Physiological and transcription analyses reveal regulatory pathways of 6-benzylaminopurine delaying leaf senescence and maintaining quality in postharvest Chinese flowering cabbage.

The regulatory role of cytokinins (CTKs) in leaf senescence has been documented in different species, including Chinese flowering cabbage. However, its physiological and molecular basis relatively remains unknown. In this study, exogenous application of a CTK analogue 6-benzylaminopurine (6-BA) significantly retarded leaf senescence of Chinese flowering cabbage, with less chlorophyll degradation and lower accumulation of reactive oxygen species (ROS) and malondialdehyde compared with the control group. Meanwhile, higher levels of soluble sugars and proteins, flavonoids, cellulose, amino acids, total phenols, procanthocyanins, and vitamin C were retained in 6-BA-treated leaves. 6-BA treatment also prevented the decline in endogenous CTK content and the increase in ethylene, abscisic acid, and jasmonic acid contents. Moreover, the comparative transcriptome analysis revealed that a total of 21,895 differently expressed genes (DEGs) were identified from four comparisons of 6-BA treatment versus the control during senescence. Further analysis showed that most of the identified DEGs were enriched in ROS, respiratory metabolism, and phytohormone pathways, and a total of 50 classes of transcription factors that were possibly involved in modulating these DEGs were obtained. The transcriptional levels of 18 DEGs were verified by Quantitative real-time PCR (qRT-PCR), which confirmed the accuracy of the transcriptomic data. Overall, these findings and data provide a comprehensive view of physiological and molecular events concerning with the CTK-mediated leaf senescence and -maintained quality in economical leafy vegetables.

In vivo Neuroregeneration to Treat Ischemic Stroke Through NeuroD1 AAV-Based Gene Therapy in Adult Non-human Primates.

Stroke may cause severe death and disability but many clinical trials have failed in the past, partially because the lack of an effective method to regenerate new neurons after stroke. In this study, we report an in vivo neural regeneration approach through AAV NeuroD1-based gene therapy to repair damaged brains after ischemic stroke in adult non-human primates (NHPs). We demonstrate that ectopic expression of a neural transcription factor NeuroD1 in the reactive astrocytes after monkey cortical stroke can convert 90% of the infected astrocytes into neurons. Interestingly, astrocytes are not depleted in the NeuroD1-converted areas, consistent with the proliferative capability of astrocytes. Following ischemic stroke in monkey cortex, the NeuroD1-mediated astrocyte-to-neuron (AtN) conversion significantly increased local neuronal density, reduced microglia and macrophage, and surprisingly protected parvalbumin interneurons in the converted areas. Furthermore, the NeuroD1 gene therapy showed a broad time window in AtN conversion, from 10 to 30 days following ischemic stroke. The cortical astrocyte-converted neurons showed Tbr1+ cortical neuron identity, similar to our earlier findings in rodent animal models. Unexpectedly, NeuroD1 expression in converted neurons showed a significant decrease after 6 months of viral infection, indicating a downregulation of NeuroD1 after neuronal maturation in adult NHPs. These results suggest that in vivo cell conversion through NeuroD1-based gene therapy may be an effective approach to regenerate new neurons for tissue repair in adult primate brains.

Synchrony makes neurons fire in sequence, and stimulus properties determine who is ahead.

The synchronized activity of cortical neurons often features spike delays of several milliseconds. Usually, these delays are considered too small to play a role in cortical computations. Here, we use simultaneous recordings of spiking activity from up to 12 neurons to show that, in the cat visual cortex, the pairwise delays between neurons form a preferred order of spiking, called firing sequence. This sequence spans up to ∼ 15 ms and is referenced not to external events but to the internal cortical activity (e.g., beta/gamma oscillations). Most importantly, the preferred sequence of firing changed consistently as a function of stimulus properties. During beta/gamma oscillations, the reliability of firing sequences increased and approached that of firing rates. This suggests that, in the visual system, short-lived spatiotemporal patterns of spiking defined by consistent delays in synchronized activity occur with sufficient reliability to complement firing rates as a neuronal code.

[Feature extraction and pupil size detection of pupillary light reflex in opiate addicts].

An effective algorithm for detecting pupil size based on image processing was established. Three features reflecting differences between opiate addicts and normal subjects in pupillary light reflex were extracted by applying this algorithm, including absolute amplitude of contraction (AAC), relative amplitude of contraction (RAC) and slope of contraction velocity (SCV). Effects of addiction, sex, myopia, aging, sleep deprivation on the three features were studied. None of three features was found significant differences between sexes, myopia, sleep deprived and normal subjects. Only RAC increased significantly in aging subjects in comparison to opiate addicts, The features of pupillary light reflex in opiate addicts decreased significantly not only comparing with normal subjects, but the subjects with potential facts that may alter their pattern of pupil light reflex as well. Our study provided basic data for future establishment of a rapid, non-contact method in distinguishing opiate addicts from other subjects based on pupillary light reflex.

[Effects of morphine on pupillary light reflex in monkeys].

The pupil size of both human and other animals can be affected by light. Many kinds of psychiatrical and psychological disorders, such as drug abuse, associate with abnormal properties of pupillary light reflex. Thus, the properties of pupillary light reflex could serve as an indicator for drug abuse detection. However, the effect of drug abuse on pupillary light reflex is till unclear. To assess the effects of addictive drugs on pupillary light reflex quantificationally, in the present study, we examined the effects of morphine on pupil diameter and pupillary light reflex in rhesus monkeys. By measuring the pupil diameter at different timing points before and after the administration of morphine, we found that morphine administration reduced the diameter of pupil and decreased the constriction rate. Our present results provide an experimental support for applying the properties of pupillary light reflex as a reference in addicts' detection.

Synchronization dynamics in response to plaid stimuli in monkey V1.

Gamma synchronization has generally been associated with grouping processes in the visual system. Here, we examine in monkey V1 whether gamma oscillations play a functional role in segmenting surfaces of plaid stimuli. Local field potentials (LFPs) and spiking activity were recorded simultaneously from multiple sites in the opercular and calcarine regions while the monkeys were presented with sequences of single and superimposed components of plaid stimuli. In accord with the previous studies, responses to the single components (gratings) exhibited strong and sustained gamma-band oscillations (30-65 Hz). The superposition of the second component, however, led to profound changes in the temporal structure of the responses, characterized by a drastic reduction of gamma oscillations in the spiking activity and systematic shifts to higher frequencies in the LFP ( approximately 10% increase). Comparisons between cerebral hemispheres and across monkeys revealed robust subject-specific spectral signatures. A possible interpretation of our results may be that single gratings induce strong cooperative interactions among populations of cells that share similar response properties, whereas plaids lead to competition. Overall, our results suggest that the functional architecture of the cortex is a major determinant of the neuronal synchronization dynamics in V1.

[Methods for single unit recording in behavioring morphine craving rat].

In this paper, one method was introduced, which was a combination of the cue-related morphine addiction model and a technique for obtaining chronic extracellular recordings of single unit in freely moving rats. With the combination and improvement of this technique, we have successfully applied this new method to study the neuronal activity of the hippocampus CA1 region in morphine withdrawal rats. In all, we found some more accurate and objective cellular characteristics of hippocampal neurons, and considered these characteristics as one of electrophysiological indexes of morphine addiction rats.

[Analysis on the characteristics of histological location of bursin in immune organ of chicken and duck].

The distribution of Bursin in major immune organs such as bursa of Fabricius (BF), thymus (Th), Harderian gland(HG) and spleen(Sp) was investigated and compared in both chicken and duck by immuno-histochemical staining method with anti-Bursin monoclonal antibody (McAb)2F9-4. Its distributions in bone marrow(BM) and embryonic organs including BF, Th, BM, HG in chicken were also determined in addition to locating it in germinal center(GC) of Sp and lymphatic nodules of lymphonode in duck. The results showed clearly that Bursin was generally located in immune organs in both chicken and duck. However, its distributive regularity in chick was different from that appeared in duck. In addition, the biological significance on Bursin distribution in immune organs was discussed.