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111.
Ruiz C Falcocchio S Pastor FI Saso L Diaz P 《Applied and environmental microbiology》2007,73(8):2423-2431
Bacterial lipases are attracting an enormous amount of attention due to their wide biotechnological applications and due to their roles as virulence factors in some bacteria. Helicobacter pylori is a significant and widespread pathogen which produces a lipase(s) and phospholipases that seem to play a role in mucus degradation and the release of proinflammatory and cytotoxic compounds. However, no H. pylori lipase(s) has been isolated and described previously. Therefore, a search for putative lipase-encoding genes was performed by comparing the amino acid sequences of 53 known lipolytic enzymes with the deduced proteome of H. pylori. As a result, we isolated, cloned, purified, and characterized EstV, a novel lipolytic enzyme encoded by open reading frame HP0739 of H. pylori 26695, and classified it in family V of the bacterial lipases. This enzyme has the properties of a small, cell-bound carboxylesterase (EC 3.1.1.1) that is active mostly with short-chain substrates and does not exhibit interfacial activation. EstV is stable and does not require additional cofactors, and the maximum activity occurs at 50 degrees C and pH 10. This unique enzyme is the first lipase isolated from H. pylori that has been described, and it might contribute to ulcer development, as inhibition by two antiulcer substances (beta-aescin and glycyrrhizic acid) suggests. EstV is also the first lipase from an epsilon-proteobacterium to be described. Furthermore, this enzyme is a new member of family V, probably the least-known family of bacterial lipases, and the first lipase of this family for which kinetic behavior, inhibition by natural substances, and other key biochemical features are reported. 相似文献
112.
Nasi M Pinti M Bugarini R Troiano L Lugli E Bellodi C Mussini C Borghi V Trenti T Balli F Esposito R Cossarizza A 《Immunogenetics》2005,57(9):628-635
Fas and Fas ligand (FasL) are the main genes that control cell death in the immune system. Indeed, they are crucial for the regulation of T lymphocyte homeostasis because they can influence cell proliferation. A strong debate exists on the importance of Fas/FasL system during HIV infection, which is characterized by the loss of CD4+ T cells directly, or indirectly, caused by the virus. To investigate whether the genetic background of the host plays a role in the immunoreconstitution, we studied the influence of different Fas and FasL polymorphisms on CD4+ T lymphocyte count and plasma viral load following initiation of highly active antiretroviral therapy (HAART) in drug-naïve HIV+ patients. We studied 131 individuals, who were compared to 136 healthy donors. Statistical analysis was performed by using X 2 test, Fischer's Exact Test, and analysis for repeated measurements. The group of HIV+ patients had an unexpected lower frequency of FasLnt169 polymorphism (delT allele) than healthy controls (p=0.039). We then observed no significant differences in the immune reconstitution, in terms of CD4+ T cell increase, when the influence of single alleles of the gene Fas or FasL was considered. However, the combination of some polymorphisms of Fas or FasL significantly influenced CD4+ T cell production and viral load decrease, showing that these genes can play a role in the immunoreconstitution triggered by antiretroviral therapy. 相似文献
113.
114.
Sequence variation in nuclear ribosomal small subunit,internal transcribed spacer and large subunit regions of Rhizophagus irregularis and Gigaspora margarita is high and isolate‐dependent 下载免费PDF全文
Odile Thiéry Martti Vasar Teele Jairus John Davison Christophe Roux Paula‐Ann Kivistik Andres Metspalu Lili Milani Ülle Saks Mari Moora Martin Zobel Maarja Öpik 《Molecular ecology》2016,25(12):2816-2832
Arbuscular mycorrhizal (AM) fungi are known to exhibit high intra‐organism genetic variation. However, information about intra‐ vs. interspecific variation among the genes commonly used in diversity surveys is limited. Here, the nuclear small subunit (SSU) rRNA gene, internal transcribed spacer (ITS) region and large subunit (LSU) rRNA gene portions were sequenced from 3 to 5 individual spores from each of two isolates of Rhizophagus irregularis and Gigaspora margarita. A total of 1482 Sanger sequences (0.5 Mb) from 239 clones were obtained, spanning ~4370 bp of the ribosomal operon when concatenated. Intrasporal and intra‐isolate sequence variation was high for all three regions even though variant numbers were not exhausted by sequencing 12–40 clones per isolate. Intra‐isolate nucleotide variation levels followed the expected order of ITS > LSU > SSU, but the values were strongly dependent on isolate identity. Single nucleotide polymorphism (SNP) densities over 4 SNP/kb in the ribosomal operon were detected in all four isolates. Automated operational taxonomic unit picking within the sequence set of known identity overestimated species richness with almost all cut‐off levels, markers and isolates. Average intraspecific sequence similarity values were 99%, 96% and 94% for amplicons in SSU, LSU and ITS, respectively. The suitability of the central part of the SSU as a marker for AM fungal community surveys was further supported by its level of nucleotide variation, which is similar to that of the ITS region; its alignability across the entire phylum; its appropriate length for next‐generation sequencing; and its ease of amplification in single‐step PCR. 相似文献
115.
116.
Cuellar MA Salas C Cortés MJ Morello A Diego Maya J Preite MD 《Bioorganic & medicinal chemistry》2003,11(12):2489-2497
The Diels-Alder reaction between two polygodial-derived dienes and simple quinones to yield substituted naphtho- and anthraquinones, is described. The in vitro trypanocide activity for the series was determined. Two of the new compounds showed an activity ten and two times higher, respectively, than nifurtimox and benznidazole, the medicines of choice for the treatment of the acute Chagas' disease. 相似文献
117.
Localization of Usher syndrome type II to chromosome 1q 总被引:17,自引:0,他引:17
W J Kimberling M D Weston C M?ller S L Davenport Y Y Shugart I A Priluck A Martini M Milani R J Smith 《Genomics》1990,7(2):245-249
Usher syndrome is characterized by congenital hearing loss, progressive visual impairment due to retinitis pigmentosa, and variable vestibular problems. The two subtypes of Usher syndrome, types I and II, can be distinguished by the degree of hearing loss and by the presence or absence of vestibular dysfunction. Type I is characterized by a profound hearing loss and totally absent vestibular responses, while type II has a milder hearing loss and normal vestibular function. Fifty-five members of eight type II Usher syndrome families were typed for three DNA markers in the distal region of chromosome 1q: D1S65 (pEKH7.4), REN (pHRnES1.9), and D1S81 (pTHH33). Statistically significant linkage was observed for Usher syndrome type II with a maximum multipoint lod score of 6.37 at the position of the marker THH33, thus localizing the Usher type II (USH2) gene to 1q. Nine families with type I Usher syndrome failed to show linkage to the same three markers. The statistical test for heterogeneity of linkage between Usher syndrome types I and II was highly significant, thus demonstrating that they are due to mutations at different genetic loci. 相似文献
118.
Luca M. Neri Daniela Milani Marco Marchisio Lucia Bertolaso Fiorenzo Marinelli Francesco A. Manzoli Silvano Capitani 《Histochemistry and cell biology》1993,100(2):121-129
The rat pheochromocytoma PC12 cell line, which differentiates into sympathetic neurons under nerve growth factor (NGF) treatment, contains at least three phosphoinositidase C (PIC) isozymes, PIC , PIC , PIC . These isozymes have been previously shown to display a different subcellular localization. To determine whether or not NGF induces changes in the presence and/or distribution of PIC isozymes during PC12 neural differentiation, studies were carried out by means of in situ immunocytochemistry. After NGF administration the proliferative activity was progressively reduced to very low levels, as measured by bromodeoxyUridine incorporation, and a neuron-like morphology was displayed by almost all cells. In unstimulated PC12 cells, PIC was detected in the nucleus whereas PIC was only cytoplasmic; PIC was found in both cell compartments. In cells treated with NGF for 3 days, neural processes extended to twice the diameter of the cell body; the isoform was concentrated near the nucleus, while the immunoreactivity of the form remained constant and the form was increased. After 10 days of treatment with NGF, PIC was hardly detectable and PIC immunostaining was considerably decreased. On the contrary, PIC progressively increased and, after 14 days of NGF exposure, fully differentiated cells displayed an intense labelling of cell body and neurites. In the same cells, PIC and PIC were almost negative. These results suggest that NGF dependent neural differentiation is related to the selective down regulation of PIC and and the increase of PIC isozyme associated with the decrease of cell proliferation. 相似文献
119.
Claudio Farías-Valenzuela Cristian Pérez-Luco Rodrigo Ramírez-Campillo Cristian Álvarez Mauricio Castro-Sepúlveda 《Revista espa?ola de geriatría y gerontología》2018,53(3):141-144
Background
Handgrip strength (HS) and peak oxygen consumption (Vo2peak) are powerful predictors of cardiovascular risk, although it is unknown which of the two variables is the better predictor.Aim
The objective of the following study was to relate HS and Vo2peak to cardiovascular risk markers in older Chilean women.Methods
Physically active adult women (n = 51; age, 69 ± 4.7 years) participated in this study. The HS and Vo2peak were evaluated and related to the anthropometric variables of body mass, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist ratio (WR), and waist height ratio (WHR), as well as with the cardiovascular variables systolic (SBP) and diastolic (DBP) and cardiac recovery in one minute (RHR1). A multilinear regression model was used for the analysis of the associated variables (P < .05).Results
The cardiovascular risk markers associated (P < .05) with the handgrip strength of the dominant limb (HSDL) were body mass, BMI, WR, and WHR. The handgrip strength of the non-dominant limb (HSNDL) was associated with body mass. Vo2peak was associated with body mass, BMI, HC and RHR1. The multilinear regression model showed a value of r = 0.43 in HSDL, r = 0.39 in HSNDL and r = 0.69 in peak Vo2.Conclusion
Although HS and Vo2peak were related to cardiovascular risk markers, Vo2peak offers greater associative power with these cardiovascular risk factors. 相似文献120.
Ecological indicators for assessing ecological success of forest restoration: a world review 下载免费PDF全文
Restoration is increasingly being used to reverse degradation and destruction of forest ecosystems. With increasing investment in restoration, there is an urgent need to develop effective programs to assess treatment efficacy and effects. We conducted a global review of forest restoration assessments, in order to identify geographic trends in the locations where assessments have been implemented and the specific ecological attributes (ecosystem composition, structure, and function) and indicators being used to measure effects. We found that the number of forest restoration assessments varied by region and was not related to degree of degradation or restoration need. Some regions, like Africa, which have experienced high rates of forest loss and degradation, had few assessments. The majority (43%) of assessments included indicators for only two of three key ecological attributes (composition‐structure or composition‐function) and assessments on average used fewer than three indicators per attribute. The most commonly employed indicators for composition were richness and abundance of plant species and for structure were height and diameter of trees, variables that are generally relatively easy to measure. The use of functional indicators has been increasing over time and they are now more commonly used than structural indicators. The most common functional indicators were soil functions. Most investigators evaluated treatment effects for 6–10 years after implementation. Our findings related to gaps in analysis of ecological indicators can serve as a guide for developing monitoring and assessment protocols for current global forest restoration initiatives by 2020–2030. 相似文献