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A mechanism of action of DNAase, isolated by chromatin extraction with 0.4 M NaCl, on DNA is described. The enzyme is an endonuclease, it does not require the presence of double-stranded regions in the DNA molecule, does not distinct single-stranded breaks in DNA, and it preferably attacks single-stranded DNA. It hydrolyses DNA for 3'-phosphodiester bonds to octane nucleotides which are resistant to the enzyme activity. The action of the enzyme on DNA does not depend on the position of terminal phosphates. Chromatin DNAase is not specific to DNAs from different origins. 相似文献
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V G Vinter A N Askarova N L Zotkina N G Khamidullina M A Shliankevich 《Biokhimii?a (Moscow, Russia)》1988,53(11):1906-1911
It was demonstrated that neutral Mn-dependent DNAase from rat liver chromatin stimulates the incorporation of labeled precursors of DNA into high molecular weight fractions of isolated nuclear DNA. The effects of DNA-polymerase inhibitors and the properties of DNA synthesis products suggest that neutral Mn-dependent DNAase can induce replicative synthesis of DNA in the nuclei of normal and regenerating rat liver. 相似文献
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Feldspar Tunneling by Fungi along Natural Productivity Gradients 总被引:3,自引:0,他引:3
Ellis?HofflandEmail author Reiner?Giesler Antoine G.?Jongmans Nico van?Breemen 《Ecosystems》2003,6(8):739-746
Recently, it was hypothesized that ectomycorrhizas hyphae are involved in mineral tunneling. We evaluated the role of ectomycorrhizas
in mineral weathering and the ecosystem influx of basic cations by correlating mineral tunnel density to ectomycorrhizas density in two forest productivity gradients. The gradients, two gentle slopes in northern Sweden, are the result of groundwater movement and are characterized by reduced productivity upslope due to lower nitrogen availability. As expected, ectomycorrhizas density in the O horizon was higher upslope, where nitrogen availability was lower and where the vegetation was dominated by ectomycorrhizas plant species. We consistently found that tunnel formation in mineral grains was more intense in nutrient-poor sites, indicating a higher contribution of fungi to ecosystem influx of potassium and calcium. ectomycorrhizas density was positively correlated with feldspar tunnel density in the upper 2 cm of the E horizon. This suggests that ectomycorrhizas are involved in mineral tunneling. We discuss the possible involvement of ericoid mycorrhizas and saprotrophic fungi in feldspar tunneling and the role of the weathering status of mineral grains as additional factors controlling mineral funneling. 相似文献
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V G Vinter M I Beliaeva M A Shliankevich N G Khamidullina A V Polotskaia N G Zotkina 《Biokhimii?a (Moscow, Russia)》1977,42(5):823-827
Comparative effect of the DNAse from rat liver chromatin and Neurospora crassa endonuclease S1 on closed circular superhelical DNA of PM-2 phage and Simian Virus 40 is studied. It is shown that both of them--the DNAse from chromatin proteins and endonuclease S1--are specific to single-stranded regions in DNA molecular. It is suggested that chromatin protein DNAse participates in reparation processes. 相似文献
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Olivier JT Briët Gawrie NL Galappaththy Flemming Konradsen Priyanie H Amerasinghe Felix P Amerasinghe 《Malaria journal》2005,4(1):1-11
In Vietnam, a large proportion of all malaria cases and deaths occurs in the central mountainous and forested part of the country. Indeed, forest malaria, despite intensive control activities, is still a major problem which raises several questions about its dynamics. A large-scale malaria morbidity survey to measure malaria endemicity and identify important risk factors was carried out in 43 villages situated in a forested area of Ninh Thuan province, south central Vietnam. Four thousand three hundred and six randomly selected individuals, aged 10–60 years, participated in the survey. Rag Lays (86%), traditionally living in the forest and practising "slash and burn" cultivation represented the most common ethnic group. The overall parasite rate was 13.3% (range [0–42.3] while Plasmodium falciparum seroprevalence was 25.5% (range [2.1–75.6]). Mapping of these two variables showed a patchy distribution, suggesting that risk factors other than remoteness and forest proximity modulated the human-vector interactions. This was confirmed by the results of the multivariate-adjusted analysis, showing that forest work was a significant risk factor for malaria infection, further increased by staying in the forest overnight (OR= 2.86; 95%CI [1.62; 5.07]). Rag Lays had a higher risk of malaria infection, which inversely related to education level and socio-economic status. Women were less at risk than men (OR = 0.71; 95%CI [0.59; 0.86]), a possible consequence of different behaviour. This study confirms that malaria endemicity is still relatively high in this area and that the dynamics of transmission is constantly modulated by the behaviour of both humans and vectors. A well-targeted intervention reducing the "vector/forest worker" interaction, based on long-lasting insecticidal material, could be appropriate in this environment. 相似文献
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Quezada-Rivera JJ RE Soria-Guerra FS Pérez-Juárez L Martínez-González SE Valdés- Rodríguez NL Vasco-Méndez JF Morales-Domínguez 《Phyton》2019,88(1):25-35
The use of antimicrobial peptides (AMPs) synthesized
by bacteria (bacteriocins) is an alternative for combating multidrug
resistant bacterial strains and their production by recombinant route
is a viable option for their mass production. The bacteriocin E-760
isolated from the genus Enterococcus sp. has been shown to possess
inhibitory activity against Gram-negative and Gram-positive
bacteria. In this study, the expression of a chimeric protein coding
for E-760 in the nucleus of C. reinhardtii was evaluated, as well as,
its antibacterial activity. The synthetic gene E-760S was inserted
into the genome of C. reinhardtii using Agrobacterium tumefaciens.
A transgenic line was identified in TAP medium with hygromycin
and also by PCR. The increment in the culture medium temperature
of the transgenic strain at 35 °C for 10 minutes, increased the
production level of the recombinant protein from 0.14 (Noninduced
culture, NIC) to 0.36% (Induced culture, IC) of total soluble
proteins (TSP); this was quantified by an ELISA assay. Recombinant
E-760 possesses activity against Staphylococcus aureus in 0.34 U
log, Streptococcus agalactiae in 0.48 U log, Enterococcus faecium in
0.36 U log, Pseudomonas aeruginosa in 2 U log and for Klebsiella
pneumoniae, the activity was 0.07 U log. These results demonstrate
that the nucleus transformation of C. reinhardtii can function as
a stable expression platform for the production of the synthetic
gene E-760 and it can potentially be used as an antibacterial agent. 相似文献
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Rabbit antibodies against the Mn-dependent DNAse were obtained. The specificity of the anti-DNAse antibody was established by the enzyme inhibition in vitro. The enzyme activity was inhibited by more than 75 and 54% using rabbit antisera and affinity-purified IgG. Localization of the enzyme in the rat hepatocyte nuclei was studied by indirect immunofluorescence. 相似文献