Construction of Yeast One-Hybrid Library of Alternaria oxytropis and Screening of Transcription Factors Regulating swnK Gene Expression.

The indolizidine alkaloid-swainsonine (SW) is the main toxic component of locoweeds and the main cause of locoweed poisoning in grazing animals. The endophytic fungi, Alternaria Section Undifilum spp., are responsible for the biosynthesis of SW in locoweeds. The swnK gene is a multifunctional complex enzyme encoding gene in fungal SW biosynthesis, and its encoding product plays a key role in the multistep catalytic synthesis of SW by fungi using pipecolic acid as a precursor. However, the transcriptional regulation mechanism of the swnK gene is still unclear. To identify the transcriptional regulators involved in the swnK gene in endophytic fungi of locoweeds, we first analyzed the upstream non-coding region of the swnK gene in the A. oxytropis UA003 strain and predicted its high transcriptional activity region combined with dual-luciferase reporter assay. Then, a yeast one-hybrid library of A. oxytropis UA003 strain was constructed, and the transcriptional regulatory factors that may bind to the high-transcriptional activity region of the upstream non-coding region of the swnK gene were screened by this system. The results showed that the high transcriptional activity region was located at -656 bp and -392 bp of the upstream regulatory region of the swnK gene. A total of nine candidate transcriptional regulator molecules, including a C2H2 type transcription factor, seven annotated proteins, and an unannotated protein, were screened out through the Y1H system, which were bound to the upstream high transcriptional activity region of the swnK gene. This study provides new insight into the transcriptional regulation of the swnK gene and lays the foundation for further exploration of the regulatory mechanisms of SW biosynthesis in fungal endophytic locoweeds.

Alterations of microbiota and metabolites in the feces of calves with diarrhea associated with rotavirus and coronavirus infections.

The changes in the composition of intestinal microbiota and metabolites have been linked to digestive disorders in calves, especially neonatal calf diarrhea. Bovine rotavirus (BRV) and bovine coronavirus (BCoV) are known to be the primary culprits behind neonatal calf diarrhea. In this study, we analyzed changes in the fecal microbiota and metabolites of calves with neonatal diarrhea associated with BRV and BCoV infection using high-throughput 16S rRNA sequencing and metabolomics technology. The microbial diversity in the feces of calves infected with BRV and BCoV with diarrhea decreased significantly, and the composition changed significantly. The significant increase of Fusobacterium and the reductions of some bacteria genera, including Faecalibacterium, Bifidobacterium, Ruminococcus, Subdoligranulum, Parabacteroides, Collinsella, and Olsenella, etc., were closely related to diarrhea associated with BRV and BCoV infection. Metabolites in the feces of BRV and BCoV-infected calves with diarrhea were significantly changed. Phosphatidylcholine [PC; 16:1(9 Z)/16:1(9 Z)], lysophosphatidylethanolamine (LysoPE; 0:0/22:0), lysophosphatidylcholine (LysoPC; P-16:0) and LysoPE (0:0/18:0) were significantly higher in the feces of BRV-infected calves with diarrhea. In contrast, some others, such as desthiobiotin, were significantly lower. BRV infection affects glycerophospholipid metabolism and biotin metabolism in calves. Two differential metabolites were significantly increased, and 67 differential metabolites were significantly reduced in the feces of BCoV-infected calves with diarrhea. Seven significantly reduced metabolites, including deoxythymidylic acid (DTMP), dihydrobiopterin, dihydroneopterin triphosphate, cortexolone, cortisol, pantetheine, and pregnenolone sulfate, were enriched in the folate biosynthesis, pantothenate and CoA biosynthesis, pyrimidine metabolism, and steroid hormone biosynthesis pathway. The decrease in these metabolites was closely associated with increased harmful bacteria and reduced commensal bacteria. The content of short-chain fatty acids (SCFAs) such as acetic acid and propionic acid in the feces of BRV and BCoV-infected calves with diarrhea was lower than that of healthy calves, which was associated with the depletion of SCFAs-producing bacteria such as Parabacteroides, Fournierella, and Collinsella. The present study showed that BRV and BCoV infections changed the composition of the calf fecal microbiota and were associated with changes in fecal metabolites. This study lays the foundation for further revealing the roles of intestinal microbiota in neonatal calf diarrhea associated with BRV and BCoV infection.

TSG-6 alleviates cerebral ischemia/reperfusion injury and blood-brain barrier disruption by suppressing ER stress-mediated inflammation.

Tumor necrosis factor-stimulated gene-6 (TSG-6) exhibits promising neuroprotective activity, but how it influences cerebral ischemia/reperfusion (CIR) injury remains to be established. Here, the impact of TSG-6 on the CIR-induced disturbance in the blood-brain barrier (BBB) and associated neurological degeneration was assessed, and the related molecular processes were explored. In this study, TSG-6 markedly reduced CIR-mediated increases in neurological deficit scores, decreased infarct volume, and protected against the apoptotic death of neurons in MCAO/R model rats. Similarly, TSG-6 pretreatment protected cultured neurons against OGD/R-associated neuronal death. TSG-6 also restored BBB integrity, suppressing PERK-eIF2α and IRE1α-TRAF2 pathway activation in CIR model systems, thereby inhibiting NF-κB, TNF-α, IL-1ß, and IL-6. The further use of specific inhibitors of ER stress, 4-phenyl butyric acid (4-PBA), PERK (GSK2656157), and IRE1α (STF083010) demonstrated the ability of ER stress to drive inflammatory activity in the context of CIR injury i the PERK-eIF2α-NF-κB and IRE1α-TRAF2-NF-κB pathways. Consistently, the activation of ER stress using tunicamycin resulted in reversing the beneficial effects of TSG-6 on CIR-associated BBB disruption and neurological damage in vitro and in vivo. Treatment with TSG-6 can protect against CIR injury via the inhibition of ER stress-related inflammatory activity induced through the PERK-eIF2α-NF-κB and IRE1α-TRAF2-NF-κB pathways.

Quantitative phase imaging based on polarization encoding.

Most optical characterization methods rely on measuring the complex optical fields emerging from the interaction between light and material systems. Nevertheless, inherent scattering and absorption cause ambiguities in both interferometric and noninterferometric attempts to measure phase. Here we demonstrate that the complete information about a probe optical field can be encoded into the states of polarization, and develop a topography measurement method by blindly varying the ambient refractive index surrounding the sample in a wedged cuvette, which is capable of simultaneously measuring the thickness and the ambient refractive index of the sample in real time, as well as extending the measurement range of the sample thickness. With the method, we have successfully measured the topography of a 136.7 µm thick coverslip by blindly changing the ambient refractive index by 0.001246, resulting in the thickest sample characterization ever achieved by quantitative phase imaging, to the best of our knowledge. An efficient and complete characterization of optical fields is critical for any high-resolution imaging approach and the technique demonstrated here should prove attractive for applications ranging from microscopy to remote sensing. Thanks to the high precision and fast response speed, this method may pave a new way for measuring the topography of the thick samples, such as biological tissues.

[Effects of electroacupuncture on ethology, microglia activation and P2X7 receptor expression in periaqueductal gray in rats with migraine].

OBJECTIVE: To observe the effects of electroacupuncture(EA) at "Fengchi"(GB20) on the ethology, microglia activation and P2X7 receptor(P2X7R) expression in the periaqueductal gray(PAG) in recurrent migraine rat model, so as to explore the underlying mechanism of EA reducing central sensitization of migraine. METHODS: Thirty-six male SD rats were randomly divided into control, model and EA groups, with 12 rats in each group. Recurrent migraine model was induced using repea-ted dural electrical stimulation once another day(the 1st, 3rd, 5th, 7th and 9th days), for a total of 5 times; rats in the EA group received EA treatment(2 Hz/15 Hz, 0.8-1 mA) at GB20 after dural electrical stimulation, for 10 min every time, once a day for 9 days; rats in the control group only received electrode placement. The facial and hindpaw mechanical withdrawal threshold was detected by using an electronic von-Frey on the 0th(baseline), 2nd, 4th, 6th, and 8th days. Microglia activation in the PAG was evaluated by using immunofluorescence staining to detect the number of ionized calcium binding adaptor molecule-1(Iba-1)-labeled microglia. Expression levels of microglia marker Iba-1, inflammatory factor interleukin(IL)-1ß and P2X7R were detected by Western blot. RESULTS: Compared with the control group, the facial and hindpaw mechanical withdrawal threshold of rats were significantly reduced on the 2nd, 4th, 6th, and 8th days(P<0.01，P<0.001); the microglia in the PAG area were significantly activated, with the number of Iba-1-positive microglia, and the expression levels of Iba-1, IL-1ß and P2X7R proteins significant increased(P<0.001, P<0.05) in the model group. Compared with the model group, the facial and hindpaw mechanical withdrawal threshold of rats were significantly increased on the 4th, 6th, and 8th days(P<0.05，P<0.001，P<0.01), and the above indicators were significantly reversed (P<0.05) in the EA group. CONCLUSION: EA at GB20 can significantly improve facial and hindpaw mechanical withdrawal threshold of migraine rats, and its possible mechanism may be related to inhibiting microglia activation mediated by P2X7R in the PAG.

Effect of Electroacupuncture at Fengchi on Facial Allodynia, Microglial Activation, and Microglia-Neuron Interaction in a Rat Model of Migraine.

The purpose of the work was to investigate whether electroacupuncture (EA) could ameliorate migraine central sensitization by modulating microglial activation and the subsequent release of inflammatory cytokines in the trigeminal nucleus caudalis (TNC) in a rat model. Establishment of a rat model of recurrent migraine was achieved through repeated dural electrical stimulation (DES). After nine sessions of acupuncture treatment at Fengchi (GB20), facial mechanical thresholds were measured by electronic von Frey measurements. Microglial activation and cytokine receptors of TNC were evaluated by immunofluorescence staining. The expression of microglial biological marker Ibal-1, proinflammatory cytokines, and cytokine receptors in the TNC were evaluated by Western blot and/or real-time polymerase chain reaction. In addition, the effects of inhibition of microglial activation on facial thresholds and neuronal activation (i.e., expression of c-Fos in the TNC) induced by DES were observed. After consecutive EA-GB20 treatments, the facial withdrawal threshold was significantly higher than in the model group at different time points (p < 0.05). The hyperreactivity of microglia induced by DES was significantly inhibited, and the expressions of Ibal-1, interleukin-1ß, tumor necrosis factor-α, and their receptors in the TNC were also significantly decreased (p < 0.05). Inhibition of microglia by minocycline demonstrated an acupuncture-like role, which was manifested by ameliorated mechanical hyperalgesia and decreased neuronal expression of c-Fos, Iba-1, and inflammatory factors. EA at GB20 could ameliorate migraine facial allodynia by inhibiting microglial activation and the subsequent release of inflammatory cytokines and their receptors in the TNC.

Polarization-encoded field measurement in subwavelength scattering.

We demonstrate that polarization encoding provides a convenient way to realize a robust common-path interferometer for measuring both the phase and the amplitude of scattered optical fields. Moreover, for a given detector array, the design allows maximizing the interferometric visibility and, therefore, permits reaching the sensitivity limit for the field measurement. The approach is of particular interest for inefficient scattering scenarios such as subwavelength scattering.

Determining topological charge based on an improved Fizeau interferometer.

We propose a new method to determine topological charge by using an improved Fizeau interferometer. This interferometer is very easy to realize, as well as interference fringes are very distinct. Phases of vortex, Hermite-Gaussian, and elliptical vortex beams are experimentally verified using this method. It provides a convenient way to determine the sign and magnitude of topological charge. This method may have some potential applications in space optical communication.

Efficient and compact orthogonally polarized dual-wavelength Nd:YVO4 laser at 1342 and 1345 nm.

Based on a free-running diode-end-pumped a-cut Nd:YVO4 laser with output power of 3.61 W at a single wavelength of π-polarized 1342 nm, we further obtain a 1.82 W σ-polarized 1345 nm laser with a slope efficiency of about 22.3% by introducing an intracavity etalon, for the first time to the best of our knowledge. In addition, a simultaneous dual-wavelength orthogonally polarized laser at π-polarized 1342 nm and σ-polarized 1345 nm can also be achieved with a maximum output power of 1.35 W. The dual-wavelength laser provides a potential laser source for terahertz wave generation.

Diode-pumped continuous-wave dual-wavelength c-cut Pr³âº:LiYF4 laser at 696 and 719 nm.

A continuous-wave, InGaN-LD-pumped dual-wavelength laser is demonstrated with simultaneous emission at 696 (3P03F(→)3) and 719 nm (3P03F(→)4) using a c-cut Pr(3+):LiYF4, for the first time to our knowledge. Maximum output power of 102 mW at these two wavelengths is achieved with slope efficiency of about 15.6% with respect to the absorbed pump power. The beam propagation factors in x and y directions are measured to be 1.50 and 1.32, respectively.

Measuring the intensity fluctuation of partially coherent radially polarized beams in atmospheric turbulence.

The scintillation index of a Gaussian beam and radially polarized beams in turbulent atmosphere is experimentally investigated. The scintillation index of a Gaussian beam and a completely coherent radially polarized beam increases with increasing propagation distance from 0 to 400m. The influence of the coherence of partially coherent radially polarized beam on the scintillation is studied. The result shows that the scintillation index of a partially coherent radially polarized beam can be smaller than that of a completely coherent beam.

Experimental generation of nonuniformly correlated partially coherent light beams.

We report the experimental realization of nonuniformly correlated partially coherent light (NUCPCL) beams by passing laser beams through a phase-only spatial light modulator. The characteristics of NUCPCL beams whose coherence is of Gaussian distribution as well as inverse Gaussian distribution are studied theoretically and experimentally. It is shown that the experimental observations are in agreement with our theoretical analysis. NUCPCL beams may have some applications in optical manipulation.