Unique Niche Research Articles

Designing platforms for digital object-based learning

Over the last decade, object-based learning programs have become a staple of museum collections. These programs encourage and allow patrons to engage with a series of curated objects, offering educational experiences through tactile exploration. Naturally, they are focused on having their audience engage with the physical objects themselves (Chatterjee & Hannan 2016). Applying museological practice and object-based learning in the digital context requires not just presenting digital replica of physical objects, but scaffolding their presentation and platform with purpose, intent, and understanding of the strengths and pitfalls of digital delivery (Beetham & Sharpe 2013; De Kluis, Romp, & Land-Zandstra 2024). As such, digital object-based learning platforms and programs purposefully designed for remote learning and online delivery fill a unique niche in the higher education space and are beginning to come into their own. At Macquarie University, objectbasedlearning.com (an initiative of the Faculty of Arts and stewarded by its Learning Design and Production team) was relaunched in late 2023 following an extensive redesign, with learning designers, academics, and students now working together to provide new remote learning opportunities and experiences for the classroom. This presentation introduces the audience to the refurbished website, explains the ethos behind its redesign with an eye to evolving learning spaces and remote learning, and explores the site’s current and future applications and projects as a case study for designing digital object-based learning. The site was designed with future utility and outreach at its core, offering flexibility in how it presents and categorizes digital objects, and a site layout which reflects the needs of its target audience – schoolteachers. The NSW Stages 5 and 6 Curriculum informs the website’s design, determining how objects are grouped, how users navigate the site, and what information and metadata is prioritized, developed, and displayed. Since its relaunch, the website has been utilized in schools and faculties in NSW to deliver object-based learning experiences and classes. While it is too early to publish on outcomes of the project, early feedback has been positive, and new teaching initiatives have developed around the platform. In 2024, student interns at Macquarie were challenged to develop educational materials, lessons, and workshops which took advantage of the potential of technology-enabled object-based learning. These artefacts were designed to give students a unique object-based learning experience, removing the boundaries of physical distance, financial constraints, and fragility of objects. Moreover, student interns involved in the photogrammetric scanning of objects for the website were themselves enjoying an object-based learning experience, engaging with their materiality and learning how best to present the object in a digital environment.

New insights on extramedullary granulopoiesis and neutrophil heterogeneity in the spleen and its importance in disease

Abstract Neutrophils are traditionally viewed as uncomplicated exterminators that arrive quickly at sites of infection, kill pathogens, and then expire. However, recent studies employing modern transcriptomics coupled with novel imaging modalities have discovered that neutrophils exhibit significant heterogeneity within organs and have complex functional roles ranging from tissue homeostasis to cancer and chronic pathologies. This has revised the view that neutrophils are simplistic butchers, and there has been a resurgent interest in neutrophils. The spleen was described as a granulopoietic organ more than 4 decades ago, and studies indicate that neutrophils are briefly retained in the spleen before returning to circulation after proliferation. Transcriptomic studies have discovered that splenic neutrophils are heterogeneous and distinct compared with those in blood. This suggests that a unique hematopoietic niche exists in the splenic microenvironment, i.e., capable of programming neutrophils in the spleen. During severe systemic inflammation with an increased need of neutrophils, the spleen can adapt by producing neutrophils through emergency granulopoiesis. In this review, we describe the structure and microanatomy of the spleen and examine how cells within the splenic microenvironment help to regulate splenic granulopoiesis. A focus is placed on exploring the increase in splenic granulopoiesis to meet host needs during infection and inflammation. Emerging technologies such as single-cell RNA sequencing, which provide valuable insight into splenic neutrophil development and heterogeneity, are also discussed. Finally, we examine how tumors subvert this natural pathway in the spleen to generate granulocytic suppressor cells to promote tumor growth.

Mechanisms of rhizosphere plant-microbe interactions: molecular insights into microbial colonization

The rhizosphere, as the “frontline” of plant life, connects plant roots, rhizosphere microorganisms, and surrounding soil, plays a crucial role in plant growth and health, particularly in sustainable agriculture. Despite the well-established contribution of plant-microbe interactions to plant health, the specific molecular mechanisms remain insufficiently understood. This review aims to summarize the physiological adjustments and signal modulation that both plants and microorganisms undergo within this unique ecological niche to ensure successful colonization. By analyzing key processes such as chemotaxis, root attachment, immune evasion, and biofilm formation, we uncover how plants precisely modulate root exudates to either recruit or repel specific microorganisms, thereby shaping their colonization patterns. These findings provide new insights into the complexity of plant-microbe interactions and suggest potential directions for future research in sustainable agriculture.

Dissecting the role of the HA1-226 leucine residue in the fitness and airborne transmission of an A(H9N2) avian influenza virus.

Although the capacity for human-like receptor binding is a key prerequisite for non-human origin influenza A virus (IAV) to become airborne transmissible in mammalian hosts, the underlying molecular basis is not well understood. In this study, we investigated a naturally occurring substitution (leucine to glutamine) at residue 226 in the HA of an avian-origin A(H9N2) virus and assessed the impact on virus replication and airborne transmission in the ferret model. We demonstrate that the enhanced airborne transmission associated with the HA1-L226 virus was mainly due to the increased infectivity of the virus. Interestingly, we found that, unlike most sites in the ferret respiratory tract, ferret ethmoid turbinate lined with olfactory epithelium favors replication of the AL/39-HA1-L226Q virus, suggesting that this site may serve as a unique niche for IAV with avian-like receptor binding specificity to potentially allow the virus to spread to extrapulmonary tissues and to facilitate adaptation of the virus to human hosts.

Community composition and seasonal dynamics of microplastic biota in the Eastern Mediterranean Sea

Marine plastic pollution poses a growing environmental threat, with microplastics accumulating in the global oceans. This study profiles the seasonal dynamics and taxonomic composition of the plastisphere, the microplastic ecosystem, in the Eastern Mediterranean Sea. Using long-read 16 S and 18 S metabarcoding, we analyzed offshore microplastic and whole seawater samples across each season over a two-year period. The analysis revealed a higher richness of prokaryotic communities on microplastics compared to seawater, which was predominantly composed of Proteobacteria and Bacteroidota and exhibited notable seasonal variability. Benthic eukaryotes were enriched on microplastics compared to the surrounding seawater. Diatoms (Bacillariophyceae), in particular, showed significant enrichment within the microplastic eukaryotic community with primarily pennate diatoms of Amphora, Navicula, and Nitzschia genera, whereas the seawater included mostly centric diatoms. Seasonal fluctuations were less pronounced in the microplastic communities than in seawater, highlighting the relative stability of this new human-made ecosystem. These findings underscore the unique ecological niche of microplastic-associated communities in marine environments.

Metabolomic profiling of in vitro and in situ grown Nilgiris tea reveals unique signatures for breeding decaffeinated varieties

This study was begun by establishing an in vitro culture in UPASI 9, a Nilgiris tea clone (Camellia sinensis) by optimising various factors. Anatomical studies demonstrated that use of lower carbendazim concentration for sterilisation (0.2%) produced viable and healthy explants for callus initiation. To confirm the genetic consistency of the regenerated plants, gene-specific SSR markers were developed and utilised. GC-MS was employed to analyse volatile metabolites extracted from callus, stem, micro shoots, and leaves of the UPASI 9 tea genotype. The results revealed distinct compositions of metabolites in each sample. More interestingly, caffeine was exclusively detected in leaf samples but absent in all other investigated tissues, despite the presence of Tea Caffeine Synthase (TCS) gene-specific SSRs. Thus, this study provided unique information on the absence of caffeine in in vitro grown Nilgiris tea clone, UPASI 9, as decaffeinated tea has a unique niche in the global market.

Adaptive traits of Nitrosocosmicus clade ammonia-oxidizing archaea.

Nitrification is a vital process within the global biogeochemical nitrogen cycle but plays a significant role in the eutrophication of aquatic ecosystems and the production of the greenhouse gas nitrous oxide (N2O) from industrial agriculture ecosystems. While various types of ammonia-oxidizing microorganisms play a critical role in the N cycle, ammonia-oxidizing archaea (AOA) are often the most abundant nitrifiers in natural environments. Members of the genus Nitrosocosmicus are one of the prevalent AOA groups detected in undisturbed terrestrial ecosystems and have previously been reported to possess a range of physiological characteristics that set their physiology apart from other AOA species. This study provides significant progress in understanding these unique physiological traits and their genetic drivers. Our results highlight how physiological studies based on comparative genomics-driven hypotheses can contribute to understanding the unique niche of Nitrosocosmicus AOA.

Efficient biodegradation of poly(butylene adipate-co-terephthalate) in mild temperature by cutinases derived from a marine fungus

Poly(butylene adipate-co-terephthalate) (PBAT) waste gradually accumulates in the environment, posing ecological risks. Enzymatic hydrolysis holds great potential in the end-of-life management of PBAT, but reported enzymes require high reaction temperatures, limiting their practical industrial applications. In this study, we discovered that the marine fungus Alternaria alternata FB1 can efficiently degrade PBAT at 28 °C. Two cutinases designated as AaCut4 and AaCut10, were identified and verified as key enzymes responsible for this degradation process. Notably, the recombinant AaCut10 was able to depolymerize 82.14 % PBAT within 24 h and fully decompose it within 48 h at 37 °C. Through protein engineering, the yield of terephthalic acid monomer was increased to 96.01 %, highlighting its potential for facilitating PBAT upcycling. Furthermore, based on the investigation of the distribution patterns of PBAT hydrolases, novel degradative agents have been identified within unique ecological niches, leading to the establishment of a comprehensive screening repository of PBAT hydrolases. Overall, our study provides new candidates for enzymatic PBAT recycling with low energy consumption and offers insights into the PBAT degradation manner in ecosystems.

Characterization of microbial communities in the sewage of a major urban drain

ABSTRACT Diverse bacterial assemblages were identified in a large, open stormwater drain (vernacular: nalah) built decades ago in a densely populated suburb of Delhi, India. Illumina-based next-generation sequencing (NGS) of 16S rRNA gene amplicons was conducted with metagenomic DNAs isolated from influent sewage water and sediment samples collected from Sahibabad drain, which now carries domestic and industrial wastes to downstream sewage treatment plants. Results are discussed with respect to diversity and adaptation to unique ecological niche(s) in these drains as well as the prevalence of potentially pathogenic bacteria. Recently, it has become a common practice to cover such drains with thick cement slabs to facilitate the construction of residential/commercial complexes. However, the impact of concrete covers on microbial communities that inhabit the Sahibabad drain is unknown. Results indicated that open drains with better aeration and exposure to sunlight contained microbes that likely enhance biodegradation in sewage water. The deposition of sediments along the course of the drain was dominated by methanogenic and sulphidogenic bacteria. Covering of the drain may have contributed to an increased abundance of anaerobic pathogens which settled in sediments and/or resuspended into sewage water. Such findings are important as the microbes active in sewage can impact public health and drain infrastructure.

Kenyans' perspectives on parenting roles and strategies used to raise young children in Kenya.

Research and parenting programs across the world emphasize two dimensions of parenting: warmth and control. Cross-country literature demonstrates many commonalities across samples on warmth; however, differences are evident with control, largely due to cultural and contextual nuances. Scant literature exists on parenting in Kenya, where half of Kenyans report experiencing child maltreatment typically by parents. Kenyan culture is a unique developmental niche important to understand and inform policies and parenting program development to reduce maltreatment. The purpose of this study was to understand perspectives on parenting strategies with young children, from a sample of Kenyans with varying experiences involving children (e.g., parents, community members). To our knowledge, this study is the first qualitative assessment of parenting practices among children under age 6 in Kenya. The 91 participants (62% female, all ≥ 18 years) completed interviews or focus groups. Based on a thematic data analysis, five themes emerged: (a) parental roles, (b) expressions of warmth, (c) cultural practices with children, (d) control strategies, and (e) factors impacting effective parenting. This study's findings have several implications for both informal and formal supports of families with young children. The findings offer insight into how Kenyans engage in parental warmth and control strategies, including those that are seen as culturally acceptable or harmful, and can inform the development or adaptation of parenting programs for Kenya. Furthermore, these findings offer important considerations for local and federal leaders in how to advance Kenya's policies and efforts to reduce childhood violence and promote healthy child development. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The integral co-management role of the medical pediatric urologist: Improving the care of children with urological conditions

The complexities of modern medicine prompt a re-evaluation of traditional patient care models to enhance safety and quality. We implemented a one-year pilot Medical Pediatric Urology fellowship, jointly developed by Urology and Pediatric Hospital Medicine, where a pediatrician received postgraduate training in both specialties. This innovative program aimed to augment knowledge and expertise in non-surgical aspects of pediatric urology. Upon completion of the fellowship, the trained pediatrician assumed the role of medical pediatric urologist (MPU), integrating into both Pediatrics and Urology faculties. Unlike the traditional specialist consultation model, the MPU became integral member of the Urology Division, working full-time and sharing responsibilities for both inpatient and outpatient pediatric urology care at a tertiary pediatric hospital in Canada. This study aims to delineate the training curriculum, role, clinical outcomes, and educational impact of the MPU over eight years. We retrospectively analyzed clinical outcomes, including patient volumes seen annually by MPU, urologists, and nurse practitioners from 2021 to 2023. Clinic wait times and patient satisfaction were compared between MPU's community and tertiary hospital pediatric urology clinics. Educational impact was assessed through pediatric residents' ratings for the MPU as a clinical teacher during urology rotations using a Likert scale. Integration of MPU led to the establishment of specialized clinics, including those for neurogenic bladder and posterior urethral valves. MPU accounted for approximately 34.7% of all outpatient clinic visits. Subjective feedback highlighted enhanced quality of care with MPU co-management in the inpatient setting. Additionally, in a community-based medical urology clinic (CUC) staffed by the MPU and a pediatric urology nurse practitioner, patients experienced shorter wait times and higher satisfaction (53±36 days and 194±108 days) (p<0.01), with 97% vs. 91% of families reported feeling highly satisfied with care (p<0.01) compared with hospital clinics, respectively. The MPU received ratings of 4/5 or 5/5 as a clinical teacher from 81.82% of pediatric residents. Our novel co-management approach in pediatric urology integrates medical and surgical expertise. However, limitations include the retrospective design and single-center setting. Nonetheless, this framework presents a potential model for other surgical specialties, offering a unique practice niche for trainees interested in the medical management of surgical conditions. The medical pediatric urologist plays a pivotal role as an educator, hospitalist, and director of the outpatient clinic, effectively integrating medical and surgical expertise. The MPU model is promising for optimizing safety and quality of care in pediatric urology.

Group B Streptococcus vaginal colonisation throughout pregnancy is associated with decreased Lactobacillus crispatus and increased Lactobacillus iners abundance in the vaginal microbial community.

Group B Streptococcus (GBS) asymptomatically colonises the vagina of up to 40% of pregnant women and can transmit to neonates during birth, causing neonatal pneumonia, sepsis, meningitis, and significant mortality. Vaginal GBS colonisation can be attributed to a range of host and bacterial factors, which may include the composition of the vaginal microbial community. There are few studies that have examined the vaginal community composition in relation to GBS colonisation throughout pregnancy. Here, we performed 16S rRNA sequencing (V3-V4) on vaginal swabs from women at 24- and 36-weeks' gestation, who were GBS culture-negative or GBS culture-positive at either 24 weeks or 36 weeks' gestation or at both timepoints. Vaginal swabs from 93 women were analysed; 46 women were culture-negative, 11 women GBS culture-positive at 24 weeks only, 21 women GBS culture-positive at 36 weeks only and 15 women GBS culture-positive at both timepoints on Brilliance GBS agar. V3-V4 16S rRNA gene amplicon sequencing demonstrated that in women that were GBS culture-positive at 36 weeks gestation only, G. vaginalis was significantly more abundant at 24-weeks' gestation despite a lack of significant changes in community richness between the 24- and 36-week samples. The vaginal microbial communities of women persistently colonised with GBS, had a significantly higher abundance of Lactobacillus iners, compared to other groups where L. crispatus, L. gasseri or L. jensenii were dominant. We have characterised the vaginal microbial community composition during pregnancy in relation to GBS colonisation status, in a longitudinal study for the first time. The most interesting finding was that in women that were persistently colonised with GBS throughout pregnancy, there was a significant increase in L. iners and significant reduction in L. crispatus abundance. Given the lack of detail of the role that the vaginal microbial community plays in GBS colonisation in the literature, it is imperative that the relationship between L. iners and GBS in this unique environmental niche is further investigated.

The Gut Microbiome of Two Wild Bumble Bee Species Native of South America: Bombus pauloensis and Bombus bellicosus

South America is populated by a wide range of bumble bee species that represent an important source of biodiversity, supporting pollination services in natural and agricultural ecosystems. These pollinators provide unique specific microbial niches, populated by a wide number of microorganisms such as symbionts, environmental opportunistic bacteria, and pathogens. Recently, it was demonstrated how microbial populations are shaped by trophic resources and environmental conditions but also by anthropogenic pressure, which strongly affects microbes’ functionality. This study is focused on the impact of different land uses (natural reserve, agroecosystem, and suburban) on the gut microbiome composition of two South American bumble bees, Bombus pauloensis and Bombus bellicosus. Gut microbial DNA extracted from collected bumble bees was sequenced on the Illumina MiSeq platform and correlated with land use. Nosema ceranae load was analyzed with qPCR and correlated with microbiome data. Significant differences in gut microbiome composition between the two wild bumble bee species were highlighted, with notable variations in α- and β-diversity across study sites. Bombus bellicosus showed a high abundance of Pseudomonas, a genus that includes environmental saprobes, and was found to be the second major taxa populating the gut microbiome, probably indicating the vulnerability of this host to environmental pollution. Pathogen analysis unveils a high prevalence of N. ceranae, with B. bellicosus showing higher susceptibility. Finally, Gilliamella exhibited a negative correlation with N. ceranae, suggesting a potential protective role of this commensal taxon. Our findings underscore the importance of considering microbial dynamics in pollinator conservation strategies, highlighting potential interactions between gut bacteria and pathogens in shaping bumble bee health.

Exploring the bacterial diversity of Dendrobium ovatum (L.) Kraenzl., a threatened orchid endemic to the Western Ghats of India: a preliminary report

ABSTRACT Dendrobium ovatum is an epiphytic orchid endemic to the Western Ghats of India. Due to its valuable medicinal and therapeutic properties, the plant has become extensively sought after, leading to its classification as ‘threatened’ in the latest research findings. The present study aims to identify the surface-associated and endophytic bacterial associates of Dendrobium ovatum, which may be of great significance from a conservation standpoint. The investigation resulted in isolating and identifying 21 bacterial isolates representing six genera from the absorption roots, stem, and leaves. Bacillus was the most dominant genus, with seven representative species from root and stem segments. Enterobacter formed the second most dominant genus, with four representatives from leaf and stem. Bacillus cereus was found to be the most prevalent species, with a relative frequency of 28.57%. Root segments were found to be the most diverse tissue compared to stem and leaves. The study concluded that each tissue represents a unique ecological niche harbouring specific bacterial associate. The study also illuminates the intricacies of the orchids’ microbial community structure and forms the first documentation of bacterial associates of the threatened endemic orchid D. ovatum.

Candidatus Thiothrix phosphatis SCUT-1: A novel polyphosphate-accumulating organism abundant in the enhanced biological phosphorus removal system

A novel coccus Thiothrix-related polyphosphate-accumulating organism (PAO) was enriched in an acetate-fed enhanced biological phosphorus removal (EBPR) system. High EBPR performance was achieved for an extended period (>100 days). A high-quality draft genome (completeness 97.2 %, contamination 3.26 %) was retrieved, representing a novel Thiothrix species (with similarity<93.2 % to known Thiothrix species), and was denoted as 'Candidatus Thiothrix phosphatis SCUT-1'. Its acetate uptake rate (6.20 mmol C/g VSS/h) surpassed most Ca. Accumulibacter and known glycogen-accumulating organisms (GAOs), conferring their predominance in the acetate-fed system. Metatranscriptomic analysis suggested that Ca. Thiothrix phosphatis SCUT-1 employed both low- and high-affinity pathways for acetate activation, and both the conventional (PhaABC) pathway and the fatty acid β-oxidation pathway for PHA synthesis; additionally, a much more efficient FAD-dependent malate: quinone oxidoreductase (MQO) were encoded and employed than the traditional malate dehydrogenase (MDH) to oxidize malate to oxaloacetate in the TCA and glyoxylate cycle, collectively contributing to a higher acetate utilization and processing rate of this microorganism. Batch tests further demonstrated the versatile ability of this PAO in using VFA (acetate, propionate, and butyrate), lactate, amino acids (aspartate and glutamate), and glucose as carbon sources for EBPR, showing a partially overlapped but unique ecological niche of this microorganism comparing to Ca. Accumulibacter and known GAOs. A metabolic model was built for Ca. Thiothrix phosphatis SCUT-1 using the above-mentioned carbon sources for EBPR. Overall, this study represents the first comprehensive characterization of the physiology and metabolic characteristics of representative coccus Thiothrix-related PAOs, which are expected to provide new insights into PAO microbiology in EBPR systems.

Dynamic responses of human lung innate and adaptive immune cells highlight the roles of genes at asthma risk loci.

The lung is a unique immunological niche with diverse immune cell types. The effects of stimulation through innate and adaptive immune receptors on human lung immune cells has largely been extrapolated from studies of blood immune cells. While multiple immune cell types and many genes have been implicated as contributing to asthma, the dynamics of these in human lung immune cells following activation will yield insights into asthma pathogenesis and lung immunity more broadly. Human lung immune cells from 6 donors were isolated. Mixed leukocytes were treated separately with lipopolysaccharide (LPS), F(ab)2-anti-human-IgM/IgG + IL4 and anti-CD3/CD28 for 4 and 18 hours and underwent single cell RNA sequencing (scRNAseq). Lung immune cell types were annotated, and gene expression compared across conditions. Genes at prior asthma-associated genetic loci were characterized across cell types, treatments and timepoints. Expression of non-classical class II genes associated with asthma, HLA-DQA2 and HLA-DQB2, and their protein products was characterized with immunohistochemistry. We characterized gene expression in 116,697 lung immune cells. Cell-, treatment-, and timepoint-specific effects on gene expression were detected in all lung immune cell populations. Correlation of gene expression between lung and blood lymphocyte populations decreased following stimulation. Among the genes that were differentially expressed, 97 receptor:ligand pairs had changes with treatments. 96.0% of genes at asthma risk loci demonstrated differential expression in at least one cell type and at least one treatment. B cells were the cell type with the highest expression of HLA-DQA2 and HLA-DQB2 which increased with anti-IgM/IgG treatment and the HLA-DQB2 protein was identified in lung B cells from a donor with asthma. Human lung immune activation elicits a broad range of cellular responses that deviate from those of blood immune cells and are relevant to asthma. Lung B cells expressing HLA-DQA2 and HLA-DQB2 appear to be involved in a novel antigen presentation pathway that contributes to asthma risk.

Morphological discrimination of fouling Ulva and Blidingia species on Pyropia rafts in Rudong, China: an in-field protocol for early monitoring of algae forming the Yellow Sea green tide

Abstract Fouling seaweeds on nori cultivation rafts in Subei radial sand ridges (Jiangsu, China) are believed to be the source of the Yellow Sea green tide (YSGT). Although major species are consistent across years, their biomass and proportions undergo significant annual changes, which was speculated to be related to the size of YSGT. Therefore, early detection and biomass assessment of the bloom-forming algae are crucial, increasing the need to develop a morphological identification method suitable for large sample sizes in the field. In this study, fouling seaweeds were collected from this area in spring 2017. Five major species, Ulva aragoënsis, Ulva compressa, Ulva linza, Ulva prolifera, and Blidingia sp. were molecularly identified, and confirmed as the predominant fouling seaweeds on nori rafts over the past decade. In this unique ecological niche, the morphological features of species changed significantly yet stably. Based on morphological observations, an identification key for these five species was established. Furthermore, a simplified version containing only two indices was developed for practical field use, with an average accuracy of 81 % (δ 2 = 0.003) in empirical accuracy assessments. This method can be used to monitor the community structure and succession of fouling seaweeds at the geographical source of YSGT.

Abstract B068: Human pancreatic cancer single cell atlas reveals association of CXCL10 positive fibroblasts and basal subtype tumor cells

Abstract Pancreatic ductal adenocarcinoma (PDAC) patients with tumors enriched for the basal-like molecular subtype exhibit severe resistance to standard of care treatments and have significantly worse overall survival, compared to patients with classical subtype enriched tumors. It is therefore important to develop resources that allow identification of novel targets in a statistically rigorous way to overcome therapeutic challenges. Here we compiled a single cell RNA sequencing (scRNAseq) atlas of the human pancreas with 229 individual patient samples, aggregated from raw data obtained from published studies. We mapped cell-type specific scRNAseq gene signatures in newly generated (n=12) and existing (n=13) spatial transcriptomics (ST) data from PDAC samples. Analysis of tumor cells from our scRNAseq atlas revealed nine transcriptionally distinct populations, two of which strongly align with a basal gene signature, correlating with worse overall survival in PDAC bulk RNAseq datasets. Deconvolution showed one of the basal populations identified to be the predominant tumor subtype in non- dissociated ST tissues and in vitro tumor cell and organoid PDAC lines. In bulk RNAseq datasets, we uncovered that myofibroblasts (myFb) expressing CXCL10 consistently correlated with both basal subtypes and were found near basal tumor cells using immunostaining. We also identified that besides immune cells, ductal cells also express CXCR3, the receptor for CXCL10, further suggesting a relationship between these cell types in PDAC tumor microenvironment (TME). Overall, we show that our newly built scRNAseq atlas, containing over 700,000 cells, integrated with ST data is a powerful resource, given that it corroborates numerous PDAC TME observations in the literature, with increased statistical power. Moreover, we uncovered a novel association between CXCL10+ myFb and basal tumor cells, underscoring the presence of unique spatial niches in PDAC that should be explored for the development of targeted therapies for this dismal disease. Citation Format: Ian M Loveless, Samantha B Kempt, Yuesong Wu, Daniel J Salas-Escabillas, Kailee Hartway, Madison George, Yetunde Makinwa, Thais Stockdale, Samuel D Zwernik, Kendyll Gartrelle, Rohit G Reddy, Daniel Long, Allison Wombell, Julie M Clark, Albert M Levin, David Kwon, Ling Huang, Ralph Francescone, Débora B Vendramini-Costa, Ben Stanger, Adam Alessio, Andrew M Waters, Yuehua Cui, Brian Theisen, Howard C Crawford, Nina G Steele. Human pancreatic cancer single cell atlas reveals association of CXCL10 positive fibroblasts and basal subtype tumor cells [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B068.

Differential interactions of Rickettsia species with tick microbiota in Rh. sanguineus and Rh. turanicus

Tick-borne rickettsioses, caused by Gram-negative bacteria of the Rickettsia genus, pose a growing global threat, with various arthropod vectors contributing to their transmission. Understanding the complex interactions within tick microbiota, including the role of Rickettsia species, is crucial for elucidating the dynamics of rickettsial diseases. Here, we investigate the taxonomic profiles and co-occurrence networks of Rickettsia in Rh. sanguineus sensus lato (s.l.) and Rh. turanicus ticks, revealing significant differences in community composition and local connectivity of Rickettsia species. While the microbiota of both tick species share common taxa, distinct differences in relative abundance and network topology suggest unique ecological niches. Moreover, robustness analysis demonstrates varying resilience to perturbations, indicating different strategies for network organization. Our findings also highlight metabolic differences between tick species, suggesting potential implications for Rickettsia interactions. Overall, this study provides insights into the intricate microbial landscape within ticks, shedding light on the functional redundancy and metabolic pathways associated with Rickettsia, thus advancing our understanding of tick-borne diseases.

Sensitivity of Alabama Freshwater Gastropod Species to Nickel Exposure.

Snails are effective bioindicators due to their prolific distribution, high level of endemism, and capacity to accumulate contaminants. Freshwater snails have unique ecological niches which are imperiled by land-use change and the introduction of hazardous chemicals. To assess how environmental alterations affect gastropods, lab-based studies are needed to characterize the toxicity of specific stressors. This can help guide policy decisions and remediation efforts. The aim of this research was to characterize acute toxicity of nickel (Ni) on endemic snails (Somatogyrus georgianus [Walker, 1904], Elimia cahawbensis [Lea, 1861], and Elimia spp.) and measure the accumulation of Ni and mineral elements including calcium (Ca), magnesium, potassium, and sodium (Na). Snails were exposed to six concentrations (25-800 µg/L) of Ni for 96 h. Among the studied snail species, E. cahawbensis was the most sensitive to Ni, with the lowest lethal concentration where 50% of the organisms died (LC50) at 88.88 µg/L Ni after 96 h. The LC50 at 96 h for S. georgianus was 167.78 µg/L Ni, and 393.13 μg/L Ni for Elimia spp. Except for Elimia spp., mortality of the other two snail species corresponded to the whole-body uptake of Ni. Nickel exposure also influenced Ca and Na uptake for Elimia spp. All three endemic species are potential candidate species for evaluating localized effects of human activities, and the present study provides a first step in characterizing how snails would be affected by environmental alterations. More research could further characterize potential effects of other human stressors on these endemic snail species. Future research into subindividual responses and routes of exposure can further elucidate variations in species sensitivity. Environ Toxicol Chem 2024;00:1-11. © 2024 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.