Ontogeny of IgM-producing cells in the mandarin fish Siniperca chuatsi identified by in situ hybridisation

The ontogeny of IgM-producing cells was studied in juvenile mandarin fish Simperca chuatsi, an important fish in China's aquaculture sector. The IgM-producing cells were localised through in situ hybridisation with a probe complementary to the Ig mu-chain in lymphoid-related tissues, including head kidney, spleen, thymus, intestine and gills. In head kidney, transcripts of Ig mu were first detected at 20 days post-hatching (dph) with a few positive signals. and the number of IgM-producing cells increased obviously from 39 dph onwards. At 136 dph, a large amount of positive cells were observed in the entire organ with clusters of these cells located around the blood vessels. In spleen, IgM-producing cells were found from 26 dph onwards, followed by an increase until 67 dph: clusters of positive cells were also detected around blood vessels at 102 dph. In thymus, IgM-producing cells were first observed at 39 dph; thereafter, no obvious increase was detected until 78 dph. The positive cells in thymus were distributed mainly in the outer zone of thymus. A few IgM-producing cells were still observed in thymus of 1-year-old mandarin fish. IgM-producing cells were not detected in the intestine until 87 dph, with several discrete positively stained cells distributed in the lamina propria. IgM-producing cells, scattered mainly in primary gill filaments around blood vessels, were detected in gills from 90 dph. As in other teleosts, these results indicated that the head kidney appears to be the primary organ for IgM production in mandarin fish, and IgM-producing cells exist in all organs examined in the present study, implying their lymphoid role in fish. In addition, it is suggested that vaccination after 20 dph may be much more effective in mandarin fish. (C) 2009 Elsevier B.V. All rights reserved.

The ontogeny of echolocation in a Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis)

Acoustic and concurrent behavioral data from one neonatal male Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis) in captivity were presented. The calf click train was first recorded at 22 days postnatal, and the frequency of hydrophone-exploration behavior with head scanning motions in conjunction with emissions of click trains by the calf increased gradually with age. The echolocation clicks in the first recorded click train were indistinguishable from those of adults. Calf echolocation trains were found to decrease in maximum click-repetition rate, duration, and number of clicks per train with age while the. minimum click-repetition rate remained more consistent. (c) 2007 Acoustical Society of America.

Early ontogeny of Ancherythroculter nigrocauda and effects of delayed first feeding on larvae

Development of embryos and larvae in Ancherythroculter nigrocauda Yih et Woo (1964) and effects of delayed first feeding on larvae were observed after artificial fertilization. The fertilized eggs were incubated at an average temperature of 26.5 degrees C (range: 25.7-27) and the larvae reared at temperatures ranging from 21.8 to 28 degrees C. First cleavage was at 50 min, epiboly began at 7 h 5 min, heartbeat reached 72 per min at 24 h 40 min and hatching occurred at 43 h 15 min after insemination. Mean total length of newly hatched larvae was 4.04 +/- 0.03 mm (n = 15). A one-chambered gas bladder was observed at 70 h 50 min, two chambers occurred at 15 days, and scales appeared approximately 30 days after hatching. Larvae began to feed exogenously at day 4 post-hatch at an average temperature of 24 degrees C. Food deprivation resulted in a progressive atrophy of skeletal muscle fibres, deterioration of the larval digestive system and cessation of organ differentiation. Larval growth under food deprivation was significantly affected by the time of first exogenous feeding. Starved larvae began to shrink, with negative growth from day 6 post-hatch. The point of no return (PNR) was reached at day 11 after hatching. Mortality of starved larvae increased sharply from day 12 after hatching.

低等金缕梅类的系统学：分子和发育学证据

传统的低等金缕梅类包含7个科，即领春木科（Eupteleaceae）、昆栏树科（Trochodendraceae）、水青树科（Tetracentraceae）、连香树科（Cercidiphyllaceae）、折扇叶科（Myrothamnaceae）、悬铃木科（Platanaceae）和金缕梅科（Hamamelidaceae）。这些科之间的谱系关系以及金缕梅科内部的谱系关系是研究被子植物系统和进化的主要问题之一。本研究的目的在于通过对现有的和本研究中产生的分子和发育学资料的分析来对这些谱系问题进行探讨，希望使我们对这些类群的认识提高到了一个新的水平。 本研究测定了包括连香树科、领春木科、悬铃木科、水青树科和金缕梅科内所有亚科代表共计14个种的rbcL基因，matK基因和18S-26S核核糖体（nrDNA）内转录间隔区（ITS）的序列，并结合原有资料对所有低等金缕梅类（除非洲分布的折扇叶科）及其相近类群进行了分支分析。主要结论包括;传统低等金缕梅类是一个复系类群;金缕梅科也是一个复系类群;ITS序列分析支持将连香树科包含在金缕梅科内，但是，rbcL资料和matK资料不支持将连香树科包含在金缕梅科内。本研究支持金缕梅科内6个亚科的分类系统，即将其分为阿丁枫亚科（Altingioideae）、红花荷亚科（Rhodoleioideae）、马蹄荷亚科（Exbucklandioideae）、壳菜果亚科（Mytilarioideae）、双花木亚科（Disanthoideae）和金缕梅亚科（Hamamelidoideae），但壳菜果亚科的山桐柴属（Chunia）应置于马蹄荷亚科内。 本研究首次描述和报道了金缕梅科5个亚科6个种的花的形态发生。通过对本研究发现的新证据和文献中记载的资料分析表明金缕梅科的花发育的特征无明显的共同式样。从本研究提供的花发育资料得出的值得注意的结论是红花荷属在金缕梅科中的亚科地位得到支持。对牛鼻栓（Fortunearia sinensis Rehd. et Wils.）的花发育研究表明其花性分化在发育晚期才出现。 本文首次对显脉红荷（Rhodoleia henryi Tong）的胚胎学进行了研究。尽管红花荷属是金缕梅科内适应鸟传粉的特化类群，但其胚胎学的特征与金缕梅科其它植物并无明显区别。因此，本研究不支持红花荷属独立成科而支持其在金缕梅科内的亚科地位。

中国麻黄属植物的分类——兼论麻黄属的演化

根据中国麻黄属植物分类及麻黄属起源和演化研究中存在的争论，本论文主要进行了分类学、形态学、微形态学、解剖学、形态发生学、孢粉学、古植物学、植物生态学和植物地理学等方面的研究。 1、分类学 从性状变异式样的分析入手，结合标本馆工作和野外调查，确认了中国麻黄属植物共有13个种;合并了丽江麻黄(Ephedra likiangensis)、雌雄麻黄(E. fedtschenkoae);澄清了前人在细子麻黄(E. regeliana)、灰麻黄(E. glauca)、草麻黄(E. sinica)和双穗麻黄(E. distachya)等种类鉴定中混乱的问题，并描述了一个新种——日土麻黄（Ephedra rituensis Y. Yang, D. Z. Fu et G. Zhu）。 2、形态学 提供了中国麻黄属种类的标本（包括模式标本）照片资料及中国麻黄属植物的雌球花和雄球花的照片资料，为麻黄属分类和系统学研究提供了证据。 3、微形态学 首次报道了中国麻黄属植物的种子表面微形态特征，聚合囊表面纹饰、小枝表面特征。 种子表面特征可分为4种类型。类型I：种子表面平滑，包括：中麻黄(Ephedra intermedia)、双穗麻黄、细子麻黄等;类型II：种子表面具疣状突起，仅发现木贼麻黄(E. equisetina)一种;类型III：种子表面具横向片层状突起，仅有斑子麻黄(E. rhytidosperma)一种;类型IV：种子表面具纵条纹，包括喜马拉雅特有的3个大种子的种类，即矮麻黄(E. minuta)、山岭麻黄(E. gerardiana)和藏麻黄(E. saxatilis)。 对小枝表面扫描电镜下的微形态构造的研究并没有发现前人报道的毛状体特征，而只有一些疣状角质突起和有变异的气孔，同时注意到，麻黄属植物的小枝表面特征受到生境、发育阶段的影响。 麻黄属聚合囊顶孔开口处具脑波状纹饰，而聚合囊表面纹饰具二级纹饰。麻黄属聚合囊表面纹饰非常独特，为该属在地层中雄性生殖构造的发现提供了可参考的性状。 4、孢粉学 补充了麻黄属中非常特化的种——斑子麻黄的孢粉资料，同时也对膜果麻黄(Ephedra przewalskii)、中麻黄、细子麻黄和木贼麻黄的孢粉重新进行了研究。结果表明斑子麻黄的花粉形态也非常特殊，其纵肋数目5条左右，纵肋波状扭曲，肋间沟槽内透明线发达且分枝。膜果麻黄的花粉与前人描述的一致，但是，中麻黄、细子麻黄和木贼麻黄的花粉形态可能受到发育的影响而与前人报道中描述的有些差异。讨论了麻黄属4种花粉类型的演化趋势。 5、形态发生学 对麻黄属雌球花三种代表类型的个体发育研究表明，三胚珠球花发育早期球花主轴的顶芽发育，双胚珠球花的顶芽没有发育，而在单胚珠球花中，雌性生殖单位直接占据顶芽的位置发育。这三种类型也代表了麻黄属球花演化的三个阶段，三胚珠球花代表麻黄属雌球花的原始式样，而单胚珠雌球花则为麻黄属雌球花最为特化的式样。总之，麻黄属雌球花有简化的趋势，伴随着这种趋势，雌球花苞片数目减少、种子数目减少、种子体积增大、表面复杂度增加。 6、解剖学 对斑子麻黄种子表面微构造的形态发生及解剖研究表明，斑子麻黄雌性生殖单位发育早期，其表面为平滑型，因此，突起为次生的。这些突起是由雌性生殖单位外盖被表皮细胞的外壁向外突出形成，这种突出生长常常在相邻细胞之间同时发生，因此，出现片层状构造。石蜡切片显示，这些突起在发育早期有完整的细胞核、细胞质等结构，但在种子发育晚期和成熟后，这些外壁突起的细胞成为空腔隙，本文对这种构造的生态学意义进行了分析。 7、古植物学 本文描述了早白垩麻黄科的2个大化石种。 古斑子麻黄（Ephedra archaeorhytidosperma Y. Yang, B. Y. Geng et D. L. Dilcher et Z. D. Chen）发现于辽西义县组尖山沟层，时代为早白垩的芭雷姆期。该种的雌球花具2对苞片、1或2枚种子、珠孔管短直或顶部稍弯、种子表面具横列片层状纹饰等特征而与现存的斑子麻黄特征最为相近。二者之间如此多的相似之处只有一种解释，那就是它们曾经有过共同祖先。因此，该种应归属于麻黄属的肉苞组。古斑子麻黄雌球花特征的稳定性同时也表明，在麻黄属中也存在所谓的“形态演化停滞现象（morphological stasis）”，而这种现象也是首次在买麻藤类植物中报道。 星学异麻黄（Alloephedra xingxueii J. R. Tao et Y. Yang）产于吉林大拉子组，时代属早白垩的阿普特期——阿尔布期。该种雌球花具2对苞片、2枚种子，种子长椭圆形且具短的珠孔管与现存麻黄科植物最为相近，但是，其分枝式样与麻黄属不同，因此，本文在麻黄科中建立了一新属新种。此外，麻黄科植物常被看作是干旱区植被的代表，但是，对星学异麻黄当时所处的环境研究发现，大拉子组当时具有较明显的亚热带气候条件下的植被性质，因此，星学异麻黄即使需要干旱的条件，可能也只是局部小生境的条件。 8、生态学和植物地理学 本文首次对麻黄属植物生存环境中的水热条件进行了调查。从所选择的8个分布点来看，除了拉萨外，在麻黄属生殖生长期，其余7个分布点的湿度均是一年中最底的时期，而温度在这个时期逐渐升高。 对各地区内麻黄属种类的分布情况的分析发现，麻黄属的种类主要集中在三个地区，一是我国西北、前苏联的中亚地区及邻近地区，二是美国西南部、墨西哥西北部的地区，三是南美的智利、阿根廷等地。