Siberian peatlands a net carbon sink and global methane source since the early Holocene

Interpolar methane gradient (IPG) data from ice cores suggest the "switching on" of a major Northern Hemisphere methane source in the early Holocene. Extensive data from Russia's West Siberian Lowland show (i) explosive, widespread peatland establishment between 11.5 and 9 thousand years ago, predating comparable development in North America and synchronous with increased atmospheric methane concentrations and IPGs, (ii) larger carbon stocks than previously thought (70.2 Petagrams, up to approximately 26% of all terrestrial carbon accumulated since the Last Glacial Maximum), and (iii) little evidence for catastrophic oxidation, suggesting the region represents a long-term carbon dioxide sink and global methane source since the early Holocene.     

影响核移植后小鼠重构胚存活因素的研究

将不同类型的供体细胞(卵丘细胞、心肌细胞和上皮细胞)的遗传物质注射到去核的MⅡ卵母细胞中,获得各种重构胚胎,以分析对小鼠卵母细胞进行核移植操作获得重构胚过程中的各种影响因素。结果表明,用Gi emas染料将挤出的卵母细胞质染色证实,可以完整地去除MⅡ卵母细胞核。对370个MⅡ卵母细胞进行去核,去核成功率为92.4%,注核成功率为82.1%;给予90 v/mm,80μsec,1次电脉冲刺激,融合率为72.1%;将融合激活后的重组胚转入KSOM培养基中,平均囊胚率达到35.8%。在胚胎重构过程中,出现了核仁显著变大,出现不同数量核仁的现象。通过比较各种重构胚胎体外后续发育,结果卵丘细胞重构胚胎的体外发育率最好。     

Acute and chronic effect of copper on levels of reduced and oxidized glutathione and nutrient uptake of tomato plants

Phytotoxicity due to copper (Cu) is generally associated with visible symptoms such as a decrease in plant shoot and root growth and chlorosis. The application of low levels of Cu or plant exposure to the metal for short periods can affect several cell processes, involving changes in the levels of metabolites related to the plant antioxidative response. The purpose of this study was to compare the response of the reduced and oxidized glutathione system and Cu uptake in tomato plants exposed to phytotoxic levels of Cu in hydroponic culture. Attention was centered on establishing whether determination of the levels of both peptides in plants exposed for a short period of time (acute treatment) compared with exposure for an extended period (chronic treatment) could be used as an early indicator of Cu stress in tomato plants. For the acute treatment, the plants were exposed to 0.4, 9, and 36 μM Cu for 48 h, and for the chronic treatment to 0.4, 3, and 12 μM Cu for 28 d. Results indicate that plants subjected to the chronic treatment showed toxicity symptoms, among them chlorosis and a drastic decrease of the aerial part and root biomass, an effect that was not observed in the plants subjected to the acute treatment. Moreover, Cu applied to the plant, either in the acute or in the chronic treatment, modified the levels of reduced and oxidized glutathione in shoots and roots. The most noticeable effect was observed on the concentration of reduced glutathione in roots, where the concentration of this peptide decreased as the Cu concentration increased, and this effect was independent of the morphological changes undergone by the root and of the time of Cu application. The similarity of the responses to the acute and the chronic treatments indicates that assessment of the redox state of glutathione in the roots of plants exposed to copper, especially the change in levels of reduced glutathione, may represent a good indicator of the early plant response to stress due to excessive Cu supply.     

Comparison of epidural and systemic tramadol for analgesia following ovariohysterectomy

The objective of the study was to compare epidural and systemic tramadol for postoperative analgesia in bitches undergoing ovariohysterectomy. Twenty animals, randomly divided into two groups, received either epidural (EPI) or intramuscular (IM) tramadol (2 mg/kg) 30 min before anesthetic induction. Analgesia, sedation, cardiorespiratory parameters, end-tidal isoflurane, blood catecholamines and cortisol, and arterial blood gases were measured at different time points up to 24 hr after agent administration. There were no differences between the two groups regarding cardiorespiratory parameters, end-tidal isoflurane, and pain scores. Two dogs in the IM and one in the EPI group required supplemental analgesia. Cortisol was increased (P<0.05) at 120 min (3.59 μg/dL and 3.27μg/dL in the IM and EPI groups, respectively) and 240 min (2.45 μg/dL and 2.54μg/dL in the IM and EPI groups, respectively) compared to baseline. Norepinephrine was also increased (P<0.05) at 120 min in both groups compared to baseline values. Epinephrine values were higher (P<0.05) in the IM group compared with the EPI group at 50 min, 120 min, and 1,440 min after tramadol administration. Epidural tramadol is a safe analgesic, but does not appear to have improved analgesic effects compared with IM administration.     

Multidrug and multispecies resistance in sheep flocks from São Paulo state, Brazil

The economic importance of sheep production is increasing worldwide simultaneously with the emergence of parasitic resistance. This study aimed to survey the current situation of management practices and parasite resistance in sheep flocks in S?o Paulo state, Brazil. A questionnaire was given to 35 sheep farmers to obtain information related to flock management practices. Of these flocks, 30 were submitted to the fecal egg count reduction test (FECRT) with at least one of the five following anthelmintics: albendazole, closantel, ivermectin, levamisole, and moxidectin, for comparison against an untreated control group. In the survey, the median number animals per flock was 301, mainly of the Santa Ines breed (in 75.8% of the flocks) and crossbred animals (in 54.5% of the flocks). The predominant farming system was semi-intensive (82.9%), using rotational grazing (80%). Selective treatment was based on FAMACHA grade (47.1%) and in clinical signs (41.2%). The most often applied anthelmintics were macrocyclic lactones (42.9-54.2% in the last three applications). Considering the anthelmintics employed in this study, 10.7% of the farms' flocks were resistant to three, 35.7% to four, and 53.6% to all five anthelmintics. The main helminth genera observed before and after treatments were Haemonchus sp. (75.8%) and Trichostrongylus sp. (19.1%), but all observed genera (Cooperia sp., Oesophagostomum sp., and Strongyloides sp.) were detected by the FECRT. Considering efficacy values less than or equal to 90% in the FECRT as resistant, 100% of flocks were resistant to albendazole and ivermectin, 96.6% to moxidectin, 92.9% to closantel, and 53.6% to levamisole. It is thus possible to conclude that multidrug resistance is widespread in sheep flocks in S?o Paulo state, Brazil, and this involves all prevalent helminth genera.     

The flow of moisture in the model sod-podzolic soil under mulch fir litter

When applying mulch to a soil surface in a decorative manner, it is possible to leave small “pockets” or unmulched zones. The capillary-sorption pressure of the soil moisture of the superficial layers in such “pockets” directly in contact with mulched areas decreases more rapidly than that of those covered with mulch as a result of more intense surface evaporation. Thus, horizontal moisture fluxes are formed that bring moisture to drier zones and provide the soil of small unmulched zones with additional moisture.     

Structure of genetic diversity among common bean (<Emphasis Type="Italic">Phaseolus vulgaris</Emphasis> L.) varieties of mesoamerican and andean origins using new developed microsatellite markers

A common bean genomic library was constructed using the ‘IAC-UNA’ variety enriched for (CT) and (GT) for microsatellite motifs. From 1,209 sequenced clones, 714 showed microsatellites distributed over 471 simple and 243 compound motifs. GA/CT and GT/CA were the most frequent motifs found among these sequences. A total of 123 microsatellites has been characterized. Out of these, 87 were polymorphic (73.7%), 33 monomorphic (26.8%), and 3 (2.4%) did not amplify at all. In a sample of 20 common bean materials selected from the Agronomic Institute Germplasm Bank, the number of alleles per locus varied 2–9, with an average of 2.82. The polymorphic information content (PIC) of each marker varied from 0.05 to 0.83, with a 0.45 average value. Cluster and principal coordinate analysis of the microsatellite data were consistent with the original assignment of the germplasm accessions into the Andean and Mesoamerican gene pools of common bean. Low polymorphism levels detected could be associated with the domestication process. These microsatellites could be a valuable resource for the bean community because of their use as new markers for genetic studies. Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users. An erratum to this article can be found at     

Temperature sensitivity of soil organic matter decomposition varies with biochar application and soil type

Biochar application has the potential to improve soil fertility and increase soil carbon stock, especially in tropical regions. Information on the temperature sensitivity of carbon dioxide(CO_2) evolution from biochar-amended soils at very high temperatures, as observed for tropical surface soils, is limited but urgently needed for the development of region-specific biochar management targeted to optimize biochar effects on soil functions. Here, we investigated the temperature sensitivity of soil respiration to the addition of different rates of Miscanthus biochar(0, 6.25, 12.5, and 25 Mg ha~(-1)) in two types of soils with contrasting textures. Biochar-amended soil treatments and their controls were incubated at constant temperatures of 20, 30, and 40℃. Overall, our results show that: i) considering data from all treatments and temperatures, the addition of biochar decreased soil CO_2 emissions when compared to untreated soils;ii) CO_2 emissions from biochar-amended soils had a higher temperature sensitivity than those from biochar-free soils; iii) the temperature sensitivity of soil respiration in sandy soils was higher than that in clay soils; and iv) for clay soils, relative increases in soil CO_2 emissions from biochar-amended soils were higher when the temperature increased from 30 to 40℃, while for sandy soils, the highest temperature responses of soil respiration were observed when increasing the temperature from 20 to 30℃. Together, these findings suggest a significantly reduced potential to increase soil organic carbon stocks when Miscanthus biochar is applied to tropical soils at high surface temperatures, which could be counteracted by the soil-and weather-specific timing of biochar application.     

Hypochlorous and peracetic acid induced oxidation of dairy proteins

Hypochlorous and peracetic acids, both known disinfectants in the food industry, were compared for their oxidative capacity toward dairy proteins. Whey proteins and caseins were oxidized under well controlled conditions at pH 8 as a function of the sanitizing concentration. Different markers for protein oxidation were monitored. The results established that the protein carbonyl content was a rather unspecific marker for protein oxidation, which did not allow one to differentiate the oxidant used especially at the lower concentrations. Cysteine, tryptophan, and methionine were proven to be the most vulnerable amino acids for degradation upon hypochlorous and peracetic acid treatment, while tyrosine was only prone to degradation in the presence of hypochlorous acid. Hypochlorous acid induced oxidation gave rise to protein aggregation, while during peracetic acid induced oxidation, no high molecular weight aggregates were observed. Protein aggregation upon hypochlorous acid oxidation could primarily be linked to tryptophan and tyrosine degradation.