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151.
Anissa Haddar Ali Bougatef Rym Agrebi Alya Sellami-Kamoun Moncef Nasri 《Process Biochemistry》2009,44(1):29-35
An extracellular bleach stable protease producing strain was isolated from marine water sample and identified as Bacillus mojavensis A21 on the basis of the 16S rRNA gene sequencing and biochemical properties. The A21 alkaline protease was purified from the culture supernatant to homogeneity using acetone precipitation, Sephadex G-75 gel filtration and CM-Sepharose ion exchange chromatography, with a 6.43-fold increase in specific activity and 16.56% recovery. The molecular weight of the purified enzyme was estimated to be 20 kDa by SDS-PAGE and gel filtration. The enzyme was highly active over a wide range of pH from 7.0 to 13.0, with an optimum at pH 8.5. The relative activities at pH 11.0 and 12.0 were about 80 and 71.7% of that obtained at pH 8.5. The enzyme was extremely stable in the pH range of 7.0–12.0. It exhibited maximal activity at 60 °C. The thermostability of the enzyme was significantly increased by the addition of CaCl2. The activity of the enzyme was totally lost in the presence of PMSF, suggesting that the purified enzyme is a serine protease.The N-terminal amino acid sequence of the first 20 amino acids of the purified protease was DINGGGATLPQKLYQTSGVL. B. mojavensis A21 protease showed low homology with bacterial peptidases, suggesting that the enzyme is a new protease.The alkaline protease showed high stability towards anionic (0.1% SDS) and non-ionic (1 and 5% Tween 80 and 1% Triton X-100) surfactants. In addition, the enzyme was relatively stable towards oxidizing agents, retaining more than 79 and 70% of its initial activity after 1 h incubation in the presence of 1% H2O2 and 0.1% sodium perborate, respectively. The enzyme showed excellent stability with a wide range of commercial solid and liquid detergents at 30 and 40 °C. Considering its promising properties, B. mojavensis A21 may find potential application in laundry detergents. 相似文献
152.
Rym Agrebi Anissa Haddar Noomen Hmidet Kemel Jellouli Laila Manni Moncef Nasri 《Process Biochemistry》2009,44(11):1252-1259
A novel fibrinolytic enzyme, subtilisin BSF1, from a newly isolated Bacillus subtilis A26 was purified, characterized and the gene was isolated and sequenced. The subtilisin BSF1 was purified to homogeneity by five-step procedure with a 4.97-fold increase in specific activity and 6.28% recovery. The molecular weight of the purified enzyme was estimated to be 28 kDa by SDS-PAGE and gel filtration. The purified enzyme exhibited high fibrinolytic activity on fibrin agar plates.Interestingly, the enzyme was highly active over a wide range of pH from 7.0 to 12.0, with an optimum at pH 9.0. The relative activities at pH 10.0 and 11.0 were 97.8% and 85.2% of that at pH 9.0. The optimum temperature for enzyme activity was 60 °C. The activity of subtilisin BSF1 was totally lost in the presence of PMSF, suggesting that the purified enzyme is a serine protease. The N-terminal amino acid sequence of the first 11 amino acids (aa) of the purified fibrinolytic enzyme was AQSVPYGISQI.The bsf1 gene encoding the subtilisin BSF1 was isolated and its DNA sequence was determined. The bsf1 gene consisted of 1146 bp encoding a pre-pro-protein of 381 amino acids organized into a signal peptide (29 aa), a pro-peptide (77 aa) and a mature domain (275 aa). The deduced amino acids sequence of the mature enzyme (BSF1) differs from those of nattokinase from B. subtilis natto and subtilisin DFE from Bacillus amyloliquefaciens DC-4 by 5 and 39 amino acids, respectively. 相似文献
153.
Moncef Boulila 《Plant Molecular Biology Reporter》2009,27(2):189-198
Genetic RNA recombination plays an important role in viral evolution. The evolutionary history of Prunus necrotic ringspot virus (PNRSV) has been extensively studied, but knowledge of recombination in its genome is still lacking.
To investigate the recombination events in this virus, 67 accessions composed by 62 isolates retrieved from the databanks
and five Tunisian isolates described in this study were analyzed. The use of RECCO algorithm which is based on cost minimization
allowed us to detect several breakpoints in the coat protein gene (CP) of three out of five isolates from Tunisia and one
from Poland. Moreover, a recombination signal was also detected in the putative cell-to-cell movement protein-encoding gene
of an isolate from the USA. Tajima Neutrality test implemented in MEGA4 program indicated the occurrence of a high level of
deletion/insertion events in the sequences. The evolutionary historical relationships were determined by constructing a dendrogram
using neighbor joining, minimum evolution, maximum parsimony, maximum likelihood, and unweighted pair group method with arithmetic
mean (UPGMA). The first four analyses gave similar results. Three classical groups (PE 5, PV 32, and PV 96) were delineated.
The recombinant isolates from Tunisia clustered in a distinct clade except for one nonrecombinant (Ghernghezel) which revealed
to be a member of PV 32 group. In contrast, UPGMA algorithm divided the Tunisian isolates in three distinct subgroups. Apart
from recombination, reassortment is still an open question among many others and may also represent another way to explore
the genetic diversity of PNRSV. 相似文献
154.
155.
Outi Hovatta Marisa Jaconi Virpi T?h?nen Frédérique Béna Stefania Gimelli Alexis Bosman Frida Holm Stefan Wyder Evgeny M. Zdobnov Olivier Irion Peter W. Andrews Stylianos E. Antonarakis Marco Zucchelli Juha Kere Anis Feki 《PloS one》2010,5(4)
The first Swiss human embryonic stem cell (hESC) line, CH-ES1, has shown features of a malignant cell line. It originated from the only single blastomere that survived cryopreservation of an embryo, and it more closely resembles teratocarcinoma lines than other hESC lines with respect to its abnormal karyotype and its formation of invasive tumors when injected into SCID mice. The aim of this study was to characterize the molecular basis of the oncogenicity of CH-ES1 cells, we looked for abnormal chromosomal copy number (by array Comparative Genomic Hybridization, aCGH) and single nucleotide polymorphisms (SNPs). To see how unique these changes were, we compared these results to data collected from the 2102Ep teratocarcinoma line and four hESC lines (H1, HS293, HS401 and SIVF-02) which displayed normal G-banding result. We identified genomic gains and losses in CH-ES1, including gains in areas containing several oncogenes. These features are similar to those observed in teratocarcinomas, and this explains the high malignancy. The CH-ES1 line was trisomic for chromosomes 1, 9, 12, 17, 19, 20 and X. Also the karyotypically (based on G-banding) normal hESC lines were also found to have several genomic changes that involved genes with known roles in cancer. The largest changes were found in the H1 line at passage number 56, when large 5 Mb duplications in chromosomes 1q32.2 and 22q12.2 were detected, but the losses and gains were seen already at passage 22. These changes found in the other lines highlight the importance of assessing the acquisition of genetic changes by hESCs before their use in regenerative medicine applications. They also point to the possibility that the acquisition of genetic changes by ESCs in culture may be used to explore certain aspects of the mechanisms regulating oncogenesis. 相似文献
156.
Mrabet M Mnasri B Romdhane SB Laguerre G Aouani ME Mhamdi R 《FEMS microbiology ecology》2006,56(2):304-309
In a previous work, we showed that non-nodulating agrobacteria strains were able to colonize root nodules of common bean. Both rhizobia and agrobacteria co-existed in the infected nodules. No impact on symbiosis was found in laboratory conditions when using sterile gravel as a support for growth. In this study, soil samples originating from different geographic and agronomic regions in Tunisia were inoculated with a mixture of agrobacteria strains isolated previously from root nodules of common bean. A significant effect on nodulation and vegetal growth of common bean was observed. Characterization of nodulating rhizobia and comparison with non-inoculated controls showed a biased genetic structure. It seemed that Rhizobium gallicum was highly inhibited, whereas nodulation by Sinorhizobium medicae was favored. Co-inoculation of non-sterile soils with R. gallicum and agrobacteria confirmed these findings. In vitro antibiosis assays indicated that agrobacteria exercised a significant antagonism against R. gallicum. 相似文献
157.
158.
Ontogeny of serum and anterior pituitary gland PRL contents was investigated. Pituitary PRL concentrations were found to be low in fetus by 19th day of gestation and to rise slowly after birth with no sex differences being apparent until day 30. Adult levels were reached in males on day 15, while in females they were reached beyond this stage. Serum PRL levels exhibited a similar developmental pattern. In adult rats ether stress stimulated basal serum PRL significantly, with maximum effect one minute after onset of stress. The same pattern was seen with immature animals of 15-20 and 30 days of age. In contrast, in 2 or 6 day-old neonates, serum PRL concentrations remained unaffected by stress. This lack of responsiveness suggests the existence of a transient impairment of lactotrophs to respond to stressful stimuli during postnatal life. Adrenalectomy increased PRL release in adult and newborn rats from day 15 onward and potentiated the response of lactotrophs. Moreover, after adrenalectomy, 6 day-old rats became sensitive to ether stress, while acute treatment with dexamethasone abolished completely this response. In adult or 15 day-old neonates administration of TRH or sulpiride resulted in a marked increase in serum PRL levels. However, at 6 days TRH did not affect resting serum PRL concentrations significantly, whereas sulpiride remained efficient. Moreover, at this age, dopamine inhibited stress-induced PRL release and reduced the stimulatory effect of sulpiride.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
159.
Moncef Nasri Abdelhafidh Dhouib Fathi Zorguani Habib Kriaa Radouan Ellouz 《Biotechnology letters》1989,11(12):865-870
Summary Lysine production by immobilizedCorynebacterium sp cells in alginate gel beads was investigated in flasks. ImmobilizedCorynebacterium sp cells exhibited a slightly greater lysine production than free cells and accumulated 60 g/l of L-lysine at maximum, when cultured for 120h in a medium containing 200g/l glucose as carbon source. Several factors, such as inoculum size, incubation time and alginate gel concentration were examined in order to improve lysine production by immobilized growing cells. 相似文献
160.
Smaoui M Koubaa N Hammami S Abid N Feki M Chaaba R Attia N Abid M Hammami M 《Prostaglandins, leukotrienes, and essential fatty acids》2006,74(5):323-329
BACKGROUND: The antioxidant enzymes: superoxide dismutase (Cu/Zn SOD) and glutathione peroxidase (GSH-Px) provide a defense against the damage of cells by reactive oxygen species, which increased in diabetic state. It was demonstrated that dietary treatment could improve the antioxidant status in patients with type 2 diabetes mellitus. This study was undertaken to determine if erythrocyte Cu/Zn SOD and GSH-Px activities correlate with dietary nutrients in 35 selected type 2 diabetic patients (21 women and 14 men) without diabetic complications. RESULTS: We found that erythrocyte Cu/Zn SOD was diminished in patients with poor controlled diabetes and GSH-Px activity was significantly decreased in obese compared with non-obese type 2 diabetic patients (1.07+/-0.87 and 2.36+/-1.99 U/ml, respectively; P=0.024). Both erythrocyte Cu/Zn SOD and GSH-Px activities were positively correlated to erythrocyte omega3-polyunsaturated fatty acids (PUFA). In non-obese diabetic patients, only GSH-Px activity was correlated negatively to the fraction of linoleic acid (18:2omega6) and arachidonic acid (20:4omega6) in erythrocytes phospholipids. CONCLUSIONS: The data of this study reveal that activities of erythrocyte antioxidant enzymes were altered in type 2 diabetic patients. Further studies are needed to determine if diet supplemented with omega3-PUFA is required to improve antioxidant defense system in diabetic state. 相似文献