58 research outputs found
A review and revision of the Jurassic-Early Cretaceous Globigerinina, with especial reference to the Aptian assemblages of Speeton (North Yorkshire, England)
No full textAbstract. The classification of the Jurassic to Albian Globigerinina is revised, phyletically and taxonomically. The Favusellacea comprise the genera Globuligerina (Jurassic) and Conoglobigerina (Jurassic-earliest Cretaceous), its descendant Favusella (Hauterivian to Cenomanian) and Ascoliella nov. (type species A. scotiensis nov.) (Aptian-Albian). The Globigerinacea include the families Praehedbergellidae nov. (from which the Hedbergellidae and its allies are descended) and the Schackoinidae; both are microperforate and nonmuricate. The Praehedbergellidae originate with Gorbachikella nov. (type species G. kugleri (Bolli)) and include Praehedbergella (Hauterivian-Aptian, including P. tatianae nov., P. grigelisae nov.), Wondersella, Blefuscuiana nov. (including B. kuznetsovae nov., B. mitra nov., B. multicamerata nov., B. speetonensis nov., B. globigerinelloides (Subbotina) lobulata nov. and B. occulta (Longoria) quinquecamerata nov.) (Barremian to Danian) and Lilliputianella nov. (including L. longorii nov.) (Aptian). The Schackoinidae includes Blowiella, Leupoldina and Schackoina. All the genera have their diagnoses emended as they are reinterpreted in accordance with the revised phyletic classification. Suggestions are made to explain the adaptive evolution of the taxa to the developing Early Cretaceous ocean.
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Homoarginine, the methylene homologue of arginine, as a substrate of human arginine:glycine amidinotransferase and arginases
No full textL-homoarginine (hArg) is a non-coding amino acid, the blood level reduction of which is associated with an increased risk of stroke and heart attack. In humans and animals, hArg is mainly formed during the reaction catalyzed by the enzyme of the metabolic pathway of creatine biosynthesis:arginine: glycine amidotransferase (AGAT, EC 2.1.4.1), in the case where L-lysine acts instead of glycine as an acceptor of the arginine amidine group. It has been shown that hArg can serve for nitric oxide biosynthesis which is seemed a single significant enzymatic pathway established for hArg.The aim of this study was to investigate hArg as a substrate human AGAT and arginases.Materials and methods. In experiments with recombinant enzymes we established that Km for hArg in the reaction catalyzed by AGAT towards the formation of guanidinoacetic acid is 12.0 ± 1.1 mM. In reactions catalyzed by both types of arginase activity against hArg, unlike arginine, was not detected.Conclusions. Thus, the present study established that hArg may be considered as a substrate of AGAT additionally to nitric oxide synthases. Metabolic value of hArg, in addition to regulation of vascular tone, can be associated with cell energy metabolism. According to our data a decrease of hArg blood levels in cardiovascular diseases appears to be unrelated to a detectable increase of arginase activity
Homoarginine, the methylene homologue of arginine, as a substrate of human arginine:glycine amidinotransferase and arginases
No full textTaxonomy and phylogeny of Albian-Maastrichtian planispiral planktonic foraminifera traditionally assigned to Globigerinelloides
No full textWe propose a considerably revised taxonomy and phylogeny for Albian-Maastrichtian planispiral planktonic foraminiferal species that have traditionally been included in Globigerinelloides. The revised taxonomy is necessary because of a similar to 6 m.y. gap between the extinction of planispiral species during the late Aptian and the next younger occurrence of planispiral species in the middle Albian. Our stratophenetic taxonomic groupings utilize ontogenetic morphometric data, shell wall ultrastructure, and general morphologic features observed from Scanning Electron Microscope and X-radiograph images of primary type specimens and globally distributed hypotype specimens.The planispiral lineage Laeviella n. gen., whose type species is La. bentonensis (Morrow), first appeared in the middle Albian and is postulated to have evolved from the evolutionary series Ticinella primula Luterbacher-Laviella primuloides n. sp. Laeviella is characterized as having a smooth to finely pustulose wall texture and a moderate chamber size increase rate. Two additional species, La. tururensis (Bronnimann) and La. bollii (Pessagno), are included in Laeviella with the youngest species of the genus, La. bollii, becoming extinct during the late Campanian.Planohedbergella, with Plh. aspera (Ehrenberg) as its type species, is revised to include 10 species that show a wide variation in chamber arrangement, wall microstructure and test morphology, but all have a moderately to coarsely pustulose wall texture on some or most final whorl chambers. Its stratigraphic range is from the late Albian-Cretaceous/Paleogene boundary. The oldest species is Plh. ultramicra (Subbotina), which evolved from Planomalina pulchella Todd and Low during the late Albian. Planohedbergella circularis n. sp. is described as a new late Campanian-Maastrichtian species representing forms with evolute coiling, a large number of final whorl chambers, and a slow chamber size increase rate.Polycamerella n. gen. is described as a monospecific genus, with Po. tardata n. sp. as the type species. It is a small, biapertural form with a very slow chamber expansion rate and a stratigraphic range from the late Campanian-Maastrichtian. The ancestor of Po. tardata, is tentatively identified as Plh. ultramicra
Effect of Mn Promoter on Sulfated ZrO<sub>2</sub> Studied by IR Spectroscopy
No full textIntroduction: Addition of Mn increases the activity of sulfated zirconia ("SZ") for n-butane isomerization [1] by 2-3 orders of magnitude [2]. To clarify the role of the promoter, SZ and Mn-promoted SZ ("MnSZ") and their interaction with H2 and n-C4H10 were investigated by IR spectroscopy. Experimental: SZ was prepared by calcining hydrous sulfated zirconia (SZH, MEL Chemicals) in flowing air at 823 K for 3 h. MnSZ (2 wt% Mn) was obtained through incipient wetness impregnation of SZH with Mn(NO3)2 aq. solution and calcination at 923 K for 3 h. Samples were pressed (2 s, 10 MPa), sieved (0.5-1.0 mm), and activated in vacuum at 723 K. Spectra were recorded with a Nicolet “Impact 410” FTIR spectrometer and a home-made diffuse reflectance attachment. Results and Conclusions: The spectra of the activated samples were characterized by OH and SO vibrations and were similar with respect to the band positions. H2 adsorption at 77 K produced bands at 4047 (SZ) and 4059 (MnSZ) cm 1, indicating no significant difference in the Lewis acid strength. Heating to 473 K in H2 (ca. 65 hPa) did not affect SZ, but the spectrum of MnSZ showed a new OH stretching band at ca. 3580 cm 1, a decrease of the bands belonging to sulfate vibrations, and formation of water on the surface. After contact with n-C4H10 (ca. 15 hPa) at 373 K, SZ was largely unaffected except for slight changes (shifts) in the OH region. At 573 K the sulfate bands shrank, and vibrations of olefinic CH and water were observed. MnSZ showed significant intensity increase in the OH region already after interaction with n-C4H10 at 373 K. Additionally, a slight decrease of the sulfate bands, and formation of water were detected. Promotion of sulfated zirconia by Mn thus modifies the reactivity of the sulfate groups, facilitating their easier interaction with reducing agents. 1. Hino, M., Kobayashi, S., and Arata, K., J. Am. Chem. Soc. 101, 6439 (1979). 2. Lange, F.C., Cheung, T.-K., and Gates, B.C., Catal. Lett. 41, 95 (1996)
Levels of amino acids and homoarginine in the venous basins of the brain and the heart muscle in patients with ischemic heart disease
No full textIntroduction. Under the conditions of circulatory disorders and coronary heart disease (CHD), amino acids acquire additional value as a source of intermediates of Krebs cycle, participating in cell energetics. If there is a disturbance of energy metabolism, the level of amino acids in the blood can change, including the minor non-encoding amino acid homoarginine (hArg).The objective of this study was to compare the shifts in the levels of hArg and other amino acids in the venous blood flowing from the tissues of the heart and brain versus their levels in blood plasma from the cubital vein in patients with CHD.Methods and materials. The study used plasma samples of 58 patients (46 men and 12 women) aged 62 (57 — 66) years with CHD and heart failure of functional class III (NYHA). The level of hArg and the spectrum of 22 other amino acids were determined by the reversed-phase high-performance liquid chromatography (HPLC). Besides, the levels of lactic acid (LA) were determined by spectrophotometric method, as well as routine biochemical parameters were determined using standard kits.Results. Patients with CHD had compensated, without significant deviations, biochemical data of glucose level, lipid and nitrogen metabolism profiles. The level of hArg in the patient group of 1.4 (1.0—1.9) p.M was significantly lower compared to the reference interval, and the level of total homocysteine was increased, although there were no differences depending on the venous basin. The highest concentrations of LA, alanine and glutamine were detected in the plasma from the internal jugular vein. At the same time, lower concentrations of arginine, lysine and alanine corresponded to the lowest values of hArg.Conclusion. In patients with CHD and heart failure, a significant increase in the levels of glutamine and alanine in plasma from the internal jugular vein and coronary sinus in comparison with plasma from the cubital vein was accompanied by profound dysregulation of energy metabolism with the decrease in hArg levels
Monoschelobates parvus Balogh and Mahunka 1969
No full textMonoschelobates parvus Balogh and Mahunka, 1969 (Figure 3) Diagnosis — Body size: 282 – 315 × 166 – 199. Rostrum rounded. Prodorsal setae long, setiform, barbed. Sensilli clavate, weakly barbed. Translamellar line represented by rudimentary parts. Prolamellar lines present. Notogaster with ten pairs of short setae. Aggenital setae absent. Leg claws serrate on dorsal side. Description — Measurements. Body length: 282-315 (six specimens); notogaster width: 166-199 (six specimens). Integument — Body color light brown. Body surface smooth. Prodorsum — Rostrum rounded. Lamellae located dorso-laterally, as long as half of prodorsum (in lateral view), without cusps. Translamellar line represented by rudimentary parts near to lamellae. Prolamellar and sublamellar lines distinct. Sublamellar porose areas (Al) very small (2 – 4 × 1 – 2), oval. Rostral (28-32), lamellar (36-45) and interlamellar (61 – 65) setae setiform, barbed. Sensilli (53 – 65) clavate, with well dilated head, having small barbs. Exobothridial setae (2) minute. A pair of elongate, narrow porose areas present (visible in dissected specimens) latero-posterior to interlamellar setae. Notogaster — Anterior notogastral margin convex medially. Dorsophragmata small. Ten pairs of thin, smooth notogastral setae present; setae c and la (8) slightly longer than others (4 – 6). Four pairs of sacculi (Sa, S1, S2, S3) oval, with small openings. Epimeral and lateral podosomal regions — Apodemes 1, 2, 3 and sejugal apodemes distinct. Epimeral setal formula: 3-1-3-3. Setae setiform, thin, smooth; medial setae 1a, 2a, 3a (4) shorter than others (8 – 12). Pedotecta I large, convex, pedotecta II rounded anteriorly. Discidia rounded distally. Circumpedal carinae distinct. Anogenital region — Four pairs of genital (4), two pairs of anal (4) and three pairs of adanal (8 – 12) setae setiform, thin, smooth. Aggenital setae absent. Lyrifissures iad in paraanal position. Legs — Each claw with several minute barbs on dorsal side. Formulae of leg setation and solenidia: I (1-5-3-4-19) [1-2-2], II (1-5-2-4-15) [1-1-2], III (2-3- 1-3-15) [1-1-0], IV (1-2-2-3-12) [0-1-0]; homology of setae and solenidia indicated in Table 1. Material examined — Three specimens (two females and one male): Ec-1 (1.IV.2009, collected by F. Marian). Three specimens (one female and two males): Ec-1 (1.X.2008, collected by F. Marian). Remarks — Ecuadorian specimens of Monoschelobates parvus are similar in general appearance to Brazilian specimens (Balogh and Mahunka 1969; Balogh and Balogh 1990), but there is a clear difference: prolamellar lines present versus absent in Brazilian specimens. Sometimes presence or absence of prolamellar lines or their partial development can vary in specimens of one species in Scheloribatidae: for example, prolamellar lines in Scheloribates fimbriatus Thor, 1930 - present (see Subbotina 1978), developed partially (Mahunka 1987), indistinctly visible or absent (data of first author, based on specimens from Western Europe); similar situation is known for Scheloribates (Bischeloribates) mahunkai Subías, 2010 (Ermilov 2013). Hence, we assume this difference to represent intraspecific variability in the case of M. parvus.Published as part of Ermilov, S. G., Sandmann, D., Marian, F. & Maraun, M., 2013, Perscheloribates Paratzitzikamaensis N. Sp., With Supplementary Descriptions Of Scheloribates Elegans And Monoschelobates Parvus (Acari, Oribatida, Scheloribatidae) From Ecuador, pp. 429-437 in Acarologia 53 (4) on pages 434-436, DOI: 10.1051/acarologia/20132104, http://zenodo.org/record/463996
Гомолог аргинина гомоаргинин в качестве субстрата аргинин: глицинамидинотрансферазы и аргиназ человека
No full textL-homoarginine (hArg) is a non-coding amino acid, the blood level reduction of which is associated with an increased risk of stroke and heart attack. In humans and animals, hArg is mainly formed during the reaction catalyzed by the enzyme of the metabolic pathway of creatine biosynthesis:arginine: glycine amidotransferase (AGAT, EC 2.1.4.1), in the case where L-lysine acts instead of glycine as an acceptor of the arginine amidine group. It has been shown that hArg can serve for nitric oxide biosynthesis which is seemed a single significant enzymatic pathway established for hArg.The aim of this study was to investigate hArg as a substrate human AGAT and arginases.Materials and methods. In experiments with recombinant enzymes we established that Km for hArg in the reaction catalyzed by AGAT towards the formation of guanidinoacetic acid is 12.0 ± 1.1 mM. In reactions catalyzed by both types of arginase activity against hArg, unlike arginine, was not detected.Conclusions. Thus, the present study established that hArg may be considered as a substrate of AGAT additionally to nitric oxide synthases. Metabolic value of hArg, in addition to regulation of vascular tone, can be associated with cell energy metabolism. According to our data a decrease of hArg blood levels in cardiovascular diseases appears to be unrelated to a detectable increase of arginase activity.L-гомоаргинин (гАрг) является некодируемой аминокислотой, снижение в крови уровня которой ассоциировано с повышением риска развития инсульта и инфаркта. В организме человека и животных гАрг образуется преимущественно в ходе реакции, катализируемой ферментом метаболического пути биосинтеза креатина – аргинин:глицинамидинотрансферазой (АГАТ, КФ 2.1.4.1), в случае, когда акцептором амидиновой группы аргинина вместо глицина выступает L-лизин. Метаболическое значение и причины снижения уровня гАрг в настоящее время изучены недостаточно.Цель настоящего исследования – изучение возможности утилизации гАрг в качестве субстрата АГАТ и аргиназ человека.Материалы и методы. В ходе экспериментов с рекомбинантными ферментами обнаружено, что Кm для гАрг в реакции, катализируемой АГАТ, в сторону образования гуанидинуксусной кислоты составляет (12,0 ± 1,1) мМ. В реакциях, катализируемых аргиназами обоих типов, активность в отношении гАрг, в отличие от аргинина, не регистрировалась.Заключение. Таким образом, в результате проведенного исследования установлено, что у человека гАрг является субстратом не только для NO-синтаз, но также для АГАТ. Полученные данные указывают на то, что метаболическое значение гАрг, помимо регуляции сосудистого тонуса, может быть связано с участием в энергетическом обмене клеток. Согласно представленным данным, снижение уровня гАрг в крови при сердечно-сосудистых заболеваниях, по всей видимости, не связано с обнаруживаемым повышением активности аргиназ
The impact of general anesthesia on methionine metabolism during cardiopulmonary bypass
No full textIt has been found out that methylation of nucleic acids, proteins and low-molecular substrates is necessary to renew cellular structures, their restoration and cytoprotection. Methionine plays the most important role in this process but whether its metabolism changes during anesthesia and how different anesthetics affect it, has not yet been studied.The objective: to study the metabolism of methionine during cardiopulmonary bypass when the direct myocardial revascularization is performed and the impact of the anesthetics used (propofol, desflurane, and sevoflurane) on methionine metabolism.Subjects and methods: 74 patients who underwent surgery due to coronary heart disease with cardiopulmonary bypass were enrolled in the study. The patients were divided into three groups by the anesthetic used (desflurane, sevoflurane, propofol). Levels of methionine, homocysteine, cysteine, and taurine were tested in the blood collected from veins and jugular vein before the aorta clamping and after the release of clamps.Results. In all three groups, lower levels of methionine and a higher level of homocysteine were observed after the release of clamps from the aorta, especially in the jugular vein. The most significant consumption of methionine was noted when propofol was used. In the same group, the exocytic release of homocysteine into the blood and the formation of cysteine were significantly lower. No significant difference was observed in the effect of desflurane and sevoflurane on methylation.Conclusion. During the anoxia, the consumption of methionine increases significantly but the intensity of demethylation/remethylation depends on the anesthetics used during anesthesia. The most significant decrease in the level of methionine as well as the remethylation of homocysteine into methionine occurs with the use of propofol, rather than inhalation anesthetics which may be a consequence of desflurane and sevoflurane cytoprotective properties
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