Prospective representations in rat orbitofrontal ensembles.

The orbitofrontal cortex (OFC) has been proposed to encode expected outcomes, which is thought to be important for outcome-directed behavior. However, such neural encoding can also often be explained by the recall of information about the recent past. To dissociate the retrospective and prospective aspects of encoding in the OFC, we designed a nonspatial, continuous, alternating odor-sequence task that mimicked a continuous T-maze. The task consisted of two alternating sequences of four odor-guided trials (2 sequences × 4 positions). In each trial, rats were asked to make a "go" or "no-go" action based on a fixed odor-reward contingency. Odors at both the first and last positions were distinct across the two sequences, such that they resembled unique paths in the past and future, respectively; odors at positions in between were the same and thus resembled a common path. We trained classifiers using neural activity to distinguish between either sequences or positions and asked whether the neural activity patterns in the common path were more like the ones in the past or the future. We found a proximal prospective code for sequence information as well as a distal perspective code for positional information, the latter of which was closely associated with rats' ability to predict future outcomes. This study demonstrates a behaviorally relevant predictive code in rat OFC. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Evolving schema representations in orbitofrontal ensembles during learning.

How do we learn about what to learn about? Specifically, how do the neural elements in our brain generalize what has been learned in one situation to recognize the common structure of-and speed learning in-other, similar situations? We know this happens because we become better at solving new problems-learning and deploying schemas1-5-through experience. However, we have little insight into this process. Here we show that using prior knowledge to facilitate learning is accompanied by the evolution of a neural schema in the orbitofrontal cortex. Single units were recorded from rats deploying a schema to learn a succession of odour-sequence problems. With learning, orbitofrontal cortex ensembles converged onto a low-dimensional neural code across both problems and subjects; this neural code represented the common structure of the problems and its evolution accelerated across their learning. These results demonstrate the formation and use of a schema in a prefrontal brain region to support a complex cognitive operation. Our results not only reveal a role for the orbitofrontal cortex in learning but also have implications for using ensemble analyses to tap into complex cognitive functions.

Prd1 associates with the clathrin adaptor α-Adaptin and the kinesin-3 Imac/Unc-104 to govern dendrite pruning in Drosophila.

Refinement of the nervous system depends on selective removal of excessive axons/dendrites, a process known as pruning. Drosophila ddaC sensory neurons prune their larval dendrites via endo-lysosomal degradation of the L1-type cell adhesion molecule (L1-CAM), Neuroglian (Nrg). Here, we have identified a novel gene, pruning defect 1 (prd1), which governs dendrite pruning of ddaC neurons. We show that Prd1 colocalizes with the clathrin adaptor protein α-Adaptin (α-Ada) and the kinesin-3 immaculate connections (Imac)/Uncoordinated-104 (Unc-104) in dendrites. Moreover, Prd1 physically associates with α-Ada and Imac, which are both critical for dendrite pruning. Prd1, α-Ada, and Imac promote dendrite pruning via the regulation of endo-lysosomal degradation of Nrg. Importantly, genetic interactions among prd1, α-adaptin, and imac indicate that they act in the same pathway to promote dendrite pruning. Our findings indicate that Prd1, α-Ada, and Imac act together to regulate discrete distribution of α-Ada/clathrin puncta, facilitate endo-lysosomal degradation, and thereby promote dendrite pruning in sensory neurons.

Preparation of PVA/amino multi-walled carbon nanotubes nanocomposite microspheres for endotoxin adsorption.

A novel polyvinyl alcohol-amino multi-walled carbon nanotube (PVA-AMWCNT) nanocomposite microsphere was prepared successfully for the first time and used for endotoxin removal. The resulting AMWCNT modified PVA microsphere was characterized by SEM, Raman spectrum and fluorescence image, which indicated AMWCNT was dispersed into the macropores of PVA microsphere uniformly. The PVA-AMWCNT microspheres showed better adsorption capability and faster adsorption equilibrium for endotoxin in aqueous solution when compared to the PVA microsphere with polymyxin B (PMB) as ligand. More noteworthy, the PVA based microspheres had little nonspecific adsorption in simulated serum. Therefore, PVA-AMWCNT nanocomposite microsphere with an excellent haemocompatibility has a great potential application in clinical blood purification.

Preparation of chitosan/amino multiwalled carbon nanotubes nanocomposite beads for bilirubin adsorption in hemoperfusion.

Chitosan-carbon nanotube composite beads combines the advantages of chitosan in forming a stable biocompatible framework and carbon nanotube that provide nanometer effects (high strength and high specific surface area etc.). In this study, chitosan/amino multiwalled carbon nanotubes (CS/AMWCNT) composite beads was prepared by phase-inversion method, in which CS and AMWCNT was crosslinked by ethylene glycol diglycidyl ether (EGDE). The CS/AMWCNT nanocomposite beads produced has been characterized by BET, SEM, TGA, and Raman spectroscopy which exhibited enhanced thermal stability due to the incorporation of AMWCNT. Mechanical test results showed that mechanical strength of the CS/AMWCNT composite beads was significantly enhanced when comparing to unmodified chitosan beads, the breakage percentage decreased from 34.1% to 0.67%. The adsorption capacity for bilirubin was measured in PBS and BSA solutions, and the CS/AMWCNT composite beads with 5 wt% AMWCNT showed much higher adsorption capacity (12.7 mg/g in PBS and 7.6 mg/g in BSA) to bilirubin than chitosan beads (8.5 mg/g in PBS and 4.2 mg/g in BSA). Our nanocomposite beads with excellent hemocompatibility has a high potential application in blood purification as an efficient adsorbent for bilirubin. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 96-103, 2018.

Preparation of nano-CaCO3/polystyrene nanocomposite beads for efficient bilirubin removal.

A novel nano-CaCO3/polystyrene nanocomposite adsorbent (NPS-8) was synthesized for efficient bilirubin removal from human plasma. A comparison with the polystyrene adsorbent (PS-8), which was without the incorporation of nano-CaCO3, revealed that NPS-8 had superior bilirubin adsorption capacity and mechanical strength. The resulting nano-CaCO3 reinforced PS-8 (NPS-8) was tested by transmission electron microscopy (TEM), scanning electron microscopy (SEM), mechanical strength test, and bilirubin adsorption assays. The adsorption results indicated that NPS-8 displayed better adsorption capacity for bilirubin (91%) than that of PS-8 (75.88%). The mechanical strength of NPS-8 was significantly greater than that of PS-8. In addition, both PS-8 and NPS-8 possessed good blood compatibility properties (a negligible hemolytic activity and platelet adhesion). Therefore, a conclusion could be drawn that NPS-8 has a high potential as an efficient bilirubin adsorbent for blood purification in clinical practice. At the same time, the success of organic-inorganic nanocomposite adsorbents might provide a new insight into the improvement of adsorbents in hemoperfusion.

High performance of a unique mesoporous polystyrene-based adsorbent for blood purification.

A multi-functional polystyrene based adsorbent (NKU-9) with a unique mesoporous and a high surface area was prepared by suspension polymerization for removal of therapeutic toxins in blood purification. The adsorbent produced had an almost equal amount of mesopore distribution in the range from 2 to 50 nm. The adsorption of serum toxins with different molecular weights were examined by in vitro adsorption assays and compared with some clinical currently used adsorbents such as HA-330, Cytosorb and BL-300 which are produced by China, America and Japan, respectively. Test results indicated that the adsorption rate for pentobarbital by NKU-9 was 81.24% which is nearly as high as HA-330 (81.44%). The latter adsorbent is currently used for acute detoxification treatment in China. To reach adsorption equilibrium, NKU-9 was faster than HA-330, which implies short treatment time. For the removal of middle molecular toxins such as ß2-microglobulin (98.88%), NKU-9 performed better adsorptive selectivity than Cytosorb (92.80%). In addition, NKU-9 showed high performance for the removal of albumin-bound toxins (e.g., bilirubin), and its adsorption rate for total bilirubin (80.79%) in plasma was 8.4% higher than that of anion exchange resin BL-300 which is currently used to eliminate bilirubin in clinic. Therefore, our results indicate that the newly developed adsorbent with a wide distribution and almost equal amount of mesopores is a multifunctional adsorbent for high efficient removal of serum toxins with different molecular weights which might be an excellent blood purification adsorbent especially to treat diseases that conventional medical methods are low or not efficient.

Non-ionic macroporous polystyrene adsorbents for removal of serum toxins in liver failure by hemoperfusion.

Strong base anion exchange resin (e.g., BL-300) is currently used to eliminate bilirubin from blood in clinical hemoperfusion. However, there is a potential weakness of the resin to remove heparin and activation of coagulation. To overcome this weakness, we prepared a novel non-ionic macroporous polystyrene adsorbent (SZ-9) with rich mesopores and high surface area by suspension polymerization. Test results indicated that SZ-9 performed better adsorption capacity for bilirubin than BL-300. In addition, better blood compatibility was observed during whole blood hemoperfusion. Therefore, adsorbent SZ-9 might be an efficient alternative to anion exchange resin for the removal of bilirubin in hemoperfusion.

Arl2- and Msps-dependent microtubule growth governs asymmetric division.

Asymmetric division of neural stem cells is a fundamental strategy to balance their self-renewal and differentiation. It is long thought that microtubules are not essential for cell polarity in asymmetrically dividing Drosophila melanogaster neuroblasts (NBs; neural stem cells). Here, we show that Drosophila ADP ribosylation factor like-2 (Arl2) and Msps, a known microtubule-binding protein, control cell polarity and spindle orientation of NBs. Upon arl2 RNA intereference, Arl2-GDP expression, or arl2 deletions, microtubule abnormalities and asymmetric division defects were observed. Conversely, overactivation of Arl2 leads to microtubule overgrowth and depletion of NBs. Arl2 regulates microtubule growth and asymmetric division through localizing Msps to the centrosomes in NBs. Moreover, Arl2 regulates dynein function and in turn centrosomal localization of D-TACC and Msps. Arl2 physically associates with tubulin cofactors C, D, and E. Arl2 functions together with tubulin-binding cofactor D to control microtubule growth, Msps localization, and NB self-renewal. Therefore, Arl2- and Msps-dependent microtubule growth is a new paradigm regulating asymmetric division of neural stem cells.

[Establishment of molecular markers linked to sex in Schisandra sphenanthera].

OBJECTIVE: To establish the gender-related RAPD markers in Schisandra sphenanthera. METHODS: The genomic DNA was extracted from the young leaves of male and female Schisandra sphenanthera by modified CTAB method. The gender differences in the genome were studied by RAPD which was optimized by the single factor and orthogonal experiments. RESULTS: 25 microL total volume included Mg2+ of 2.5 mmol/L, dNTPs of 0.08 mmol/L, primer of 0.6 micromol/L, Taq enzyme 1.5 U, DNA template 60 ng, annealing temperature 41.3 degrees C, 35 cycles. In 400 random primers, only a male specific band 541 bp was generated by S353. CONCLUSION: The marker can be used as the basis of gender identification.