A flow cytometer based protocol for quantitative analysis of bloom-forming cyanobacteria (Microcystis) in lake sediments

A quantitative protocol for the rapid analysis of Microcystis cells and colonies in lake sediment was developed using a modified flow cytometer, the CytoSense. For cell enumeration, diluted sediment samples containing Microcystis were processed with sonication to disintegrate colonies into single cells. An optimized procedure suggested that 5 mg dw (dry weight)/mL dilution combined with 200 W x 2 min sonication yielded the highest counting efficiency. Under the optimized determination conditions, the quantification limit of this protocol was 3.3x10(4) cells/g dw. For colony analysis, Microcystis were isolated from the sediment by filtration. Colony lengths measured by flow cytometry were similar to those measured by microscopy for the size range of one single cell to almost 400 mu m in length. Moreover, the relationship between colony size and cell number was determined for three Microcystis species, including Microcystis flos-aquae, M. aeruginosa and M. wessenbergii. Regression formulas were used to calculate the cell numbers in different-sized colonies. The developed protocol was applied to field sediment samples from Lake Taihu. The results indicated the potential and applicability of flow cytometry as a tool for the rapid analysis of benthic Microcystis. This study provided a new capability for the high frequency monitoring of benthic overwintering and population dynamics of this bloom-forming cyanobacterium.A quantitative protocol for the rapid analysis of Microcystis cells and colonies in lake sediment was developed using a modified flow cytometer, the CytoSense. For cell enumeration, diluted sediment samples containing Microcystis were processed with sonication to disintegrate colonies into single cells. An optimized procedure suggested that 5 mg dw (dry weight)/mL dilution combined with 200 W x 2 min sonication yielded the highest counting efficiency. Under the optimized determination conditions, the quantification limit of this protocol was 3.3x10(4) cells/g dw. For colony analysis, Microcystis were isolated from the sediment by filtration. Colony lengths measured by flow cytometry were similar to those measured by microscopy for the size range of one single cell to almost 400 mu m in length. Moreover, the relationship between colony size and cell number was determined for three Microcystis species, including Microcystis flos-aquae, M. aeruginosa and M. wessenbergii. Regression formulas were used to calculate the cell numbers in different-sized colonies. The developed protocol was applied to field sediment samples from Lake Taihu. The results indicated the potential and applicability of flow cytometry as a tool for the rapid analysis of benthic Microcystis. This study provided a new capability for the high frequency monitoring of benthic overwintering and population dynamics of this bloom-forming cyanobacterium

Anti-Proliferation and Anti-Invasion Effects of Diosgenin on Gastric Cancer BGC-823 Cells with HIF-1α shRNAs

Drug resistance is a major factor for the limited efficacy of chemotherapy in gastric cancer treatment. Hypoxia-inducible factor-1α (HIF-1α), a central transcriptional factor in hypoxia, is suggested to participate in the resistance. Here, we identified a hypoxia-mimic (cobalt chloride) sensitive gastric cell line BGC-823 to explore whether diosgenin, an aglycone of steroidal saponins, can inhibit cancer cell invasion and survival of solid tumor in a hypoxic mimic microenvironment. We have shown that diosgenin is a potent candidate for decreasing the ability of invasion and survival in cobalt chloride treated BGC-823 cells. In addition, when combined with HIF-1α specific short hairpin RNA (shRNA), diosgenin can inhibit BGC-823 cells more effectively. The anti-invasion role of diosgenin may be related to E-cadherin, integrinα5 and integrin β6. These results suggest that diosgenin may be a useful compound in controlling gastric cancer cells in hypoxia condition, especially when combined with down-regulated HIF-1α

Mesaconine alleviates doxorubicin-triggered cardiotoxicity and heart failure by activating PINK1-dependent cardiac mitophagy

Aberrant mitophagy has been identified as a driver for energy metabolism disorder in most cardiac pathological processes. However, finding effective targeted agents and uncovering their precise modulatory mechanisms remain unconquered. Fuzi, the lateral roots of Aconitum carmichaelii, shows unique efficacy in reviving Yang for resuscitation, which has been widely used in clinics. As a main cardiotonic component of Fuzi, mesaconine has been proven effective in various cardiomyopathy models. Here, we aimed to define a previously unrevealed cardioprotective mechanism of mesaconine-mediated restoration of obstructive mitophagy. The functional implications of mesaconine were evaluated in doxorubicin (DOX)-induced heart failure models. DOX-treated mice showed characteristic cardiac dysfunction, ectopic myocardial energy disorder, and impaired mitophagy in cardiomyocytes, which could be remarkably reversed by mesaconine. The cardioprotective effect of mesaconine was primarily attributed to its ability to promote the restoration of mitophagy in cardiomyocytes, as evidenced by elevated expression of PINK1, a key mediator of mitophagy induction. Silencing PINK1 or deactivating mitophagy could completely abolish the protective effects of mesaconine. Together, our findings suggest that the cardioprotective effects of mesaconine appear to be dependent on the activation of PINK1-induced mitophagy and that mesaconine may constitute a promising therapeutic agent for the treatment of heart failure

Distributed evolutionary algorithms and their models: A survey of the state-of-the-art

The increasing complexity of real-world optimization problems raises new challenges to evolutionary computation. Responding to these challenges, distributed evolutionary computation has received considerable attention over the past decade. This article provides a comprehensive survey of the state-of-the-art distributed evolutionary algorithms and models, which have been classified into two groups according to their task division mechanism. Population-distributed models are presented with master-slave, island, cellular, hierarchical, and pool architectures, which parallelize an evolution task at population, individual, or operation levels. Dimension-distributed models include coevolution and multi-agent models, which focus on dimension reduction. Insights into the models, such as synchronization, homogeneity, communication, topology, speedup, advantages and disadvantages are also presented and discussed. The study of these models helps guide future development of different and/or improved algorithms. Also highlighted are recent hotspots in this area, including the cloud and MapReduce-based implementations, GPU and CUDA-based implementations, distributed evolutionary multiobjective optimization, and real-world applications. Further, a number of future research directions have been discussed, with a conclusion that the development of distributed evolutionary computation will continue to flourish

Synthesis of Isoxazoline-Functionalized Phenanthridines via Iminoxyl Radical-Participated Cascade Sequence

Readily accessible β,γ-unsaturated ketoximes reacted with 2-arylphenylisonitriles under the conditions of <i>t</i>-BuOOH and <i>n</i>-Bu₄NI to give isoxazoline functionalized phenanthridines via tandem intramolecular/intermolecular C–O/C–C/C–C bond formation. The reaction involves the initial generation of iminoxyl radicals from the oxidation of β,γ-unsaturated ketoximes by <i>t</i>-BuOOH and <i>n</i>-Bu₄NI followed a cascade radical cyclization/addition/cyclization sequence