鳗鲡繁殖生物学研究 Ⅱ.下海雌鳗脑垂体超显微构造的研究

神经垂体主要由神经分泌纤维、脑垂体细胞和微血管组成。神经分泌纤维主要是无髓鞘神经纤维,也有一些是有髓鞘神经纤维。神经垂体中还有一些多层体构造。神经分泌纤维有两个基本类型:A型纤维含有直径为1250—1750Å的神经分泌颗粒;B型纤维含有直径为450—1000Å的颗粒状囊泡。腺垂体的分泌细胞按其超显微构造的特点和所含的分泌颗粒大小不同可以区分为六个类型:催乳激素分泌细胞、促甲状腺激素分泌细胞,促肾上腺皮质激素分泌细胞、促生长激素分泌细胞、促性腺激素分泌细胞和后腺垂体的分泌细胞。       

垂体前叶内神经纤维可能参与ACTH分泌的调节

我们建立了垂体组织块短时温育并施加电场刺激的离体实验体系,运用此方法并结合放射免疫测定激素含量,观察了大鼠垂体前叶内神经纤维对促肾上腺皮质激素（ＡＣＴＨ）释放的影响。结果表明,电场刺激能够促使垂体前叶ＡＣＴＨ释放显著增加,刺激参数为强度３０ｍＡ,波宽０．５ｍｓ,频率１０Ｈｚ。这个效应可为温育液中加入河豚毒素（ＴＴＸ）和藜芦碱所阻断,但ＴＴＸ不能阻断精氨酸加压素（ＡＶＰ）诱发的ＡＣＴＨ分泌。同样参数的电场刺激对分散培养的大鼠垂体前叶细胞ＡＣＴＨ的分泌没有显著作用。以上结果说明,我们所用参数的电场刺激产生的效应是兴奋了垂体前叶内的神经纤维,而非直接刺激腺细胞所致。上述结果提示：垂体前叶激素分泌的调节除了传统的体液途径之外,还可能存在直接的神经控制。     

电场刺激对离体温育垂体前叶促肾上腺皮质激素分泌的影响

本实验应用离体温育大鼠垂体前叶组织块结合电场刺激及放射免疫测定方法,观察了垂体前叶内的神经纤维兴奋对促肾上腺皮质激素（ＡＣＴＨ）分泌的影响以及其它因素的作用。结果表明,一定参数的电场刺激使温育的大鼠四分之一垂体前叶组织块ＡＣＴＨ分泌增加,能被河豚毒素（ＴＴＸ）和藜芦碱部分阻断,此效应也可被地塞米松显著抑制,而同一参数的电场刺激与促肾上腺皮质激素释放激素（ＣＲＨ）诱发的ＡＣＴＨ分泌没有相互作用。经典神经递质受体阻断剂阿托品、心得安、酚妥拉明对电场刺激诱发的ＡＣＴＨ分泌没有显著影响;ＧＡＥＡ＿Ａ受体拮抗剂荷包牡丹碱明显促进此效应。该作用不受Ｐ物质拮抗剂ｓｐａｎｔｉｄｅ的影响,而降钙素基因相关肽（ＣＧＲＰ）受体拮抗剂ＣＧＲＰ片段８－３７能部分阻断这一作用。上述结果提示电场刺激所诱发的ＡＣＴＨ分泌可能部分由垂体前叶内ＣＧＲＰ能神经纤维介导。     

扬子鳄小肠壁神经丛内含AChE及SOM神经元的组织化学和免疫组织化学观察

本实验分别应用显示乙酰胆碱酯酶（ＡＣｈＥ）和生长抑素（ＳＯＭ）的组织化学和免疫组织化学方法,对扬子鳄小肠神经丛进行了研究。结果显示;ＡＣｈＥ阳性神经纤维广泛分布于肠壁神经丛内;粘膜下丛和肌间丛可见到许多ＡＣｈＥ阳性神经元,胞体大小不等形态不一。生长抑素免疫反应（ＳＯＭ－ＩＲ）纤维主要分布在肌间神经丛,ＳＯＭ－ＩＲ纤维大体呈两种类型：即较多的膨体状神经纤维和少量的细长神经纤维。粘膜下丛和肌间丛可见ＳＯＭ－ＩＲ阳性神经元,有时尚可见突起与周围神经纤维联系。提示低等脊柱动物两栖爬行类一扬子鳄内脏已存在比较完善的神经调节。     

N-乙酰天门冬氨酰谷氨酸免疫反应神经纤维在犬垂体后叶的分布

N-乙酰天门冬氨酰谷氨酸(NAAG)是一种日渐被重视的神经二肽,它在中枢神经系统的某些感觉和运动通路中可作为神经递质或调质起作用。本文应用免疫组化方法观察了 NAAG反应阳性神经纤维在犬垂体后叶的分布。正常犬垂体后叶仅有少量 NAAG 反应纤维。NAAG 反应纤维较细、较直,部分染色较浅,其上膨体小而稀;部分染色深、有较密、较大的膨体。NAAG 反应纤维在垂体后叶分布局限,在靠垂体柄部有很少量经柄而来的纤维,其他区域仅偶见有数根纤维。另外,在正中隆起背部有较多 NAAG 反应纤维及少数 NAAG 反应细胞,其纤维可沿正中隆起入垂体柄入垂体后叶。本实验结果显示:犬垂体后叶有少量 NAAG 反应纤维,这些纤维经正中隆起、垂体柄入垂体后叶。     

大鼠垂体前叶中的TH-,ChAT-免疫阳性神经纤维

长期以来,人们一直认为垂体前叶腺细胞没有直接神经支配,前叶内只有自主神经纤维支配垂体前叶的血管。本文在大鼠垂体的相邻切片上,应用免疫组织化学技术,对前叶中的儿茶酚胺的特征性酶——酪氨酸羟化酶（ＴＨ）和乙酰胆碱的特征性酶——胆碱乙酰转移酶（ＣｈＡＴ）进行显色。结果显示,大鼠垂体前叶中存在着ＴＨ－和ＣｈＡＴ－免疫阳性神经终末,两者可同时分布于垂体前叶的同一区域,且有较多终末分布于腺细胞周围。本文提示：儿茶酚胺和胆碱能神经纤维有可能直接调节腺细胞的活动     

大鼠脑内血管的单胺能神经分布——免疫组织化学法研究

本实验应用ABC免疫过氧化物酶法,以酪氨酸羟化酶(TH)作为标记物,观察了10只Wistar大鼠脑实质内血管的中枢去甲肾上腺素能神经分布。脑实质内血管壁明显可见免疫反应阳性去甲肾上腺素能神经纤维。对端脑皮质、海马、下丘脑、脑桥、延髓各部位血管的神经形态进行了描述。皮质血管的阳性纤维数量较多,纤维较细,相互交织成网,膨体可见;髓质内血管的阳性纤维较稀,似线样结构。讨论了中枢去甲肾上腺素能神经对脑实质内血管以及局部脑循环的作用。     

哺乳动物脑下垂体前叶的直接神经调节

内分泌系统的活动受神经系的调节。脑下垂体前叶,作为内分泌系的核心器官,其神经调节历来是神经内分泌学的一个中心课题。早期对于垂体前叶的神经支配有过大量的研究,从无神经支配、仅有少量神经纤维到有较丰富神经,众说不一。多数认为这些神经纤维属血管运动性,主要来自交感神经系。也有从下丘脑发出大量神经纤维到垂体前叶的报告。Ha-     

长鬣蜥脑垂体的组织学结构观察

用HE、尼氏染色和Holmes银染法对长鬣蜥脑垂体的显微结构进行了观察.发现其脑垂体分腺垂体、神经垂体两部分,为背腹型.HE染色观察到腺垂体分为嗜酸性细胞、嗜碱性细胞和嫌色细胞3种类型,另外还观察到室管膜细胞和神经垂体内的垂体裂;尼氏染色显示神经垂体的赫令氏体以及排列致密的腺垂体中间部细胞;Holmes银染法显示神经垂体的无髓神经纤维、垂体门脉系统的血管.首次发现垂体裂与中脑视叶的水管系统相连通.     

乌龟脑垂体显微及其腺垂体超微结构的研究

乌龟脑垂体由柄形神经垂体和椭圆形腺垂体两部分组成,神经垂体位于腺垂体后部上方呈背腹型排列。神经垂体中神经叶不发达,腺垂体分为远侧部和中间部,特殊空泡结构成为垂体门脉系统的特征。远侧部细胞分为嗜酸性细胞、嗜碱性细胞和嫌色细胞3种。通过透射电镜观察,腺垂体远侧部主要有5种分泌激素细胞:即生长激素(GH)分泌细胞、催乳激素(PRL)分泌细胞、促甲状腺激素(TSH)分泌细胞、促肾上腺皮质激素(ACTH)分泌细胞、促性腺激素(GTH)分泌细胞和非分泌类型滤泡-星形细胞(FS)。生长激素分泌细胞核大、分泌颗粒少的特征成为乌龟与其他动物最大的区别,可能与乌龟具有生长慢、寿命长的生物学特性有关。       

Materials for Chinese Phyllanthoideae

The present paper is part of taxonomic study on Chinese Phyllanthoideae. Included in it are two new varieties, Leptopus esquirolii var. villosus and Drypetes hainanensis var. longistipitata, one new combination, Glochidion triandrum var. siamense, and seven new records in China: Drypetes salicifolia, D. hoaensis. Actephila subsessilis, Glochidion khasicum, G. nubigennum, Bridelia spiosa and B. poilanei. In addition, seventeen taxon names are newly reduced: Liodendron formosanum = Drypetes formosana, Liodendron matsumurae = Drypetes matsumurae, D. longipes = D. indica, Antidesma paxii = A. acidum, A. hiiranense, A. filipes and A. pentandrum var. hiiranense = A. japonicum, A. calvescens = A. montanum, A. microphyllum = A. venosum, Breynia stipitata var. formosana and B. jormosana = B. vitis-idaea, Glochidion zeylanicum var. tomentosum = G. hirsutum, G. rubidulum = G. thomsonii, G. acuminatum = G. triandrum, G. fagifolium and Phyllanthus fagifolius = Glochidion sphaerogynum, Bridelia penangiena = B. insulana, B. henryana = B. tomentosa. All the types are kept in SCBl and PE.     

Phylogenetic revision of the Taenogera Kröber genus-group (Diptera: Therevidae), with descriptions of two new genera

The phylogenetic relationships of the Taenogera genus-group, consisting of nine genera, are examined using cladistic methods. Twenty-one species representing nine genera and one outgroup were compared in a cladistic analysis across 99 states in 44 characters. The genus Taenogera Kröber is revised to contain only T. longa (Schiner), T. nitida (Macquart) and T. notatithorax Mann. Two new genera are described and figured: Actenomeros gen. n., with two species, A. corniculaticaudus sp. n. and A. onyx sp. n.; and Taenogerella gen. n., with four species, Ta. elizabethae sp. n., Ta. platina sp. n., Ta. schlingeri sp. n. and Ta . nigrapicalis (Mann) comb. n. Phylogenetic analysis also supports the removal of Nanexila gracilis (Mann) comb. n. from Taenogera .     

Relationships between host blood factors and proteases in Glossina morsitans subspecies infected with Trypanosoma congolense

Abstract. Host blood effects on Trypanosoma congolense establishment in Glossina morsitans morsitans and Glossina morsitans centralis were investigated using goat, rabbit, cow and rhinoceros blood. Meals containing goat erythrocytes facilitated infection in G. m. morsitans , whereas meals containing goat plasma facilitated infection in G. m. centralis. Goat blood effects were not observed in the presence of complementary rabbit blood components. N-acetyl-glucosamine (a midguMectin inhibitor) increased infection rates in some, but not all, blood manipulations. Cholesterol increased infection rates in G. m. centralis only. Both compounds together added to cow blood produced superinfection in G. m. centralis , but not in G. m. morsitans. Midgut protease levels did not differ 6 days post-infection in flies maintaining infections versus flies clearing infections. Protease levels were weakly correlated with patterns of infection, but only in G. m. morsitans. These results suggest that physiological mechanisms responsible for variation in infection rates are only superficially similar in these closely-related tsetse.     

Selection of Verticillium lecanii Isolates with High Potential for Biocontrol of Cucumber Powdery Mildew by Means of Components Analysis at Different Humidity Regimes

To identify characteristics for the selection of Verticillium lecanii isolates with high potential for biocontrol of Sphaerotheca fuliginea under glasshouse conditions, an exploratory study was performed on the effect of water limitation on the development of 14 isolates. The conidial germination, growth and sporulation of isolates of V. lecanii were studied in a tritrophic system on cucumber leaves and in a ditrophic system in Petri dishes. Their mycoparasitic ability was studied in S. fuliginea and Cladosporium cladosporioides . All characteristics were clearly affected by humidity. Four isolates showed good biocontrol potential. The performance of isolates on agar had less predictive value than on powdery mildew. The germination of isolates of V. lecanii was lower and the mycelial growth faster on agar than on mildewed leaves under corresponding humidity conditions. The results suggest that conditions in the phyllosphere differed from the set humidity in the surrounding air. A correlation was found between the lysis of C. cladosporioides growing in dual culture on agar with isolates of V. lecanii and the parasitism of powdery mildew on detached, rooted leaves. C. cladosporioides might offer a suitable substrate for testing isolates of V. lecanii for mycoparasitic potential under various environmental conditions. Conidial germination, growth and sporulation had limited predictive value.     

Evaluation of the Palaearctic Eurithia consobrina (Diptera: Tachinidae) as a Potential Biocontrol Agent for Mamestra configurata (Lepidoptera: Noctuidae) in Canada

The evaluation of Eurithia consobrina (Meigen) as a candidate for introduction against bertha armyworm, Mamestra configurata (Walker) (Lepidoptera: Noctuidae), in western Canada included studies of its host range, distribution, synchronization with host, constancy, abundance and life history in Europe. In addition, its diapause induction and its coldhardiness were compared with those of the target host M. configurata and its native tachinid parasitoid, Athrycia cinerea (Coq.). E. consobrina was found to fit criteria for a successful biocontrol agent reasonably well. It also had the potential to fill a largely unoccupied niche in the parasitoid complex of M. configurata. E. consobrina has a facultative diapause of the long-day type, similar to A. cinerea, but is less sensitive to diapause-inducing conditions. E. consobrina is at least as coldhardy as A. cinerea and more coldhardy than M. configurata. Laboratory exposures to temperatures of 0 C for 140 days apparently selected for greater coldhardiness, and later generations survived exposures of 140 days at -15 C without significant mortality. Adult E. consobrina were released at three locations in Manitoba in 1986 and 1987, but establishment has not been confirmed.     

Predation by Halmus chalybeus (Coleoptera: Coccinellidae) on Ceroplastes destructor and C. sinensis (Hemiptera: Coccidae: Ceroplastinae) Infesting Citrus in Northland, New Zealand

Predation by Halmus chalybeus (steelblue ladybird) on two species of wax scale was studied on citrus orchards in Northland, New Zealand. Field experiments using an exclusion technique of enclosing citrus branches in bags, found that larval and adult H. chalybeus preyed on first and second instars of both Ceroplastes destructor (white wax scale) and C. sinensis (Chinese wax scale), but not third instar C. destructor. Third instar C. sinensis and adults of both species were not tested but are rarely, if ever, attacked by H. chalybeus. The sampling of scale and ladybird populations and field experiments showed that few scales of either species survived past the second instar stage where H. chalybeus was numerous. The feeding rate of H. chalybeus on settled first and second instar scales was estimated inside bagged branches. Adults consumed on average 15.6 C. destructor and 13.3 C. sinensis per day per ladybird, while larvae ate 9.7 C. destructor per day. These feeding rates accounted for the experimental reduction of scale populations. H. chalybeus is a useful natural enemy for the control of C. destructor and C. sinensis when its activity is not disrupted by pesticides.     

Further flavonoid studies onAttalea species and some related cocosoid palms

In a flavonoid survey of direct and hydrolysed leaf extracts of sixteenAttalea, sevenScheelea and fourOrbignya species free tricin, tricin 7-glycosides, tricin 5-glucoside and flavone C-glycosides were the most frequent constituents; present in 100, 89, 70, and 81% of species, respectively. Luteolin, quercetin and isorhamnetin were each found in only 15% of the sample. The present results confirm the findings of a previous survey thatAttalea, Scheelea andOrbignya are chemically heterogeneous with as much variation between species as between genera. Furthermore, threeAttalea species,A. allenii, A. guaranitica andA. victoriana showed some infraspecific variation. On the other hand all three accessions ofA. ferruginea and six ofA. geraensis examined gave identical flavonoid profiles. The results support the view thatA. geraensis andA. guaranitica are closely related but do not support the suggested close relationship based on morphology betweenA. oleifera, A. burretiana andA. piassabossu.     

Investigations into the evolutionary history of the polyploid complexAntennaria neodioica (Asteraceae: Inuleae)

TheAntennaria neodioica polyploid agamic complex is a polymorphic species occurring across North America mainly north of the terminal margin of the Wisconsin glacier. This taxonomically difficult group has recently been treated as consisting of the four subspeciesA. neodioica subsp.canadensis, subsp.howellii, subsp.neodioica, and subsp.petaloidea. TheA. neodioica agamic complex has been considered of hybrid origin with several sexual diploid species constituting its parentage. Crosses were made among five sexual diploid species ofAntennaria, morphologically similar toA. neodioica s.l., in an attempt to discover its origins. Representative specimens of the five diploid species,A. neodioica s. l., and the synthetic interspecific F₁ hybrids were subjected to various analyses including PCA, cluster (UPGMA), and discriminant analyses. Results suggest that theA. neodioica complex is of multiple hybrid origin involving the four diploid speciesA. neglecta, A. plantaginifolia, A. racemosa, andA. virginica. BecauseA. neodioica is the result of diverse origin it is more desirable to consider the agamic complex as a separate, distinct species from its sexual diploid relatives. Several morphological characters in the diploid species were determined to be polygenically inherited.Investigations into the Evolutionary History of the Polyploid Complexes inAntennaria (Asteraceae: Inuleae). I.