RESUMO
Coupled with geological and geographical history, climatic oscillations during the Pleistocene period had remarkable effects on species biodiversity and distribution along the northwestern Pacific. To detect the population structure and demographic history of Odontamblyopuslacepedii, 547-bp fragments of the mitochondrial DNA control region were sequenced. A low level of nucleotide diversity (0.0065 ± 0.0037) and a high level of haplotype diversity (0.98 ± 0.01) was observed. The Maximum Likelihood (ML) and Bayesian Inference phylogenetic trees showed no significant genealogical structure corresponding to sampling locations. The results of AMOVA and pairwise F ST values revealed some significant genetic differentiation among populations, and the isolation by distance (IBD) analysis supported that the genetic differentiation was associated with the geographic distances. The demographic history of O.lacepedii examined by neutrality tests, mismatch distribution analysis, and Bayesian Skyline Plots (BSP) analysis suggested a sudden population expansion, and the expansion time was estimated to be around the Pleistocene. We hypothesize that the climate changes during the Pleistocene, ocean currents, and larval dispersal capabilities have played an important role in shaping contemporary phylogeographic pattern and population structure of O.lacepedii.
RESUMO
Species distribution monitoring and biomass assessment are crucial for fishery management and resource conservation. However, traditional methods such as motor trawling are costly and less effective than the novel environmental DNA (eDNA) approach. This study employs eDNA approach to investigate horizontal and vertical distributions of small yellow croaker (Larimichthys polyactis), an economically important species, in the East China Sea. The analysis of 171 eDNA samples collected from 44 stations using the species-specific primers and Taqman probe suggests a presence of small yellow croaker at 28 sampling layers in 44 stations. Significant differences in croaker eDNA concentrations were revealed among sampling stations and layers, consistent with previous findings through motor-trawl capture offshore and nearshore ichthyoplakton surveys, indicating small yellow croaker exhibits strong regional distribution and layer preference. In addition, we found a high eDNA concentration of small yellow croaker in the surface waters beyond the motor-trawl prohibition line, which confirms spawning grounds have been expanded from nearshore to offshore areas. Such expansion of spawning grounds could be a response by small yellow croaker to stressors such as overfishing, climate change, and nearshore environment contamination. To identify environmental variables potentially associated with small yellow croaker presence and absence, we conducted a correlation analysis between eDNA concentration and environmental variables, and the results provide a guideline for further investigation of fishery resources in the future. In conclusion, this study demonstrates the power of the eDNA approach in monitoring small yellow croaker at extensive geographic scales. The developed protocols and the findings are expected to assist in long-term monitoring and protection programs and benefit sustainable fishery in small yellow croaker.
Assuntos
Conservação dos Recursos Naturais , DNA Ambiental/isolamento & purificação , Monitorização de Parâmetros Ecológicos/métodos , Pesqueiros/estatística & dados numéricos , Perciformes/genética , Distribuição Animal , Animais , China , Estudos de Viabilidade , Água do Mar/químicaRESUMO
Let [Formula: see text] be nonnegative matrices. In this paper, some upper bounds for the spectral radius [Formula: see text] are proposed. These bounds generalize some existing results, and comparisons between these bounds are also considered.
RESUMO
Estrogen receptor (ER) and progesterone receptor (PR) overexpression can be used to predict patient prognosis in breast cancer (BC). Human epidermal growth factor receptor 2 (HER2) is a reliable predictive marker in invasive breast cancer (IBC). Thin-Prep (TP) specimens are commonly utilized for immunocytochemistry (ICC) in fine needle aspiration cytology (FNAC). Thus, we sought to investigate if the incorporation of molecular diagnosis performed on TP-processed specimens is applicable in clinical practice. Hormone receptors (HRs) and HER2 immunocytochemistry was performed on 542 primary breast cancer FNAC specimens using the TP method. One hundred fourteen HER2 fluorescence in situ hybridization (FISH) analyses were performed on HER2 ICC 2+ FNAC specimens and the corresponding tissue samples. HRs results of TP slides and those of formalin-fixed paraffin-embedded (FFPE) slides were correlated well for ER (concordance rate =â 3.3%, kappa value = 0.85) and PR (concordance rate = 88.6%, kappa value = 0.75). HER2 results for the TP slides and those of the matched FFPE slides also correlated well (concordance rate = 80.0%, kappa value = 0.62). The specificity of HER2 was 97.3%; however, the sensitivity was only 67.1%. Cytological specimens and histological samples showed a strong correlation (concordance rate = 99.1%, kappa value = 0.98) while being used to evaluate HER2 gene amplification. FNAC is a minimally invasive technique that can be used as an alternative method to collect tissue especially in cases where an excisional or core biopsy is difficult to obtain, or when recurrence is present. The results of ICC HRs in FNAC TP specimens may be used instead, but HER2 assessment may not be reliable enough for clinical use. FISH testing is necessary in this setting.