Enhancement of fluorescence emission difference microscopy using conjugated vortex phase modulation

In this paper, we propose and demonstrate an improved fluorescence emission difference microscopy (FED) method, exploiting programmable phase modulation for image enhancement. The main novelty of the proposed approach lies in the matched size and intensity of two excitation spots. The proposed method improves the FED performance on image quality via artefact elimination. We demonstrate the feasibility of this method through theoretical studies and experimental tests. The experimental results of nanobeads and cells validate the practical performance of this method, which can enable reliable observations at superresolution in biomedical studies. LAY DESCRIPTION: In this paper, we propose a method to improve the imaging quality of regular fluorescence emission difference (FED) microscopy. In regular FED imaging, a solid and a doughnut excitation beam are successively used to acquire two images which are then subtracted with each other to improve the resolution of confocal microscopy. The doughnut beam can be generated by modulating the excitation beam with a vortex phase mask. Note that both of the excitation beam and the vortex phase mask must have the same handed direction in regular FED microscopy. However, some negative values may be produced and some information may be lost due to the subtraction process in regular FED imaging, which is mainly caused by the mismatched size and intensity of these two excitation spots. To address this issue, we propose conjugated FED (cFED) microscopy which additionally uses a conjugated vortex phase mask to modulate the solid beam to extend its focal spot size to be matched with the doughnut spot, which means the handed direction of the solid beam and the vortex phase mask is different. Besides, in order not to damage the resolution, the doughnut beam needs to be saturated to some degree. The experiment results show that, at the same resolution level, the negative values and the information loss in cFED image are all less than that of regular FED image.

Unique Heterogeneous Topological Pattern of the Metabolic Landscape in Rabbit Fetal Lungs following Tracheal Occlusion

INTRODUCTION

Fetal tracheal occlusion (TO) is currently an experimental approach to drive accelerated lung growth. It is stimulated by mechanotransduction that results in increased cellular proliferation and growth. However, it is currently unknown how TO affects the metabolic landscape of fetal lungs.

MATERIALS AND METHODS

TO or sham was performed on fetal rabbits at 26 days followed by lung harvest on day 30. Mass spectrometry was performed to evaluate global metabolic changes. Fluorescence lifetime intensity microscopy (FLIM) was performed to estimate local free/bound NADH relative ratio as an indicator of aerobic glycolysis versus oxidative phosphorylation (glycolysis/OXPHOS).

RESULTS

TO results in a metabolic shift from tricarboxylic acid cycle towards glycolysis. FLIM reveals uniform structures in control lungs characterized by similar ratios of free/bound NADH indicating a homogenous topological pattern. Similar uniform structures are observed in shams with some variability in the glycolysis/OXPHOS ratio. In contrast, lungs following TO demonstrate different types of unique distinct topological zones: one with enlarged alveoli and a shift towards glycolysis; the other maintains balance between glycolysis/OXPHOS similar to control lungs.

CONCLUSION

We demonstrate for the first time a unique variable topological pattern of metabolism in fetal lungs following TO with a wide variation of metabolism between zones.

Comparative Study for the Association of Mitochondrial Haplogroup F+ and Metabolic Syndrome between Longevity and Control Population in Guangxi Zhuang Autonomous Region, China

BACKGROUND

Our previous study suggested that mitochondrial haplogroup F (mtDNA F) was a longevity-associated biomarker, but the effect of mitochondrial haplogroup F on longevity individuals with metabolic syndrome (MetS) was not clear. Thus we explored the association between mtDNA F and MetS among longevity and control population in Guangxi Zhuang Autonomous Region, China.

METHOD

A total of 793 individuals consisting of 307 long-lived participants and 486 local healthy controls were involved in this study. Genotypes of mtDNA F were amplified by polymerase chain reaction and Sanger sequenced. MetS was defined according to the revised National Cholesterol Education Program's Adult Treatment Panel III (NCEP ATPIII ) criteria.

RESULTS

The prevalence of MetS in longevity group (28.0%) was higher than that (18.5%) in control group (P=0.002). Through the case-control stratify analysis, the prevalence of MetS in mtDNA F+ longevity individuals (29.8%) was 4.6 fold higher than that (5.3%) in local control group (P<0.001). However, after further longevity-only analysis, no association between MetS and mtDNA F+ in longevity group was observed (P=0.167). Following same analysis of two variables in control group, we found that the prevalence of MetS in mtDNA F- (95.8%) was higher than that in mtDNA F+ (5.3%); conversely, the prevalence of non-metabolic syndrome (NMetS) in mtDNA F+ (94.7%) was markedly higher than that in mtDNA F- (4.2%) (P<0.001).

CONCLUSION

We demonstrated that mtDNA F+ , as a molecuar biomarker, might not only confer beneficial effect to resistance against MetS but also function as a positive factor for long-life span among the population in Guangxi Zhuang Autonomous Region, China.

Cross-species hybridization of foot-and-mouth disease virus-infected BHK-21 cells using human and mouse oligonucleotide microarrays

Foot-and-mouth disease virus (FMDV) has a dual capacity to induce either acute or persistent infection in host animals. Establishment of an in vitro cell model of FMDV persistent infection facilitates the study of the mechanism underlying this type of infection. In this study, we analyzed gene expression profiles of both acute and persistent infections using cross-species microarrays. Our data suggest that human microarrays are more efficient than mouse microarrays in hybridization with cDNA from BHK-21 cells although the mouse is closer to the Syrian hamster in taxonomy. A set of differentially expressed genes (DEGs) that may be involved in the determination of acute or persistent infection was identified by using human or mouse microarrays. Seven common DEGs were found in both human and mouse arrays and showed similar fold changes. Among the DEGs, 33 genes were selected for further validation by using qRT-PCR and presented consistent results. The analysis of Gene Ontology Biological Processes indicated that various biosynthetic and metabolic processes were negatively regulated in the group of acute infection whereas multicellular organismal development processes were positively regulated in the group of persistent infection. Our study demonstrates the plausibility and utility of using cross-species microarrays to study FMDV-infected mammalian cells. The combined use of two types of microarrays can be more informative in exploring the mechanisms underlying the infections of FMDV.