Ultrastructure of the Bacteriocytes in the Midgut of the Carpenter ant Camponotus rufipes: Endosymbiont Control by Autophagy

2020 ◽  
Vol 26 (6) ◽  
pp. 1236-1244
Author(s):  
Wagner G. Gonçalves ◽  
Kenner M. Fernandes ◽  
Ana Paula A. Silva ◽  
Danilo G. Gonçalves ◽  
Muhammad Fiaz ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Midgut Epithelium ◽  
Intracellular Bacteria ◽  
Digestive Cells ◽  
Cellular Events ◽  
Carpenter Ant ◽  
Intermediate Morphology ◽  
Autophagy Pathway ◽  
Camponotus Rufipes ◽  
Intermediate Cells

AbstractThe carpenter ant Camponotus rufipes has intracellular bacteria in bacteriocytes scattered in the midgut epithelium, which have different amounts of endosymbionts, according to the developmental stages. However, there are no detailed data about the midgut cells in adult workers. The present work aimed to evaluate the morphology and cellular events that coordinate the abundance of endosymbionts in the midgut cells in C. rufipes workers. The midgut epithelium has digestive cells, bacteriocytes, and cells with intermediate morphology. The latter is similar to bacteriocytes, due to the abundance of endosymbionts, and similar to digestive cells, due to their microvilli. The digestive and intermediate cells are rich in autophagosomes and autolysosomes, both with bacteria debris in the lumen. These findings suggest that midgut cells of C. rufipes control the endosymbiont level by the autophagy pathway.

Autophagy and Apoptosis in the Midgut Epithelium of Millipedes

2019 ◽  
Vol 25 (4) ◽  
pp. 1004-1016 ◽  
Author(s):  
M.M. Rost-Roszkowska ◽  
J. Vilimová ◽  
K. Tajovský ◽  
A. Chachulska-Żymełka ◽  
A. Sosinka ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Microscope ◽  
Fluorescence Microscope ◽  
Midgut Epithelium ◽  
Digestive Cells ◽  
Histochemical Methods ◽  
Transmission Electron ◽  
Regenerative Cells ◽  
Residual Bodies

AbstractThe 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.

Neural Transcription Correlates of Multimodal Cortical Phenotypes during Development

2019 ◽  
Vol 30 (5) ◽  
pp. 2740-2754 ◽  
Author(s):  
Diliana Pecheva ◽  
Annie Lee ◽  
Joann S Poh ◽  
Yap-Seng Chong ◽  
Lynette P Shek ◽  
...  
Keyword(s):  
Gene Expression ◽  
Developmental Stages ◽  
Cell Types ◽  
Cellular Events ◽  
Genetic Mechanisms ◽  
Magnetic Resonance Imaging Mri ◽  
Regulated Gene Expression ◽  
Genetic Signatures ◽  
Cell Migration And Proliferation

Abstract During development, cellular events such as cell proliferation, migration, and synaptogenesis determine the structural organization of the brain. These processes are driven in part by spatiotemporally regulated gene expression. We investigated how the genetic signatures of specific neural cell types shape cortical organization of the human brain throughout infancy and childhood. Using a transcriptional atlas and in vivo magnetic resonance imaging (MRI) data, we demonstrated time-dependent associations between the expression levels of neuronal and glial genes and cortical macro- and microstructure. Neonatal cortical phenotypes were associated with prenatal glial but not neuronal gene expression. These associations reflect cell migration and proliferation during fetal development. Childhood cortical phenotypes were associated with neuronal and astrocyte gene expression related to synaptic signaling processes, reflecting the refinement of cortical connections. These findings indicate that sequential developmental stages contribute to distinct MRI measures at different time points. This helps to bridge the gap between the genetic mechanisms driving cellular changes and widely used neuroimaging techniques.

scholarly journals Elevated Hoxb5b expands vagal neural crest pool and blocks enteric neuronal development in zebrafish

2021 ◽  
Author(s):  
Aubrey G. Adam Howard ◽  
Aaron C Nguyen ◽  
Joshua Tworig ◽  
Priya Ravisankar ◽  
Eileen Willey Singleton ◽  
...  
Keyword(s):  
Neural Crest ◽  
Neuronal Development ◽  
Developmental Stages ◽  
Stem Cell Population ◽  
Transgenic Zebrafish ◽  
Cellular Events ◽  
Comprehensive Knowledge ◽  
Numerous Cell ◽  
Timely Fashion ◽  
Adult Organism

Neural crest cells (NCCs) are a migratory, transient, and multipotent stem cell population essential to vertebrate embryonic development, contributing to numerous cell lineages in the adult organism. While great strides have been made in elucidating molecular and cellular events that drive NCC specification, comprehensive knowledge of the genetic factors that orchestrate NCC developmental programs is still far from complete. We discovered that elevated Hoxb5b levels promoted an expansion of zebrafish NCCs, which persisted throughout multiple stages of development. Correspondingly, elevated Hoxb5b also specifically expanded expression domains of the vagal NCC markers foxd3 and phox2bb. Increases in NCCs were most apparent after pulsed ectopic Hoxb5b expression at early developmental stages, rather than later during differentiation stages, as determined using a novel transgenic zebrafish line. The increase in vagal NCCs early in development led to supernumerary Phox2b+ enteric neural progenitors, while leaving many other NCC-derived tissues without an overt phenotype. Surprisingly, these NCC-derived enteric progenitors failed to expand properly into sufficient quantities of enterically fated neurons and stalled in the gut tissue. These results suggest that while Hoxb5b participates in vagal NCC development as a driver of progenitor expansion, the supernumerary, ectopically localized NCC fail to initiate expansion programs in timely fashion in the gut. All together, these data point to a model in which Hoxb5b regulates NCCs both in a tissue specific and temporally restricted manner.

scholarly journals Requirement of CRAMP for mouse macrophages to eliminate phagocytosed E. coli through an autophagy pathway

2021 ◽  
pp. jcs.252148
Author(s):  
Keqiang Chen ◽  
Teizo Yoshimura ◽  
Wanghua Gong ◽  
Cuimeng Tian ◽  
Jiaqiang Huang ◽  
...  
Keyword(s):  
Antimicrobial Peptides ◽  
Bacterial Infections ◽  
Active Form ◽  
Intracellular Bacteria ◽  
Intracellular Pathogens ◽  
Wild Type ◽  
E Coli ◽  
Mouse Macrophages ◽  
Autophagy Pathway ◽  
Related Proteins

Host-derived antimicrobial peptides play an important role in the defense against extracellular bacterial infections. However, the capacity of antimicrobial peptides derived from macrophages as potential antibacterial effectors against intracellular pathogens remains unknown. In this study, we report that normal (wild type, WT) mouse macrophages increased their expression of the cathelin-related antimicrobial peptide (CRAMP) after infection by viable E. coli or stimulation with inactivated E. coli and its product LPS, a process involving activation of NF-κB followed by protease-dependent conversion of CRAMP from an inactive precursor to an active form. The active CRAMP was required by WT macrophages to eliminate phagocytosed E. coli, with participation of autophagy-related proteins ATG5, LC3-II, and LAMP-1 as well as conjugation of the bacteria with p62. This process was impaired in CRAMP−/- macrophages resulting in retention of intracellular bacteria and fragmentation of macrophages. These results indicate CRAMP as a critical component in autophagy-mediated clearance of intracellular E. coli by mouse macrophages.

scholarly journals Requirement of the antimicrobial peptide CRAMP for macrophages to eliminate phagocytosed E. coli through an autophagy pathway

2020 ◽  
Author(s):  
Keqiang Chen ◽  
Teizo Yoshimura ◽  
Wanghua Gong ◽  
Cuimeng Tian ◽  
Jiaqiang Huang ◽  
...  
Keyword(s):  
Antimicrobial Peptides ◽  
Antimicrobial Peptide ◽  
Bacterial Infections ◽  
Active Form ◽  
Intracellular Bacteria ◽  
Wild Type ◽  
E Coli ◽  
Mouse Macrophages ◽  
Autophagy Pathway ◽  
Related Proteins

AbstractHost-derived antimicrobial peptides play an important role in the defense against extracellular bacterial infections. However, the capacity of antimicrobial peptides derived from macrophages as potential antibacterial effectors against intracellular pathogens remains unknown. In this study, we report that normal (wild type, WT) mouse macrophages increased their expression of the cathelicidin-related antimicrobial peptide (CRAMP) after infection by viable E. coli or stimulation with inactivated E. coli and its product LPS, a process involving activation of NF-κB followed by protease-dependent conversion of CRAMP from an inactive precursor to an active form. The active CRAMP was required by WT macrophages to eliminate phagocytosed E. coli, with participation of autophagy-related proteins ATG5, LC3-II, and LAMP-1 as well as conjugation of the bacteria with p62. The autophagy-mediated elimination of E. coli was impaired in CRAMP−/− macrophages resulting in retention of intracellular bacteria and fragmentation of macrophages. These results indicate CRAMP as a critical component in autophagy-mediated clearance of intracellular E. coli by macrophages.

scholarly journals Tissue Localization of the Endosymbiotic Bacterium “Candidatus Blochmannia floridanus” in Adults and Larvae of the Carpenter Ant Camponotus floridanus

2002 ◽  
Vol 68 (9) ◽  
pp. 4187-4193 ◽  
Author(s):  
Christina Sauer ◽  
Dieter Dudaczek ◽  
Bert Hölldobler ◽  
Roy Gross
Keyword(s):  
Developmental Stages ◽  
Light And Electron Microscopy ◽  
Cultivation Conditions ◽  
Camponotus Floridanus ◽  
Endosymbiotic Bacteria ◽  
Carpenter Ant ◽  
Negative Effect ◽  
Virgin Queens ◽  
Number Of Bacteria

ABSTRACT The distribution of endosymbiotic bacteria in different tissues of queens, males, and workers of the carpenter ant Camponotus floridanus was investigated by light and electron microscopy and by in situ hybridization. A large number of bacteria could be detected in bacteriocytes within the midguts of workers, young virgin queens, and males. Large amounts of bacteria were also found in the oocytes of workers and queens. In contrast, bacteria were not present in oocyte-associated cells or in the spermathecae of mature queens, although occasionally a small number of bacteria could be detected in the testis follicles of males. Interestingly, the number of bacteriocytes in mature queens was strongly reduced and the bacteriocytes contained only very few or no bacteria at all, although the endosymbionts were present in huge amounts in the ovaries of the same animals. During embryogenesis of the deposited egg, the bacteria were concentrated in a ring of endodermal tissue destined to become the midgut in later developmental stages. However, during larval development, bacteria could also be detected in other tissues although to a lesser extent. Only in the last-instar larvae were bacteria found exclusively in the midgut tissue within typical bacteriocytes. Tetracycline and rifampin efficiently cleansed C. floridanus workers of their symbionts and the bacteriocytes of these animals still remained empty several months after treatment had ceased. Despite the lack of their endosymbionts, these adult animals were able to survive without any obvious negative effect under normal cultivation conditions.

Ultrastructure of the midgut epithelium in three species of Macrobiotidae (Tardigrada: Eutardigrada: Parachela)

2019 ◽  
Author(s):  
M Rost-Roszkowska ◽  
K Janelt ◽  
I Poprawa
Keyword(s):  
Lipid Droplets ◽  
Digestive System ◽  
Midgut Epithelium ◽  
Middle Region ◽  
Reserve Material ◽  
Digestive Cells ◽  
Intracellular Digestion ◽  
Carnivorous Species ◽  
Males And Females ◽  
Anterior Ring

Abstract Three species of Macrobiotidae, Macrobiotus polonicus, Macrobiotus diversus and Macrobiotus pallarii, were selected for analysis of the fine structure of the midgut epithelium. They are gonochoric and carnivorous species that live in wet terrestrial and freshwater environments. The ultrastructure of the midgut epithelium of the investigated Macrobiotidae species was analysed in both males and females. Their digestive system is composed of fore- and hindguts that are covered by a cuticle, and the middle region, termed the midgut. It is lined with a simple epithelium that is formed by digestive cells that have a distinct brush border. Crescent-shaped cells that form an anterior ring in the border between the fore- and midgut were detected. The ultrastructure of the intestinal epithelium of the examined species differs slightly depending on sex. The digestive cells of the posterior segment of the intestine contain numerous lipid droplets, which are the reserve material. We concluded that the digestive cells of the Macrobiotidae midgut are responsible for its intracellular digestion owing to endocytosis. They also participate in the extracellular digestion owing to merocrine secretion (exocytosis). However, the midgut is not the main organ that accumulates reserve material. Additionally, the midgut epithelium does not participate in oogenesis.

scholarly journals Systematic identification of autophagy-related proteins in Aedes albopictus

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245694
Author(s):  
Yu Wang ◽  
Jialu Qiao ◽  
Dandan Zhang ◽  
Chunyan Zhong ◽  
Shengya Wang ◽  
...  
Keyword(s):  
Aedes Albopictus ◽  
Developmental Stages ◽  
Expression Profiles ◽  
Basic Information ◽  
Research Attention ◽  
Autophagy Pathway ◽  
Arbovirus Infection ◽  
Related Proteins ◽  
Systematic Identification

Autophagy is a conserved cellular process playing a role in maintenance of cellular homeostasis and response to changing nutrient conditions via degradation and recirculation of cellular redundant components. Autophagy-related proteins (Atg) play important function in autophagy pathway. Aedes albopictus mosquito is an effective vector transmitting multiple viruses which cause serious human diseases. Moreover, Aedes albopictus mosquito is becoming a serious threat to human health due to its widening distribution in recent years and thus worth of more research attention. It was reported that autophagy might play a role in viral infection in Aedes mosquito. To better understand the interaction between autophagy and arbovirus infection in mosquito system, it is necessary to identify autophagy pathway in the system. However, autophagy in Aedes albopictus mosquito is still poorly understood so far. We recently identified AaAtg8, the first Atg protein reported in Aedes albopictus mosquito. This work further identified twelve atg genes in Aedes albopictus mosquito. Sequence and phylogenetic analysis of the twelve atg genes were performed. Expression profiles of all the twelve Aaatg genes in different developmental stages and genders of Aedes albopictus mosquito were conducted. Effects of chemicals inhibiting or inducing autophagy on the levels of eight identified AaAtg proteins were examined. The function of two identified AaAtg proteins AaAtg6 and AaAtg16 and their response to arbovirus SINV infection were studied preliminarily. Taken together, this work systematically identified Aedes albopictus atg genes and provided basic information which might help to elucidate the autophagy pathway and the role of autophagy in arbovirus infection in Aedes mosquito system.

Correlated Studies of Cellular Interactions Using TEM, Freeze Etching, and SEM

1974 ◽  
Vol 32 ◽  
pp. 320-321
Author(s):  
J. P. Revel
Keyword(s):  
Developmental Stages ◽  
Three Dimensional ◽  
Cell Movement ◽  
Cellular Interactions ◽  
Serial Sections ◽  
Cell Sheets ◽  
Freeze Etching ◽  
Early Developmental

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.

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