Culturable bacterial diversity in hypolithic and peripheral soils in the west of the Hexi Corridor desert and its influencing factors

Microbes inhabiting the desert respond sensitively to environmental changes and may be an indicator for changes in the desert ecosystem.Hypolithic microbial communities in the desert play a vital role in ecosystem processes such as soil formation and organic matter accumulation.This study investigated and compared the culturable bacterial community structure and diversity in hypolithic and peripheral soils,and the interaction between bacteria and environmental factors.The bacteria were isolated using four different kinds of media and identified by 16S rRNA gene-sequence analysis.The numbers of culturable bacteria in the hypolithic and peripheral soils ranged from 3.0×104 to 3.6×105 CFU/g and from 6.5×104 to 5.3×105 CFU/g,respectively,indicating that the bacteria number in peripheral soil was higher than that in hypolithic soil.A total of 98 species belonging to 34 genera were identified,among which Arthrobacter,Bacillus,and Streptomyces were found dominantly and widely distributed.The community of culturable bacteria had obvious sample specificity,and the diversity in hypolithic soil was higher than that in peripheral soil.On the regional scale,the distribution of culturable bacteria and the environmental factors showed regular changes.On the local scale,the high heterogeneity of the hypolithic environment determined the specificity of the number and species of culturable bacteria.

Isolation and characterization of Bordetella pseudohinzii in mice in China

We report on the first detection and isolation of B.pseudohinzii(Bordetella pseudohinzii)in laboratory mice in China.Forty‐one B.pseudohinzii strains were isolated from 3094 mice in 33 different laboratory animal facilities in southern China.The isolates were identified through culture and genome sequenceing.Phylogenetic analysis based on the sequences of 16S rRNA and OmpA genes demonstrated that these strains were on the same clade as other B.pseudohinzii strains isolated from mice.Experimental infected mice presented an asymptomatic infection.B.pseudohinzii replicated in both the respiratory tract and the digestive tract.Most importantly B.pseudohinzii shed via feces and infected a group of sentinel mice in a separate cage via cage padding contaminated with B.pseudohinzii‐positive feces,indicating that B.pseudohinzii could transmit efficiently among mice and contaminate environmental facilities.Our study highlights the importance of routine monitoring of the pathogen in laboratory mice and provides vital insights into the transmission of Brodetellae in rodents and human.

Orange-red, green, and blue fiuorescence carbon dots for white light emitting diodes

Fluorescent carbon dots(CDs) are admirable nanomaterials due to their superior optical properties and low cost.However,regulation of the emission colors in CDs for lighting device still remains a challenge.In this work,we developed a green hydrothermal method to obtain three emission colors of CDs using L-tyrosine(for blue CDs),o-phenylendiamine(for green CDs) and L-tyrosine/o-phenylendiamine mixture(for orange-red CDs).These CDs possess good water dispersibility,strong emission with high quantum yields,and excellent photostability.Furthermore,the resulting CDs were dispersed in polyvinyl alcohol(PVA) matrix to yield solid state films,where the self-quenching effect in solid state was effectively avoided.A full-color light-emitting diode was fabricated by packing the CDs-PVA composites on the top of a UV-chip,which have superior potential applications in CDs-based solid-state lighting system.

染色质结构稳定蛋白4的下调诱导肿瘤细胞进入滞育样状态:乳酸化及胞质分裂的协同调控

胚胎滞育是许多哺乳动物面对恶劣环境时采取的一种生存策略.这种策略通过暂时停止胚胎的发育来提高在恶劣条件下的生存能力.在这种情况下,胚胎的增殖被抑制,着床过程被延迟.Dhimole等人[1]最近的一项研究表明,肿瘤细胞在受到细胞毒性药物治疗时,会转变成类似于滞育状态,从而减少药物引起的细胞死亡.

Field-portable ratiometric fluorescence imaging of dual-color label-free carbon dots for uranyl ions detection with cellphone-based optical platform

Under the public spotlight,uranyl(UO22+)ions has attracted considerable attention for the extreme radioactive and chemical toxicity to ourselves and our environment.Herein,we present a simple and effective ratiometric fluorescence imaging method for the visualizing and quantitative detection UO22+ions by cellphone-based optical platform.The sensing solution was prepared by mixing label-free red carbon dots(r-CDs)and blue carbon dots(b-CDs)together with a fixed photoluminescence intensity ratio of 4:1.When UO22+ions were added,the fluorescence of r-CDs can be selectively quenched,while the fluorescence of b-CDs remains stable without spectral cha nges.With the gradually increase the amounts of UO22+ions,the different response of dual-color CDs resulted in a signification color evolution from deep red to dark purple under the ultraviolet(UV)light illumination.Then,a cellphone-based optical platform was constructed for directly imaging the color change of the samples,and the built-in Colorpicker APP quickly output the red,green and blue(RGB)channel values of these images within one second.Interesting,there was a linear relationship between the ratio of red and blue(R/B)channel values and UO22+ions concentration from 0μmol/L to 30.0μmol/L(R^2=0.92804)with the detection limit of^8.15μmol/L(signal-to-noise ratio of 3).In addition,the optical platform has also been applied to the quantification of UO22+ions in tap water and river water sample.With the advantage of low-cost,portable,easy to operation,we anticipate that this method would greatly improve the accessibility of UO22+ions detection even in resource-limited areas.