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Annual Review of Genetics Nov 2023The ciliate genus served as one of the first model systems in microbial eukaryotic genetics, contributing much to the early understanding of phenomena as diverse as... (Review)
Review
The ciliate genus served as one of the first model systems in microbial eukaryotic genetics, contributing much to the early understanding of phenomena as diverse as genome rearrangement, cryptic speciation, cytoplasmic inheritance, and endosymbiosis, as well as more recently to the evolution of mating types, introns, and roles of small RNAs in DNA processing. Substantial progress has recently been made in the area of comparative and population genomics. species combine some of the lowest known mutation rates with some of the largest known effective populations, along with likely very high recombination rates, thereby harboring a population-genetic environment that promotes an exceptionally efficient capacity for selection. As a consequence, the genomes are extraordinarily streamlined, with very small intergenic regions combined with small numbers of tiny introns. The subject of the bulk of research, the ancient species complex, is descended from two whole-genome duplication events that retain high degrees of synteny, thereby providing an exceptional platform for studying the fates of duplicate genes. Despite having a common ancestor dating to several hundred million years ago, the known descendant species are morphologically indistinguishable, raising significant questions about the common view that gene duplications lead to the origins of evolutionary novelties.
Topics: Paramecium; Evolution, Molecular; Genomics; Genome; Mutation Rate
PubMed: 38012024
DOI: 10.1146/annurev-genet-071819-104035 -
Communicative & Integrative Biology 2024I summarize my recent theorizing on orientation and navigation across life. Organisms use navigational servomechanisms working with oscillators to get to goals....
I summarize my recent theorizing on orientation and navigation across life. Organisms use navigational servomechanisms working with oscillators to get to goals. Navigational servomechanisms track errors from the best direction of travel and initiate action to correct the error. They work with endogenously generated action patterns, oscillations produced by oscillators, to adjust the course of travel. The theme applies to all scales of life from micrometers to thousands of kilometers. Servomechanisms and oscillators also characterize some other domains of cognition.
PubMed: 38173690
DOI: 10.1080/19420889.2023.2293268 -
Journal of Ayub Medical College,... 2023A group of eukaryotic organisms that are either free-living or parasitic and feed on organic matter, such as microorganisms or organic detritus. This group is referred...
BACKGROUND
A group of eukaryotic organisms that are either free-living or parasitic and feed on organic matter, such as microorganisms or organic detritus. This group is referred to as a polyphyletic classification. They can be found in a wide variety of patterns and sizes, ranging from an amoeba, which can vary its shape, to a paramecium, which has a fixed shape and a complicated structure. The objective was to find out the occurrence of Entamoeba gingivalis and Trichomonas among Dental Patients visiting the Periodontology Department Dental Section, Sandeman, Provincial Hospital Quetta.
METHODS
The study design was randomized cross-sectional and conducted in the Department of Periodontology Dental Section, Sandeman Provincial Hospital Quetta, from March 2022 to February 2023. A total of 110 known cases of periodontitis and gingivitis were recruited in this study, and further to laboratory work the bacterial biofilm samples were collected from both gingivitis and periodontitis patients. The dental plaque was placed on individual glass microscope slides and a drop of saline and mixed and covered with a coverslip. The wet smear was examined immediately under 40X, and the objective for the presence and absence of motile amoebae or flagellated protozoa was recorded. .
RESULTS
out of 110 known cases of periodontitis and gingivitis 91 (83%) patients were males and 19 (17%) were females among 110 patients, 40 (36%) patients were periodontitis and 70 (64%) patients were gingivitis. Among 40 (36%) periodontitis patients 3(7.5%) were Entamoeba gingivalis and 4(10%) were Trichomonas Tenax while 70 (64%) cases of Gingivitis 20 (28%) of Entamoeba gingivalis and 1(1%) Trichomonas tenax was recorded. No patient had both species of protozoa were seen in this study.
CONCLUSION
The results of this study revealed the frequency of occurrence of E. gingivalis and T. tenax and the state of periodontitis and gingivitis. The prevalence of E. gingivalis was higher than T. tenax. We recommended further research with a higher number of patients and may use more advanced and reliable laboratory techniques such as PCR and electron microscopy.
Topics: Male; Female; Humans; Trichomonas; Entamoeba; Cross-Sectional Studies; Gingivitis; Periodontitis
PubMed: 38406902
DOI: 10.55519/JAMC-S4-12660 -
European Journal of Protistology Aug 2023Two already known representatives of Holospora-like bacteria, "Candidatus Gortzia yakutica" from Paramecium putrinum and Preeria caryophila, originally retrieved from...
Two already known representatives of Holospora-like bacteria, "Candidatus Gortzia yakutica" from Paramecium putrinum and Preeria caryophila, originally retrieved from the Paramecium aurelia complex, were found in new hosts: Paramecium nephridiatum and Paramecium polycaryum, respectively. In the present study, these bacteria were investigated using morphological and molecular methods. For "Ca. G. yakutica", the first details of the electron microscopic structure in the main and new hosts were provided. Regarding Pr. caryophila, the ultrastructural description of this species was implemented by several features previously unknown, such as the so called "membrane cluster" dividing periplasm from cytoplasm and fine composition of infectious forms before and during its releasing from the infected macronucleus. The new combinations of these Holospora-like bacteria with ciliate hosts were discussed from biogeographical and ecological points of view. Host specificity of symbionts as a general paradigm was critically reviewed as well.
Topics: Holosporaceae; Symbiosis; Bacteria; Macronucleus; Paramecium; Phylogeny
PubMed: 37356197
DOI: 10.1016/j.ejop.2023.125998 -
Nature Communications Aug 2023Material-based tactics have attracted extensive attention in driving the functional evolution of organisms. In aiming to design steerable bioartificial organisms to...
Material-based tactics have attracted extensive attention in driving the functional evolution of organisms. In aiming to design steerable bioartificial organisms to scavenge pathogenic waterborne viruses, we engineer Paramecium caudatum (Para), single-celled microorganisms, with a semiartificial and specific virus-scavenging organelle (VSO). FeO magnetic nanoparticles modified with a virus-capture antibody (MNPs@Ab) are integrated into the vacuoles of Para during feeding to produce VSOs, which persist inside Para without impairing their swimming ability. Compared with natural Para, which has no capture specificity and shows inefficient inactivation, the VSO-engineered Para (E-Para) specifically gathers waterborne viruses and confines them inside the VSOs, where the captured viruses are completely deactivated because the peroxidase-like nano-FeO produces virus-killing hydroxyl radicals (•OH) within acidic environment of VSO. After treatment, magnetized E-Para is readily recycled and reused, avoiding further contamination. Materials-based artificial organelles convert natural Para into a living virus scavenger, facilitating waterborne virus clearance without extra energy consumption.
Topics: Viruses; Hydroxyl Radical; Peroxidase; Peroxidases; Antibodies, Viral
PubMed: 37537158
DOI: 10.1038/s41467-023-40397-5 -
International Journal of Food Science 2023The plant flavonoids taxifolin and rutin are among the best known and best studied antioxidants. In addition to their antioxidant properties, other pharmacobiological...
The plant flavonoids taxifolin and rutin are among the best known and best studied antioxidants. In addition to their antioxidant properties, other pharmacobiological properties have been established for these substances. At the same time, taxifolin and rutin are chemically labile. They are prone to oxidative degradation and have poor water solubility. Under conditions of their real consumption, all this can lead to a significant reduction or complete loss of bioactivity of these flavonoids. Flavonoid modification and encapsulation techniques can be used to overcome these barrier factors. The use of micronization process for taxifolin and rutin allows changing the lipophilicity values of antioxidants. For micronized taxifolin, the log value is 1.3 (1.12 for the control forms), and for rutin, it was 0.15 (-0.64 for the control forms). The antioxidant activity of micronized flavonoids has increased about 1.16 times compared to control forms. The present study evaluates the possibility of using encapsulation of premyconized flavonoids by complex coacervation, in order to preserve their antioxidant properties. The results of an in vitro digestion study show that the encapsulated forms of antioxidants retain their bioactivity and bioavailability better than their original forms. The bioavailability indices for the encapsulated forms of flavonoids are more than 1.6 times higher than for their original forms. The digested fractions of the encapsulated properties reveal better antioxidant properties than their original forms in in vitro tests evaluating the antioxidant properties on cultures of the protozoan and human neuroblastoma SH-SY5Y cells. Encapsulated rutin indicates the highest activity, 0.64 relative to PMA. Thus, the studies represent the feasibility of using encapsulation to protect flavonoids during digestion and ensure the preservation of their antioxidant properties.
PubMed: 37745180
DOI: 10.1155/2023/9456931 -
Ecology and Evolution Sep 2023Temperature change affects biological systems in multifaceted ways, including the alteration of species interaction strengths, with implications for the stability of...
Temperature change affects biological systems in multifaceted ways, including the alteration of species interaction strengths, with implications for the stability of populations and communities. Temperature-dependent changes to antipredatory responses are an emerging mechanism of destabilization and thus there is a need to understand how prey species respond to predation pressures in the face of changing temperatures. Here, using ciliate protozoans, we assess whether temperature can alter the strength of phenotypic antipredator responses in a prey species and whether this relationship depends on the predator's hunting behavior. We exposed populations of the ciliate to either (i) a sit-and-wait generalist predator () or (ii) a specialized active swimmer predator () across two different temperature regimes (15 and 25°C) to quantify the temperature dependence of antipredator responses over a 24-h period. We utilized a novel high-throughput automated robotic monitoring system to track changes in the behavior (swimming speed) and morphology (cell size) of at frequencies and resolutions previously unachievable by manual sampling. The change in swimming speed through the 24 h differed between the two temperatures but was not altered by the presence of the predators. In contrast, showed a substantial temperature-dependent morphological response to the presence of (but not ), changing cell shape toward a more elongated morph at 15°C (but not at 25°C). Our findings suggest that temperature can have strong effects on prey morphological responses to predator presence, but that this response is potentially dependent on the predator's feeding strategy. This suggests that greater consideration of synergistic antipredator behavioral and physiological responses is required in species and communities subject to environmental changes.
PubMed: 37664517
DOI: 10.1002/ece3.10474 -
Current Biology : CB Aug 2023Controlling intracellular osmolarity is essential to all cellular life. Cells that live in hypo-osmotic environments, such as freshwater, must constantly battle water...
Controlling intracellular osmolarity is essential to all cellular life. Cells that live in hypo-osmotic environments, such as freshwater, must constantly battle water influx to avoid swelling until they burst. Many eukaryotic cells use contractile vacuoles to collect excess water from the cytosol and pump it out of the cell. Although contractile vacuoles are essential to many species, including important pathogens, the mechanisms that control their dynamics remain unclear. To identify the basic principles governing contractile vacuole function, we investigate here the molecular mechanisms of two species with distinct vacuolar morphologies from different eukaryotic lineages: the discoban Naegleria gruberi and the amoebozoan slime mold Dictyostelium discoideum. Using quantitative cell biology, we find that although these species respond differently to osmotic challenges, they both use vacuolar-type proton pumps for filling contractile vacuoles and actin for osmoregulation, but not to power water expulsion. We also use analytical modeling to show that cytoplasmic pressure is sufficient to drive water out of contractile vacuoles in these species, similar to findings from the alveolate Paramecium multimicronucleatum. These analyses show that cytoplasmic pressure is sufficient to drive contractile vacuole emptying for a wide range of cellular pressures and vacuolar geometries. Because vacuolar-type proton-pump-dependent contractile vacuole filling and pressure-dependent emptying have now been validated in three eukaryotic lineages that diverged well over a billion years ago, we propose that this represents an ancient eukaryotic mechanism of osmoregulation.
Topics: Cytosol; Dictyostelium; Osmolar Concentration; Water-Electrolyte Balance; Vacuoles; Eukaryota; Water
PubMed: 37478864
DOI: 10.1016/j.cub.2023.06.061 -
Cell Reports Apr 2024In the ciliate Paramecium, precise excision of numerous internal eliminated sequences (IESs) from the somatic genome is essential at each sexual cycle. DNA...
In the ciliate Paramecium, precise excision of numerous internal eliminated sequences (IESs) from the somatic genome is essential at each sexual cycle. DNA double-strands breaks (DSBs) introduced by the PiggyMac endonuclease are repaired in a highly concerted manner by the non-homologous end joining (NHEJ) pathway, illustrated by complete inhibition of DNA cleavage when Ku70/80 proteins are missing. We show that expression of a DNA-binding-deficient Ku70 mutant (Ku70-6E) permits DNA cleavage but leads to the accumulation of unrepaired DSBs. We uncoupled DNA cleavage and repair by co-expressing wild-type and mutant Ku70. High-throughput sequencing of the developing macronucleus genome in these conditions identifies the presence of extremities healed by de novo telomere addition and numerous translocations between IES-flanking sequences. Coupling the two steps of IES excision ensures that both extremities are held together throughout the process, suggesting that DSB repair proteins are essential for assembly of a synaptic precleavage complex.
Topics: Paramecium; DNA Cleavage; DNA Breaks, Double-Stranded; Genome, Protozoan; Ku Autoantigen; DNA Repair; Protozoan Proteins; DNA End-Joining Repair
PubMed: 38547127
DOI: 10.1016/j.celrep.2024.114001 -
Biophysics and Physicobiology Jun 2023In , a mechanical stimulus applied to the posterior portion of the cell causes a transient increase in membrane permeability to potassium ions, transiently rendering the...
In , a mechanical stimulus applied to the posterior portion of the cell causes a transient increase in membrane permeability to potassium ions, transiently rendering the membrane in a hyperpolarized state. Hyperpolarization causes a transient increase in Cyclic adenosine monophosphate (cAMP) concentration in the cilia, resulting in a transient fast-forward swimming of the cell. Schultz and coworkers (1992) reported that a unique adenylate cyclase (AC)-coupled potassium channel is involved in the reaction underlying this response, which is known as the "escape response." However, the AC responsible for this reaction remains to be identified. Moreover, the molecular linkage between mechanoreception and AC activation has not been elucidated adequately. Currently, we can perform an efficient and simple gene-knockdown technique in using RNA interference (RNAi). is one of the several model organisms for which whole-genome sequences have been elucidated. The RNAi technique can be applied to whole genome sequences derived from the database (ParameciumDB) to investigate the types of proteins that elicit specific biological responses and compare them with those of other model organisms. In this review, we describe the applications of the RNAi technique in elucidating the molecular mechanism underlying the escape response and identifying the AC involved in this reaction. The findings of this study highlight the advantages of the RNAi technique and ParameciumDB.
PubMed: 37867561
DOI: 10.2142/biophysico.bppb-v20.0025