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排序方式: 共有87条查询结果,搜索用时 15 毫秒
1.
Anonymous nuclear DNA markers in the American oyster and their implications for the heterozygote deficiency phenomenon in marine bivalves 总被引:4,自引:0,他引:4
A puzzling population-genetic phenomenon widely reported in allozyme
surveys of marine bivalves is the occurrence of heterozygote deficits
relative to Hardy-Weinberg expectations. Possible explanations for this
pattern are categorized with respect to whether the effects should be
confined to protein-level assays or are genomically pervasive and expected
to be registered in both protein- and DNA-level assays. Anonymous nuclear
DNA markers from the American oyster were employed to reexamine the
phenomenon. In assays based on the polymerase chain reaction (PCR), two
DNA-level processes were encountered that can lead to artifactual genotypic
scorings: (a) differential amplification of alleles at a target locus and
(b) amplification from multiple paralogous loci. We describe symptoms of
these complications and prescribe methods that should generally help to
ameliorate them. When artifactual scorings at two anonymous DNA loci in the
American oyster were corrected, Hardy-Weinberg deviations registered in
preliminary population assays decreased to nonsignificant values.
Implications of these findings for the heterozygote-deficit phenomenon in
marine bivalves, and for the general development and use of PCR-based
assays, are discussed.
相似文献
2.
Marta Clariano Vanda Marques João Vaz Salma Awam Marta B. Afonso Maria Jesus Perry Cecília MP Rodrigues 《化学与生物多样性》2023,20(3):e202300222
Curcumin has a plethora of biological properties, making this compound potentially effective in the treatment of several diseases, including cancer. However, curcumin clinical use is compromised by its poor pharmacokinetics, being crucial to find novel analogs with better pharmacokinetic and pharmacological properties. Here, we aimed to evaluate the stability, bioavailability and pharmacokinetic profiles of monocarbonyl analogs of curcumin. A small library of monocarbonyl analogs of curcumin 1a–q was synthesized. Lipophilicity and stability in physiological conditions were both assessed by HPLC-UV, while two different methods assessed the electrophilic character of each compound monitored by NMR and by UV-spectroscopy. The potential therapeutic effect of the analogs 1a–q was evaluated in human colon carcinoma cells and toxicity in immortalized hepatocytes. Our results showed that the curcumin analog 1e is a promising agent against colorectal cancer, with improved stability and efficacy/safety profile. 相似文献
3.
4.
Water hyacinth Eichhornia crassipes is considered the most damaging aquatic weed in the world. However, few studies have quantified the impact of this weed economically and ecologically, and even fewer studies have quantified the benefits of its control. This paper focuses on water loss saving as the benefit derived from biological control of this plant between 1990 and 2013 at New Year’s Dam, Alicedale, Eastern Cape, South Africa. Estimates of water loss due to evapotranspiration from water hyacinth vary significantly; therefore, the study used three different rates, high, medium and low. A conservative raw agriculture value of R 0.26 per m3 was used to calculate the benefits derived by the water saved. The present benefit and cost values were determined using 10% and 5% discount rates. The benefit/cost ratio at the low evapotranspiration rate was less than one, implying that biological control was not economically viable but, at the higher evapotranspiration rates, the return justified the costs of biological control. However, at the marginal value product of water, the inclusion of the costs of damage to infrastructure, or the adverse effects of water hyacinth on biodiversity, would justify the use of biological control, even at the low transpiration rate. 相似文献
5.
D. Penduka K. A. Basson B. Mayekiso L. Buwa I. A. Okoh 《Applied Biochemistry and Microbiology》2014,50(3):297-305
Adsorption chromatography was used to separate the bioactive constituents of the crude n-hexane extract of Garcinia kola seeds. The silica gel 60 column fractions were eluted using the solvent combination of benzene:ethanol:ammonium hydroxide (BEA) in the ratio combination of 36:4:0.4 v/v. The fractions were tested for anti-Listeria activities by determining their MIC50, MIC90 or MIC against 4 Listeria isolates. The fractions were labelled BEA1 to BEA5 and 3 out of the 5 fractions eluted were active against the test Listeria species with MIC’s ranging from MIC 0.157 mg/mL to MIC50 0.625 mg/mL. The most active fractions, BEA2 and BEA3, were subjected to gas chromatography coupled to mass spectrometry (GC-MS) to identify their composition. Fraction BEA2 constituted of 18 compounds mostly sterols and the BEA3 fraction contained 27 compounds with the most abundant compounds being fatty acids derivatives. The BEA2 fraction’s interactions with antibiotics proved to be 100% synergistic with ciprofloxacin and ampicillin whilst it exhibited 50% additivity and 50% synergism with penicillin G. However, all the interactions of the BEA2 fraction with each of the conventional antibiotics used were synergistic against the human listeriosis causative bacteria Listeria monocytogenes. 相似文献
6.
K. Okaiyeto U. U. Nwodo L. V. Mabinya A. I. Okoh 《Applied Biochemistry and Microbiology》2014,50(6):601-608
Bioflocculants are safe, biodegradable and environmentally friendly biopolymeric materials. These merits portend it as preferred alternative to inorganic and organic synthetic polymeric flocculants. The culture conditions optimal for the production of bioflocculant by Micrococcus sp. Leo with subsequent evaluation of the properties of the produced compound were investigated. Optimum culture conditions for bioflocculant production included 2% (vol/vol) inoculum size, incubation temperature of 28°C, agitation speed of 160 rpm and initial pH of 4.0. Glucose and (NH4)2SO4 and Al3+ were the best as sole carbon, nitrogen and cation sources, respectively. The purified bioflocculant flocculated kaolin suspension optimally at a dosage of 0.2 mg/mL following jar test, and flocculating activity of about 70% was retained after heat treatment of 100°C. Chemical analysis showed that the bioflocculant was composed of 28.4% polysaccharide, 2.6% protein and 9.7%. uronic acid. Thermogravimetric analysis demonstrated that the bioflocculant could not decompose completely at 400°C. FTIR spectra revealed the presence of hydroxyl, carboxyl and amino groups as the main functional groups. The bioflocculant produced by Micrococcus sp. Leo appears to hold promise as an alternative to conventional flocculants commonly used in water/wastewater treatment. 相似文献
7.
We assessed the prevalence of free-living and plankton-associated Listeria species in the final effluents of a South African wastewater treatment facility and its receiving watershed between August 2007 and July 2008 as well as the antibiotic susceptibilities of effluent isolates. The physicochemical quality of the raw sewage and treated effluents was also determined. Free-living Listeria were more prevalent (96%), compared to plankton-associated Listeria species (58–67%). Listeria pathogens were sensitive to 11 (55%) of the 20 tested antibiotics, and showed varying (7–71%) levels of resistance to eight antibiotics. Turbidity, COD, NO3, PO4 and Listeria density fell short of recommended standards after treatment; while pH, temperature, TDS, DO and NO2 were compliant with target quality after treatment. We conclude that final effluents of wastewater treatment plants are potential sources of Listeria pathogens in the aquatic milieu of South Africa. 相似文献
8.
Background
To evaluate the antibiogram and antibiotic resistance genes of some Vibrio strains isolated from wastewater final effluents in a rural community of South Africa. V. vulnificus (18), V. metschnikovii (3), V. fluvialis (19) and V. parahaemolyticus (12) strains were isolated from final effluents of a wastewater treatment plant (WWTP) located in a rural community of South Africa. The disk diffusion method was used for the characterization of the antibiogram of the isolates. Polymerase chain reaction (PCR) was employed to evaluate the presence of established antibiotic resistance genes using specific primer sets. 相似文献9.
Jennifer MP Woo Zhuofeng Lin Mohamad Navab Casey Van Dyck Yvette Trejo-Lopez Krystal MT Woo Hongyun Li Lawrence W Castellani Xuping Wang Noriko Iikuni Ornella J Rullo Hui Wu Antonio La Cava Alan M Fogelman Aldons J Lusis Betty P Tsao 《Arthritis research & therapy》2010,12(3):R93
Introduction
The purpose of this study was to evaluate the effects of L-4F, an apolipoprotein A-1 mimetic peptide, alone or with pravastatin, in apoE-/-Fas-/-C57BL/6 mice that spontaneously develop immunoglobulin G (IgG) autoantibodies, glomerulonephritis, osteopenia, and atherosclerotic lesions on a normal chow diet.Methods
Female mice, starting at eight to nine weeks of age, were treated for 27 weeks with 1) pravastatin, 2) L-4F, 3) L-4F plus pravastatin, or 4) vehicle control, followed by disease phenotype assessment.Results
In preliminary studies, dysfunctional, proinflammatory high-density lipoproteins (piHDL) were decreased six hours after a single L-4F, but not scrambled L-4F, injection in eight- to nine-week old mice. After 35 weeks, L-4F-treated mice, in the absence/presence of pravastatin, had significantly smaller lymph nodes and glomerular tufts (PL, LP < 0.05), lower serum levels of IgG antibodies to double stranded DNA (dsDNA) (PL < 0.05) and oxidized phospholipids (oxPLs) (PL, LP < 0.005), and elevated total and vertebral bone mineral density (PL, LP < 0.01) compared to vehicle controls. Although all treatment groups presented larger aortic root lesions compared to vehicle controls, enlarged atheromas in combination treatment mice had significantly less infiltrated CD68+ macrophages (PLP < 0.01), significantly increased mean α-actin stained area (PLP < 0.05), and significantly lower levels of circulating markers for atherosclerosis progression, CCL19 (PL, LP < 0.0005) and VCAM-1 (PL < 0.0002).Conclusions
L-4F treatment, alone or with pravastatin, significantly reduced IgG anti-dsDNA and IgG anti-oxPLs, proteinuria, glomerulonephritis, and osteopenia in a murine lupus model of accelerated atherosclerosis. Despite enlarged aortic lesions, increased smooth muscle content, decreased macrophage infiltration, and decreased pro-atherogenic chemokines in L-4F plus pravastatin treated mice suggest protective mechanisms not only on lupus-like disease, but also on potential plaque remodeling in a murine model of systemic lupus erythematosus (SLE) and accelerated atherosclerosis. 相似文献10.