RESUMO
Frequent outbreaks have made Chlorops oryzae one of the major pests of rice in some regions. In order to understand the ecological adaptation of C. oryzae at the molecular level, and provide a scientific basis for formulating management strategies, we used two molecular markers, COI and ITS1 sequences, to systematically analyze the genetic structure of 31 populations. The higher haplotype diversity and lower nucleotide diversity indicated that the C. oryzae populations experienced rapid expansion after a "Bottleneck effect". The results of the mismatch distribution, neutrality test (Fu's Fs < 0, p < 0.001), and haplotype network analysis suggested that the population has recently undergone an expansion. Although genetic differentiation among C. oryzae populations was found to have existed at low/medium levels (Fst: 0.183 for COI, 0.065 for ITS1), the frequent gene flow presented as well (Nm: 2.23 for COI, 3.60 for ITS1) was supposed to be responsible for frequent local outbreaks.
RESUMO
Chlorops oryzae Matsumura is an important pest of rice plants throughout Asia, and has even become a major pest in some regions. Here, we present the complete mitogenome of C. oryzae for the first time. The complete mitogenome is 17,313 bp in length and contains 37 genes (13 protein-coding genes, 22 transfer RNAs, and two ribosomal RNAs) and a control region. The overall base composition is 42.04% for A, 37.18% for T, 12.59% for C, and 8.29% for G, with a bias toward A + T (79.22%). Protein-coding genes cox1 features an atypical ACG start codon and cox2, nad5, and nad4 have incomplete stop codons T or TA. All tRNA genes present the typical clover leaf secondary structure except trnS1 (AGN), where the DHU arm is replaced by a loop. Phylogeny showed that C. oryzae was placed as the basal lineage in Brachycera clade, and shared a closer relationship to Acalyptrate species.
RESUMO
Extended X-ray Absorption Fine Structure (EXAFS) has been one of the few structural probes available for crystalline, non-crystalline and even highly disordered specimens. However, the data analysis involves a patchy and tinkering process, including back-and-forth fitting and filtering, leading to ambiguous answers sometimes. Here we try to resolve this long standing problem, to extract the inter-atomic distances from the experimental data by a single step minimization, in order to replace the tedious and tinkering process. The new strategy is built firmly by the mathematical logic, and made straightforward and undeniable. The finding demonstrates that it is possible to break off from the traditional patchy model fitting, and to remove the logical confusion of a priori prediction of the structure to be matched with experimental data, making it a much more powerful technique than the existing methods. The new method is expected to benefit EXAFS users covering all disciplines. Also, it is anticipated that the current work to be the motivation and inspiration to the further efforts.
