Stock Assessment Using the LBB Method for Portunus trituberculatus Collected from the Yangtze Estuary in China

Portunus trituberculatus is an important invertebrate species distributed in the Yangtze Estuary. However, its biomass and enrichment have been affected seriously by ongoing human activity in recent decades. The length-based Bayesian biomass estimator (LBB) is a novel and potent method to estimate the stocks for most commercial fishes and invertebrates in offshore using only length and frequency data. In this study, the results showed that the ratio of current exploited biomass relative to unexploited biomass (B/B0) was smaller than relative biomass capable of producing maximum sustainable yields (BMSY/B0) after handling of the catches of the P. trituberculatus collected from the Yangtze Estuary in 2018 using the LBB method. Therefore, this evidence indicated that the biomass of the swimming crab was relatively low as a result of the overfishing in this water area and the catches of the crabs should be controlled at a reasonable level in the future. Meanwhile, LBB is a promising method providing a theoretical basis for the management and protection of fishery resources

Genetic Diversity and Population Structure of <i>Portunus</i><i>trituberculatus</i> in Released and Wild Populations Based on Microsatellite DNA Markers from the Yangtze Estuary

Portunus trituberculatus is an important economic species of crab that is artificially bred and released in the Yangtze River Estuary and its adjacent sea areas. Based on six microsatellite markers, we investigate the genetic diversity and structure of 101 P. trituberculatus specimens collected from two hatcheries in Nantong and Zhoushan that participated in stock enhancement in the year 2019. We compared these with 124 wild specimens caught from 13 localities in the estuary. Analysis of several genetic diversity parameters (NA, RS, I, HO, HE, FIS, and FST) for the 15 populations demonstrates that both released and wild populations possess relatively rich genetic diversity. Furthermore, the released groups demonstrate no less genetic variation between themselves than do the wild crabs. Most FIS values are greater than zero, which shows inbreeding is common among specimens with geographically open sites. However, insufficient sampling may have led to a wide distribution of null alleles, a Hardy–Weinberg test disequilibrium in microsatellite markers PN22 and P04, and a lack of crab genetic diversity in site 14. All populations (except locality 14) have not suffered the bottleneck effect. Four subgroups can be seen to roughly spread longitudinally along the sample area by performing pairwise comparisons of genetic distance and FST values among the populations. No obvious topological heterogeneity is discovered among the four subgroups in a phylogenetic tree. The existence of genetic exchange and differentiation among the subgroups is also verified using structure analysis. Therefore, based on this evidence, we propose that the hatchery stock enhancements performed in Nantong and Zhoushan result in no reduction in genetic diversity for wild populations in the Yangtze Estuary in 2019

Synergistic Effect of Fluconazole and Calcium Channel Blockers against Resistant <i>Candida albicans</i>

<div><p>Candidiasis has increased significantly recently that threatens patients with low immunity. However, the number of antifungal drugs on the market is limited in comparison to the number of available antibacterial drugs. This fact, coupled with the increased frequency of fungal resistance, makes it necessary to develop new therapeutic strategies. Combination drug therapy is one of the most widely used and effective strategy to alleviate this problem. In this paper, we were aimed to evaluate the combined antifungal effects of four CCBs (calcium channel blockers), amlodipine (AML), nifedipine (NIF), benidipine (BEN) and flunarizine (FNZ) with fluconazole against <i>C</i>. <i>albicans</i> by checkerboard and time-killing method. In addition, we determined gene (<i>CCH1</i>, <i>MID1</i>, <i>CNA1</i>, <i>CNB1</i>, <i>YVC1</i>, <i>CDR1</i>, <i>CDR2</i> and <i>MDR1</i>) expression by quantitative PCR and investigated the efflux pump activity of resistant <i>candida albicans</i> by rhodamine 6G assay to reveal the potential mechanisms. Finally, we concluded that there was a synergy when fluconazole combined with the four tested CCBs against resistant strains, with fractional inhibitory concentration index (FICI) <0.5, but no interaction against sensitive strains (FICI = 0.56 ~ 2). The mechanism studies revealed that fluconazole plus amlodipine caused down-regulating of <i>CNA1</i>, <i>CNB1</i> (encoding calcineurin) and <i>YVC1</i> (encoding calcium channel protein in vacuole membrane).</p></div

Relative expression of <i>CNA1</i>, <i>CNB1</i> and <i>YVC1</i> following treatment with fluconazole (FLC) and amlodipine (AML) alone or in combination in CA10.

<p>Cells were treated with fluconazole at 1 μg ml^-1, amlodipine at 16 μg ml^-1 alone or in combination. Total RNA was extracted and reversely transcribed to cDNA. cDNA was then used for real-time quantitative PCR to detect expression levels of <i>CNA1</i>, <i>CNB1</i> and <i>YVC1</i>. Values represent the means ± standard deviation of three replicates. * P < 0.01 and at least 2.0-fold compared to the control group.</p

Gene-specific primers used for RealTime-PCR.

<p>Gene-specific primers used for RealTime-PCR.</p

The combined antifungal effects of fluconazole with calcium channel blockers against resistant <i>Candida albicans</i> evaluated by FICI.

<p>The combined antifungal effects of fluconazole with calcium channel blockers against resistant <i>Candida albicans</i> evaluated by FICI.</p

Three-dimensional plots of fluconazole combined with tested calcium channel blockers against CA10 (resistant) using the MATLAB program.

<p>The ΔE values obtained for each combination can be depicted on the z axis to construct a 3D surface plot. Peaks above and below the 0 plane indicate synergistic and antagonistic combinations, respectively. The 0 plane indicates the absence of SS interaction. The color-coding on the right indicates that the closer to red in the top of the bar, the more effective the drug combinations.</p