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BACKGROUND AND AIMS:This paper was primarily devoted to understand the interactions of soil aggregates, organic carbon (C) and carbon cycle enzymes in aggregates under different fertilization managements, aiming to identify the effects of organic and inorganic fertilizer amendments on soil organic C accumulation and the activities of carbon cycle enzymes within aggregates in Vertisol. METHODS:A Vertisol soil following 4-year compost and inorganic fertilizer amendments, i.e. no fertilizer (CK), mineral fertilizer (FR) and 60% compost N plus 40% fertilizer N (FRM), was collected to identify the dynamics of organic C, enzymes activities and their associations with macroaggregation using aggregate fractionation techniques. RESULTS:The organic C content in all FR and FRM treatments was 8.24-41.15% higher than that in CK. An increased amounts of carbon cycle enzymes in aggregates or 0-20 cm bulk soil were also observed in FRM plots. Compared to FR, FRM significantly strengthened the structural stability of macroaggregates and the intimate connection between enzyme activities and macroaggregates. CONCLUSIONS:As a recommended measure, supplementation with organic manure such as compost strengthened the process of mutual promotion between carbon cycle enzymes and macroaggregates, and the synergistic effect would be highly beneficial to soil organic C sequestration.

Chemical composition of soil organic carbon (SOC) is central to soil fertility. We hypothesize that change in SOC content resulting from various long-term fertilization strategies accompanies the shift in SOC chemical structure. This study examined the effect of fertilization strategies along with the time of fertilizer application on the SOC composition by 13C nuclear magnetic resonance (NMR) spectroscopy. The soils (Aquic Inceptisol) subjected to seven fertilizer treatments were collected in 1989, 1999 and 2009, representing 0, 10 and 20 years of fertilization, respectively. The seven fertilizer treatments were (1-3) balanced fertilization with application of nitrogen (N), phosphorus (P) and potassium (K) including organic compost (OM), half organic compost plus half chemical fertilizer (1/2OM), and pure chemical NPK fertilizer (NPK); (4-6) unbalanced chemical fertilization without application of one of the major elements including NP fertilizer (NP), PK fertilizer (PK), and NK fertilizer (NK); and (7) an unamended control (CK). The SOC content in the balanced fertilization treatments were 2.3-52.6% and 9.4-64.6% higher than in the unbalanced fertilization/CK treatments in 1999 and 2009, respectively, indicating significant differences in SOC content with time of fertilizer application between the two treatment groups. There was a significantly greater proportion of O-alkyl C and a lower proportion of aromatic C in the balanced fertilization than in unbalanced fertilization/CK treatments in 1999, but not in 2009, because their proportions in the former treatments approached the latter in 2009. Principal component analysis further showed that the C functional groups from various fertilization strategies tended to become compositionally similar with time. The results suggest that a shift in SOC chemical composition may be firstly dominated by fertilization strategies, followed by fertilization duration.

BACKGROUND: One important protein family that functions in nucleotide excision repair (NER) factors is the SNF2 family. A newly identified mouse ERCC6-like gene, Ercc6l (excision repair cross-complementing rodent repair deficiency, complementation group 6-like), has been shown to be another developmentally related member of the SNF2 family. METHODOLOGY/PRINCIPAL FINDINGS: In this study, Sika deer Ercc6l cDNA was first cloned and then sequenced. The full-length cDNA of the Sika deer Ercc6l gene is 4197 bp and contains a 3732 bp open reading frame that encodes a putative protein of 1243 amino acids. The similarity of Sika deer Ercc6l to Bos taurus Ercc6l is 94.05% at the amino acid sequence level. The similarity, however, is reduced to 68.42-82.21% when compared to Ercc6l orthologs in other mammals and to less than 50% compared to orthologs in Gallus gallus and Xenopus. Additionally, the expression of Ercc6l mRNA was investigated in the organs of fetal and adult Sika deer (FSD and ASD, respectively) by quantitative RT-PCR. The common expression level of Ercc6l mRNA in the heart, liver, spleen, lung, kidney, and stomach from six different developmental stages of 18 Sika deer were examined, though the expression levels in each organ varied among individual Sika deer. During development, there was a slight trend toward decreased Ercc61 mRNA expression. The highest Ercc6l expression levels were seen at 3 months old in every organ and showed the highest level of detection in the spleen of FSD. The lowest Ercc6l expression levels were seen at 3 years old. CONCLUSIONS/SIGNIFICANCE: We are the first to successfully clone Sika deer Ercc6l mRNA. Ercc6l transcript is present in almost every organ. During Sika deer development, there is a slight trend toward decreased Ercc61 mRNA expression. It is possible that Ercc6l has other roles in embryonic development and in maintaining the growth of animals.