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851.
Srdjan Bojović Zorica Šarac Biljana Nikolić Vele Tešević Marina Todosijević Milan Veljić Petar D. Marin 《化学与生物多样性》2012,9(12):2761-2774
This is the first report on the composition and variability of the needle‐wax n‐alkanes in natural populations of Pinus nigra in Serbia. Samples of 195 trees from seven populations belonging to several infraspecific taxa (ssp. nigra, var. gocensis, ssp. pallasiana, and var. banatica) were analyzed. In general, the size of the n‐alkanes ranged from C16 to C33, with the exception of ssp. nigra, for which it ranged from C18 to C33. The most abundant were C23‐, C25‐, C27‐, and C29‐alkanes. The needle waxes of Populations I–III and V were characterized by a higher content of C23‐, C25‐, and C27‐alkanes and a lower content of C24‐, C26‐, C28‐, and C30‐alkanes, compared to the other populations, and the trees of these populations could be assigned to ssp. nigra. The samples of Population VI were characterized by higher amounts of C22‐, C24‐, C30‐, and C32‐alkanes and lower amounts of C25‐ and C27‐alkanes, and the trees could be considered as ssp. pallasiana. The samples of Population VII, consisting of trees belonging to var. banatica, were richer in C29‐, C31‐, and C33‐alkanes. The wax compositions of Populations IV and V, both composed of trees previously determined as P. nigra var. gocensis, showed a tendency of splitting. Indeed, the alkane composition of Population IV was closer to that of ssp. pallasiana pines, while that of Population V was more similar to that of ssp. nigra pines. From the results presented here, it is obvious that in the central part of the Balkan Peninsula, significant diversification and differentiation of the populations of black pine exists, and these populations could be defined as different intraspecific taxa. Our results also indicate the validity of n‐alkanes as chemotaxonomic characters within this aggregate. 相似文献
852.
The activities and isoenzyme pattern of catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD) have been studied
during germination of Chenopodium murale seeds. CAT and SOD activities were similar in dry seeds and during first 2 d of imbibition. CAT activity increased during
radicle protrusion and early seedling development. The maximum SOD activity was found at final stages of germination and early
seedling development. POD activity was not detected until the 6th day of germination, indicating POD involvement not until early seedling development. Gibberellic acid (GA3, 160 μM) delayed and synchronized C. murale germination. 相似文献
853.
The history of green fluorescent protein (GFP) as a marker is less than 10 years old, but it has already made a major impact on many areas of natural sciences, especially on cell biology and histochemistry. GFP can be detected in living cells without selection or staining and it can be fused to other proteins to yield fluorescent chimeras. The potential of GFP has also been recognised by gene therapy researchers and various GFP-tagged therapeutic proteins have been constructed. These chimeric proteins have been used to determine the expression level, site and time course of the therapeutic gene, or the correlation between gene transfer rate and therapeutic outcome. This review summarises the status of the applications of GFP fusions in gene therapy research. 相似文献
854.
855.
S. Stepanović I. Ćirković S. Djukić D. Vuković M. Švabić‐Vlahović 《Letters in applied microbiology》2008,47(4):339-341
Aims: The aim of this study was to explore the occurrence of methicillin‐resistant staphylococci in a large urban public transport system. Methods and Results: Samples were taken from hand rails, which passengers hold onto when they are standing. In total, 1400 swabs taken from 55 vehicles (trolleybuses, trams and buses) were examined. As many as 30·1% samples were positive for the presence of methicillin‐resistant coagulase‐negative staphylococci (MRCoNS), but none for methicillin‐resistant Staphylococcus aureus (MRSA). MRCoNS were isolated from all 55 vehicles. Nearly 50% of MRCoNS isolates displayed resistance not only to beta‐lactams, but at least to two or more other classes of antimicrobials as well. Conclusions: This study demonstrated widespread occurrence of MRCoNS on hand rails in public transport vehicles. MRSA was not detected. Significance and Impact of the Study: The recovery of methicillin‐resistant staphylococci from public transport system implies a potential risk for transmission of these bacteria in an out‐hospital environment. 相似文献
856.
857.
Jacek Wierzchowski Alicja Stachelska-Wierzchowska Beata Wielgus-Kutrowska Goran Mikleušević 《Analytical biochemistry》2014
Two nontypical nucleosides, 7-β-d-ribosyl-2,6-diamino-8-azapurine and 8-β-d-ribosyl-2,6-diamino-8-azapurine, have been found to exhibit moderately good, and selective, substrate properties toward calf and bacterial (Escherichia coli) forms of purine nucleoside phosphorylase (PNP). The former compound is effectively phosphorolysed by calf PNP and the latter by PNP from E. coli. Both compounds are fluorescent with λmax ∼ 425 to 430 nm, but the reaction product, 2,6-diamino-8-azapurine, emits in a different spectral region (λmax ∼ 363 nm) with nearly 40% yield, providing a strong fluorogenic effect at 350 to 360 nm. 相似文献
858.
CDC traps were used to determine the maximum radius of carbon dioxide attraction within forest habitat (a forest plant community with Carpino betuli-Quercetum roburis). A central CDC trap with dry ice (CO2) was set as the source of attractant (Ck). Around Ck trap two circles (A and B) of CDC traps without attractants were placed. Circle A was constituted of 6 CDC traps and Circles B with 12 CDC traps. Radius from Circle A and B to the Ck trap were used to determine CO2 maximum range. During the experiment, the average emissions of CO2 were 0.08 to 0.1 g s?1. Regarding the data, optimal radius attraction where CO2 was affected on mosquitoes was between 55 and 70 m from the source. Results propose that the distance between traps should be greater than 140 m, to ensure the absence of bias by each of the traps. Changes in CO2 maximum concentration and wind velocity directly affected the catch of different species. The number of Ochlerotatus sticticus collected was positively correlated with wind speed. 相似文献
859.
The presence and activity of deoxyribonucleases in the cortex and endosome sections from a sponge, the sea orange Tethya aurantium, were investigated. The maximal enzyme activity in sponge homogenate was detected at pH 4.27, pH 7.0 and pH 8.5–8.75. Among
different specimens, several distinct patterns of neutral DNase isozymes were observed in the cortex section. In each investigated
specimen the highest neutral DNase activity belonged to high molecular weight proteins (up to75 kDa). The acid DNases showed
a low level of enzyme activity. In the endosome section the acid DNase activity was up to ten times higher than in the cortex
and the presence of DNase II-like protein was detected. Neutral DNase, which expressed the highest enzyme activity in all
the investigated specimens, has a molecular weight of 20 kDa and belongs to the DNase I-like family. The results indicate
that the activity of neutral and acid DNases is related to sponge sections and their biological functions. The cortex, as
the sponge section that communicates with the environment, expresses high interindividual variability and heterogeneity of
neutral DNases, while the endosome section, where the intracellular digestion is localized, is a site of high acid DNase activity. 相似文献
860.
We have previously found apparent differences in Gpdh allele frequences between borrelia infected and uninfected Ixodes ricinus as revealed by native gel electrophoresis of allozyme polymorphisms. The present study deals with the genetic basis of the observed allozyme polymorphism. Multiple sequence alignment of 36 Gpdh open reading frames identified a total of 40 polymorphic nucleotide sites. Of the 40 polymorphic nucleotide sites, 34 were silent (did not result in amino acid residue change), while six were active causing a change in the amino acid chain. All polymorphic amino acid sites were situated within the N-terminal NAD-binding domain, whereas the C-terminal substrate-binding domain was highly conserved. Analysis of the obtained Gpdh sequences and GPDH allozyme polymorphisms for individual ticks pointed to amino acid changes at positions 61 (glycine-to-glutamic acid), 64 (serine-to-cysteine) and 102 (glycine-to-arginine) as a key for differential mobility of GPDH allozymes in an electric field. Our findings are discussed in the context of the molecular basis of I. ricinus host finding behavior. 相似文献