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171.
MATÍAS MORA ADRIANA ITATÍ OLIVARES ALDO I. VASSALLO 《Biological journal of the Linnean Society. Linnean Society of London》2003,78(1):85-96
Morphological analysis of the skull of the subterranean rodent Ctenomys , a highly speciose genus which uses both claws and teeth when digging, shows that for a broad range of species size, scaling was associated with both variation and maintenance of shape. Our results show that the angle of incisor procumbency (AIP), a character largely viewed as an adaptation to digging with teeth, is highly variable. We found a non-significant relationship between AIP and basicranial axis (basioccipital + basisphenoid) length, a measure of overall skull size. Accordingly, both small and large Ctenomys species possess either high or low AIP. A significant relationship between AIP and diastema length, given the rostral allometry seen in Ctenomys , suggests that hypermorphosis to a certain extent influences AIP. However, the roots of the incisor are lateral to those of the cheek teeth and their position may thus shift freely. This observation supports the notion that skull structural design, and to a certain extent rostral allometry, underlies variation in AIP. On the other hand, the positive allometry of incisor width and thickness indicates that, in larger species, proportionately powerful incisors are able to resist greater bending forces. We found that the out-lever arm of the jaw adductor muscles scales with positive allometry against basicranial axis length. However, we found an isometric relationship between in- and out-lever arms. In this case, conservation of skull proportions, regardless of variation in size, is a feature possibly related to the maintenance of an effective tooth digging capability. Functional and ecological data are discussed when assessing the implications of size and shape variation in the skull of Ctenomys . © 2003 The Linnean Society of London. Biological Journal of the Linnean Society , 2003, 78 , 85−96. 相似文献
172.
Composition and Chemical Variability of Cleistopholis patens Trunk Bark Oil from Côte d'Ivoire
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Zana A. Ouattara Jean Brice Boti Coffy Antoine Ahibo Yves‐Alain Bekro Mamyrbekova Janat Joseph Casanova Félix Tomi Ange Bighelli 《化学与生物多样性》2017,14(2)
The chemical composition of trunk bark oil from Cleistopholis patens (Benth .) Engl . & Diels , growing wild in Côte d'Ivoire, has been investigated by GC (FID) in combination with retention indices, GC/MS and 13C‐NMR. Moreover, one oil sample has been subjected to CC and all the fractions analyzed by GC (RI) and 13C‐NMR. In total, 61 components have been identified, including various sesquiterpene esters scarcely found in essential oils. 13C‐NMR was particularly efficient for the identification of a component not eluted on GC and for the quantification of heat‐sensitive compounds. Then, 36 oil samples, isolated from trunk bark harvested in six Ivoirian forests have been analyzed. The content of the main components varied drastically from sample to sample: (E)‐β‐caryophyllene (0.4 – 69.1%), β‐pinene (0 – 57%), α‐phellandrene (0 – 33.2%), α‐pinene (0.1 – 30.6%), β‐elemol (0.1 – 29.9%), germacrene D (0 – 25.4%), juvenile hormone III (0 – 22.9%), germacrene B (0 – 20.6%) and sabinene (tr‐20.3%). Statistical analysis, hierarchical clustering and principal components analysis, carried out on the 36 compositions evidenced a fair chemical variability of the stem bark oil of this species. Indeed, three clusters have been distinguished: the composition of group I (ten samples) was dominated by β‐pinene and α‐pinene, group II (nine samples) was represented by α‐phellandrene and p‐cymene and group III (16 samples) by β‐elemol. A sample displayed an atypical composition dominated by (E)‐β‐caryophyllene. 相似文献
173.
Cloning, expression, purification, and characterization of the acid alpha-mannosidase from Trypanosoma cruzi 总被引:1,自引:0,他引:1
Vandersall-Nairn AS; Merkle RK; O'Brien K; Oeltmann TN; Moremen KW 《Glycobiology》1998,8(12):1183-1194
The acid alpha-mannosidase of Trypanosoma cruzi is a broad-specificity
hydrolase involved in the catabolism of glycoconjugates, presumably in the
digestive vacuole. We have cloned the alpha-mannosidase gene from a T.cruzi
epimastigote genomic library. The alpha-mannosidase gene was determined to
be single copy by Southern analysis, and similar sequences were not
detected in genomic digests of either Trypanosoma brucei or Leishmania
donovani. The coding region was subcloned into the Pichia pastoris
expression vector pPICZ, and alpha-mannosidase activity was detected in the
medium of induced cultures. The recombinant alpha- mannosidase demonstrated
a pH optimum, inhibition by swainsonine, Km, and substrate specificity
consistent with the characteristics of the alpha-mannosidase previously
purified from T.cruzi epimastigotes. The recombinant enzyme was purified
103-fold from the culture medium of Pichia pastoris and had a native
molecular mass of 359 kDa by gel filtration. A combination of SDS-PAGE,
deglycosylation with endo H, and NH2-terminal sequencing indicates that the
enzyme is originally synthesized as a homodimeric polypeptide that is
subsequently cleaved to form a heterotetramer composed of 57 and 46 kDa
subunits. A polyclonal antibody raised to the recombinant enzyme was shown
to immunoprecipitate the alpha-mannosidase from T.cruzi cell extracts and
will be used in future immunolocalization studies.
相似文献
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Kouadio Ibrahime Sinan Gokhan Zengin Antonio Fiorentino Brigida D'Abrosca Gunes Ak Devina Lobine Ouattara Katinan Etienne Anwar Hussein Subratty Mohamad Fawzi Mahomoodally 《化学与生物多样性》2021,18(10):e2100371
Spermacoce verticillata (L.) G. Mey. is commonly used in the folk medicine by various cultures to manage common diseases. Herein, the chemical and biological profiles of S. verticillata were studied in order to provide a comprehensive characterization of bioactive compounds and also to highlight the therapeutic properties. The in vitro antioxidant activity using free-radical scavenging, phosphomolybdenum, ferrous-ion chelating and reducing power assays, and the inhibitory activity against key enzymes such as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), tyrosinase, α-amylase and α-glucosidase of S. verticillata extracts (dichloromethane, ethyl acetate, methanol and water) were investigated. The highest total phenolic and flavonoid content were observed in the methanolic and aqueous extracts. Exhaustive 2DNMR investigation has revealed the presence of rutin, ursolic and oleanoic acids. The methanolic extract, followed by aqueous extract have showed remarkable free radical quenching and reducing ability, while the dichloromethane extract was the best source of metal chelators. The tested extracts showed notable inhibitory activity against cholinesterases (AChE: 1.63–4.99 mg GALAE/g extract and BChE: 12.40–15.48 mg GALAE/g extract) and tyrosinase (60.85–159.64 mg KAE/g extract). No inhibitory activity was displayed by ethyl acetate and aqueous extracts against BChE and tyrosinase, respectively. All the tested extracts showed modest α-amylase inhibitory activity, while only the ethyl acetate and aqueous extracts were potent against α-glycosidase. This study further validates the use of S. verticillata in the traditional medicine, while advocating for further investigation for phytomedicine development. 相似文献
177.
C.K. Attchelouwa C.A. Kouakou-Kouamé L. Ouattara T.L.S. Amoikon F.K. N’guessan S. Marcotte M. Charmel M.K. Djè 《Letters in applied microbiology》2022,75(1):135-144
In this study, we aimed to analyse the spoilage potential of the isolated yeast, LAB and AAB species. Thus, 11 strains were inoculated at 0·3% (v/v) into a sterile filtered tchapalo and stored for 3 days at ambient temperature (27–30°C). All the tested strains grew well or remained stable except for Limosilactobacillus fermentum and Pediococcus acidilactici, which decreased throughout the storage time. A significant decrease of total soluble solids was observed only for Saccharomyces cerevisiae (from 7·8 to 5·8 °Brix) and Meyerozyma guilliermondii (from 7·8 to 5·5 °Brix). The tchapalo samples inoculated with the LAB strains Weissella paramesenteroides, P. acidilactici, L. fermentum and the yeast strain Candida tropicalis were judged similar to the control by the panellists. However, the strains of Lacticaseibacillus paracasei and Latilactobacillus curvatus (LAB), S. cerevisiae, M. guilliermondii and Kluyveromyces marxianus (yeasts) and Acetobacter pasteurianus and A. cerevisiae (AAB) induced the spoilage of the tchapalo appearance, smell and/or taste. In the spoiled tchapalo quantitative and qualitative modification of some volatile compounds (VOCs), such as lilac aldehyde, ethyl acetate, ethyl hexanoate, ethyl octanoate and phenethyl acetate, were observed. These results provide information about the microorganisms that need to be removed to extend the shelf life of tchapalo. 相似文献
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M Morgan Conn Joe Kappock Dale Drueckhammer Richard Cammack Dennis Hall Tony Cass Jon D Stewart Graham RL Cousins Jeremy KM Sanders Sabine Flitsch Philip AS Lowden Richard Newman 《Current opinion in chemical biology》1999,3(6):631
A selection of interesting papers that were published in the two months before our press date in major journals most likely to report significant results in chemical biology. 相似文献