Synaptic pruning mediated by glia in Alzheimer's disease / 药学学报

Alzheimer's disease (AD) is a neurodegenerative disease characterized by memory loss and cognitive impairment. To date, however, no disease-modifying strategies to prevent or cure AD exist. Synapses are involved in the connection of neurons and present as the key component for the memory and other neural activities. Synapse loss is a critical hallmark of AD pathology. In brain, glia cells, including microglia and astrocytes, are a group of highly specific cell types other than neurons. Microglia and astrocytes play a key role in maintaining the healthy neural circuit and regulating synaptic plasticity. Under development and physiological conditions, glial cells contribute to construct and maintain mature central neural networks via synaptic pruning. However, during AD pathogenesis, glial cells engulf synapses excessively, which leads to synapse loss, neuronal dysfunction, and cognitive impairment. Here, we review recent advances in our understanding of the underlying mechanisms for glia-mediated synaptic pruning in AD, and provide a novel strategy for the development of AD drugs.

The immunodominant and neutralization linear epitopes for SARS-CoV-2

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) becomes a tremendous threat to global health. Although vaccines against the virus are under development, the antigen epitopes on the virus and their immunogenicity are poorly understood. Here, we simulated the three-dimensional structures of SARS-CoV-2 proteins with high performance computer, predicted the B cell epitopes on spike (S), envelope (E), membrane (M), and nucleocapsid (N) proteins of SARS-CoV-2 using structure-based approaches, and then validated the epitope immunogenicity by immunizing mice. Almost all 33 predicted epitopes effectively induced antibody production, six of which were immunodominant epitopes in patients identified via the binding of epitopes with the sera from domestic and imported COVID-19 patients, and 23 were conserved within SARS-CoV-2, SARS-CoV and bat coronavirus RaTG13. We also found that the immunodominant epitopes of domestic SARS-CoV-2 were different from that of the imported, which may be caused by the mutations on S (G614D) and N proteins. Importantly, we validated that eight epitopes on S protein elicited neutralizing antibodies that blocked the cell entry of both D614 and G614 pseudo-virus of SARS-CoV-2, three and nine epitopes induced D614 or G614 neutralizing antibodies, respectively. Our present study shed light on the immunodominance, neutralization, and conserved epitopes on SARS-CoV-2 which are potently used for the diagnosis, virus classification and the vaccine design tackling inefficiency, virus mutation and different species of coronaviruses.

Hydrogen photoproduction from acetate by Rhodopseudomonas palustris / 生物工程学报

Based on the characteristics of metabolism of photosynthetic bacteria and the major kinds of organic compounds produced in wastewater degradation, eleven kinds of organic compounds were chosen for hydrogen photoproduction using Rhodopseudomonas palustris Z strain. The maximal volumetric H2 productivity was obtained using acetate as the sole carbon source and electron donor. The kinetics of cell growth and H2 liberation, and the influences of several major limiting factors on photoevolution of H2 were examined using acetate as carbon source. It was shown that hydrogen production was partially correlated with cell growth. The medium composition of the preculture, the preculture time, and inoculation volume were confirmed to have big effects on hydrogen photoevolution. The time delay of H2 production was evidently shortened using the inoculum of late exponential growth phase or stationary phase using ammonium sulfate as nitrogen source or with the inoculum of middle exponential growth phase using glutamate as the nitrogen source. The identity of temperature and light intensity for H2 evolution and cell growth has significant potential application in the technology of splitting organic acid into H2 by photosynthetic bacteria. The concentrations of acetate and glutamate in the medium affected hydrogen photoevolution and cell growth significantly. The productivity of H2 increased with substrate concentrations when substrate concentrations of sodium acetate and sodium glutamate were lower than 70 mmol/L and 15 mmol/L, respectively. Hydrogen production was inhibited but the cell growth was faster when the concentration of sodium glutamate over 15 mmol/L due to forming free NH4+. The highest rate of hydrogen production was 19.4 mL.L-1.h-1 using 30 mmol/L of sodium acetate as hydrogen donor under the standard conditions, respectively. The optimal conditions for hydrogen production were 35-37 degrees C, 6000-8000 lx and pH 7.3-8.3. The effects of oxygen and inoculation volume on photoproduction of hydrogen were also discussed.

SCREENING OF STRAINS PRODUCING LIPASES WITH HIGH ACTIVITIES AND CONSTRUCTION OF STRAIN LIBRARY / 微生物学通报

More than 80 strains producing lipases were screened from oily soil of vegetable oil plant, meat processing factory and dairy factory in Jinan city, Shandong Province, which included bacteria, moulds and yeast. Conditions for lipase production and properties of some enzymes were studied. One drug-resistant mutant strain Y-11 with higher lipase activity was from Trichosporon sp. Y-1. In addition, Optimization of lipase production and characterization of enzymes were carried out. On the basis of above experiments, a characteristic library of stains producing lipases was established.