Early Settlement Research Articles

The role of Bifidobacterium genus in modulating the neonate microbiota: implications for antibiotic resistance acquisition in early life

ABSTRACT Resistance to antibiotics in newborns is a huge concern as their immune system is still developing, and infections and resistance acquisition in early life have short- and long-term consequences for their health. Bifidobacterium species are important commensals capable of dominating the infant gut microbiome and are known to be less prone to possess antimicrobial resistance genes than other taxa that may colonize infants. We aimed to study the association between Bifidobacterium-dominated infant gut microbiota and the antibiotic resistant gene load in neonates, and to ascertain the perinatal factors that may contribute to the antibiotic resistance acquisition. Two hundred infant fecal samples at 7 days and 1 month of age from the MAMI birth cohort were included in the study and for whom maternal-neonatal clinical records were available. Microbiota profiling was carried out by 16S rRNA amplicon sequencing, and targeted antibiotic resistance genes (ARGs) including tetM, tetW, tetO, blaTEM, blaSHV and ermB were quantified by qPCR. Infant microbiota clustered into two distinct groups according to their Bifidobacterium genus abundance: high and low. The main separation of groups or clusters at each time point was performed with an unsupervised non-linear algorithm of k-means partitioning to cluster data by time points based on Bifidobacterium genus relative abundance. Microbiota composition differed significantly between both groups, and specific bifidobacterial species were enriched in each cluster. Lower abundance of Bifidobacterium in the infant gut was associated with a higher load of antibiotic resistance genes. Our results highlight the relevance of Bifidobacterium genus in the early acquisition and establishment of antibiotic resistance in the gut. Further studies are needed to develop strategies to promote a healthy early colonization and fight against the spread of antibiotic resistances.

Effect of Rootstock Genotype and Arbuscular Mycorrhizal Fungal (AMF) Species on Early Colonization of Apple.

The effect of plant cultivar on the degree of mycorrhization and the benefits mediated by arbuscular mycorrhizal fungi (AMF) have been documented in many crops. In apple, a wide variety of rootstocks are commercially available; however, it is not clear whether some rootstock genotypes are more susceptible to mycorrhization than others and/or whether AMF species identity influences rootstock compatibility. This study addresses these questions by directly testing the ability/efficacy of four different AMF species (Rhizophagus irregularis, Septoglomus deserticola, Claroideoglomus claroideum or Claroideoglomus etunicatum) to colonize a variety of commercially available Geneva apple rootstock genotypes (G.11, G.41, G.210, G.969, and G.890). Briefly, micropropagated plantlets were inoculated with individual species of AMF or were not inoculated. The effects of the rootstock genotype/AMF interaction on mycorrhization, plant growth, and/or leaf nutrient concentrations were assessed. We found that both rootstock genotype and the identity of the AMF are significant sources of variation affecting the percentage of colonization. However, these factors largely operate independently in terms of the extent of root colonization. Among the AMF tested, C. etunicatum and R. irregularis represented the most compatible fungal partners, regardless of apple rootstock genotype. Among the rootstocks tested, semi-dwarfing rootstocks appeared to have an advantage over dwarfing rootstocks in regard to establishing and maintaining associations with AMF. Nutrient uptake and plant growth outcomes were also influenced in a rootstock genotype/AMF species-specific manner. Our findings suggest that matching host genetics with compatible AMF species has the potential to enhance agricultural practices in nursery and orchard systems.

Environmental conditions influencing the early colonization stage of Ludwigia hexapetala , an aquatic plant recently invasive in Italy

Freshwater ecosystems are among the most susceptible to biological invasions. The South American Ludwigia hexapetala is an aquatic plant that is becoming an increasing threat in many European waterbodies, recently including Italy. This study aimed to define the main parameters influencing the early colonization stage of L. hexapetala by overlapping the percentage cover of this species with environmental parameter data collected at 24 aquatic sites from six waterbodies in north-central Italy. At each site, chemical and physical characteristics of the water (temperature, pH, dissolved oxygen, conductivity, nitrates, phosphates, ammonia, depth, transparency), grain size of the substrate and level of anthropogenic disturbance were evaluated. The results showed that although L. hexapetala prefers shallow, warm, alkaline, moderately rich in ions and nutrients (especially phosphates) and oxygen-poor waters, it can grow in a wide range of environmental conditions. Moreover, as a typical invasive alien species, it spreads opportunistically in disturbed, unstable sites. Thus, L. hexapetala can invade freshwater habitats with different environmental conditions and subjected to anthropogenic disturbance. However, the results suggest that water depth may be a limiting factor in the early colonization stage of this species, which does not seem to be able to colonise waters deeper than 1 m in investigated sites, while it has been observed in significantly deeper waters in other European countries with a longer invasion history. Detecting the environmental parameters that most influence the growth of L. hexapetala becomes crucial both to identify the sites most at-risk of invasion in which to initiate timely monitoring actions for the species, and to be able to develop better management and control actions for this alien species in sites that have already been invaded.

Mechanics limits ecological diversity and promotes heterogeneity in confined bacterial communities

Multispecies bacterial populations often inhabit confined and densely packed environments where spatial competition determines the ecological diversity of the community. However, the role of mechanical interactions in shaping the ecology is still poorly understood. Here, we study a model system consisting of two populations of nonmotile Escherichia coli bacteria competing within open, monolayer microchannels. The competitive dynamics is observed to be biphasic: After seeding, either one strain rapidly fixates or both strains orient into spatially stratified, stable communities. We find that mechanical interactions with other cells and local spatial constraints influence the resulting community ecology in unexpected ways, severely limiting the overall diversity of the communities while simultaneously allowing for the establishment of stable, heterogeneous populations of bacteria displaying disparate growth rates. Surprisingly, the populations have a high probability of coexisting even when one strain has a significant growth advantage. A more coccus morphology is shown to provide a selective advantage, but agent-based simulations indicate this is due to hydrodynamic and adhesion effects within the microchannel and not from breaking of the nematic ordering. Our observations are qualitatively reproduced by a simple Pólya urn model, which suggests the generality of our findings for confined population dynamics and highlights the importance of early colonization conditions on the resulting diversity and ecology of bacterial communities. These results provide fundamental insights into the determinants of community diversity in dense confined ecosystems where spatial exclusion is central to competition as in organized biofilms or intestinal crypts.

Role of Volatile Organic Compounds Produced by Kosakonia cowanii Cp1 during Competitive Colonization Interaction against Pectobacterium aroidearum SM2.

The competitive colonization of bacteria on similar ecological niches has a significant impact during their establishment. The synthesis speeds of different chemical classes of molecules during early competitive colonization can reduce the number of competitors through metabolic effects. In this work, we demonstrate for the first time that Kosakonia cowanii Cp1 previously isolated from the seeds of Capsicum pubescens R. P. produced volatile organic compounds (VOCs) during competitive colonization against Pectobacterium aroidearum SM2, affecting soft rot symptoms in serrano chili (Capsicum annuum L.). The pathogen P. aroidearum SM2 was isolated from the fruits of C. annuum var. Serrano with soft rot symptoms. The genome of the SM2 strain carries a 5,037,920 bp chromosome with 51.46% G + C content and 4925 predicted protein-coding genes. It presents 12 genes encoding plant-cell-wall-degrading enzymes (PCDEWs), 139 genes involved in five types of secretion systems, and 16 genes related to invasion motility. Pathogenic essays showed soft rot symptoms in the fruits of C. annuum L., Solanum lycopersicum, and Physalis philadelphica and the tubers of Solanum tuberosum. During the growth phases of K. cowanii Cp1, a mix of VOCs was identified by means of HS-SPME-GC-MS. Of these compounds, 2,5-dimethyl-pyrazine showed bactericidal effects and synergy with acetoin during the competitive colonization of K. cowanii Cp1 to completely reduce soft rot symptoms. This work provides novel evidence grounding a better understanding of bacterial interactions during competitive colonization on plant tissue, where VOC synthesis is essential and has a high potential capacity to control pathogenic microorganisms in agricultural systems.

Substratifying the risk of covert malignancy in significant rectal polyps: Outcomes from a specialist multidisciplinary team (MDT).

A treatment strategy for patients with a significant polyp or early colon cancer (SPECC) of the rectum presents a challenge due to the significant rate of covert malignancy and lack of standardized assessment. For this reason, NICE recommends multidisciplinary meetings to improve outcomes. The primary aim of the present study was to report the performance of our specialist early rectal cancer (SERC) multidisciplinary team (MDT) in correctly substratifying the risk of cancer and to discuss the limitations of staging investigations in those patients with "poor outcomes". This was a retrospective review of patients referred to our SERC MDT from 2014 to 2019. Lesions were assigned by the MDT to three pre-resection categories (low, intermediate, high) according to the risk of covert malignancy. Resection method and final histology were compared to the pre-resection categories. Of 350 SPECC lesions, 174 were assessed as low-risk, 108 intermediate-risk and 68 high-risk. The cancer incidence was 4.8%, 8.3% and 53%, respectively (15.5% overall). Eight lesions were categorized as low-risk but following piecemeal resection were found to be malignant. Five lesions, three of which were categorized as high-risk, were ultimately benign following conventional surgery. One pT1sm1 cancer, removed by anterior resection, may have been treated by local excision. A total of 83% of malignant polyps were triaged to an en bloc resection technique and surgical resection avoided for nearly all benign lesions. However, 12 patients from this cohort were deemed to have a poor outcome because of miscategorization. Further comparative research is needed to establish the optimum strategy for rectal SPECC lesion assessment. There is currently no consensus for staging significant polyps of the rectum. This paper reports the effectiveness of a specialist early rectal cancer MDT to correctly risk-stratify significant rectal polyps. It underscores the importance of accurate categorization for treatment decision-making, while acknowledging the limitations of current staging modalities.

Renal potassium regulation in a pig model of therapeutic hypothermia

Therapeutic hypothermia is increasingly utilized clinically to reduce tissue metabolism and protect against neurological damage in cases of cardiac arrest, traumatic brain injury or perinatal hypoxic ischemia. With even mild exposure to hypothermia, hypokalemia develops purportedly due to transcellular potassium shifts resulting in decreased circulating potassium levels. Renal dysfunction with body temperature cooling has also been postulated to potentially contribute to development of sustained hypokalemia. In this study, we used a pig model of controlled acute hypothermia without confounding hypotension and hypoxemia, to test the hypothesis that renal handling of potassium remains intact in hypothermia and is not the cause of decreased circulating plasma potassium seen with body cooling. Anesthetized, mechanically ventilated Duroc cross young pigs (n=25, body weight = 10.0 ± 0.4 kg, male or female) were catheterized for hemodynamic monitoring, regional blood flow assessment via colored microspheres, and urine collection. After baseline values were obtained, pigs were divided into a control normothermia group (n=12) with body temperature maintained at 38.4 ± 0.1 oC or a hypothermia group (n=13) with core body temperature cooled to 34.5 ± 0.1 oC and hypothermia sustained for 2 hours. Hypothermia reduced tissue metabolism as indicated by a decrease in oxygen consumption (VO2= 5.2 ± 0.2 ml/kg in normothermia vs 3.7 ± 0.3 ml/kg in hypothermia. Mean arterial pressure (68± 3 mm Hg) and cardiac output (199 ± 21 ml/min/kg) were not different between groups. Even with the short duration of cold exposure, plasma potassium was lower (p<0.05) within 2 hours of hypothermia (4.1 ± 0.1 mEq/L) vs control (4.8 ± 0.1 mEq/L). Cold exposure caused redistribution of blood flow to the small intestines from other internal organs. Renal blood flow tended to decrease with cold, but glomerular filtration rate was suffcient to maintain urine flow, sodium excretion and free water clearance. Potassium clearance, however, was lower (p<0.05) in hypothermia (0.70 ± 0.07 ml/min/kg) than in normothermia (1.04 ± 0.07 ml/min/kg), with lower potassium excretion (hypothermia = 2997 ± 331 mEq/min vs control = 4784 ± 393 mEq/min, p<0.05) and fractional excretion of potassium. Reduced renal potassium excretion is consistent with renal compensation for lower circulating potassium induced by hypothermia. Interestingly, with relatively higher blood flow to the small intestines compared to decreased blood flow of other internal organs, potassium secretion in the early colon may contribute to further potassium wasting in hypothermia. The rapid initiation of decreased potassium circulating levels with hypothermia supports the thesis of temperature sensitive cell membrane potassium channels affecting extracellular to intracellular shifts of potassium. Results of this study indicate that renal potassium regulation is maintained in hypothermia and functions to decrease urinary potassium loss in the face of hypokalemia. The views expressed are those of the authors and do not necessarily reflect the offcial policy or position of the Defense Health Agency, Department of the Army, Department of Defense, or the U.S. Government. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The archaeology of shellfishing practices on Ua Huka, Marquesas Archipelago (French Polynesia)

AbstractShellfish remains are ubiquitous to coastal archaeological sites in the Marquesas but have seldom been the focus of dedicated investigations into their contribution to past diet and daily life. On the island of Ua Huka, in the northern group of the archipelago, people have consumed a variety of shellfish since their arrival on the island around the early 12th century AD. By analysing assemblages from five coastal sites spanning from the early settlement until the 18th century and using an archaeomalacological approach (precise taxonomic identification, coupled quantification methods, observation of taphonomic processes, biometry), we attempt to recount the exploitation processes of this resource, from the initial gathering stage to the final discarding of the shell. We further explore inter‐site and temporal variability in prey choice. Coupled with ethnographic accounts from European observers and insightful testimonies from current inhabitants of the island regarding present‐day practices, we highlight the persistence of choices regarding species selection, breakage patterns and cooking processes on an island that has seen major subsistence changes since European contact.

Aquatic macroinvertebrate community colonisation and succession in macadamia orchard and communal area reservoirs: a case study of Luvuvhu River valley, South Africa

The demand for macadamia nut production worldwide has led to increased use of pesticides and chemicals for pest and disease control. Reservoirs in these macadamia farming sectors are at . The current study investigated macroinvertebrate colonisation and succession associated with two macadamia orchards and two communal area reservoirs. The potential effects of stressors from these land uses was tested for and compared using stone substrates over a 6-week period. Stone substrates from both reservoir types were abundantly colonised over time and the total macroinvertebrate taxa and abundance showed an increasing trend across the sampled weeks, with macadamia orchards having the highest number of macroinvertebrate taxa. Strong ecological succession was observed across reservoirs, with the initial succession of early colonisers – i.e., Chironominae (, Ostracoda (and Anax sp. (predator) within communal area reservoirs, and Chironominae, Ostracoda Radix natalensis (scrapers) in macadamia orchard reservoirs – followed by predatory colonisers such as Gyrinidae larvae, Trithemis sp. (macadamia orchard reservoirs), and Ranatra sp. (communal area reservoirs). Macroinvertebrate community structure differed significantly across sites and weeks, with no similarity being observed for communities across the different reservoirs. Redundancy analyses further highlighted 11 sediment chemistry variables (i.e., pH, resistivity, P, K, Na, Ca, Mg, Cu, B, Fe and S) which were significantly related to macroinvertebrate community structure. Thus, sediment variables were found to be better predictors of macroinvertebrate community structure in macadamia orchard reservoirs than communal area reservoirs. Consequently, we concluded that differences in colonisation ability among taxa and environmental stressors were important factors driving succession. These results add to the understanding of the macroinvertebrate colonisation processes and environmental stressors within agricultural landscapes, which can aid in the development of conservation management of freshwater ecosystems.

Pre-Mamom Pottery Producers in the Heart of the Yucatan Peninsula

Recent research in the Maya Lowlands has revealed substantial new evidence for the first pottery producers at about 1000-600 bc, during the early Middle Preclassic period. This comparatively late adoption is a special case in Mesoamerica, where pottery appeared elsewhere up to a millennium earlier. Although archaic lifeways had long been established in the region, and pottery technology was likely known to some archaic communities, these new data reveal the complex set of circumstances that prompted the shift to ceramic production across the Yucatan Peninsula, Peten, and Belize. This article reviews these data from the perspective of the upland region of central and southern Yucatan, known as the Elevated Interior Region (EIR). Its rather complex early settlement links the EIR to contemporary pottery industries throughout the peninsula, suggesting well-established exchange systems were in place even as the first populations chose to settle more permanently on the landscape. Most significant among these cultural shifts was the increasing dependence on maize foodways as a primary subsistence strategy. Intensive maize agriculture has not been documented in Mesoamerica much before 1000 BC, yet ceramic technology was adopted independent of its use in other areas. Current evidence suggests, however, that the two were linked in the Maya Lowlands, where a relatively rapid transition took place as horticultural communities became more dependent on maize crops, followed waterways to settle more permanently on the landscape, and began producing pottery locally.

SNP‐based analysis of European Thymallus spp. (Salmonidae) reveals extensive mito‐nuclear discordance relevant for biogeographic inferences, taxonomy and conservation

AbstractAimPaleohydrological dynamics are well‐documented for European river systems, promoting shifting phases of isolation and connectivity of their aquatic fauna. These conditions coupled with high rates of hybridisation found in freshwater fishes may introduce considerable complexity and potential mito‐nuclear discordance of phylogenetic patterns. We evaluate this hypothesis using the first large‐scale analysis of nuclear SNPs in European species of grayling (Thymallus) compared to mtDNA data with the aim of reassessing the evolutionary history of this group of rheophilic fishes.LocationFreshwater systems in Europe.MethodsBased on mitochondrial (mitogenomes, control region) and nuclear (ddRADseq) data, we applied population‐genetic, phylogenetic, and biogeographic tools to evaluate lineage diversity in the context of paleohydrological alterations.ResultsThe results corroborated previously recognised high levels of lineage diversity, but revealed several cases of mito‐nuclear discordance and signals of both historical (natural) and human‐mediated introgression among major inter‐ and intraspecific lineages of Thymallus in Europe. A time‐calibrated phylogeny and ancestral area estimation, based on nuclear SNP data, supported a late Pliocene diversification of the genus in Europe and suggested an early colonisation of the Black Sea basin with subsequent dispersal into Central and Western Europe.Main ConclusionsThe genetic structure of Thymallus in Europe recovered by nuclear SNPs contrasts considerably with that supported by mtDNA. Several instances of mito‐nuclear discordance underscore frequent contact of allopatric lineages in a dynamic paleohydrological landscape and reveal the weakness of basing both taxonomic and conservation decisions on inferences based on mtDNA alone. The Danube and Rhine drainages were inferred as important zones of contact between divergent phylogeographic lineages. Additionally, our data cast doubt on the genetic integrity of the endangered T. aeliani. Its divergence from T. thymallus, using nuclear SNPs, appears minimal as samples of T. aeliani group within Danubian lineages, despite carrying highly divergent reciprocally monophyletic mtDNA.

Mass capture fishing in the Marquesas Islands

ABSTRACTMass capture of small fishes with a variety of nets, traps, and weirs was widely practiced and economically important across East Polynesia at western contact. Archaeological research, however, has suggested these technologies were less important during the early settlement period and gained prominence over time. Several explanations have been proposed, including resource depression, changes in marine environments, and/or social and economic reorientations. In the Marquesas Islands, pelagic and offshore fishes were historically well represented in early assemblages relative to most Polynesian islands. Here we report on fishbone assemblages from Nuku Hiva Island that were recovered with fine mesh screens, identified using a wide range of skeletal elements, and analysed with morphometric methods. The Hakaea Beach results demonstrate that mass capture of small fishes was especially important at this locality and sustained over three early, successive occupations. These patterns may reflect the nature of the local fisheries, preferential use of high‐return capture strategies in this reef‐limited setting, and/or purposeful avoidance of ciguatera‐prone fishes and a preference for less vulnerable fishes. Overall, our findings highlight geographic variation in early Marquesan fisheries and provide archaeological evidence that mass capture technologies had an important place in the maritime toolkits of the earliest East Polynesian fishers.

Historical analysis of timber exploitation in the Central Pacific Mountains of Costa Rica

Abstract [Introduction] The mountainous region of the Central Pacific of Costa Rica, currently made up mostly of the cantons of Turrubares, Puriscal and Mora, and to a lesser extent by the southwest of Acosta, was one of the most deforested areas since colonial times. [Objective] To comprehensively analyze the historical, socioeconomic, geo-climatic and ecological factors that possibly favored the logging exploitation of the forests of that region. [Methodology] The historical documents, and the geo-climatic, ecological and socioeconomic factors of the region were reviewed. In addition, a census was carried out among forestry professionals and industrialists to determine the timber species possibly extracted from the forests based on the floristic composition of protected forest areas in the region. [Results] The mountainous region was a transit and settlement site for Spanish colonists since the 16th century, which facilitated the development of access roads. Its proximity to the Central Valley, which needed forest and agricultural products for the growing urban area, together with the existence of an ecological convergence zone extraordinarily rich in trees of commercial importance, greatly facilitated the extraction of forest products. [Conclusion] The early colonization of the region, the existence of infrastructure, high demand for forest products at the national and international level, and the availability of forest resources in an area where the tropical dry forest, the cloud forest and the humid forest converge, and the edaphoclimatic conditions that also facilitated the development of agricultural crops, favored the change in land use and therefore the forestry exploitation of the region.

In vivo pilot study into superficial microcirculatory characteristics of colorectal adenomas using novel high-resolution magnifying endoscopy with blue laser imaging

BACKGROUND No studies have yet been conducted on changes in microcirculatory hemodynamics of colorectal adenomas in vivo under endoscopy. The microcirculation of the colorectal adenoma could be observed in vivo by a novel high-resolution magnification endoscopy with blue laser imaging (BLI), thus providing a new insight into the microcirculation of early colon tumors. AIM To observe the superficial microcirculation of colorectal adenomas using the novel magnifying colonoscope with BLI and quantitatively analyzed the changes in hemodynamic parameters. METHODS From October 2019 to January 2020, 11 patients were screened for colon adenomas with the novel high-resolution magnification endoscope with BLI. Video images were recorded and processed with Adobe Premiere, Adobe Photoshop and Image-pro Plus software. Four microcirculation parameters: Microcirculation vessel density (MVD), mean vessel width (MVW) with width standard deviation (WSD), and blood flow velocity (BFV), were calculated for adenomas and the surrounding normal mucosa. RESULTS A total of 16 adenomas were identified. Compared with the normal surrounding mucosa, the superficial vessel density in the adenomas was decreased (MVD: 0.95 ± 0.18 vs 1.17 ± 0.28 μm/μm2, P < 0.05). MVW (5.11 ± 1.19 vs 4.16 ± 0.76 μm, P < 0.05) and WSD (11.94 ± 3.44 vs 9.04 ± 3.74, P < 0.05) were both increased. BFV slowed in the adenomas (709.74 ± 213.28 vs 1256.51 ± 383.31 μm/s, P < 0.05). CONCLUSION The novel high-resolution magnification endoscope with BLI can be used for in vivo study of adenoma superficial microcirculation. Superficial vessel density was decreased, more irregular, with slower blood flow.

An effective method for preparing histological sections of blow fly intra-puparial stages for minimum PMI estimations

Blow flies (Diptera: Calliphoridae) are generally early colonisers of fresh cadavers, enabling the estimation of a minimum post-mortem interval (minPMI) based on an accurate aging of the oldest immature stages associated with a cadaver. In blow flies, the pupal stage and the subsequent development of the adult take place inside a protective case, the puparium, formed from the hardened and darkened cuticle of the third instar larva. Because the puparium is an opaque structure that shows virtually no external changes, qualitative analyses of the internal tissues can be very informative for determining reliable age-specific morphological markers. Those analyses can be performed using either non-invasive but expensive and not widely accessible techniques, or traditional histological methods, which are invasive as they require the serial sectioning of the sample. Histological methods are often readily available for forensic researchers and practitioners; however, the histological study of blow fly intra-puparial stages has traditionally been hampered by the poor paraffin infiltration of tissues due to the abundance of fat bodies, resulting in usually fragmented sections and the subsequent loss of relevant information. We present here an effective method for the preparation of histological sections of blow fly intra-puparial stages, maximising the paraffin infiltration while enabling the production of clean and entire sections that allow for the use of reliable age-specific morphological markers, thus improving the accuracy of minPMI estimations when access to more costly techniques is not feasible.

Abstract LB233: Single-cell transcriptional analysis of embryonic melanoblasts pinpoints embryonic cell states that underlie targeted therapy and immune checkpoint blockade resistance

Abstract Melanoma is a malignant neoplasia of pigment-producing melanocytes notable for its ability to metastasize early during primary tumor growth. Melanomas display typically high mutation burden—a hallmark associated with immune checkpoint blockade therapy (ICBT) sensitivity—but can still evade ICBT. These melanoma phenotypes likely relate to embryonic neural crest cells, a population of cells from which melanocytes arise. For instance, BRAF inhibition-evading melanoma cells adopt neural crest-like states. However, the exact embryonic lineage underlying BRAFi resistance remains unknown as does its relationship with any neural crest-like states that underlie ICBT resistance. To discover such states, we used a mouse fluorescent reporter model of melanoblast development in which melanocyte-specific GFP is driven by the dopachrome tautomerase promoter (iDct-GFP). Embryonic day (E) 11.5 and 15.5 melanoblasts were isolated and sequenced using single-cell transcriptomics (scRNA-seq). These time-points enriched for cells migrating from the dermis to epidermis (at E11.5) or for cells colonizing the hair follicle (at E15.5). These characteristics could help metastatic progression, namely migration across the basement membrane in early invasive melanomas and colonization of metastatic sites. We classified these embryonic melanocytes and their precursors into multiple clusters which in turn were grouped into four key lineages: Neural Progenitor, Schwann Cell Progenitor (SCP), Mesencyhmal (Mes) and Melanocytes (Mel). To detect the presence of these states in tumors, we derived developmental gene modules (DGMs): sets of genes that were preferentially co-expressed in each embryonic cell state. DGMs stratified TCGA samples; SCP-high and Mes-high subtypes were associated with worse survival compared to Mel-high tumors. Moreover, SCP-high tumors had lower T cell infiltration, and were associated with higher NGFR expression, a known marker of ICBT resistance. High expression of SCP DGMs was associated with poor response to anti-PD1 ICBT. Targeting factors underlying the SCP state might therefore sensitize tumours to ICBT. Mes DGMs on the other hand were associated with targeted therapy resistance. Cross-referencing DGMs with published RNA-seq data from melanoma cell lines suggest that SCP and Mes DGMs are induced by pro-inflammatory cytokines secreted by immune cells in the tumor microenvironment. Together, these observations suggest that the SCP state is implicated in the phenomenon of inflammation-induced de-differentiation, a process by which melanomas are able to evade ICBT. Our identification of the SCP and Mes states, along with a deeper understanding of their transcriptional programs and signaling pathways, may reveal clinically actionable targets to disrupt immuno- or targeted-therapy resistance. Citation Format: Vishaka Gopalan, Chun Wai Wong, Chi-Ping Day, Eva Perez-Guijarro, Maxwell P. Lee, Yuhong Jiang, Howard H. Yang, Maira Alves-Constantino, Antonella Sassano, Cari Smith, Mark Simpson, Sung Chin, Jessica Ebersole, Charli Gruen, Emily Wu, Sridhar Hannenhalli, Adam Hurlstone, Glenn Merlino, Kerrie Marie. Single-cell transcriptional analysis of embryonic melanoblasts pinpoints embryonic cell states that underlie targeted therapy and immune checkpoint blockade resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB233.

북한이탈주민 조기 정착을 위한 제도 개선 방안

North Korea under the socialist system has a structure in which the type and site of work are determined according to the central policy rather than employment other than individual ability in choosing jobs for its residents. Since it is important for North Korea, which is pursuing a planned economy, to achieve production goals set in accordance with each economic sector's plan, groups take precedence over individual abilities at the work site, and there are few changes in the working environment, such as turnover or relocation of work, so efforts or activities to equip individuals with competitiveness in their activities are of little significance. Most of the North Korean defectors who entered South Korea were subordinated in such a working environment at the time of their repatriation. South Korea is making great efforts to increase the competitiveness of individuals seeking employment because economic activities are determined according to the principle of marketism. North Korean defectors who were accustomed to the socialist planned economy system had jobs, but it is difficult to settle smoothly in that employment for adaptation to South Korean society is mainly achieved through competition with the general public. With 34,000 North Korean defectors now, their successful settlement in South Korean society as a priming water for the unification of the Korean Peninsula is drawing attention as a very important issue. This is because economic independence and income are achieved through employment, and the settlement of economic stability leads to stable participation in South Korean society. The economic activities of North Korean defectors will reduce the loss of social costs for them in South Korean society as a whole, which will further benefit the South Korean economy, and serve as a cornerstone for future unification of the two Koreas. Therefore, this study aims to suggest the possibility of obtaining compulsory employment-type qualifications in consideration of educational background and career in North Korea as an institutional improvement plan for early settlement based on economic stability in South Korea.

Intestinal microbiota modulates neuroinflammatory response and brain injury after neonatal hypoxia-ischemia

ABSTRACT Premature infants lack a normal intestinal microbial community and also at risk of perinatal hypoxic-ischemic (HI) brain injury, which is considered to be one of the major factors for motor, sensory, and cognitive deficits. We hypothesized that neonatal gut microbiota composition modulated the immune reaction and severity of neonatal H-I brain injury. Neonatal C57BL/6J mouse pups were exposed to H-I protocol consisting of permanent left carotid artery ligation, followed by 8% hypoxia for 60 min. Microbial manipulation groups included 1) antibiotic treatment, E18 (maternal) to P5; 2) antibiotic treatment E18 to P5 + E. coli gavage; 3) antibiotic treatment E18 to P5 + B. infantis gavage; and 4) saline to pups with dams getting fresh water. The extent of brain injury and recovery was measured on MRI. Edematous injury volume was significantly higher in E. coli group than that in B. infantis group and in fresh water group. Gene expression in brains of pro-inflammatory cytokines (IL1β, IL6, IL2, TNF-α and toll-like receptors 2–6) were elevated to a greater extent in the E. coli group at P10, no injury, and at P13, 72 hours after H-I relative to sham control and B. infantis groups. Significant effects of microbiome and brain injury and interaction of these factors were found in abundance of major phyla. The neuroinflammatory response and brain injury after neonatal hypoxia-ischemia are affected by intestinal microbiota, providing opportunities for therapeutic intervention through targeting the early colonization and development of the gut microbiota.

Abstract 1504: Tumor microenvironment-mediated regulation of early dissemination and colonization in breast cancer via BAZ2A-containing remodeling complexes

Abstract The molecular mechanisms governing invasion, dissemination, extravasation, and early metastatic colonization remain incompletely understood. In the BALB-neuT mouse model, we found that most metastases originate from disseminated cancer cells (DCCs) that left the primary site early in tumorigenesis, i.e. when lesions are still small. Consequently, we investigated whether cellular density and the tumor microenvironment synergize to generate the plasticity needed during metastasis. RNA-sequencing analyses of murine breast cancer cells in low cellular density (LD) and high cellular density (HD) conditions revealed distinct profiles of differentially expressed genes. Notably, we identified the enrichment of ribosomal RNA (rRNA) and chromatin remodeling pathways in LD conditions. Interestingly, once these cells were treated with Wnt4 and Rankl, factors secreted by the tumor microenvironment, the expression profile of genes involved in proliferation, migration and stemness as well as epigenetic-related factors changed drastically. Specifically, cells in LD conditions treated with Wnt4 and Rankl displayed induced migration and stemness phenotypes, whereas under HD conditions, these signals induced proliferation. Among the chromatin-remodeling pathways, we found that BAZ2A along with the rRNA regulating network were primarily upregulated in migratory cancer cells. Immunostaining of primary and metastatic lesions in murine and human breast cancer samples showed an upregulation of BAZ2A in early/microlesions compared to more advanced and proliferative macroscopic lesions. Taken together, these results indicate that cell density, tumor microenvironmental factors and BAZ2A-containing chromatin regulating complexes play pivotal roles in regulating cancer cell plasticity in breast cancer. Additional sequencing and functional analyses will be performed to dissect the specific components of this mechanism and evaluate their impact on the in vivo colonization of breast cancer models. Citation Format: Miriam Kokal-Ribaudo, Nora Jahnen, Saba Sameri, Fulvia Ferrazzi, Renato Liguori, Christoph A. Klein, Gernot Längst, Hedayatollah Hosseini. Tumor microenvironment-mediated regulation of early dissemination and colonization in breast cancer via BAZ2A-containing remodeling complexes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1504.

Identification of breadfruit (Artocarpus altilis) and South American crops introduced during early settlement of Rapa Nui (Easter Island), as revealed through starch analysis.

Starch residue analysis was carried out on stone tools recovered from the bottom layer of the Anakena site on Rapa Nui (Easter Island). These deposits have been dated to AD 1000-1300 AD and so far, represent the earliest evidence of human settlement on this island. Twenty obsidian tools were analyzed. Analysis of 46 starch grains recovered from 20 obsidian tools from the earliest dated level of the Anakena site on Rapa Nui provides direct evidence for translocation of traditional crop plants at initial stages of the colonization of this island. The analysis of starch grains was based mainly on statistical methods for species identification but was complemented by visual inspection in some cases. Our results identify taxons previously unknown to have been cultivated on the island, such as breadfruit (Artocarpus altilis), Zingiber officinale (ginger), and starch grains of the Spondias dulcis and Inocarpus fagifer tropical trees. Additionally, starch grains of Colocasia esculenta (taro) and Dioscorea sp. (yam), both common species in Pacific agriculture, were identified. Furthermore, the presence of four American taxa Ipomoea batatas (sweet potato), Canna sp. (achira), Manihot esculenta (manioc), and Xanthosoma sp., was detected. The occurrence of Canna sp., M. esculenta, and Xanthosoma sp. starch grains suggests the translocation of previously not described South American cultivars into the Pacific. The detection of I. batatas from this site in Rapa Nui constitutes the earliest record of this cultigen in the Pacific. Our study provides direct evidence for translocation of a set of traditional Polynesian and South American crop plants at the initial stages of colonization in Rapa Nui.