Exploring the midgut physiology of the non-haematophagous mosquito Toxorhynchites theobaldi.

Toxorhynchites mosquitoes have an exclusively phytophagous feeding habit as adults, which leads to significant differences in their morphophysiology compared with haematophagous mosquitoes. However, the molecular mechanisms of digestion in this mosquito are not well understood. In this study, RNA sequencing of the posterior midgut (PMG) of the mosquito Toxorhynchites theobaldi was undertaken, highlighting its significance in mosquito digestion. Subsequently, a comparison was made between the differential gene expression of the PMG and that of the anterior midgut. It was found that the most abundant proteases in the PMG were trypsin and chymotrypsin, and the level of gene expression for enzymes essential for digestion (such as serine protease, α-amylase and pancreatic triacylglycerol lipase) and innate immune response (including catalase, cecropin-A2 and superoxide dismutase) was like that of haematophagous mosquitoes. Peritrophin-1 was detected in the entire midgut, with an elevated expression level in the PMG. Based on our findings, it is hypothesized that a non-haematophagic habit might have been exhibited by the ancestor of Tx. theobaldi, and this trait may have been retained. This study represents a pioneering investigation at the molecular level of midgut contents in a non-haematophagous mosquito. The findings offer valuable insights into the evolutionary aspects of feeding habits in culicids.

Nano titanium dioxide alleviates the toxic effects of tris (2-chloropropyl) phosphate on the digestive gland and hemolymph of thick-shell mussel Mytilus coruscus.

In the marine environment, nanoparticles play a role in adsorbing and catalytically degrading organic pollutants, thereby mitigating their toxic effects on aquatic organisms. This study aimed to investigate the impact of nano titanium dioxide (nTiO2) and tris (2-chloropropyl) phosphate (TCPP) on the hemolymph and digestive function of the thick-shell mussel Mytilus coruscus. Mussels were divided into a control group, a group exposed to TCPP alone, a group exposed to a combination of TCPP and 0.5 mg/L nTiO2, and a group exposed to a combination of TCPP and 1 mg/L nTiO2. After 14 days of exposure, oxidative stress responses, including superoxide dismutase (SOD) activity and malondialdehyde (MDA) content, immune defense responses, including acid phosphatase (ACP) and alkaline phosphatase (AKP) activities, and gene expression, including HSP70 expression, were measured in the hemolymph and digestive glands of the mussels. Compared to the control group, mussels solely exposed to 100 µg/L TCPP exhibited a significant reduction in SOD activity in the hemolymph. When TCPP was co-exposed with 0.5 mg/L nTiO2, there were significant increases in MDA content and AKP activity in both the digestive gland and hemolymph compared to the control group. Upon co-exposure of TCPP with 1 mg/L nTiO2, MDA content and AKP activity in the digestive gland significantly decreased, while SOD, ACP, and AKP activity in the hemolymph significantly increased and MDA content significantly decreased, returning to the control group levels. Furthermore, in the combined exposure, HSP70 gene expression significantly decreased as the nTiO2 concentration increased from 0.5 mg/L to 1 mg/L. In summary, TCPP impacted the hemolymph and digestive function of mussels, whereas a concentration of 1 mg/L nTiO2 effectively alleviated the toxic effects of TCPP. This study is crucial for assessing the ecological risks of nanoparticles and emerging organic pollutants in marine environments, and provides new insights into the interaction between nTiO2 and TCPP, as well as the influence of nTiO2 concentration on mitigating TCPP toxicity.

The Role and Function of TRPM8 in the Digestive System.

Transient receptor potential (TRP) melastatin member 8 (TRPM8) is a non-selective cation channel that can be activated by low temperatures (8-26 °C), cooling agents (including menthol analogs such as menthol, icilin, and WS-12), voltage, and extracellular osmotic pressure changes. TRPM8 expression has been identified in the digestive system by several research teams, demonstrating its significant involvement in tissue function and pathologies of the digestive system. Specifically, studies have implicated TRPM8 in various physiological and pathological processes of the esophagus, stomach, colorectal region, liver, and pancreas. This paper aims to comprehensively outline the distinct role of TRPM8 in different organs of the digestive system, offering insights for future mechanistic investigations of TRPM8. Additionally, it presents potential therapeutic targets for treating conditions such as digestive tract inflammation, tumors, sensory and functional disorders, and other related diseases. Furthermore, this paper addresses the limitations of existing studies and highlights the research prospects associated with TRPM8.

Midgut morphology of the predator mosquito Lutzia bigoti (Diptera: Culicidae) and its implications for feeding behavior.

Lutzia mosquitoes (Theobald, 1903) are predaceous during their larval stages, but the adult feeding is not clearly understood, especially in relation to blood feeding. In case these mosquitoes are harmless to humans and related animals, they can be useful in biological control of mosquito vectors of pathogens. Investigating the midgut morphology is a good strategy to understand the feeding behavior of this species. The midgut in Lutzia bigoti Bellardi, 1862 displays two distinct portions, a thin anterior midgut and a more dilated posterior midgut. Digestive cells form a single epithelium in the midgut. These cells have long and packed microvilli at their apex and membrane infoldings at their basal portion, the basal labyrinth. The epithelium is supported by a basal lamina. Regarding their cytoplasm, it is noteworthy the abundance of mitochondria, distributed in an apical-basal fashion, and also a whirl-shaped endoplasmic reticulum in the posterior midgut. Basal cells are also found in the midgut of L. bigoti, resembling regenerative cells. The general organization of L. bigoti's midgut closely resembles that of numerous hematophagous mosquitoes previously documented. However, it diverges due to the presence of a peritrophic matrix even when exclusively fed on sugary solutions. Peculiar aspects of L. bigoti's midgut are discussed and compared to those of other mosquito species.

A cell atlas of the adult female Aedes aegypti midgut revealed by single-cell RNA sequencing.

Aedes aegypti is a primary vector for transmitting various arboviruses, including Yellow fever, dengue and Zika virus. The mosquito midgut is the principal organ for blood meal digestion, nutrient absorption and the initial site of arbovirus infection. Although a previous study delineated midgut's transcriptome of Ae. aegypti at the single-nucleus resolution, there still lacks an established protocol for isolating and RNA sequencing of single cells of Ae. aegypti midgut, which is required for investigating arbovirus-midgut interaction at the single-cell level. Here, we established an atlas of the midgut cells for Ae. aegypti by single-cell RNA sequencing. We annotated the cell clusters including intestinal stem cells/enteroblasts (ISC/EB), cardia cells (Cardia), enterocytes (EC, EC-like), enteroendocrine cells (EE), visceral muscle (VM), fat body cells (FBC) and hemocyte cells (HC). This study will provide a foundation for further studies of arbovirus infection in mosquito midgut at the single-cell level.

Exposure to low-concentration fipronil impairs survival, behavior, midgut morphology and physiology of Aedes aegypti larvae.

The Aedes aegypti mosquito is a vector for various arboviruses, including dengue and yellow fever. Insecticides, such as pyrethroids and organophosphates, are widely used to manage and control these insects. However, mosquitoes have developed resistance to these chemicals. Therefore, this study aimed to investigate the effects of the commercial formulation of fipronil (Tuit® Florestal; 80% purity) on the survival, behavior, morphology, and proteins related to signaling pathways of the midgut in A. aegypti larvae under controlled laboratory conditions. Significant reductions in immature survival were observed in all concentrations of fipronil tested. Low insecticide concentration (0.5 ppb) led to decreased locomotor activity in the larvae and caused disorganization of the epithelial tissue in the midgut. Moreover, exposure to the insecticide decreased the activity of detoxifying enzymes such as catalase, superoxide dismutase, and glutathione-S-transferase. On the other hand, the insecticide increased protein oxidation and nitric oxide levels. The detection of LC3, caspase-3, and JNK proteins, related to autophagy and apoptosis, increased after exposure. However, there was a decrease in the positive cells for ERK 1/2. Furthermore, the treatment with fipronil decreased the number of positive cells for the proteins FMRF, Prospero, PH3, Wg, Armadillo, Notch, and Delta, which are related to cell proliferation and differentiation. These findings demonstrate that even at low concentrations, fipronil exerts larvicidal effects on A. aegypti by affecting behavior and enzymatic detoxification, inducing protein oxidation, free radical generation, midgut damage and cell death, and inhibiting cell proliferation and differentiation. Thus, this insecticide may represent a viable alternative for controlling the spread of this vector.

In vitro digestion of microplastics in human digestive system: Insights into particle morphological changes and chemical leaching.

Despite the well-reported occurrences and established pathways for microplastics (MPs) ingestion by humans, the eventual fate of these particles in the human gastrointestinal system is poorly understood. The present study tries to gain a better understanding of the fate of four common food-borne MPs, i.e. Polystyrene (PS), Polypropylene (PP), Low-density Polyethylene (LDPE), and Nylon, in a simulated in vitro human digestive system. Firstly, the changes in the physicochemical properties of 20-210 µm sized MPs as well as the leaching of chemicals were monitored using fluorescence microscopy, FTIR, and LC-QTOF-MS. Thereafter, the mass loss and morphological alterations in 3-4 mm sized MPs were observed after removing the organic matter. The interaction of PS and PP MPs with duodenal and bile juices manifested in a corona formation. The increase in surface roughness in PP MPs aligned with MP-enzyme dehydrogenation reactions and the addition of NO groups. A few fragments ranging from 30 to 250 µm, with negligible mass loss, were released during the MP digestion process. In addition, the leaching of compounds, e.g. capsi-amide, butanamide, and other plasticizers and monomers was also observed from MPs during digestion, and which may have the potential to accumulate and get absorbed by the digestive organs, and to subsequently impart toxic effects.

The organisation of the digestive, excretory and reproductive systems in cysts of the freshwater tardigrade Thulinius ruffoi (Parachela, Isohypsibioidea: Doryphoribiidae).

Tardigrades are invertebrates known to science for over 250 years. Although the ability of some species of tardigrades to form cysts has been reported, little is known about the encystment and internal organisation of the cysts. During cyst formation, contraction of the body affects the internal organs' morphology. The organs are compressed and have a compact appearance. The organisation of the digestive system, associated structures, and the reproductive system are analysed in cysts on indefinite and well-defined encystment periods - up to eleven months. The digestive system of encysted animals was organised into three main parts - a foregut, a midgut, and a hindgut. The presence of digestive system-associated structures, such as buccal glands or muscles, was noted and described. The excretory organs, called Malpighian tubules, open into the zone between the midgut and the hindgut. Furthermore, the oviduct opens into the hindgut. The first analysis of the reproductive system of cysts at the ultrastructural level is presented here, revealing interesting and undescribed aspects related to the physiology. Besides the anatomical and histological examination, the morphology and changes that occur during cyst formation are described.

Differential expression of neuropeptide F in the digestive organs of female freshwater prawn, Macrobrachium rosenbergii, during the ovarian cycle.

Neuropeptide F is a key hormone that controls feeding in invertebrates, including decapod crustaceans. We investigated the differential expression of Macrobrachium rosenbergii neuropeptide F (MrNPF) in the digestive organs of female prawns, M. rosenbergii, during the ovarian cycle. By using RT-qPCR, the expression of MrNPF mRNA in the esophagus (ESO), cardia (CD), and pylorus (PY) of the foregut (FG) gradually increased from stage II and peaked at stage III. In the midgut (MG), hindgut (HG), and hepatopancreas (HP), MrNPF mRNA increased from stage I, reaching a maximal level at stage II, and declined by about half at stages III and IV (P < 0.05). In the ESO, CD, and PY, strong MrNPF-immunoreactivities were seen in the epithelium, muscle, and lamina propria. Intense MrNPF-ir was found in the MG cells and the muscular layer. In the HG, MrNPF-ir was detected in the epithelium of the villi and gland regions, while MrNPF-ir was also more intense in the F-, R-, and B-cells in the HP. However, we found little colocalization between the MrNPF and PGP9.5/ChAT in digestive tissues, implying that most of the positive cells might not be neurons but could be digestive tract-associated endocrine cells that produce and secrete MrNPF to control digestive organ functions in feeding and utilizing feed. Taken together, our first findings indicated that MrNPF was differentially expressed in digestive organs in correlation with the ovarian cycle, suggesting an important link between MrNPF, the physiology of various digestive organs in feeding, and possibly ovarian maturation in female M. rosenbergii.

Microplastics in the Indian and South Atlantic oceans translocate to gills, digestive glands, and muscle of the chokka squid Loligo reynaudii.

Comparative microplastic (MP) data for cephalopods between oceans is scarce. Our aim was to quantify, characterise, and compare MPs in gills, digestive gland, and mantle of chokka squid from the South Atlantic Ocean (SAO) and Indian Ocean (IO) off the coast of South Africa. South African squid had more MPs compared with other studies (means = 2.0 and 0.4 in SAO and IO squid mantle, respectively). Blue fibres were dominant. Identifiable MPs were polyethylene. Despite IO water having higher MP concentrations than the SAO, SAO squid had higher MP concentrations. Dilution by growth is the likely reason for the lower MP concentrations. Fibres were shorter in SAO than IO squid. However, we could not explain why fibre and mantle lengths from both oceans were positively correlated. Squid may not be the best indicator of marine MPs. The characteristics of MPs in squid can be used to track stocks and migrations.

Exposure to environmental pharmaceuticals affects the macromolecular composition of mussels digestive glands.

Human pharmaceuticals represent a major challenge in natural environment. A better knowledge on their mechanisms of action and adverse effects on cellular pathways is fundamental to predict long-term consequences for marine wildlife. The FTIRI Imaging (FTIRI) spectroscopy represents a vibrational technique allowing to map specific areas of non-homogeneous biological samples, providing a unique biochemical and ultrastructural fingerprint of the tissue. In this study, FTIRI technique has been applied, for the first time, to characterize (i) the chemical building blocks of digestive glands of Mytilus galloprovincialis, (ii) alterations and (iii) resilience of macromolecular composition, after a 14-days exposure to 0.5 µg/L of carbamazepine (CBZ), valsartan (VAL) and their mixture, followed by a 14-days recovery period. Spectral features of mussels digestive glands provided insights on composition and topographical distribution of main groups of biological macromolecules, such as proteins, lipids, and glycosylated compounds. Pharmaceuticals caused an increase in the total amount of protein and a significant decrease of lipids levels. Changes in macromolecular features reflected the modulation of specific molecular and biochemical pathways thus supporting our knowledge on mechanisms of action of such emerging pollutants. Overall, the applied approach could represent an added value within integrated strategies for the effects-based evaluation of environmental contaminants.

RNA interference-mediated silencing of coat protein II (COPII) genes affects the gut homeostasis and cuticle development in Locusta migratoria.

The coat protein II (COPII) complex consists of five primary soluble proteins, namely the small GTP-binding protein Sar1, the inner coat Sec23/Sec24 heterodimers, and the outer coat Sec13/Sec31 heterotetramers. COPII is essential for cellular protein and lipid trafficking through cargo sorting and vesicle formation at the endoplasmic reticulum. However, the roles of COPII assembly genes remain unknown in insects. In present study, we identified five COPII assembly genes (LmSar1, LmSec23, LmSec24, LmSec13 and LmSec31) in Locusta migratoria. RT-qPCR results revealed that these genes showed different expression patterns in multiple tissues and developmental days of fifth-instar nymphs. Injection of double-stranded RNA against each LmCOPII gene induced a high RNAi efficiency, and considerably suppressed feeding, and increased mortality to 100 %. Results from the micro-sectioning and hematoxylin-eosin staining of midguts showed that the brush border was severely damaged and the number of columnar cells was significantly reduced in dsLmCOPII-injected nymphs, as compared with the control. The dilated endoplasmic reticulum phenotype of columnar cells was observed by transmission electron microscopy. RT-qPCR results further indicated that silencing any of the five genes responsible for COPII complex assembly repressed the expression of genes involved in insulin/mTOR-associated nutritional pathway. Therefore, COPII assembly genes could be promising RNAi targets for insect pest management by disrupting gut and cuticle development.

Role of Food Digestion and Digestive System in the Nutritional, Functional and Health Properties of Food Bioactives.

The impact of food components on the human digestive system is an important area of research in the fields of nutrition and food science [...].

[Dietary management of the Parkinson's patient: a necessity at every stage of the digestive system]. / Prise en charge diététique du patient parkinsonien : une nécessité à chaque étape du système digestif.

Nutrition is a recurrent theme in the care of patients with Parkinson's disease. The aim of this article is to focus on the nutritional problems encountered in this pathology, and to clarify the role of the dietician in its management.

Quantitative Analysis of Bioaccessible Phenolic Compounds in Aegean Bee Bread Using LC-HRMS Coupled with a Human Digestive System Model.

Bee bread, a valuable bee product that has recently attracted significant public interest as a nutritional supplement. The aim of this study was to evaluate the presence of phenolic compounds in bee bread samples from the Aegean Region and assess their bioaccessibility using a simulated human digestion model. Various extraction techniques, such as maceration, ultrasound-assisted extraction, and supercritical fluid extraction were employed to obtain extracts of bee bread. The antioxidant capabilities of these extracts were carried out using assays like DPPH⋅, ABTS⋅+ , CUPRAC, and ß-carotene linoleic acid bleaching, and their effectiveness was quantified through IC50 values. The bioaccessibility of phenolic compounds was analysed by using LC-HRMS in a simulated human digestive system using ethanol extracts obtained from bee bread samples of each season by ultrasound-assisted extraction, which has the highest antioxidant activity. In the Aegean bee bread, a total of 25 phenolic compounds which were major phenolics including quercetin, ascorbic acid, isorhamnetin, kaempferol, and hyperoside were identified and quantified. Also, ascorbic acid was the one of the most bioaccessible compounds with the bioaccessibility index 35.38 % for 2021, 16.79 % for 2022. These findings underscore the substantial transformation of the phenolic profile of bee bread as it traverses the human digestive system.

Diagnostic Challenges during Inflammation and Cancer: Current Biomarkers and Future Perspectives in Navigating through the Minefield of Reactive versus Dysplastic and Cancerous Lesions in the Digestive System.

In the setting of pronounced inflammation, changes in the epithelium may overlap with neoplasia, often rendering it impossible to establish a diagnosis with certainty in daily clinical practice. Here, we discuss the underlying molecular mechanisms driving tissue response during persistent inflammatory signaling along with the potential association with cancer in the gastrointestinal tract, pancreas, extrahepatic bile ducts, and liver. We highlight the histopathological challenges encountered in the diagnosis of chronic inflammation in routine practice and pinpoint tissue-based biomarkers that could complement morphology to differentiate reactive from dysplastic or cancerous lesions. We refer to the advantages and limitations of existing biomarkers employing immunohistochemistry and point to promising new markers, including the generation of novel antibodies targeting mutant proteins, miRNAs, and array assays. Advancements in experimental models, including mouse and 3D models, have improved our understanding of tissue response. The integration of digital pathology along with artificial intelligence may also complement routine visual inspections. Navigating through tissue responses in various chronic inflammatory contexts will help us develop novel and reliable biomarkers that will improve diagnostic decisions and ultimately patient treatment.

Clogmia albipunctata (Williston, 1893) midgut physiology: pH control and functional relationship with Lower Diptera (nematoceran) especially with hematophagous species.

Clogmia albipunctata (Williston, 1893) is a non-hematophagous insect belonging to the order Diptera, suborder Nematocera (Lower Diptera) and family Psychodidae. In the present work, we investigated how C. albipunctata control their midgut pH under different physiological conditions, comparing their midgut physiology with some nematoceran hematophagous species. The C. albipunctata midgut pH was measured after ingestion of sugar, protein and under the effect of the alkalinizing hormone released in the hemolymph of the hematophagous sand fly Lutzomyia longipalpis obtained just after a blood meal. The midgut pH of unfed or sugar-fed C. albipunctata is 5.5-6, and its midgut underwent alkalinization after protein ingestion or under treatment with hemolymph collected from blood fed L. longipalpis. These results suggested that in nematocerans, mechanisms for pH control seem shared between hematophagous and non-hematophagous species. This kind of pH control is convenient for successful blood digestion. The independent evolution of many hematophagous groups from the Lower Diptera suggests that characteristics involved in midgut pH control were already present in non-hematophagous species and represent a readiness for adaptation to this feeding mode.

Proteotranscriptomic analyses of the midgut and Malpighian tubules after a sublethal concentration of Cry1Ab exposure on Spodoptera litura.

BACKGROUND: Cry1Ab has emerged as a bio-insecticide to control Spodoptera litura (Lepidoptera: Noctuidae). However, the sublethal effects of Cry1Ab on the physiological changes and molecular level of S. litura have not been well documented. Our aims in this study were to assess the sublethal effect of Cry1Ab on S. litura, including midgut and Malpighian tubules as targets. RESULTS: After sublethal Cry1Ab exposure, distinct histological alterations were mainly observed in the midgut. Furthermore, the results of comparative RNA sequencing and tandem mass tag-based proteomics showed that, in the midgut, most differential expression genes (DEGs) were up-regulated and significantly enriched in the serine protease activity pathway, and up-regulated differential expression proteins (DEPs) were mainly associated with the oxidative phosphorylation pathway, whereas the down-regulated involved in the ribosome pathways. In the Malpighian tubules, DEGs and DEPs were significantly enriched in the ribosome pathway. We proposed that ribosome may act as a universal target in energy metabolism with other pathways via the results of protein-protein interaction analysis. Further, by verification of the mRNA expression of some Cry protein receptor and detoxification genes after Cry1Ab treatment, it was suggested that the ribosomal proteins (RPs) possibly participate in influencing the Bt-resistance of S. litura larvae under sublethal Cry1Ab exposure. CONCLUSION: Under sublethal Cry1Ab exposure, the midgut of S. litura was damaged, and the proteotranscriptomic analysis elucidated that Cry1Ab disrupted the energy homeostasis of larvae. Furthermore, we emphasized the potential role of ribosomes in sublethal Cry1Ab exposure. © 2024 Society of Chemical Industry.

Endoscopist experience with pediatric recurrent and intentional foreign body ingestion (RIFBI): Management considerations and future directions.

OBJECTIVES AND STUDY: Accidental foreign body ingestion (FBI) is a common pediatric referral concern. In contrast, recurrent and intentional FBI (RIFBI) is infrequent and associated with greater endoscopic and surgical intervention in adults. Although pediatric guidelines exist for FBI, the risk and therapeutic implications of RIFBI are not addressed. An anonymous international survey on pediatric gastroenterologist experience with RIFBI was distributed. METHODS: A 33-item REDCap© survey was distributed via email to pediatric gastroenterologists identified through mailing and email lists obtained from pediatric gastroenterology professional organizations. RESULTS: During 9-12/2021 we accrued 202 completed surveys. Respondents were from 27 countries and across the career span. Eighty percent reported experience with RIFBI; 74% reported seeing ≤ 3 patients with RIFBI within the past 24 months and 4% reported seeing ≥ 6. Of those who treated RIFBI, 38% reported an average number of annual ingestions per patient was ≥5. Frequent morbidity but not mortality was reported. Half reported adherence to FBI guidelines. Later-career endoscopists treated RIFBI more aggressively than accidental ingestion. Ninety-six percent noted that patients with RIFBI had psychiatric comorbidities. Providers at academic medical centers reported referring to behavioral health more than those in other settings. CONCLUSION: Most gastroenterologists surveyed reported encountering RFBI several times a year and in patients with psychiatric comorbidities. Greater likelihood of adverse outcomes associated with endoscopy was reported. Most reported referral to behavioral health and few had RIFBI management protocols. A broader spectrum of psychologic comorbidities in the pediatric population with RIFBI, notably depression and autism spectrum disorder, were reported.