ABSTRACT
Recent advances in molecular technology have revolutionized research on all aspects of the biology of organisms, including ciliates, and created unprecedented opportunities for pursuing a more integrative approach to investigations of biodiversity. However, this goal is complicated by large gaps and inconsistencies that still exist in the foundation of basic information about biodiversity of ciliates. The present paper reviews issues relating to the taxonomy of ciliates and presents specific recommendations for best practice in the observation and documentation of their biodiversity. This effort stems from a workshop that explored ways to implement six Grand Challenges proposed by the International Research Coordination Network for Biodiversity of Ciliates (IRCN-BC). As part of its commitment to strengthening the knowledge base that supports research on biodiversity of ciliates, the IRCN-BC proposes to populate The Ciliate Guide, an online database, with biodiversity-related data and metadata to create a resource that will facilitate accurate taxonomic identifications and promote sharing of data.
Subject(s)
Ciliophora/classification , Databases, Factual , Biodiversity , Ciliophora/genetics , Internet , PhylogenyABSTRACT
Two populations of Epistylis chlorelligerum Shen 1980, a colonial limnetic peritrich ciliate, were collected from different locations in China: E. chlorelligerum 1 from West Lake, Hangzhou; E. chlorelligerum 2 from East Lake, Wuhan. The morphology, infraciliature and SSU rRNA gene sequence of the two populations were investigated based on living and protargol-stained specimens. Although both populations are consistent with previous descriptions of protargol-stained specimens of this species, some differences in the morphology in vivo were observed. The two populations had identical SSU rRNA gene sequences. A second species, Epistylis chrysemydis Bishop and Jahn 1941, was also collected from East Lake, Wuhan, and was investigated for its morphology, infraciliature and SSU rRNA gene sequence. Phylogenetic analyses based on SSU rRNA gene sequence data indicate that the two populations of E. chlorelligerum are nested within the Epistylididae clade near E. wenrichi and E. urceolata. Epistylis chrysemydis is sister to the group comprising E. chlorelligerum, E. wenrichi, and E. urceolata.
Subject(s)
Oligohymenophorea/genetics , Phylogeny , China , DNA, Protozoan/genetics , DNA, Ribosomal/genetics , Genes, Protozoan , Genes, rRNA , Lakes , Oligohymenophorea/classification , Oligohymenophorea/cytology , Oligohymenophorea/isolation & purification , Sequence Analysis, DNAABSTRACT
The present study emphasizes the role of sulphide on ultrasonic cavitation erosion-corrosion (UCE-C) behaviors of HVOF-sprayed WC-Cr3C2-Ni coating in 3.5 wt% NaCl solution with different sulphide concentrations. The results indicated that the ultrasonic cavitation erosion (UCE) resistance of the coating decreased significantly with increasing sulphide concentration. The coating reacted with oxygen and anion those transferred by UCE, and the cavitation impact force led to the lack of support for tungsten carbide particles, which resulted in the reduction in the mass of the coating. There were two main factors those affected the UCE-C mechanism, in which the passivation film helped to reduce the mass loss of the coating, while the impact force caused by cavitation destroyed the passivation film, led to the accelerated anion diffusion and ultimately accelerated the mass loss of the coating. Mechanical erosion dominated the UCE-C of the coating in all tested solutions.
ABSTRACT
In this article, the WC-10Ni coatings were fabricated by HVOF spray, then the ultrasonic cavitation erosion performances of the coatings in distilled water and 3.5â¯wt% NaCl solution with various Na2S concentrations (0, 20 and 200â¯ppm) were investigated. The results of the cumulative volume loss of the coating in different mediums showed that the coating exhibited enhanced cavitation erosion resistance with the increase of Na2S concentrations in medium. The reason for the improvement on the cavitation erosion performance was the growth of corrosion product films containing sulphide. In comparison with the coating after cavitation erosion in medium without Na2S, no large craters and deep grooves were observed on the eroded coating surface in medium with Na2S. The ultrasonic cavitation damage of the coating manifests as the spall of the metal binder phase (Ni) and exposure of the hard phase (WC).
ABSTRACT
The stomatogenesis of peritrich ciliates is an important developmental process but has been studied relatively little for such a large, diverse taxon. Complex oral structures and an inability of staining techniques to reveal them clearly have been the major factors hindering investigation of this process. In the present study, an improved method of staining with protargol was used to investigate the entire process of stomatogenesis in a large, colonial species of peritrich, Pseudepistylis songi, and to compare it to descriptions of stomatogenesis in several other species. We found that P. songi and other peritrichs have the same general type of ophryobuccokinetal stomatogenesis, with the parental oral complex being inherited by one daughter and the new oral complex by the other daughter; however, some differences between individual taxa appear to have arisen in the course of evolution. Reorganization of the entire germinal kinety (Gk) to form the germinal anlage may be plesiomorphic, with restriction of reorganization to its abstomal part being apomorphic. Development of the entire new haplokinety of one daughter cell (2Hk) from the germinal band or its homologue also appears to be plesiomorphic, with development of peristomial and infundibular parts of 2Hk from separate rudiments being apomorphic. Furthermore, development of the new Gk of the parental oral complex (1Gk) from the entire infundibular part of the parental haplokinety (1Hk) may be plesiomorphic, and development from just the abstomal part may be apomorphic. Finally, development of the Gk of the new oral complex (2Gk) from residual kinetosomes of the germinal band appears to be plesiomorphic.
Subject(s)
Biological Evolution , Ciliophora/classification , Ciliophora/ultrastructure , Parasitology/methods , Microscopy/methods , Staining and Labeling/methodsABSTRACT
The study of human settlement environment, especially the complete study of human settlement environment in mountainous region, is a huge systematic project, which involves almost all aspects of human knowledge system at the semantic level. It is an important task to establish a systematic cognitive model of human settlement environment and carry out practical verification. In recent years, due to the rise of tourism real estate, mountain tourism real estate, as a type of tourism real estate, has attracted people's attention, and its hidden economic, social, and ecological benefits make it develop rapidly. The purpose of this study is to improve the theoretical system of tourism real estate landscape planning and mountain landscape resource protection system with 3D image technology, which has important theoretical and practical significance for exploring the sustainable development method of mountain tourism real estate landscape. This study locates the research type of mountain tourism real estate, and it is the first time to study mountain tourism, explores the specific planning of mountain tourism real estate development measures, and preliminary establish the theoretical system of mountain tourism real estate development. It brings a new idea for the development of mountain tourism real estate and puts forward the direction and method of planning.
Subject(s)
Ecology , Tourism , Humans , Technology , WaterABSTRACT
An oligohalobic peritrichous ciliate, Epistylis chlorelligerum Shen, 1980, was collected from a ditch in Hangzhou, China. The morphology, oral infraciliature, and morphogenesis of the species were studied using living and protargol-impregnated specimens. Zooids of E. chlorelligerum are 160-230 × 50-60 µm in vivo, and characterized by green-colored endoplasm containing symbiotic algae. The oral infraciliature presents a well-developed filamentous reticulum linked to the circular fiber of the cytostome; the outer two rows of P3 extend adstomally over P1 and usually enfold it. During binary fission, one daughter cell inherits most part of the old buccal apparatus and the reorganized haplokinety and germinal kinety (Hk' and G'), and new buccal apparatus of the other daughter cell is mostly developed from the original germinal kinety (G) and haplokinety (Hk): new peniculi 2, 3 (2P2, 2P3), new haplokinety (2Hk), and new germinal kinety (2G) are formed from G, while the new peniculus 1 (2P1) and its peristomial extention (2Pk) originate from Hk. The epistomial membrane can be observed until the two sets of buccal apparatus begin to separate from each other.
Subject(s)
Ciliophora/cytology , Ciliophora/growth & development , Fresh Water/parasitology , China , Ciliophora/classification , Ciliophora/isolation & purificationABSTRACT
Although silicon has highest specific capacity as anode for lithium-ion battery (LIB), its large volume change during the charge/discharge process becomes a great inevitable hindrance before commercialization. Metal silicides may be an alternative choice because they have the ability to accommodate the volume change by dispersing Si in the metal matrix as well as very good electrical conductivity. Herein we report on the suitability of lithium-ion uptake in C54 TiSi2 prepared by the "chemical oven" self-propagating high-temperature synthesis from the element reactants, which was known as an inactive metal silicide in lithium-ion storage previously. After being wrapped by graphene, the agglomeration of TiSi2 particles has been efficiently prevented, resulting in an enhanced lithium-ion storage performance when using as an anode for LIB. The as-received TiSi2/RGO hybrid exhibits considerable activities in the reversible lithiation and delithiation process, showing a high reversible capacity of 358 mAh/g at a current density of 50 mA/g. Specially, both TiSi2 and TiSi2/RGO electrodes show a remarkable enhanced electrochemical performance along with the cycle number, indicating the promising potential in lithium-ion storage of this silicide. Ex-situ XRD during charge/discharge process reveals alloying reaction may contribute to the capacity of TiSi2. This work suggests that TiSi2 and other inactive transition metal silicides are potential promising anode materials for Li-ion battery and capacitor.
ABSTRACT
With rapid response to environmental changes, phytoplankton communities have been used as a favorable bioindicator to evaluate environmental stress and anthropogenic impacts in aquatic ecosystems. The feasibility for their community-based bioassessment was studied in a mid-subtropical canal (Tiesha River), southern China, during a 1-year cycle (November 2009-December 2010). Samples were monthly collected at four sampling stations within a contamination gradient. Environmental variables, such as water temperature, dissolved oxygen (DO), chemical oxygen demand (COD), biological oxygen demand (BOD5), total phosphorus (TP), and total nitrogen (TN), were measured synchronously for comparison with biotic parameters. The phytoplankton community structures showed a significant difference among four stations. The spatial variation in abundance was significantly correlated with the changes in environmental variables, especially TN, TP, and COD. Four dominant species (Aulacoseira granulata, Leptocylindrus danicus, Oscillatoria tenuis, and Radiococcus nimbatus) were significantly correlated with nutrients, while the species richness index represented a significant correlation with BOD5. The phytoplankton-based Saprobien indices could not reveal the spatial variation in water quality status although may reflect water pollution levels (from ß- to α-mesosaprobic zone) in the canal system. It is suggested that phytoplankton communities might be used as a potentially robust bioindicator for discriminating environmental quality status in mid-tropical canal systems.
Subject(s)
Environmental Monitoring/methods , Phytoplankton/classification , Rivers/chemistry , Tropical Climate , Water Quality , Biota , China , Spatial AnalysisABSTRACT
The infraciliature and myoneme system of Campanella umbellaria were revealed using the protargol impregnation technique. The main characteristics of the infraciliature are the peristomial ciliary rows (haplokinety and polykineties), which make four and a half turns around the peristomial disc before plunging into the infundibulum, and the aboral infraciliature, which is made up of the aboral ciliary wreath (trochal band) and the scopula. The myoneme system is composed of: 1) longitudinal fibers, which include 60-84 (mean 72.3) short longitudinal fibers, 40-56 (mean 45.8) medium-length longitudinal fibers, and numerous long longitudinal fibers; and 2) circular fibers, which include 8-12 (mean 9.3) peristomial ring fibers, linking fibers, support fibers, and peristomial disc fibers. The various fibers in C. umbellaria are interconnected to form a single myoneme system that may act as a cell skeleton as well as providing the mechanism by which the zooid contracts and relaxes.
Subject(s)
Cilia/ultrastructure , Oligohymenophorea/ultrastructure , Animals , Photomicrography , Silver Proteins/chemistryABSTRACT
Previously, a series of Simocephalus taxa (Cladocera: Daphniidae) from China were described. Most were proposed to be junior synonyms in the last revision of the genus. Using original material from China and data from GenBank, we investigate the biodiversity and phylogeny of Simocephalus using sequences of the cytochrome c oxidase subunit I (COI) and the nuclear 18S genes. In both cases, neighbor-joining, maximum likelihood and Bayesian inference analyses led to highly congruent tree topologies. The grouping of the deeper clades agrees with the inter-generic classification of Orlova-Bienkowskaja (2001). Only the populations of S. serrulatus from Eurasia and North America seem to be closely related, and there are no other shared species between the two continents. Our study unambiguously confirms the existence of many lineages from the subgenera of Simocephalus (Echinocaudus) and Simocephalus s.str. in China, but their morphology needs to be reexamined by taking a wider range of characters (e.g., of female thoracic limbs and adult males) into consideration.
Subject(s)
Arthropod Proteins/genetics , Cladocera/classification , Cladocera/genetics , Electron Transport Complex IV/genetics , Phylogeny , Animals , China , Databases, Nucleic Acid , Female , MaleABSTRACT
A colpodean ciliate was found in the faeces of experimental rabbits. It was initially cultivated in medium mixed with 2% (w/v) rabbit faeces. Subsequently, two chemically defined media, designated CA-1 and CA-2, were found to be suitable for axenical cultivation of the ciliate. The maximum abundance of the ciliate isolate in the CA media was 1-2 × 10(5) cells/ml. The ciliate isolate was further identified with silver impregnation and molecular analysis. Features of the left oral polykinetid, somatic dikinetids, and sliverline pattern were similar to those of Colpoda aspera as described by Foissner (1993). The 18S small subunit ribosomal RNA gene of the ciliate isolate shared 99% sequence identity with that of C. aspera, with 100% coverage, and formed a sister clade in the phylogenetic tree with the reference C. aspera isolate. In addition, the trophozoite of C. aspera could proliferate over a temperature range from 25-37°C. When resting cysts were cultivated in CA-1 medium at 30-35°C, 98.2% of the trophozoites were detached from the cyst wall after 7 h.
Subject(s)
Ciliophora/classification , Ciliophora/growth & development , Phylogeny , Rabbits/parasitology , Animals , Ciliophora/cytology , Ciliophora/genetics , Ciliophora/isolation & purification , Culture Media , Culture Techniques , Feces/parasitology , RNA, Ribosomal, 18S/genetics , Sequence Homology, Nucleic AcidABSTRACT
A limnetic peritrichous ciliate, Epistylis plicatilis Ehrenberg, 1831, was collected from a freshwater ditch beside Moshan Hill, Wuhan, China. Its morphology, infraciliature, and morphogenesis were investigated based on specimens examined in vivo, following staining with protargol and by scanning electron microscopy. The characteristics of the Wuhan population of E. plicatilis are as follows: 1) colonial, each colony typically comprising 30-50 individuals, with a dichotomously branched, noncontractile stalk; 2) fully expanded zooids measure 90-155 × 30-50 µm in vivo; 3) a series of 6 or 7 conspicuous folds appear in the posterior region of the zooid when it contracts; 4) single horseshoe-shaped macronucleus oriented transversely; 5) single contractile vacuole located in peristomial region on dorsal wall of infundibulum; 6) myoneme system comprises 20-24 longitudinal fibers, peristomial disk fibers as a wreath-like net and peristomial ring fibers; 7) narrowly spaced transverse striations on the surface of the body; 8) infundibular polykineties 1 and 2 are three-rowed, infundibular polykinety 3 is two-rowed; and 9) stomatogenesis is of the buccokinetal type; in the new oral apparatus, infundibular polykineties 2 and 3, the haplokinety, and the germinal kinety all originate from the germinal kinety of the parental oral apparatus whereas the polykinety and infundibular polykinety 1 originate from the parental haplokinety. An improved diagnosis of E. plicatilis is supplied.
Subject(s)
Oligohymenophorea/growth & development , Animals , Cell Nucleus/physiology , Cell Nucleus/ultrastructure , Cell Nucleus Division , China , Cilia/ultrastructure , Microscopy, Electron, Scanning , Morphogenesis , Oligohymenophorea/ultrastructureABSTRACT
INTRODUCTION: In order to evaluate water quality of a canal system, the spatial pattern of protozoan communities in response to physicochemical variables was studied in the Hangzhou section of the Grand Canal, northern China during a 1-year cycle (February 2008-January 2009). MATERIALS AND METHODS: Protozoan samples were monthly collected at six sampling stations with a spatial gradient of environmental status. Physicochemical parameters, e.g., water temperature, dissolved oxygen, chemical oxygen demand (COD), biological oxygen demand, total nitrogen (TN), and total phosphorus (TP), were measured synchronously for comparison with biotic parameters. RESULTS: The protozoan community structures represented significant differences among the six sampling stations. The spatial patterns of protozoan communities were significantly correlated with the changes of chemical variables, especially COD, either alone or in combination with TP and/or TN. Of 88 protozoan taxa recorded over the study period, ten species (e.g., Carchesium polypinum, Colpidium campylum, Prorodon teres, Vorticella putrina, Zoothamnium arbuscula, Euglena spp., and Phacus spp.) were significantly related to COD, either alone or in combination with TP and/or TN. CONCLUSION: These findings suggest that protozoa can be used as a robust bioindicator of water quality in freshwater river systems.
Subject(s)
Ciliophora/isolation & purification , Ecosystem , Euglenida/isolation & purification , Fresh Water/parasitology , Water Quality , Biological Oxygen Demand Analysis , Chemical Phenomena , China , Cilia/metabolism , Ciliophora/classification , Ciliophora/cytology , Ciliophora/genetics , Environmental Monitoring/methods , Euglenida/classification , Euglenida/cytology , Euglenida/genetics , Flagella/metabolism , Fresh Water/chemistry , Nitrogen/analysis , Oxygen/analysis , Oxygen/chemistry , Phosphorus/analysis , Phylogeny , Principal Component Analysis , Rivers/chemistry , Rivers/parasitology , Seasons , Solubility , TemperatureABSTRACT
The process of stomatogenesis in peritrich ciliates is still incompletely understood. Previous studies on the stomatogenesis of four species of peritrichs, Telotrochidium sp., Carchesium polypinum, Opercularia coarctata, and Astylozoon pyriforme conflict with one another in some cases and omit details of events in others. We described the entire process of stomatogenesis in the peritrich ciliate Campanella umbellaria (C. umbellaria) using an improved method of staining with protargol. Our results disagree with some previous studies with regard to the formation of some rudimentary structures, reorganization of the parental haplokinety, formation of new germinal rows, and separation of daughter oral complexes. The pattern of stomatogenesis characteristic of peritrichs is compared to the stomatogenetic patterns of three other oligohymenophorean subclasses and a hypothesis about the evolution of stomatogenesis in the class Oligohymenophorea is offered. Details of stomatogenesis need to be described and verified in a greater variety of peritrichs to clarify possible differences between taxa and make it possible to relate stomatogenesis to evolution within the subclass Peritrichia. Ultrastructural studies are the next step in description of morphogenetic processes in peritrichs, and characteristics of C. umbellaria make it a useful model for this work.