The process of autophagy has been detected in the midgut epithelium of four millipede species: Julus scandinavius, Polyxenus lagurus, Archispirostreptus gigas, and Telodeinopus aoutii. It has been examined using transmission electron microscopy (TEM), which enabled differentiation of cells in the midgut epithelium, and some histochemical methods (light microscope and fluorescence microscope). While autophagy appeared in the cytoplasm of digestive, secretory, and regenerative cells in J. scandinavius and A. gigas, in the two other species, T. aoutii and P. lagurus, it was only detected in the digestive cells. Both types of macroautophagy, the selective and nonselective processes, are described using TEM. Phagophore formation appeared as the first step of autophagy. After its blind ends fusion, the autophagosomes were formed. The autophagosomes fused with lysosomes and were transformed into autolysosomes. As the final step of autophagy, the residual bodies were detected. Autophagic structures can be removed from the midgut epithelium via, e.g., atypical exocytosis. Additionally, in P. lagurus and J. scandinavius, it was observed as the neutralization of pathogens such as Rickettsia-like microorganisms. Autophagy and apoptosis ca be analyzed using TEM, while specific histochemical methods may confirm it.

• Keywords
• Diplopoda, cell death, digestive system, histochemistry, midgut, ultrastructure,
• MeSH
• Apoptosis * MeSH
• Autophagy * MeSH
• Arthropods * MeSH
• Phagosomes ultrastructure   MeSH
• Microscopy, Fluorescence MeSH
• Lysosomes ultrastructure   MeSH
• Microscopy MeSH
• Rickettsia immunology   MeSH
• Intestinal Mucosa immunology   pathology   MeSH
• Microscopy, Electron, Transmission MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH

Ticks are ectoparasites that feed on blood and have an impressive ability to consume and process enormous amounts of host blood, allowing extremely long periods of starvation between blood meals. The central role in the parasitic lifestyle of ticks is played by the midgut. This organ efficiently stores and digests ingested blood and serves as the primary interface for the transmission of tick-borne pathogens. In this study, we used a label-free quantitative approach to perform a novel dynamic proteomic analysis of the midgut of Ixodesricinus nymphs, covering their development from unfed to pre-molt stages. We identified 1534 I. ricinus-specific proteins with a relatively low proportion of host proteins. This proteome dataset, which was carefully examined by manual scrutiny, allowed precise annotation of proteins important for blood meal processing and their dynamic changes during nymphal ontogeny. We focused on midgut molecules related to lipid hydrolysis, storage, and transport, opening a yet unexplored avenue for studying lipid metabolism in ticks. Further dynamic profiling of the tick's multi-enzyme digestive network, protease inhibitors, enzymes involved in redox homeostasis and detoxification, antimicrobial peptides, and proteins responsible for midgut colonization by Borrelia spirochetes promises to uncover new targets for targeting tick nymphs, the most critical life stage for transmission the pathogens that cause tick-borne diseases.

• Keywords
• Borrelia, Ixodes, antimicrobial peptides, label-free quantification, lipid metabolism, midgut, protease inhibitors, proteases, proteome, ticks,
• MeSH
• Ixodes * parasitology   MeSH
• Proteome MeSH
• Proteomics MeSH
• Digestive System MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Proteome MeSH

BACKGROUND: Ticks are obligate hematophagous arthropods transmitting a wide range of pathogens to humans and animals. They also harbor a non-pathogenic microbiota, primarily in the ovaries and the midgut. In the previous study on Ixodes ricinus, we used a culture-independent approach and showed a diverse but quantitatively poor midgut bacterial microbiome. Our analysis also revealed the absence of a core microbiome, suggesting an environmental origin of the tick midgut microbiota. METHODS: A bacterial analysis of the midgut of adult females collected by flagging from two localities in the Czech Republic was performed. Using the culture-independent approach, we tested the hypothesis that the midgut microbiome is of the environmental origin. We also cultured indigenous bacteria from the tick midgut and used these to feed ticks artificially in an attempt to manipulate the midgut microbiome. RESULTS: The midgut showed a very low prevalence and abundance of culturable bacteria, with only 37% of ticks positive for bacteria. The culture-independent approach revealed the presence of Borrelia sp., Spiroplasma sp., Rickettsia sp., Midichloria sp. and various mainly environmental Gram-positive bacterial taxa. The comparison of ticks from two regions revealed that the habitat influenced the midgut bacterial diversity. In addition, the midgut of ticks capillary fed with the indigenous Micrococcus luteus (Gram-positive) and Pantoea sp. (Gram-negative) could not be colonized due to rapid and effective clearance of both bacterial taxa. CONCLUSIONS: The midgut microbiome of I. ricinus is diverse but low in abundance, with the exception of tick-borne pathogens and symbionts. The environment impacts the diversity of the tick midgut microbiome. Ingested extracellular environmental bacteria are rapidly eliminated and are not able to colonize the gut. We hypothesize that bacterial elimination triggered in the midgut of unfed adult females is critical to maintain low microbial levels during blood-feeding.

• Keywords
• Capillary feeding, Culturing, High-throughput sequencing, Ixodes ricinus, Microbiome, Microbiome manipulation, Midgut,
• MeSH
• Borrelia * MeSH
• Ixodes * microbiology   MeSH
• Microbiota * MeSH
• Rickettsia * MeSH
• Animals MeSH
• Check Tag
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Czech Republic epidemiology   MeSH

The midgut epithelia of the millipedes Polyxenus lagurus, Archispirostreptus gigas and Julus scandinavius were analyzed under light and transmission electron microscopies. In order to detect the proliferation of regenerative cells, labeling with BrdU and antibodies against phosphohistone H3 were employed. A tube-shaped midgut of three millipedes examined spreads along the entire length of the middle region of the body. The epithelium is composed of digestive, secretory and regenerative cells. The digestive cells are responsible for the accumulation of metals and the reserve material as well as the synthesis of substances, which are then secreted into the midgut lumen. The secretions are of three types - merocrine, apocrine and microapocrine. The oval or pear-like shaped secretory cells do not come into contact with the midgut lumen and represent the closed type of secretory cells. They possess many electron-dense granules (J. scandinavius) or electron-dense granules and electron-lucent vesicles (A. gigas, P. lagurus), which are accompanied by cisterns of the rough endoplasmic reticulum. The regenerative cells are distributed individually among the basal regions of the digestive cells. The proliferation and differentiation of regenerative cells into the digestive cells occurred in J. scandinavius and A. gigas, while these processes were not observed in P. lagurus. As a result of the mitotic division of regenerative cells, one of the newly formed cells fulfills the role of a regenerative cell, while the second one differentiates into a digestive cell. We concluded that regenerative cells play the role of unipotent midgut stem cells.

• Keywords
• Digestive cells, Midgut epithelium, Millipedes, Regenerative cells, Secretory cells, Ultrastructure,
• MeSH
• Arthropods physiology   ultrastructure   MeSH
• Epithelium metabolism   ultrastructure   MeSH
• Stem Cells physiology   ultrastructure   MeSH
• Digestive System metabolism   ultrastructure   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Czech Republic MeSH

Cimicidae are temporary ectoparasites, which means that they cannot obtain food continuously. Both Cimex species examined here, Cimex lectularius (Linnaeus 1758) and Cimex pipistrelli (Jenyns 1839), can feed on a non-natal host, C. lectularius from humans on bats, C. pipistrelli on humans, but never naturally. The midgut of C. lectularius and C. pipistrelli is composed of three distinct regions-the anterior midgut (AMG), which has a sack-like shape, the long tube-shaped middle midgut (MMG), and the posterior midgut (PMG). The different ultrastructures of the AMG, MMG, and PMG in both of the species examined suggest that these regions must fulfill different functions in the digestive system. Ultrastructural analysis showed that the AMG fulfills the role of storing food and synthesizing and secreting enzymes, while the MMG is the main organ for the synthesis of enzymes, secretion, and the storage of the reserve material. Additionally, both regions, the AMG and MMG, are involved in water absorption in the digestive system of both Cimex species. The PMG is the part of the midgut in which spherites accumulate. The results of our studies confirm the suggestion of former authors that the structure of the digestive tract of insects is not attributed solely to diet but to the basic adaptation of an ancestor.

• Keywords
• Midgut epithelium, alimentary tract, digestive cells, secretory cells,
• MeSH
• Chiroptera MeSH
• Diet MeSH
• Humans MeSH
• Bedbugs anatomy & histology   MeSH
• Feeding Behavior * MeSH
• Digestive System anatomy & histology   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

Culture-independent metagenomic methodologies have enabled detection and identification of microorganisms in various biological systems and often revealed complex and unknown microbiomes. In many organisms, the microbiome outnumbers the host cells and greatly affects the host biology and fitness. Ticks are hematophagous ectoparasites with a wide host range. They vector a number of human and animal pathogens and also directly cause major economic losses in livestock. Although several reports on a tick midgut microbiota show a diverse bacterial community, in most cases the size of the bacterial population has not been determined. In this study, the microbiome was quantified in the midgut and ovaries of the ticks Ixodes ricinus and Rhipicephalus microplus before, during, and after blood feeding. Although the size of bacterial community in the midgut fluctuated with blood feeding, it was overall extremely low in comparison to that of other hematophagous arthropods. In addition, the tick ovarian microbiome of both tick species exceeded the midgut 16S rDNA copy numbers by several orders of magnitude. This indicates that the ratio of a tick midgut/ovary microbiome represents an exception to the general biology of other metazoans. In addition to the very low abundance, the tick midgut diversity in I. ricinus was variable and that is in contrast to that found in the tick ovary. The ovary of I. ricinus had a very low bacterial diversity and a very high and stable bacterial abundance with the dominant endosymbiont, Midichloria sp. The elucidation of this aspect of tick biology highlights a unique tissue-specific microbial-invertebrate host interaction.

• Keywords
• symbiosis, Ixodes ricinus, Midichloria mitochondrii, Rhipicephalus microplus, midgut microbiome, ovary microbiome, tick,
• MeSH
• Ixodidae * MeSH
• Ixodes * MeSH
• Humans MeSH
• Microbiota * MeSH
• Ovary MeSH
• Rhipicephalus * MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Three types of cells have been distinguished in the midgut epithelium of two centipedes, Lithobius forficatus and Scolopendra cingulata: digestive, secretory, and regenerative cells. According to the results of our previous studies, we decided to analyze the relationship between apoptosis and necrosis in their midgut epithelium and circadian rhythms. Ultrastructural analysis showed that these processes proceed in a continuous manner that is independent of the circadian rhythm in L. forficatus, while in S. cingulata necrosis is activated at midnight. Additionally, the description of apoptosis and necrosis showed no differences between males and females of both species analyzed. At the beginning of apoptosis, the cell cytoplasm becomes electron-dense, apparently in response to shrinkage of the cell. Organelles such as the mitochondria, cisterns of endoplasmic reticulum transform and degenerate. Nuclei gradually assume lobular shapes before the apoptotic cell is discharged into the midgut lumen. During necrosis, however, the cytoplasm of the cell becomes electron-lucent, and the number of organelles decreases. While the digestive cells of about 10 % of L. forficatus contain rickettsia-like pathogens, the corresponding cells in S. cingulata are free of rickettsia. As a result, we can state that apoptosis in L. forficatus is presumably responsible for protecting the organism against infections, while in S. cingulata apoptosis is not associated with the elimination of pathogens. Necrosis is attributed to mechanical damage, and the activation of this process coincides with proliferation of the midgut regenerative cells at midnight in S. cingulata.

• Keywords
• Cell death, Centipede, Digestive cells, Midgut epithelium, Ultrastructure,
• MeSH
• Apoptosis * MeSH
• Circadian Rhythm MeSH
• Arthropods cytology   microbiology   MeSH
• Epithelial Cells microbiology   physiology   ultrastructure   MeSH
• DNA Fragmentation MeSH
• Necrosis * MeSH
• Digestive System cytology   microbiology   MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

Ticks are obligate hematophagous arthropods that transmit a wide range of pathogens to humans as well as wild and domestic animals. They also harbor a non-pathogenic microbiota, although our previous study has shown that the diverse bacterial microbiome in the midgut of Ixodes ricinus is quantitatively poor and lacks a core. In artificial infections by capillary feeding of ticks with two model bacteria (Gram-positive Micrococcus luteus and Gram-negative Pantoea sp.), rapid clearance of these microbes from the midgut was observed, indicating the presence of active immune mechanisms in this organ. In the current study, RNA-seq analysis was performed on the midgut of I. ricinus females inoculated with either M. luteus or Pantoea sp. or with sterile water as a control. While no immune-related transcripts were upregulated by microbial inoculation compared to that of the sterile control, capillary feeding itself triggered dramatic transcriptional changes in the tick midgut. Manual curation of the transcriptome from the midgut of unfed I. ricinus females, complemented by the proteomic analysis, revealed the presence of several constitutively expressed putative antimicrobial peptides (AMPs) that are independent of microbial stimulation and are referred to here as 'guard' AMPs. These included two types of midgut-specific defensins, two different domesticated amidase effector 2 (Dae2), microplusin/ricinusin-related molecules, two lysozymes, and two gamma interferon-inducible lysosomal thiol reductases (GILTs). The in vitro antimicrobial activity assays of two synthetic mature defensins, defensin 1 and defensin 8, confirmed their specificity against Gram-positive bacteria showing exceptional potency to inhibit the growth of M. luteus at nanomolar concentrations. The antimicrobial activity of midgut defensins is likely part of a multicomponent system responsible for the rapid clearance of bacteria in the tick midgut. Further studies are needed to evaluate the role of other identified 'guard' AMPs in controlling microorganisms entering the tick midgut.

• Keywords
• Ixodes, Micrococcus luteus, antimicrobial peptide, defensin, immune system, midgut microbiome, tick,
• MeSH
• Antimicrobial Peptides metabolism   MeSH
• Gastrointestinal Tract microbiology   immunology   MeSH
• Ixodes * microbiology   immunology   MeSH
• Micrococcus luteus immunology   MeSH
• Proteomics MeSH
• Gene Expression Profiling MeSH
• Transcriptome MeSH
• Animals MeSH
• Check Tag
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Antimicrobial Peptides MeSH

The midgut epithelium of two centipedes, Lithobius forficatus and Scolopendra cingulata, is composed of digestive, secretory and regenerative cells. In L. forficatus, the autophagy occurred only in the cytoplasm of the digestive cells as a sporadic process, while in S. cingulata, it occurred intensively in the digestive, secretory and regenerative cells of the midgut epithelium. In both of the species that were analyzed, this process proceeded in a continuous manner and did not depend on the day/night cycle. Ultrastructural analysis showed that the autophagosomes and autolysosomes were located mainly in the apical and perinuclear cytoplasm of the digestive cells in L. forficatus. However, in S. cingulata, the entire cytoplasm was filled with autophagosomes and autolysosomes. Initially the membranes of phagophores surround organelles during autophagosome formation. Autolysosomes result from the fusion of autophagosomes and lysosomes. Residual bodies which are the last stage of autophagy were released into the midgut lumen due to necrosis. Autophagy in the midgut epithelia that were analyzed was confirmed using acid phosphatase and mono-dansyl-cadaverine stainings.

• Keywords
• Autophagy, Centipede, Digestive cells, Midgut epithelium, Ultrastructure,
• MeSH
• Autophagy * MeSH
• Circadian Rhythm * MeSH
• Arthropods cytology   physiology   MeSH
• Cytoplasm ultrastructure   MeSH
• Epithelial Cells physiology   ultrastructure   MeSH
• Phagosomes ultrastructure   MeSH
• Photoperiod * MeSH
• Gastrointestinal Tract physiology   MeSH
• Lysosomes ultrastructure   MeSH
• Intestinal Mucosa physiology   MeSH
• Microscopy, Electron, Transmission MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH

INTRODUCTION: Malrotation is understood as a congenital anomaly of the intestinal position formed during embryonic development. Disorders of intestinal rotation and its manifestations in adulthood are less common; the symptoms of these disorders are characteristic of childhood. An asymptomatic bowel rotation disorder occurs in up to 1 of 200 newborns and symptomatic malrotation occurs in 1 of 6,000 live newborns. The incidence of intestinal rotation disorders in adulthood is estimated to be between 0.0001% and 0.19%. Acute complications in adulthood include volvulus with ischemia of the small bowel. CASE REPORT: A 36-year-old man with a previously diagnosed bowel rotation disorder with intermittent abdominal pain was examined for sudden convulsive pain. The CT scan showed volvulus of small bowel. During surgery, a small bowel volvulus with venostasis and dilated mesenteric veins rotated 360 degrees clockwise, the mesenterium commune, and the presence of Ladds bands causing partial compression of the duodenum were found. The condition was managed surgically to derotate the loops into nonrotation with preserved viability of the intestinal loops, interrupt the Ladds bands and mobilize the duodenum, including fixation of the mesentery to the retroperitoneum and invagination appendectomy. The patient has been without problems and without any signs of complications based on his 2-year follow-up from the surgery. CONCLUSION: Early surgical treatment of intestinal malrotation complications helps maintain intestinal viability and can prevent the development of the short bowel post-resection syndrome. Prophylactic surgery should be considered in symptomatic rotation disorders, although the determination of the indication for surgery and its timing remain uncertain.

• Keywords
• adult − midgut − malrotation − acute abdomen,
• MeSH
• Appendectomy MeSH
• Adult MeSH
• Duodenum MeSH
• Humans MeSH
• Infant, Newborn MeSH
• Intestines MeSH
• Intestine, Small MeSH
• Intestinal Volvulus * complications   diagnostic imaging   surgery   MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Male MeSH
• Infant, Newborn MeSH
• Publication type
• Journal Article MeSH
• Case Reports MeSH