Fecal Pellets Research Articles

Progressive Gut Microbiome Dysbiosis Is Associated with Chronic Lymphocytic Leukemia Pathogenesis and Development in the Eµ-TCL1 Mouse Model

Introduction: The gut microbiome is home to a community of microorganisms such as bacteria, fungi, viruses, archaea, and protozoa. Maintaining a balance between “favorable” and “unfavorable” bacteria within the gut microbiome is essential for homeostatic physiological processes including proper immune system development, regulation of metabolic pathways, protection against pathogens, and gut epithelium integrity. Chronic lymphocytic leukemia (CLL) is a mature B-cell malignancy characterized by the accumulation of CD5 + B-cells in the blood, bone marrow, and secondary lymphoid tissues. The pathogenesis of CLL is related to the activation of critical survival pathways such as B-cell and toll-like receptor signaling pathways, where microbial antigens are known to be key stimulators driving CLL B-cell proliferation. In this study, we investigated how the gut microbiota composition contributes and correlates to CLL disease progression. Methods: Using a well-established murine model representative of CLL development in humans, we profiled the gut microbiota of transgenic Eµ-TCL1 mice and age-matched wild-type B6 (WT B6) mice over the course of 12 months (n = 7-10/group). Fecal pellets were collected aseptically from study mice at four time points (4, 7, 10, and 12 months) for DNA extraction using the QIAamp® PowerFecal® Pro DNA Kit. To characterize the gut microflora, we utilized 16S rRNA sequencing using the Illumina 16S metagenomics protocol. Bacterial taxonomy was assigned and analyzed using the QIIME2™ platform. Linear Discriminant Analysis (LDA) Effect Size (LEfSe) analysis was employed to identify differentially expressed bacterial taxa between cohorts. Beta diversity indices were used to evaluate intersample differences in the fecal microbiota. Mice were monitored for peripheral expansion of leukemia cells (%CD45 +/CD19 +/CD5 + cells) via flow cytometry. Next, we evaluated the microbiome in an aggressive model of CLL. Utilizing the Eµ-TCL1 adoptive transfer murine model, similar methods were adopted to profile the gut microbiome over the course of 7 weeks. Lastly, to evaluate the contribution of the gut microbiota to CLL development, we employed an antibiotic-mediated gut microflora ablation to the adoptive transfer Eµ-TCL1 model, with leukemia expansion monitored post-engraftment on a weekly basis. Results: A unique microbiome signature was identified in both the indolent and aggressive model of CLL. Evaluation of beta diversity, using Bray-Curtis distance metrics, confirmed distinct differences in the gut microbial communities between Eµ-TCL1 and WT B6 cohorts. At the phylum level, the gut microbiota of the Eµ-TCL1 and WT B6 cohorts were similarly dominated by Firmicutes and Bacteroidota. However, Proteobacteria Deferribacterota and Desulfobacterota were more abundant in the Eµ-TCL1 mice over 12 months as compared to age-matched WT B6. Abundance of Actinobacteriota increased specifically at 12 months in the Eµ-TCL1 mice. Additionally, LEfSe analysis showed enrichment of certain phyla in the Eµ-TCL1 mice at 4 months, 10 months, and 12 months. Presence of these bacteria paralleled with expansion of disease. In the aggressive model of CLL, beta diversity confirmed distinct differences in gut microbial communities as CLL disease progressed. Moreover, certain phyla were enriched in leukemic mice at 7 weeks post-engraftment including Proteobacteria and Actinobacteriota. Lastly, in the antibiotic-mediated gut flora ablation model, a delay of disease onset was reflected in mice with ablated gut microbiomes compared to mice with intact gut microbiomes, resulting in prolonged overall survival. Conclusion: We provide novel results associating the gut microbiome with the initiation and progression of CLL disease. In both the indolent and aggressive CLL disease models, we showed that there is a distinct gut microbiome as evident by beta diversity. A dysbiotic signature represented by increasing Proteobacteria abundance was similarly identified in both models. Proteobacteria are known to be evident in diseases characterized by inflammation. These findings support future studies to determine a potential causal mechanism between gut microbiota changes and CLL pathogenesis.

Schistosome Infection in the Humanized Mouse Model of Sickle Cell Disease

Introduction Sickle cell disease (SCD) is a hemoglobinopathy due to a single amino acid substitution in the β-chain of hemoglobin (Hb), in which glutamic acid is substituted by valine. The individuals carrying the substitution on both β-chains (HbSS) develop the disease, characterized by chronic hemolytic anemia, systemic inflammatory state, and development of acute painful vaso-occlusive crises. Globally distributed, the disease has its highest incidence in sub-Saharan Africa (SSA), where its superimposes with the distribution of infections by parasitic worms, including schistosomes. However, there is scarcity of the literature on the possible interactions between parasitic worm infections and SCD. Schistosomes are parasitic worms responsible for the disease named schistosomiasis which affects over 240 million people in the world, of which over 90 % are found in SSA. The worms live within the blood vessels of infected individuals where females lay eggs which are strongly immunogenic, causing a systemic type 2 inflammation. The disease is characterized by anemia and the formation of granulomas in the liver and intestines (for Schistosoma mansoni & S. japonicum), leading to hepatic fibrosis, pulmonary hypertension, and hepatosplenomegaly. The overlapping of the clinical features of schistosomiasis and SCD highlights the existence of possible interactions between them in areas where they are both present. Leveraging the humanized mouse model of SCD, the aim of this study is to demonstrate how schistosome infection could affect the pathophysiology of SCD or vice versa. Methods Twenty-five - 28 weeks old male and female Townes (HbAA, HbAS, HbSS) were infected with S. mansoni . Complete blood count was performed before and 8 weeks after infection. Liver and small intestines (ileum) were chemically digested with 4% KOH and eggs counted in the suspension under a microscope. Fecal pellets were also collected and dispersed in 2x PBS and eggs were counted in the suspension as for liver and intestines. Data were analyzed with GraphPad Prism 9.5.1 software by using paired t-test or Wilcoxon test. Genotypes were compared by one-way ANOVA or Kruskall-Wallis tests followed by two-stage linear step-up procedure of Benjamini-Krieger-Yekutieli for the control of false discovery rate. Results Compared to HbAA and HbAS, which did not differ between them, naïve HbSS mice had bigger livers and spleens. This pattern remained even after infection, with infected HbSS having bigger livers and spleens than infected HbAA and HbAS. After the infection, the spleen size increased only in HbAA and HbAS but not in HbSS while liver size increased in all 3 genotypes. Schistosome infection caused a significant increase in the numbers of neutrophils, monocytes, eosinophils, and basophils. However, lymphocytes number significantly decreased in HbSS only. Red blood cells (RBCs) number decreased in HbAA and HbAS but not in HbSS. Accordingly, the mean corpuscular volume (MCV) and the mean corpuscular hemoglobin (MCH) increased in HbAA and HbAS, but not in HbSS. The Hb rate was not affected by the infection while the hematocrit slightly decreased only in HbAS. However, while the platelets number decreased only in HbSS, the mean platelet volume (MPV) increased in all 3 genotypes. HbSS mice had fewer total S. mansoni egg number than HbAA and HbAS. This trend was corroborated by the number of eggs in intestinal tissues in which HbSS had fewer eggs than HbAA and HbAS. Although the number of eggs in the liver did not differ significantly between them, HbSS tended to have fewer liver eggs than HbAA and HbAS. All 3 mouse groups excreted similar number of eggs in the feces. Conclusions All 3 genotypes of Townes mice supported the development of S. mansoni worms as illustrated by the presence of eggs in their liver, intestines, and feces, making this model a good model for the study of parasitic worm infections in SCD. Schistosome infection has affected less the RBC components in HbSS as shown by no changes in RBC, Hb, MCV, and MCH values, and by no change in the spleen size. Further investigations are underway.

An alien parasite in a changing world - Ashworthius sidemi has lost its traditional seasonal dynamics.

A non-native nematode Ashworthius sidemi has emerged in captive fallow deer in Central and Eastern Europe over the last decade. Although this parasite has been spreading in the wild outside it's native distributional range and colonising local European host species since the middle of the last century, limited information has been published on the seasonality of A. sidemi and its susceptibility to anthelmintics. To address this knowledge gap, we conducted a study to investigate seasonal dynamics of the non-native parasite in the current Central European climate conditions. We collected freshly voided faecal pellets at four-week intervals from February 2018 to February 2020 at a fallow deer reserve with a known history of A. sidemi presence. The faecal pellets obtained were pooled after each site visit (n = 25) and coprocultured to obtain the third stage larvae of trichostrongylid nematodes at monthly intervals. Total genomic DNA was extracted from the recovered larvae. Using real-time multiplex PCR, A. sidemi DNA was detected in 17 out of 25 larval samples (68% prevalence). During the monitoring period, the annual administration of ivermectin based premix (Cermix) took place in January 2018, 2019, and 2020, and additionally a mixture of rafoxanide and mebendazole (Rafendazol) was administered once in spring 2019. The probability of parasite presence was significantly influenced by the time since the drug administration (p = 0.048) and the mean temperature at the location (p = 0.013). Larval samples negative for A. sidemi were always identified shortly after the drug administration. However, rapid pasture contamination by the parasite eggs from two to three months after Cermix administration and within one month after Rafendazol administration suggest only a short-lived efficacy of both administered drugs. The abundance of A. sidemi DNA was positively affected by mean temperature (p = 0.044) and remained relatively stable throughout the monitoring period, with the highest peak in August 2018 and 2019. Pasture contamination with A. sidemi eggs occurred almost all year round, with the exception of the beginning of 2018, 2019, and 2020. These findings indicate adaptation of a non-native parasite to the current climatic conditions of the Czech Republic resulted in negligible seasonal patterns of parasite egg shedding.

Assessing the diet and seed dispersal ability of non-native sambar deer (Rusa unicolor) in native ecosystems of south-eastern Australia.

Understanding the influence of non-native herbivores on ecosystems by means of dietary foraging and seed dispersal is important for understanding how non-native species can alter an invaded landscape, yet requires multiple methodologies. In south-eastern Australia, introduced sambar deer (Rusa unicolor) are rapidly expanding in range and placing native ecosystems at risk through browsing and as vectors for seed dispersal. We simultaneously investigated sambar deer dietary composition and seed dispersal using DNA sequencing and germination trials, from faecal pellets collected in alpine and wet forest ecosystems. This allowed us to contrast the dietary impacts of introduced sambar deer in different environments, and to explore the potential for habitat-specific variation in diet. DNA sequencing of the trnL, ITS2 and rbcL gene regions revealed a diverse plant species dietary composition comprising 1003 operational taxonomic units (OTUs). Sambar deer exhibited intermediate feeder behaviours dominated by forbs in alpine and shrubs in wet forest ecosystems. A large proportion of plant OTUs were considered likely to be native, however, the proportion of exotic species in the diet in both ecosystems was greater than would be expected based on the proportion of exotic species in each of the two landscapes. Seed germination trials indicated that sambar deer can disperse a substantial number of native and exotic species in both alpine and wet forest ecosystems. In alpine ecosystems, an individual sambar deer was estimated to disperse on average 816 (±193) seeds per day during the study period, of which 652 (±176) were exotic. Synthesis and applications. Our results suggest that native plant species comprise the majority of sambar deer diets in Australian ecosystems and that the introduced species is dispersing both native and exotic plant species via endozoochory. However, exotic species seedling germination numbers were significantly higher in alpine ecosystems, and given the large daily movements of sambar deer, represents a significant vector for the spread of exotic plant species. Management of native plant species and vegetation communities of conservation significance, or at risk to sambar deer browsing is of high priority, through either the removal of sambar deer or implementation of exclusion-based methods.

Deer dietary responses to wildfire: Optimal foraging, individual specialization, or opportunism?

Increasing impacts of wildfire on arid regions of the world fuelled by climate change highlight the need to better understand how natural communities respond to fire. We took advantage of a large (1660-km2 ) wildfire that erupted in northern California during an in-progress study of black-tailed deer (Odocoileus hemionus columbianus) to investigate deer use of and diets within burned and unburned habitats before and after the fire. We compared deer diet breadth to predictions of optimal foraging theory, the niche variation hypothesis, and opportunistic (i.e., generalist) foraging expectations under the assumption that overall availability and diversity of forage in burned areas declined immediately after the fire and increased as the plant community recovered in the next 3 years after the fire. We used faecal pellet counts to document space use and metabarcoding to study diet during pre-fire, post-fire, and recovery periods. Pellet counts supported predictions that deer increased use of unburned sites and reduced use of burn sites after the fire and began to return to burned sites in subsequent sampling years. Diet diversity did not differ significantly between control and burn sites before the fire, but was lower in burn than control sites post-fire (p < .001), when and where diet was dominated by oak (Quercus spp). In contrast, during subsequent years, diet diversity was higher (including more herbaceous plants) in burn than control sites (p < .05). In contrast to predictions of optimal foraging and niche variation hypotheses, individual deer foraged as generalists for which changes in dietary niche breadth paralleled fire-induced changes in diversity of the plant community.

Stool-softening effect and action mechanism of free anthraquinones extracted from Rheum palmatum L. on water deficit-induced constipation in rats

Ethnopharmacological relevanceIn traditional Chinese herbal medicine, rhubarb is said to remove accumulation with purgation, clearing heat, and discharging fire. Modern pharmacology has shown that rhubarb extract has a purgative effect when given to experimental animals in an appropriate dose. However, the active components and their mechanism of action are still not clearly defined. Aim of the studyThe current research aimed to evaluate the synergistic stool-softening effects and explore the action mechanism of rhubarb free anthraquinones (RhA) and their monomers on constipation in rats. Materials and methodsA rat model of water deficit-induced constipation was established to induce constipation, and these rats were treated with RhA and its monomers. ELISA, histopathology, immunohistochemistry, qPCR and Western blotting based on network pharmacology and molecular docking were conducted to explore the possible mechanism of action of RhA and its monomers. ResultsRhA, aloe-emodin, rhein, and chrysophanol showed stool-softening activity, and the combination of aloe-emodin and rhein had the strongest softening effect on faecal pellets. Aloe-emodin, rhein, and chrysophanol significantly increased the serum levels of vasoactive intestinal peptide (VIP), motilin (MTL), and substance P (SP), upregulated the expression of VIP, cyclase-associated protein 1 (CAP1), protein kinase A (PKA), cystic fibrosis transmembrane conductance regulator (CFTR), aquaporin 3 (AQP3), aquaporin 4 (AQP4), and aquaporin 8 (AQP8), decreased the expression of epithelial sodium channel (ENaC) and Na+/H+ exchanger 3 (NHE3), and reduced the colonic tissue concentration of Na+-K+-ATPase in the constipated rats. Osmolality of colonic fluid in model rats treated by RhA, aloe-emodin, rhein, and chrysophanol was increased. ConclusionAloe-emodin, rhein, and chrysophanol were the stool-softening components of the RhA extract, and there were certain drug-interactions between the components. RhA upregulated VIP expression, activated the cyclic adenosine monophosphate protein kinase A (cAMP/PKA) pathway, and further stimulated CFTR expression while inhibiting NHE3 and ENaC expression, resulting in a hypertonic state in the colonic lumen. Water transport could then be driven by an osmotic gradient, which in turn led to the upregulation of AQP3, AQP4, and AQP8 expression. In addition, RhA likely improved gastrointestinal motility by increasing serum VIP, SP, and MTL concentrations, thus promoting faecal excretion.

Fenchone Ameliorates Constipation-Predominant Irritable Bowel Syndrome via Modulation of SCF/c-Kit Pathway and Gut Microbiota.

In this study we sought to elucidate the therapeutic effects of fenchone on constipation-predominant irritable bowel syndrome (IBS-C) and the underlying mechanisms. An IBS-C model was established in rats by administration of ice water by gavage for 14 days. Fenchone increased the reduced body weight, number of fecal pellets, fecal moisture, and intestinal transit rate, and decreased the enhanced visceral hypersensitivity in the rat model of IBS-C. In addition, fenchone increased the serum content of excitatory neurotransmitters and decreased the serum content of inhibitory neurotransmitters in the IBS-C rat model. Meanwhile, western blot and immunofluorescence experiments indicated that fenchone increased the expressions of SCF and c-Kit. Furthermore, compared with the IBS-C model group, fenchone increased the relative abundance of Lactobacillus, Blautia, Allobaculum, Subdoligranulum, and Ruminococcaceae_UCG-008, and reduced the relative abundance of Bacteroides, Enterococcus, Alistipes, and Escherichia-Shigella on the genus level. Overall, fenchone ameliorates IBS-C via modulation of the SCF/c-Kit pathway and gut microbiota, and could therefore serve as a novel drug candidate against IBS-C.

Wild Avian Gut Microbiome at a Small Spatial Scale: A Study from a Mediterranean Island Population of Alectoris rufa.

This research is one of the few comparative descriptions at an intraspecific level of wild non-passerine microbiomes. We investigated for the first time the gut microbiome of red-legged partridges (Alectoris rufa) using fecal pellets in order to provide a more informed management. We focused on a small Italian population consisting of two demes (WEST, EAST) separated by about 20 km on the opposite sides of Elba Island. Given the small spatial scale, we set up a sampling protocol to minimize contamination from environmental bacteria, as well as differences due to variations in-among others-habitat, season, and age of feces, that could possibly affect the investigation of the three Elban sites. We found a significant divergence between the WEST and EAST Elban subpopulations in terms of microbial composition and alpha diversity. Although most represented bacterial phyla were the same in all the sites (Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes), microbiomes displayed a much higher diversity in western than in eastern partridges. This result might be related to locally diverging individual physiological needs and/or to different intensities in past releases of captive-bred birds between the two sides of Elba. We suggest that the two subpopulations should be treated as distinct management units.

Microplastics Residence Time in Marine Copepods: An Experimental Study

Microplastics are ubiquitous in aquatic environments, and in most marine environments, copepods are the main metazoans. The ingestion of microplastics by zooplankton is linked to various stresses, including oxidative stress, reduced reproductive capacities, and even mortality in nauplii. Microplastics are also reported to serve as vectors for hydrophobic contaminants. Our experimental results highlight that the retention and contact time of microplastics in copepods is quite short. The experimental results show that Parvocalanus crassirostis and Acartia pacifica defecated 75–84% and 61–71% of ingested microplastics within 60 min of ingestion. The observation raises several questions on the hypothesis of microplastic toxicity and ecological stresses: would a 180-minute contact time result in acute toxicity reported by various workers? An interesting observation was that these two copepod species did not consume microplastics larger than 50 µm in size. Considering this fact, inventories of smaller microplastics might be more important for assessing the ecological effects of MP ingestion among primary consumers in the marine food chain. Another important aspect that this study highlights is the likely change in faecal pellet sinking velocities due to the incorporation of MPs, and faecal pellets are probably efficient vectors for MP transport in the aquatic environment.

Female pond bats hunt in other areas than males and consume lighter prey when pregnant.

Animals with large energy requirements are forced to optimize their hunting strategy, which may result in differentiation of the diet between sexes and across seasons. Here, we examined spatiotemporal variation in the diet of both sexes of the Pond Bat Myotis dasycneme, a species known to have spatial segregation of sexes when the young are born and lactating. Fecal pellets were collected from live animals for a period of 15 years at various locations in the Netherlands. A total of 535 pellets were successfully analyzed by microscopy and an additional 160 pellets by DNA metabarcoding. Morphological and molecular analyses showed that the diet of pregnant and lactating pond bats differed significantly from the diet of females with no reproductive investment. Further analyses of the data showed that pregnant female pond bats are highly dependent on small prey and pupae, mainly nonbiting midges and mosquitoes (Diptera: Chironomidae and Culicidae). These insects can be found in large quantities in peatlands intersected with shallow waterways, the habitat type in which female pond bats were observed more often than males. Our results suggest that during pregnancy the spatial segregation of sexes coincides with sex-specific diets, which might reflect habitat selection based on energy requirements, in addition to lowered intraspecific competition.

Green matters: Dietary assessment of a reptile community using DNA metabarcoding

DNA metabarcoding is widely used for diet characterization and is becoming increasingly important for biodiversity conservation, allowing the understanding of trophic networks and community assemblies. However, to our knowledge, few studies have used this approach to investigate trophic interactions for whole communities and none for reptiles. In particular, few studies have examined the diet composition of Saudi Arabian reptiles, and all have used classical methods only. Therefore, in this work, a non-invasive approach using DNA metabarcoding of faecal pellets was implemented to investigate the diet composition of the reptile community of Wadi Ashar, in AlUla County, north-western Saudi Arabia Kingdom. In the overall diet composition of the community, arthropods were present in 90% of the samples, and plants were present in 63%, revealing the unforeseen importance of plants to this community as a secondary, but also a primary dietary item. For some species, this is the first time that plants have been reported in their diet. A significant effect of reptile body size on diet composition was also demonstrated, indicating its strong influence on prey selection and resource partitioning in the community. This study highlights the importance of community assessments and the power of combining these with non-invasive DNA metabarcoding to accurately assess biodiversity and feeding habits, revealing unknown ecological interactions of often neglected groups. This revolutionary tool for conservation and management provided rapid and holistic information at relatively low costs, allowing to inform local authorities about which elements are central to the sustainable management of the Wadi Ashar community.

The impact of salps (Salpa thompsoni) on the Antarctic krill population (Euphausia superba): an individual-based modelling study

BackgroundKrill (Euphausia superba) and salps (Salpa thompsoni) are key macrozooplankton grazers in the Southern Ocean ecosystem. However, due to differing habitat requirements, both species previously exhibited little spatial overlap. With ongoing climate change-induced seawater temperature increase and regional sea ice loss, salps can now extend their spatial distribution into historically krill-dominated areas and increase rapidly due to asexual reproduction when environmental conditions are favorable. Understanding the potential effects on krill is crucial, since krill is a species of exceptional trophic significance in the Southern Ocean food web. Negative impacts on krill could trigger cascading effects on its predators and prey. To address this question, we combined two individual-based models on salps and krill, which describe the whole life cycle of salp individuals and the dynamic energy budget of individual krill. The resulting new model PEKRIS (PErformance of KRIll vs. Salps) simulates a krill population for 100 years under varying chlorophyll-a concentrations in the presence or absence of salps.ResultsAll of the investigated krill population properties (abundance, mean length, and yearly egg production) were significantly impacted by the presence of salps. On the other hand, salp density was not impacted if krill were present. The medians of krill population properties deviated during variable maximum chlorophyll-a density per year when salps were introduced by − 99.9% (− 234 individuals per 1000 m3) for krill density, − 100% (− 22,062 eggs per 1000 m3) for krill eggs and − 0.9% (− 0.3 mm) for mean length of krill.ConclusionsIf both species compete for the same food resource in a closed space, salps seem to inhibit krill populations. Further simulation studies should investigate whether this effect prevails if different phytoplankton sizes and consumption preferences of krill are implemented. Furthermore, direct predation of the two species or consumption of krill fecal pellets by salps could change the impact size of the food competition.

Optical microscopic study on a novel morphological classification method of multiple diagnostic features of Sarcoptes scabiei var. hominis.

Optical microscopy is the gold standard technique used to confirm the diagnosis of scabies. Multiple diagnostic features of the pathogen Sarcoptes scabiei var. hominis (S. scabiei) can be identified under a microscope and classified into 3 categories: mites, eggs and fecal pellets. However, mite and eggshell fragments can also be observed, which have been ignored in the 2020 International Alliance for the Control of Scabies (IACS) Criteria and by most researchers. In this study, we propose a novel morphological classification method that classifies multiple diagnostic features into 5 categories and 7 subcategories. Our results revealed that 65.2% (1893 of 2896) of the positive cases were confirmed through the identification of mites, eggs or fecal pellets, whereas up to 34.6% (1003 of 2896) of the positive cases were confirmed through the identification of mite or eggshell fragments. Therefore, the important diagnostic values of mite and eggshell fragments should be emphasized. Importantly, for the first time, mite and eggshell fragments were classified into 7 subcategories, some of which are easily ignored or confused with contaminating artefacts. We believe that this novel morphological classification method will be beneficial for operator training in interpreting slides and in improving the 2020 IACS Criteria.

Homeostatic Balance of Gut Microbiota in Head and Neck Squamous Cell Carcinoma Patients during Radiotherapy.

Radiotherapy is the major treatment for head and neck squamous cell carcinoma (HNSCC). Oral microbiota changes have been described before. However, gut microbiota changes in HNSCC patients who received local radiotherapy remain unclear. We aim to investigate the dynamic change of gut microbiota composition in HNSCC patients undergoing radiotherapy and to construct the radiotherapy related gut microbiota database in HNSCC patients. We enrolled 47 HNSCC patients who scheduled with radiotherapy solely. Intensity-modulated radiotherapy (IMRT) was the standard radiotherapy technique for all the enrolled patients. The field was irradiated with a total dose of 60-66Gy in 30-33 fractions. Fecal pellets were collected at three time points. Bacterial genomic DNA was isolated using magnetic beads and then analyzed by the Illumina MiSeq Sequencing System based on the V3-V4 hypervariable regions of the 16S rRNA gene. A total of 194 genera which belonged to 27 phyla were found in 141 samples. Increased abundance of microbiota in diversity and richness was observed in mid-radiotherapy group. Moreover, Bacteroides, Blautia, and Phascolarctobacterium were three main genera in all three groups and the mid-radiotherapy group had the highest relative abundance of Phascolarctobacterium. What's more, most significantly altered bacteria shared the same variation pattern which was increased in mid-radiotherapy while decreased to the almost same level of as pre-radiotherapy in post-radiotherapy group. Local radiotherapy can affect the composition of the gut microbiota in HNSCC patients during the mid-term of radiotherapy. However, self-stabilized ability maintained the gut microbiota homeostasis in the end.

Comparative study of purgative pharmacological effects and mechanisms of Moringa oleifera leaves and Rhei Radix et Rhizoma

Moringa oleifera leaves are known for their &quot;Virechana&quot;(purgative) effect in Ayurvedic medicine in India. This study compared the purgative effects and mechanisms of M. oleifera leaves with the reference Rhei Radix et Rhizoma to establish a foundation for the further application of M. oleifera leaves in traditional Chinese medicine(TCM). Using network pharmacology and molecular docking methods, this study identified the material basis, common targets, and signaling pathways through which Rhei Radix et Rhizoma and M. oleifera leaves exerted their purgative pharmacological effects. A low-fiber diet-induced constipation mouse model was established to measure fecal parameters and small intestinal propulsion rate, and histological changes in the colon were observed using HE staining. Relative expression levels of relevant genes and target proteins were assessed using RT-qPCR and immunohistochemistry, respectively. The results showed that mapping the targets of Rhei Radix et Rhizoma and M. oleifera leaves onto the biological process network of constipation revealed close proximity, indicating that they may exert their therapeutic effects on constipation through similar biological processes. Molecular docking results indicated that compounds such as sennoside C and isoquercitrin could target serine/threonine protein kinases(AKT1) and mitogen-activated protein kinase 3(MAPK3), thereby affecting MAPK and calcium signaling pathways to promote defecation. Animal experiments demonstrated that both M. oleifera leaves and Rhei Radix et Rhizoma increased the number of fecal pellets and water content in constipated mice, improved small intestine motility, colon mucosal thickness, and muscle layer thickness, upregulated the gene expression levels of AKT1 and MAPK3 in the colon, and downregulated the expression of AQP3 protein. These findings suggest that M. oleifera leaves and Rhei Radix et Rhizoma share similarities in their therapeutic efficacy and mechanisms for treating constipation. Using Rhei Radix et Rhizoma as a reference can provide a better understanding of the characteristics of the &quot;Virechana&quot;(purgative) effect of M. oleifera leaves in TCM.

The Protective Effect of Roseburia faecis Against Repeated Water Avoidance Stress-induced Irritable Bowel Syndrome in a Wister Rat Model.

Roseburia faecis, a butyrate-producing, gram-positive anaerobic bacterium, was evaluated for its usefulness against repeated water avoidance stress (WAS)-induced irritable bowel syndrome (IBS) in a rat model, and the underlying mechanism was explored. We divided the subjects into three groups: one without stress exposure, another subjected to daily 1-hour WAS for 10 days, and a third exposed to the same WAS regimen while also receiving two different R. faecis strains (BBH024 or R22-12-24) via oral gavage for the same 10-day duration. Fecal pellet output (FPO), a toluidine blue assay for mast cell infiltration, and fecal microbiota analyses were conducted using 16S rRNA metagenomic sequencing. Predictive functional profiling of microbial communities in metabolism was also conducted. FPO and colonic mucosal mast cell counts were significantly higher in the WAS group than in the control group (male, P = 0.004; female, P = 0.027). The administration of both BBH024 (male, P = 0.015; female, P = 0.022) and R22-12-24 (male, P = 0.003; female, P = 0.040) significantly reduced FPO. Submucosal mast cell infiltration in the colon showed a similar pattern in males. In case of fecal microbiota, the WAS with R. faecis group showed increased abundance of the Roseburia genus compared to WAS alone. Moreover, the expression of a gene encoding a D-methionine transport system substrate-binding protein was significantly elevated in the WAS with R. faecis group compared to that in the WAS (male, P = 0.028; female, P = 0.025) group. These results indicate that R. faecis is a useful probiotic for treating IBS and colonic microinflammation.

Functional metagenomic and metabolomics analysis of gut dysbiosis induced by hyperoxia.

Inhaled oxygen is the first-line therapeutic approach for maintaining tissue oxygenation in critically ill patients, but usually exposes patients to damaging hyperoxia. Hyperoxia adversely increases the oxygen tension in the gut lumen which harbors the trillions of microorganisms playing an important role in host metabolism and immunity. Nevertheless, the effects of hyperoxia on gut microbiome and metabolome remain unclear, and metagenomic and metabolomics analysis were performed in this mouse study. C57BL/6 mice were randomly divided into a control (CON) group exposed to room air with fractional inspired oxygen (FiO2) of 21% and a hyperoxia (OXY) group exposed to FiO2 of 80% for 7 days, respectively. Fecal pellets were collected on day 7 and subjected to metagenomic sequencing. Another experiment with the same design was performed to explore the impact of hyperoxia on gut and serum metabolome. Fecal pellets and blood were collected and high-performance liquid chromatography with mass spectrometric analysis was carried out. At the phylum level, hyperoxia increased the ratio of Firmicutes/Bacteroidetes (p = 0.049). At the species level, hyperoxia reduced the abundance of Muribaculaceae bacterium Isolate-037 (p = 0.007), Isolate-114 (p = 0.010), and Isolate-043 (p = 0.011) etc. Linear discriminant analysis effect size (LEfSe) revealed that Muribaculaceae and Muribaculaceae bacterium Isolate-037, both belonging to Bacteroidetes, were the marker microbes of the CON group, while Firmicutes was the marker microbes of the OXY group. Metagenomic analysis using Kyoto Encyclopedia of Genes and Genomes (KEGG) and Carbohydrate-Active enZYmes (CAZy) revealed that hyperoxia provoked disturbances in carbohydrate and lipid metabolism. Fecal metabolomics analysis showed hyperoxia reduced 11-dehydro Thromboxane B2-d4 biosynthesis (p = 1.10 × 10-11). Hyperoxia blunted fecal linoleic acid metabolism (p = 0.008) and alpha-linolenic acid metabolism (p = 0.014). We showed that 1-docosanoyl-glycer-3-phosphate (p = 1.58 × 10-10) was the most significant differential serum metabolite inhibited by hyperoxia. In addition, hyperoxia suppressed serum hypoxia-inducible factor-1 (HIF-1, p = 0.007) and glucagon signaling pathways (p = 0.007). Hyperoxia leads to gut dysbiosis by eliminating beneficial and oxygen strictly intolerant Muribaculaceae with genomic dysfunction of carbohydrate and lipid metabolism. In addition, hyperoxia suppresses unsaturated fatty acid metabolism in the gut and inhibits the HIF-1 and glucagon signaling pathways in the serum.

Total Mass Flux in the Northern Humboldt Current System: Rates and Contribution Sources from Central Peru (12° S)

The total mass flux (TMF) of particulate organic matter (POM) is key for understanding the energetic transfer within the “biological pump” (i.e., involving the carbon cycle), reflecting a critical connection between the surface and the bottom. A fixed multi-sediment trap was installed at 30 m depth in Callao Bay, central Peru from March to December 2020. After recovery, samples were dried and weighed to calculate the TMF and pellet flux. The average TMF was 601.9 mg·m−2·day−1, with 70.2 and 860 mg·m−2·day−1 as the lowest and highest values during “normal conditions”. Zooplankton fecal pellets (ZFP) were found in ovoid (e.g., larvae) and cylindrical (e.g., adult copepods) shapes and their flux contribution to TMF was low, ranging from 0.17 to 85.59 mg·m−2·day−1. In contrast with ZFP, fish fecal pellets (FFP) were found in fragments with a cylindrical shape, and their contribution to the TMF was higher than ZFP, ranging from 1 to 92.56 mg·m−2·day−1. Mean sinking velocities were 4.63 ± 3.47 m·day−1 (ZFP) and 432.27 ± 294.26 m·day−1 (FFP). There is a considerable difference between the ZFP and FFP contributions to TMFs. We discuss the implications of these results regarding a still poorly understood process controlling the POM flux off the Peruvian coast.

Seasonal patterns of vertical flux in the northwestern Barents Sea under Atlantic Water influence and sea-ice decline

The northern Barents Sea is a productive Arctic inflow shelf with a seasonal ice cover and as such, a location with an efficient downward export of particulate organic matter through the biological carbon pump. The region is under strong influence of Atlantification and sea-ice decline, resulting in a longer open water and summer period. In order to understand how these processes influence the biological carbon pump, it is important to identify the seasonal and spatial dynamics of downward vertical flux of particulate organic matter. In 2019 and 2021, short-term sediment traps were deployed between 30 and 200 m depth along a latitudinal transect in the northwestern Barents Sea during March, May, August and December. Vertical flux of particulate organic carbon, δ13C and δ15N values, Chl-a, protists and fecal pellets were assessed. We identified a clear seasonal pattern, with highest vertical flux in May and August (178 ± 202 and 159 ± 79 mg C m−2 d−1, respectively). Fluxes in December and March were < 45 mg C m−2 d−1. May was characterized by diatom- and Chl a-rich fluxes and high spatial variability, while fluxes in August had a higher contribution of fecal pellets and small flagellates, and were spatially more homogenous. Standing stocks of suspended particulate organic matter were highest in August, suggesting a more efficient retention system in late summer. The strong latitudinal sea-ice gradient and the influence of Atlantic Water probably led to the high spatial variability of vertical flux in spring, due to their influence on primary productivity. We conclude that the efficiency of the biological carbon pump in a prolonged open-water period depends on the reworking of small, slow sinking material into efficiently sinking fecal pellets or aggregates, and the occurrence of mixing.

Microcosm study of the effects of polyester microfibers on the indigenous marine amphipod (Cyphocaris challengeri) in the Strait of Georgia (BC, Canada)

Microplastics (MP) remain contaminants of great concern in the ocean because of their abundance, prevalence, and threat to marine organisms. Still, there is a great need for studies on the impact of MP on marine zooplankton. Here, we investigated the effects of polyethylene terephthalate (PET) microfibers (Mf) on the survival, Mf ingestion and retention, predation, and fecal pellets (FP) of the marine amphipod (Cyphocaris challengeri) at environmentally relevant concentrations (0, 10, 100, 1000, 10,000 and 50,000 Mf·L−1) and varied exposure time (24, 48 and 72 h). Our study demonstrated that exposure of C. challengeri to PET Mf did not affect their survival. The average number of ingested Mf and the Mf ingestion rate increased significantly with Mf concentrations. Nonetheless, the Mf ingestion rates by C. challengeri decreased significantly between 24 and 72 h in the two highest Mf treatments (10,000 and 50,000 Mf·L−1), suggesting careful rejection of the Mf or reduced feeding activity. Indeed, PET Mf significantly reduced the copepod feeding rate of the amphipods at Mf concentrations ≥1000 Mf·L−1 after 24 and 48 h of exposure duration. Over time, prey intake reduction in amphipods due to Mf ingestion could affect their reproductive outcome, growth, development, and cellular and ecosystem function. The encapsulation of PET Mf into the FP of C. challengeri significantly increased the FP density and sinking velocities, ultimately doubling the transfer rate of the FP from the surface waters to the sediments in SoG. Conversely, ingesting PET microfibers and their incorporation in FP will potentially enhance the role of C. challengeri in the biological C pump and sequestration in SoG. Our study showed that changes in Mf concentration had a more significant effect on C. challengeri Mf ingestion and ingestion rate, prey consumption, FP density and sinking velocity than the exposure time.