Gut Contents Research Articles

Myricetin alleviates diabetic cardiomyopathy by regulating gut microbiota and their metabolites

BackgroundThe gut microbiota is involved in the pathogenesis of diabetic cardiomyopathy (DCM). Myricetin protects cardiac function in DCM. However, the low bioavailability of myricetin fails to explain its pharmacological mechanisms thoroughly. Research has shown that myricetin has a positive effect on the gut microbiota. We hypothesize that myricetin improves the development of DCM via regulating gut microbiota.MethodsDCM mice were induced with streptozotocin and fed a high-fat diet, and then treated with myricetin by gavage and high-fat diet for 16 weeks. Indexes related to gut microbiota composition, cardiac structure, cardiac function, intestinal barrier function, and inflammation were detected. Moreover, the gut contents were transplanted to DCM mice, and the effect of fecal microbiota transplantation (FMT) on DCM mice was assessed.ResultsMyricetin could improve cardiac function in DCM mice by decreasing cardiomyocyte hypertrophy and interstitial fibrosis. The composition of gut microbiota, especially for short-chain fatty acid-producing bacteria involving Roseburia, Faecalibaculum, and Bifidobacterium, was more abundant by myricetin treatment in DCM mice. Myricetin increased occludin expression and the number of goblet cells in DCM mice. Compared with DCM mice unfed with gut content, the cardiac function, number of goblet cells, and expression of occludin in DCM mice fed by gut contents were elevated, while cardiomyocyte hypertrophy and TLR4/MyD88 pathway-related proteins were decreased.ConclusionsMyricetin can prevent DCM development by increasing the abundance of beneficial gut microbiota and restoring the gut barrier function.

Polystyrene degradation by bacteria isolated from the larvae of <i>Rhynchophorusphoenicis</i>

The larvae of insects of the order Coleoptera have been reported to biodegrade plastics aided by their chewing mouthparts and the activities of their gut biota. However, there is no report of this ability by the African palm weevil (Rhynchophorus phoenicis). This study aims to the ability of R. phoenicis larvae to biodegrade polystyrene (PS). A total of 100 R. phoenicis larvae were fed for 21 days with PS foam, and afterwards, the gut contents of survivors were investigated for possible PS-degrading bacteria. Bacterial isolates were screened for PS biodegradation in an Erlenmeyer flask with PS film as the sole carbon source, in a mineral salt medium (MSM) at a temperature of 30oC and a pH of 7, for a period of 28 days. The isolates were used for biodegradation assay under the same conditions, for 60 days. The weight of PS films was determined before and after the biodegradation assay. Chemical changes in the films were confirmed by Fourier Transform Infrared (FTIR) spectroscopy. Two bacterial isolates were recovered from the gut of the only surviving R. phoenicis larvae fed with 100% PS. The isolates were identified based on their 16S rRNA sequences as Lysinibacillus macriodes and Pantoea dispersa with accession numbers OQ652017 and OQ652023 respectively. The isolates caused an 8.8% reduction in the weight of PS film and FTIR spectroscopy results confirmed the formation of groups suggestive of degradation products with the carbonyl group showing up as absorption peaks in the range of 1640-1760 cm-1 and the hydroxylic group at 3000-3700 cm-1 . The isolates were able to produce polyhydroxyalkanoate (PHA) equivalent to 1.4g/L, under PS degradation conditions. Therefore, coupling the biodegradation of PS with PHAproduction could be useful for the valorization of PS waste.

Gut metabolic changes during pregnancy reveal the importance of gastrointestinal region in sample collection.

Studies of gastrointestinal physiology and the gut microbiome often consider the influence of intestinal region on experimental endpoints. However, this same consideration is not often applied to the gut metabolome. Understanding the contribution of gut regionality may be critically important to the rapidly changing metabolic environments, such as during pregnancy. We sought to characterize the difference in the gut metabolome in pregnant mice stratified by region-comparing the small intestine, cecum, and feces. Pre-pregnancy feces were collected to understand the influence of pregnancy on the fecal metabolome. Feces were collected from CD-1 female mice before breeding. On gestation day (GD) 18, gut contents were collected from the small intestine, cecum, and descending colon. Metabolites were analyzed with LC-MS/MS using the Biocrates MetaboINDICATOR™ MxP® Quant 500 kit. Of the 104 small molecule metabolites meeting analysis criteria, we found that 84 (81%) were differentially abundant based on gut region. The most significant regional comparison observed was between the cecum and small intestines, with 52 (50%) differentially abundant metabolites. Pregnancy itself altered 41 (39.4%) fecal small molecule metabolites. The regional variation observed in the gut metabolome are likely due to the microbial and physiological differences between the different parts of the intestines. Additionally, pregnancy impacts the fecal metabolome, which may be due to evolving needs of both the dam and fetus.

Detailed analysis of prey taxonomic composition indicates feeding habitat partitioning amongst co-occurring invasive gobies and native European perch

One of the negative impacts of non-native invasive species on trophic interactions in an invaded ecosystem occurs via increased interspecific competition for food resources between the invader and local species of the same food niche. In freshwaters, there are usually several fish species that feed on similar food resources. Ponto-Caspian gobies are amongst the most successful and widespread invaders colonising European waterways. They have a wide food niche and an opportunistic feeding strategy, with a focus on benthic invertebrates and piscivory occurring occasionally mainly in the case of large individuals. Competition with native percids for food resources is predicted on the basis of high dietary overlap. However, studies published so far provide no unequivocal answer. In order to resolve this question, we conducted a comparative taxonomic analysis of gut content, with an emphasis on chironomids and amphipods, of the invasive monkey goby (Neogobius fluviatilis), racer goby (Babka gymnotrachelus) and the native Eurasian perch (Perca fluviatilis) occurring sympatrically in a large lowland European river, the Bug River in Poland. We found that each species forages in slightly different habitats, as indicated by the different composition of prey species in the gut content. This suggests feeding niche partitioning between the studied species facilitating their co-existence and reduction or avoidance of competition for food resources. Resource partitioning regarding prey types and foraging habitats is a mechanism for permitting the co-existence of closely-related alien gobies with similar food preferences in the invaded waters and co-occurrence with local species. This mechanism can contribute to their invasion success, as observed in European waters during the recent decades. We also demonstrate that precise prey identification to the lowest possible taxon is crucial to reveal the dietary overlap between co-occurring fish species and to predict the impact of alien invaders on native species through interspecific competition, as well as to recommend such an approach in studies upon fish foraging strategies.

An engineered bacterial symbiont allows noninvasive biosensing of the honey bee gut environment.

The honey bee is a powerful model system to probe host-gut microbiota interactions, and an important pollinator species for natural ecosystems and for agriculture. While bacterial biosensors can provide critical insight into the complex interplay occurring between a host and its associated microbiota, the lack of methods to noninvasively sample the gut content, and the limited genetic tools to engineer symbionts, have so far hindered their development in honey bees. Here, we built a versatile molecular tool kit to genetically modify symbionts and reported for the first time in the honey bee a technique to sample their feces. We reprogrammed the native bee gut bacterium Snodgrassella alvi as a biosensor for IPTG, with engineered cells that stably colonize the gut of honey bees and report exposure to the molecules in a dose-dependent manner through the expression of a fluorescent protein. We showed that fluorescence readout can be measured in the gut tissues or noninvasively in the feces. These tools and techniques will enable rapid building of engineered bacteria to answer fundamental questions in host-gut microbiota research.

Dietary tendencies of the Early Jurassic pterosaurs Campylognathoides Strand, 1928, and Dorygnathus Wagner, 1860, with additional evidence for teuthophagy in Pterosauria

ABSTRACT The diets and feeding strategies of pterosaurs remain a poorly known although speculatively debated topic in vertebrate paleontology. Fossilized gut contents, which offer a crucial direct line of evidence to help decipher these elusive questions, are only known from a handful of pterosaur specimens in a few notable fossil Lagerstätten, such as the Solnhofen Limestone of Bavaria. Although extremely rare, pterosaurs can be exceptionally well preserved in the Lower Jurassic (Toarcian) Posidonia shale of Baden–Württemberg but, until now, none have been reported with identifiable gut contents. Here, we describe fossilized gut contents in two Posidonia Shale pterosaurs: Dorygnathus banthensis (Rhamphorhynchidae) and Campylognathoides zitteli (Campylognathoididae). Dorygnathus is shown to be piscivorous as indicated by the inclusion of the small teleost Leptolepis sp. preserved inside of the abdominal cavity. The gastrointestinal tract of Campylognathoides preserves associated accumulations of belemnoid hooklets referrable to Clarkeiteuthis conocauda and thereby demonstrating a teuthophagous diet. These findings represent the first convincing evidence for belemnoids contributing to the diet of a pterosaur and hint at a possible nocturnal hunting behavior for Campylognathoides. Previous hypotheses regarding dietary trophic partitioning based on differentiating skull anatomy in Posidonia Shale pterosaurs are supported.

Dietary partitioning among three cryptobenthic reef fish mesopredators revealed by visual analysis, metabarcoding of gut content, and stable isotope analysis

AbstractUnderstanding how mesopredators partition their diet and the identity of consumed prey can assist in understanding the ecological role predators and prey play in ecosystem trophodynamics. Here, we assessed the diet of three common coral reef mesopredators; Pseudochromis flavivertex, Pseudochromis fridmani, and Pseudochromis olivaceus from the family Pseudochromidae, commonly known as dottybacks, using a combination of (i) visual stomach content analysis, (ii) stomach content DNA metabarcoding (18S, COI), and (iii) stable isotope analysis (δ15N, δ13C). In addition, P. flavivertex is found in two distinct color morphs in the Red Sea, providing an opportunity to analyze intra‐morph differences. These techniques revealed partitioning in the dietary composition and resource use among species. Arthropods comprised the main dietary component of P. flavivertex (18S > 60%; COI > 10%) and P. olivaceus (18S = 57.2%), while P. fridmani ingested predominantly mollusks (18S = 51.3%, COI = 24.6%). Despite being small predators, microplastics were found in the gut content of some of these fishes. Stable isotope analysis showed differences in species' isotopic niche breadth and trophic position. Pseudochromis olivaceus presented the largest isotopic niche (SEAC = 1.61‰2), while P. fridmani showed the smallest isotopic niche (SEAC = 0.45‰2) among species. Although the two techniques used for stomach content analysis did not show differences in the diet within color morphs of P. flavivertex, they differed in the isotopic niche and resource use. Despite our limited sampling, our findings provide evidence of species‐specific differences in the trophic ecology of dottybacks and demonstrate their important role as predators of cryptic invertebrates and small fishes. This study highlights the importance of combining several approaches (short‐term: visual analysis and DNA metabarcoding; and long‐term: isotope analysis) when assessing the feeding habits of coral reef fish, as they provide complementary information necessary to delimit their niches and understand the role that small mesopredators play in coral reef ecosystems.

Effects of mining activities on fish communities and food web dynamics in a lowland river.

Fish communities of streams and rivers might be substantially subsidized by terrestrial insects that fall into the water. Although such animal-mediated fluxes are increasingly recognized, little is known about how anthropogenic perturbations may influence the strength of such exchanges. Intense land use, such as lignite mining, may impact a river ecosystem due to the flocculation of iron (III) oxides, thus altering food web dynamics. We compared sections of the Spree River in North-East Germany that were greatly influenced by iron oxides with sections located downstream of a dam where passive remediation technologies are applied. Compared to locations downstream of the dam, the abundance of benthic macroinvertebrates at locations of high iron concentrations upstream of the dam was significantly reduced. Similarly, catch per unit effort of all fish was significantly higher in locations downstream of the dam compared to locations upstream of the dam, and the condition of juvenile and adult piscivorous pike Esox lucius was significantly lower in sections of high iron concentrations. Using an estimate of short-term (i.e., metabarcoding of the gut content) as well as longer-term (i.e., hydrogen stable isotopes) resource use, we could demonstrate that the three most abundant fish species, perch Perca fluviatilis, roach Rutilus rutilus, and bleak Alburnus alburnus, received higher contributions of terrestrial insects to their diet at locations of high iron concentration. In summary, lotic food webs upstream and downstream of the dam greatly differed in the overall structure with respect to the energy available for the highest tropic levels and the contribution of terrestrial insects to the diet of omnivorous fish. Therefore, human-induced environmental perturbations, such as river damming and mining activities, represent strong pressures that can alter the flow of energy between aquatic and terrestrial systems, indicating a broad impact on the landscape level.

Increased ladybird predation and metabolism do not counterbalance increased field aphid population growth under experimental warming

Abstract Climate change may have diverse and complex impacts on species interactions, destabilizing food webs and ecosystem services. The effects of warming on the top‐down biological control of crop pests have been considerably less studied than bottom‐up effects through crop physiological changes. We studied the effect of a 2°C warming in the laboratory and in wheat fields on the predation and metabolism of Harmonia axyridis on wheat aphids using molecular gut content analysis. We also measured the effects of warming on the predation rate and functional response of H. axyridis on each aphid species in the laboratory, as well as on DNA degradation rate. Field densities of Sitobion avenae and Rhopalosiphum padi, the two most abundant wheat aphid species, were increased by 2 and 2.5 times, respectively, under experimental warming, but densities of H. axyridis were not. Field predation rate of H. axyridis on these two aphid was found to be about 25% lower under elevated temperature. This could have been due to faster prey digestion, since degradation of the preferred aphid species, Sitobion avenae, was 1.5 times faster under elevated temperature. However, the functional response of H. axyridis larvae on these two species was 1.5 times higher under warming over the range of prey densities tested (50–250 over 24 h). The total predation rate of H. axyridis larvae on a mixture of S. avenae, R. padi and Schizaphis graminum aphid prey was also increased by 1.4 times, but consumption of R. padi aphids was increased while that of S. graminum was decreased under warming. Overall, our results show that global warming could strongly increase pest outbreaks and destabilize biological pest control, which would likely result in accrued yield losses. Read the free Plain Language Summary for this article on the Journal blog.

Diet Composition and Feeding Habits of Fish Larvae of Five Species in the Burullus Lake, Egypt

Feeding habits of fish larvae were analysed in a comparative study of five species (Oreochromis niloticus, O. aureus, Tilapia zilli, Mugil cephalus and Liza ramada) from the Burullus Lake. We investigated the potential influence of larvae size on their feeding and looked for common patterns in larval prey preference. Gut contents of a total of 1068 larvae were examined. The feeding habits of the examined larvae shared some characteristics. As larvae of the five species grew, the preferred prey size and the number and diversity of prey in the gut increased. On the other hand, larval feeding also differed in several aspects, especially differences in the composition of preferred prey items. For Cichlidae larvae, the dominant prey was the rotifer Brachionus plicatilis followed by copepodite stages. For M. cephalus larvae, the copepods Paracalanus sp and Acartia sp were the most important diets, while for L. ramada, decapod larvae were the most important. The Mugilidae larvae consumed significantly larger prey than the cichlid larvae, which could be related to their morphology, especially the mouth size. Ivlev’s selectivity index calculated for larvae showed positive selection for particular prey. In all the species, copepods were the most selected, particularly for Mugillidae larvae, but for Cichlidae larvae, the rotifer Brachionus competed with copepods as a selected prey. This dietary study of fish larvae of these important species is essential for the development of fisheries and can be implemented in further related studies of other areas.

The Stool Microbiome in African Ruminants: A Comparative Metataxonomic Study Suggests Potential for Biogas Production

Lignocellulosic biomass is a promising substrate for anaerobic digestion (AD) in renewable energy generation but presents a significant challenge during the hydrolysis stage of conventional AD due to the recalcitrant nature of this biomass substrate. Rumen fluid is often employed as a bioaugmentation seed to enhance hydrolysis in the AD of lignocellulosic substrates due to its richness in hydrolytic bacteria. However, using rumen fluid to enhance AD processes presents substantial hurdles, including the procurement difficulties associated with rumen fluid and ethical concerns. In this study, the fecal microbiota of 10 African ruminant species from a large zoological park (Bioparc) in Valencia, Spain, were studied using 16S rRNA gene amplicon sequencing. In this study, the fecal microbiota of 10 African ruminant species from a large zoological park (Bioparc) in Valencia, Spain, were studied using 16S rRNA gene amplicon sequencing. The investigation revealed potential similarities between the fecal microbiota from the African ruminants’ and cows’ rumen fluids, as suggested by theoretical considerations. Although direct comparative analysis with cow rumen fluid was not performed in this study, the theoretical framework and existing literature hint at potential similarities. According to our results, the Impala, Blesbok, Dikdik and Bongo ruminant species stood out as having the greatest potential to be used in bioaugmentation strategies. Key genera such as Fibrobacter, Methanobrevibacter, and Methanosphaera in Impala samples suggested Impala rumen fluid’s involvement in cellulose breakdown and methane production. Blesbok and Dikdik exhibited a high abundance of Bacillus and Atopostipes, potentially contributing to lignin degradation. The richness of Prevotellaceae and Rikenellaceae in the Bongo fecal samples is probably associated with structural carbohydrate degradation. Taken together, our results shed light on the microbial ecology of the gut contents of a whole set of Bovidae ruminants and contribute to the potential application of gut microbiota in AD.

Effects of fecal microbiota transplantation on metabolic health of DBA mice.

Numerous studies have demonstrated that C57BL/6 mice exhibit superior growth rates and overall growth performance compared to DBA mice. To investigate whether this discrepancy in growth performance is linked to the composition of gut microorganisms, we conducted fecal microbiome transplantation (FMT) experiments. Specifically, we transplanted fecal fluids from adult C57BL/6 mice, high-fat C57BL/6 mice, and Wistar rats into weaned DBA mice (0.2mL/d), and subsequently analyzed their gut contents and gene expression through 16S rRNA sequencing and transcriptome sequencing. During the test period, C57BL/6 mice and Wistar rats were provided with a normal diet, and high-fat C57BL/6 mice were provided with a high-fat diet. The results of our study revealed that mice receiving FMT from all three donor groups exhibited significantly higher daily weight gain and serum triglyceride (TG) levels compared to mice of CK group. 16S rRNA sequensing unveiled substantial differences in the abundance and function of the gut microbiota between the FMT groups and the CK group. Transcriptome analysis revealed a total of 988 differential genes, consisting of 759 up-regulated genes and 187 down-regulated genes, between the three experimental groups and the CK group. Functional Gene Ontology (GO) annotation suggested that these genes were primarily linked to lipid metabolism, coagulation, and immunity. Pearson correlation analysis was performed on the differential genes and clusters, and it revealed significant correlations, mainly related to processes such as fatty acid metabolism, fat digestion and absorption, and cholesterol metabolism. In summary, FMT from dominant strains improved the growth performance of DBA mice, including body weight gain, institutional growth, and immune performance. This change may be due to the increase of probiotic content in the intestinal tract by FMT and subsequent alteration of intestinal gene expression. However, the effects of cross-species fecal transplantation on the intestinal flora and gene expression of recipient mice were not significant.

Post-ingestive stability of a mulberry Kunitz-type protease inhibitor MnKTI-1 in the digestive lumen of silkworm: dual inhibition towards α-amylase and serine protease.

Adaptation of specialist insects to their host plants and defense responses of plants to phytophagous insects have been extensively recognized while the dynamic interaction between these two events has been largely underestimated. Here, we provide evidence for characterization of an unrevealed dynamic interaction mode of digestive enzymes of specialist insect silkworm and inhibitor of its host plant mulberry tree. MnKTI-1, a mulberry Kunitz-type protease inhibitor, whose messenger RNA (mRNA) transcription and protein expression in mulberry leaf were severely triggered and up-regulated by tens of times in a matter of hours in response to silkworm, Bombyx mori, and other mulberry pest insects, suggesting a quick response and broad spectrum to insect herbivory. MnKTI-1 proteins were detected in gut content and frass of specialist B. mori, and exhibited significant post-ingestive stability. Recombinant refolded MnKTI-1 (rMnKTI-1) displayed binding affinity to digestive enzymes and a dual inhibitory activity to α-amylase BmAmy and serine protease BmSP2956 in digestive juice of silkworm. Moreover, data from in vitro assays proved that the inhibition of recombinant rMnKTI-1 to BmAmy can be reverted by pre-incubation with BmSP15920, an inactivated silkworm digestive protease that lack of complete catalytic triad. These findings demonstrate that mulberry MnKTI-1 has the potential to inhibit the digestive enzyme activities of its specialist insect herbivore silkworm, whereas this insect may employ inactivated proteases to block protease inhibitors to accomplish food digestion. The current work provides an insight to better understand the interacting mode between host plant Kunitz protease inhibitors and herbivorous insect digestive enzymes. © 2024 Society of Chemical Industry.

Towards the understanding of the uptake and depuration of microplastics in the ragworm Hediste diversicolor: Field and laboratory study

An important number of studies have evaluated the presence of microplastics, particles with a size below 5 mm, in aquatic organisms. Studies have shown that these fragments are widely present in the marine environment, but research on the estuarine ecosystem is still scarce. In this study, two different approaches were used to evaluate the presence and ingestion of plastic particles in the ragworm Hediste diversicolor: a field study for the environmental assessment and a laboratory experiment in controlled condition. For the environmental evaluation, ingestion of microplastics was evaluated in the ragworm H. diversicolor sampled from the mudflats of the Seine estuary (France) during March and June 2017 and 2018, on two locations: S1 and S2, both characterized by high anthropogenic pressures, and for S2 a more influential hydrodynamic component. Ingestion of microplastics was measured in ragworms tissues and in gut content (sediment) after depuration. The number of particles as well as their size, shape and color were reported and compared between sampling period and locations. Results showed the presence of a low number of particles in both worms and gut content. In gut content, 45.6% and 87.58% of samples from site S1 and S2 respectively contained plastic like particles. In worms, 41.7% (S1) and 75.8% (S2) of analysed samples contained plastic like items. The lowest mean number of particles was 0.21 ± 0.31 (S1 in June 2017) in worms’ tissues, but 0.80 ± 0.90 (S1 in June 2017) in the gut content and the highest was 1.47 ± 1.41 (S2 in April 2017) while the highest number was 2.55 ± 2.06 (S2 in June 2017) in worms and gut content respectively. The majority of suspected microplastics observed were fibers (66%) and fragments (27%), but films (3.7%) foam (2.1%), and granules (0.2%) were also identified. In addition, the most polymer type observed by Raman spectroscopy was polypropylene. Furthermore, a preliminary study of the ingestion and egestion of fluorescent polyethylene (PE) microbeads in the digestive tract of ragworms was conducted after exposure through water, during 1h at 1.2 × 106 MP/mL. Results showed a rapid turnover of PE microbeads throughout the digestive tract of worms especially after exposure through water. This study revealed that microplastics are ingested by the ragworm H. diversicolor but do not seem to bioaccumulate. More research is needed to measure potential chronic effects of microplastics on physiological parameters of H. diversicolor and potential trophic transfer of microplastics.

Analisis Isi Perut Ikan Apogonidae di Teluk Gilimanuk, Bali

The types of natural food consumed by fish can vary according to their species and its age level. The purpose of this study was to determine the types of organisms feed by Apogonidae fishes by observing their gut contents and to determine the type of feeding habits of these fishes. This research was conducted at two sampling sites within Gilimanuk Bay, Bali. Specimen collection was conducted in the morning (07.00 am) using a scoop net while scuba diving. We successfully collected 32 individual Apogonidae, which consist of eight species. Each sample was dissected and the contents of the stomach were removed from the esophagus to the intestine. The stomach contents were preserved using 4% formalin, and then the samples were observed under a binocular microscope with 40x magnification. The results showed that the highest composition of food species found as the main food was the Copepod of 59.86% which was fed by Sphaeramia nematoptera, Cheilodipterus artus, Fibramia thermalis, Pterapogon kaudernii, Zoramia leptacantha, Rhabdamia gracilis, and Ostorhichus hoevenii, Bacillariophyceae by 31.97% were feed by S. nematoptera, C. artus, O. hartzfeldii, F. thermalis, P. kauderni, Z. leptacantha, R. gracilis, and O. hoevenii. The other class of plankton only made up a small part of the food composition of the Apogonidae fishes, which is as much as 8.16%. Based on our results, we conclude that Apogonidae fishes in Gilimanuk Bay were plankton feeders where all the food found comes from phytoplankton and zooplankton organisms.

Gut microbiota-dependent modulation of pre-metastatic niches by Jianpi Yangzheng decoction in the prevention of lung metastasis of gastric cancer

Aim of the studyTo evaluate the in vitro and in vivo anti-metastasis efficacy of Jianpi Yangzheng (JPYZ) decoction against gastric cancer (GC) and its potential mechanisms. Materials and methodsThe distant metastasis of GC cells administered via tail vein injection was assessed using the pre-metastatic niche (PMN) model. 16S rRNA sequencing and GC–MS/MS were applied to determine the component of the gut microbiota and content of short-chain fatty acids (SCFAs) in feces of mice, respectively. The proportion of myeloid-derived suppressor cells (MDSCs) in the lung was evaluated by flow cytometry and immunofluorescence. Serum or tissue levels of inflammation factors including IL-6, IL-10 and TGF-β were determined by ELISA or Western blot respectively. ResultsInjecting GC cells into the tail vein of mice led to the development of lung metastases and also resulted in alterations in the composition of gut microbiota and the levels of SCFAs produced. Nevertheless, JPYZ treatment robustly impeded the effect of GC cells administration. Mechanically, JPYZ treatment not only prevented the alteration in gut microbiota structure, but also restored the SCFAs content induced by GC cells administration. Specifically, JPYZ treatment recovered the relative abundance of genera Moryella, Helicobacter, Lachnoclostridium, Streptococcus, Tuzzerella, GCA-900066575, uncultured_Lachnospiraceae, Rikenellaceae_RC9_gut_group and uncultured_bacterium_Muribaculaceae to near the normal control levels. In addition, JPYZ abrogated MDSCs accumulation in the lung tissue and blocked inflammation factors overproduction in the serum and lung tissues, which subsequently impede the formation of the immunosuppressive microenvironment. Correlation analysis revealed that the prevalence of Rikenellaceae in the model group exhibited a positive correlation with MDSCs proportion and inflammation factor levels. Conversely, the scarcity of Muribaculaceae in the model group showed a negative correlation with these parameters. This suggests that JPYZ might exert an influence on the gut microbiota and their metabolites, such as SCFAs, potentially regulating the formation of the PMN and consequently impacting the outcome of GC metastasis. ConclusionThese findings suggest that GC cells facilitate metastasis by altering the gut microbiota composition, affecting the production of SCFAs, and recruiting MDSCs to create a pro-inflammatory pre-metastatic niche. JPYZ decoction counteracts this process by reshaping the gut microbiota structure, enhancing SCFA production, and inhibiting the formation of the pre-metastatic microenvironment, thereby exerting an anti-metastatic effect.

Carrageenan oligosaccharide alleviates intestinal damage via gut microflora through activating IMD/relish pathway in female Drosophila melanogaster.

Recent evidence suggests the anti-inflammatory effect of carrageenan oligosaccharides (COS). The effects of COS on intestinal injury induced by 0.6% sodium dodecyl sulfate (SDS) and the molecular mechanisms involved were investigated in this study. 0.625, 1.25, and 2.5 mg/mL COS in diet had no toxic effect in flies, and they could all prolong SDS-treated female flies' survival rate. 1.25 mg/mL COS prevented the development of inflammation by improving the intestinal barrier integrity and maintaining the intestinal morphology stability, inhibited the proliferation of intestine stem cells (ISCs), and the production of lysosomes induced by SDS, accompanied by a decrease in the expression of autophagy-related genes. Moreover, COS decreased the active oxygen species (ROS) content in gut and increased the antioxidant activity in SDS-induced female flies, while COS still played a role in increasing survival rate and decreasing intestinal leakage in CncC-RNAi flies. The improvement of anti-inflammation capacity may be associated with the regulation of intestinal microflora with COS supplementation for Drosophila melanogaster. COS changed the gut microbiota composition, and COS had no effect on germ-free (GF) flies. It is highlighted that COS could not work in Relish-RNAi flies, indicating relish is required for COS to perform beneficial effects. These results provide insights into the study of gut microbiota interacting with COS to modulate intestinal inflammation in specific hosts.

Competitive interaction in headwaters: slow upstream migration leads to trophic competition between native and non-native amphipods

The spread of non-native species is one of the outcomes of global change, threatening many native communities through predation and competition. Freshwater ecosystems are particularly affected by species turnover with non-native species. One species that has been established in Central Europe for many decades – or even a few centuries – is the amphipod crustacean Gammarus roeselii. Although G. roeselii is nowadays widespread in major river systems, there have been recent reports of its spread into smaller streams that are typically inhabited by the native species Gammarus fossarum. Due to their leaf shredding ability, G. fossarum takes up a key position in headwater streams. This raises the important question, to what extent G. roeselii can equivalently take over this function. To answer this question, we collected both species from nine different sites in a mid-mountain river system (Kinzig catchment, Hesse, Germany) and investigated their functional similarity using a combination of stable isotope analysis, gut content and functional morphology. The species hardly differed in morphological characteristics, only females showed differences in some traits. Gut content analysis indicated a broad dietary overlap, while stable isotopes showed a higher trophic position of G. roeselii. The observed functional overlap could intensify interspecific competition and allow the larger and more predaceous G. roeselii to replace G. fossarum in the future as a headwater keystone species. However, the differentiation in the stable isotopes also shows that co-existence can occur by occupying different trophic niches. Moreover, the wide range of inhabited sites and exploited resources demonstrate the omnivorous lifestyle of G. roeselii, which is likely to help the species succeed in rapidly changing environments.

Food and Feeding Habits of Mystus tengara (Hamilton, 1822) of Gomati River and Rudrasagar Lake, Tripura, India

Mystus tengara is a popular food fish species due to its taste, and one of the potential ornamental fish species in ornamental trades. A total of 237 specimens of Mystus tengara [1] species were collected from Rudra Sagar Lake and Kemtali. 47 food items were observed in the gut of Mystus tengara. The present study has been performed on the food and feeding habits, Gastro Somatic Index, Relative Length of Gut, Fullness and feeding Intensity, and Gut Content Analysis of Mystus tengara. Results of the study revealed that Mystus tengara is a carnivorous fish and zooplankton is the basic food group for this fish species; rotifer has also been observed as the most preferable food class. The species showed isometric growth which indicates the well-being condition of the fish.

Modelling microplastic bioaccumulation and biomagnification potential in the Galápagos penguin ecosystem using Ecopath and Ecosim (EwE) with Ecotracer.

Bioaccumulation and biomagnification of anthropogenic particles are crucial factors in assessing microplastic impacts to marine ecosystems. Microplastic pollution poses a significant threat to iconic and often endangered species but examining their tissues and gut contents for contaminant analysis via lethal sampling is challenging due to ethical concerns and animal care restrictions. Incorporating empirical data from prey items and fecal matter into models can help trace microplastic movement through food webs. In this study, the Galápagos penguin food web served as an indicator species to assess microplastic bioaccumulation and biomagnification potential using trophodynamic Ecopath with Ecosim (EwE) modelling with Ecotracer. Empirical data collected from surface seawater near Galápagos penguin colonies, zooplankton, penguin prey, and penguin scat in October 2021 were used to inform the ecosystem model. Multiple scenarios, including a 99% elimination rate, were employed to assess model sensitivity. Model predictions revealed that microplastics can bioaccumulate in all predator-prey relationships, but biomagnification is highly dependent on the elimination rate. It establishes the need for more research into elimination rates of different plastics, which is a critical missing gap in current microplastic ecotoxicological and bioaccumulation science. Compared to empirical data, modelling efforts underpredicted microplastic concentrations in zooplankton and over-predicted concentrations in fish. Ultimately, the ecosystem modelling provides novel insights into potential microplastics' bioaccumulation and biomagnification risks. These findings can support regional marine plastic pollution management efforts to conserve native and endemic species of the Galápagos Islands and the Galápagos Marine Reserve.