Comparison of ciliature microtubule organelles in three hypotrichous ciliate species

We examined the structure and spatial organization of ciliature base-associated microtubules (BAM) in three hypotrichous ciliates (Stylonychia mytilus, Pseudourostyla cristata, Euplotes woodruffi) in fluorescence microscopy. The results revealed that BAM, including the anterior (ALM), posterior longitudinal microtubule (PLM) and the transverse microtubule (TM) bands, are composed of tubulin. The respective microtubular bands have cytoplasmic polarization patterns that are significantly asymmetric. The BAM of the midventral files in P. cristata appear cord-shaped compared with the ALM bands of transverse cirri in both S. mytilus and E. woodruffi, which extend to the left anterior side of the cell before converging. The TM bands of the left marginal cirri (MC) in S. mytilus extend to the right side of the cell, while those of the right MC bands extend to the left. Our observations suggest that BAM traits are common in hypotrichous ciliates even though different species possess different microtubule arrangements related to the conserved cirral morphogenetic patterns in the respective species. The differing development of BAM in the three ciliate suggests that the microtubules may be conserved in different hypotrichs. We have also demonstrated that the BAM, which appear polar and asymmetric, are localized in specific cytoskeletal positions and extend in different orientations within the cortex to connect with other ciliature-associated structures and, thus, strengthen the cortex. These BAM features indicate that they are directly associated with cell motion.     

Ultrastructure of extrusomes in hypotrichous ciliate Pseudourostyla nova

The ultrastructure of extrusomes of the hypotrichous ciliate Pseudourostyla nova was observed in scanning and transmission electron microscopy and enzyme-cytochemistry. The results show that the distribution, morphological characteristics, morphogenesis process, and extrusive process of the extrusomes in P. nova are different from the trichocysts in Paramecium, suggesting that the extrusomes of P. nova can respond to environmental stimuli, play an important role in the defense of this species, and cannot be regarded as "trichocysts". The results also suggest that the extrusomes might be originated from the Golgi apparatus and mature in the cytoplasm; after the extrusion of mature extrusomes, the residual substance might be reabsorbed and reused by the ciliate cell via food vacuoles, and take part in material recycling of the cell.     

Tissue culture of three species of Laurencia complex

To establish a micropropagation system of three Laurencia complex species (Laurencia okamurai, Laurencia tristicha, and Chondrophycus undulatus) by tissue culture techniques, we studied the regeneration characteristics and optimal culture conditions of axenic algal fragments cultured on solid medium and in liquid medium. Regeneration structures were observed and counted regularly under a reverse microscope to investigate the regeneration process, polarity and optimal illumination, and temperature and salinity levels. The results show that in most cultures of the three species, we obtained bud regeneration on solidified medium with 0.5% agar and in liquid medium. Rhizoid-like regeneration was filamentous and developed from the lower cut surface of fragments in L. okamurai, but was discoid and developed from the apical back side of bud regeneration in L. tristicha and C. undulatus. Regeneration polarity was localized to the apical part of algal fronds in all three species, and on fragments cut from the basal part of algae buds could develop from both the upper and the lower cut surfaces. Buds could develop from both the medullary and the cortical portions in L. okamurai and C. undulatus, while in L. tristicha, buds only emerged from the cortex. The optimal culture conditions for L. okamurai were 4 500 lx, 20°C and 35 (salinity); for C. undulatus, 4 500 lx, 20°C and 30; and for L. tristicha, 4 500 lx, 25°C and 30.     

Tissue culture of three species of Laurencia complex

To establish a micropropagation system of three Laurencia complex species (Laurencia okamurai, Laurencia tristicha, and Chondrophycus undulatus) by tissue culture techniques, we studied the regeneration characteristics and optimal culture conditions of axenic algal fragments cultured on solid medium and in liquid medium. Regeneration structures were observed and counted regularly under a reverse microscope to investigate the regeneration process, polarity and optimal illumination, and temperature and salinity levels. The results show that in most cultures of the three species, we obtained bud regeneration on solidified medium with 0.5% agar and in liquid medium. Rhizoid-like regeneration was filamentous and developed from the lower cut surface of fragments in L. okamurai, but was discoid and developed from the apical back side of bud regeneration in L. tristicha and C. undulatus. Regeneration polarity was localized to the apical part of algal fronds in all three species, and on fragments cut from the basal part of algae buds could develop from both the upper and the lower cut surfaces. Buds could develop from both the medullary and the cortical portions in L. okamurai and C. undulatus, while in L. tristicha, buds only emerged from the cortex. The optimal culture conditions for L. okamurai were 4 500 lx, 20°C and 35 (salinity); for C. undulatus, 4 500 lx, 20°C and 30; and for L. tristicha, 4 500 lx, 25°C and 30.     

我国9种养殖对虾形态特征之比较

本文对我国养殖的 9种对虾主要形态特征作了简要的描述 ,并根据它们的不同特征把这 9种对虾分成 4个组 :即中国对虾组、斑节对虾组、日本对虾组和凡纳对虾组。对各组间和组内不同种类对虾的形态特征作了比较 ,并根据它们不同的形态特征编出检索表 ,以便于生产上应用。     

ON THE MARINE CILIATE, Pseudocohnilembus hargisi （PROTOZOA, CILIOPHORA, SCUTICOCILIATIDA） WITH COMPARISON OF ITS RELATED SPECIES

The living morphology, nuclear apparatus, infraciliature and silverline system of the poorly-known ciliatePseudocohnilembus hargisi Evans & Thompson, 1964, collected from a shrimp culture pond in Qingdao, China, were examined by observation of the live specimen; and by the pyridinated carbonate method and Chatton-Lwoff technique. The main characteristics: 13–14 (usually 13) longitudinal or slightly spirally arranged somatic kineties; single contractile vacuole with usually 2 (1–2) pores at posterior ends of the fourth and fifth somatic kineties to the right of the buccal cavity. Several related congeners were compared and morphometrically tabulated. Project No. 39970098 supported by NSFC.     

Sequence Comparison of Partial Cytochrome b Genes of Two Coilia species

1Introduction Japanese grenadier anchovy,Coilia ectenes Jordanet Seale(1905),is distributed in the northwest Pacif-ic.The congener,Osbeck's grenadier anchovy,Coil-ia mystus(Linnaeus,1758),is widely distributed inthe west Pacific.Both species inhabit coastal watersand estuaries and can reach up to rivers.The twospecies are important contributors to the coastal fish-eries of China(Zheng et al.,2003).Many studies on the fishery biology of the twospecies have been conducted(Zheng et al.,2003)…     

Marine ciliate community in relation to eutrophication of coastal waters in the Yellow Sea

We assessed the potential of marine ciliate community as an indicator to coastal water quality using water samples collected from four stations in the Yellow Sea in the summer 2000. The four stations were characterized by different levels of pollution. The ciliate communities consisted primarily of tintinnids and aloricate ciliates that were <30 μm. A total of 78 species were classified: 55 species at Station 2, 51 species each at Stations 1 and 4, and 47 species at Station 3. The mean number of species at each site was 29.2±2.0 (Station 1), 28.5±2.9 (Station 2), 27.8±1.7 (Station 3), and 24.5±2.3 (Station 4). The abundance was highly variable: 19 331±11 187 ind./L at Station 1, 7 960±5 639 ind./L at Station 2, 29 015±12 999 ind./L at Station 3, and 8 190±4 658 ind./L at Station 4. Our results suggest that neither the simple chemical analysis (e.g. chemical oxygen demand, dissolved inorganic nitrogen, and phosphate) nor the eutrophication/pollution index adequately described the water quality at the four stations. The same was true of the number of species and their abundance, both of which had no correlation with the chemical indices. In contrast, Margalef’s diversity index values (3.12 at Station 2, 2.89 at Station 1, and 2.64 at Stations 3 and 4) generally discriminated the water quality status of the four stations. The difference in water quality among the stations was strongly supported by the pattern of species richness (i.e. the total number of species) of ciliates at each station. Our evaluation was consistent with the results of long-term water quality monitoring at the four stations. With increasing eutrophication, we observed also a compositional and functional shift in the ciliate assemblages from algivorous oligotrich/choreotrich to nonselective-omnivorous gymnostomatids to bacterivorous-detrivorous scuticociliatids. Thus, ciliates may be used to indicate the coastal water quality status of a given site.     

Comparative Analysis of Mitochondrial Control Region Sequence from Three Flatfish Species （Pleuronectidae）

The 5‘-end of the mitochondrial control region sequences of three flatfishes (Pleuronectiformes: Pleuronectidae) were amplified and sequenced. These sequences were compared with those of other three Pleuronectids species retrieved from GenBank. A phylogenetic tree was constructed based on the partial control region sequences. The results of phylogenetic analysis are consistent with those of conventional systematics. Compared to previous studies, the structure of the 5‘-end of mitochondrial control region was analyzed. The terminal associated sequence motif and its complementary motif were identified at the 5‘-end of the sequences. A conserved sequence block, named as CM5‘ d, was identified in the 5‘-end of control region sequences in all Pleuronectids. Another central conserved sequence block, named as CSB-F, was detected in the central conserved blocks.     

SHORT TIME DYNAMICS OF CILIATE ABUNDANCE IN THE BOHAI SEA （CHINA）

The ciliate community in the Bohai Sea (China) was studied from 23 September to 7 October 1998. A hurricane struck the study area between the two grid station investigations, which were six days apart. Six tintinnid species ( Favella panamensis, Leptotintinnus nordqvisti, Tintinnopsis but-schlii, T. karajacensis , T. Radix and Wangiella dicollaria ) were identified. Total cililate abundance in the surface layer ranged from 20 to 770 ind/l. In the first grid investigation, Tintinnopsis karajacensis dominated in the warm, low salinity waters at the Huanghe River mouth. Aloricate ciliate sp. 1 dominated in the cold, high salinity waters in the northwest of the study area and the Bohai Strait. In the second grid investigation, T. Karajacensis almost disappeared. The abundance of aloricate ciliate sp. 1 decreased drastically. The aloricate ciliate sp. 2 dominated at the Bohai Strait. The change of ciliate abundance may be due to the disturbance of hurricane.     

MORPHOLOGICAL COMPARISON OF THE FEEDING APPARATUS OF THREE CO-OCCURRING SPECIES OF PONYFISHES (LEIOGNATHIDAE)

ImOUocrON0verevoluti0narytirne,intetspeCiliccomPctitioncanresultincharactedisplacementSthatfadiitateresourcepartitioningamongspedesffeper,l985,Wilirarnanayake,l99O).Fisharenotablyopportunisticintheirfeding,toknowWhereandhowtheybowilloftenprovidemoreinsightintotheirerelogythansbolyknowingtheactUalcomPonentSoftheirdiet(Motta,l988,HUmPhrieS,l993).ArmrdinglymorphologicalcomParisonsamongcoxiccutwspchprovidemportantinfonnationnotonlytosySteInatistsfaedwithtaxonondcprobbo,butaIsot0erelogistS…     

Tests to evaluate the ecological impact of treated ballast water on three Chinese marine species

Ballast water has been a topic of concern for some time because of its potential to introduce invasive species to new habitats. To comply with the International Convention for the Control and Management of Ships＇ Ballast Water and Sediments, members of the International Maritime Organization （IMO） must equip their ships with on-board treatment systems to eliminate organism release with ballast water. There are many challenges associated with the implementation of this IMO guideline, one of which is the selection of species for testing the ecological impacts of the treated ballast water. In the United States, ballast water toxicity test methods have been defined by the United States Environmental Protection Agency. However, the test methods had not been finalized in China until the toxicity test methods for ballast water were established in 2008. The Chinese methods have been based on species from three trophic levels： Skeletonema costatum, Neomysis awatschensis, and Ctenogobius gymnauchen. All three species live in broad estuarine and open sea areas of China; they are sensitive to reference toxicants and acclimatize easily to different conditions. In this paper, the biological characteristics, test processes and statistical analysis methods are presented for the three species. Results indicate that the methods for evaluating these three organisms can be included in the ecological toxicity tests for treated ballast water in China.     

Descriptions of three new species of Mitridae （Mollusca： Gastropoda） from South China Sea

Three new species of Family Mitridae （Mollusca： Gastropoda） from the South China Sea are described in the present paper. They are Ziba aglais sp. nov. B. LI ＆ S. ZHANG, Neocancilla daidaleosa sp.nov. B. LI ＆ X. LI, and Mitra holkosa sp. nov. B. LI. Their systematic positions are also discussed.     

Comparative study of brine shrimp bioassay-based toxic activities of three harmful microalgal species that frequently blooming in aquaculture ponds

Journal of Oceanology and Limnology - Typical harmful micro-algal species constantly occurred in high density in marine aquaculture ponds in Xiangshan and Sanmen Bay, Zhejiang Province. Fates of...     

Comparison of stem taper models for the four tropical tree species in Mount Makiling,Philippines

This study was conducted to evaluate the performance of six stem taper models on four tropical tree species, namely Celtis luzonica (Magabuyo), Diplodiscus paniculatus (Balobo), Parashorea malaanonan (Bagtikan), and Swietenia macrophylla (Mahogany) in Mount Makiling Forest Reserve (MMFR), Philippines using fit statistics and lack-of-fit statistics. Four statistical criteria were used in this study, including the standard error of estimate (SEE), coefficient of determination (R ²), mean bias \(( \bar E )\), and absolute mean difference (AMD). For the lack-offit statistics, SEE, \(\bar E\) and AMD were determined in different relative height classes. The results indicated that the Kozako2 stem taper model offered the best fit for the four tropical species in most statistics. The Kozako2 model also consistently provided the best performance in the lack-of-fit statistics with the best SEE, \(\bar E\) and AMD in most of the relative height classes. These stem taper equations could help forest managers and researchers better estimate the diameter of the outside bark with any given height, merchantable stem volumes and total stem volumes of standing trees belonging to the four species of the tropical forest in MMFR.     

Effects of ocean acidification on the metabolic rates of three species of bivalve from southern coast of China

Oceanic uptake of anthropogenic carbon dioxide results in a decrease in seawater pH, a process known as "ocean acidification". The pearl oyster Pinctada fucata, the noble scallop Chlamys nobilis, and the green-lipped mussel Perna viridis are species of economic and ecological importance along the southern coast of China. We evaluated the effects of seawater acidification on clearance, respiration, and excretion rates in these three species. The animals were reared in seawater at pH 8.1 (control), 7.7, or 7.4. The clearance rate was highest at pH 7.7 for P. fucata and at pH 8.1 for C. nobilis and P. viridis. The pH had little effecton the respiration rate of P. fucata and P. viridis. In contrast, the respiration rate was significantly lower atpH 7.4 in C. nobilis. The excretion rate was significantly lower at pH 7.4 than pH 8.1 for all species. Theresults indicate that the reduction in seawater pH likely affected the metabolic process (food intake, oxygenconsumption, and ammonia excretion) of these bivalves. Different species respond differently to seawateracidification. Further studies are needed to demonstrate the exact mechanisms for this effect and evaluateadaptability of these bivalves to future acidified oceans.     

Alterations to biological soil crusts with alpine meadow retrogressive succession affect seeds germination of three plant species

Biological soil crusts (BSCs) are the important components of alpine meadow ecosystems. The extent and morphology of BSCs vary greatly with alpine meadow retrogressive succession due to grazing pressure. There is significant interest in impacts of crust composition on plant seed germination, especially in (semi-) arid environments. However, little is known about the influences of BSCs, and their associations with alpine meadow succession, on germination of typical alpine meadow vascular plant species. In a full factorial common-garden experiment, we studied effects of: (1) crust type, (2) seed position, and (3) surface texture on seed germination. We chose three typical alpine meadow plant species (i.e. Poa pratensis, Tibetia himalaica and Potentillen nivea), which belonged to different functional groups (graminoids, legumes, and forbs) and play important roles in all alpine meadow succession stages. Crust type and seed position influenced seed germination, and the inhibitory effects of BSCs depended on the crust type and seed species tested. The major factors influencing seed germination were BSC type, seed position, soil texture, and the interactions between BSC type and seed position; species and seed position; species and surface texture; and species, crust type, and surface texture. Cyanobacteria crust significantly inhibited germination of all seeds. Seed position also had a significant effect on seed germination (p < 0.001). Fewer seedlings germinated on the surface than below the surface, this was especially true for P. nivea. seeds within cyanobacteria and lichen crusts. Only germination rates of T. himalaica on the soil surface were significantly correlated with plant occurrence frequency within the alpine meadow community. The poor correlation for the other two species is possibly that they are perennials. Our results clearly demonstrated that BSCs can be biological filters during seed germination, depending on the BSC succession stage. Through their influences on seed germination, BSCs can strongly influence community assemblages throughout alpine meadow retrogressive succession.     

Identification of three common Loliginidae squid species in the South China Sea by analyzing hard tissues with geometric outline method

The hard tissues of squid can provide important information for species identification. In this study, we used statolith and beak to identify three squid species including Uroteuthis duvaucelii, Loliolus beka, and U. edulis in the South China Sea. Because of the highly overlapping habitat and similar body morphology of the three squid species, we explored four different ways to identify them, by using statolith, upper beak, lower beak and a combination of statolith and beak. An outline geometric morphometric method and stepwise discriminant analysis were used to evaluate the most suitable method for the identification. We found that the combination of statolith and beak had the highest cross validation rate that was 75.0%, 87.5% and 88.7% for U. duvaucelii, L. beka and U. edulis, respectively. Using two beaks had similar results and the lowest cross validation rate was 60.0%, 50.0%, and 73.7% for the upper beak, 46.9%, 58.5% and 75.3% for the lower beak of U. duvaucelii, L. beka and U. edulis, respectively. Analyzing with the statolith had moderate cross validation which was 72.2%, 80.0%, and 87.7% for U. duvaucelii, L. beka and U. edulis, respectively. From the results it is suggested when the entire body of a squid is available, a combination of statolith and beak should be used for the identification. When only one hard tissue is available, species identification can be subjected to large errors.     

Population dynamics of marine ciliate Euplotes vannus (Protozoa, Ciliophora) in different artificial seawaters

To study population dynamics of marine ciliates in different artificial seawaters (ASW), the population growth dynamics of a common marine ciliate Euplotes vannus were investigated using beef extract media and rice media for five types of ASW and natural seawater (NSW). The results show that: (1) the population growth rate was in the order of NSW>Flack ASW>Nakamula ASW>Schmadz ASW>Oshima ASW>Subow ASW and was considerably higher in rice media than in beef extract media (apart from Subow ASW); (2) the maximum density of E. vannus in stationary phase in each treatment was ranked as Flack ASW>Nakamula ASW>Schmadz ASW>NSW>Oshima ASW>Subow ASW, and was again higher in rice media than in beef extract media (except for Subow ASW); (3) the exponential and stationary phases were longer in rice media than in beef extract media; (4) strains of E. vannus that had been domesticated for >1 year in ASW grew significantly slower, with lower maximum density and longer stationary phase than those isolated and maintained in NSW. It was demonstrated that: (1) E. vannus may grow well in Flack, Nakamula and Schmads ASW compared with NSW (mainly in terms of growth rate); and (2) Oshima ASW is the preferred choice for stock cultures of E. vannus, but the ASWs Flack, Nakamula and Schmadz are preferred for mass culture. These findings suggest that these three ASWs are effective for the cultivation of marine protozoa for experimental studies on ecology, toxicology and molecular biology.     

Observations on a magnetotactic bacteria-grazing ciliate in sediment from the intertidal zone of Huiquan Bay,China

Journal of Oceanology and Limnology - Magnetotactic bacteria(MTB) are a group of prokaryotes having the ability to orient and swim along geomagnetic fi eld lines because they contain intracellular...