THE CONDUCTIVITIES OF AQUEOUS SOLUTIONS OF GLYCINE,d,l-VALINE,AND l-ASPARAGINE

1. The conductivities of aqueous solutions of glycine, d,l-valine, and l-asparagine have been determined, and comparisons have been made with similar data reported in the literature. 2. On the basis of certain theoretical considerations, calculations of the expected conductivities of aqueous solutions of glycine, asparagine, aspartic acid, and glutamic acid have been made and these data have been compared with similar data obtained experimentally. 3. The dissociation constants of the carboxyl groups of aspartic acid and glutamic acid have been calculated from conductivity data. 4. It is shown that alanine has no effect on the ionic atmosphere of solutions of potassium chloride.     

Plagiochilines C,D, E and F,four novel secoaromadendrane-type sesquiterpene hemiacetals from Plagiochila asplenioides and Plagiochila semidecurrens

Four novel secoaromadendrane-type sesquiterpene hemiacetals, plagiochilines C, D, E and F, together with the previously known (?)-bicyclogermacrene, have been isolated from the liverwort, Plagiochila asplenioides and their structures have been spectroscopically elucidated. From Plagiochila semidecurrens plagiochilines A and C have been obtained along with (?)-bicyclogermacrene and its related sesquiterpene hydrocarbons.     

Conodont biostratigraphy of the Upper Devonian-Lower Carboniferous Shahmirzad section, central Alborz, Iran

The conodont fauna from the Devonian-Carboniferous Shahmirzad section, located in the Central Alborz Mountains (North Iran), have been studied mainly for biostratigraphic purposes. Some levels were barren of conodonts, whereas others yielded a not very abundant, but quite differentiated fauna. No conodonts have been found from the mainly terrigenous and shaly Geirud Formation, whereas representative of genera Bispathodus, Clydagnathus, Gnathodus, Hindeodus, Mehlina, Polygnathus, Protognathodus, Pseudopolygnathus and Siphonodella have been collected from the mainly calcareous overlaying Mobarak Formation. The fauna allowed to discriminate five biointervals, from the sulcata Zone to a “Lower typicus - anchoralis-latus interval” in the central part of the section, while the lower and upper parts cannot be zoned on the basis of conodonts. This paper is the first report on lowermost Carboniferous conodonts from the Mobarak Formation in central Alborz.     

Alcaloïdes dihydrofuroquinoleiques de quelques rutaceae: Isolement,structure, proprietes biologiques

Six dihydrofuroquinoline quaternary bases have been isolated from Choisya ternata, Ptelea trifoliata and Ruta graveolens. Their structures have been determined by spectrometry and for some, the absolute configuration is reported. Some of the six isolated alkaloids have a prominent cytotoxic action on plant and animal tumor cells, and an inhibitory effect on Gram-positive bacteria.     

Fish remains from the Plio-Pleistocene Shungura Formation, Omo River basin, Ethiopia

Thousands of vertebrate fossils have been recovered from the lower Omo River Valley, in southern Ethiopia, however, fishes have been poorly reported. Here we describe fossil fish remains deriving from the Shungura Formation, part of the Omo Group of deposits ranging in date from 1.8 to 3.4 my. Two new species are reported, Sindacharax omoensis (Characiformes) and Lates arambourgi (Perciformes), which suggest greater diversity of these genera than previously documented.     

Italian Cenozoic crocodilians: taxa, timing and palaeobiogeographic implications

Crocodylian remains are collected in 39 fossil-bearing localities but only in seven localities specimens with reliable taxonomic attributions, at least to genus level have been collected. Three species have been reported from the early Lutetian Purga di Bolca site: Pristichampsus cf. Pristichampsus rollinati, Asiatosuchus sp., Hassiacosuchus sp. (=Allognathosuchus sp.). The three crocodilians discovered at Purga di Bolca have been reported also from Geiseltal and Messel (Middle Eocene, Germany). Bolca at that time was part of a Tethysian archipelago and no mammals have been found there till now. Crocodilians and turtles clearly arrived from the European mainland across a marine water barrier. Among the other fossiliferous localities of Veneto, very interesting is the Monte Zuello site, of late Middle Eocene age, yielding a longirostrine crocodilian, Megadontosuchus arduini, a tomistomine species. Tomistomines are known in contemporaneous sediments of both Europe and Africa, but the European forms Dollosuchus and Kentisuchus seem the closest taxa. Remains of Oligocene age have been collected in Veneto and Liguria, but the fossils discovered in the second region are teeth or fragmented bones. The fossil crocodilians of Monteviale (Veneto), of Early Oligocene age, have been assigned to two species but they have been recently all identified as Diplocynodon ratelii, known from several European sites of Late Eocene, Oligocene and Miocene age. This species arrived in the Monteviale area from the European mainland across a narrow sea. Several crocodilian fossils of Miocene age are very fragmentary or represented by isolated teeth. In the Middle and Late Miocene of Sardinia, a well-established species, Tomistoma calaritanum is present. Remains of Tomistoma of the same age have been reported in some localities in Tuscany, Apulia, Sicily and Malta. In the Mediterranean area, the genus is known from European and African sites (of older age). The colonisation of Europe by this genus is the result of a dispersion from Africa (or less probably from Asia). During Late Miocene Sardinia and Tuscany belong to the same palaeobioprovince characterized by the Oreopithecus-Maremmia fauna. In Tuscany, a crocodilian identified as Crocodylus bambolii is present in the late Miocene site of Monte Bamboli. If the generic attribution of this form is correct, its ancestors must have arrived from Africa. Another fossil assemblage of Late Miocene age characterizes the Apulia-Abruzzi palaeobioprovince (Hoplitomeryx-Microtia fauna) and testifies complete isolation between the two palaeobioprovinces. In this last area, remains of Crocodylus sp. have been collected in coastal sandstones at Scontrone (Abruzzi) and in several fissure fillings of Gargano of slightly younger age. The ancestors of this species arrived from Africa while no African elements are present among the mammalian fauna. The dispersion of the genus Crocodylus in the Italian palaeoislands may have taken place once, with allopatric differentiation of the two populations (Tuscany-Sardinia and Apulia-Abruzzi) or twice with independent colonisation of each area.     

Ectoparasites of the particolored bat (Vespertilio murinus Linnaeus, 1758, Chiroptera,Mammalia) in the Urals and adjacent regions

The ectoparasite fauna on the most widespread synanthropic chiropteran species, the particolored bat (Vespertilio murinus L., 1758), is described from localities in the Urals and West Siberia. 86 individual bats have been examined, off which 463 ectoparasite specimens from 8 species have been collected. The species composition and ecology of these arthropods are analyzed. The core of the ectoparasite fauna on the particolored bat in the Urals has been found to consist of gamasine mites of the genus Steatonyssus.     

Free-ranging black howler monkeys, Alouatta pigra, in southern Belize are not parasitized by Controrchis biliophilus

Several coprological studies of Alouatta pigra, the black howler monkey, inhabiting Belize and Mexico have been published in the past several years. Trematodes, specifically Controrchis biliophilus (Dicrocoeliidae), have been detected in A. pigra from all locations in Belize and Mexico examined in those studies. A routine coprological survey of A. pigra was conducted in May and June 2010 as part of baseline data collection for an A. pigra population in Punta Gorda, Toledo District, southern Belize. The 51 fecal samples collected in this area were all negative for C. biliophilus. Subsequently, two additional fecal samples were collected from another population of A. pigra in Toledo District and 25 additional fecal samples were collected from six other areas of Belize during December 2010 and January 2011 and were examined for parasites. To date, C. biliophilus eggs have been detected in fecal samples from A. pigra inhabiting every district of Belize except Toledo District in southern Belize. This finding is notable, for no other population of A. pigra completely free of C. biliophilus infection had been located prior to this study.     

Pfaffosides,nortriterpenoid saponins,from Pfaffia paniculata

Three new nortriterpene saponins having inhibitory effects on the growth of cultured tumor cells, named pfaffosides D, E and F, have been isolated from Pfaffia paniculata. Their structures have been established as 3β-O-[β-d-xylopyranosyl-(1 → 2)-β-d-(6-O-n-butyl) glucuronopyranosyl]-pfaffic acid-(28 → 1)-β-d-glucopyranosyl ester, 3β-O-[β-d-xylopyranosyl-(1 → 2)-β-d(6-O-methyl)glucuronopyranosyl]-pfaffic acid-(28 → 1)-β-d glucopyranosyl ester and 3β-O[β-d-glucuronopyranosyl]-pfaffic acid respectively, based on their chemical and spectroscopic properties     

Ostracodes turoniens de la region de Cassis,La,Bedoule (Bouches-du-Rhone,France): Associations et affinites paleogeographiques

The study of 15 species of ostracods from the Turonian of Provence is especially concernedin this paper; two new species are proposed: Mauritsina provencialis nov. sp. and Spinoleberis ectypus nov. sp.Two associations can have been recognized: one in the marly lower Turonian, theother in the zone of transition from the lower to the upper Turonian.These ostracods are replaced in the general stratigraphic context of the country and some comparisons can have been made with others countries.Some ecologic and paleogeographic remarks are proposed to contribute for a betterknowledge of the paleoenvironments.     

Structure and development of the style base in Abildgaardia, Bulbostylis, and Fimbristylis (Cyperaceae,Cyperoideae, Abildgaardieae)

The Abildgaardieae tribe within the family Cyperaceae comprises six or seven genera, among which Abildgaardia, Bulbostylis and Fimbristylis pose a challenge regarding their morphological delimitation. Molecular phylogenetic analyses including species of Abildgaardieae are rare, but in most of those studies, Abildgaardia and Fimbristylis appear as more closely related to each other than to the Bulbostylis genus. Duration of the style base has been one of the most widely used characters for delimiting these three genera. The style base is a persistent structure in most species of Bulbostylis and deciduous in Abildgaardia and Fimbristylis. The reasons why the style base may persist or fall off have been scarcely discussed. The assumption that abscission layers are present in the style base of all three genera and the fact that tracheids have been observed in the style base of Bulbostylis suggest that this structure might have histological complexity. In view of this, a complete ontogenetic and anatomical study of the gynoecium has been carried out for all these three genera. It turned out that the style base is histologically simple in Abildgaardia, Bulbostylis and Fimbristylis and shows similar structure and development in all three genera. The fact that the style base has a shorter duration in Abildgaardia and Fimbristylis than in Bulbostylis might be related to the lower number of sclerotised cells that make up such structures in the mature fruit of the former two genera. Abscission of the style and style base may be the result of much simpler reasons than the differentiation of an abscission layer, resulting merely from mechanical shear force effects. Differences among genera have been observed in the shape of the style base and the development of the style. The histological simplicity of the style base is consistent with the homoplastic appearance of this structure in genera that are not closely related (e.g. Rhynchospora). Because of this, while the presence of the thickened style base seems to be a synapomorphy in species of Abildgaardieae, its persistence on or detachment from the fruit might have emerged repeatedly during this clade evolution and might not be a suitable character for genera delimitation.     

Devonian (Eifelian) disparid crinoids from the Zeravashan range,southern Tien Shan,Uzbekistan

No Devonian disparid crinoids have been described from Uzbekistan, although parahexacrinid thecae and assorted columnals have been described in several papers in the past 50 years. Discovery of a cup of Pisocrinus and a thecae of Haplocrinites are the first of these genera known from Uzbekistan. The stratigraphic range of Haplocrinites is revised to be late Early Devonian (Emsian) to Early Carboniferous (Tournaisian) because Silurian species assigned to the genus are based on loose ossicles that morphologically do not belong to the genus. The paleogeographic ranges of Pisocrinus and Haplocrinites are extended into Uzbekistan. Haplocrinites uzbekistanensis n. sp. is described.     

Alkaloids of Uncaria attenuata,U. orientalis and U. Canescens

3-Iso-19-epi-ajmalicine, epiallo-corynantheine and dihydrocorynantheine pseudoindoxyl, not previously known as natural products, have been isolated from samples of U. attenuata. Akuammigine, dihydrocorynantheine, hirsutine, hirsuteine, mitraphylline, speciophylline, uncarines A and B, isorhynchophylline rhynchophylline, isocorynoxeine, corynoxeine, corynoxine B, rotundifoline, speciofoline, two yohimbine isomers, a yohimbine oxindole and an unidentified indole alkaloid (M⁺, m/e 347) have been obtained from samples of the same species. 3-Iso-ajmalicine, harmane, isopteropodine, pteropodine, uncarine F, speciophylline, isomitraphylline, mitraphylline and N-oxides of these six oxindole alkaloids have been isolated from samples of U. orientalis. Several samples of U. canescens have yielded harmane while one sample contained the four pteropodine isomers. The variation in the alkaloid content of these three species is discussed.     

Pinguisanin,pinguisanolide and β-pinguisenediol,three new pinguisane-type sesquiterpenes from Porella platyphylla

Three new pinguisane-type sesquiterpenes, pinguisanin, pinguisanolide and β-pinguisenediol, together with the previously known deoxopinguisone, have been isolated from a European liverwort, Porella platyphylla, and their structures have been established by the spectral evidence and some chemical transformations.     

In vitro selection, characterization, and application of deoxyribozymes that cleave RNA

Over the last decade, many catalytically active DNA molecules (deoxyribozymes; DNA enzymes) have been identified by in vitro selection from random-sequence DNA pools. This article focuses on deoxyribozymes that cleave RNA substrates. The first DNA enzyme was reported in 1994 and cleaves an RNA linkage. Since that time, many other RNA-cleaving deoxyribozymes have been identified. Most but not all of these deoxyribozymes require a divalent metal ion cofactor such as Mg²⁺ to catalyze attack by a specific RNA 2′-hydroxyl group on the adjacent phosphodiester linkage, forming a 2′,3′-cyclic phosphate and a 5′-hydroxyl group. Several deoxyribozymes that cleave RNA have utility for in vitro RNA biochemistry. Some DNA enzymes have been applied in vivo to degrade mRNAs, and others have been engineered into sensors. The practical impact of RNA-cleaving deoxyribozymes should continue to increase as additional applications are developed.     

Siluro-Devonian miospore biostratigraphy of the Urubu River area, western Amazon Basin, northern Brazil

Well-preserved miospores have been observed in the Urubu River area from the western part of the Amazon Basin, northern Brazil, in rocks belonging to the uppermost Pitinga and Manacapuru Formations. A previous palynological work based on chitinozoans has dated these strata as Late Ludlow, Early Pridoli and Early Lochkovian. Although samples are relatively poor in miospores, the present study reveals the most diversified Silurian-Earliest Lochkovian palynoflora ever reported from South America, an interval where miospore information is still very rare. Sixty-four species have been identified, of which two are new (Artemopyra urubuense and Retusotriletes amazonensis). One single specimen attributed to the genus Grandispora, identical to unpublished forms identified by one of us (P.S.) in Lochkovian sections of Saudi Arabia, has been found in a Lochkovian sample from the Urubu River. These constitute the oldest geological record of Grandispora. Among the abundant acritarchs, specimens of the genus Schizocystia have been observed for the first time in pre-Devonian rocks.Although the Late Silurian-Early Lochkovian miospore biostratigraphy is still in its infancy in South America, it seems that Amazon Basin assemblages do not show significant differences in composition in comparison to coeval palynofloras from other areas of northwestern Gondwana. This is surprising since the miospore localities under consideration are widely distributed over high to low paleolatitudes, i.e. from cool temperate to dry subtropical belts. Conversely, Siluro-Devonian Gondwanan assemblages differ considerably from the contemporary palynofloras of the Old Red Sandstone Continent and adjacent areas, thus contradicting recent phytogeographic interpretations based on megafloras.     

Iridodial,and a new alkanone, 4-methylhexan-3-one,in the defensive secretion of the beetle, Staphylinus olens

The monoterpene iridodial and the ketone, 4-methylhexan-3-one, have been identified as the major components of the defensive secretion from Staphylinus olens.     

Isolation and structure of 13,18-dehydroexcelsin,a quassinoid,and glaucarubol from Ailanthus excelsa

A new quassinoid, 13,18-dehydroexcelsin and glaucarubol have been isolated from the bark of Ailanthus excelsa.