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71.
Giacomo Pietramellara Judith Ascher Maria Teresa Ceccherini Paolo Nannipieri Dirk Wenderoth 《Biology and Fertility of Soils》2007,43(6):731-739
Several studies have investigated the adsorption of pure DNA on soil particles and its transformation ability. However, the presence of not purified (dirty) rather than pure DNA is more common in the extracellular soil environment. For this reason, we have investigated the adsorption
and binding of dirty DNA on montmorillonite (M) and kaolinite (K) and their transforming ability in comparison to pure DNA.
After lysis of Bacillus subtilis cells, induced by KCl, dirty DNA was characterized by the presence of cellular wall debris (cwd) and other constitutional organic components (coc). The dirty DNA was then divided into two fractions, one with cellular wall debris (DNA +cwd) and the other without cellular
wall debris (DNA −cwd). B. subtilis BD 1512 (Cmr) and BD 170 (Cms) were selected as donor and recipient bacteria, respectively, for adsorption and transformation studies. Both cwd and coc
seem to facilitate the adsorption of DNA to clay minerals, whereas only cwd promote the DNA binding on clays, protecting also
the DNA fragments below 400 bp against nucleases. Both dirty DNA fractions adsorbed and bound on clay minerals were able to
transform competent cells. 相似文献
72.
Riccardo Riffaldi Renato Levi-Minzi Alessandro Saviozzi Giacomo Vanni Alessandra Scagnozzi 《Water, air, and soil pollution》1993,69(3-4):257-264
A laboratory experiment was performed during a 40-day incubation period in order to evaluate changes in organic and inorganic compounds of soil amended with two doses of sludge obtained from olive-oil processing waste waters. Differences between the amounts of organic components of the amended soil and those of the control, although related to doses and sampling time, disappeared at the end of the experimental period. On the contrary, the inorganic anion contents were still different for the various treatments, which suggest, especially for NO3 ? and SO4 2?, a transient inhibition in the soil-sludge system. A germination test, carried out on the soil amended with different doses of sludge, indicates that after about twenty days even the soil containing the highest dose of sludge did not show toxicity any longer. 相似文献
73.
Alberto Agnelli Judith Ascher Maria Teresa Ceccherini Giacomo Pietramellara 《Soil biology & biochemistry》2004,36(5):859-868
We studied the distribution of the indigenous bacterial and fungal communities in a forest soil profile. The composition of bacterial and fungal communities was assessed by denaturing gradient gel electrophoresis (DGGE) of total and extracellular DNA extracted from all the soil horizons. Microbial biomass C and basal respiration were also measured to assess changes in both microbial biomass and activity throughout the soil profile. The 16S rDNA-DGGE revealed composite banding patterns reflecting the high bacterial diversity as expected for a forest soil, whereas 18S rDNA-DGGE analysis showed a certain stability and a lower diversity in the fungal communities. The banding patterns of the different horizons reflected changes in the microbial community structure with increasing depth. In particular, the DGGE analysis evidenced complex banding patterns for the upper A1 and A2 horizons, and a less diverse microflora in the deeper horizons. The low diversity and the presence of specific microbial communities in the B horizons, and in particular in the deeper ones, can be attributed to the selective environment represented by this portion of the soil profile. The eubacterial profiles obtained from the extracellular DNA revealed the presence of some bands not present in the total DNA patterns. This could be interpreted as the remainders of bacteria not any more present in the soil because of changes of edaphic conditions and consequent shifting in the microbial composition. These characteristic bands, present in all the horizons with the exception of the A1, should support the concept that the extracellular DNA is able to persist within the soil. Furthermore, the comparison between the total and extracellular 16S rDNA-DGGE profiles suggested a downwards movement of the extracellular DNA. 相似文献
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76.
Giacomo Tavecchia Covadonga Viedma Alejandro Martínez-Abraín 《Biological conservation》2009,142(12):3005-3012
Translocations have become one of the most commonly used tools for biodiversity restoration worldwide, however one out of three re-introduction plans fails to create a viable population or to successfully reinforce the existing one. We used results from the analysis of individual-based information on the re-introduction of a threatened waterfowl species, the crested coots Fulica cristata, to provide guidelines to maximise re-introduction success. We found that about a third of the post-release mortality took place within the first month after release. This immediate ‘cost of release’ in terms of local survival or ‘release risk factor’ seems to be a common feature of re-introduction projects, and it is likely due to the inexperience of captive-born individuals to face the new environment. This hypothesis was supported by the positive association between survival and time spent in the wild Results suggested that coots released between February and May have a slightly higher survival. A joint measure of survival and breeding probabilities indicated that birds released in late winter (February-March) had a higher chance to survive and reproduce compared to birds released later in the year. From an applied perspective our results can be used within an adaptive management framework to determine the optimum period of release, providing substantial support for future decision-making in the management of waterfowl, and other long-term projects of re-introduction of threatened vertebrate species. 相似文献
77.
Rui?LiuEmail author Helen?L.?Hayden Helen?Suter Hangwei?Hu Shu?Kee?Lam Jizheng?He Pauline?M.?Mele Deli?Chen 《Biology and Fertility of Soils》2017,53(1):141-152
In recent years, identification of the microbial sources responsible for soil N2O production has substantially advanced with the development of isotope enrichment techniques, selective inhibitors, mathematical models and the discoveries of specific N-cycling functional genes. However, little information is available to effectively quantify the N2O produced from different microbial pathways (e.g. nitrification and denitrification). Here, a 15N-tracing incubation experiment was conducted under controlled laboratory conditions (50, 70 and 85% water-filled pore space (WFPS) at 25 and 35 °C). Nitrification was the main contributor to N2O production. At 50, 70 and 85% WFPS, nitrification contributed 87, 80 and 53% of total N2O production, respectively, at 25 °C, and 86, 74 and 33% at 35 °C. The proportion of nitrified N as N2O (P N2O) increased with temperature and moisture, except for 85% WFPS, when P N2O was lower at 35 °C than at 25 °C. Ammonia-oxidizing archaea (AOA) were the dominant ammonia oxidizers, but both AOA and ammonia-oxidizing bacteria (AOB) were related to N2O emitted from nitrification. AOA and AOB abundance was significantly influenced by soil moisture, more so than temperature, and decreased with increasing moisture content. These findings can be used to develop better models for simulating N2O from nitrification to inform soil management practises for improving N use efficiency. 相似文献
78.
Ecological and histopathological aspects of Didymodiclinus sp. (Trematoda: Didymozoidae) parasite of the dusky grouper,Epinephelus marginatus (Osteichthyes: Serranidae), from the western Mediterranean Sea 下载免费PDF全文
Marta Polinas Salvatore Mele Francesc Padrós Paolo Merella Elisabetta Antuofermo Adam Gouraguine Olga Reñones 《Journal of fish diseases》2018,41(9):1385-1393
The dusky grouper Epinephelus marginatus (Lowe) is an ecologically and commercially important fish species of the Atlantic and Mediterranean coastal rocky habitats. Despite records of didymozoid infections in several grouper species, the identification and pathogenesis of these parasites in E. marginatus are lacking. The aim of this study is to characterize the didymozoids of E. marginatus, particularly their mechanisms of infection and histopathological features. Dusky groupers (n = 205) were caught off Majorca Island (western Mediterranean Sea) and examined for parasites. Of the fish sampled, 45% were infected with white and yellow didymozoid capsules and brown nodules, found on the gills and pseudobranchs. Parasite abundance had a strong positive relationship with the fish length; only fish larger than 20 cm were infected, suggesting infection via consumption of an intermediate host, for which E. marginatus size was a limiting factor. The capsules contained two convoluted viable adult trematodes, identified as Didymodiclinus sp., in close contact with host capillary vessels, with no evidence of the tissue inflammatory response. Conversely, nodules containing degraded parasites were surrounded by an intense inflammatory infiltrate. The findings suggest that Didymodiclinus sp. have the potential to evade the host's immune system by inhibiting the inflammatory response. 相似文献
79.
COMPUTED TOMOGRAPHIC FEATURES OF INCISOR PSEUDO‐ODONTOMAS IN PRAIRIE DOGS (CYNOMYS LUDOVICIANUS) 下载免费PDF全文
Igor Pelizzone Francesco Di Ianni Antonella Volta Giacomo Gnudi Sabrina Manfredi Mara Bertocchi Enrico Parmigiani 《Veterinary radiology & ultrasound》2017,58(3):273-283
Maxillary incisor pseudo‐odontomas are common in pet prairie dogs and can cause progressive respiratory obstruction, while mandibular pseudo‐odontomas are rarely clinically significant. The aim of this retrospective cross‐sectional study was to describe CT features of maxillary and mandibular incisor pseudo‐odontomas vs. normal incisors in a group of pet prairie dogs. All pet prairie dogs with head CT scans acquired during the period of 2013–2015 were included. A veterinary radiologist who was aware of final diagnosis reviewed CT scans and recorded qualitative features of affected and normal incisors. Mean density values for the pulp cavity and palatal and buccal dentin were also recorded. A total of 16 prairie dogs were sampled (12 normal maxillary incisors, 20 confirmed maxillary incisor pseudo‐odontomas, 20 normal mandibular incisors, 12 presumed mandibular incisor pseudo‐odontomas). Maxillary incisors with confirmed pseudo‐odontomas had a significantly hyperattenuating pulp and dentin in the reserve crown and apical zone, when compared to normal maxillary incisors. Pseudo‐odontomas appeared as enlargements of the apical zone with a globular/multilobular hyperattenuating mass formation haphazardly arranged, encroaching on midline and growing caudally and ventrally. Presumed mandibular incisor pseudo‐odontomas had similar CT characteristics. In 60% of prairie dogs with maxillary incisor pseudo‐odontomas, the hard palate was deformed and the mass bulged into the oral cavity causing loss of the palatine bone. The common nasal meatus was partially or totally obliterated in 81.8% of prairie dogs with maxillary pseudo‐odontomas. Findings supported the use of CT for characterizing extent of involvement and surgical planning in prairie dogs with pseudo‐odontomas. 相似文献
80.