Consequently, an abundant oxygen supply may allow P. By comparing P. To investigate the phylogenetic relationships among these globin genes, 45 globin sequences were retrieved from P. As shown in Supplementary Figure S3C , globin genes from one species exhibited a dispersed distribution instead of being clustered together, indicating that they may be amplified through speciation.
We then annotated the predicted protein-coding genes to the KEGG pathway. Compared with those of P. This finding indicates that P. However, the exact mechanism of how P. Previous studies revealed that the number of amino acid transporters in endosymbiotic algae increases significantly, and endosymbionts could obtain amino acids from P. According to the results of KO enrichment analysis, we speculated that nitrogen metabolism, especially glutamine and glutamate biosynthesis Fig.
To clarify the role of nitrogen metabolism in the endosymbiosis, we conducted differential expression analysis using the transcriptome data sets of P. Differential expressions of genes related to nitrogen metabolism amino acid metabolism, N-glycan metabolism and nucleotide metabolism were explored Fig.
Glutamine biosynthesis contributes to the establishment of endosymbiosis between P. Glutamine synthetase glnA can catalyze ammonia and glutamate to generate glutamine. The color depth represents the P value t -test. A L plasmid with the target gene was transferred into E. The phenotype of P. Control represents P. RNAi represents P. After RNAi, P. To further investigate the relationship between P.
We firstly cloned these target genes from the cDNA library of P. The expression vector L with the target gene sequence was induced by IPTG to produce dsRNA, which can knock down the expression of the target gene of the hosts. Subsequently, P. When E. After 6 days, we examined the phenotype of transformed P. As shown in Fig. Strikingly, the knockdown of Pb glnA could significantly reduce the number of symbiotic algae and the growth rate but did not affect the host cell size Fig. We counted the algal number per P.
These findings indicated that P. Based on the comparative genomic analyses, we propose a model of the symbiotic relationship between P.
In return, symbiotic algae may provide photosynthetic products, such as fructose, maltose, and oxygen, to host cells. Previous studies also proved our findings that there are nutrient trading systems between hosts and symbionts e.
O 2 , CO 2 , maltose and amino acids [ 37 ]. A schematic summary of the metabolic interaction between P. The blue arrow indicates that the MATE protein family excretes harmful metabolites.
The transcriptomes of P. Several studies also reported that the abundance of algal symbionts could be regulated by host according to light intensity [ 9 , 18 , 31 ]. In addition, the symbiotic algae are located under the cell cortex which may promote their photosynthetic efficiency. After removing algae from the host cells by using a cycloheximide treatment, the growth of algae-free P.
Interestingly, the oxygen-binding ability of P. For the host cells, the phototrophic symbionts can produce oxygen to keep their aerobic metabolism stable [ 38 ]. The globin gene family also undergoes extensive gene loss during adaptation to oxygen-enriched conditions.
Symbiotic algae may produce metabolites that are harmful to their hosts. The RNA interference experiment in this study confirmed the essential role of glutamine in maintaining the endosymbiotic relationship between P.
The algal number per host cell was reduced when the expression level of glnA in P. When the endosymbiotic system is established in P. Previous studies found that glnA mRNA levels and specific activities of glutamine synthetase could be regulated by nitrogen [ 39 ].
Through regulation of its glutamine production, P. This study provides a valuable model to examine the mechanism of endosymbiosis as well as a favorable candidate to study the origin of eukaryotic organelles. An anatomical lens was used to check the status and count numbers. Differential interference contrast microscope was employed to observe cellular morphological structure [ 6 , 8 ].
After 7—10 days, approximately 10 5 P. In addition, an algae-free P. The Paramecium strain and other related materials will be available upon request. To eliminate bacterial contamination and harvest more P. Each well with fragments was treated as a small library and sequenced using the HiSeq system.
The Canu software includes correction, trimming and assembling steps. Finally, we generated a near-complete Mauve software [ 41 ] was used to discover conserved synteny with rearrangements between P. The genome sequence of P. To identify protein-coding genes, de novo gene prediction, homolog-based and transcriptome-based methods were combined.
GeneMark-ES Suite 4. The protein sequences of four Paramecium species P. The trimmed reads were mapped to the P. All of the gene sets from the three approaches were merged to produce the eventual gene sets. The Pfam-A database was used to annotate protein domains by hmmscan using default parameters [ 49 ]. The gene name was derived from the best hit. A published RNA-sequencing data set of P. To identify orthologous genes among P.
Gblocks version 0. In totally, 69 orthologous genes with 23, amino acid residues were used to conduct the phylogenetic analysis Supplementary Table S5. ProtTest 3 [ 53 ] was employed to select optimum evolutionary model.
RAxML [ 54 ] constructed the ML tree with the optimum model for tandem orthologous protein sequences bootstrap The topological structures of the ML and BI phylogenetic trees were compared. Total RNA of P. Oligo-dT primer was used to reduce bacterial contamination in the samples. Positive clones were selected for plasmid extraction. Subsequently, the L plasmid was transferred into HTcompetent cells and spread on a plate LB medium with tetracycline and ampicillin.
Positive clones were cultured and induced by 0. Each day we cultured new E. When the E. Two-step evolution of endosymbiosis between hydra and algae. Article Google Scholar. Symbiosis between hydra and chlorella: molecular phylogenetic analysis and experimental study provide insight into its origin and evolution. Mol Phylogenet Evol. Different endosymbiotic Interactions in two hydra species reflect the evolutionary history of endosymbiosis.
Genome Biol Evol. Lipid accumulation during the establishment of kleptoplasty in Elysia chlorotica. PLoS One. Transcriptomic evidence that longevity of acquired plastids in the photosynthetic slugs Elysia timida and Plakobranchus ocellatus does not entail lateral transfer of algal nuclear genes.
Mol Biol Evol. Fujishima M, Kodama Y. Endosymbionts in Paramecium. The micronucleus is a generative nucleus that contains the genetic information that is passed along to offspring during reproduction.
The micronucleus is located near the macronucleus. Macronucleus — The macronucleus is ellipsoidal in shape almost like a kidney. The function of the macronucleus controls the metabolism of the cell.
The macronucleus lacks a nuclear membrane. The buccal cavity contains four structures called the endoral kinety, dorsal peniculus, ventral peniculus, and the dorsal quadrulus. The cytostome transfers the paramecium prey into the food vacuole. Cytoplasm — The cytoplasm is a jelly like substance that contains the organelles of the paramecium. The cytoplasm suspends the vesicles, ribosomes, and food storage reserves. The cytoplasm also contains everything the organism would need to synthesize proteins.
Food vacuoles — Unlike the contractile vacuole, the food vacuoles do not contract. Food vacuoles accumulate food gathered by paramecium through the cytostome.
Then once the food vacuole becomes a certain size it will break off and will travel through the cell. The food will be digested so to speak by enzymes. The useful material will remain in the cytoplasm and the remaining material will be expelled from the cell through the cytoproct.
The cytoproct is located, as you might expect, along the rear of the cell. Trichocyst — It is suggested that trichocysts are used in the defense of the paramecium. The trichocyst has a spindle shaped body and at the wider end and looks similar to a golf tee turned upside down. Trichocysts are located at specialized cortical sites and there are typically about one thousand per cell.
When the paramecium is attacked these little filaments are fired at the attacker to try and thwart the attack. There are 15 different species of paramecium in Aurelia group and a number of other species outside of the Aurelia group. There are other species that have had the classification disputed for several reasons. Paramecium species can be divided into two main groups, primarily by body shape, but also genetically and biochemically.
A few of the common species that fall into this grouping are Paramecium Aurelia, Paramecium Caudatum, Paramecium Multimicronucleatum. This group also has a more rounded rear. Paramecium are found all over the world. For more than years paramecium have been discovered and observed in many different habitats throughout the world.
As long as there is some organic material or decaying matter in a body of freshwater you can bet there is probably paramecium floating around. Fresh water paramecium species can be found in the following places:. Although the majority of species are found in freshwater there is one species of paramecium that can live naturally in water that contains a higher salinity than freshwater.
Paramecium Calkinsi can live and reproduce in tidal brine pools near the sea. If you are interested in observing these amazing microorganisms, the microscope I used to capture my photographs and video of paramecium can be found here on Amazon. I have also mounted this DSLR camera to my microscope which has vastly improved the quality of the video and photographs compared the microscope camera that came with my microscope. Paramecium feed on much smaller organisms than themselves like bacteria, yeast, and algae.
The paramecium uses these receptors to track down the bacteria. Once the bacteria are near enough it uses the cilia to push these organisms, along with some water, into the vestibulum.
They then move along the buccal cavity until it reaches the mouth cytostome. From there the bacteria will be acidified and killed. This will make it easier for the bacteria to be digested by the lysosomal enzymes. From there they get accumulated into food vacuoles which eventually get released into the cytoplasm. After circulating through the cell body, they will be digested by the lysosomal enzymes.
Eventually the vacuoles will shrink when the nutrients all pass into the cytoplasm. After the unused nutrients reach the anal pore they are expelled to the outside environment. Some microorganisms that prey on paramecium are amoebas, didiniums, and water fleas. Although paramecium do use trichocysts to defend themselves, they are also able to quickly and effectively rotate degrees to find a means of escape.
They can use their cilia to propel themselves quickly away from danger. Paramecium are not known as graceful microorganisms. In fact, if you were to observe paramecium movement under a microscope you would see quick movements in short bursts.
Since the Paramecium cells take up particles of various sizes, we attempted to use the electrically stimulated cells of P bursaria as the vehicle for transportation of micro-particles in the capillary system. By using apo-symbiotic cells of P bursaria obtained after forced removal of symbiotic algae, the uptake of the particles could be maximized and visualized. Then, electrically controlled transportations of particle-filled apo-symbiotic P bursaria cells were manifested.
0コメント