20d、18h山羊胚胎系统形态及以后各时期体形发生

２０ｄ、１８ｈ 山羊胎儿仍属鳃弓期，呈典型Ｃ字形，４ 对鳃弓发生，心胸突大于肝腹突，前肢芽、后肢芽均为丘状。前间、中脑泡及神经管均已产生完整；消化系统、循环系统、发育较快、各器官原基已产生；泌尿系统的后肾、生殖系统的性腺尚未发生。２０ｄ、１８ｈ ～２６ｄ 山羊胚胎为鳃弓期，４ 对鳃弓充分发育，在后期，前肢芽已由丘状变为桨状，肝腹突在后期超过心胸突，视泡、听泡、嗅窝均已发生；指蹼期：３０ｄ～３７ｄ ，虹膜产生，阴突产生，绒毛膜产生绒毛叶阜，肢芽尖端变为指状，指间有蹼膜，外观鳃裂已愈合；偶蹄期：３９ ～４７ｄ ，颈曲，背曲消失，乳腺原基初现，肢部分节，形成偶蹄；形成期与胎儿期：主要以体重增加，毛产生为特征。

Ontogenetic Changes in Meristic Measurements of Silver Carp and Bighead Carp

The study analyzed 30 exterior meristic characters for 255 silver and bighead carp samples of 1- to 5-year-old collected from the National Primary Breeding Farm at Laojianghe Lake at the Middle Reach of the Yangtze River. Multivariate analysis was performed. In silver carp, the Euclidean distance was the greatest between the 1-year-old group and other age groups. Silver carp individuals were correctly classified at 98.0% accuracy with a discriminant function established by discriminant analysis based on meristic measurements. Similarly, bighead carp had the greatest distance between 1- to 2-year-old group and other age groups. Individuals of bighead carp were correctly classified at 90.7% accuracy by the discrimination function. The data showed that morphological transformation occurred during the life history of silver and bighead carp development. Eighteen meristic measurements showed highly significant differences, while four showed a significant difference between the two silver carp groups. Ten parameters decreased, while twelve measurements increased during development. In bighead carp, fourteen parameters were significantly different, while three parameters were significantly different between the two groups. Twelve parameters were significantly decreased and another five were increased during development. The results suggest allometric growth should be taken into account when identifying species, analyzing population differences and establishing germplasm standards based on morphology.

Ontogeny and Metamorphic Patterns of Female Reproductive Organs of Ephedra sinica Stapf (Ephedraceae)

Ontogeny and metamorphic. development of female reproductive organs in Ephedra sinica Stapf were surveyed. At the end of April, female cones began to initialize from the vegetative buds. Pollination occurred in mid-May and seeds matured at the beginning of July. The ontogenetic pattern of female reproductive organs of E. sin ca is basically similar to that of E. distachya L. The foliar nature of the outer envelope of the ovule in Ephedra is corroborated. Reduction of ovule number as a tendency of speciation in the genus is substantiated by the occurrence of tri-ovulate cones coupled with comprehensive characters of the genus. The metamorphic patterns as well as the leaf nature of the outer envelope indicate that female cones of Ephedra are compound while the female reproductive units of the ovulate cone have been reduced from secondary reproductive shoots similar to those of cordaites by phylogenetic transformation, fusion and reduction. Each fertile bract together with its axillary female reproductive unit composed the Bract Scale and Seed Scale Complex of Ephedra.

Research advances in the biological characteristics of the crustacean spermatozoa

The biological characteristics of crustacean spermatozoa is important for the artificial reproduction and genetic breeding. With reference to the latest studies and related materials, this paper reviewed the research progress in the biological characteristics of crustacean spermatozoa, such as morphological structure of sperm, spermatogenesis, sperm viability, preservation in vitro and acrosome reaction et al. The prospects of the research field have also been anticipated.

CORAL AS A CARRIER FOR RECOMBINANT HUMAN BONE MORPHOGENETIC PROTEIN-2

By combining coral with recombinant human bone morphogenetic protein-2 (rhBMP-2), rhBMP-2/coral composite was obtained in this study. Following implantation of the composite into the muscle pouches of mice, cartilage growth was induced in the pores or on the surface of the implants at one week, woven bone at three week and lamellar bone with bone marrow at six week, and coral was absorbed partially. The induced formation of endochondral bone was time-related and rhBMP-2 dose-related. The results of this study indicate that the composite possesses a superior ability of osteogenesis, and coral acts as one of the most suitable rhBMP-2 slowrelease carriers currently available. The composite will be a new type of bone substitute to be used in orthopaedics and maxillofacial surgery.

Evolution of discocephalid ciliates:Molecular,morphological and ontogenetic data support a sister group of discocephalids and pseudoamphisiellids (Protozoa,Ciliophora) with establishment of a new suborder Pseudoamphisiellina subord.n.

Discocephalids and pseudoamphisiellids are possibly two of the most confused groups among hypotrichous/euplotid ciliates regarding their systematic position and phylogenetic relationships.The former were often regarded as related to euplotids while the latter,in the absence of molecular data,were mostly assigned to the urostylid-like hypotrichs.In the present work,the small subunit rRNA genes of several rarely observed discocephalid and pseudoamphisiellid genera were analyzed to obtain insights into the phylogenetic relationships of these highly ambiguous Spirotrichea.Four different tree reconstruction algorithms yielded nearly identical topologies,which indicated both groups belong to the same assemblage.This assemblage is clearly isolated as a deep-branching clade and invariably positioned between Euplotida and Hypotricha.The sister group relationship of the Pseudoamphisiellidae and Discocephalidae supports the previous suggestion that they might represent an ordinal taxon,the Discocephalida.Both morphological and morphogenetic features indicate that the pseudoamphisiellids should be placed in the order Discocephalida but as a sister group to other typical discocephalids.Thus we propose establishing a new suborder,Pseudoamphisiellina subord.n.The new taxon is diagnosed by the following characteristics:(i) two distantly separated midventral rows that are morphogenetically formed with an urostylid mode;(ii) absence of the "frontoterminal row",which is formed from the posterior-most frontoventral-transverse cirral anlage in all other typical urostylids;(iii) numerous caudal cirri that derive from each of the dorsal kinety anlagen;(iv) right marginal row that has a unique de novo origin;and (v) inhabiting periphytic communities.The validity of the suborder Pseudoamphisiellina is firmly supported by molecular data.

Expression of bone morphogenetic protein 2,4,and related components of the BMP signaling pathway in the mouse uterus during the estrous cycle

The objective was to investigate the expression of bone morphogenetic protein （BMP） family members in the mouse uterus during the estrous cycle by real-time polymerase chain reaction （PCR） and immunohistochemistry. Uterine samples from Swiss ICR mice were collected and dissected free of surrounding tissue. One uterine horn was snap frozen in liquid nitrogen immediately after collection and stored at -80 ℃for RNA extraction, and the other was fixed in 40 mg/ml paraformaldehyde at room temperature for immunolocalization of BMP2 protein. Real-time PCR analysis showed that the expression level of Bmp2 was significantly higher at proestrus than at estrus and metestrus （P〈0.05）. The relative abundance of Bmp4 exhibited significant fluctuations, but there were no statistically significant differences between the expression levels of Bmp2 and Bmp4 （P〉0.05）. The expression levels of Bmprla and Bmpr2 remained unchanged during estrous cycles. However, the level of Bmprlb mRNA decreased significantly at estrus （P〈0.05）, increasing subsequently at metestrus. Furthermore, the level of Bmprlb mRNA was significantly lower than those of Bmprla and Bmpr2 mRNA at the corresponding stages （P〈0.05）. All three receptor-regulated Smads （R-Smads） detected were differentially expressed in the mouse uterus and the expression levels of Smadl and Smad5 were significantly higher than that of Smad8 （P〈0.05）. In addition, the expression level of Smad4 did not change substantially throughout the estrous cycle. Immunohistochemical experiments revealed that BMP2 protein was differentially expressed and localized mainly in the uterine luminal and glandular epithelial cells throughout the estrous cycle. In conclusion, our results provide information about the variation in the mRNA levels of Bmp2 and Bmp4 and related components of the BMP signaling pathway. The data provide quantitative and useful information about the roles of endometrial BMP proposed and demonstrated by others, such as the degradation and remodeling of the endometrium.

Growth and morphological characterization of zinc nanoplates

Zinc nanoplates were grown using thermal evaporation without catalyst or template involved.Tunneling electron microscopy and selected area electron diffraction analyses showed that the plates were single crystals with either {0001} or {11 20} as basal surfaces.The morphological characteristics were explained in terms of the intrinsic growth anisotropy of zinc,the surface energy of the nano-crystals,the size of the critical nucleus and the migration of the adatoms.Our results suggested a promising low-cost route for synthesis of pure zinc nanoplates which could be used as precursor for further preparing core-shell nanoplate structures.