APPEARANCE PATTERN OF TOOTH GERMS WITH DEVELOPMENTAL PROCESS IN MYLOPHARYNGODON PICEUS

The pharyngeal dental formula of Mylopharyngodon piceus is 4-5 as a rule, and the dentition isasymmetrical. It is difficult to identify each tooth in the larval dentition. In this paper the appearancepattem of tooth germ with developmental process in this fish is described in detail. The formationpattern of the left dentition is contrasted with that of the right one. In the developmental process,the left pharyngeal dentition lacks teeth at position An3. Thus the left dentition is D-type as designatedby Nakajima(1984), while the right one is A-type.     

Morphological changes in development of pharyngeal teeth inMylopharyngodon piceus

Adult pharyngeal teeth inMylopharyngodon piceus are molariform. Based on SEM observations of the developing teeth, this paper describes the morphological diversification of pharyngeal teeth inM. piceus. The larval and juvenile teeth are changed from conical to adult molariform teeth through seven stages. Comparisons are made between each stage and corresponding types in some species of different subfamilies in Cyprinidae. It is considered that the ontogenetic resemblances of the pharyngeal teeth bear relationship to the phylogeny of cyprinids. This project was funded by the International Cooperation of Japan—China and the National Natural Science Foundation of China     

陕西首次发现南方象化石

在陕西省澄城县采集到一对保存相当完好的南方象第三上臼齿化石。我国关于南方象化石的报导不多,在陕西省则是首次发现。这一发现对了解更新世时期南方象在我国的分布提供了新资料。     

Plateau typeE(%)- pH curves of interfacial exchange between liquid and solid in seawater

A study on the curves of the exchange ratioE(%)- pH on the liquid-solid interface of the systems Zn (II) with clay minerals, (Kaolinite, illite and montmorillonite), Zn (II) with hydrous ferric oxides (amorphous ferric oxide, geothite and hematite), Zn (II) with hydrous manganese oxide (γ-MnOOH, manganite and δ-MnO₂) etc. in seawater resulted in the discovery of new plateau type exchange ratioE(%)-pH curves not yet reported in literature. The two factors that decide the growth, decline and the change of the “plateau type” curve are: (1) the inherent characteristics of systems, which can be explained by the exchange constants (i=1, 2, 3, etc.) of interfacial stepwise ion/coordination particle exchange between liquid and solid; and (2) . The theory of interfacial stepwise ion/coordination particle exchange in seawater was applied to explain the experimental results of the above study and a general formula was derived for the plateau type exchange ratioE(%)-pH curves. The theoretically simulated and calculated curves coincided well with the experimental results. This paper provides new and powerful experimental basis to support the theory of interfacial stepwise ion/coordination particle exchange in seawater. The project was supported by the National Natural Science Foundation of China.     

CYTOLOGICAL COMPARISON OF GAMETOGENESIS OF SCALLOPS, ARGOPECTEN IRRADIANS AND CHLAMYS FARRERI

Histological characteristics of gametogenesis of two kinds of scallops, gonochoric Chinese scallop, Chlamys farreri and hermaphroditic bay scallop, Argopecten irradians were investigated in this study. Spermatogenesis in C. farreri has different developmental stages: spermatogonia, primary spermatocyte, second spermatocyte, spermatid and spermatozoon. A large number of same developmental stage spermatic cells converge at a definite area of the testis. Premeiotic, previtellogenic and vitellogenic oocytes can be found during oogenesis in C. farreri, where oocyte distribution is obviously irregular. The A. irradians gonad consists of two different parts in one individual: one part functions as testis, the other as ovary. Between these two parts is a special appearance area, where a large number of spermatic cells are bound with two layers of acellular substance with many oocytes in it.     

A new species of ciliates,Hemiophrys polymicronuclei sp. nov. from Donghu Lake,Hubei province

A new species of ciliatesHemiophrys polymicronuclei sp. nov. from Donghu Lake is described. It is characterized by its colorless to yellowish, soft, flat and spindle-shaped body with four micronuclei. The right side of the body is a little more convex than the left side, and more transparent at both anterior and posterior ends. Its slit-like cytostome accounts for 1/4 of the body length on the left side without any trichocyst. There are two rows of trichites near the right anterior end, 6–8 straight bristles on the pellicle opposite the cytostome, 23–25 rows of kinetides on the right side of the body, two ellipsoid macronuclei and many contractile vacuoles in the cytoplasm.     

Molecular identification of Prorocentrum (Dinophyceae) species

A fragment of a large sub-unit ribosomal DNA (LrDNA) of 12 strains ofProrocentrum species was amplified by polymerase chain reaction (PCR). The PCR products were digested by 3 restriction endonucleases (Cfo I, Hae III, and RSA I) and then resolved in agarose gels. Results show that different species had different RFLP patterns, except forP. arcuatum (ME 131), which had the same pattern toP. micans (ME160 and 04). The same fragment of 19 strains of the genus was also amplified and subjected to denaturing gradient gel electrophoresis (DGGE). 11 different patterns were resolved. Different cultures of a same species had the same pattern. The results of RFLP and DGGE analyses showed that eight newly isolated epibenthicProrocentrum species were different from each other, and also from other cultured ones examined in this study.P arcuatum (ME132) could not be differentiated fromP. micans (ME160 and 04), it was probably mis-identified, since they are quite different morphologically.P. redfieldii (ME138) could also not be distinguished formP. triestinium (ME132), it should be regarded as a synonym ofP. triestinium. Unexpectedly, a restriction site was found inP. micans, compared with previous sequence data. Project supported by National Basic Research Priorities Program (2001CB409701, 2001CB409710) and supported by NSFC (40376040, 40025614)     

The hydrogen peroxide impact on larval settlement and metamorphosis of abalone <Emphasis Type="Italic">Haliotis diversicolor supertexta</Emphasis>

Abalone Haliotis diversicolor supertexta is an important economic mollusk. The settlement and metamorphosis are two critical stages during its development period, which has direct influence on abalone survival and production. The influence of reactive oxygen species （hydrogen peroxide） on abalone embryo and juvenile development were examined in this study. Larvae of Haliotis diversicolor supertexta were induced to settlement and metamorphose by exposure to seawater supplemented with hydrogen peroxide. They had the best performance at 800 μmol/L. The concentration of 1 000 μmol/L or higher was toxic to the larvae, as the larvae could settle down only at benthic diatom plates without complete metamorphosis. In addition, H2O2 adding time was critical to the larval performance. 24h after two-day post-fertilization was proved to be the optimal adding time. In this paper, two action mechanisms of hydrogen peroxide are discussed： （1） hydrogen peroxide has direct toxicity to ciliated cells, thus cause apoptosis; （2） hydrogen peroxide, as a product from catecholamines＇ autoxidation process in vivo, can reverse this process to produce neuro-transmitters to induce abalone metamorphosis.     

A NEW SPECIES OF RANINOIDES （CRUSTACEA ： DECAPODA ： RANINIDAE） FROM OFF THE SOUTHEASTERN COAST OF HAINAN ISLAND AND NANSHA ISLANDS

Ranlnoides longifions new species, off SE coast of Hainan Island, dorsal surface of carapace with an arched granular edge across carapace between the anterolateral teeth, median frontal tooth longest, second frontal teeth subquadrate.     

Notes on Two Marine Ciliates from the Yellow Sea,China： Placus salinus and Strombidium apolatum（Protozoa, Ciliophora）

The living morphology and infraciliature of two rare marine ciliates, Placus salinus Dietz, 1964 and Strombidium apolatum Wilbert and Song, 2005, collected from the coastal waters near Qingdao, China, were investigated by in vivo observation and protargol impregnation technique. The improved diagnosis for Placus salinus is as follows: medium-sized marine Placus, in vivo (50–60)μm×(30–40)μm; cell elliptical to barrel-shaped; 28–31 somatic kineties; single macronucleus usually ellipsoid and one micronucleus located in the indention of the macronucleus; one contractile vacuole posteriorly positioned. Strombidium apolatum is characterized by: marine strombidium (40–60)μm×(30–45)μmm in vivo, cordiform in shape with somewhat pointed posterior end and conspicuous apical protrusion; extrusomes prominent, about 15μm in length and evenly arranged along the circle kinety; about 16 collar and 5–6 buccal membranelles; one elongate macronucleus and one micronucleus; circle and ventral kineties consisting of about 53 and 45 dikinetids respectively.     

The effect of temperature on growth and energy budget of the polychaete, Neanthes japonica Izuka

Growth and energy budget of the polychaete, Neanthes japonica, at various temperatures (17, 20, 23, 26 and 29°) were investigated in this study. The growth, as indicated by final dry weight and specific growth rate (SGR), increased with increasing temperature, with the maximum level at 26°C, and then decreased significantly at 29°C. A similar trend was observed in feeding rate, food conversion efficiency (FCE) and apparent digestive rate (ADR). However, no significant differences were detected in ADR among all the temperature treatments. In the pattern of energy allocation, faeces energy was only a small component of energy budget and had little influence on the proportion of food energy allocated to growth. The metabolic energy accounted for a large portion of energy intake for each temperature treatment. The nitrogen excretion was appreciable with changing temperature. The two expenditure terms (respiration energy and excretion energy) in energy budget were the major factors influencing the proportion of food energy allocated to growth. These results revealed that temperature affected the growth of N. japonica mainly by influencing feeding rate and FCE. In addition, regression equations describing the relationship between feeding rate, faecal production, SGR, FCE and temperature were obtained. The optimum temperatures for feeding rate, FCE and SGR were estimated at 25.01°C, 24.24°C and 24.73°C, respectively, from the regression equations.     

Population identification of red-fin pargo,Parargyrops edita Tanaka,in Taiwan strait and Beibu Gulf

This paper deals with population identification ofParargyrops edita Tanaka. Samples of spawning stocks were collected from Niushan-Penghu, Minnan-Taiwan shoal (Southern Fujian-Taiwan shoal) and Beibu Gulf during the spawning period 1981–1982. Morphological characters, both meristic and morphometric, are counted and measured respectively. The stock concept and intraspecific categories have been discussed. Some meristic characters as the number of left or right ventral fin spine, right ventral fin rays and abdominal vertebrae of this fish may be constant, others as the numbers of left or right pectoral fin rays and gill-rakers may have obvious geographical variation. Morphological characters have not attained the level of subspecific distinctness, no sub-species could be found among these stocks by means of coefficient of difference (C.D.). Basing upon the comparative analysis ofM _diff, the authors consider that stocks of Minnan-Taiwan shoal and Niushan-Penghu belong to the same local population, Taiwan Strait local population. By means of the discriminant function analysis and linear relationship analysis, statistical differences will be found to exist in meristic characters between the stock of Minnan-Taiwan shoal and that of Niushan-Penghu, so that the two are virtually different stocks or subpopulations. The stock of Beibu Gulf belongs to another called the Beibu Gulf local population. These two local populations are of allopatric distribution and show statistically significant difference between themselves. Among these stocks, the Minnan-Taiwan shoal stock is strongly influenced by the much more complicated environmental conditions of the mixed boundary region of the subtropical Sino-Japanese Subregion in the north and the tropical Indo-Malayan Subregion in the south. Thus its coefficient of variability (C.V.) is greater than those of the other two in the mean values of various meristic characters. This paper was published in Chinese inOceanologia et Limnologia Sinica 14 (6): 511–520.     

Reevaluation of cortical developmental patterns in Euplotes (s. l.), including a morphogenetic redescription of E. charon (Protozoa, Ciliophora, Euplotida)

We documented the pattern of cell development in Euplotes charon. The ontogenesis of this species was similar to many of its congeners, except for the formation of the caudal cirri. In E. Charon, a caudal cirrus is formed posterior to each of the rightmost two or three dorsal kinety anlage in the proter, and the second rightmost dorsal kinety in the opisthe. In addition, two caudal cirri are formed posterior to the rightmost dorsal kinety in the opisthe. This pattern of development represents a completely new type. Based on our evaluation, and in comparison with previous studies, we also conclude that the pattern of cell development is variable among species in the Euplotes genera. The variation is particularly evident during the formation of frontoventral and caudal cirri. Based on the segmentation pattern of frontal-midventral transverse cirral anlagen, cirri reduction, and migration of frontoventral cirri, we identified five types: the affinis-type, the eurystomus-type, the charon-type, the raikovi-type and orientalis-type. Euplotes (s. l.) can also be divided into three types based on the formation of caudal cirri: focardii-type, vannus-type and charon-type. Indeed, we conclude that the number (one or two) of marginal cirri should be given as much consideration as the genetic separation. Given this, we reassessed the validity of using genetic separation to classify the group. Generally, the morphogenetic data disagreed with the molecular data (SSrRNA gene sequences). Given these discrepancies, it is too early to draw conclusions on the systematic arrangement of this species-rich taxon.     

Expression and localization of a novel phosducin-like protein from amphioxus <Emphasis Type="Italic">Branchiostoma belcheri</Emphasis>

A full length amphioxus cDNA, encoding a novel phosducin-like protein (Amphi-PhLP), was identified for the first time from the gut cDNA library of Branchiostoma belcheri. It is comprised of 1 550 bp and an open reading frame (ORF) of 241 amino acids, with a predicted molecular mass of approximately 28 kDa. In situ hybridization histochemistry revealed a tissue-specific expression pattern of Amphi-PhLP with the high levels in the ovary, and at a lower level in the hind gut and testis, hepatic caecum, gill, endostyle, and epipharyngeal groove, while it was absent in the muscle, neural tube and notochord. In the Chinese Hamster Ovary (CHO) cells transfected with the expression plasmid pEGFP-N1/Amphi-PhLP, the fusion protein was targeted in the cytoplasm of CHO cells, suggesting that Amphi-PhLP is a cytosolic protein. This work may provide a framework for further understanding of the physiological function of Amphi-PhLP in B. belcheri. Supported by the Pilot Projects of Knowledge Innovation Project of Chinese Academy of Sciences (No. KZCX2-YW-211-03 and MGE2008KG06)     

ENCLOSURE EXPERIMENTS ON AND LACUSTRINE PRACTICE FOR ELIMINATING MICROCYSTIS BLOOM

Microcystis bloom, one of the most objectionable characteristics of eutrophication in tropical and subtropical waters, occurred in Donghu Lake (East lake) of Wuhan every summer from the 1970s up to 1984, but from 1985 up to now failed to occur there. The cause of its disappearance rema-ined in obscurity until recently. In situ enclosure experiments in the lake for three years showed that the stocking of the filter-feeding silver carp ( Hypophthalmichthys molitrix ) and big-head carp (Aristichthys nobilis ) played a decisive role in eliminating Microcystis bloom from the lake; but that recurrence of the bloom is possible under certain conditions. This paper presents the details and the results of enclosure ex-periments. The authors‘ analysis of fish biomass data obtained by echo-sounding and the fishery produc-tion of the lake over the years, revealed that the recurrence of Microcystis bloom can be prevented so long as the combined biomnss of silver carp and big-head carp remains at or exceeds 50 g per cubic meter of lakewater, as was the case in the lake‘s 1985 fish yield of 1015 t.     

DISTRIBUTION AND POPULATION DYNAMICS OF PARACALANUS PARVUS,PRACALANUS CRASSIROSTRIS,AND ACARTIA BIFILOSA（COPEPODA,CALANOIDA）IN THE BOHAI SEA

Paracalanus parvus,Paracalanus crassirostris,and Acartia bifilosa are dominant and widely distributed in the Bohai Sea,and comprise an important part of zooplankton in terms of biomass as well as production rate.In order to understand their seasonal distribution and population dynamics,their stage-specific abundance in different months of the year were analyzed based on the never analyzed yet samples collected in 1959.The three species showed clear and remarkable seasonal variation in abundance,which maximized in spring and summer,when they formed high biomass patches or concentrations in the nearshore area.For Paracalanus parvus,two peaks were observed in the annual circle,one in June and the other in September,For Paracalanus crassirostris,one peak occurred in summer and a small one in December.The seasonal pattern of Acartia bifilosa was different in different regions.In Bohai Bay it had a two-peak pattern,with the first large peak occurring in May and the second one in October.In Laizhou Bay,a winter peak in December and January could be observed besides the spring one.The number of generations during the reproductive season for the three species was estimated based on the annual cycle in abundance and ambient temperature.     

A new free-living marine nematode species of Rhinema from the South China Sea

A new free-living marine nematode species of the genus Rhinema belonging to the family Monoposthiidae was collected from marine sediments in the Qiongzhou Strait of the South China Sea,and it is described here as Rhinema longispicula sp.nov.The new species is characterized by coarsely annulated cuticle with 12 longitudinal ridges(alae) marked as reversed V-shaped.The first and second annuli broader and form a kind of a cephalic capsule.The amphideal fovea circular,situated in the middle of the broad second annulus,not surrounded by dense annulations.Buccal cavity cylindrical with a large dorsal tooth.Pharynx with a prominent anterior pharyngeal bulb and an elongated terminal bulb.Elongate spicules strongly curved,with cephalated proximal end and pointed distal end.Gubernaculum boat-shaped,without apophysis.A long and blunt precloacal seta present.Female with two opposed,outstretched ovaries.     

NEW OBSERVATIONS ON THE MEIOTIC PROCESS IN THE MARINE DINOFLAGELLATE NOCTILUCA SCINTILIANS （NOCTILUCALES, DINOPHYCEAE）

The meiotic process in Noctiluca scintillans were observed under light microscope.Some abnormal cell divisions, incompletely separated “zoospores” and the changes of the zoospores are described in this paper. Together with the fmdings of field samplings and the previous results by other researchers, the process of meiosis in N. scintillans was supposed to be a pathway to reduce the extra high density of NH3-N within the cell in order to ensure normal population growth.     

Comparative studies of inorganic carbon utilization inEmiliania huxleyi and some non-calcifying marine microalgae

Inorganic carbon utilization in the non-calcifying marine microalgae,Nannochloropsis oculata, Phaeodactylum tricornutum andPorphyridium purpureum was compared with high- and low-calcifying strains ofEmiliania huxleyi grown in artificial seawater medium aerated with either air (0.03% V/V CO₂) or CO₂-free air. For high-calcifying strain ofE. oculata andP. tricornutem, similar growth patterns were observed in air-and CO₂-free air-grown cultures.P. purpureum showed a less final cell density in CO₂-free air than in air-grown culture. However, low-calcifying strain ofE. huxleyi was able to grow only in air-grown culture, but not in CO₂-free air-grown culture. Measurements of alkalinity, pH, concentration of dissolved inorganic carbon (DIC) and free CO₂ showed different patterns of DIC utilization. WithN. oculata, P. tricornutum andP. purpureum the pattern of DIC utilization was characterized by an increase of pH and a decrease of DIC but a constant alkalinity in the cultures aerated with air or CO₂-free air, suggesting that bicarbonate utilization was concomitant with an efflux of OH⁻. Both alkalinity and pH were maintained rather constant in air-grown culture of low-calcifying strain ofE. huxleyi, suggesting that diffusive entry of CO₂ could meet the requirement of DIC for its photosynthesis and growth. High-calcifying strain ofE. huxleyi, however, showed a pattern of decrease of alkalinity and DIC but an almost constant pH, indicating that bicarbonate was the major form of inorganic carbon utilised by this organism and bicarbonate uptake is unlikely to be accompanied by an efflux of OH⁻. The final pH values reached byN. oculata, P. tricornutum andP. purpureum in a closed system were 10.75, 10.60 and 9.85 respectively, showing that bicarbonate utilisation is concomitant with an efflux of OH⁻. While the final pH of 8.4 in high-calcifyingE. huxleyi suggests that bicarbonate utilization was not accompanied by an efflux of OH⁻. Contribution No. 3557 from the Institue of Oceanology, Chinese Academy of Sciences. This work was supported by NERC grant GRE3/7853 U. K. and partly supported by Bio-Engineering Center, SSTC 96-C01-05-01.