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Scientific Reports May 2024The patterns of Formin B and of the Arp2/3 complex formed during mitosis were studied in a mutant of Dictyostelium discoideum that produces multinucleate cells, which...
The patterns of Formin B and of the Arp2/3 complex formed during mitosis were studied in a mutant of Dictyostelium discoideum that produces multinucleate cells, which divide by the ingression of unilateral cleavage furrows. During cytokinesis the cells of this mutant remain spread on a glass surface where they generate a planar pattern based on the sorting-out of actin-binding proteins. During anaphase, Formin B and Arp2/3 became localized to the regions of microtubule asters around the centrosomes; Formin B in particular in the form of round, quite uniformly covered areas. These areas have been shown to be depleted of myosin II and the actin-filament crosslinker cortexillin, and to be avoided by cleavage furrows on their path into the cell.
Topics: Microtubules; Dictyostelium; Mitosis; Microfilament Proteins; Actin-Related Protein 2-3 Complex; Protozoan Proteins; Protein Transport; Cytokinesis; Actins
PubMed: 38755233
DOI: 10.1038/s41598-024-61967-7 -
Nature Communications May 2024Greenbeard genetic elements encode rare perceptible signals, signal recognition ability, and altruism towards others that display the same signal. Putative greenbeards...
Greenbeard genetic elements encode rare perceptible signals, signal recognition ability, and altruism towards others that display the same signal. Putative greenbeards have been described in various organisms but direct evidence for all the properties in one system is scarce. The tgrB1-tgrC1 allorecognition system of Dictyostelium discoideum encodes two polymorphic membrane proteins which protect cells from chimerism-associated perils. During development, TgrC1 functions as a ligand-signal and TgrB1 as its receptor, but evidence for altruism has been indirect. Here, we show that mixing wild-type and activated tgrB1 cells increases wild-type spore production and relegates the mutants to the altruistic stalk, whereas mixing wild-type and tgrB1-null cells increases mutant spore production and wild-type stalk production. The tgrB1-null cells cheat only on partners that carry the same tgrC1-allotype. Therefore, TgrB1 activation confers altruism whereas TgrB1 inactivation causes allotype-specific cheating, supporting the greenbeard concept and providing insight into the relationship between allorecognition, altruism, and exploitation.
Topics: Altruism; Chemotaxis; Dictyostelium; Membrane Proteins; Mutation; Protozoan Proteins; Signal Transduction; Spores, Protozoan
PubMed: 38734736
DOI: 10.1038/s41467-024-48380-4 -
Turkiye Parazitolojii Dergisi Dec 2023The aim of this study was to determine the prevalence of opportunistic parasites and spp. in patients with gastric cancer (CA) and to determine the significance of...
OBJECTIVE
The aim of this study was to determine the prevalence of opportunistic parasites and spp. in patients with gastric cancer (CA) and to determine the significance of these parasite.
METHODS
The patient group and the control group were composed of 100 people each. The stool samples were examined under the microscope for intestinal parasites with the native-Lugol method. Then, samples were multiplied by formol-ethyl acetate method and stained with modified acid-fast method.
RESULTS
Intestinal parasite positivity was indicated in 14% of the gastric CA, and 2% of the healthy individuals (p=0.001). spp. (p=0.009) was identified in 11%, spp. was identified in 4%, was identified in 2%, and was identified in 1% of the patient group. There were significant differences between the intestinal parasite positivity (p=0.012), abundant spp. positivity (p=0.041) and all Blastocystis spp. positivity (p=0.037) in patient and control groups. Most of the patients who were positive for parasites had diarrhea.
CONCLUSION
Based findings, it was concluded that it would be beneficial to evaluate gastric CA patients, especially those with diarrhea, for intestinal parasites.
Topics: Humans; Control Groups; Cryptosporidiosis; Stomach Neoplasms; Cryptosporidium; Blastocystis Infections; Intestinal Diseases, Parasitic; Blastocystis; Diarrhea; Feces; Prevalence
PubMed: 38149442
DOI: 10.4274/tpd.galenos.2023.33042 -
BMC Microbiology Jul 2023Acanthamoeba castellanii is a free-living protist that feeds on diverse bacteria. A. castellanii has frequently been utilized in studies on microbial interactions....
BACKGROUND
Acanthamoeba castellanii is a free-living protist that feeds on diverse bacteria. A. castellanii has frequently been utilized in studies on microbial interactions. Grazing bacteria also exhibit diverse effects on the physiological characteristics of amoebae, such as their growth, encystation, and cytotoxicity. Since the composition of amoebae amino acids is closely related to cellular activities, it can indicate the overall responses of A. castellanii to various stimuli.
METHOD
A. castellanii was exposed to different culture conditions in low-nutrient medium with heat-killed DH5α to clarify their effects. A targeted metabolomic technique was utilized to evaluate the concentration of cellular amino acids. The amino acid composition and pathways were analyzed by two web-based tools: MetaboAnalyst and Pathview. Then, long-term exposure to A. castellanii was investigated through in silico and in vitro methods to elucidate the homeostasis of amino acids and the growth of A. castellanii.
RESULTS
Under short-term exposure, all kinds of amino acids were enriched in all exposed groups. In contrast to the presence of heat-killed bacteria, the medium exhibited obvious effects on the amino acid composition of A. castellanii. After long-term exposure, the amino acid composition was more similar to that of the control group. A. castellanii may achieve amino acid homeostasis through pathways related to alanine, aspartate, citrulline, and serine.
DISCUSSION
Under short-term exposure, compared to the presence of bacteria, the type of medium exerted a more powerful effect on the amino acid composition of the amoeba. Previous studies focused on the interaction of the amoeba and bacteria with effective secretion systems and effectors. This may have caused the effects of low-nutrient environments to be overlooked.
CONCLUSION
When A. castellanii was stimulated in the coculture system through various methods, such as the presence of bacteria and a low-nutrient environment, it accumulated intracellular amino acids within a short period. However, different stimulations correspond to different amino acid compositions. After long-term exposure, A. castellanii achieved an amino acid equilibrium by downregulating the biosynthesis of several amino acids.
Topics: Acanthamoeba castellanii; Escherichia coli; Coculture Techniques; Amino Acids; Acclimatization; Hot Temperature; Culture Media
PubMed: 37495951
DOI: 10.1186/s12866-023-02942-6 -
Optics Express Feb 2024Brilliant colors in nature arise from the interference of light with periodic nanostructures resulting in structural color. While such biological photonic structures...
Brilliant colors in nature arise from the interference of light with periodic nanostructures resulting in structural color. While such biological photonic structures have long attracted interest in insects and plants, they are little known in other groups of organisms. Unexpected in the kingdom of Amoebozoa, which assembles unicellular organisms, structural colors were observed in myxomycetes, an evolutionary group of amoebae forming macroscopic, fungal-like structures. Previous work related the sparkling appearance of Diachea leucopodia to thin film interference. Using optical and ultrastructural characterization, we here investigated the occurrence of structural color across 22 species representing two major evolutionary clades of myxomycetes including 14 genera. All investigated species showed thin film interference at the peridium, producing colors with hues distributed throughout the visible range that were altered by pigmentary absorption. A white reflective layer of densely packed calcium-rich shells is observed in a compound peridium in Metatrichia vesparium, whose formation and function are still unknown. These results raise interesting questions on the biological relevance of thin film structural colors in myxomycetes, suggesting they may be a by-product of their reproductive cycle.
Topics: Myxomycetes; Amoebozoa; Calcium; Nanostructures; Photons
PubMed: 38439270
DOI: 10.1364/OE.511875 -
European Journal of Medical Research Nov 2023Irritable bowel syndrome (IBS) is a prevalent gastrointestinal (GI) tract disorder. Although the main reason for IBS is not clear, the interaction between intestinal...
Irritable bowel syndrome (IBS) is a prevalent gastrointestinal (GI) tract disorder. Although the main reason for IBS is not clear, the interaction between intestinal microorganisms and the gut barrier seems to play an important role in pathogenesis of IBS. The current study aimed to investigate the effect of Blastocystis on the gut microbiota profile and the circulation levels of microRNA (mir)-16 of IBS patients compared to healthy subjects. Stool and blood samples were collected from 80 participants including 40 samples from each IBS and healthy group. Upon DNA extraction from stool samples, barcoding region and quantitative real-time PCR were analyzed to investigate Blastocystis and the microbiota profile, respectively. RNA was extracted from serum samples of included subjects and the expression of mir-16 was evaluated using stem-loop protocol and qreal-time PCR. Significant changes between IBS patients and healthy controls was observed in Firmicutes, Actinobacteria, Faecalibacterium, and Alistipes. In IBS patients, the relative abundance of Bifidobacteria was directly correlated with the presence of Blastocystis, while Alistipes was decreased with Blastocystis. Lactobacillus was significantly increased in Blastocystis carriers. In healthy subjects, the relative abundance of Bifidobacteria was decreased, but Alistipes was increased in Blastocystis carriers. The changes in the Firmicutes/Bacteroidetes ratio was not significant in different groups. The relative expression of mir-16 in Blastocystis-negative IBS patients and healthy carriers was significantly overexpressed compared to control group. The presence of Blastocystis, decreased the relative expression of mir-16 in IBS patients compared to Blastocystis-negative IBS patients. The present study revealed that Blastocystis has the ability to change the abundance of some phyla/genera of bacteria in IBS and healthy subjects. Moreover, Blastocystis seems to modulate the relative expression of microRNAs to control the gut atmosphere, apply its pathogenicity, and provide a favor niche for its colonization.
Topics: Humans; Irritable Bowel Syndrome; Blastocystis Infections; Circulating MicroRNA; Case-Control Studies; Blastocystis; Microbiota; MicroRNAs
PubMed: 37932792
DOI: 10.1186/s40001-023-01441-8 -
Molecular Biology of the Cell Dec 2023Although the oncogene has been extensively studied, new aspects concerning its role and regulation in normal biology and cancer continue to be discovered. Recently,...
CRISPR-mediated reversion of oncogenic KRAS mutation results in increased proliferation and reveals independent roles of Ras and mTORC2 in the migration of A549 lung cancer cells.
Although the oncogene has been extensively studied, new aspects concerning its role and regulation in normal biology and cancer continue to be discovered. Recently, others and we have shown that the mechanistic Target of Rapamycin Complex 2 (mTORC2) is a Ras effector in and mammalian cells. mTORC2 plays evolutionarily conserved roles in cell survival and migration and has been linked to tumorigenesis. Because is often mutated in lung cancer, we investigated whether a Ras-mTORC2 pathway contributes to enhancing the migration of lung cancer cells expressing oncogenic Ras. We used A549 cells and CRISPR/Cas9 to revert the cells' G12S mutation to wild-type and establish A549 revertant (REV) cell lines, which we then used to evaluate the Ras-mediated regulation of mTORC2 and cell migration. Interestingly, our results suggest that K-Ras and mTORC2 promote A549 cell migration but as part of different pathways and independently of Ras's mutational status. Moreover, further characterization of the A549 cells revealed that loss of mutant K-Ras expression for the wild-type protein leads to an increase in cell growth and proliferation, suggesting that the A549 cells have low mutant dependency and that recovering expression of wild-type K-Ras protein increases these cells tumorigenic potential.
Topics: Animals; Humans; Lung Neoplasms; Genes, ras; A549 Cells; Proto-Oncogene Proteins p21(ras); Mechanistic Target of Rapamycin Complex 2; Dictyostelium; Cell Proliferation; Mutation; Cell Line, Tumor; Mammals
PubMed: 37729017
DOI: 10.1091/mbc.E23-05-0152 -
PeerJ 2024The evolution of symbiotic interactions may be affected by unpredictable conditions. However, a link between prevalence of these conditions and symbiosis has not been...
The evolution of symbiotic interactions may be affected by unpredictable conditions. However, a link between prevalence of these conditions and symbiosis has not been widely demonstrated. We test for these associations using social amoebae and their bacterial endosymbionts. commonly hosts endosymbiotic bacteria from three taxa: and Chlamydiae. Three species of facultative endosymbionts are the best studied and give hosts the ability to carry prey bacteria through the dispersal stage to new environments. and Chlamydiae are obligate endosymbiont lineages with no measurable impact on host fitness. We tested whether the frequency of both single infections and coinfections of these symbionts were associated with the unpredictability of their soil environments by using symbiont presence-absence data from isolates from 21 locations across the eastern United States. We found that symbiosis across all infection types, symbiosis with and Chlamydiae obligate endosymbionts, and symbiosis involving coinfections were not associated with any of our measures. However, unpredictable precipitation was associated with symbiosis in two species of , suggesting a link between unpredictable conditions and symbiosis.
Topics: Symbiosis; Soil Microbiology; Dictyostelium; Burkholderiaceae; Soil; United States; Chlamydia
PubMed: 38784393
DOI: 10.7717/peerj.17445 -
BMC Genomics May 2024The folate cycle of one-carbon (C1) metabolism, which plays a central role in the biosynthesis of nucleotides and amino acids, demonstrates the significance of metabolic...
BACKGROUND
The folate cycle of one-carbon (C1) metabolism, which plays a central role in the biosynthesis of nucleotides and amino acids, demonstrates the significance of metabolic adaptation. We investigated the evolutionary history of the methylenetetrahydrofolate dehydrogenase (mTHF) gene family, one of the main drivers of the folate cycle, across life.
RESULTS
Through comparative genomic and phylogenetic analyses, we found that several lineages of Archaea lacked domains vital for folate cycle function such as the mTHF catalytic and NAD(P)-binding domains of FolD. Within eukaryotes, the mTHF gene family diversified rapidly. For example, several duplications have been observed in lineages including the Amoebozoa, Opisthokonta, and Viridiplantae. In a common ancestor of Opisthokonta, FolD and FTHFS underwent fusion giving rise to the gene MTHFD1, possessing the domains of both genes.
CONCLUSIONS
Our evolutionary reconstruction of the mTHF gene family associated with a primary metabolic pathway reveals dynamic evolution, including gene birth-and-death, gene fusion, and potential horizontal gene transfer events and/or amino acid convergence.
Topics: Evolution, Molecular; Phylogeny; Methylenetetrahydrofolate Dehydrogenase (NADP); Multigene Family; Archaea; Eukaryota; Metabolic Networks and Pathways; Gene Transfer, Horizontal
PubMed: 38693486
DOI: 10.1186/s12864-024-10159-8 -
Infection and Immunity Aug 2023Previously, we showed that Legionella pneumophila secretes rhizoferrin, a polycarboxylate siderophore that promotes bacterial growth in iron-deplete media and the murine...
Previously, we showed that Legionella pneumophila secretes rhizoferrin, a polycarboxylate siderophore that promotes bacterial growth in iron-deplete media and the murine lung. Yet, past studies failed to identify a role for the rhizoferrin biosynthetic gene () in L. pneumophila infection of host cells, suggesting the siderophore's importance was solely linked to extracellular survival. To test the possibility that rhizoferrin's relevance to intracellular infection was missed due to functional redundancy with the ferrous iron transport (FeoB) pathway, we characterized a new mutant lacking both and . This mutant was highly impaired for growth on bacteriological media that were only modestly depleted of iron, confirming that rhizoferrin-mediated ferric iron uptake and FeoB-mediated ferrous iron uptake are critical for iron acquisition. The mutant, but not its -containing complement, was also highly defective for biofilm formation on plastic surfaces, demonstrating a new role for the L. pneumophila siderophore in extracellular survival. Finally, the mutant, but not its complement containing , proved to be greatly impaired for growth in Acanthamoeba castellanii, , and human U937 cell macrophages, revealing that rhizoferrin does promote intracellular infection by L. pneumophila. Moreover, the application of purified rhizoferrin triggered cytokine production from the U937 cells. Rhizoferrin-associated genes were fully conserved across the many sequenced strains of L. pneumophila examined but were variably present among strains from the other species of . Outside of , the closest match to the L. pneumophila rhizoferrin genes was in Aquicella siphonis, another facultative intracellular parasite of amoebae.
Topics: Animals; Mice; Humans; Legionella pneumophila; Siderophores; Amoeba; U937 Cells; Bacterial Proteins; Iron; Macrophages; Biofilms
PubMed: 37428036
DOI: 10.1128/iai.00072-23