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21.
Norman E. Whitten Jr. 《American anthropologist》2003,105(3):677-678
African Roots/American Cultures: Africa in the Creation of the Americas. Sheila S. Walker. ed. Lanham, MD: Rowman and Littlefield Publishers, Inc., 2001. 400 pp. 相似文献
22.
Koehler S Cabral JS Whitten WM Williams NH Singer RB Neubig KM Guerra M Souza AP Amaral Mdo C 《Annals of botany》2008,102(4):491-507
Background and Aims
Species'' boundaries applied within Christensonella have varied due to the continuous pattern of variation and mosaic distribution of diagnostic characters. The main goals of this study were to revise the species'' delimitation and propose a more stable classification for this genus. In order to achieve these aims phylogenetic relationships were inferred using DNA sequence data and cytological diversity within Christensonella was examined based on chromosome counts and heterochromatin patterns. The results presented describe sets of diagnostic morphological characters that can be used for species'' identification.Methods
Phylogenetic studies were based on sequence data of nuclear and plastid regions, analysed using maximum parsimony and maximum likelihood criteria. Cytogenetic observations of mitotic cells were conducted using CMA and DAPI fluorochromes.Key Results
Six of 21 currently accepted species were recovered. The results also support recognition of the ‘C. pumila’ clade as a single species. Molecular phylogenetic relationships within the ‘C. acicularis–C. madida’ and ‘C. ferdinandiana–C. neowiedii’ species'' complexes were not resolved and require further study. Deeper relationships were incongruent between plastid and nuclear trees, but with no strong bootstrap support for either, except for the position of C. vernicosa. Cytogenetic data indicated chromosome numbers of 2n = 36, 38 and 76, and with substantial variation in the presence and location of CMA/DAPI heterochromatin bands.Conclusions
The recognition of ten species of Christensonella is proposed according to the molecular and cytogenetic patterns observed. In addition, diagnostic morphological characters are presented for each recognized species. Banding patterns and chromosome counts suggest the occurrence of centric fusion/fission events, especially for C. ferdinandiana. The results suggest that 2n = 36 karyotypes evolved from 2n = 38 through descendent dysploidy. Patterns of heterochromatin distribution and other karyotypic data proved to be a valuable source of information to understand evolutionary patterns within Maxillariinae orchids.Key words: Chromosome number, Christensonella, Cymbidieae, cytotaxonomy, fluorochrome staining, Maxillaria, Maxillariinae, molecular phylogenetics, species delimitation 相似文献23.
Sequences of the nuclear ribosomal internal transcribed spacer regions 1 & 2 (nrDNA ITS) including the intervening 5.8S region
were analyzed cladistically for 43 individuals of 35 species ofScaphyglottis s.l. plus two outgroup taxa. Low levels of sequence divergence do not allow estimation of relationships among most clades,
but the analyses indicate that four segregate genera (Hexisea Lindl.,Reichenbachanthus Barb. Rodr.,Hexadesmia Brogn., andPlatyglottis coriacea L.O. Williams) are embedded within a broad paraphyleticScaphyglottis. This broadly definedScaphyglottis sensu Dressler is characterized within Laeliinae by the usual presence of superposed growth habit and the presence of a column
foot. In order to accommodate species formerly placed inPlatyglottis andReichenbachanthus, three new combinations are made inScaphyglottis:Scaphyglottis brasiliensis (Schltr.) Dressler,S. coriacea (L. O. Williams) Dressier, andS. emarginata (Garay) Dressler. 相似文献
24.
A correlation between BCL-2 modifying factor,p53 and livin gene expressions in cancer colon patients
Eman AE. Badr Mohamed FA. Assar Abdel Monem A. Eltorgoman Azza Zaghlol Labeeb Gehad A. Breaka Enas A. Elkhouly 《Biochemistry and Biophysics Reports》2020
Accumulating evidence has revealed that livin gene and BCL-2 modifying factor (BMF) gene are closely associated with the initiation and progression of colon carcinoma by activating or suppressing multiple malignant processes. Those genes that can detect colon - cancer are a promising approach for cancer screening and diagnosis. This study aimed to evaluate correlation between livin, BMF and p53 genes expression in colon cancer tissues of patients included in the study, and their relationship with clinicopathological features and survival outcome in those patients. In this study, 50 pathologically diagnosed early cancer colon patients included and their tissue biopsy with 50 matched adjacent normal tissue, and 50 adenoma tissue specimens were analyzed for livin gene and BMF gene expressions using real time PCR. The relationship of those genes expressions with clinicopathological features, tumor markers, Time to Progression and overall survival for those patients were correlated in cancer colon group. In this study, there was a significant a reciprocal relationship between over expression of livin gene and down regulation of BMF and p53 genes in colon cancer cells. Livin mRNA was significantly higher, while BMF and p53 mRNA were significantly lower in colorectal cancer tissue compared to benign and normal colon tissue specimens (P < 0.001), however, this finding was absent between colon adenomas and normal mucosa. There was a significant association between up regulation of livin and down regulation of BMF and p53 expressions with more aggressive tumor (advanced TNM stage), rapid progression with metastasis and decreased overall survival in cancer colon patients, hence these genes can serve as significant prognostic markers of poor outcome in colon cancer patients. This work highlights the role of livin, BMF and p53 genes in colorectal tumorigenesis and the applicability of using those genes as a diagnostic and prognostic markers in patients with colon carcinoma and as a good target for cancer colon treatment in the future. 相似文献
25.
26.
Whitten MM Tew IF Lee BL Ratcliffe NA 《Journal of immunology (Baltimore, Md. : 1950)》2004,172(4):2177-2185
Lipoproteins and molecules for pattern recognition are centrally important in the innate immune response of both vertebrates and invertebrates. Mammalian apolipoproteins such as apolipoprotein E (apoE) are involved in LPS detoxification, phagocytosis, and possibly pattern recognition. The multifunctional insect protein, apolipophorin III (apoLp-III), is homologous to apoE. In this study we describe novel roles for apoLp-III in pattern recognition and multicellular encapsulation reactions in the innate immune response, which may be of direct relevance to mammalian systems. It is known that apoLp-III stimulates antimicrobial peptide production in insect blood, enhances phagocytosis by insect blood cells (hemocytes), and binds and detoxifies LPS and lipoteichoic acid. In the present study we show that apoLp-III from the greater wax moth, Galleria mellonella, also binds to fungal conidia and beta-1,3-glucan and therefore may act as a pattern recognition molecule for multiple microbial and parasitic invaders. This protein also stimulates increases in cellular encapsulation of nonself particles by the blood cells and exerts shorter term, time-dependent, modulatory effects on cell attachment and spreading. All these responses are dose dependent, occur within physiological levels, and, with the notable exception of beta-glucan binding, are only observed with the lipid-associated form of apoLp-III. Preliminary studies also established a beneficial role for apoLp-III in the in vivo response to an entomopathogenic fungus. These data suggest a wide range of immune functions for a multiple specificity pattern recognition molecule and may provide a useful model for identifying further potential roles for homologous proteins in mammalian immunology, particularly in terms of fungal infections, pneumoconiosis, and granulomatous reactions. 相似文献
27.
Reema Zeineldin Menake E Piyasena Troy S Bergstedt Larry A Sklar David Whitten Gabriel P Lopez 《Cytometry. Part A》2006,69(5):335-341
BACKGROUND: Fluorescent conjugated polymers display high fluorescence quantum yields and enhanced sensitivity to quenching (superquenching) by oppositely charged quenchers through energy or electron transfer. Fluorescent polymers and their quenchers are used in bead-based biosensor applications where the polymers are coated on particles. In this work, we investigate a detection method that utilizes superquenching on microspheres, which can be used for flow cytometric assays. METHODS: Microspheres were coated with the fluorescent cationic polyelectrolyte poly(p-phenylene-ethynylene) (PPE), and its superquenching by 9,10-anthraquinone-2,6-disulfonic acid (AQS) was examined by fluorometric methods in presence and in absence of a barrier to superquenching in the form of an anionic lipid bilayer. RESULTS: Flow cytometry detected superquenching of PPE on microspheres (MS-PPE) by AQS where high levels of reduction in fluorescence were observed. Adding different concentrations of AQS to MS-PPE yielded a Stern-Volmer quenching constant of 0.8x10(6) M-1. While forming an anionic lipid bilayer around the MS-PPE acted as a barrier to superquenching by AQS, disrupting the lipid bilayer allowed superquenching to take place. CONCLUSIONS: The sensitivity of flow cytometry in detecting fluorescence of microspheres and the amplified quenching sensitivity of fluorescent conjugated polymers both offer advantages over other fluorometric methods and conventional quenching detection. This study used superquenching of fluorescent polymers as a new tool in flow cytometry, thus combining the advantages offered by both method and detector. In addition, we employed the formation and the disruption of a supported lipid bilayer in mediating superquenching to offer new biosensing applications. 相似文献
28.
Recent advances in NMR methodology have enabled the structural analysis of proteins at temperatures far below the freezing point of water, thus opening a window to the cold denaturation process. Although the phenomenon of cold denaturation has been known since the mid-1970s, the freezing point of water has prevented detailed and structurally resolved studies without application of additional significant perturbations of the protein ensemble. As a result, the cold-denatured state and the process of cold denaturation have gone largely unstudied. Here, the structural and thermodynamic basis of cold denaturation is explored with emphasis placed on the insights that are uniquely ascertained from low-temperature studies. It is shown that the noncooperative cold-induced unfolding of protein results in the population of partially folded states that cannot be accessed by other techniques. The structurally resolved view of the cold denaturation process therefore can provide direct access to the cooperative substructures within the protein molecule and provide an unprecedented structurally resolved picture of the states that comprise the native state ensemble. 相似文献
29.
30.
Anthony J. Whitten 《Animal behaviour》1982,30(1):182-198
A home range is a reservoir of resources which are distributed throughout its area and joined by pathways. These resources are used for different activities and at different times of day and while ‘space-time systems’ have been described for a few terrestrial mammals, no previous study has attempted a similar analysis for an arboreal mammal. Kloss gibbons were studied for two years on Siberut Island, Indonesia, and one group was habituated to an observer. The ranging patterns of this group are analysed in two, three and four dimensions with respect to the types of forest in which the animals lived. Finally, differences between the results of this and previous studies of Kloss gibbons are discussed and it is suggested that a home range can be more permanent than the animals within it. 相似文献