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排序方式: 共有433条查询结果,搜索用时 31 毫秒
91.
Stearoyl-CoA desaturase (SCD) catalyzes the synthesis of conjugated linoleic acid (CLA) and mono-unsaturated fatty acids (MUFA) from their saturated counterparts in the mammary gland and adipose tissue of ruminant animals. We hypothesize that single nucleotide polymorphisms (SNPs) in the SCD gene account for some of the differences in SCD activity, and consequently for some of the variations in CLA and MUFA content of milk fat between Holsteins and Jersey cows and within these two breeds. We analyzed the open reading frame of the SCD gene of 44 Holsteins and 48 Jerseys for SNPs by sequencing. Three SNPs: 702A --> G, 762T --> C and 878C --> T were identified in both breeds and a further SNP, 435G --> A, was unique to Holsteins. The SNPs characterized four different genetic variants in Holsteins: A (G(435)A(702)T(762)C(878)), A1 (A(435)A(702)T(762)C(878)), B (G(435)G(702)C(762)T(878)) and B1 (A(435)G(702)C(762)T(878)), with only variants A and B in Jerseys. SNP 878C --> T resulted in a non-synonymous codon change while the rest resulted in synonymous codon changes giving rise to two protein variants, A having alanine and B having valine. Allele A was the most prevalent in the two breeds. These differences may, therefore, contribute to existing variations in CLA and fat content between and within Canadian Holstein and Jersey cows. 相似文献
92.
Maiken Cavling Arendrup Eleftheria Mavridou Klaus Leth Mortensen Eveline Snelders Niels Frimodt-M?ller Humara Khan Willem J. G. Melchers Paul E. Verweij 《PloS one》2010,5(4)
Four sequential Aspergillus fumigatus isolates from a patient with chronic granulomatous disease (CGD) eventually failing azole-echinocandin combination therapy were investigated. The first two isolates (1 and 2) were susceptible to antifungal azoles, but increased itraconazole, voriconazole and posaconazole MICs were found for the last two isolates (3 and 4). Microsatellite typing showed that the 4 isolates were isogenic, suggesting that resistance had been acquired during azole treatment of the patient. An immunocompromised mouse model confirmed that the in vitro resistance corresponded with treatment failure. Mice challenged with the resistant isolate 4 failed to respond to posaconazole therapy, while those infected by susceptible isolate 2 responded. Posaconazole-anidulafungin combination therapy was effective in mice challenged with isolate 4. No mutations were found in the Cyp51A gene of the four isolates. However, expression experiments of the Cyp51A showed that the expression was increased in the resistant isolates, compared to the azole-susceptible isolates. The microscopic morphology of the four isolates was similar, but a clear alteration in radial growth and a significantly reduced growth rate of the resistant isolates on solid and in broth medium was observed compared to isolates 1 and 2 and to unrelated wild-type controls. In the mouse model the virulence of isolates 3 and 4 was reduced compared to the susceptible ones and to wild-type controls. For the first time, the acquisition of azole resistance despite azole-echinocandin combination therapy is described in a CGD patient and the resistance demonstrated to be directly associated with significant change of virulence. 相似文献
93.
94.
Pelicice Fernando Mayer da Silva Damasceno Luciana de Almeida Ferreira Eveline da Graa Weferson Jnio Agostinho Carlos Srgio Fernandes Rodrigo 《Hydrobiologia》2022,849(2):373-384
Hydrobiologia - In this paper, we investigated composition and trait turnover among fish assemblages in reservoirs distributed across major Brazilian basins, in order to contrast taxonomic and... 相似文献
95.
Evidence based selection of housekeeping genes 总被引:2,自引:0,他引:2
de Jonge HJ Fehrmann RS de Bont ES Hofstra RM Gerbens F Kamps WA de Vries EG van der Zee AG te Meerman GJ ter Elst A 《PloS one》2007,2(9):e898
For accurate and reliable gene expression analysis, normalization of gene expression data against housekeeping genes (reference or internal control genes) is required. It is known that commonly used housekeeping genes (e.g. ACTB, GAPDH, HPRT1, and B2M) vary considerably under different experimental conditions and therefore their use for normalization is limited. We performed a meta-analysis of 13,629 human gene array samples in order to identify the most stable expressed genes. Here we show novel candidate housekeeping genes (e.g. RPS13, RPL27, RPS20 and OAZ1) with enhanced stability among a multitude of different cell types and varying experimental conditions. None of the commonly used housekeeping genes were present in the top 50 of the most stable expressed genes. In addition, using 2,543 diverse mouse gene array samples we were able to confirm the enhanced stability of the candidate novel housekeeping genes in another mammalian species. Therefore, the identified novel candidate housekeeping genes seem to be the most appropriate choice for normalizing gene expression data. 相似文献
96.
Eveline M van den Berg Udo van Dongen Ben Abbas Mark CM van Loosdrecht 《The ISME journal》2015,9(10):2153-2161
Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are competing microbial nitrate-reduction processes. The occurrence of DNRA has been shown to be effected qualitatively by various parameters in the environment. A more quantitative understanding can be obtained using enrichment cultures in a laboratory reactor, yet no successful DNRA enrichment culture has been described. We showed that a stable DNRA-dominated enrichment culture can be obtained in a chemostat system. The enrichment was based on the hypothesis that nitrate limitation is the dominant factor in selecting for DNRA. First, a conventional denitrifying culture was enriched from activated sludge, with acetate and nitrate as substrates. Next, the acetate concentration in the medium was increased to obtain nitrate-limiting conditions. As a result, conversions shifted from denitrification to DNRA. In this selection of a DNRA culture, two important factors were the nitrate limitation and a relatively low dilution rate (0.026 h−1). The culture was a highly enriched population of Deltaproteobacteria most closely related to Geobacter lovleyi, based on 16S rRNA gene sequencing (97% similarity). We established a stable and reproducible cultivation method for the enrichment of DNRA bacteria in a continuously operated reactor system. This enrichment method allows to further investigate the DNRA process and address the factors for competition between DNRA and denitrification, or other N-conversion pathways. 相似文献
97.
Jo De Vrieze Linde Raport Bernard Willems Silke Verbrugge Eveline Volcke Erik Meers Largus T Angenent Nico Boon 《Microbial biotechnology》2015,8(5):776-786
Obtaining a reliable estimation of the methane potential of organic waste streams in anaerobic digestion, for which a biochemical methane potential (BMP) test is often used, is of high importance. Standardization of this BMP test is required to ensure inter-laboratory repeatability and accuracy of the BMP results. Therefore, guidelines were set out; yet, these do not provide sufficient information concerning origin of and the microbial community in the test inoculum. Here, the specific contribution of the methanogenic community on the BMP test results was evaluated. The biomethane potential of four different substrates (molasses, bio-refinery waste, liquid manure and high-rate activated sludge) was determined by means of four different inocula from full-scale anaerobic digestion plants. A significant effect of the selected inoculum on the BMP result was observed for two out of four substrates. This inoculum effect could be attributed to the abundance of methanogens and a potential inhibiting effect in the inoculum itself, demonstrating the importance of inoculum selection for BMP testing. We recommend the application of granular sludge as an inoculum, because of its higher methanogenic abundance and activity, and protection from bulk solutions, compared with other inocula. 相似文献
98.
LS Tavares JV Rettore RM Freitas WF Porto AP Duque Jde L Singulani ON Silva Mde L Detoni EG Vasconcelos SC Dias OL Franco Mde O Santos 《Peptides》2012,37(2):294-300
Antimicrobial peptides (AMPs) are compounds that act in a wide range of physiological defensive mechanisms developed to counteract bacteria, fungi, parasites and viruses. These molecules have become increasingly important as a consequence of remarkable microorganism resistance to common antibiotics. This report shows Escherichia coli expressing the recombinant antimicrobial peptide Pg-AMP1 previously isolated from Psidium guajava seeds. The deduced Pg-AMP1 open reading frame consists in a 168bp long plus methionine also containing a His6 tag, encoding a predicted 62 amino acid residue peptide with related molecular mass calculated to be 6.98kDa as a monomer and 13.96kDa at the dimer form. The recombinant Pg-AMP1 peptide showed inhibitory activity against multiple Gram-negative (E. coli, Klebsiella pneumonia and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus and Staphylococcus epidermides) bacteria. Moreover, theoretical structure analyses were performed in order to understand the functional differences between natural and recombinant Pg-AMP1 forms. Data here reported suggest that Pg-AMP1 is a promising peptide to be used as a biotechnological tool for control of human infectious diseases. 相似文献
99.
100.
Vermeulen CF Grünberg A Peters LA van der Linden-Narain IB Vrede MA Krul EJ Dekker FW Fleuren GJ 《Acta cytologica》2006,50(6):621-626
OBJECTIVE: To determine the prevalence of cytologic abnormalities in cervical smears from women attending the first organized screening program in Suriname and to compare the prevalences in 4 Surinamese ethnicities with different cervical carcinoma incidences. STUDY DESIGN: Cervical scrapes were taken from women with 4 different ethnicities: Maroons, Amerindians, Javanese and Hindustani. Papanicolaou staining and cytologic screening were performed on 807 cervical smears. RESULTS Cervical cytologic abnormalities were seen in 13.4%, of which 8.1% (62 of 764) had atypical changes, 2.6% (20 of 764) had mild and 2.6% (20 of 764) had moderate and severe dysplasia/carcinoma in situ (CIS). The cytologic abnormalities varied between the ethnicities: 42.1% (83 of 197) in the Maroons and 2.3% (4 of 176), 5.0% (9 of 183) and 3.0% (6 of 208) in the Javanese, Amerindians, and Hindustani, respectively. CONCLUSION: The high prevalence of moderate and severe dysplasia/CIS in all ethnicities correlates with the high cervical carcinoma incidence in Suriname. A significantly higher prevalence of mild abnormalities in the Maroons was observed; it did not reflect the relatively low cervical cancer incidence in this ethnicity. However, this can be explained by the possibility that these women have a different sexual lifestyle, leading to a higher prevalence of 相似文献