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1.
The effect of phorbol myristate acetate (PMA) on the hormonal responsiveness of hepatocytes from lean and obese Zucker rats was studied. Phenylephrine-stimulated phosphatydylinositol labeling and phosphorylase activation were antagonized by PMA in cells from obese and lean animals; bigger residual effects were observed in cells from obese animals even at high PMA concentrations. Cyclic AMP accumulation induced by isoproterenol, glucagon, forskolin and cholera toxin was higher in cells from lean animals than in those from obese rats. PMA diminished glucagon- and cholera toxin-induced cyclic AMP accumulation; cells from lean animals were more sensitive to PMA. Two groups of isoforms of protein kinase C (PKC) were observed in hepatocytes from Zucker rats using DEAE-cellulose column chromatography: PKC 1 and PKC 2. The PKC 1 isozymes were separated into four peaks using hydroxylapatite: aa, 1a (PKC-beta), 1b (PKC-alpha) and 1c. Short treatment with PMA decreased the activity of PKC 1 (peaks 1b (PKC-alpha) and 1c) and to a lesser extent of PKC 2; cells from lean animals were more sensitive to PMA than those obtained from obese rats. Our results indicate that cells from genetically obese Zucker rats are in general less sensitive to this activator of protein kinase C than those from their lean littermates. The possibility that alterations in the phosphorylation/dephosphorylation cycles, that control metabolism and hormonal responsiveness, may contribute to this obese state is suggested.  相似文献   

2.
Objective: This study examined the effects of topiramate (TPM), a novel neurotherapeutic agent reported to reduce body weight in humans, on the components of energy balance in female Zucker rats. Research Methods and Procedures: A 2 × 3 factorial experiment was performed in which two cohorts of Zucker rats differing in their phenotype (phenotype: lean, Fa/?; obese, fa/fa) were each divided into three groups defined by the dose of TPM administered (dose: TPM 0, vehicle; TPM 15, 15 mg/kg; TPM 60, 60 mg/kg). Results: The reduction in body weight gain induced by TPM in both lean and obese rats reflected a decrease in total body energy gain, which was more evident in obese than in lean rats. Whereas TPM administration did not influence the intake of digestible energy in lean rats, it induced a reduction in food intake in obese animals. In lean, but not in obese rats, apparent energy expenditure (as calculated by the difference between energy intake and energy gain) was higher in rats treated with TPM than in animals administered the vehicle. The low dose of TPM decreased fat gain (with emphasis on subcutaneous fat) without affecting protein gain, whereas the high dose of the drug induced a reduction in both fat and protein gains. The effects of TPM on muscle and fat depot weights were representative of the global effects of TPM on whole body fat and protein gains. The calculated energetic efficiency (energy gain/energy intake) was decreased in both lean and obese rats after TPM treatment. TPM dose independently reduced hyperinsulinemia of obese rats, but it did not alter insulinemia of lean animals. Discussion: The present results provide sound evidence for the ability of TPM to reduce fat and energy gains through reducing energetic efficiency in both lean and obese Zucker rats.  相似文献   

3.
1. The populations of alpha 1- and beta-adrenergic receptors in brown adipose tissue (BAT) of genetically obese Zucker rats (fa/fa) were studied with [3H]prazosin and [3H]CGP-12177 respectively. 2. The density of alpha 1-adrenergic receptors in BAT was significantly lower in obese than in lean Zucker rats, both at 2-4 months of age and at 6 weeks of age. The density of beta-adrenergic receptors was identical in BAT of lean and obese 6-week-old Zucker rats. 3. Cold-acclimation increased the alpha 1-receptor density significantly in BAT of both lean and obese Zucker rats, and the number of beta-receptors was also somewhat increased. 4. Sucrose feeding did not affect the density of alpha 1-receptors in BAT of lean or obese Zucker rats, but it increased beta-receptor density. 5. Adrenalectomy restored the density of alpha 1-adrenergic receptors in BAT of obese Zucker rats to the value observed in lean rats. 6. It is concluded that there is a direct correlation between alpha 1-receptor density and tissue recruitment, and that alpha 1-receptor density is thus positively correlated with sympathetic activity. beta-Receptor density is apparently better correlated with feeding conditions.  相似文献   

4.
Docosahexaenoic acid (DHA) is required for neurotransmitter synthesis and learning. Conversion of α-linolenic acid (ALA) to DHA is considered adequate to support brain function in youth, but it is unknown if brain DHA can be maintained in insulin resistant states. This study investigated brain fatty acid and desaturase activities in young insulin resistant Zucker rats on diets with and without DHA. Male fa/fa and lean rats were fed diets enriched with flaxseed (FXO, ALA: 35.5% fatty acids), menhaden (MO, DHA: 9.2%) or safflower oil (SO, linoleic acid: 54.1%) for 9 weeks, n=8 per diet per genotype. Compared to lean, the 15 week old fa/fa rats were obese (56% heavier) and insulin-resistant (>18-fold in homeostasis model assessment of insulin resistance). The forebrain of fa/fa rats had higher palmitoleic (16:1n-7) and dihomo-γ-linolenic (20:3n-6) acids, and higher Δ9, Δ6 but lower Δ5 (all P≤.006) desaturase indices than lean. The Δ9 and Δ6 desaturase indices positively, while the Δ5 negatively (all P≤.01) correlated with insulin resistance. The Δ9 desaturase index positively correlated with adiposity index. The percentage of forebrain DHA of fa/fa rats was lower (P=.011) than lean rats when fed FXO diet while there was no difference (P>.05) between fa/fa and lean rats fed MO or SO diet. Thus, the alterations in the fatty acid and desaturase indices in the brain were consistent inhibited forebrain synthesis of DHA in the fa/fa rats. ALA may not have potential to effectively serve as a precursor for synthesizing DHA for youth forebrain during insulin resistance since Δ5 desaturase activity is limited.  相似文献   

5.
As an experimental model, we used 6-week-old genetically obese-hypertensive rats (SHR-fe/fa) which were obtained by transferring the fatty/fa gene of hyperlipaemic obese rats into the genome of the SHR strain: the SHR-fa/fa were bigger and more hypertensive than their SHR littermates. Studying the capacitity of the hearts, kidneys, spleens, brains and lungs to synthesize PGE2, PGF2α and TXA2, enabled us to show that
  • •- the hearts and lungs of SHR-fa/fa synthesized more PG than those of SHR
  • •- DHR-fa/fs brains generated less icosanoids than those of SHR
  • •- the amounts of PGE2 and TXA2 produced by the kidneys are similar in SHR and in SHR-fa/fa.
From the experimental data we can infer that the introduction of the fatty/fa gene into the genome of SHR does not significantly alter the capacity of the kidneys to synthesize icosanoids; the more severe hypertension in the SHR-fa/fa would result from an increase in TXA2 biosynthesis by cardiac tissue which, at the same time, synthesized more PGE2, which could be a means of defence against hypertension. Moreover this genetical manipulation inhibited the icosanoid-synthesizing capacity of the brain which thus attenuated the central nervous system activity of the animals.  相似文献   

6.
TYRO3、AXL和MER受体是受体酪氨酸激酶亚家族之一,广泛地表达在哺乳动物神经、免疫、生殖、血液等系统多种细胞中,促进细胞存活、增殖和分化。本研究利用基因芯片技术筛选基因敲除的TYRO3~(~(-/-))AXL~(-/-)MER~(-/-)小鼠骨髓细胞中差异性表达的m RNA,并进行生物信息学分析。与正常小鼠骨髓细胞相比,TYRO3~(-/-)AXL~(-/-)MER~(-/-)小鼠骨髓细胞中差异表达基因探针共1 363条,其中表达上调的基因探针499条、下调的基因探针864条。GO功能富集分析发现上调的基因主要参与免疫反应,下调的基因主要参与造血。KEGG Pathway富集分析发现上调的基因主要参与细胞粘附分子和抗原呈递等信号通路。Real-time PCR验证5个差异基因,与芯片中表达变化趋势一致。因此TYRO3、AXL和MER受体共同参与调控机体的免疫反应和血细胞分化。  相似文献   

7.
The complex trans-PtCl(p-Tol)(SEt2)2 is obtained from the reaction of [Pt(p-Tol)2(SEt2)]2 with PtCl2(SEt2)2 and SEt2 in mole ratio 1:2:2. The mono(p-tolyl)platinum(II) and bis(p-tolyl)platinum(II) complexes of diethylsulfide react with 2,2′-bipyridine to form the complexes PtX(p-Tol)(bpy) (X=p-Tol, Cl) and are useful reagents for organoplatinum chemistry. X-ray crystal structures are presented for square planar PtCl(p-Tol)(bpy) and the centrosymmetric dimer [Pt(p-Tol)2(μ-SEt2)]2.  相似文献   

8.
Reaction of the metalloligand [Pt2(μ-S)2(PPh3)4] with the N-heterocyclic carbene (NHC) complexes IPrAuCl, IMesAuCl and IMesAgCl in methanol gave the first examples of metal adducts of [Pt2(μ-S)2(PPh3)4] that contain NHC ligands, namely [Pt2(μ-S)2(PPh3)4AuL]+ (L = IPr, IMes) and [Pt2(μ-S)2(PPh3)4AgIMes]+. The complexes were isolated as hexafluorophosphate salts. Reaction of [Pt2(μ-S)2(PPh3)4] with excess IPrAuCl in refluxing methanol yielded only the mono-adduct, in contrast to the behaviour with the gold(I) phosphine complex Ph3PAuCl, which undergoes double addition giving [Pt2(μ-SAuPPh3)2(PPh3)4]2+. The X-ray structure of [Pt2(μ-S)2(PPh3)4AuIPr]PF6 was determined and reveals that the ‘free’ sulfide is substantially sterically protected by the IPr ligand, accounting for the low reactivity towards addition of a second AgIPr+ moiety.  相似文献   

9.
Zusammenfassung Gemeinsame Verhaltensmerkmale ganzer Gruppen wurden bis jetzt nur selten zusammengestellt. Die Notwendigkeit einer derartigen zusätzlichen Kennzeichnung für die meisenartigen Vügel ergibt sich aus der Vielfalt der Auffassungen. Vor allem die Stellung der GattungenAegithalos undTichodroma ist unklar und in den wissenschaftlichen Werken uneinheitlich.Es wurde deshalb versucht, die wichtigsten Verhaltensweisen der GattungenParus undAegithalos einerseits darzustellen, andererseits die der GattungSitta gegenüberTichodroma undCerthia. Parus Alle bisher bekannten Arten dieser Gattung zerkleinern Nahrung, indem sie diese mit dem Fuß festhalten und Teile davon abzupfen bzw. die Schale von Samen zertrümmern. Dieses Verfahren beherrschen schon Jungvögel, die noch nicht selbständig Nahrung aufnehmen. Alle Meisen sind Höhlenbrüter; die Methode, Höhlen der verschiedensten Größen mit Moos weitgehend auszufüllen, wird als Anpassung an die Verschiedenartigkeit vorgefundener, meist durch Fäulnis entstandener Baumhöhlen gedeutet. Das Bedecken des unvollständigen Geleges kann Nestfeinde daran hindern, das Gelege beim Einblick in die Baumhöhle zu erkennen, da Meisenhöhlen im allgemeinen infolge der Unförmigkeit des Höhleneinganges nicht völlig dunkel sind. Die Nestlingszeit von rund 20 Tagen stellt wohl sicher eine Anpassung an das Brüten in einer geschützten Höhle dar. Ausführlich wird die Drohkombination besprochen, die bei allen Meisen festzustellen ist, die im Nest gestört werden. Diese Kombination, bestehend aus einem Zischlaut, dem Zuklappen des aufgesperrten Schnabels und gleichzeitigen Schlagen der Flügel an die Höhlenwände, kommt nur in einer Höhle zur vollen Wirkung und ist ein Zeichen dafür, daß Meisen phylogenetisch sehr alte Höhlenbrüter sind. Befiederte Jungmeisen wenden sie ebenso an wie in einer Höhle bedrängte Meisen- . Bei der Balz unterscheiden sich Meisen nicht grundlegend von anderen Passeres. Zum Sammeln von Vorräten sind nicht alle Arten von Meisen befähigt, sondern hauptsächlich solche, die im Winterhalbjahr vorwiegend von Samen leben. Kohl- und Blaumeisen sind möglicherweise nicht von Anbeginn Samenfresser gewesen; sie sammeln keine Vorräte. BeiParus major öffnet eine indische Rasse im Käfig keine Samen.Aegithalos Schwanzmeisen unterscheiden sich von denParus-Arten durch eine starke soziale Bindung an Artgenossen. Außer der Brutzeit trifft man nie einzelne Schwanzmeisen an, während Meisen auch mit anderen Arten vorlieb nehmen. Schwanzmeisen nächtigen stets in gegenseitiger Berührung und die Jungen rufen sich mit einem spezifischen Laut immer wieder zusammen. Schwanzmeisen sind nicht territorial. Mindestens beiAegithalos sowie bei dem amerikanischenPsaltriparus können mehr als zwei Altvögel am Nestbau und der Jungenaufzucht beteiligt sein. Von den Lautäußerungen der Schwanzmeisen hat nur einer eine gewisse Ähnlichkeit mit Meisenrufen, alle anderen sind stark verschieden; dies gilt auch für den Warnruf gegenüber Luftfeinden. Die Nestlingszeit der Schwanzmeisen entspricht der von Freibrütern; sie ist deutlich kürzer als bei Meisen. Am Nestbau beteiligen sich und , während bei denParus-Arten nur das baut.Sitta Während die Fähigkeit, abwärts zu klettern, nicht für alleSitta-Arten gilt, zerkleinern alle bisher bekannten Arten Nahrung, indem sie diese in Spalten stecken und mit dem Kopf nach unten hängend daraufklopfen. Dies ist ein grund-legender Unterschied zu allenParus-Arten. Alle holarktischenSitta-Arten sammeln Vorräte, alle sind Höhlenbrüter, die große Bruthöhlen, ähnlich wie die Meisen, verkleinern. Im Unterschied zu den Meisen fehltSitta ein Drohverhalten bei Störung im Nest. Eine Reihe von Arten schützt jedoch den Nesteingang teils durch eine Mauer aus Lehm, teils durch Beschmieren mit frischem Harz oder dadurch, daß Insekten am Flugloch so verrieben werden, daß ein Insektenduft entsteht. Bei Felsenkleibern sind diese Methoden kombiniert.Tichodroma Neuerdings wird der Mauerläufer eher zu den Kleibern gestellt als zuCerthia. Tatsächlich erinnert nur die Schnabelform an letztere Gattung. Es scheint, daß der Mauerläufer für seine Brut die Nähe von Felsschluchten oder Sturzbächen bevorzugt. Dort waren die Rufe flügger Junger im Nest nicht zu hören. Das auffallende Farbmuster kann eine ökologische Anpassung sein. Bettelnde Jungvögel schlagen die Flügel nach dem Ausfliegen viel höher und auffallender als andere Passeres. In der Lebensweise gleichtTichodroma vielfach dem FelsenkleiberS. neumayer, indem sie zur Brutzeit mehr Geröllfelder und den Rand von Schluchten aufsucht als Steilwände. Höhenunterschiede werden stets mit den Flügeln überwunden. Die auffallende Größe der Flügel läßt sich aus der Funktion leicht erklären. Das periodische Flügelzucken entspricht weitgehend dem vonSitta neumayer, nur mit dem Unterschied, daß es dafür beim Mauerläufer keiner erkennbaren Erregung bedarf. An der Bruthöhle wurde ein einziges Mal eine Pendelbewegung beobachtet, wie sie nur bei Kleibern vorkommt. Die Länge von Brutdauer und Nestlingszeit entspricht vor allem der der Kleiber.Certhia Der Stützschwanz ermöglichtCerthia eine völlig andersartige Klettermethode gegenüberSitta undTichodroma. Baumläufer sind an das Brüten in schmalen Spalten angepaßt. Die Brutdauer liegt zwischen der der Meisen und der Kleiber. Die Jungen sind sehr empfindlich und verlassen das Nest, bevor sie fliegen können, bei der geringsten Störung. Damit weichen sie ebenso von anderen Höhlenbrütern ab wie die brütenden , die gleichfalls sofort das Nest verlassen, wenn sie eine Gefahr wahrnehmen. Wenn das dem den zukünftigen Brutplatz demonstriert, schlüpft es ein und führt nach dem Herauskommen eine ritualisierte Schüttelbewegung aus, die Meisen und Kleibern fehlt. Auch die Schlafgewohnheiten sind verschieden.Es wird vorgeschlagen, die Schwanzmeisen als eigene Familie von den Meisen zu trennen. Den Kleibern gebührt ein eigener Familien-Status. Der Mauerläufer ist keinesfalls mitCerthia nahe verwandt, sondern sollte den Kleibern als Unter-familie zugeteilt werden, sofern er nicht eine eigene Familie darstellt.
Summary Up to the present time general behavioral characteristics of entire groups have rarely been synthesized. The necessity of an additional characterization of this kind for the tit-like birds is revealed in the multiplicity of taxonomic interpretations. The positions of the generaAegithalos andTichodroma are especially unclear and are diversely treated in scientific writings.Therefore it was attempted, on the one hand, to present the most important behavior patterns of the generaParus andAegithalos, and on the other hand, those of the genusSitta contrasted withTichodroma andCerthia. Parus All species of this genus known to date break up food items by holding them with the foot and picking off pieces or breaking off the hulls of seeds. Even young which do not yet feed independently have this behavior. All tits are hole nesters. The procedure of the extensive filling in of cavities of the most varied sizes with moss is explained as an adaptation to the variation in tree cavities encountered, largely as the result of rotting. The covering of an incomplete clutch can prevent predators' recognition of the clutch when looking in the hole, for tit holes are generally not completely dark as a result of the irregularity of the entrance. The nestling period of about twenty days certainly represents an adaptation to nesting in a protected cavity. The threat combination present in all tits when disturbed in the nest is discussed in detail. This combination, consisting of a hissing sound, snapping closed of the open bill and concomitant blows of the wings against the sides of the cavity, is fully elicited only in a cavity, and is an indication that hole nesting appeared quite early in the phylogeny of tits. Feathered young utilize this behavior just as do male tits which are disturbed in a cavity. Tits do not differ basically from other passerines in courtship. Not all species of tits store food; those which do are mainly those which feed predominantly on seeds during the winter. Coal and Blue Tits were perhaps not originally seed eaters; they do not store food. The Indian race ofParus major does not eat seeds in captivity.Aegithalos Long-tailed Tits differ fromParus species in their strong social ties to conspecifics. Lone Long-tailed Tits are never encountered outside of the breeding season, whereas other tits even show a preference for other species. Long-tailed Tits always spend the night in mutual contact and the young are brought together repeatedly with a specific call. They are not territorial. At least inAegithalos and the AmericanPsaltriparus more than two adults can take part in nest building and rearing of the young. Only one of the vocalizations of the Long-tailed Tit has a certain similarity to the calls of other tits; all the others differ markedly, also the warning call against aerial predators. The nesting period of the Long-tailed Tit corresponds to that of open nesters; it is clearly shorter than that of other tits. Both male and female participate in nest building, whereas in theParus species only the female builds.Sitta Whereas the ability to climb downwards does not hold for allSitta species, all species known to date break up food items by putting them in crevices and hammering on them with the head hanging downward. This is a basic difference from allParus species. All Holarctic species ofSitta store food and all are hole nesters which, like the tits, reduce the size of large nesting holes. As opposed to the tits,Sitta lacks a threat display when disturbed in the nest. However, a number of species protect the nest entrance, in part by a mud wall, and partly by smearing fresh resin about, or by rubbing insects around the hole so that an insect odor results. Rock Nuthatches combine these methods.Tichodroma The Wall Creeper has recently been placed closer to the nuthatches than toCerthia. Actually only the form of the bill resembles this genus. It seems that the Wall Creeper prefers the vicinity of rocky ravines or waterfalls for breeding. The calls of fledged young in the nest were not heard. The striking color pattern can be an ecological adaptation. After leaving the nest, begging young beat their wings much more widely and conspicuously than other passerines.Tichodroma bears a strong resemblance to the Rock Nuthatch,S. neumayer, in its way of life, in that for the breeding season it seeks out more boulderstrewn fields and ravine edges than steep cliffs. Vertical movements are always accomplished by flight. The striking size of the wing can be easily explained from its function. The periodic wing flashing corresponds closely to that ofSitta neumayer, and differs in the Wall Creeper only in the fact that no recognizable stimulus is needed for it to occur. A single observation was made of an oscillating movement at the nesting cavity, which only occurs in nuthatches. The length of the incubation and nestling periods corresponds especially well to that of the nuthatches.Certhia The prop-like tail makes possible a completely different method of climbing in contrast toSitta andTichodroma. Tree Creepers are adapted for breeding in narrow crevices. The length of the incubation period is intermediate between that of the tits and that of the nuthatches. The young are easily disturbed and will leave the nest, before they can fly, at the least disturbance. They also differ from other hole nesters in that the female will leave the nest immediately if she perceives danger. When the male shows the female the prospective nesting site he slips in and, after coming out, performs a ritualized shaking movement which is not found in tits and nuthatches. The sleeping habits also differ.It is suggested that the Long-tailed Tits and Bush Tits be separated from the other tits, and placed in a family by themselves. The nuthatches deserve familial status. The Wall Creeper is by no means closely related toCerthia, and ought to be designated a subfamily of the nuthatches, in so much as it does not represent a separate family.


Prof. Dr. Konrad Lorenz zum 60. Geburtstag gewidmet

Da uns nun nach Nestbau, Jugendbedaunung, Sperrachen, Stimme, Bewegungsweise z. B. Baum- und Mauerläufer oder Schwanz- und Waldmeisen untereinander durchaus nicht näher zu stehen scheinen als z. B. Waldmeisen und Kleiber, so begnügen wir uns mit den GattungenO. und M. Heinroth  相似文献   

10.
Pt(II) complexes of the types cis- and trans-Pt(amine)2I2 with amines containing a phenyl group were synthesized and studied mainly by IR and multinuclear (195Pt, 1H and 13C) magnetic resonance spectroscopies. The compounds are not very soluble. In 195Pt NMR spectroscopy, the cis isomers were observed at slightly lower fields than the trans analogues (average Δδ = 11 ppm) in acetone. In 1H NMR, the NH groups were also found at slightly lower fields in the cis isomers. The coupling constants 2J(195Pt-1HN) varied from 53 to 85 Hz and seem slightly smaller in the trans configuration. The 13C NMR spectra of most of the complexes were measured. No coupling constants J(195Pt-13C) were detected due to the low solubility of the compounds. The cis isomers containing a phenyl group on the N atom could not be isolated except for Ph-NH2 which was shown to be a mixture of isomers in acetone. The tetrasubstituted ionic compounds [Pt(amine)4]I2 for the less crowded ligands were also studied mainly by NMR spectroscopy in aqueous solution. The 195Pt chemical shifts vary between −2855 and −2909 ppm. The coupling constants 3J(195Pt-1H) are about 40 Hz. The iodo-bridged dinuclear species I(amine)Pt(μ-I)2Pt(amine)I were also synthesized and characterized. Two isomers are present in acetone solution for most of the compounds. Their δ(Pt) signals were observed at about −4000 ppm and their coupling constants 2J(195Pt-1HN) are around 69 Hz.  相似文献   

11.
锦鸡儿(Caragana sinica(Buchoz) Rehd)传粉生物学研究   总被引:1,自引:0,他引:1  
对唐家河国家自然保护区内锦鸡儿(Caragana sinica(Buchoz)Rehd)的花期、访问者、有效传粉者种类及行为、花蜜分泌节律和繁育系统等进行定点观察和实验处理。结果表明:锦鸡儿单花花期约5d,种群花期约20d。拥有以吸蜜为主的条蜂属(Anthophora)、熊蜂属(Bombus)和太阳鸟属(Aethopyga)3种传粉者功能群。综合访花频率和花粉落置数,茜条蜂(Pyganthophora rubricus Dours)和蓝喉太阳鸟(Aethopyga gouldiae)为主要有效传粉者,熊蜂(Bombus)为次要有效传粉者;蚂蚁(formicidae)和西方蜜蜂(Apis mellifera Linnaeus)为主要盗蜜者。套袋处理结果表明,花蜜分泌日变化中,最大花蜜量发生在16:00左右;花蜜随单花花期变化中,花蜜体积最大发生于单花第5天;分泌均呈递增趋势。花蜜分泌节律与访花频率呈正相关。繁育系统检测显示,花粉胚珠比为3779±320.92,柱头最适可授期在开花第2—3天;结合不同授粉处理表明:锦鸡儿自交不亲和,需要传粉者,为蜂媒兼鸟媒植物。  相似文献   

12.
The trinuclear complex [L2Cu3(CF3CO2)4] (1) has been synthesized and its crystal structure determined. It consists of a linear arrangement of Cu(II) centers. The central copper atom is bonded to six oxygen atoms and has a tetragonally distorted octahedral geometry, while the terminal copper atoms are bonded to three oxygen and two nitrogen atoms and show a distorted square pyramidal geometry. The complex shows di-μ(O,O′) syn-syn carboxylate bridging as well as monoatomic (μ-O) bridging, along with phenolate (μ-O) oxygen bridging. Cryomagnetic investigations in the range 2-300 K revealed an antiferromagnetic spin exchange interaction with J = −95.7 cm−1, based on the isotropic exchange model Hex = −2J[S1 · S2 + S2 · S3].  相似文献   

13.
海链藻(Thalassiosira)与圆筛藻(Coscinodiscus)的形态学比较研究   总被引:1,自引:0,他引:1  
李扬 《植物研究》2009,29(3):282-288
海链藻属(Thalassiosira)和圆筛藻属(Coscinodiscus)的种类繁多,是硅藻门中的大属和代表属。两者的形态学特征具有较多相似之处,易混淆鉴定。通过光学显微镜和电镜观察,比较研究了海链藻和圆筛藻种类的形态学特征。海链藻种类除了具有1~2个唇形突之外,还具有数量较多的支持突,少数种类具有闭合突;筛膜位于壳面内侧;中孔在壳面外侧。而圆筛藻种类只具有数量众多的唇形突,且其中两个较大;筛膜位于壳面外侧;中孔在壳面内侧。由于两属形态学特征的区别只有在电镜下才能清晰观察到,因此尚有较多的分类修订工作需要进行。  相似文献   

14.
论湖南海扇(Hunanopecten)   总被引:2,自引:0,他引:2  
湖南海扇属为张仁杰(1977)所建。现已描述的有H. exilis Zhang, H. qujiangensis Zhang, H. declivis Y. X. Zhang, H? longauriculus Yin等四种,后两种仅见于个别地点,一般所谈的湖南海扇主要指前两种。湖南海扇具有生物地层学、生态学和分类学意义,本文试图从这三方面给予论述。张仁杰同志惠赠原型照片以供比较,并提出宝贵意见,特致谢意。  相似文献   

15.
Mixed-ligand complexes of the type cis- and trans-Pt(Ypy)(pm)Cl2 where Ypy = pyridine derivative and pm = pyrimidine were synthesized and characterized by IR spectroscopy and by multinuclear (195Pt, 1H and 13C) magnetic resonance spectroscopy. The cis compounds were prepared from the reaction of K[Pt(Ypy)Cl3] with pyrimidine (1:1 proportion) in water, while most of the trans isomers were synthesized from the isomerization of the cis compounds. The cis isomers could not be isolated with the Ypy ligands containing two -CH3 groups in ortho positions. When the aqueous reaction of K[Pt(Ypy)Cl3] with pyrimidine was performed in a Pt:pm ratio = 2:1, the pyrimidine-bridged dinuclear species were formed. Only the most stable trans-trans isomers could be isolated pure. In IR spectroscopy, the cis monomers showed two ν(Pt-Cl) bands, while the trans monomers and dimers showed only one ν(Pt-Cl) band. The 195Pt NMR signals of the cis monomers were found at slightly higher fields than those of the corresponding trans isomers. The δ(195Pt) of the dimers were found close to those of the trans monomers. The NMR results were interpreted in relation to the solvent effect, which seems important in these complexes. The coupling constants J(195Pt-1H) and J(195Pt-13C) are larger in the cis geometry. The crystal structures of the compounds cis-Pt(2,4-lut)(pm)Cl2, trans-Pt(2,6-lut)(pm)Cl2 and trans,trans-Cl2(2,6-lut)Pt(μ-pm)Pt(Ypy)Cl2 were studied by X-ray diffraction methods and the results have confirmed the configurations suggested by IR and NMR spectroscopies.  相似文献   

16.
Reactions of [Pt2(μ-S)2(PPh3)4] with the diarylthallium(III) bromides Ar2TlBr [Ar = Ph and p-ClC6H4] in methanol gave good yields of the thallium(III) adducts [Pt2(μ-S)2(PPh3)4TlAr2]+, isolated as their salts. The corresponding selenide complex [Pt2(μ-Se)2(PPh3)4TlPh2]BPh4 was similarly synthesised from [Pt2(μ-Se)2(PPh3)4], Ph2TlBr and NaBPh4. The reaction of [Pt2(μ-S)2(PPh3)4] with PhTlBr2 gave [Pt2(μ-S)2(PPh3)4TlBrPh]+, while reaction with TlBr3 gave the dibromothallium(III) adduct [Pt2(μ-S)2(PPh3)4TlBr2]+[TlBr4]. The latter complex is a rare example of a thallium(III) dihalide complex stabilised solely by sulfur donor ligands. X-ray crystal structure determinations on the complexes [Pt2(μ-S)2(PPh3)4TlPh2]BPh4, [Pt2(μ-S)2(PPh3)4TlBrPh]BPh4 and [Pt2(μ-S)2(PPh3)4TlBr2][TlBr4] reveal a greater interaction between the thallium(III) centre and the two sulfide ligands on stepwise replacement of Ph by Br, as indicated by shorter Tl-S and Pt?Tl distances, and an increasing S-Tl-S bond angle. Investigations of the ESI MS fragmentation behaviour of the thallium(III) complexes are reported.  相似文献   

17.
Some novel hydrido-anions of general formula [Ir4H(CO)9(μ-L-L)] (L-L = Ph2PCH(CH3)PPh2, Ph2P(CH2)2PPh2, Ph2P(CH2)3PPh2 and Ph2AsCH2AsPh2) have been obtained by the reaction of [Ir4(CO)10(μ-L-L)] with the base 1,8-diazabicyclo[5.4.0]undec-7-ene in wet dichloromethane. According to IR and 1H, 31P and 13C NMR data at low temperature, these anionic derivatives display a single conformation in solution: three edge-bridging COs around the triangular basal face and both the hydride and the bidentate ligands located in axial positions relative to this face. The structures of four compounds were established by X-ray diffraction studies, which confirmed the configuration proposed on the basis of spectroscopic data.  相似文献   

18.
Direct reaction of copper(I) chloride with triphenylphosphine (tpp) in molar ratio 2:3 and 1:3, results in the formation of the [(tpp)Cu(μ2-Cl)2Cu(tpp)2] (1) and {[CuCl(tpp)3]·(CH3CN)} (2) complexes. The complexes have been characterized by melting point, FT-IR, UV-Vis spectroscopic data and X-ray crystallography. Complex 1 is di-nuclear. Two μ2-Cl atoms bridge two copper(I) ions with tetrahedral and trigonal geometry respectively. The short copper-copper bond distance of 2.9039(6) ? in case of 1 indicates d10-d10 interaction between metal centers. Thus, our studies were extended here in the determination of the quasi-aromaticity, which results in strong Cu-Cu interactions, using the computational method of nucleus-independent chemical shifts (NICS). The NICS calculated at the inner region of the Cu2Cl2P3 core in complex 1 is shielded up to −6.05 ppm. Complex 2 is mono-nuclear where three phosphorus and one chloride atoms form a tetrahedron around the copper(I) ion. Photolysis of both complexes 1 and 2, results in the formation of triphenylphosphine oxide.The complexes 1 and 2, were tested for their in vitro cytotoxic activity against leiomyosarcoma cells (LMS) and human breast adenocarcinoma cells (MCF-7). The type of LMS cell death caused by the complexes was also evaluated by use of a flow cytometry assay. The results show that at concentration of 5 μΜ of complexes 1 and 2, 34.1% (1) and 19.6 (2)% of LMS cells undergo programmed cell death (apoptosis), while at 10 μΜ, 80.4% (1) and 65.2% (2) of LMS cells undergo apoptosis. The light sensitivity of the complex is discussed in relation with the biological activity.  相似文献   

19.
滇西二叠纪Shanita-Hemigordius(Hemigordiopsis)有孔虫动物群   总被引:3,自引:1,他引:3  
近几年来,在亚洲一些地区二叠系,发现了一个大型有孔虫Shanita,常与Hemigordius(Hemigordiopsis)伴生,组成特提斯海区二叠纪颇具特色的动物群,分布在一定的区域范围,形成了特定的生物地理区。本文主要记述这一动物群在我国滇西地区的发现及其纵横分布情况。本文材料系云南省地质局第一区测队、云南省地质研究所等单位送来我所鉴定的,薄片、照相、绘图均由我所技术室承担,特此致谢。滇西潞西、腾冲、镇康一带二叠系较发育,由巨厚的白云质灰岩、灰岩及泥岩等组成,含有和中国南部其它地区(秦岭地区除外)不尽相同的有孔虫动物群。据云南省地质局第一区域地质测量大队工作结果,此区二叠系自上而下,大致分层如下: 上覆地层:中三叠统或侏罗系  相似文献   

20.
The reaction of cyanamide and its derivatives with the (η5-C5H5)Mn(CO)2(THF) and (η5-C5H4CH3)Mn(CO)2(THF) complexes affords the cyanamide substituted complexes of types (η5-C5H5)Mn(CO)2(NCN(R′)(R″)) (2a-d) and (η5-C5H4CH3)Mn(CO)2(NCN(R′)(R″)) (3a-e). All complexes were characterized by spectroscopy (1H, 13C NMR, IR), elemental and mass spectroscopy analysis. Complex 2b5-C5H5)Mn(CO)2(NCN(CH3)2) was additionally examined by single crystal X-ray structure determination.  相似文献   

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