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El uso de nano y microbots como tratamiento para tumores cancerígenos, tuvo avances acelerados durante los últimos años, debido a esto se consideró pertinente realizar esta revisión documental. Se llevó a cabo una búsqueda exhaustiva del avance de su aplicación actual, su funcionamiento y las ventajas y desventajas de su utilización. Varios modelos nano y microbots están inspirados en bacterias y otros organismos vivos, por sus propiedades en el tratamiento del cáncer. Por su parte, las nanomedicinas tienen ventajas en comparación con la administración convencional de fármacos, la combinación de estos conceptos da como resultado, un tratamiento de tumores cancerígenos más efectivo. Actualmente los desafíos a los que se enfrentan los nano y microbots son: sobrevivir, por ejemplo, al sistema inmunológico; localizar al tumor y ser ubicados por operadores humanos, realizar la operación específica de liberación de fármacos y ser eliminados del cuerpo una vez completada su misión. En la evolución de los micro y nanobots, cada vez existen modelos más eficientes y esto puede traducirse en grandes beneficios, siendo el principal la reducción de efectos secundarios, debido al sistema de liberación precisa del fármaco.

In COVID-19 neurological alterations are noticed during the systemic viral infection. Various pathophysiological mechanisms on the central nervous system (CNS) have been suggested in the past two years, including the viral neurotropism hypothesis. Nevertheless, neurological complications can also occur independent of neurotropism and at different stages of the disease and may be persistent.Previous autopsy studies of the CNS from patients with severe COVID-19 show infiltration of macrophages and T lymphocytes, especially in the perivascular regions as well as pronounced microglial activation, but without signs of viral encephalitis.However, there is an ongoing debate about long-term changes and cytotoxic effects in the CNS due to the systemic inflammation.Here, we show the brain-specific host response during and after COVID-19. We profile single-nucleus transcriptomes and proteomes of brainstem tissue from deceased COVID-19 patients who underwent rapid autopsy. We detect a disease phase-dependent inflammatory type-I interferon response in acute COVID-19 cases. Integrating single-nucleus RNA sequencing and spatial transcriptomics, we could localize two patterns of reaction to severe systemic inflammation. One neuronal with direct focus on cranial nerve nuclei and one diffusely affecting the whole brainstem, the latter reflecting a bystander effect that spreads throughout the vascular unit and alters the transcriptional state of oligodendrocytes, microglia and astrocytes.Our results indicate that even without persistence of SARS-CoV-2 in the CNS, the tissue activates highly protective mechanisms, which also cause functional disturbances that may explain the neurological symptoms of COVID-19, triggered by strong systemic type-I IFN signatures in the periphery.

In Colombia, around 70% of the energy is from hydropower source and most of its associated hydraulic infrastructure is located in the macro-basin of the Magdalena and Cauca rivers. These projects are generating a drainage network fragmentation and a substantial alteration in natural regimes of both flow and sediment, which is having negative impacts on freshwater ecosystems and their ecosystem services. Nowadays, there is a methodology related to environmental flows, proposed in 2018 by the Colombian Ministry of Environmental and Sustainable Development (not adopted as a regulation), which integrates two sets of stakeholders: environmental authorities for integrated water resources management at regional scale and holders of new projects with high impact on the natural flow regime of rivers. Since it is only a non-binding methodological proposal, there are no known practical applications to evaluate its effectiveness in terms of reduction of environmental impacts, social conflicts, and water governance. In this sense, we propose a step forward in the analysis of the effects of its application in rivers with available hydrological data and under natural regime conditions through a taylor-made computer model (HeCCA 1.0) which is composed of the most important methods contemplated in the above-mentioned methodology.HeCCA 1.0 allows determining the percentage of monthly use of a river without compromising its ecosystem function, based on it, river discharge data of 15 different watersheds located throughout the entire country were used. In this test, a range of drainage areas (180 to 73000 km2) was covered located between 25 and 2993 meters above sea level. The systems belong to different seasonal behaviors depending on the geographical location (monomodal or bimodal). For the monomodal regime, utilization percentages were obtained between the 61%8 and 77%29; and for bimodal regimen between 14% and 49%32.These results depend on the geographical location of the basin, the watershed size, if it is related to the runoff seasonality along the year in the different catchment areas of the country. The taylor-made computer model provides stakeholders a holistic overview of the water availability and management, giving quantitative tools for an optimal development of water governance in the region.

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 ( 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.

Neurodegenerative diseases are a heterogeneous group of maladies, characterized by progressive loss of neurons. These diseases involve an intricate pattern of cross-talk between different types of cells to maintain specific signaling pathways. A component of such intercellular cross-talk is the exchange of various types of extracellular vesicles (EVs). Exosomes are a subset of EVs, which are increasingly being known for the role they play in the pathogenesis and progression of neurodegenerative diseases, e.g., synucleinopathies and tauopathies. The ability of the central nervous system exosomes to cross the blood–brain barrier into blood has generated enthusiasm in their study as potential biomarkers. However, the lack of standardized, efficient, and ultra-sensitive methods for the isolation and detection of brain-derived exosomes has hampered the development of effective biomarkers. Exosomes mirror heterogeneous biological changes that occur during the progression of these incurable illnesses, potentially offering a more comprehensive outlook of neurodegenerative disease diagnosis, progression and treatment. In this review, we aim to discuss the challenges and opportunities of peripheral biofluid-based brain-exosomes in the diagnosis and biomarker discovery of Alzheimer’s and Parkinson’s diseases. In the later part, we discuss the traditional and emerging methods used for the isolation of exosomes and compare their advantages and disadvantages in clinical settings.

In this study, we used stable isotopes of oxygen (��18O), deuterium (��D), and dissolved inorganic carbon (��13CDIC) in combination with temperature, salinity, oxygen, and nutrient concentrations to characterize the coastal (71�����78��W) and an oceanic (82�����98��W) water masses (SAAW���Subantarctic Surface Water; STW���Subtropical Water; ESSW���Equatorial Subsurface water; AAIW���Antarctic Intermediate Water; PDW���Pacific Deep Water) of the Southeast Pacific (SEP). The results show that ��18O and ��D can be used to differentiate between SAAW-STW, SAAW-ESSW, and ESSW-AAIW. ��13CDIC signatures can be used to differentiate between STW-ESSW (oceanic section), SAAW-ESSW, ESSW-AAIW, and AAIW-PDW. Compared with the oceanic section, our new coastal section highlights differences in both the chemistry and geometry of water masses above 1,000 m. Previous paleoceanographic studies using marine sediments from the SEP continental margin used the present-day hydrological oceanic transect to compare against, as the coastal section was not sufficiently characterized. We suggest that our new results of the coastal section should be used for past characterizations of the SEP water masses that are usually based on continental margin sediment samples.

We studied the input of ammonium coming from the dissolution of food pellets commonly used in salmon farming as well as its potential for mineralization via ammonification and ammonium oxidation by natural bacterioplankton communities. Through experiments in central and southern Chile, we evaluated the potential for photo‐ and bio‐ammonification of food pellets in surface and subsurface waters (30 m depth) using irradiated (PAR + UV; IPS) and non‐irradiated dissolved‐pellet solutions (NIPS). Ammonium release was observed in both IPS and NIPS treatments and occurred at short time scales (

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.

In Colombia around 70% of the electricity generation is from hydropower. It is documented that their infrastructure and operation rules affect the natural regime of flows and sediments with several impacts on aquatic ecosystem functioning mainly on the Magdalena-Cauca river basin, where most of the projects are located. Also, social conflicts have been documented downstream hydropower projects due to water use incompatibilities. Considering that Colombia has a great potential to expand hydropower generation as well as there is a growing demand from other water users, it is necessary to attend the ecological requirements of aquatic ecosystems and to improve the water management in order to avoid irreversible environmental impacts and governance problems.In 2018, the Colombian Ministry of Environmental and Sustainable Development (MADS) developed a methodology to consider environmental flows both in the water management decisions and in the environmental impact assessment of new projects with impacts on hydrologic regimen. The opportunity to carry out a validation of its premises aims to research its effectiveness in terms of reduction in hydrologic alterations when environmental flow allocation is decided. That is why we have developed a computer model (HeCCA 1.0) which contains the most important methods contemplated in the methodology proposed by MADS. Thus, using river discharge data of 15 different river systems located throughout the entire country, the methodology mentioned has been tested in basins with low anthropic alteration of the hydrological regime. In this test, we cover a range of drainage areas, from 180 to 73000 km2, located between 25 and 2993 meters above sea level, and different climatic and geomorphological characteristics. The following results have been obtained using the HeCCA tool. For the 15 river systems, the statistical quartiles Q1, Q2 and Q3 for the percentage of use are monthly correspond to 24%, 47% and 100% respectively. The systems belong to different seasonal behaviors depending on the geographical location; nine of them count on a monomodal regimen, which average percentage of use is 61%±8, and the highest percentages of use (located in the Pacific basin) are not found during the wettest months, (77%±29); four of the watersheds are in the Orinoco basin, providing use of water between 61% and 67%. Six systems have bimodal regimen, whose average percentage of use is 49%±32, the two lowest percentages of use (14% and 19%) are found in the biggest bimodal watersheds, with sizes over 1700km2, which also have the highest average yields. The highest percentage of use found during the wettest months of the year is 99%, corresponding to the system located at one of the lowest points of the Caribbean basin. Thus, the percentage of available water depends on the watershed size, if it is related to the runoff seasonality along the year in the different catchment areas of the country. This approach provides stakeholders a clear overview of the water availability and management through a useful tool which improves the integral water management for hydrological systems.

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.

Salar de Huasco is a high-altitude (3800 m a.s.l.) polyextreme aquatic environment located in the Chilean Altiplano. This chapter highlights over 15 years of microbial ecology research conducted in this fascinating system covering microbial diversity, microbial adaptation to extreme conditions, and the role of microbes in biogeochemical cycles, including the recycling of greenhouse gases. Salar de Huasco is representative of other active saline wetlands in the same area harboring a high biodiversity. The important spatial and temporal variability of this ecosystem configure a unique environment for the study of the diversity and function of microbial communities. Salar de Huasco supports very high microbial diversity: studies so far have identified the presence of more than 50% of all bacterial phyla and the three archaeal superphylum described globally. Eukaryotic communities have been less studied, but recent efforts have highlighted their high endemism in Salar de Huasco. Microbial communities have been shown to play an active role in nitrogen, carbon, and sulfur cycles, intensely recycling greenhouse gases and representing a source of CH4, CO2, and a sink of N2O in this ecosystem. It has become apparent that microbial communities in the salar are highly adapted to polyextreme conditions, allowing them to withstand simultaneous environmental stressors, including extremely high solar radiation, salinity, and marked diel shifts in temperature. The production of compatible solutes within the microbial community plays a key role as a protection mechanism against such harmful conditions. Notwithstanding the concerted efforts by both our group and other colleagues to understand the dynamic of the microbiome in Salar de Huasco, many unsolved questions remain, especially regarding biological and ecological interactions within the microbial communities, as well as other temporal and spatial factors. Evaporitic basins in the Andes are currently under marked threat, largely due to extraction of water to support mining, and there is an urgent and pressing need to preserve and conserve this still understudied environment.

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 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.

Aquaculture has become an important component of Chilean economy, especially in the southern region, where salmon farming is an active industry. However, high density in salmon cages can increase stress and susceptibility to parasitic outbreaks of the copepod Caligus rogercresseyi. The pesticides used against sea lice can have potential effects on non-target microbiota and on the structure and functioning of aquatic ecosystems. The objective of this study was to investigate the response of natural microbial communities to the addition of the anti-lice pesticides azamethiphos, deltamethrin and emamectin benzoate and their potential impact on photoautotrophic and chemoautotrophic carbon fixation in central-southern Chile (37°S to 42°S). The addition of pesticides on primary production samples was related to changes in carbon uptake, which were significant if a single pesticide was applied, mainly emamectin benzoate and azametiphos. In surface waters of central Chile, emamectin benzoate produced a 60–90% decrease for both photo and chemoautotrophic carbon fixation. Enhanced rates were also observed for in situ primary production as a result of azamethiphos addition in northern Patagonia. Such stimulation, although limited, was possibly related to the supply of nitrogen and phosphate for phytoplankton requirements by this organophosphate compound.

This article presents a case study of a victim murdered in 2008 and found in a clandestine burial. The body was found in 2019 outside a rural residence in the province of Mendoza, Argentina. The article’s objective is to demonstrate the relevance of having archaeologists and anthropologists on-site and the importance of multidisciplinary laboratory analysis as part of a continuous process of investigation. The search, location, exhumation, and interpretation of the burial was carried out using archaeological methods. In the laboratory, we reconstructed the biological profile and cause of death using forensic anthropology, dentistry, image diagnosis, and genetics. The postmortem interval and history were reconstructed from the entomological and taphonomic analyses. The individual’s identity was confirmed and the evidence made it possible to locate and prosecute those responsible for the murder. Finally, the classic indicators of burial are discussed in relation to those found in the case study presented here. The unsystematic techniques used by the scientific police in cases of buried corpses are also critically assessed. We reflect on the importance of collecting adequate scientific evidence to support a legal case.

The role of zooplankton in microbial nitrogen turnover in marine environments is poorly understood. Here, we present results from two experiments designed to determine the excretion rate of ammonium and dissolved organic nitrogen (DON) by dominant copepods, Acartia tonsa and Paracalanus cf indicus, fed with two natural sized-fractioned diets (20–150 μm and

Groups of social predators capture large prey items collectively, and their social interaction patterns may impact how quickly they can respond to time-sensitive predation opportunities. We investigated whether various organizational levels of resting interactions (individual, sub-group, group), observed at different intervals leading up to a collective prey attack, impacted the predation speed of colonies of the social spider Stegodyphus dumicola. We found that in adult spiders overall group connectivity (average degree) increased group attack speed. However, this effect was detected only immediately before the predation event; connectivity two and four days before prey capture had little impact on the collective dynamics. Significantly, lower social proximity of the group’s boldest individual to other group members (closeness centrality) immediately prior and two days before prey capture was associated with faster attack speeds. These results suggest that for adult spiders, the long-lasting effects of the boldest individual on the group’s attack dynamics are mediated by its role in the social network, and not only by its boldness. This suggests that behavioural traits and social network relationships should be considered together when defining keystone individuals in some contexts. By contrast, for subadult spiders, while the group maximum boldness was negatively correlated with latency to attack, no significant resting network predictors of latency to attack were found. Thus, separate behavioural mechanisms might play distinctive roles in determining collective outcomes at different developmental stages, timescales, and levels of social organization.Significance statementCertain animals in a group, such as leaders, may have a more important role than other group members in determining their collective behavior. Often these individuals are defined by their behavioral attributes, for example, being bolder than others. We show that in social spiders both the behavioral traits of the influential individual, and its interactions with other group members, shape its role in affecting how quickly the group collectively attacks prey.

Summary We report the seasonal and single-diurnal variability of potentially active members of the prokaryote community in coastal surface waters off central Chile and the relationship between nitrifiers and solar radiation by combining 16S cDNA-based pyrosequencing, RT-qPCR of specific gene markers for nitrifiers (amoA, for general AOA, AOA-A, AOA-B, Nitrosopumilus maritimus and beta-AOB; and 16S rRNA gene for Nitrospina-like NOB), and solar irradiance measurements. We also evaluated the effects of artificial UVA-PAR and PAR spectra on nitrifiers by RT-qPCR. All nitrifiers (except AOA-B ecotype) were detected via RT-qPCR but AOA was the only group detected by pyrosequencing. Results showed high variability in their transcriptional levels during the day which could be associated to sunlight intensity thresholds in winter although AOA and Nitrospina-like NOB transcript number were also potentially related with environmental substrate availability. Only N. maritimus amoA transcripts showed a significant negative correlation with solar irradiances in both periods. During spring-summer, Nitrospina transcripts decreased at higher sunlight intensities, whereas the opposite was found during winter under natural (in situ) and artificial light experiments. In summary, a nitrifying community with variable tolerance to solar radiation is responsible for daily nitrification, and was particularly diverse during winter in the study area.

High-altitude wetland holds freshwater springs, evaporitic ponds and lagoon with variable salinity and nutrients, potentially influencing the ecology of nitrifying communities. In this study, nitrifying microorganisms in Salar de Huasco (Chile) were surveyed to determine bacterial and archaeal contribution to ammonium (AO), nitrite oxidation (NO), ammonium uptake (AU) during wet and dry seasons. The activity signals from these groups were assessed by specific amoA-qPCR transcription, 15N tracer studies and addition of group specific inhibitor experiments for nitrifying microorganisms (N1-guanyl-1, 7-diaminoheptane [GC7]-archaeal specific and allylthiourea [ATU]-bacterial specific). Nitrifying communities, i.e. Nitrosopumilus, Nitrosospira, Nitrosomonas, Kuenenia and Nitrospira, were more frequent (∼0.25% of 16S rRNA sequences) at low salinity sites. Bacterial amoA-qPCR transcripts also increased at low salinity and along in situ ammonium increase observed between wet/dry seasons. Nutrient changes through time and 15N tracer experiments results showed that AO and NO were detected and peaked mainly at low salinity-high ammonium sites (0.3 μM), whereas AU was predominant at evaporitic sites. Our results indicate that salinity and ammonium affect the nitrifying communities that are potentially more active at low-salinity sites but persistent at saltier evaporitic areas of the wetland when ammonium is available.

Zooplankton play a key role in the regeneration of nitrogen and phosphorus in the ocean through grazing and metabolism. This study investigates the role of the organic and inorganic nitrogen and phosphorus compounds released by copepods on biogeochemical processes and on the microbial community composition during the OUTPACE cruise (18 February–3 April 2015) at three long duration stations (LD). Two LD stations were located in the Melanesian Archipelago region (MA; LD A and LD B) and one in the South Pacific Gyre (SG; LD C), which represent oligotrophic and ultraoligotrophic regions respectively. At each station, microcosm onboard experiments were performed with locally sampled organisms, comprising a mix of epipelagic copepods fed with their natural food and then incubated along with wild microbial assemblages. In presence of copepods, ammonium and dissolved organic nitrogen showed a significant increase, compared to a control in two situations: in ammonium concentration (increasing rate: 0.29 μmol L−1 h−1 after 4 h of incubation) in LD C and in dissolved organic nitrogen concentration (rate: 2.13 μmol L−1 h−1 after 0.5 h of incubation) in LD A. In addition, during the three experiments, an enhanced remineralization (ammonification and nitrification) was observed when adding copepods compared to the controls. A shift in the composition of active bacterial community was observed for the experiments in LD A and LD B mainly characterized by an increase in Alteromonadales and SAR11, respectively and linked with changes in nutrient concentrations. In the experiment performed in LD C, both groups increased but at different periods of incubation, Alteromonadales between 1 and 2 h after the beginning of the experiment, and SAR 11 at the end of incubation. Finally, our experimental results in near in situ conditions, show that copepods can be a source of organic and inorganic compounds for bacterial communities, which respond to excretion pulses at different scales, depending on the initial environmental conditions and on their community composition. These processes can contribute significantly to nutrient recycling in the epipelagic ecosystem of ultra and oligotrophic oceanic regions.

Although N2 fixation could represent a supplementary source of bioavailable nitrogen in coastal upwelling areas and underlying oxygen minimum zones (OMZs), the limited data available prevent assessing its variability and biogeochemical significance. Here we report the most extensive N2 fixation data set gathered to date in the upwelling area off central Chile (36°S). It covers interannual to high frequency time scales in an area of about 82,500 km2 in the eastern South Pacific (ESP). Because heterotrophic N2 fixation may be regulated by DOM availability in the ESP, we conducted experiments at different oxygen conditions and included DOM amendments in order to test diazotrophic activity. Rates in the euphotic zone showed strong temporal variability which resulted in values reaching 0.5 nmol L−1 d−1 in 2006 (average 0.32 ± 0.17 nmol L−1 d−1) and up to 126.8 nmol L−1 d−1 (average 24.75 ± 37.9 nmol L−1 d−1) in 2011. N2 fixation in subsurface suboxic conditions (1.5 ± 1.16 nmol L−1 d−1) also occurred mainly during late summer and autumn while virtually absent in winter. The diversity of diazotrophs was dominated by heterotrophs, with higher richness in surface compared to OMZ waters. Rates in oxygen depleted conditions could exceed values obtained in the euphotic layer, but rates were not dependent on the availability of dissolved organic matter. N2 fixation also showed a positive correlation with total chlorophyll and the C:N ratio of phytoplankton, but not to the P excess compared to N. We conclude that the diazotrophic community responds to the composition of phytoplankton rather than the extent of N deficiency and the availability of bulk DOM in this system.

Building capacity within health and education systems of low- and middle-income countries in order to deliver high-quality early childhood services requires coordinated efforts across sectors, effective governance, sufficient funding, an adequate workforce, reliable data systems, and continuous monitoring, evaluation, and improvement cycles; it also requires partnerships with the private sector, communities, and parents. In addition, building capacity requires leadership, innovation of strategies to fit into existing structures, evidence-based intervention models, and effective partnerships that help make interventions more culturally relevant, help finance them, and help create institutional long-term support and sustainability for them. In this article, we focus on identifying eight critical aspects of enabling systemic support for early childhood services. Every action that strengthens these critical aspects should be seen as necessary, but insufficient, steps toward a national strong governance structure for delivering a locally relevant and comprehensive early child development program that promotes children's developmental potentials.

Blanchet, Marine ... et al.-- 17 pages, 7 figures, 3 tables, supplementary material https://dx.doi.org/10.1007/s00027-016-0477-0, Heterotrophic bacterial communities in marine environments are exposed to a heterogeneous mixture of dissolved organic compounds with different bioreactivity that may control both their activity and composition. The coastal environment is an example of a mixing area where recalcitrant allochthonous organic matter from rivers can encounter labile organic matter from marine phytoplanktonic blooms. The objective of this study was to explore the effects of mixed qualities of dissolved organic matter (DOM) on bacterial community activity (BCA) and bacterial community composition (BCC) and to test for a priming effect when DOM sources are added in combination. Coastal marine bacterial communities were incubated separately with a mixture of amino acids and with natural riverine DOM or with both sources together for 42 days. Addition of amino acids alone or in combination with riverine DOM led to a similar stimulation of BCA compared to control condition, whereas addition of riverine DOM alone did not modify BCA compared to the control. On the contrary, BCC analyzed by 16S rRNA gene pyrosequencing was not affected by the addition of amino acids alone, but changed dramatically with riverine DOM alone or in combination with amino acids. Our results show that changes in BCA and BCC can be driven by different types of DOM, but that these changes are not necessarily coupled. Moreover, the addition of labile DOM did not modify the microbial decomposition of riverine DOM, nor the BCC, suggesting that a priming effect did not occur under these experimental conditions, This research was funded by the French program EC2CO/CNRS-INSU through the IMPEC project. Rhône River discharge data were provided by MOOSE (Mediterranean Oceanic Observing System on Environment) with the support of the “Agence de l’Eau Rhône-Méditerranée et Corse”. MB was supported by a PhD grant from the French Ministry of Research. C.M. and F.L. Aparicio received support from Ministerio de Economía y Competititvidad (DOREMI project, CTM2012-34294)

γ-Al 2 O 3 support was modified with zirconia by the grafting method, using zirconium(IV) n-propoxide as precursor. Rh catalysts were prepared by wet impregnation of pure γ-Al 2 O 3 (Rh/A), Zr modified γ-Al 2 O 3 (Rh/100Z-A), and pure ZrO 2 (Rh/Z) supports. Rh/A presents a good activity in dry reforming of methane and exhibits a high amount of surface oxidized rhodium (92% of surface Rh atoms) after the reaction. Rh/Z is poorly active and 45% of Rh surface atoms remain reduced during the reaction. The catalytic activity significantly increased when using Rh/100Z-A. Tetragonal ZrO 2 crystallites are formed on the surface of modified alumina. It was obtained that, after Rh deposition, the grafted catalyst is composed by Rh/A and Rh/Z, as separated catalytic particles in good contact. To further understand the high activity of the grafted catalyst, mechanical mixtures of Rh/A and Rh/Z catalysts were synthesized. Compared with the single catalysts, an important synergistic effect in methane conversion and yields to CO and H 2 was observed when high amounts of Rh/A were mixed with Rh/Z catalyst, along with a promotion of rhodium oxidation in Rh/Z, which leads to a high surface fraction of RhO x (88%) in the mixture. The formation of mixed phases between the supports and the migration of Rh atoms from one phase to the other were discarded. It is suggested that a catalytic cooperation occurs due to the presence and mobility of oxygen species generated by the dissociation of CO 2 on Rh/A, which migrate to the Rh/Z catalyst promoting the oxidation of rhodium at its surface, and the catalytic activity. This cooperation mechanism is also expected to operate in the Rh/100Z-A catalyst, between the Rh/A and Rh/Z particles present in the surface. The importance of oxidized Rh for dry reforming of methane is evident from the high catalytic activity achieved when highly oxidized rhodium atoms are present together with the metallic Rh sites where methane activation occurs. © 2014 Elsevier B.V.

Summary Aerobic nitrite oxidation in marine environments plays a key role in the nitrification process. Marine bacteria involved in this nitrate-producing process have however been seldom studied compared with the ammonia-oxidizing community. Here, we report for the first time the community structure of aerobic nitrite-oxidizing bacteria (NOB) in the seasonal upwelling and oxygen-deficient area off Central Chile. Analysis of 16S rRNA by tag pyrosequencing was combined with specific quantitative polymerase chain reaction (qPCR) and reverse transcription qPCR in summer and wintertime. Nitrospina-like bacteria were the only known NOB detected by means of pyrosequencing between 30 and 80 m depth, accounting for up to 5% of total bacteria. This guild was represented by 11 and 7 operational taxonomic units (97% cut-off) in winter and summertime respectively. Nitrospina-like bacteria were phylogenetically related to sequences retrieved from coastal upwelling, oxygen minimum zones and deep-sea environments. This group was also detected by qPCR with abundances that increased with depth throughout the water column. Importantly, Nitrospina from surface layers showed low abundances but high 16S rRNA : rDNA ratios and mainly in summertime. Overall, our results highlight the seasonal variability between the structure and physiological state of this community and suggest a significant role of Nitrospina in the nitrogen cycle of seasonal upwelling areas.

International audience; Cyanobacteria from Subsection V (Stigonematales) are important components of microbial mats in non-acidic terrestrial hot springs. Despite their diazotrophic nature (N2 fixers), their impact on the nitrogen cycle in such extreme ecosystems remains unknown. Here, we surveyed the identity and activity of diazotrophic cyanobacteria in the neutral hot spring of Porcelana (Northern Patagonia, Chile) during 2009 and 2011–2013. We used 16S rRNA and the nifH gene to analyze the distribution and diversity of diazotrophic cyanobacteria. Our results demonstrate the dominance of the heterocystous genus Mastigocladus (Stigonematales) along the entire temperature gradient of the hot spring (69–38 °C). In situ nitrogenase activity (acetylene reduction), nitrogen fixation rates (cellular uptake of 15N2) and nifH transcription levels in the microbial mats showed that nitrogen fixation and nifH mRNA expression were light-dependent. Nitrogen fixation activities were detected at temperatures ranging from 58 °C to 46 °C, with maximum daily rates of 600 nmol C2H4 cm−2 per day and 94.1 nmol N cm−2 per day. These activity patterns strongly suggest a heterocystous cyanobacterial origin and reveal a correlation between nitrogenase activity and nifH gene expression during diurnal cycles in thermal microbial mats. N and C fixation in the mats contributed ~3 g N m−2 per year and 27 g C m−2 per year, suggesting that these vital demands are fully met by the diazotrophic and photoautotrophic capacities of the cyanobacteria in the Porcelana hot spring.

We report the seasonal and single-diurnal variability of potentially active members of the prokaryote community in coastal surface waters off central Chile and the relationship between nitrifiers and solar radiation by combining 16S cDNA-based pyrosequencing, RT-qPCR of specific gene markers for nitrifiers (amoA, for general AOA, AOA-A, AOA-B, Nitrosopumilus maritimus and beta-AOB; and 16S rRNA gene for Nitrospina-like NOB), and solar irradiance measurements. We also evaluated the effects of artificial UVA-PAR and PAR spectra on nitrifiers by RT-qPCR. All nitrifiers (except AOA-B ecotype) were detected via RT-qPCR but AOA was the only group detected by pyrosequencing. Results showed high variability in their transcriptional levels during the day which could be associated to sunlight intensity thresholds in winter although AOA and Nitrospina-like NOB transcript number were also potentially related with environmental substrate availability. Only N. maritimus amoA transcripts showed a significant negative correlation with solar irradiances in both periods. During spring-summer, Nitrospina transcripts decreased at higher sunlight intensities, whereas the opposite was found during winter under natural (in situ) and artificial light experiments. In summary, a nitrifying community with variable tolerance to solar radiation is responsible for daily nitrification, and was particularly diverse during winter in the study area.

Although the Southern Ocean is considered a high-nutrient, low-chlorophyll (HNLC) area, massive and recurrent blooms are observed over and downstream of the Kerguelen Plateau. This mosaic of blooms is triggered by a higher iron supply resulting from the interaction between the Antarctic Circumpolar Current and the local bathymetry. Net primary production, N uptake (NO3− and NH4+), and nitrification rates were measured at eight stations in austral spring 2011 (October–November) during the KEOPS 2 cruise in the Kerguelen Plateau area. Natural iron fertilization stimulated primary production, with mixed layer integrated net primary production and growth rates much higher in the fertilized areas (up to 315 mmol C m−2 d−1 and up to 0.31 d−1 respectively) compared to the HNLC reference site (12 mmol C m−2 d−1 and 0.06 d−1 respectively). Primary production was mainly sustained by nitrate uptake, with f ratios (corresponding to NO3−-uptake / (NO3−-uptake + NH4+-uptake)) lying at the upper end of the observations for the Southern Ocean (up to 0.9). We report high rates of nitrification (up to ~ 3 μmol N L−1 d−1, with ~ 90 % of them < 1 μmol N L−1 d−1) typically occurring below the euphotic zone, as classically observed in the global ocean. The specificity of the studied area is that at most of the stations, the euphotic layer was shallower than the mixed layer, implying that nitrifiers can efficiently compete with phytoplankton for the ammonium produced by remineralization at low-light intensities. Nitrate produced by nitrification in the mixed layer below the euphotic zone is easily supplied to the euphotic zone waters above, and nitrification sustained 70 ± 30 % of the nitrate uptake in the productive area above the Kerguelen Plateau. This complicates estimations of new production as potentially exportable production. We conclude that high productivity in deep mixing system stimulates the N cycle by increasing both assimilation and regeneration., info:eu-repo/semantics/published

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.

The high availability of electron donors occurring in coastal upwelling ecosystems with marked oxyclines favours chemoautotrophy, in turn leading to high N2O and CH4 cycling associated with aerobic NH4+ (AAO) and CH4 oxidation (AMO). This is the case of the highly productive coastal upwelling area off central Chile (36° S), where we evaluated the importance of total chemolithoautotrophic vs. photoautotrophic production, the specific contributions of AAO and AMO to chemosynthesis and their role in gas cycling. Chemolithoautotrophy was studied at a time-series station during monthly (2007–2009) and seasonal cruises (January 2008, September 2008, January 2009) and was assessed in terms of the natural C isotopic ratio of particulate organic carbon (δ13POC), total and specific (associated with AAO and AMO) dark carbon assimilation (CA), and N2O and CH4 cycling experiments. At the oxycline, δ13POC averaged −22.2‰; this was significantly lighter compared to the surface (−19.7‰) and bottom layers (−20.7‰). Total integrated dark CA in the whole water column fluctuated between 19.4 and 2.924 mg C m−2 d−1, was higher during active upwelling, and contributed 0.7 to 49.7% of the total integrated autotrophic CA (photo plus chemoautotrophy), which ranged from 135 to 7.626 mg C m−2 d−1, and averaged 20.3% for the whole sampling period. Dark CA was reduced by 27 to 48% after adding a specific AAO inhibitor (ATU) and by 24 to 76% with GC7, a specific archaea inhibitor. This indicates that AAO and AMO microbes (most of them archaea) were performing dark CA through the oxidation of NH4+ and CH4. Net N2O cycling rates varied between 8.88 and 43 nM d−1, whereas net CH4 cycling rates ranged from −0.41 to −26.8 nM d−1. The addition of both ATU and GC7 reduced N2O accumulation and increased CH4 consumption, suggesting that AAO and AMO were responsible, in part, for the cycling of these gases. These findings show that chemically driven chemolithoautotrophy (with NH4+ and CH4 acting as electron donors) could be more important than previously thought in upwelling ecosystems, raising new questions concerning its relevance in the future ocean.

Tracer experiments ( 15 N and 13 C) were carried out off the Peruvian upwelling system in order to evaluate the potential role of regenerated nitrogen in sustaining biological productivity in surface waters (0–15 m depth range). Rates of daily carbon uptake in surface waters showed values ranging between 6 and 200 mg C m −3 d −1 . Maximum integrated rates were obtained in northern Peru (up to 5.5 g m −2 d −1 ). Parallel measurements of nitrogen uptake showed a stronger utilization of ammonium compared to nitrate at all stations, with surface ammonium uptake values reaching up to 0.15 μmol N L −1 d −1 . Ammonium was also actively regenerated in surface waters, at rates as high as 0.5 μmol N L −1 d −1 , whereas ammonium oxidation to nitrate (nitrification) occurred at lower rates ( −1 d −1 ). Results obtained in this study showed active regeneration of N within the euphotic layer. Regenerated nitrate and ammonium are, therefore, available for primary producers within the euphotic zone and sustain a fraction of the observed photoautotrophic carbon fixation. The contribution of nitrogen regenerating processes to primary production in terms of DIN could represent as much as 50% of NH 4 assimilated in surface waters (through ammonium regeneration) as well as a variable fraction (2–16%) of nitrate through nitrification.

Aerobic nitrite oxidation in marine environments plays a key role in the nitrification process. Marine bacteria involved in this nitrate-producing process have however been seldom studied compared with the ammonia-oxidizing community. Here, we report for the first time the community structure of aerobic nitrite-oxidizing bacteria (NOB) in the seasonal upwelling and oxygen-deficient area off Central Chile. Analysis of 16S rRNA by tag pyrosequencing was combined with specific quantitative polymerase chain reaction (qPCR) and reverse transcription qPCR in summer and wintertime. Nitrospina-like bacteria were the only known NOB detected by means of pyrosequencing between 30 and 80 m depth, accounting for up to 5% of total bacteria. This guild was represented by 11 and 7 operational taxonomic units (97% cut-off) in winter and summertime respectively. Nitrospina-like bacteria were phylogenetically related to sequences retrieved from coastal upwelling, oxygen minimum zones and deep-sea environments. This group was also detected by qPCR with abundances that increased with depth throughout the water column. Importantly, Nitrospina from surface layers showed low abundances but high 16S rRNA : rDNA ratios and mainly in summertime. Overall, our results highlight the seasonal variability between the structure and physiological state of this community and suggest a significant role of Nitrospina in the nitrogen cycle of seasonal upwelling areas.

The concentrations of greenhouse gases (GHGs), such as nitrous oxide (N2O) and methane (CH4), were measured in the Kerguelen Plateau region (KPR). The KPR is affected by an annual microalgal bloom caused by natural iron fertilization, and this may stimulate the microbes involved in GHG cycling. This study was carried out during the KEOPS 2 cruise during the austral spring of 2011. Oceanographic variables, including N2O and CH4, were sampled (from the surface to 500 m depth) in two transects along and across the KRP, the north–south (TNS) transect (46°–51° S, ~ 72° E) and the east–west (TEW) transect (66°–75° E, ~ 48.3° S), both associated with the presence of a plateau, polar front (PF) and other mesoscale features. The TEW presented N2O levels ranging from equilibrium (105%) to slightly supersaturated (120%) with respect to the atmosphere, whereas CH4 levels fluctuated dramatically, being highly supersaturated (120–970%) in areas close to the coastal waters of the Kerguelen Islands and in the PF. The TNS showed a more homogenous distribution for both gases, with N2O and CH4 levels ranging from 88 to 171% and 45 to 666% saturation, respectively. Surface CH4 peaked at southeastern stations of the KPR (A3 stations), where a phytoplankton bloom was observed. Both gases responded significantly, but in contrasting ways (CH4 accumulation and N2O depletion), to the patchy distribution of chlorophyll a. This seems to be associated to the supply of iron from various sources. Air–sea fluxes for N2O (from −10.5 to 8.65, mean 1.25 ± 4.04 μmol m−2 d−1) and for CH4 (from 0.32 to 38.1, mean 10.01 ± 9.97 μmol−2 d−1) indicated that the KPR is both a sink and a source for N2O, as well as a considerable and variable source of CH4. This appears to be associated with biological factors, as well as the transport of water masses enriched with Fe and CH4 from the coastal area of the Kerguelen Islands. These previously unreported results for the Southern Ocean suggest an intense microbial CH4 production in the study area.

Although the Southern Ocean is considered a High Nutrient Low Chlorophyll area (HNLC), massive and recurrent blooms are observed over and downstream the Kerguelen Plateau. This mosaic of blooms is triggered by a higher iron supply resulting from the interaction between the Antarctic Circumpolar Current and the local bathymetry. Net primary production, N-uptake (NO3− and NH4+), and nitrification rates were measured at 8 stations in austral spring 2011 (October–November) during the KEOPS2 cruise in the Kerguelen area. Iron fertilization stimulates primary production, with integrated net primary production and growth rates much higher in the fertilized areas (up to 315 mmol C m−2 d−1 and up to 0.31 d−1, respectively) compared to the HNLC reference site (12 mmol C m−2 d−1 and 0.06 d−1, respectively). Primary production is mainly sustained by nitrate uptake, with f ratio (corresponding to NO3− uptake/(NO3− uptake + NH4+ uptake)) lying in the upper end of the observations for the Southern Ocean (up to 0.9). Unexpectedly, we report unprecedented rates of nitrification (up to ~3 mmol C m−2 d−1, with ~90% of them