bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exploring new bacterial‐fungal interactions: the role of mannan degradation in Streptococci growth
Authors: Ticer Taylor , Fultz Robert , Glover Janiece , Engevik Melinda A. 
Published: May 2022

BackgroundStreptococci colonize multiple sites of the human body, including the oral cavity, nasopharynx, skin, respiratory, genitourinary and gastrointestinal tracts. At these various body sites, Streptococci not only interact with other microbes, but also with fungal organisms, such as Candida and Saccharomyces species. Several studies have identified an interaction between Streptococci and Candida species, but the details of these interactions are still being discovered and it is unclear if Candidaspecies can provide a nutrient source to support the growth of Streptococci. Candida and Saccharomyces species are covered by a polymer of mannose known as mannan. Mannan makes up the outermost layer of the fungal cell wall. A few gut microbes have been found to possess glycosyl hydrolases that degrade mannan, but the mannan‐degrading capacity of Streptococci has yet to be examined.HypothesisWe hypothesized that Streptococci that possess mannan‐degrading glycosyl hydrolases can enzymatically cleave mannose residues. We speculated that freed mannose residues could serve as a carbon source to promote Streptococci growth.Methods & ResultsUsing the Carbohydrate‐Active enZYme Database (CAZY) and Integrated Microbial Genomes (IMG) database, we analyzed the ability of 90 Streptococci genomes to transport and utilize mannose and to degrade diverse mannose‐linkages found on mannan. Our computational analysis identified that most Streptococci were able to transport mannose and drive glycolysis, but <50% of Streptococci harbored the glycosyl hydrolases required for mannan degradation. To confirm the ability of select Streptococci to degrade mannan, we grew 6 representative Streptococci in a chemically defined media lacking glucose supplemented with mannose, yeast extract or purified mannan isolated from Candida and Saccharomyces strains. Growth curve analysis revealed that all Streptococcus strains could use mannose to support growth. However, the ability to use yeast extract and mannan was strain specific. S. salivariusand S. agalactiae, which did not possess mannan‐degrading glycosyl hydrolases, could not use yeast extract or mannan to enhance their growth. In contrast, we found that S. mitis, S. parasanguinis, S. sanguinis, and S. pyogenes readily used yeast extract and isolated mannan for growth. Incubation with heat‐killed C. albicans confirmed the ability of mannan‐degrading strains to use intact mannan as a nutrient source.ConclusionsOur data indicates that select Streptococci with mannan degrading glycosyl hydrolases are capable of degrading fungal mannans and harvesting mannose for energy. These findings reveal a previously undescribed aspect of Streptococcal‐Candida interactions.
Studying the Impact of Annonaceous Acetogenin, A Prominent Component in Graviola Leaves, on the Growth of Glioblastoma Cancer Cells
Authors: Nusair Nisreen , Yoseph Hana 
Published: May 2022

Cancer is the second most common cause of death in the United States. In 2018, for every 100,000 people, 436 new cancer cases were reported and 149 people died of cancer. This research focuses on studying the impact of natural chemical compounds extracted from healthful food products, such as plant herbs on modulating cancer metabolism to potentially use these compounds as cancer therapeutic agents.This study investigates the effects of the natural chemical compound, Annonaceous Acetogenin (ACGs), that is a prominent component in the graviola plant leaves on the growth of glioblastoma cancer cells, U87MG. It is hypothesized that ACGs can reduce the growth of glioblastoma cancer cells.The presence of ACGs in the extract sample has been verified using the Matrix‐Assisted Laser Desorption/Ionization Time of Flight, also known as MALDI‐TOF. Then, extract samples with different concentrations of ACGs have been prepared and applied to glioblastoma cancer cells. Using the light microscope, images have shown that ACGs has significantly reduced the proliferation of glioblastoma cancer cells, when compared to the control samples. To confirm the results that have been observed in the images, a cell proliferation assay has been performed to detect the number of viable cells. In wells of a 96‐well plate, different concentrations of ACGs have been added to glioblastoma cancer cell samples. The absorbances at 490 nm were recorded using an ELISA plate reader. The results indicate a linear response between the cell number and absorbance at 490nm. The data suggests that as the amount of ACGs added to the cancer cells increases, the cell number (absorbance value) decreases.In conclusion, this research work suggests that ACGs, a prominent component in graviola leaves, can significantly reduce the growth of the glioblastoma cancer cells. Further investigations are necessary to examine how this natural chemical extract exhibits an anticancer effect and how it can potentially be used as a therapeutic agent against cancer.
Multi‐omics Analysis of S. Pneumoniae Extracellular Vesicles
Authors: Biedka Stephanie , Eutsey Rory , Hiller Luisa , Lucas Amber 
Published: May 2022

Extracellular vesicles (EVs) are cell‐derived nanoparticles that can serve as carriers of DNA, RNA, and protein. For the pathogen S. pneumoniae,which causes diseases such as pneumonia and meningitis, EVs can be used to transport these macromolecules to recipient cells, facilitating communication and signaling between cells. However, the overall composition of these S. pneumoniaeEVs is still unknown and how the macromolecules packaged within these EVs contribute to the pathogenicity of S. pneumoniaeremains a hot research topic. In this work, we have developed a novel multi‐omic workflow that isolates DNA, RNA and protein from a single S. pneumoniaeEV starting sample, enabling analysis of these macromolecules without the need for multiple sample preparation steps and allowing us to gain insights into the composition and functionality of S. pneumoniaeEVs.EVs from a S. pneumoniaeculture were isolated and the proteins in the EV homogenate were labeled with the bifunctional ProMTag. One end of the ProMTag forms a reversible, covalent bond with proteins. ProMTag’s other functional group is methyltetrazine, which forms an irreversible bond with trans‐Cyclooctene (TCO), allowing capture of EV proteins on TCO‐agarose beads. Organic solvent was then added to precipitate the nucleic acids in the EV homogenate. Nucleic acids were released by a series of washes and subsequently separated into DNA and RNA fractions by RNase or DNase treatment, respectively. Proteins were then released from the TCO‐agarose beads by reversing the ProMTag‐protein linkage, yielding proteins in their original, unmodified state ready for analysis. DNA and RNA were sequenced, and proteins were identified using mass spectrometry. Using this workflow, we were able to describe the composition of multiple macromolecules within S. pneumoniaeEVs and gain insights into how these macromolecules might facilitate communication and infection within the S. pneumoniaepopulation.
Hair‐Bearing Human Skin Organoids from Pluripotent Stem Cells: A Novel Source of Advanced Skin Substitutes for Wound Repair
Authors: Sheets Anthony R. , Deakin CiCi , Lee Jiyoon , Koehler Karl R. 
Published: May 2022

Cutaneous injuries represent a major clinical challenge domestically and globally. Indeed, chronic wounds are estimated to affect the quality of life of nearly 2.5% of the United States population, and diabetic foot ulcers have a lethality nearly equivalent to that of all cancers combined. While skin grafts remain an important component in the care of both acute and non‐healing wounds alike, there are numerous drawbacks to such procedures, including lack of acceptable donor sites, morbidity associated with harvest, potential scarring at recipient sites, and graft loss. To these ends, advanced skin substitutes have been developed in efforts to overcome some of these obstacles, however existing modalities combining dermal and epidermal cell populations fail to develop skin appendages like eccrine glands and hair follicles critical for normal skin function. Thus, there is an unmet need for advanced cellular skin substitutes that more faithfully recapitulate native human integument.Our recent work reveals that co‐induction of epithelial and mesenchymal cell differentiation from human pluripotent stem cells gives rise to hair‐bearing skin organoids (SKOs) in vitro. These SKOs develop as spherical structures composed of mesenchymal cells surrounding stratified keratinocytes lining a central cystic cavity, producing hair follicles with bulbs oriented radially outward and hairs that grow into the cyst. Importantly, hairy human SKOs successfully engraft when applied to small incisions surgically created on the backs of immunocompromised nude mice, transitioning to a planar orientation with vertical hair outgrowth within 4‐5 weeks of transplant. Therefore, we hypothesized SKOs could similarly be applied to excisional wounds in a model system more akin to human injuries requiring skin grafts.Here, we demonstrate that hairy human SKOs applied to murine dorsal excisional wounds at 140 days post‐differentiation successfully take and undergo cystic‐to‐planar transition (CPT) within 5 weeks of surgery. We further show that SKOs xenografted at 80 days post‐differentiation, when hair‐germ‐like buds are visible in vitro but have not yet sprouted hairs, not only readily engraft and go through CPT, but also continue to develop hairs in vivothat show vertical outgrowth within the same time frame. Moreover, human SKOs xenografted at an earlier stage of development appear less macroscopically distinct from the surrounding host mouse skin than those at the later, hair‐bearing stage, suggesting transplant at earlier time points may yield improved cosmetic outcomes. Overall, our findings reveal human pluripotent stem‐cell derived SKOs may form the basis of a novel advanced skin substitute for clinical use, with future studies focused on exploring their utility in additional models of both acute and chronic wounds, as well as understanding the molecular and cellular mechanisms underlying CPT.
Implementing Ungrading in Undergraduate Exercise Physiology
Authors: Stenson Mary 
Published: May 2022

Natural science faculty are increasingly experimenting with alternate modes to assess student learning. Ungrading, popularized by Susan Blum’s edited anthology of the same name, gives instructors freedom to move beyond traditional grades for a more complete understanding of student learning. Ungrading is a student‐centered approach to assessment of learning which focuses on student self‐reflection and metacognition, and limiting instructor bias. Ungrading can be useful in physiology education by incentivizing intrinsic motivation and attention to understanding instead of memorization. Reducing grade anxiety allows students in exercise physiology to focus on understanding and applying course content.In spring 2020, ungrading was implemented in an upper division undergraduate exercise physiology course taught over 4 weeks (N=19). In previous sections, students often commented that their grade did not reflect how much they learned. The purpose of ungrading was to more closely align grades with student learning. The lecture portion of the course occurred as a flipped classroom with small group meetings. In class, students asked and answered questions, discussed primary research, and interpreted physiological data to better understand and apply course material. Students were given details about ungrading at the beginning of the course, read selected essays about ungrading, and discussed their impressions of the new system with the instructor. One student had previous experience with ungrading.Students completed two guided self‐evaluations to describe their learning and reflect on their challenges and successes. Twice during the course students met individually with the instructor to receive feedback about their self‐evaluations and overall performance. During the mid‐term meeting, students set specific goals to work towards for the remainder of the course.Student self‐reflections (n=19) and student opinion surveys (n=15) were used to evaluate the ungrading practice. 89.4% (n=17) of the students indicated they agreed or strongly agreed that their learning was enhanced by ungrading. 100% of students agreed or strongly agreed that they valued their learning during the course. 87% (n=13 of 15) indicated the amount they learned in the course was excellent or good. 93% (n=14 of 15) rated the evaluative techniques and grading as excellent or good. Qualitative analysis of open‐ended reflection questions revealed students felt they were more easily able to apply knowledge with less grade based anxiety. Students reported increased curiosity and a deeper understanding of content when revising mistakes or misconceptions in their work. The instructor found ungrading very effective in improving student engagement with and understanding of course content. Overall, ungrading was effective for encouraging a deeper understanding of course content and aligning course grades with student learning.
The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Plays an Important Role in Fetal Human Colon Cell Migration and Proliferation
Authors: Mogan Cara A. , Grant Garett J. , LeBaron Kaylee , Liou Theodore G. , Helms My N. 
Published: May 2022

Background‐Cystic Fibrosis (CF) is an inherited genetic disorder resulting from mutations in the gene encoding cystic fibrosis transmembrane conductance regulator (CFTR). For reasons that are not completely clear, CF patients over the age of 40 are 4‐8 times more likely to develop colon cancer than the general population. Moreover, positive history of distal intestinal obstruction syndrome or organ transplant further increase risk of developing colon cancer by 11‐fold.Objective‐The objective of this research is to test the hypothesis that inherited CFTR mutations in CF patients promote colon cancer development by increasing cell migration and proliferation via altered epidermal growth factor (EGFR) signaling.Methods‐Scratch assays were performed on confluent fetal human colon epithelial cells (FHC) and the rate of cell migration was measured 1‐5 days after treatment with either CFTR activating (IBMX and forskolin) or inhibiting compounds (CFTRinh‐172 and CFTR siRNA). Ki67 nuclear antigen and EGFR labeling were conducted using standard immuno‐histochemical labeling and detection techniques.Results‐We found that both pharmacological and siRNA inhibition of CFTR activity increased the rate of wound closure and cell migration. Conversely, IBMX and forskolin stimulation of CFTR decreased the rate of FHC migration (vs untreated control rates). Inhibition of CFTR also associated with increased levels of Ki67 (a classic cell proliferation marker) and increased expression of EGFR (which has known roles in cell growth and differentiation).Conclusion‐Our results indicate that CFTR plays an important role in FHC colon cell migration and EGFR signaling, which could lead to a better understanding as to why CF patients have increased risk for colon cancer.
The influence of body size and phylogeny on trabecular microstructure in the proximal femur and humerus of rodents and primates
Authors: Peters Kara D. , Kuo Sharon , Ryan Timothy M. 
Published: May 2022

Life history theory states that organisms maximize their fitness via energetic trade‐offs between various biological functions. It has been well‐established that life history strategy is related to intraspecific variation in body size and that body size predicts some bone microstructural properties, but the relationship between life history strategy and skeletal variation has not been sufficiently examined across multiple mammalian clades. Generally, small‐bodied mammals have “fast” life histories and faster growth rates than large‐bodied mammals, meaning small mammals deposit bone tissue at a faster rate, which may affect skeletal morphology. Therefore, the goal of this study was to conduct a preliminary analysis of trabecular bone structure in the rodent and primate humerus and femur to evaluate the influence of life history traits, particularly body size, on bone properties in a phylogenetically diverse sample. Using a sample of 67 size‐matched adult rodent and primate individuals from 8 extant rodent genera (N=26) and 10 extant primate genera (N=41) ranging in body size from 0.04kg to 70kg, we analyzed trabecular bone structure in the proximal femoral and humeral head. Regression analyses were used to assess associations between trabecular bone properties and body size and one‐way ANOVAs were used to compare bone properties between rodents and primates across three size‐matched classes.Regression results are consistent with previous primate and mammal studies. Bone volume fraction (BV/TV) scales with weak positive allometry in both groups and both elements except for the rodent humerus, which scales isometrically. Degree of anisotropy (DA) varies across all groups and shows no consistent relationship with body size. Trabecular thickness (Tb.Th) and trabecular separation (Tb.Sp) increase with body size, while connectivity density (Conn.D) and bone surface density (BS/BV) decrease with body size across both clades and elements. In both groups and both bones, Tb.Th, Tb.Sp, and Conn.D scale with strong negative allometry while BS/BV scales with strong positive allometry. ANOVAs reveal that Tb.Th and Tb.Sp are higher in the primate femur than in the rodent femur for medium and large size classes, while Conn. D is higher in the rodent femur for medium and large size classes. Other bone properties do not show consistent patterns of differences between primates and rodents. Overall, while overlapping confidence intervals for all slopes suggest body size scales similarly with these bone properties across clades, ANOVA results suggest that medium and large bodied rodents have thinner, more numerous trabeculae in the femur compared to similarly‐sized primates. Further investigation is necessary to elucidate the biological significance of this result and the underlying mechanisms driving the observed phenomenon.
LPS‐induced endotoxemia promotes blood‐brain barrier permeability via TSP1‐dependent TGFβ1 activation
Authors: Bhattarai Shadikchhya M. , Frampton Gabriel , Jhawer Ashwin , Troyanovskaya Eleonora , McMillin Matthew 
Published: May 2022

IntroductionDuring disease states, the blood‐brain barrier (BBB) can become permeable due to endothelial injury or dysregulation of tight junction proteins. Endotoxemia, which induces systemic inflammation, causes BBB dysfunction and neuroinflammation. We have shown that transforming growth factor beta 1 (TGFβ1) is upregulated during systemic inflammation and promotes BBB permeability by disrupting claudin‐5 and occludin. Therefore, we hypothesize that TGFβ1 is upregulated during endotoxemia and induces BBB permeability by disrupting tight junction proteins.MethodsC57Bl/6 mice were administered 3 mg/kg of LPS and monitored for neurological decline. In a second set of mice 6 hours after LPS administration, an antagonist to TGFβ1 activation, LSKL, or control, SLLK, were injected (1 mg/kg/ip). Mice were euthanized 24 hours after LPS injection and tissue was collected. In a subset of animals, 3 hours prior to euthanasia, Evans Blue was injected (8%/ip) to assess BBB function. TGFβ1, claudin‐5, occludin, IL‐1β, IL6 and TNFα expression was assessed by RTPCR, immunoblotting and immunofluorescence. In vitro studies using mouse brain endothelial cells (bEnd.3 cells) were treated with LPS (10 μg/ml) or rTSP1 (1 μg/ml) to activate TGFβ1. TGFβ1, TSP1, claudin‐5 and occludin expression was assessed by immunofluorescence or RTPCR. Barrier function was determined in bEnd.3 cell monolayers using TEER or 10‐kDa FITC‐dextran diffusion. Data were analyzed using GraphPad Prism with results presented as mean +/‐ SEM. Differences between two groups were compared using Student’s t‐test and differences between three groups were determined using ANOVA.ResultsTGFβ1 expression was increased in cortex and cerebellum of LPS‐treated mice. This was associated with decreased claudin‐5 and occludin mRNA expression and immunofluorescence staining. Treatment of bEnd.3 cells with LPS increased TGFβ1 and TSP1 expression, decreased TEER, and increased FITC‐dextran diffusion. Supplementation of bEnd.3 cells with rTSP1 led to decreased claudin‐5 and occludin mRNA expression, decreased TEER, and increased FITC‐dextran diffusion across the transwell. LSKL treatment in LPS‐treated mice reduced sickness behavior, reduced Evan’s blue penetrance into the brain, restored tight junction expression and alleviated neuroinflammation when compared to SLLK‐treated mice.ConclusionsStrategies to target TGFβ1 signaling may prove effective at alleviating endotoxin‐induced BBB dysfunction.
Cutaneous Microvascular Responses to Local Heating on Ventral and Dorsal Aspects of the Forearm
Authors: Patik Jordan C. , Shoemaker Leena N. , Wenner Megan M. , Edwards David G. 
Published: May 2022

The cutaneous microvasculature is considered a representative vascular bed and is regularly used to interrogate the mechanisms of microvascular function in healthy and diseased humans. For instance, cutaneous dilation in response to local heating can provide an index of nitric oxide (NO) bioavailability. While the skin of the forearm is typically used for local heating studies, some studies have used the ventral forearm while others have used the dorsal forearm skin for this assessment. Since the dorsal aspect of the forearm typically has more hair and receives greater sun exposure than the ventral side, there is speculation that cutaneous dilation may differ from one side of the forearm to the other, in magnitude and/or mechanism. As such, studies utilizing different sides of the forearm may not be comparable. Therefore, we aimed to test the hypothesis that cutaneous local heating responses differ between the ventral and dorsal aspects of the forearm in response to the two most common temperature stimuli, 39°C and 42°C.MethodsTen young, normotensive individuals (6 men/4 women, age: 26 ± 2 years) were studied on two separate occasions separated by 2‐7 days. At each visit, 4 intradermal microdialysis fibers were placed in either the ventral or dorsal forearm, in a random order. Two fibers were perfused with Ringer’s solution to serve as control sites and the other 2 fibers were perfused with 10 mM N(G)‐Nitro‐L‐arginine methyl ester (L‐NAME) to inhibit NO synthase. Red blood cell flux (RBCF) was assessed at all sites via laser Doppler flowmetry. Each pair of sites (control and L‐NAME) was heated to either 39°C or 42°C for ~40‐45 min until RBCF plateaued. All sites were then infused with 28 mM sodium nitroprusside and heated to 43°C to establish maximal RBCF. Cutaneous vascular conductance (CVC) was calculated as RBCF / mean arterial pressure measured during the plateau and maximal phases. Plateau results are reported as a percentage of maximal CVC at each respective site. The relative NO contribution is reported as: [(control plateau – L‐NAME plateau)/control plateau] x 100.ResultsNo differences were observed at the control site between ventral and dorsal aspects of the forearm when heated to 39°C (62 ± 13 vs. 62 ± 16 % CVCmax, P=0.99). Likewise, the heating response to 42°C was similar across the forearm (ventral: 90 ± 9 vs. dorsal: 86 ± 12% CVCmax, P=0.21). The relative contribution of NO to the plateau was comparable across the forearm at 39°C (ventral: 70 ± 20 vs. dorsal: 66 ± 21%, P=0.71) and 42°C (ventral: 63 ± 16 vs. dorsal: 69 ± 11%, P=0.11).DiscussionThese preliminary findings suggest that cutaneous vasodilation elicited by local heating is similar on both sides of the forearm at both 39°C and 42 °C. Additionally, it appears that the relative contribution of NO to local heating‐induced microvascular vasodilation is not different across the forearm.