South America Research Articles

Phytopathogenic Fungi and Their Active Metabolites With Bioherbicidal Potential Against the Invasive Alligator Weed, Alternanthera philoxeroides

ABSTRACTAlligator weed (Alternanthera philoxeroides), originally from South America, is a notorious semi‐aquatic invasive species in many countries, including India. Due to its amphibious nature, it not only damages the aquatic environment but is also detrimental to the terrestrial ecosystem. To seek an environmentally sound control option for alligator weed, this study focused on selecting an appropriate mycoherbicidal agent. A series of steps from field survey‐based collection, isolation and selection of promising fungal strains, followed by host range determination to biocontrol potential studies against the weed were undertaken. Twenty‐three phytopathogenic fungi were isolated, and among these, the fungi with the highest herbicidal activity (> 90% disease severity) were subjected to morphological and molecular characterisation and identified as Alternaria alternantherae (= Nimbya alternanthera). The fungus and its crude metabolites were tested against 76 plant species, showing a relatively narrow host range. This fungal species is being reported from West Bengal, India, for the first time. Although the fungus has been considered as a potential biocontrol tool against alligator weed in countries such as Australia, Brazil and China, long‐term, detailed research for A. alternantherae and its active metabolites to be developed as bioherbicides against alligator weed remains indispensable.

Structural dynamics of the TPR domain of the peroxisomal cargo receptor Pex5 in Trypanosoma

Peroxisomal protein import has been identified as a valid target in trypanosomiases, an important health threat in Central and South America. The importomer is built of multiple peroxins (Pex) and structural characterization of these proteins facilitates rational inhibitor development. We report crystal structures of the Trypanosoma brucei and T. cruzi tetratricopeptide repeat domain (TPR) of the cytoplasmic peroxisomal targeting signal 1 (PTS1) receptor Pex5. The structure of the TPR domain of TbPex5 represents an apo-form of the receptor which, together with the previously determined structure of the complex of TbPex5 TPR and PTS1 demonstrate significant receptor dynamics associated with signal peptide recognition. The structure of the complex of TPR domain of TcPex5 with PTS1 provided in this study details the molecular interactions that guide signal peptide recognition at the atomic level in the pathogenic species currently perceived as the most relevant among Trypanosoma. Small – angle X – ray scattering (SAXS) data obtained in solution supports the crystallographic findings on the compaction of the TPR domains of TbPex5 and TcPex5 upon interaction with the cargo.

Reaching new lands: Updating the distribution of Angiostrongylus cantonensis in South America with the first record in Argentina.

Angiostrongylus cantonensis, commonly known as the rat lungworm, is a metastrongyloid nematode found primarily not only in tropical and subtropical regions but also in temperate areas and considered the leading cause of eosinophilic meningitis in humans. Synanthropic rodents such as Rattus norvegicus and Rattus rattus are the most frequent definitive hosts of this parasite. The presence of this parasite was detected in the pulmonary arteries of three specimens of R. norvegicus in the city of Buenos Aires representing the species' southernmost known record in natural hosts. Species confirmation was achieved through partial sequences of 18S and COI genes. By comparing the COI gene sequences with those available in GenBank through the construction of a haplotype network, we obtained that the analysed specimen presents high similarity with those reported in Japan and Southeast Asia. All infected rats were captured in an area surrounding a port with significant import and export activity, suggesting that A. cantonensis may have been introduced through commercial ships. Specifically, the parasite was detected in a neighbourhood with vulnerable socio-economic conditions and in a nature reserve, which exhibit biotic and abiotic characteristics conducive to sustaining high-density rat populations, scattered waste, areas of spontaneous vegetation, debris accumulation and flooded areas or lagoons offering suitable habitats for intermediate hosts such as snails. Thus, the close proximity of the port to these sites creates a favourable ecological context for the establishment of A. cantonensis. This study shows the need to conduct research to detect A. cantonensis in non-endemic areas but with the characteristics that promote its arrival and development of its life cycle in order to implement control measures to prevent expansion of this parasite and its transmission to humans and other animals.

A new “silesaurid” from the oldest dinosauromorph-bearing beds of South America provides insights into the early evolution of bird-line archosaurs

Investigations regarding the early evolutionary history of bird-line archosaurs have undergone significant advancements in recent years. However, controversies remain, especially regarding the phylogenetic position of “silesaurids”. Whereas some hypotheses place these archosaurs as the sister-group to dinosaurs, others suggest that “silesaurids” are early ornithischian dinosaurs. Despite the phylogenetic disputes, “silesaurids” are a crucial group for comprehending the origins and early evolution of dinosaurs. In the present study, a new “silesaurid” from the Middle-Upper Triassic of Southern Brazil is described. Gondwanax paraisensis gen. et sp. nov. comes from the Dinodontosaurus Assemblage Zone of the Santa Maria Formation (Ladinian-Carnian boundary), representing one of the oldest “silesaurids” worldwide. Furthermore, Gondwanax paraisensis gen. et sp. nov is the oldest “silesaurid” with three sacral vertebrae, a feature usually observed in more derived forms. In addition, distinct from any other Triassic Pan-Aves, the new taxon bears an incipient fourth trochanter of the femur. This unique combination of features indicates a high diversity of locomotor strategies among early pan-avians. The co-occurrence of Gondwanax paraisensis gen. et sp. nov. and Gamatavus antiquus in the same Assemblage Zone represents the oldest evidence of sympatry among “silesaurids” in South America. Indeed, the unique combination of sacral and hindlimb features may suggest distinct behaviors for these species, potentially leading to niche differentiation within the same ecosystems.

Neuropsychological assessments of older adults in Overseas France (French Guiana and Réunion Island) and South America (Brazil)

Neuropsychological assessments of older adults in Overseas France (French Guiana and Réunion Island) and South America (Brazil)

The Disappearance of Traditions: The Use of Geographical Indications and Collective Marks to Prevent Loss of Culture in South America

The Disappearance of Traditions: The Use of Geographical Indications and Collective Marks to Prevent Loss of Culture in South America

680. P02.06 MATTERHORN PCR BY REGION

Abstract Background FLOT was established as a perioperative therapy for GC/GEJC following the Phase 2/3 FLOT4 study conducted in Germany, with a pCR rate of 16% (Al-Batran et al, Lancet Oncol 2016). The global MATTERHORN study (NCT04592913) showed a statistically significant improvement in pCR with perioperative D+FLOT vs placebo (P) + FLOT in GC/GEJC at first interim analysis (Janjigian et al, ESMO Congress 2023). Subgroup analyses by region and country were completed to assess pCR rates with FLOT and benefit of D+FLOT across the global study population. Methods Participants (pts) with resectable GC/GEJC were randomized 1:1 to D 1500 mg or P every 4 weeks (Q4W) on Day 1 plus FLOT Q2W on Days 1 and 15 for 4 cycles (2 doses of D or P and 4 doses of FLOT pre- and post-operative), followed by D 1500 mg or P on Day 1 Q4W for 10 further cycles. Randomization was stratified by Asia vs non-Asia. pCR (Modified Ryan; central review) was assessed in prespecified (Asia) and post hoc regional subgroups, including 6 countries with the highest numbers of randomized pts. Results Of 948 pts randomized globally, 180 (19%) were in Asia. pCR outcomes with FLOT in Asia were consistent with global outcomes. pCR rates were improved with D+FLOT vs P+FLOT in all regions (Asia, Europe, North America and South America; Table), despite some imbalances in baseline characteristics and numerical differences in pCR rates by geographic location. The pCR rate with P+FLOT in the German subgroup (13%; 95% CI, 6.1–23.0) was similar to that with FLOT in the FLOT4 study. Improvement in pCR with D+FLOT vs P+FLOT was observed across subgroups by country. Similar trends across regional subgroups were observed for combined complete and near-complete response rate. Conclusions In MATTERHORN, pCR was consistently improved with the addition of D to perioperative FLOT in GC/GEJC across geographic regions. The study is ongoing for the primary objective of event-free survival.

Influence of the October 14, 2023, Ring of Fire Annular Eclipse on the Ionosphere: A Comparison Between GNSS Observations and SAMI3 Model Prediction

AbstractCelestial phenomena such as solar eclipses disrupt the ionosphere's inherent photochemical, dynamic, and electrodynamic processes and can be viewed as a natural experiment that provides a unique opportunity to study ionospheric perturbations. We investigate the spatiotemporal ionospheric response induced by the 14 October 2023 annular eclipse using ground‐based Global Navigation Satellite System (GNSS) receivers located over the continental region of North and South America. The largest total electron content (TEC) change (∼22 TECU decrease) is observed over the path of the eclipse at around 16°–18°N which lies just before the greatest eclipse location. However, the percentage change in TEC here is ∼44% (of the background value), which is less than that observed at midlatitudes around 30°–35°N (∼18.7 TECU, ∼50%). We observed a latitudinal dependency of TEC variation and time delay in ionospheric response to the eclipse with midlatitudes experiencing greater TEC changes and longer time delays compared to low‐latitude and equatorial regions. The SAMI3 model used to simulate the impact of the eclipse, captures the large decrease in VTEC along the eclipse path. Interestingly, increases in the TEC are also observed in several GNSS sites and it varied from 4.5 to 6.5 TECU in the Northern Hemisphere and 7 to 12 TECU in the Southern Hemisphere. The SAMI3 model results also show an enhancement in TEC but significantly less than that observed. Moreover, the SAMI3 model simulations for individual GNSS site coordinates within the conjugate regions failed to predict accurately, the TEC enhancement recorded by the GNSS sites.

Unveiling the Enigma of Molar Incisor Hypomineralisation: Causes, Consequences and Management Strategies

Abstract Molar incisor hypomineralisation (MIH) is a defect in the development of tooth enamel, affecting permanent first molars and incisors. This article explores MIH causes, consequences and management strategies for dental professionals. MIH is widespread, ranging from 2.4% to 40.2% globally. South America has the highest prevalence, while Africa has the lowest. Clinically, MIH presents as demarcated white, yellow or brownish opacities on the enamel surface. Affected teeth are fragile and prone to chipping, hypersensitivity and caries. MIH disrupts the tooth’s structure, increasing the risk of fractures, dentin exposure, pulp inflammation and rapid tooth decay. It can also lead to poor oral hygiene, aesthetic concerns and reduced quality of life for children. The causes of MIH are multifactorial and involve systemic or environmental factors during pre-natal or post-natal tooth development. Potential factors include childhood illnesses, antibiotic use, environmental toxins and Vitamin D deficiency. Early diagnosis and intervention are crucial for MIH management. Treatment options depend on the severity of the condition and may involve remineralisation, desensitisation, fluoride therapy, pit and fissure sealants, restorations or extractions. MIH is a common dental concern in children. Early management by dental professionals can help prevent complications and improve oral health outcomes.

Prevalence of Listeria monocytogenes in Milk and Dairy Product Supply Chains: A Global Systematic Review and Meta-analysis.

Listeria monocytogenes, one of the main foodborne pathogens, is commonly found in milk and dairy products. This study aimed to estimate the presence of L. monocytogenes in milk and dairy product supply chains using a meta-analysis based on PubMed, Embase, Web of Science, and Scopus databases. A total of 173 studies were included in this meta-analysis. The pooled prevalence in the supply chain environment was 8.69% (95% confidence interval [CI]: 5.30%-12.78%), which was higher than that in dairy products (4.60%, 95% CI: 1.72%-8.60%) and milk products (2.93%, 95% CI: 2.14%-3.82%). Subgroup analysis showed that L. monocytogenes prevalence in raw milk (3.44%, 95% CI: 2.61%-4.28%) was significantly higher than in pasteurized milk (0.60%, 95% CI: 0.00%-2.06%). The highest prevalence of L. monocytogenes in milk and dairy products was observed in North America (5.27%, 95% CI: 2.19%-8.35%) and South America (13.54%, 95% CI: 3.71%-23.37%). In addition, studies using culture and molecular methods (5.17%, 95% CI: 2.29%-8.06%) had higher prevalence than other detection methods. Serogroup 1/2a and 3a (45.34%, 95% CI: 28.74%-62.37%), serogroup 1/2b and 3b (14.23%, 95% CI: 6.05%-24.24%), and serogroup 4b/4e (13.71%, 95% CI: 6.18%-22.83%) were dominant in these studies. The results of this study provide a better understanding of the prevalence of L. monocytogenes in milk and dairy product supply chains and suggest a potential foodborne pathogen burden.

On the Role of Physical Processes in Controlling Equatorial Plasma Bubble Morphology

AbstractIn this study, we present the results of an analysis of the morphological features of Equatorial Plasma Bubbles (EPBs) over South America. In this context, we analyzed data from the Disturbance Ionosphere indeX (DIX) maps calculated using around 450 Global Navigation Satellite System (GNSS) stations. To mitigate the influence of magnetic disturbances on bubble development, only data from geomagnetically quiet days were utilized. This study covered the period from the post‐peak of solar cycle 24 (2015) to the pre‐peak of solar cycle 25 (2023), totaling 1321 nights with EPB occurrences, representing the largest data set of EPBs ever compiled for South America. Our analysis unveiled several key findings regarding EPBs and their behavior over the South American region. First, we observed that the amplitude of plasma depletions, as reflected in the DIX values, and the EPB latitudinal development follow an approximately 11‐year cycle driven by solar radiation levels. Furthermore, our analysis highlights the significant influence of factors such as the angle between the solar terminator and the magnetic meridian (T‐M angle), which varies inversely with the vertical plasma drift velocity during the pre‐reversal enhancement (PRE). Additionally, we discuss the longitudinal variations associated with magnetic declination, as well as the saturation behavior of EPB development with extreme solar flux.

Molecular Epidemiology of Western Equine Encephalitis Virus, South America, 2023-2024.

Western equine encephalitis virus (WEEV) is a mosquitoborne virus that reemerged in December 2023 in Argentina and Uruguay, causing a major outbreak. We investigated the outbreak using epidemiologic, entomological, and genomic analyses, focusing on WEEV circulation near the Argentina‒Uruguay border in Rio Grande do Sul state, Brazil. During November 2023‒April 2024, the outbreak in Argentina and Uruguay resulted in 217 human cases, 12 of which were fatal, and 2,548 equine cases. We determined cases on the basis of laboratory and clinical epidemiologic criteria. We characterized 3 fatal equine cases caused by a novel WEEV lineage identified through a nearly complete coding sequence analysis, which we propose as lineage C. Our findings highlight the importance of continued surveillance and equine vaccination to control future WEEV outbreaks in South America.

Rmg10, a Novel Wheat Blast Resistance Gene Derived from Aegilops tauschii.

Wheat blast, caused by Pyricularia oryzae (syn. Magnaporthe oryzae) pathotype Triticum (MoT), is a devastating disease that can result in up to 100% yield loss in affected fields. To find new resistance genes against wheat blast, we screened 199 accessions of Aegilops tauschii, the D genome progenitor of common wheat (Triticum aestivum), by seedling inoculation assays with Brazilian MoT isolate Br48 and found 14 resistant accessions. A synthetic hexaploid wheat line (Ldn/KU-2097) derived from a cross between the T. turgidum 'Langdon' (Ldn) and resistant A. tauschii accession KU-2097 exhibited resistance in seedlings and spikes against Br48. In an F2 population derived from 'Chinese Spring' × Ldn/KU-2097, resistant and susceptible individuals segregated in a 3:1 ratio, suggesting that the resistance from KU-2097 is controlled by a single dominant gene. We designated this gene Rmg10. Genetic mapping using an F2:3 population from the same cross mapped the RMG10 locus to the short arm of chromosome 2D. Rmg10 was ineffective against Bangladesh isolates but effective against Brazilian isolates. Field tests in Bolivia showed increased spike resistance in a synthetic octaploid wheat line produced from a cross between common wheat cultivar 'Gladius' and KU-2097. These results suggest that Rmg10 would be beneficial in farmers' fields in South America.

Addressing Technology-Assisted Child Sexual Abuse During an Initial Clinical Assessment: A modified Delphi Study.

Technology-assisted child sexual abuse (TA-CSA) is defined as any type of sexual abuse with an online element occurring under the age of 18. The literature suggests that victims often experience difficulty in finding support that adequately addresses the online elements of TA-CSA. Research also suggests that practitioners are unsure about how to best approach TA-CSA during initial assessments. This modified Delphi study with healthcare professionals and researchers as experts was conducted to understand best practice principles on how to approach the topic of TA-CSA when a young person presents to clinical services. An online, two round modified Delphi study was completed. Round 1 consisited of statements generated from existing published TA-CSA literature. One hundred and twelve participants were invited to complete Round 1. Twenty-four participants responded to Round 1, and of those responders, 15 completed Round 2. All healthcare professionals (10) and eight researchers were located in the United Kingdom. The remaining researchers were based in North and South America, Australia and Europe. Participants agreed that there is a need to provide practitioners with guidance on how to approach TA-CSA and that asking general questions about online life can help ease into the topic of TA-CSA. Additionally, a clear multi-agency approach and adequate training can provide practitioners confidence in their ability in managing risk and disclosure of TA-CSA. This study provides important initial findings in approaching TA-CSA within an initial assessment. However, future research is necessary in understanding the transferability of these findings to clinical settings.

The only terrestrial lineage in the Branchiopoda redefined: a new species of Bryospilus Frey, 1980 (Cladocera: Anomopoda) from India and adaptations of waterfleas to life on land

Abstract Only a small proportion of the world’s crustacean taxa is adapted to limno-terrestrial microhabitats that are disconnected from conventional surface waterbodies. In rare occasions, water films on terrestrial tropical and subtropical vegetation may also harbour specialised cladocerans. Bryospilus Frey, 1980 (Chydoridae) is the only genus within the class Branchiopoda that is specialised to living almost exclusively in water-saturated terrestrial moss patches, leaf litter, and phytotelms. The remarkable waterflea lineage, which has a suite of highly unusual characters within the family, has been found in terrestrial habitats in rainforests of West Africa, South and Central America, and New Zealand. We discovered a new moss-inhabiting chydorid from western India, Bryospilus (Indobryospilus) bharaticus n. sp., the first representative of the genus from the Oriental Region. Its morphology and behaviour are highly unusual for a species of Bryospilus. In comparison to its congeners, the new species can swim and it has significantly less oligomerisation, with three terminal setae on the antennal endopod instead of two and seven exopod setae on the third limb instead of six, among other features. We define a new subgenus Indobryospilus nov. and we amend the genus Bryospilus. The new species is a living evolutionary connection, characterised by a phenotype which provides us with new clues about evolutionary transitions in the only terrestrial branchiopod genus. Our results are informative beyond Cladocera, as the morphology of this species provides insights about the evolution and parallelisms of aquatic crustaceans that have specialised in limno-terrestrial habitats. We revisit the morphology of the genus, the disjunct biogeographical pattern with a potential ancient signature, and discuss the functional adaptations of these cladocerans to life on land, as well as convergences with subterranean lineages. A new key to the world species of Bryospilus species is included.

225 Perceptions of Physical Activity and Structured Exercise in South Carolinian Adult Native Americans

225 Perceptions of Physical Activity and Structured Exercise in South Carolinian Adult Native Americans

Stakeholder Insights: A Socio-Agronomic Study on Varietal Innovation Adoption, Preferences, and Sustainability in the Arracacha Crop (Arracacia xanthorrhiza B.)

Arracacha, a root crop indigenous to the Andean region of South America, holds significant agronomic and socio-economic importance in Colombia. The study aims to evaluate the impacts of adopting the ‘Agrosavia La 22’ variety on agricultural sustainability and productivity, encompassing economic, environmental, and social dimensions. Additionally, it analyzes the preferences of farmers and other stakeholders regarding the sustainability of the introduced technological innovations. Conducted over three years (2021–2023), the study offers comprehensive insights into adoption trends and stakeholder perceptions. Utilizing the Ambitec-Agro methodology, the research assesses the environmental, social, and economic impacts of ‘Agrosavia La 22’. Data collection involved field observations and interviews with farmers and key actors in the arracacha supply chain. Results indicate a substantial increase in the cultivated area from 1500 hectares in 2021 to 2650 hectares in 2023, with the proportion of total cultivated area rising from 47.6% to 84.1%. Economically, ‘Agrosavia La 22’ demonstrated significant input cost savings, reducing costs by USD 347 per hectare by 2023 and enhancing producer surplus from USD 30.95 to USD 651.16 per hectare. Yield comparisons show higher median yields for ‘Agrosavia La 22’ (20 t ha−1 in 2023) compared to traditional varieties (12.5 t ha−1). Socially, there was a marked improvement in farmers’ income perceptions, and environmentally, there was a reduction in greenhouse gas emissions (324.05 kg CO2-eq ha−1) due to optimized fertilizer and pesticide applications. Eco-efficiency (EE) analysis shows that ‘Agrosavia La 22’ consistently demonstrated positive EE values, indicating economic viability alongside lower GHG emissions. In 2021, its EE stood at 2.2 USD/kg CO2-eq, increasing to 27.75 USD/kg CO2-eq by 2023, reflecting substantial economic gains relative to environmental impact. Conversely, the traditional variety initially exhibited lower EE due to high GHG emissions. Challenges such as soil quality decline and market price volatility were noted. Overall, the findings underscore the economic, social, and environmental benefits of ‘Agrosavia La 22’. Furthermore, the methodology used in this study can be applied to the evaluation of other varietal innovations in developing countries with limited resources for assessing agricultural technology impacts.

New records of the Non-native Amazon sailfin catfish Pterygoplichthys pardalis (Castelnau, 1985) in Bangka Island Indonesia

Abstract The freshwater species known as Pterygoplichthys pardalis (Castelnau, 1985), commonly referred to as the Sailfin catfish, is native to temperate and tropical regions of South America, with a particular prevalence in the Amazon. Due to insufficient regulation of the pet fish industry, certain species from this family have been inadvertently or deliberately introduced to various places worldwide. In Indonesia, the occurrence of the sailfin catfish has been recorded in the natural freshwater habitats of Java and Sumatra. The introduction of non-indigenous fish species into natural aquatic environments has had adverse effects on biodiversity due to factors such as competition for resources, modification of habitats, and transfer of diseases so the presence of the P. pardalis is a danger alert. This study presents the first evidence of the presence of the sailfin catfish P. pardalis on Bangka Island, located in the western region of Indonesia. During the field trip conducted in August 2023, a total of twenty specimens were obtained from the Rangkui River, Pangkal Pinang.

Research on longevity and associated age data of South American anurans: trends, gaps and recommendations

Longevity is one of the most important characteristics in the life history of organisms. It is directly associated with growth, reproduction and age of sexual maturity. Despite this, little is known about longevity in South American anuran species, a region considered as a hotspot of world diversity. Thus, we carried out a literature review of publications on longevity of South American anurans that used the skeletochronology method to identify the main publication trends, as well as to point out the main information gaps and suggest future directions. We found clear biases when we analysed temporal, spatial and taxonomic patterns in publications on longevity: (i) studies are recent (mostly from 2015 onwards), (ii) bufonids and leptodactylids were the most studied groups, (iii) medium to large species are the most studied, (iv) species with wide geographic distribution, low risk of extinction, (v) the studies are concentrated in Brazil and Argentina, and (vi) most studies are in the Chaco biogeographical sub-region. We suggest that future work prioritizes little explored families and with high species diversity, small-bodied species, with restricted distribution, threatened with extinction, in order to expand the representation of different evolutionary lineages along the biogeographical units of South America.

Climate‐Driven Projections of Future Global Wetlands Extent

AbstractWetlands are crucial components of the Earth's system, interacting with various processes such as the hydrological cycle, energy exchanges with the atmosphere, and global nitrogen and carbon cycles. The future trajectory of wetlands is anticipated to be influenced not only by direct human activities, but also by climate change. Here we present our assessment of climate‐driven global changes in wetlands extent, focusing on the main wetland complexes. We used an approach based on the Topographic Hydrological model (TOPMODEL) and soil liquid water content projections from 14 models of the Coupled Model Intercomparison Project Phase 6 (CMIP6). Our analysis reveals a consistent decrease in wetlands extent in the Mediterranean, Central America, and northern South America, with a substantial loss of 28% in the western Amazon Basin for the end of the 21st century (2081–2100) under the SSP370 scenario. Conversely, Central Africa exhibits an increase in wetlands extent, except in the Congo Basin. Nevertheless, most of the areas studied (80%) present uncertain results, due to conflicting projections of changes between the models. Notably, we show that there is significant uncertainty among CMIP6 models regarding liquid soil water content in high latitudes. By narrowing our focus to 10 models, which seem to better represent the thawing of permafrost, we obtain a better inter‐model agreement. We then find a modest declines in the overall global area (<5%), but an average loss of 13% beyond 50°N. Specific areas like the Hudson Bay Lowlands experiencing a 21% decrease and the Western Siberian Lowlands a 15% decrease.