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1.
H. Ben Slimen F. Suchentrunk A. Memmi H. Sert U. Kryger P.C. Alves A. Ben Ammar Elgaaied 《Journal of Zoological Systematics and Evolutionary Research》2006,44(1):88-99
Systematics and taxonomy of hares of the genus Lepus (Lagomorpha) are under contentious debate, and phylogenetic relationships among many taxa are not well understood. Here we study genetic differentiation and evolutionary relationships among North African hares, currently considered subspecies of Lepus capensis , cape hares ( L. capensis ) from the Cape province in South Africa, and brown hares ( L. europeaus ) from Europe and Anatolia, using maternally (mtDNA) and biparentally (allozymes) inherited markers. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of a c. 1.8 kb long segment of the mitochondrial control region using eight hexanucleotide-recognizing restriction endonucleases yielded 28 haplotypes, and horizontal starch gel electrophoresis of proteins encoded by 25 structural gene loci revealed 52 alleles at 18 polymorphic loci. Diverse phylogenetic analyses (neighbor joining dendrogram, median joining network, multidimensional scaling of pairwise distances, AMOVA, F -statistics, hierarchical F -statistics) of genetic variants revealed marked substructuring of mtDNA into three phylogeographic groups, namely an African, a central European, and an Anatolian, but a somewhat less pronounced overall differentiation of the nuclear genome, despite a relatively high number of population-specific (private) alleles. However, all our results are not incongruent with Petter's (1959: Mammalia 23 , 41; 1961: Z. f. Säugetierkunde 26 , 30; 1972 : Société Des Sciences Naturelles et Physiques du Maroc 52 , 122) hypothesis that North African hares generally belong to L. capensis and that brown hares should be included in this species as well. 相似文献
2.
E. D. Ammar 《Journal of Phytopathology》1994,141(2):153-158
Samples of maize leaves naturally infected with maize streak virus (MSV) from Malawi and South Africa, as well as sugarcane leaves naturally infected with sugarcane streak virus (SSV) from Egypt, were examined by light (LM) and transmission electron, microscopy (TEM). Intranuclear inclusions, detectable by both methods, were found mainly in mesophyll and bundle sheath cells, and less frequently in vascular parenchyma and immature phloem cells. At higher TEM magnifications, these inclusions consisted, of crystalline or noncrystalline aggregates of isometric geminivirus–like particles (VLP) that occurred either singly or in geminate arrays. Cytopathological changes in these cells were confined to the nuclei, which were usually larger than normal, with peripheral chromatin and nucleoli. The nuclear envelope of some inclusion–containing nuclei was ruptured, and occasionally a crystal of VLP was found in the cytoplasm of cells in which no intact nuclei were detected. No differences in cytopathology were found between MSV and SSV, or between the two MSV isolates examined. 相似文献
3.
J. Berreur-Bonnenfant M. Ammar A. Dubreuil H. Kiefer G Diogene P. Metezeau S. Puiseux-Dao 《Cell biology and toxicology》1994,10(5-6):423-427
Maitotoxin (MTX) induces an increase of [Ca2+]i and of phosphoinositide breakdown in various cell types. The [Ca2+]i increase followed with fluorescent probes on cell suspensions has been described as slow and lasting, in contrast to the signal induced by calcium ionophores such as ionomycin. MTX effects have been studied on two fibroblastic cell lines, BHK21 C13 and FR 3T3, synchronized by serum deprivation treatment performed in an isoleucine-free medium for BHK21 C13 cells. In BHK21 C13 cells, flow cytometry analysis showed that two stages, G1/S and G2/M, were particularly susceptible to MTX treatment. Scanning laser cytometry demonstrated that calcium response of FR 3T3 fibroblasts followed with Indo-1 varied during the cell division cycle. The [Ca2+]i increase was almost always vertical, but its delay after MTX addition lasted from zero (S and G2/M transition) to 10–20 min (G1) or more (G2). No [Ca2+]i change could be detected during mitosis. The [Ca2+]i response at the S phase was biphasic. These observations suggest that (1) the lasting response described in the literature represents a global cell population effect, and (2) cells are more sensitive to MTX at specific stages of the cell division cycle, which could correspond to periods when calcium signals have been detected in different cell types.Abbreviations MTX
maitotoxin
- [Ca2+]i
intracellular calcium concentration
- IP3
inositol triphosphate 相似文献
4.
Survival and growth of Escherichia coli O157:H7 in ground, roasted beef as affected by pH, acidulants, and temperature. 总被引:12,自引:9,他引:3 下载免费PDF全文
A study was undertaken to determine the fate of Escherichia coli O157:H7 in ground, roasted beef as influenced by the combined effects of pH, acidulants, temperature, and time. There was essentially no change in the viable population of E. coli O157:H7 when beef salads (pH 5.40 to 6.07) containing up to 40% mayonnaise were incubated at 5 degrees C for up to 72 h. At 21 and 30 degrees C, significant (P < or = 0.05) increases in populations of the organism occurred in salads containing 16 to 32% mayonnaise (pH 5.94 to 5.55) between 10 and 24 h of incubation. Death was more rapid as the pH of acidified beef slurries incubated at 5 degrees C was decreased from 5.98 to 4.70. E. coli O157:H7 grew in control slurries (pH 5.98) and in slurries containing citric and lactic acids (pHs 5.00 and 5.40) incubated at 21 degrees C for 24 h; decreases occurred in slurries acidified to pHs 4.70, 5.00, and 5.40 with acetic acid or pH 4.70 with citric or lactic acid. At 30 degrees C, populations decreased in slurries acidified to pHs 4.70 and 5.00 with acetic acid. Citric and lactic acids failed to prevent significant increases in populations in slurries at pH 4.70 to 5.40 between 10 and 24 h of incubation. The order of effectiveness of acidulants in inhibiting growth was acetic acid > lactic acid > or = citric acid. The same order was observed for inactivation of E. coli O157:H7 in acidified (pH 5.00) beef slurry heated at 54 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
5.
Remon M. Zaki Adel M. Kamal El-Dean Radwan Shaban M. Ammar Mahmoud A. 《Russian Journal of Bioorganic Chemistry》2020,46(1):85-96
Russian Journal of Bioorganic Chemistry - We describe a simple method to synthesize novel 4-cyano-1-morpholin-4-yl-6,7-dihydro-5H-cyclopenta[c]pyridine-3-thione by the reaction of... 相似文献
6.
Gaci Meriem Benhizia Yacine Dems Mohamed AbdEsselem Boukaous Leyla Benguedouar Ammar Hynes Michael Francis 《Plant and Soil》2021,461(1-2):369-388
Plant and Soil - The nitrogen-fixing symbiosis fixation between legumes and Rhizobium helps the plant to survive and to compete effectively on nitrogen poor soils. The soil environment attached to... 相似文献
7.
Imad Mennai Esma Lamera Nabila Slougui Brahim Benaicha Salim Gasmi Zakaria Samai Naima Rahmouni Chawki Bensouici Diana C. G. A. Pinto 《化学与生物多样性》2021,18(9):e2100278
This work aimed to investigate, for the first time, the chemical composition, antioxidant, antiparasitic, cytotoxicity, and antimicrobial activities of the aromatic plant Limonium oleifolium Mill. essential oil (EO) and organic extracts. L. oleifolium aerial parts essential oil was analyzed by GC-FID and GC-MS, and 46 constituents representing 98.25±1.12 % of the oil were identified. γ-Muurolene (10.81±0.07 %), cis-caryophyllene (7.71±0.06 %), o-cymene (7.07±0.01 %) and α-copaene (5.02±0.05 %) were the essential oil main compounds. The antioxidant activity of L. oleifolium EO and organic extracts (MeOH, CHCl3, AcOEt, BuOH) was explored using 2,2-diphenyl-1-picrylhydrazyl (DPPH), ABTS, β-carotene/linoleic acid, cupric reducing antioxidant capacity (CUPRAC), and ferric reducing power assays. The results showed that L. oleifolium EO exhibit antioxidant capacity (IC50=17.40±1.32 μg/mL for DPPH assay, IC50=29.82±1.08 μg/mL for β-carotene assay, IC50=25.23±1.01 μg/mL for ABTS assay, IC50=9.11±0.08 μg/mL for CUPRAC assay and IC50=19.41±2.06 mg/mL for reducing power assay). Additionally, the EO showed significant activity against trophozoite form of Acanthamoeba castellanii (IC50=7.48±0.41 μg/mL) and promastigote form of Leishmania amazonensis (IC50=19.36±1.06 μg/mL) and low cytotoxicity on murine macrophages (LC50 90.23±1.09 μg/mL), as well as good antimicrobial activity against Staphylococcus aureus, Escherichia coli, Klebsiella oxytoca, and Pseudomonas aeruginosa. These results suggest that L. oleifolium essential oil is a valuable source of bioactive compounds presenting antioxidant, antiparasitic, and antimicrobial activities. Furthermore, it is considered nontoxic. 相似文献
8.
A. Singh M. P. Pandey A. K. Singh R. E. Knox K. Ammar J. M. Clarke F. R. Clarke R. P. Singh C. J. Pozniak R. M. DePauw B. D. McCallum R. D. Cuthbert H. S. Randhawa T. G. Fetch Jr. 《Molecular breeding : new strategies in plant improvement》2013,31(2):405-418
Leaf rust (Puccinia triticina Eriks.), stripe rust (Puccinia striiformis f. tritici Eriks.) and stem rust (Puccinia graminis f. sp. tritici) cause major production losses in durum wheat (Triticum turgidum L. var. durum). The objective of this research was to identify and map leaf, stripe and stem rust resistance loci from the French cultivar Sachem and Canadian cultivar Strongfield. A doubled haploid population from Sachem/Strongfield and parents were phenotyped for seedling reaction to leaf rust races BBG/BN and BBG/BP and adult plant response was determined in three field rust nurseries near El Batan, Obregon and Toluca, Mexico. Stripe rust response was recorded in 2009 and 2011 nurseries near Toluca and near Njoro, Kenya in 2010. Response to stem rust was recorded in field nurseries near Njoro, Kenya, in 2010 and 2011. Sachem was resistant to leaf, stripe and stem rust. A major leaf rust quantitative trait locus (QTL) was identified on chromosome 7B at Xgwm146 in Sachem. In the same region on 7B, a stripe rust QTL was identified in Strongfield. Leaf and stripe rust QTL around DArT marker wPt3451 were identified on chromosome 1B. On chromosome 2B, a significant leaf rust QTL was detected conferred by Strongfield, and at the same QTL, a Yr gene derived from Sachem conferred resistance. Significant stem rust resistance QTL were detected on chromosome 4B. Consistent interactions among loci for resistance to each rust type across nurseries were detected, especially for leaf rust QTL on 7B. Sachem and Strongfield offer useful sources of rust resistance genes for durum rust breeding. 相似文献
9.
The Asian citrus psyllid (ACP), Diaphorina citri (Hemiptera: Psyllidae) is the primary vector of the bacterium causing citrus huanglongbing (citrus greening), the most serious disease of citrus worldwide. Psyllids and other hemipterans produce large amounts of honeydew, which has been used previously as an indicator of phloem sap composition and insect feeding or metabolism. Behavioral, ultrastructural and chemical studies on ACP, its honeydew and waxy secretions showed important differences between nymphs, males and females, and suggested some mechanisms by which the psyllids, especially nymphs and adult females, can minimize their contamination with honeydew excretions. The anal opening in ACP, near the posterior end of the abdomen, is on the ventral side in nymphs and on the dorsal side in adult males and females. Video recordings showed that adult males produce clear sticky droplets of honeydew gently deposited behind their body on the leaf surface, whereas adult females produce whitish honeydew pellets powerfully propelled away from the female body, probably to get their excretions away from eggs and newly hatched nymphs. ACP nymphs produce long ribbons or tubes of honeydew that frequently stay attached to the exuviae after molting, or drop when feeding on the lower side of citrus leaves. Furthermore, honeydew excretions of both nymphs and adult females are covered with a thin layer of whitish waxy material ultrastructurally composed of a convoluted network of long fine filaments or ribbons. This material is extruded from intricate arrays of wax pores in the circumanal ring (around the anus) that is found in nymphs and females but not in males of ACP or other psyllid species. Infrared microscopy and mass spectroscopy revealed that, in addition to various sugars, honeydew excretions of ACP nymphs and females are covered with a thin layer of wax similar in profile to ester waxes. 相似文献
10.