The neuronal stem cell of the olfactory epithelium

The vertebrate olfactory epithelium (OE) is a system in which behavior of neuronal progenitor cells can be observed and manipulated easily. It is morphologically and functionally similar to embryonic germinal neuroepithelia, but is simpler in that it produces large numbers of a single type of neuron, the olfactory receptor neuron (ORN). The OE is amenable to tissue culture, gene transfer, and in vivo surgical approaches, and these have been exploited in experiments aimed at understanding the characteristics of OE neuronal progenitor cells. This has led to the realization that the ORN lineage contains at least three distinct stages of proliferating neuronal progenitor cells (including a stem cell), each of which represents a point at which growth control can be exerted. Neurogenesis proceeds continually in the OE, and studies in vivo have shown that this is a regulated process that serves to maintain the number of ORNs at a particular level. These studies suggest that OE neuronal progenitors—which are in close physical proximity to ORNs—can “read” the number of differentiated neurons in their environment and regulate production of new neurons accordingly. Putative neuronal stem cells of the OE have been identified in vitro, and studies of these cells indicate that ORNs produce a signal that feeds back to inhibit neurogenesis. This inhibitory signal may be exerted at the level of the stem cell itself. Recent studies to identify this signal, as well as endogenous stimulatory signals that may be important in regulating OE neurogenesis, are also discussed. © 1998 John Wiley & Sons, Inc. J Neurobiol 36: 190–205, 1998     

Diversification of mitogenomes in three sympatric Altica flea beetles (Insecta,Chrysomelidae)

The Asian flea beetles Altica cirsicola, Altica fragariae and Altica viridicyanea are broadly sympatric and morphologically highly similar but feed on distantly related host plants. They have been suggested as a model for ecological speciation studies. However, their phylogeny and species limits remain uncertain. In this study, we added mitochondrial genomes from multiple individuals of each species to the growing database. Phylogenetic analyses based on 15 genes showed clear interspecific divergences of A. fragariae from the other species, but A. cirsicola and A. viridicyanea were not distinguishable by distance‐based or tree‐based methods of species delimitation due to non‐monophyly of mitogenomes relative to the morphologically defined entities, possibly affected by interspecific introgression. This was confirmed by wider sampling of mitochondrial COX1 (58 individuals) and the second internal transcribed spacer of nuclear ribosomal RNA cluster (ITS2; 68 individuals), which showed that ITS2, but not COX1, coincided with the morphological species limits. The full mitochondrial genomes are not able to shed further light on the species status, even with the most sensitive approach based on diagnostic characters, yet the whole mitogenome is useful to get improved estimates of intra‐ and interspecific variation, not affected by the stochastic error seen in individual genes.     

Validity and reliability of Raman spectroscopy for carotenoid assessment in cattle skin

Carotenoids are powerful antioxidants capable of helping to protect the skin from the damaging effects of exposure to sun by reducing the free radicals in skin produced by exposure to ultraviolet radiation, and they may also have a physical protective effect in human skin. Since carotenoids are lipophilic molecules which can be ingested with the diet, they can accumulate in significant quantities in the skin. Several studies on humans have been conducted to evaluate the protective function of carotenoids against various diseases, but there is very limited published information available to understand the mechanism of carotenoid bioavailability in animals. The current study was conducted to investigate the skin carotenoid level (SCL) in two cattle skin sets – weaners with an unknown feeding regime and New Generation Beef (NGB) cattle with monitored feed at three different ages. Rapid analytical and sensitive Raman spectroscopy has been shown to be of interest as a powerful technique for the detection of carotenoids in cattle skin due to the strong resonance enhancement with 532 nm laser excitation. The spectral difference of both types of skin were measured and quantified using univariate and linear discriminant analysis. SCL was higher in NGB cattle than weaners and there is a perfect classification accuracy between weaners and NGB cattle skin using carotenoid markers as a basis. Further work carried out on carotenoid rich NGB cattle skin of 8, 12 and 24 months of age identified an increasing trend in SCL with age. The present work validated the ability of Raman spectroscopy to determine the skin carotenoid level in cattle by comparing it with established HPLC methods. There is an excellent correlation of R² = 0.96 between the two methods that could serve as a model for future application for larger population studies.     

Multiple telophase arrest bypassed (tab) mutants alleviate the essential requirement for Cdc15 in exit from mitosis in S. cerevisiae

Background  

The Mitotic Exit Network (MEN) proteins – including the protein kinase Cdc15 and the protein phosphatase Cdc14 – are essential for exit from mitosis in Saccharomyces cerevisiae. To identify downstream targets of the MEN, we sought telophase arrest bypassed (tab) mutations that bypassed the essential requirement for CDC15. Previous studies identified net1 ^tab2-1 and CDC14 ^TAB6-1 as mutations in the RENT complex subunits Net1 and Cdc14, respectively, and revealed that the MEN acts by promoting release of Cdc14 from its nucleolar Net1 anchor during anaphase. However, the remaining tab mutants were not characterized.     

RT—PCR法检测大鼠脑组织及C6细胞中β—APP的表达

β-淀粉样蛋白(β-AP)是阿尔茨海默氏病(Alzheimer’s disease)病人老年斑的主要成分,它是β-淀粉样前体蛋白(β-APP)剪切后的产物。β-APP基因在体内存在β-APP_(695),β-APP_(751)β-APP_(770)。等几种主要的转录物,它们的区别在于Kunize丝氨酸蛋白酶抑制区(KDI)编码序列的存在和缺失。通过RT-PCR技术,用针对KPI编码区两侧序列的一种特异性引物可由总RNA样品中扩增出反映以上三种转录物的cDNA片段。实验表明,胎鼠脑组织中未检测到β-APPmRNA;6月龄大鼠海马组织,大脑皮层中只检测到β-APP_(695);在神经胶质瘤细胞系C6中存在β-APP_(695),β-APP_(751),β-APP_(770),其中β-APP_(770)占优势。     

Attitudes toward COVID-19 vaccines in Chinese college students

Background: Vaccination is an important preventative measure against the coronavirus disease 19 (COVID-19) pandemic. To implement vaccination and immunization programs effectively, it is essential to investigate public attitudes toward COVID-19 vaccines. This study examined the attitudes of Chinese college students toward COVID-19 vaccines and their associated factors. Methods: A cross-sectional study was conducted in college students nationwide from December 27, 2020 to January 18, 2021. Attitudes toward COVID-19 vaccines and acceptance of future vaccination programs were assessed. Results: Totally, 2,881 college students participated in this survey; of them, 76.3% (95% CI: 74.8% - 77.9%) were willing to accept a COVID-19 vaccine in the future. Multiple logistic analysis revealed that students living in urban (OR=1.409, 95% CI: 1.152 - 1.724, p=0.001) and those studying health-related courses (OR=1.581, 95% CI: 1.291 - 1.935, p<0.001) were more likely to have a positive attitude toward COVID-19 vaccines. In addition, those who were worried about being infected with COVID-19 (very much vs no, OR=1.690, 95% CI: 1.212-2.356, p=0.002), heard previously about COVID-19 vaccines (OR=1.659, 95% CI: 1.268-2.170, p<0.001), believed that vaccines are safe (Yes vs No, OR=3.570, 95% CI: 1.825-6.980), thought that vaccines can protect people from being infected with COVID-19 (Yes vs No, OR=1.957, 95% CI: 1.286-2.979, p=0.002), and had encouraged their family and friends to have a vaccine (Yes vs No, OR=17.745, 95% CI: 12.271-25.660, p<0.001) had higher acceptance of COVID-19 vaccination. Conclusions: A high rate of acceptance of COVID-19 vaccines was found among Chinese college students. However, vaccine uptake may be reduced by concerns about vaccine safety and efficacy. Alleviating these concerns and enhancing public confidence in vaccines are crucial for future immunization programs against the COVID-19 pandemic.     

Protein restriction and cancer

Protein restriction without malnutrition is currently an effective nutritional intervention known to prevent diseases and promote health span from yeast to human. Recently, low protein diets are reported to be associated with lowered cancer incidence and mortality risk of cancers in human. In murine models, protein restriction inhibits tumor growth via mTOR signaling pathway. IGF-1, amino acid metabolic programing, FGF21, and autophagy may also serve as potential mechanisms of protein restriction mediated cancer prevention. Together, dietary intervention aimed at reducing protein intake can be beneficial and has the potential to be widely adopted and effective in preventing and treating cancers.     

Circadian orchestration of host and gut microbiota in infection

Circadian rhythms are present in almost every organism and regulate multiple aspects of biological and physiological processes (e.g. metabolism, immune responses, and microbial exposure). There exists a bidirectional circadian interaction between the host and its gut microbiota, and potential circadian orchestration of both host and gut microbiota in response to invading pathogens. In this review, we summarize what is known about these intestinal microbial oscillations and the relationships between host circadian clocks and various infectious agents (bacteria, fungi, parasites, and viruses), and discuss how host circadian clocks prime the immune system to fight pathogen infections as well as the direct effects of circadian clocks on viral activity (e.g. SARS-CoV-2 entry and replication). Finally, we consider strategies employed to realign normal circadian rhythmicity for host health, such as chronotherapy, dietary intervention, good sleep hygiene, and gut microbiota-targeted therapy. We propose that targeting circadian rhythmicity may provide therapeutic opportunities for the treatment of infectious diseases.