP and NN conditions. CONCLUSION: Whilst the study findings are difficult to interpret, this pilot study generated a number of important methodological learnings that are relevant to future research of this kind.


Subject(s)
Emotions , Facial Expression , Affect , Feedback , Pilot Projects , Posture
10.
Vaccines (Basel) ; 11(7)2023 Jun 25.
Article in English | MEDLINE | ID: mdl-37514966

ABSTRACT

The embrace of coronavirus disease 2019 (COVID-19) vaccine conspiracies has been linked to vaccine hesitancy. This study aimed to investigate the relationship between COVID-19 vaccine conspiracy theories and perceived vaccine effectiveness. The study utilized a longitudinal follow-up study in which adults in Chile completed surveys in December 2020 (T1) and May 2021 (T2). The psychometric properties of the five-item instrument on conspiracy theories for the COVID-19 vaccine were evaluated using data from T1 (n = 578). A confirmatory one-factor structure with suitable indicators of reliability was found. The longitudinal analysis (n = 292) revealed that conspiracy theories about the COVID-19 vaccine in T1 were associated with lower beliefs in its effectiveness in T2. However, no significant association was found between beliefs in effectiveness in T1 and conspiracy theories in T2. The study suggests that beliefs in conspiracy theories may temporally precede beliefs in vaccine effectiveness for COVID-19. The results have implications for strategies to address vaccine conspiracy beliefs and their implementation at the public policy level.

11.
Article in English | MEDLINE | ID: mdl-36981593

ABSTRACT

Health inequities exist in groups of greater psychosocial vulnerability such as emerging adults and migrants. The study aimed to generate evidence of the validity of the mental and physical health symptomatology scale in two samples of vulnerable groups: emerging university adults, who report high levels of mental health problems, and migrants, who report high levels of physical and mental health problems. Using non-probability sampling, in the first study, evidence of construct validity of the scale was reported in 652 emerging adults and, in the second, evidence of validity was provided from associations with the depression, stress and anxiety scale (DASS-21) among 283 migrants. The results indicate that in Study 1 the two-factor model had adequate indicators of fit and adequate reliability; only the mental health factor presented evidence of convergent validity. In Study 2, the mental health factor showed positive and large associations with the DASS-21, which decreased when the physical health symptoms factor was considered. These analyses provide evidence of validity for the scale, which is an easy-to-use instrument that allows for the assessment of health from an integral perspective.


Subject(s)
Mental Health , Stress, Psychological , Humans , Adult , Chile/epidemiology , Reproducibility of Results , Stress, Psychological/diagnosis , Physical Examination , Depression/psychology
13.
Mar Genomics ; 65: 100970, 2022 Oct.
Article in English | MEDLINE | ID: mdl-35839704

ABSTRACT

The giant mussel Choromytilus chorus is a marine bivalve commonly collected in central - southern Chile from fishery zones shared with the salmon industry. These economically relevant areas are also affected by the use of pesticides for controlling sea lice infestations in salmon aquaculture. Their main target is the sea louse Caligus rogercresseyi. However, other than some physiological impacts, the molecular effects of delousing drugs in non-target species such as C. chorus remain largely understudied. This study aimed to explore the transcriptome modulation of Trochophore and D larvae stages of C. chorus after exposure to azamethiphos and deltamethrin drugs. Herein, RNA-seq analyses and mRNA-lncRNAs molecular interactions were obtained. The most significant changes were found between different larval development stages exposed to delousing drugs. Notably, significant transcriptional variations were correlated with the drug concentrations tested. The biological processes involved in the development, such as cell movement and transcriptional activity, were mainly affected. Long non-coding RNAs (lncRNAs) were also identified in this species, and the transcription activity showed similar patterns with coding mRNAs. Most of the significantly expressed lncRNAs were associated with genes annotated to matrix metalloproteinases, collagenases, and transcription factors. This study suggests that exposure to azamethiphos or deltamethrin drugs can modulate the transcriptome signatures related to the early development of the giant mussel C. chorus.


Subject(s)
Bivalvia , Copepoda , Fish Diseases , RNA, Long Noncoding , Salmo salar , Animals , Bivalvia/genetics , Copepoda/genetics , Gene Expression Profiling , Salmo salar/genetics , Salmon/genetics , Transcriptome
14.
Mar Pollut Bull ; 177: 113480, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35305371

ABSTRACT

The water-sediment partitioning of flumequine and florfenicol, two antibiotics used in salmon aquaculture is a critical driver of their fate and environmental impact. Batch experiments, were carried out using pure water or seawater, with or without sediment, and at summer and winter temperatures of Chilean fjords. Log Kd (partition between water and sediment) of florfenicol in seawater varied from 0.62 ± 0.69 to 0.67 ± 0.13, and Log KOC (partition between water and organic fraction of sediment) from 2.15± 0.29 to 2.19 ± 0.13. Difference between KOC and the octanol-water partition constant (KOW) showed that for florfenicol, adsorption onto the surface of particles was more significant than the absorption driven by hydrophobicity whilst hydrophobic absorption was a major driver of flumequine sorption. Flumequine Log Kd (0.92 ± 0.25 to 1.36 ± 0.10) and Log KOC (from 2.44 ± 0.25 to 2.89 ± 0.10) demonstrated its greater affinity than florfenicol to particles and potential accumulation into marine sediments.


Subject(s)
Salmon , Water , Animals , Anti-Bacterial Agents , Aquaculture , Chile , Fluoroquinolones , Geologic Sediments/chemistry , Thiamphenicol/analogs & derivatives , Water/chemistry
15.
Article in English | MEDLINE | ID: mdl-36554406

ABSTRACT

The role of perceived social support in the acculturation process of immigrants remains unclear. In this study, we jointly evaluated the associations between acculturative stress and negative emotions associated with discrimination as antecedents of anxiety, depression, and stress symptoms in 283 immigrants living in Chile. Three competing models were tested via structural equation modelling to assess (1) the association among these variables and mental health symptoms and (2) to clarify the role of perceived social support. The third model was theoretically more adequate, showed a better fit, and explained 42.7% of the variance of mental health symptoms. In this model, perceived social support was associated with acculturative stress by reducing mental health symptomatology. Moreover, a direct relationship and an indirect relationship were found between acculturative stress (through negative emotions associated with discrimination) and mental health symptomatology. These results contribute to the understanding of the acculturation process experienced by immigrants in Chile and provide empirical evidence to be used to improve migration policies.


Subject(s)
Emigrants and Immigrants , Mental Health , Stress, Psychological/psychology , Acculturation , Anxiety , Social Support
16.
Front Microbiol ; 13: 862812, 2022.
Article in English | MEDLINE | ID: mdl-35592001

ABSTRACT

The activity of marine microorganisms depends on community composition, yet, in some oceans, less is known about the environmental and ecological processes that structure their distribution. The objective of this study was to test the effect of geographical distance and environmental parameters on prokaryotic community structure in the Southern Ocean (SO). We described the total (16S rRNA gene) and the active fraction (16S rRNA-based) of surface microbial communities over a ~6,500 km longitudinal transect in the SO. We found that the community composition of the total fraction was different from the active fraction across the zones investigated. In addition, higher α-diversity and stronger species turnover were displayed in the active community compared to the total community. Oceanospirillales, Alteromonadales, Rhodobacterales, and Flavobacteriales dominated the composition of the bacterioplankton communities; however, there were marked differences at the order level. Temperature, salinity, silicic acid, particulate organic nitrogen, and particulate organic carbon correlated with the composition of bacterioplankton communities. A strong distance-decay pattern between closer and distant communities was observed. We hypothesize that it was related to the different oceanic fronts present in the Antarctic Circumpolar Current. Our findings contribute to a better understanding of the complex arrangement that shapes the structure of bacterioplankton communities in the SO.

17.
Vaccines (Basel) ; 10(7)2022 Jul 15.
Article in English | MEDLINE | ID: mdl-35891293

ABSTRACT

(1) Background: Although the evidence is consistent that vaccines for COVID-19 effectively prevent severe illness or death, the rapid development of vaccines has led to increased beliefs about possible negative consequences and conspiracy theories about the vaccine. Several factors influence whether or not people decide to be vaccinated. Some studies suggest that our perception of what significant others do and think influences our behavior. (2) Methods: This study evaluates the predictive role of beliefs about negative consequences of the COVID-19 vaccine, conspiracy beliefs about this vaccine, and social influence on the intention to vaccinate against COVID-19 in three Latin American and Caribbean countries: Chile, Mexico, and Colombia. Using convenience sampling, 2075 adults from Chile (48.3%), Mexico (27.6%), and Colombia (24.6%) participated by answering an online questionnaire with variables of interest. (3) Results: Despite the differences between countries, the results showed that the proposed model is invariant and explains between 56-66% of the COVID-19 vaccination intent. Specifically, controlling for age, socioeconomic status, political orientation, and educational level, we found that beliefs about the negative consequences of the COVID-19 vaccine were the main predictor followed by social influence. Beliefs in conspiracy theories did not predict vaccination intention (4) Conclusions: Considering these variables in campaigns to boost vaccination intention is discussed.

18.
EMBO Mol Med ; 14(9): e15687, 2022 09 07.
Article in English | MEDLINE | ID: mdl-35919953

ABSTRACT

Inflammatory bowel disease (IBD) is characterized by dysregulated intestinal immune responses. Using mass cytometry (CyTOF) to analyze the immune cell composition in the lamina propria (LP) of patients with ulcerative colitis (UC) and Crohn's disease (CD), we observed an enrichment of CD4+ effector T cells producing IL-17A and TNF, CD8+ T cells producing IFNγ, T regulatory (Treg) cells, and innate lymphoid cells (ILC). The function of these immune cells is regulated by store-operated Ca2+ entry (SOCE), which results from the opening of Ca2+ release-activated Ca2+ (CRAC) channels formed by ORAI and STIM proteins. We observed that the pharmacologic inhibition of SOCE attenuated the production of proinflammatory cytokines including IL-2, IL-4, IL-6, IL-17A, TNF, and IFNγ by human colonic T cells and ILCs, reduced the production of IL-6 by B cells and the production of IFNγ by myeloid cells, but had no effect on the viability, differentiation, and function of intestinal epithelial cells. T cell-specific deletion of CRAC channel genes in mice showed that Orai1, Stim1, and Stim2-deficient T cells have quantitatively distinct defects in SOCE, which correlate with gradually more pronounced impairment of cytokine production by Th1 and Th17 cells and the severity of IBD. Moreover, the pharmacologic inhibition of SOCE with a selective CRAC channel inhibitor attenuated IBD severity and colitogenic T cell function in mice. Our data indicate that SOCE inhibition may be a suitable new approach for the treatment of IBD.


Subject(s)
Calcium Release Activated Calcium Channels , Inflammatory Bowel Diseases , Animals , CD8-Positive T-Lymphocytes/metabolism , Calcium/metabolism , Calcium Channels/metabolism , Humans , Immunity, Innate , Interleukin-17/metabolism , Interleukin-6/metabolism , Mice , ORAI1 Protein/metabolism , Stromal Interaction Molecule 1/genetics , Th17 Cells/metabolism
19.
Front Microbiol ; 12: 620220, 2021.
Article in English | MEDLINE | ID: mdl-34248861

ABSTRACT

Microorganisms play a crucial role in biogeochemical processes affecting the primary production and biogeochemical cycles of the ocean. In subpolar areas, the increment of the water temperature induced by climate change could lead to changes in the structure and activity of planktonic microbial communities. To understand how the structure of the microbial community in Chilean Patagonian fjords could be affected by climate change, we analyzed the composition of the prokaryotic community (bacteria-archaea) in two fjords (Pia and Yendegaia) with contrasting morphological and hydrological features. We targeted both the standing stock (16S rRNA genes) and the active fraction (16S rRNA transcripts) of the microbial communities during two consecutive austral winters. Our results showed that in both fjords, the active community had higher diversity and stronger biogeographic patterns when compared to the standing stock. Members of the Alpha-, Gamma-, and Deltaproteobacteria followed by archaea from the Marine Group I (Thaumarchaeota) dominated the active communities in both fjords. However, in Pia fjord, which has a marine-terminating glacier, the composition of the microbial community was directly influenced by the freshwater discharges from the adjacent glacier, and indirectly by a possible upwelling phenomenon that could bring deep sea bacteria such as SAR202 to the surface layer. In turn, in the Yendegaia, which has a land-terminating glacier, microbial communities were more similar to the ones described in oceanic waters. Furthermore, in Yendegaia fjord, inter-annual differences in the taxonomic composition and diversity of the microbial community were observed. In conclusion, Yendegaia fjord, without glacier calving, represents a fjord type that will likely be more common under future climate scenarios. Our results showing distinct Yendegaia communities, with for example more potential nitrogen-fixing microorganisms (Planctomycetes), indicate that as a result of climate change, changing planktonic communities could potentially impact biogeochemical processes and nutrient sources in subantarctic fjords.

20.
Sci Total Environ ; 768: 144370, 2021 May 10.
Article in English | MEDLINE | ID: mdl-33454466

ABSTRACT

The landscapes of high-altitude wetland ecosystems are characterized by different kinds of aquatic sites, including ponds holding conspicuous microbial life. Here, we examined a representative pond of the wetland landscape for dynamics of greenhouse gases, and their association with other relevant biogeochemical conditions including diel shifts of microbial communities' structure and activity over two consecutive days. Satellite image analysis indicates that the area of ponds cover 238 of 381.3 Ha (i.e., 62.4%), representing a significant landscape in this wetland. Solar radiation, wind velocity and temperature varied daily and between the days sampled, influencing the biogeochemical dynamics in the pond, shifting the pond reservoir of inorganic versus dissolved organic nitrogen/phosphorus bioavailability, between day 1 and day 2. Day 2 was characterized by high dissolved organic nitrogen/phosphorus and N2O accumulation. CH4 presented a positive excess showing maxima at hours of high radiation during both days. The microbial community in the sediment was diverse and enriched in keystone active groups potentially related with GHG recycling including bacteria and archaea, such as Cyanobacteria, Verrucomicrobia, Rhodobacterales and Nanoarchaeaota (Woesearchaeia). Archaea account for the microbial community composition changes between both days and for the secondary productivity in the water measured during day 2. The results indicate that an intense recycling of organic matter occurs in the pond systems and that the activity of the microbial community is correlated with the availability of nutrients. Together, the above results indicate a net sink of CO2 and N2O, which has also been reported for other natural and artificial ponds. Overall, our two-day fluctuation study in a representative pond of a high-altitude wetland aquatic landscape indicates the need to explore in more detail the short-term besides the long-term biogeochemical variability in arid ecosystems of the Andes plateau, where wetlands are hotspots of life currently under high anthropogenic pressure.


Subject(s)
Greenhouse Gases , Altitude , Archaea , Bacteria , Greenhouse Gases/analysis , Methane/analysis , Wetlands
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