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81.
Evidence for effect of random genetic drift on G+C content after lateral transfer of fucose pathway genes to Escherichia coli K-12 总被引:4,自引:0,他引:4
The cps cluster of Escherichia coli K-12 comprises genes involved in
synthesis of capsular polysaccharide colanic acid. Part of the E. coli K-12
cps region has been cloned and sequenced and compared to its Salmonella
enterica LT2 counterpart. The cps genes from the two organisms are
homologous; in the case of the LT2 genes, with G+C content of 0.61 and
codons characteristic of high G+C species, it seems clear that they have
been acquired relatively recently by lateral transfer from a high G+C
species. The K-12 form of these cps genes is closely related to those of
LT2 so must derive from the same high G+C species, but it appears to have
transferred much earlier such that random genetic drift has brought P3 (the
corrected G+C content of codon base 3) down from 0.77 to 0.64, more than
halfway to the E. coli average of 0.57. We estimate, using an equation
developed by Sueoka, that the lateral transfer to E. coli took place
approximately 45 million years ago. This is the first report we are aware
of demonstrating the expected adjustment of P3 after lateral transfer
between species with different G+C content DNA.
相似文献
82.
Chan RK Garfein E Gigante PR Liu P Agha RA Mulligan R Orgill DP 《Plastic and reconstructive surgery》2007,120(2):407-11; discussion 412-3
83.
Genes essential for the production of a linear, bacterial (1-->3)-beta-
glucan, curdlan, have been cloned for the first time from Agrobacterium sp.
ATCC31749. The genes occurred in two, nonoverlapping, genomic fragments
that complemented different sets of curdlan( crd )-deficient
transposon-insertion mutations. These were detected as colonies that failed
to stain with aniline blue, a (1-->3)-beta-glucan specific dye. One
fragment carried a biosynthetic gene cluster (locus I) containing the
putative curdlan synthase gene, crdS, and at least two other crd genes. The
second fragment may contain only a single crd gene (locus II).
Determination of the DNA sequence adjacent to several locus I mutations
revealed homology to known sequences only in the cases of crdS mutations.
Complete sequencing of the 1623 bp crdS gene revealed highest similarities
between the predicted CrdS protein (540 amino acids) and glycosyl
transferases with repetitive action patterns. These include bacterial
cellulose synthases (and their homologs), which form
(1-->4)-beta-glucans. No similarity was detected with putative
(1-->3)- beta-glucan synthases from yeasts and filamentous fungi.
Whatever the determinants of the linkage specificity of these beta-glucan
synthases might be, these results raise the possibility that
(1-->3)-beta-glucans and (1-->4)-beta-glucans are formed by related
catalytic polypeptides.
相似文献
84.
Massimiliano D’Imperio Giacomina Brunetti Isabella Gigante Francesco Serio Pietro Santamaria Angela Cardinali Silvia Colucci Fiorenza Minervini 《In vitro cellular & developmental biology. Animal》2017,53(3):217-224
Food industries are increasingly oriented toward new foods to improve nutritional status and/or to combat nutritional deficiency diseases. In this context, silicon biofortification could be an innovative tool for obtaining new foods with possible positive effects on bone mineralization. In this paper, an alternative and quick in vitro approach was applied in order to evaluate the potential health-promoting effects of five silicon-biofortified leafy vegetables (tatsoi, mizuna, purslane, Swiss chard and chicory) on bone mineralization compared with a commercial silicon supplement. The silicon bioaccessibility and bioavailability of the five leafy vegetables (biofortified or not) and of the supplement were assessed by applying a protocol consisting of in vitro gastrointestinal digestion coupled with a Caco-2 cell model. Silicon bioaccessibility ranged from 0.89 to 8.18 mg/L and bioavailability ranged from 111 to 206 μg/L of Si for both vegetables and supplement. Furthermore, the bioavailable fractions were tested on a human osteoblast cell model following the expression of type 1 collagen and alkaline phosphatase. The results obtained highlighted that the bioavailable fraction of biofortified purslane and Swiss chard improved the expression of both osteoblast markers compared with the supplement and other vegetables. These results underline the potentially beneficial effect of biofortified leafy vegetables and also indicate the usefulness of in vitro approaches for selecting the best vegetable with positive bone effects for further in vivo research. 相似文献
85.
86.
Mozhu Ding Alexandra Wennberg Bruna Gigante Gran Walldius Niklas Hammar Karin Modig 《PLoS medicine》2022,19(8)
BackgroundThe role of cholesterol levels in the development of atrial fibrillation (AF) is still controversial. In addition, whether and to what extent apolipoproteins are associated with the risk of AF is rarely studied. In this study, we aimed to investigate the association between blood lipid levels in midlife and subsequent risk of new-onset AF.Methods and findingsThis population-based study included 65,136 individuals aged 45 to 60 years without overt cardiovascular diseases (CVDs) from the Swedish Apolipoprotein-Related Mortality Risk (AMORIS) cohort. Lipids were measured in 1985 to 1996, and individuals were followed until December 31, 2019 for incident AF (i.e., study outcome). Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using Cox regression, adjusting for age, sex, and socioeconomic status. Over a mean follow-up of 24.2 years (standard deviation 7.5, range 0.2 to 35.9), 13,871 (21.3%) incident AF cases occurred. Higher levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were statistically significantly associated with a lower risk of AF during the first 5 years of follow-up (HR = 0.61, 95% CI: 0.41 to 0.99, p = 0.013; HR = 0.64, 95% CI: 0.45 to 0.92, p = 0.016), but not thereafter (HR ranging from 0.94 [95% CI: 0.89 to 1.00, p = 0.038] to 0.96 [95% CI: 0.77 to 1.19, p > 0.05]). Lower levels of high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (ApoA-I) and higher triglycerides (TG)/HDL-C ratio were statistically significantly associated with a higher risk of AF during the entire follow-up (HR ranging from 1.13 [95% CI: 1.07 to 1.19, p < 0.001] to 1.53 [95% CI: 1.12 to 2.00, p = 0.007]). Apolipoprotein B (ApoB)/ApoA-I ratio was not associated with AF risk. The observed associations were similar among those who developed incident heart failure (HF)/coronary heart disease (CHD) and those who did not. The main limitations of this study include lack of adjustments for lifestyle factors and high blood pressure leading to potential residual confounding.ConclusionsHigh TC and LDL-C in midlife was associated with a lower risk of AF, but this association was present only within 5 years from lipid measurement and not thereafter. On the contrary, low HDL-C and ApoA-I and high TG/HDL-C ratio were associated with an increased risk of AF over almost 35 years of follow-up. ApoB/ApoA-I ratio was not associated with AF risk.Mozhu Ding and colleagues investigate investigate the association between blood lipid levels in midlife and subsequent risk of new-onset atrial fibrillation in Sweden. 相似文献
87.
M Kale R Ramsey-Goldman S Bernatsky MB Urowitz D Gladman PR Fortin M Petri E Yelin S Manzi S Edworthy O Nived S-C Bae D Isenberg A Rahman JG Hanly C Gordon S Jacobsen E Ginzler DJ Wallace GS Alarcón MA Dooley L Gottesman K Steinsson A Zoma J-L Senécal S Barr G Sturfelt L Dreyer L Criswell J Sibley JL Lee AE Clarke 《Arthritis research & therapy》2012,14(Z3):A15
88.
R Fabrini E Rosato A Gigante A Bocedi R Cianci B Barbano E Del Grosso F Ricci V Zingaretti F Salsano G Ricci 《Cell death & disease》2013,4(7):e736
Erythrocyte glutathione transferase (e-GST) is a detoxifying enzyme hyper-expressed in nephropathic patients and used recently as a biomarker for blood toxicity. Systemic sclerosis (SSc) is characterized by endothelial dysfunction and fibrosis of the skin and internal organs. Renal involvement is frequent in SSc patients. Here we show that e-GST is hyper-expressed in SSc patients (n=102) and correlates (R2=0.49, P<0.0001) with the Medsger DSS and DAI Valentini indices that quantify the severity and activity of this disease. Interestingly, e-GST does not correlate with the impairment of kidney or other specific organs taken separately. e-GST hyper-expression seems to be linked to the presence of a factor (i.e., toxin) that triggers the autoimmune disease, and not to the damage of specific organs or to oxidative stress. e-GST may be proposed as an innovative non-antibody biomarker for SSc useful to check the progress of this disease and the efficiency of new therapeutic strategies. 相似文献
89.
Isozyme electrophoresis was used to assess possible cospeciation of
parasites (cestodes of the Progamotaenia festiva complex) and their hosts
(Australian diprotodont marsupials) and to compare the extent of
interspecific genetic diversity of the parasites and their hosts. On the
basis of morphology, there are three species in the complex, although
electrophoresis revealed 14 distinct genetic types, most of which were host
specific, although there were three cases of apparent host switching. The
evolutionary relationships among the parasites were only partially
concordant with those among the hosts. Moreover, the extent of
electrophoretic diversity among the parasites was much higher than that
among hosts.
相似文献
90.
Savluchinske-Feio S Curto MJ Gigante B Roseiro JC 《Applied microbiology and biotechnology》2006,72(3):430-436
The wide potential of resin acids as bioactive agents gave rise to a growing effort in the search for new applications of the natural forms and their derivatives. In some of these compounds, the antimicrobial activity is associated to the presence in the molecules of functional groups such as the hydroxyl, aldehyde, and ketone or to their cis or trans configurations. The resin acid family covers a spectrum of antimicrobial activities against several microorganisms, from bacteria to fungi, in which the mode of action was studied by electron microscopy. The morphological alterations are consistent with an unspecific mode of action causing inhibition of the fungal growth or damaging the fungal cells in parallel with a mechanism of resistance based on the retention of the compound by the lipid accumulation. The sterol composition of phytopathogenic fungi Botrytis cinerea and Lophodermium seditiosum treated with methyl cis-7-oxo-deisopropyldehydroabietate revealed the presence of ergosterol (M+ 396) and dihydroergosterol (M+ 398) in both cultures showing that this compound did not interfere with the ergosterol metabolic pathway of both fungi. 相似文献