基于芽苗砧嫁接油茶砧穗创伤后内源激素动态变化分析

为研究油茶(Camellia oleifera A)嫁接时穗条和砧木创伤后内源激素动态变化规律,解析影响砧穗嫁接面愈合的生理机制,为油茶砧穗愈合生长机理提供理论支持。以树龄6年的长林18号和53号的穗条和实生砧木为材料,按照芽苗砧嫁接方法切割穗条S0(0 min)、S10(10 min)、S40(40 min)和砧木茎段Z0(0 min)、Z10(10 min)后,利用液质联用法(HPLC-MS)测定吲哚乙酸(IAA)、脱落酸(ABA)、反式玉米素(TZR)、玉米素(Zeatin)、水杨酸(SA)和茉莉酸(JA)含量,分析不同时间段内源激素变化及品种间差异的关系。结果显示:创伤后18号的TZR、Zeatin和SA含量总体高于53号;18号IAA、SA和JA逐渐下降;TZR和Zeatin分别在S10和S0达最高值后下降;ABA在S10达最高值。53号IAA和JA爱S10达最高值后下降;TZR、Zeatin和SA在S10达低值后逐渐上升;ABA在S0达高值后逐渐下降。砧木茎段创伤前后激素含量除JA外18号高于53号;两品种Z0时激素含量下降,Z10后上升,仅53号ABA和SA含量在Z0达高值后下降。砧木茎段和根部激素含量在品种间除JA外18号高于53号,茎段的IAA、ABA高于根部,其他激素为根部高于茎段。激素比值在品种间和部位间差异明显;IAA/ABA、IAA/TZR、IAA/Zeatin和IAA/JA、ABA/TZR、ABA/Zeatin和ABA/JA比值为53号高于18号;穗条内SA/IAA为18号高于53号,SA/JA和SA/ABA为53号高于18号;砧木茎段均为18号高于53号;TZR/SA、TZR/JA比值在穗条和砧木茎段为18号高于53号。两品种创伤后IAA与JA极显著正相关,而IAA与SA,SA与JA在18号极显著正相关,53号极显著或显著负相关;53号TZR、Zeatin、SA间极显著或显著正相关,JA与TZR、Zeatin和SA极显著负相关。砧木茎段创伤后18号激素间为极显著或显著正相关;53号TZR和Zeatin与IAA、JA极显著正相关,与SA存在显著负相关,SA与JA有显著负相关。砧木茎段和根部间品种间仅在SA与各激素间相关性存在差异,其他激素间存在极显著正相关或负相关。综上所述,砧穗创伤后激素水平上18号在创伤面易于愈伤组织发育,而53号抗逆激素水平较高且与细胞分裂增殖类激素负相关,可能影响53号嫁接后愈合生长;嫁接应在创伤后10 min内较为适宜;砧穗间激素含量及比值的差异可能会影响后期嫁接部位形态重建以及穗条生长。     

Accumulation of elements in the arteries and cardiac valves of Thai with aging

To elucidate whether the extent of element accumulation in the arteries and cardiac valves with aging was different between different races, the authors investigated the accumulation of elements in the arteries and cardiac valves of the Thai with aging and the relationships among elements in the cardiac valves. After ordinary dissection at Chiang Mai University was finished, 16 arteries and 4 cardiac valves were resected and element contents were determined by inductively coupled plasma-atomic emission spectrometry. In the 16 arteries, the average content of calcium was the highest in the site of the abdominal aorta ramifying into the common iliac arteries, and it decreased in the order internal iliac, coronary, abdominal aorta, common iliac, external iliac, superior mesenteric, inferior mesenteric, thoracic aorta, brachial, radial, common carotid, subclavian, ulnar, axillary, renal, and internal thoracic arteries. The average contents of phosphorus and magnesium in respective arteries were parallel with the average contents of calcium, except for the coronary artery. In comparison with the arteries of the Japanese, the trend of calcium accumulation in the arteries of the Thai was almost similar to that in the arteries of the Japanese, except for the coronary artery and thoracic aorta. The calcium accumulation in the coronary artery was much higher in the Thai than in the Japanese, whereas that in the thoracic aorta was lower in the Thai than in the Japanese. Regarding elements in the cardiac valves, the calcium content increased remarkably in the seventies in the aortic valve and in the nineties in the pulmonary valve, but it hardly increased in both the mitral and tricuspid valves with aging. The average content of calcium was the highest in the aortic valve, and it decreased in the order pulmonary, tricuspid, and mitral valves. Regarding the relationship among elements in the aortic valves, it was found that there were extremely significant direct correlations among the contents of calcium, phosphorus, and magnesium, whereas there were significant direct correlations between zinc and either calcium or phosphorus contents. Although significant correlations were found between sulfur and the other element contents in the aortic valves of the Japanese, no significant correlations were found between them in the aortic valves of the Thai. In the mitral valves, extremely or very significant direct correlations were found among the contents of calcium, phosphorus, magnesium, and sulfur, with some exceptions that there were no significant correlations between phosphorus and either magnesium or sulfur contents. In addition, no significant correlation was found in the calcium content between the aortic valve and coronary artery in the same individuals.     

Dynamics of growth and the content of endogenous phytohormones during kidney bean scoto-and photomorphogenesis

The dynamics of growth and the contents of free and bound endogenous IAA, gibberellins (GA), cytokinins (zeatin and its riboside), and ABA in kidney bean plants (Phaseolus vulgaris L., cv. Belozernaya) grown in darkness or in the light was studied. Phytohormones were quantified in 5–15-day-old plants by the ELISA technique. Plant growth and phytohormone content were shown to depend on plant age and the conditions of illumination. During scotomorphogenesis, changes in the biomass and hypocotyl length were highly correlated with the content of GA, whereas during photomorphogeneses, these parameters were correlated with the content of zeatin. In darkness, epicotyl growth displayed a positive correlation with the content of GA, whereas in the light, the correlation was negative. Growth characteristics of the primary leaves were shown to correlate with IAA in darkness and with GA and zeatin in the light. At a low concentration of cytokinins in illuminated leaves, cell divisions occurred, whereas, at the higher cytokinin concentrations, cell expansion occurred. The highest content of GA was characteristic of leaves in the period of growth cessation. ABA accumulated during active leaf and root elongation and biomass increment in the light and during hypocotyl growth in darkness. After plant illumination, the ratio of auxins to cytokinins increased in bean roots and decreased in their epicotyls. Thus, light changed the developmental programs of bean plants, which was manifested in the changed rate and duration of growth of various organs (root, hypocotyl, epicotyl, and leaf). Some mechanisms of light action depended on the contents of IAA, ABA, GA, and cytokinins and the ratios between these phytohormones. Differences between scotonorphogenesis of mono-and dicotyledonous plants are discussed in relation to the levels of phytohormones in them.     

Circadian rhythmic changes in the lipid composition of muscles in kilka <Emphasis Type="Italic">Clupeonella cultriventris</Emphasis> (Clupeidae,clupeiformes) during natural periodicity of feeding in the feeding and spawning periods in the Rybinsk Reservoir

According to data of observations in 2002–2004, differences in the pattern of diurnal fluctuations in the total content and fractional composition of lipids in muscles of mature specimens of kilka Clupeonella cultriventris from the Rybinsk Reservoir in the feeding and spawning periods were revealed. It was established that the feeding intensity in kilka considerably changes throughout 24 h in both periods of the annual cycle, while diurnal fluctuations in the fatness of muscles are distinctly manifested only in the reproductive period and have a dissimilar pattern in specimens of different sexes. In females and males, they are determined mainly by the change in the content of the fraction of reserve lipids-triacylglycerols, as a rule, by its increase in the light hours of the day, several hours after an increase in the feeding activity of fish. The pattern of diurnal fluctuations of the level of lipid fractions (phospholipids, triacylglycerols, cholesterol, and its ethers) in kilka’s muscles differs from that in the feeding period. Possible causes of the change of diurnal variations of the considered indices of lipid metabolism in kilka at an increase in the endocrine activity of its body in the reproductive period is discussed.     

Dichloroacetate- and trichloroacetate-induced phagocytic activation and production of oxidative stress in the hepatic tissues of mice after acute exposure

Dichoroacetate (DCA) and trichloroacetate (TCA) are by-products formed during chlorination of the drinking water and were found to be hepatotoxic and hepatocarcinogenic in rodents. In this study, the abilities of the compounds to induce oxidative stress and phagocytic activation have been studied in B6C3F1 mice. Groups of mice were administered 300 mg/kg of either DCA or TCA, p.o, and were sacrificed after 6 or 12 h. Peritoneal lavage cells (PLCs) were isolated and assayed for superoxide anion (SA) production, and hepatic tissues were assayed for the production of SA, lipid peroxidation (LP), and DNA-single strand breaks (SSBs). TCA resulted in significant production of SA in the PLCs, and in the production of SA, LP, and DNA-SSBs in the hepatic tissues, 12 h after dosing, as compared with the control. DCA administration, on the other hand, resulted in significant increases in the productions of LP and DNA-SSBs in the hepatic tissues at both time points, and in SA production in PLCs and hepatic tissues, 6 h after dosing. However, DCA-induced increases in SA production in PLC and hepatic tissues declined at the 12-h time point, reaching control level in the hepatic tissues. These results may implicate the contribution of phagocytic activation to the induction of oxidative stress in the hepatic tissues and also the role of SA production in the induction of LP and/or DNA damage in those tissues, in response to the compounds. The results also suggest studying the involvement of these mechanisms in the long-term hepatotoxicity/hepatocarcinogencity of the compounds.     

Changes in the Subcellular Distribution of Free Amino Acids in Relation to Light Conditions in Cells of Chara corallina

Subcellular concentrations of free amino acids in internodal cells of a Characeae, Chara corallina, were measured in the dark and in the light. Using an intracellular perfusion technique, we measured concentrations of amino acids in the vacuole, in the flowing sol endoplasm and in the cortical gel layer. The sol endoplasm was predominantly the cytosol. On the basis of microscopic observations, the gel layer appeared to be occupied predominantly by a layer of chloroplasts, while the sol endoplasm was free from chloroplasts. Both in the light and in darkness, the major amino acids in the internodal cells were isoasparagine, glutamic acid, aspartic acid, serine, glycine and alanine, as reported by Sakano and Tazawa (1984). The same major amino acids are found in each of the three compartments. The pattern of distribution of amino acids in the vacuole was similar to that in the sol endoplasm, but quite different from that in the gel layer. The total level of amino acids in the light was lower than that in darkness. The amino acid composition did not change very much, but the subcellular distribution of amino acids differed significantly between cells subjected to illumination and those kept in the dark. Concentrations of amino acids in both the vacuole and the gel layer decreased, whereas those in the sol endoplasm were almost constant.     

The invasion of an introduced predator,Nile perch (<Emphasis Type="Italic">Lates niloticus</Emphasis>, L.) in Lake Victoria (East Africa): chronology and causes

Nile perch, a large predatory fish, was introduced into Lake Victoria in 1954. The upsurge of Nile perch in Lake Victoria was first observed in the Nyanza Gulf, Kenya, in 1979. In Ugandan waters this occurred 2–3 years later and in the Tanzanian Mwanza Gulf 4–5 years later. At the beginning of the upsurge in the Mwanza Gulf in 1983/1984 only sub-adult and adult fishes were found. The first juveniles appeared in 1985, suggesting that the initial increase of Nile perch was mainly caused by migration of sub-adults and adults. Shortly after the onset of trawl fishery in the area in 1973, haplochromines in the Mwanza Gulf started to decline. The final disappearance of the haplochromines, in 1987, only occurred after the Nile perch boom, and despite the abandoning of the haplochromine fishery in 1986. We hypothesize that the decline of haplochromines decreased predation on and competition with juvenile Nile perch and then facilitated survival of these juveniles. Consequently the immigration of sub-adult and adult Nile perch in an area may have paved the way for successful recruitment. Over-exploitation of haplochromine cichlids in the 1970s in the Nyanza Gulf, where the Nile perch upsurge was first observed, may have played a similar role.     

The<Emphasis Type="Italic">Vibrio fischeri sapABCDF</Emphasis> locus is required for normal growth,both in culture and in symbiosis

Inactivation of the sapABCDF genes results in a loss of virulence in several bacterial pathogens of animals and plants. The role of this locus in the growth physiology of Vibrio fischeri, and in the symbiotic colonization of the squid Euprymna scolopes was investigated. In rich medium, a V. fischeri sapA insertion mutant grew at only 85% the rate of its wild-type parent. While a similar effect has been attributed to a potassium-transport defect in sap mutants of enteric bacteria, the V. fischeri mutant grew more slowly regardless of the potassium concentration of the medium. Similarly, the growth-rate defect was independent of the source of either carbon, nitrogen, or phosphorous, indicating that the V. fischeri sap genes do not encode functions required for the transport of a specific form of any of these nutrients. Finally, while a delay in colonizing the nascent light organ of the squid could be accounted for by the lower growth rate of the mutant, a small but statistically significant reduction in its final population size in the host, but not in medium, suggests that the sap genes play another role in the symbiosis. All of these phenotypic defects could be genetically complemented in trans by the sapABCDF genes, but not by the sapA gene alone, indicating that the insertion in sapA is polar to the four downstream genes in the locus. Thus, while the sap locus is important to the normal growth of V. fischeri, it plays different physiological roles in growth and tissue colonization than it does in enteric pathogens.     

啮齿动物作用下退耕地山杏种子扩散与贮藏的季节变化

啮齿动物对植物种子的取食和扩散影响种子的时空分布,继而影响种子的萌发和幼苗建成,因而在森林更新中起着重要作用.在国有济源市愚公林场,选择退耕地生境,于春季、夏季、秋季分别释放人工标记的山杏种子,观察啮齿动物扩散与埋藏山杏种子的季节性差异.结果表明：1）退耕地中的啮齿动物主要包括大林姬鼠、社鼠、黑线姬鼠;2）山杏种子扩散速率在春季显著慢于夏季,夏季显著慢于秋季;3）种子搬运量受季节和种子状态交互作用影响,春季显著少于夏季,夏季显著少于秋季;4）不同季节种子平均搬运距离不同,秋季不同状态种子的搬运距离均大于春季和夏季;5）啮齿动物对山杏种子的贮藏点大小多为1粒种子,少量为2、3粒种子,且贮藏点大小与季节间存在显著的交互作用,春季单粒种子的贮藏点数量显著少于夏季和秋季,而夏季与秋季的贮藏点则倾向于多粒种子;6）在夏季和秋季各有5枚（共释放1800枚）被啮齿动物分散贮藏的山杏种子建成幼苗.     

Comparison of nitrification rates in three branches of the lower river Rhine

The nitrogen cycle in the lower river Rhine was analysed, using data on concentrations of ammonium, nitrite and nitrate, measured in the period from 1972 to 1986. The massive discharge of ammonium in densely populated areas in the Federal Republic of Germany led to microbial nitrification, detectable as decreases in ammonium and nitrite concentrations in the lower river Rhine over reaches 85–133 km long. The distribution of the nitrogen-rich Rhine waters over three different branches in the Netherlands permits some of the factors governing microbial nitrification in the river bed to be discriminated. In the fast-flowing main channel, intensively used by ships, nitrification is more important than in the smaller branches, despite the short residence time of the water in the main channel. Differences in the flow rate of water, in grain size distribution of sediments, and in intensity of shipping (aeration, turbulence) seemed to be responsible for the different rates of nitrification.     

Distribution and Abundance of Primates in Rain Forests of the Western Ghats,Karnataka, India and the Conservation of Macaca silenus

We assessed the distribution and abundance of 4 species of diurnal primates viz. lion-tailed macaque, bonnet macaque, Nilgiri langur and Hanuman langur, in 2 areas—Brahmagiri-Makut and Sirsi-Honnavara—in rain forests of the Western Ghats in the state of Karnataka, India. The Nilgiri langurs in Brahmagiri-Makut and the lion-tailed macaques in Sirsi-Honnavara are the northernmost populations of the 2 species in the Western Ghats. The 2 regions represent changes in ecological zones in the Western Ghats. In Brahmagiri-Makut, Hanuman langurs and bonnet macaques occupy lower elevations whereas Nilgiri langurs live in relatively higher altitudes. Only one group of lion-tailed macaques was in Brahmagiri-Makut. In the forests of Sirsi-Honnavara, 3 species of primates viz. lion-tailed macaque, bonnet macaque and Hanuman langur were in larger numbers throughout the forest. A self-sustainable single population of 32 groups of lion-tailed macaques occurred in Sirsi-Honnavara. Few subspecies of Hanuman langurs exist in the study regions. Due to local hunting practices, the relative abundance of primates in Brahmagiri-Makut is lower than that in Sirsi-Honnavara.     

Structure, distribution and physiological functions of ghrelin in fish

Ghrelin was originally purified and characterized in rats and humans as the first identified endogenous ligand of the growth hormone secretagogue receptor. In mammals, ghrelin is mainly produced in the stomach, with minor levels of ghrelin present in the brain and various other tissues. Ghrelin is involved in the regulation of many physiological functions including the regulation of growth hormone secretion and food intake in mammals. The gene and peptide structures of ghrelin have been recently identified in several fish species. As in mammals, ghrelin mRNA is mainly expressed in the gut of fish. Ghrelin is involved in the regulation of a number of physiological functions, including the regulation of pituitary hormone release and the stimulation of food intake in fish. In this review, we wish to provide an up-to-date discussion on the structure, distribution and functions of ghrelin in fish, in comparison to ghrelin in other vertebrates.     

Identification of reciprocally regulated gene modules in regenerating dorsal root ganglion neurons and activated peripheral or central nervous system glia

Differential gene expression in the rat after injury of dorsal root ganglion neurons in vivo, and simulation injury of Schwann cells and oligodendrocytes in vitro was analyzed using high-density cDNA microarrays. The analyses were carried out to study the genetic basis of peripheral nerve regeneration, and to compare gene regulation in glia of the central (oligodendrocyte) and peripheral (Schwann cell) nervous systems. The genes showing significant differential regulation in the three study groups represented all aspects of cellular metabolism. However, two unexpected observations were made. Firstly, a number of identical genes were differentially regulated in activated Schwann cells, activated oligodendrocytes and regenerating DRG neurons. Specifically, a group of 113 out of 210 genes that were down-regulated in Schwann cells upon lipopolysaccharide (LPS) treatment, were identical to genes up-regulated in the injured, regenerating DRG. Furthermore, a group of 53 out of 71 genes that were down-regulated in interferon gamma (IFN-gamma)/LPS-activated oligodendrocytes, were identical to genes up-regulated in the DRG neurons. Finally, 22 genes were common to these three groups, i.e., down-regulated in activated oligodendrocytes, down-regulated in activated Schwann cells, and up-regulated in regenerating DRG neurons. Secondly, a group of 16 cell-cycle and proliferation-related genes were up-regulated in the DRG following sciatic nerve crush, despite the absence of cells undergoing mitosis in the DRG, or any significant presence of apoptosis-related gene expression. Therefore, it appears that in these three cell types, large sets of genes are reciprocally regulated upon injury and/or activation. This suggests that the activation of the injury-related gene expression program in cell derivatives of the neuroectoderm involves, in part, highly conserved genetic elements.     

Age-dependent Increases of Calcium, Phosphorus, and Sodium in the Uterine Arteries of Thai

To elucidate compositional changes of the uterine artery with aging, the authors investigated age-related changes of elements in the uterine arteries of Thai. After ordinary dissection by medical students at Chiang Mai University was finished, the uterine arteries were resected from Thai subjects. Thai subjects ranged in age from 27 to 86 years (average age = 63.3 +/- 17.7 years). The element content of the uterine arteries was analyzed by inductively coupled plasma-atomic emission spectrometry. It was found that the Ca, P, and Na contents increased progressively in the uterine arteries of Thai with aging. A significant accumulation of Ca and P in the uterine arteries of Thai was found in the sixties patients, and the accumulation increased markedly in the seventies. Regarding the uterine arteries in subjects more than 60 years, the extent of accumulation of Ca and P in the uterine arteries of Thai was one half of that in the uterine arteries of Japanese. Regarding the relationships among elements, extremely significant direct correlations were found among the contents of Ca, P, Mg, Zn, and Na in the uterine arteries of Thai. As Ca increased in the uterine arteries of Thai, P, Mg, Zn, and Na increased simultaneously in the arteries.     

Mycorrhizae and their potential use in the agricultural and forestry industries

Mycorrhizal fungi associated with plant roots increase the absorption of nutrients, particularly phosphorus, and thus enhance the growth of crop plants and trees. Vesicular-arbuscular mycorrhizae (VAM) occur in approximately 90% of all vascular plants including most of the important agricultural species, whereas ectomycorrhizae are found in most of the economically important tree species of the temperate regions of the world, and in some tropical trees. These symbiotic associations are, therefore, important in crop and biomass production. For this reason they are receiving considerable attention in agriculture and forestry. Currently, VAM are utilized in fumigated soils, greenhouse crops, and in the reclamation of disturbed sites. Ectomycorrhizae are employed in the establishment of trees in nurseries, in reforestation programs, and in the production of containerized seedlings. Production of VAM and ectomycorrhiza inoculum for large scale projects is now feasible but many basic questions related to persistence of these fungi in field situations, competition with other microorganisms, and particularly the most efficient fungi to use for particular hosts remain largely unanswered.     

Comparison of dietary and waterborne exposure to benzo a pyrene: bioavailability,tissue disposition and CYP1A1 induction in rainbow trout Oncorhynchus mykiss

Absorption and tissue distribution of benzo\[ a ]pyrene (BaP)-derived radioactivity were studied in juvenile rainbow trout following dietary or waterborne exposure. In order to compare the bioavailability of BaP, the fish were exposed to 1.5 mCi 3H-BaP kg-1 fish, either in the diet or in the water as a 2 days static exposure. Furthermore, tissue levels of BaP-derived radioactivity bound to macromolecules in different tissues were studied in non-induced fish, and in fish induced by additional treatment with unlabelled BaP (corresponding to 5 mg kg-1 fish) in the water. Absorption and tissue distribution of 3H BaP were studied by liquid scintillation counting and whole-body autoradiography. BaPderived radioactivity bound to macromolecules in different tissues was studied by autoradiography of solvent-extracted whole-body sections. The hepatic CYP1A induction was measured as EROD activity. Exposure to unlabelled BaP resulted in a marked induction of hepatic EROD activity in rainbow trout 2 days after the start of the exposure. Significant higher concentrations of radiolabelled compound were observed in waterborne-exposed fish, in contrast to dietary-exposed fish. High concentrations of radiolabelling were observed in the gills, liver, bile, intestines, olfactory organ, kidney and the skin of the waterborne-exposed fish. In the dietary-exposed fish, high levels of radioactivity were observed in the intestines and the bile, whereas lower concentrations were present in the liver. Only traces of radioactive compound were observed in the gills. In contrast to waterborne-exposed fish, no radioactivity was detected in the olfactory organ or skin. In autoradiograms of sections extracted with a series of polar and non-polar solvents, a large fraction of radioactivity was still present in the gills, olfactory organ, liver, kidney, skin and intestinal mucosa of the waterborne-exposed fish, indicating that reactive BaP intermediates formed by CYP1A-mediated metabolism were bound to macromolecules in these tissues.     

Neuropeptides in the gastrointestinal canal of Necturus maculosus

Summary The presence and distribution of regulatory peptides in nerves and endocrine cells of the stomach, intestine and rectum of a urodele amphibian, the mudpuppy, Necturus maculosus, was studied immunohistochemically in sections or whole-mount preparations of the gut wall. The effect of the occurring peptides on gut motility was studied in isolated strip preparations of circular and longitudinal smooth muscle from different parts of the gut.Bombesin-, neurotensin-, substance P- and VIP-like immunoreactivity was present in abundant nerve fibres in the myenteric plexus of both stomach, intestine and rectum. Single fibres or bundles were present in the circular muscle layer and in a well-developed deep muscular plexus in the intestine and rectum. Immunoreactive nerve cells were found in the myenteric plexus of the stomach, intestine (neurotensin only) and rectum. Gastrin/CCK-like immunoreactivity was observed only in a few fibres in stomach and rectum.Endocrine cells containing bombesin-, met-enkephalin-, gastrin/CCK-, neurotensin-, somatostatin- or substance P- like immunoreactivity were present in the mucosa.The effect of bombesin was an inhibition of the rhythmic activity in circular muscle preparations and in longitudinal muscle from the rectum, while longitudinal muscle from the stomach usually responded with a weak increase in tonus. Neurotensin, like bombesin, was inhibitory on the spontaneous rhythmic activity of circular muscle throughout the gut, while the effect on longitudinal muscle was an increase in tonus. Met-enkephalin and substance P increased the tonus of all types of preparations, and often, in addition, initiated a rhythmic activity superimposed on this maintained tonus. VIP had a general inhibitory effect on the preparations, decreasing tonus and/or abolishing rhythmic activity.It is concluded that bombesin-, neurotensin-, substance P- and VIP-like peptides are present in nerves throughout the urodele gut and may have physiological functions in regulating the motility of the gut. The gastrin/CCK-like peptide present in nerves of the stomach and rectum may affect the function of these parts of the gut. The regulatory peptides present in endocrine cells may, perhaps with the exception of the somatostatin-like peptide, affect the motility humorally.     

Aminopeptidase N during the ontogeny of the chick

Little is known about the production and function of metallopeptidases in embryonic development. One such enzyme, aminopeptidase N (APN), is present in several epithelia, the brain and angiogenic vessels in adults. APN promotes vascular growth and endothelial cell proliferation in physiological and pathological models of angiogenesis. However, its possible role in embryonic angiogenesis or other developmental processes is unknown. Its expression profile in the early phase of embryonic development has not been reported. We report here the expression of this enzyme during the early development of the chick embryo, using complementary techniques for monitoring APN mRNA, protein, and enzymatic activity. We detected APN in the embryo as early as gastrulation. In addition to the known sites of APN production identified in both adults and rat fetuses toward the end of gestation, APN was found in unexpected sites, such as the primitive streak, the dorsal folds of the neural tube, the somites, and the primordia of several organs. APN was present mostly in the cardiovascular compartment during the first 13 days of incubation, and in the hematopoietic compartment (yolk sac and aorta-gonad-mesonephros region) early in development. This study provides clues as to the possible role of APN in embryonic development.