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Chao Qin

Publications and source records attributed to Chao Qin.

At least 19 recordsLinked to original sources
PubMed2026

DAZL-targeted inducible kill switches enable efficient ablation of chicken primordial germ cells.

Competition from endogenous primordial germ cells (PGCs) in recipient embryos limits the generation of fully donor-derived offspring in avian surrogate-host systems. An inducible and germline-restricted ablation strategy is therefore needed to create sterile recipients without compromising somatic development. Using CRISPR/Cas9-mediated homology-directed repair, we inserted three inducible suicide-gene cassettes (iCaspase9, RapaCasp9, and CD) into the endogenous DAZL locus of chicken PGCs. All knock-in lines showed stable reporter expression and retained typical PGC morphology. Comparative functional analyses identified iCaspase9 activated by AP20187 as the most sensitive and specific ablation system, achieving near-complete killing at nanomolar concentrations without detectable toxicity in control cells. RapaCasp9 induced with rapamycin also ablated engineered PGCs efficiently, but rapamycin caused marked non-specific growth inhibition in control cells. Replacing rapamycin with the synthetic A/C heterodimerizer AP21967 largely eliminated this off-target toxicity while preserving rapid and robust killing. By contrast, yeast-derived CD variants did not substantially improve 5-fluorocytosine sensitivity in chicken PGCs. DAZL-restricted iCaspase9/AP20187 and the optimized RapaCasp9/AP21967 system provide efficient inducible kill switches for chicken PGCs in vitro. These platforms establish a practical genetic toolkit for generating sterile surrogate hosts to support avian genome editing, germline replacement, and Sire Dam Surrogate breeding.

CRISPR/Cas9↗
PubMed2024

Micro-interfacial behavior of antibiotic-resistant bacteria and antibiotic resistance genes in the soil environment: A review.

Overutilization and misuse of antibiotics in recent decades markedly intensified the rapid proliferation and diffusion of antibiotic resistance genes (ARGs) within the environment, thereby elevating ARGs to the status of a global public health crisis. Recognizing that soil acts as a critical reservoir for ARGs, environmental researchers have made great progress in exploring the sources, distribution, and spread of ARGs in soil. However, the microscopic state and micro-interfacial behavior of ARGs in soil remains inadequately understood. In this study, we reviewed the micro-interfacial behaviors of antibiotic-resistant bacteria (ARB) in soil and porous media, predominantly including migration-deposition, adsorption, and biofilm formation. Meanwhile, adsorption, proliferation, and degradation were identified as the primary micro-interfacial behaviors of ARGs in the soil, with component of soil serving as significant determinant. Our work contributes to the further comprehension of the microstates and processes of ARB and ARGs in the soil environments and offers a theoretical foundation for managing and mitigating the risks associated with ARG contamination.

Soil Microbiology↗
PubMed2006

Transient receptor potential vanilloid receptor-1 does not contribute to slowly adapting airway receptor activation by inhaled ammonia.

Inhalation of ammonia influences the activity of slowly adapting airway receptors (SARs), but the mechanism(s) is uncertain. Release of inflammatory mediators by transient receptor potential vanilloid receptor-1 (TRPV1) containing nerve endings could affect SAR response to ammonia. We examined how sensitization and subsequent desensitization of the TRPV1 by resiniferatoxin (RTX), affected the responses of SARs to inhaled ammonia. In pentobarbital-anesthetized, paralyzed and artificially ventilated rats, the left cervical vagus nerve was exposed, sectioned rostrally, and desheathed. Single fibers of SARs were identified and recorded. Two milliliters of ammonia vapor (from a 30% NH(4)OH solution) was inhaled over 20 s and responses to ammonia were measured. RTX was injected intravenously at 2 microg/Kg. Twenty minutes later, ammonia inhalation was repeated. Isoproterenol (ISO, 100 microg/kg, i.v.) was used in another set of experiments to block possible ammonia-induced bronchoconstriction. Ammonia increased tonic activity of SARs (n=10, P<0.0001), with complex changes in ventilator-related activity. SAR firing rate began to increase 2.3+/-0.2 min after RTX and returned to control levels at 13.6+/-1.4 min (n=10). By 20 min after RTX cardiovascular responses to ammonia were abolished, but effects on SAR activity were essentially unchanged. ISO did not modify the response of SARs to ammonia (n=8). These data suggest that responses of SARs to ammonia in rats do not depend on release of mediators by nerve endings containing TRPV1 and are not secondary to bronchoconstriction. However, when TRPV1 containing nerve endings were initially activated by RTX, the release of mediators may have affected SAR discharges.

Action Potentials↗
PubMed2006

Modulatory effects and afferent pathways of gastric electrical stimulation on rat thoracic spinal neurons receiving input from the stomach.

Gastric electrical stimulation (GES) has been suggested as a potential therapy for patients with obesity or gastric motility disorders. The aim of this study was to investigate the spinal mechanism of GES effects on gastric functions. Extracellular potentials of single spinal (T9-T10) neurons were recorded in pentobarbital anesthetized, paralyzed, ventilated male rats (n=19). Gastric distension (GD) was produced by air inflation of a balloon. One pair of platinum electrodes (1.0-1.5cm apart) was sutured onto the serosal surface of the lesser curvature of the stomach. GES with four sets of parameters was applied for 1min: GES-A (6mA, 0.3ms, 40Hz, 2s on, 3s off), GES-B (6mA, 0.3ms, 14Hz, 0.1s on, 5s off), GES-C (6mA, 3ms, 40Hz, 2s on, 3s off), GES-D (6mA, 200ms, 12pulses/min). 62/158 (39%) spinal neurons responded to GD (20, 40, 60mmHg, 20s. Most GD-responsive neurons (n=43) had excitatory responses; the remainder had inhibitory (n=12) or biphasic responses (n=7). GES-A, -B, -C and -D affected activity of 12/33 (36%), 4/31 (13%), 22/29 (76%) and 13/30 (43%) GD-responsive neurons, respectively. Bilateral cervical vagotomy did not significantly alter mean excitatory neuronal responses to GD (n=5) or GES (n=6). Resiniferatoxin (2.0microg/kg, i.v.), an ultrapotent agonist of vanilloid receptor-1, abolished excitatory responses to GD and GES in 4/4 neurons recorded in vagotomized rats. The results suggested that GES mainly had an excitatory effect on T9-T10 spinal neurons with gastric inputs; neuronal responses to GES were strengthened with stimulation at an increased pulse width and/or number of pulses. The modulatory effect of GES involved thoracic spinal (sympathetic) afferent fibers containing vanilloid receptor-1.

Action Potentials↗
PubMed2006

Afferent pathway and neuromodulation of superficial and deeper thoracic spinal neurons receiving noxious pulmonary inputs in rats.

The occurrence of vagally mediated afferent signaling by lung irritants is well known. However, spinal visceral afferent pathways also might be relevant to pulmonary irritation. In the present study, responses and modulation of superficial and deep T3 spinal neurons were examined using inhaled ammonia, and the peripheral afferent fibers were also characterized in part. Extracellular potentials of single thoracic (T3) spinal neurons were recorded in pentobarbital anesthetized, paralyzed, and ventilated male rats. Ammonia vapor (0.5, 1.0, 2.0 ml) was injected into the inspiratory line of the ventilator for 20 s. Inhaled ammonia (IA, 1.0 ml) excited 5/6 neurons and inhibited one spinal neuron recorded in superficial laminae, whereas deeper neurons responded with excitatory (E, n = 20), inhibitory (I, n = 4) or biphasic patterns (6 E-I, 3 I-E). Electrical and chemical stimulation of C1-C2 spinal neurons primarily suppressed T3 neuronal responses to IA. Resiniferatoxin (2 microg/kg, i.v.), which desensitizes afferent fibers containing transient receptor potential vanilloid receptor-1 (TRPV-1), abolished excitatory responses of 8/8 neurons to IA. Bilateral cervical vagotomy did not affect IA responses in 5 superficial neurons while 7 deeper neurons showed variable responses. 82% (32/39) of the spinal neurons responding to IA also received convergent noxious inputs from somatic fields in the chest and back areas. These results suggested that superficial and deeper spinal neuronal activation by inhaled ammonia mainly depended upon pulmonary sympathetic afferent fibers expressing TRPV-1. Additionally, C1-C2 spinal neurons, supraspinal sites and vagal afferents modulated the thoracic spinal neuronal responses to lower airway irritation.

Action Potentials↗
PubMed2006

Responses of thoracic spinal neurons to activation and desensitization of cardiac TRPV1-containing afferents in rats.

The purpose of this study was to examine how upper thoracic spinal neurons responded to activation and desensitization of cardiac transient receptor potential vanilloid-1 (TRPV1)-containing afferent fibers. Extracellular potentials of single T3 spinal neurons were recorded in pentobarbital-anesthetized, paralyzed, and ventilated male rats. To activate cardiac nociceptive receptors, a catheter was placed in the pericardial sac to administer various chemicals: bradykinin (BK; 10 microg/ml, 0.2 ml), capsaicin (CAP, 10 microg/ml, 0.2 ml), or a mixture of algesic chemicals (AC; 0.2 ml) containing adenosine 10(-3) M, BK, serotonin, histamine, and PGE(2), 10(-5) M for each. Spinal neurons that responded to intrapericardial BK and/or CAP were used in this study. Results showed that 81% (35/43) of the neurons had excitatory responses to both intrapericardial BK and CAP, and the remainder responded to either BK or CAP. Intrapericardial resiniferatoxin (RTX) (0.2 microg/ml, 0.2 ml, 1 min), which desensitizes TRPV1-containing nerve endings, abolished excitatory responses to both BK (n = 8) and CAP (n = 7), and to AC (n = 5) but not to somatic stimuli. Intrapericardial capsazepine (1 mg/ml, 0.2 ml, 3 min), a specific antagonist of TRPV1, sharply attenuated excitatory responses to CAP in 5/5 neurons, but responses to BK in 5/5 neurons was maintained. Additionally, intrapericardial capsazepine had no significant effect on excitatory responses to AC in 3/3 neurons. These data indicated that intrapericardial BK-initiated spinal neuronal responses were linked to cardiac TRPV1-containing afferent fibers, but were not dependent on TRPV1. Intraspinal signaling for cardiac nociception was mediated through CAP-sensitive afferent fibers innervating the heart.

Adaptation, Physiological↗
PubMed2006

Sensory fibers containing vanilloid receptor-1 (VR-1) mediate spinal cord stimulation-induced vasodilation.

BACKGROUND AND AIMS: Spinal cord stimulation (SCS) is used to improve peripheral blood flow in selected populations of patients with ischemia of the extremities. Previous studies show that antidromic activation of sensory fibers is an important mechanism that contributes to SCS-induced vasodilation. However, the characteristics of sensory fibers involved in vasodilation are not fully known. This study investigated the contribution of vanilloid receptor type 1 (VR-1) containing fibers to SCS-induced vasodilation. METHODS: A unipolar ball electrode was placed on the left dorsal column at the lumbar 2-3 spinal cord segments (L2-L3) in sodium pentobarbital anesthetized, paralyzed and ventilated rats. Cutaneous blood flows from both ipsilateral (left) and contralateral (right) hind foot pads were recorded with laser Doppler flow perfusion monitors. SCS (50 Hz; 0.2 ms) was applied through the ball electrode at 30%, 60%, 90% and 300% of motor threshold (MT). Resiniferatoxin (RTX), an ultra potent analog of capsaicin and VR-1 receptor agonist, was used to suppress the activities of VR-1 containing sensory fibers. RESULTS: SCS at 30%, 60%, 90% and also at 300% of MT significantly increased cutaneous blood flow in the ipsilateral foot pad compared to that in the contralateral side. RTX (2 microg/kg, i.v.) significantly attenuated SCS-induced vasodilation of the ipsilateral side (P<0.05, n=7) compared with responses prior to RTX administration. A pledget of cotton soaked with RTX (2 microg/ml) placed on L2-L3 spinal cord significantly decreased SCS-induced vasodilation of the ipsilateral side at 30%, 60%, 90% and 300% of MT (P<0.05, n=7) compared with responses prior to RTX administration. Additionally, topical application of a pledget of cotton soaked with RTX (2 microg/ml) on the sciatic nerve at the middle level of the thigh or on the tibial nerve at the lower level of the lower hindlimb also decreased SCS-induced vasodilation (n=5). CONCLUSION: SCS-induced vasodilation is predominantly mediated via VR-1 containing sensory fibers.

Animals↗
PubMed2006

Synthesis, characterization, and crystal structures of two novel high-nuclear nickel-substituted dimeric polyoxometalates.

Two novel high-nuclear Ni-substituted polyoxometalates Na9K[Ni7(OH)4(H2O)(CO3)2(HCO3)(A-alpha-SiW9O34)(beta-SiW10O37)].5H3O.18H2O (1) and K6Na4[{Ni6(H2O)4(mu2-H2O)4(mu3-OH)2}(x-SiW9O34)2].17.5H2O (2) have been obtained by reaction of K(8)[gamma-SiW10O36] with NiCl2.2H2O in basic conditions. Compounds 1 and 2 all represent the first polyoxometalates substituted by seven and six Ni centers, respectively. Also, compound 1 exhibits a novel asymmetric dimeric structure, composed of [A-alpha-SiW9O34]10- and [beta-SiW10O37]10- units linked by a Ni7 cluster and three carbonates, which exhibit tri- and bidentate coordination modes in 1.

Journal Article↗
PubMed2006

Metal nuclearity modulated four-, six-, and eight-connected entangled frameworks based on mono-, bi-, and trimetallic cores as nodes.

To investigate the relationship between network connectivity and metal nuclearity, we designed and synthesized a series of three-dimensional (3D) entangled coordination frameworks based on different metal cores, namely [Zn(2)(bdc)(2)(L)(2)]2H(2)O (1), [Zn(bdc)(L)(0.5)] (2), [Zn(oba)(L)(0.5)] (3) and [Cd(3)(bdc)(3)(L)(2)(H(2)O)(2)] (4) by self-assembly of d(10) metal salts with the flexible long-chain ligand 1,4-bis(1,2,4-triazol-1-yl)butane (L), and with the rigid and nonrigid aromatic dicarboxylate ligands 1,4-benzenedicarboxylate (bdc) and 4,4'-oxybis(benzoate) (oba). Compound 1 exhibits a threefold interpenetrated diamondoid array typically based on a tetrahedral second building unit (SBU) at a single Zn center. Compound 2 adopts a threefold interpenetrated alpha-polonium-type network that is built from bimetallic cores as six-connected vertices. The structure of 3 also consists of dinuclear units; it comprises a novel (3,4)-connected threefold interpenetrated net with complex (4610)(46(2)10(3)) topology when single zinc centers act as four-connected nodes (or the alpha-Po topology if dinuclear units are considered as six-connected nodes). Compound 4, derived from a crosslinked fivefold interpenetrated diamond-like substructure, is an unusual example of a self-penetrating coordination framework displaying an unprecedented eight-connected 4(20)6(8) topology with trinuclear cadmium clusters as eight-connected nodes which, to our knowledge, not only defines a new topology for eight-connected coordination networks, but also represents the highest connected topology presently known for self-penetrating systems. Detailed structural comparison of these complexes indicates that the increase in metal nuclearity induces the progressive increase in the connectivities of the ultimate nets: that is, the metal nuclearity plays a significant role in tuning the connectivity of a specific network. The thermal and luminescent properties of these compounds are discussed.

Journal Article↗
PubMed2005

A series of three-dimensional lanthanide coordination polymers with rutile and unprecedented rutile-related topologies.

The complexes of formulas Ln(pydc)(Hpydc) (Ln = Sm (1), Eu (2), Gd (3); H2pydc = pyridine-2,5-dicarboxylic acid) and Ln(pydc)(bc)(H2O) (Ln = Sm (4), Gd (5); Hbc = benzenecarboxylic acid) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, TG analysis, and single-crystal X-ray diffraction. Compounds 1-3 are isomorphous and crystallize in the orthorhombic system, space group Pbcn. Their final three-dimensional racemic frameworks can be considered as being constructed by helix-linked scalelike sheets. Compounds 4 and 5 are isostructural and crystallize in the monoclinic system, space group P2(1)/c. pydc ligands bridge dinuclear lanthanide centers to form the three-dimensional frameworks featuring hexagonal channels along the a-axis that are occupied by one-end-coordinated bc ligands. From the topological point of view, the five three-dimensional nets are binodal with six- and three-connected nodes, the former of which exhibit a rutile-related (4.6(2))(2)(4(2).6(9).8(4)) topology that is unprecedented within coordination frames, and the latter two species display a distorted rutile (4.6(2))(2)(4(2).6(10).8(3)) topology. Furthermore, the luminescent properties of 2 were studied.

Journal Article↗
PubMed2005

Intestinal electric stimulation modulates neuronal activity in the nucleus of the solitary tract in rats.

Intestinal electric stimulation (IES) has been shown to produce an inhibitory effect on gastric motility and secretion. The possible central mechanism of this entero-gastric inhibitory effect induced by IES is unknown. The objective of this study was to evaluate the effects of various IES on the activity of neurons in nucleus tractus solitarii (NTS). We examined the extracellular neuronal activity in NTS of the medulla in pentobarbital anesthetized, paralyzed, ventilated male adult rats. The aortic depressor, superior laryngeal, and carotid sinus nerves were crushed or sectioned bilaterally to avoid neuronal responses in NTS to cardiovascular baroreceptors. After NTS neurons with gastric input were identified, responses of single neurons in NTS to IES were determined. IES with different parameters was performed via a pair of platinum electrodes sutured onto the serosal surface of the duodenum 2 cm below the pylorus. IES with different parameters activated 39--72% of the solitary tract nucleus neurons responsive to gastric distension. Moreover, we demonstrated that IES activated the neuronal activity in NTS, which was stimulation energy dependent. The modulatory effect of IES on the central neurons receiving vagal inputs may contribute to the neural mechanisms of IES therapy for the treatment of patients with obesity and gastrointestinal motility disorders.

Action Potentials↗
PubMed2005

Three-dimensional mesomeric networks assembled from helix-linked sheets: syntheses, structures, and magnetisms.

Two new three-dimensional nickel coordination polymers, [Ni3(BTC)2(4,4'-bpy)2(H2O)5].1.5H2O (1) and [Ni(PDB)(4,4'-bpy)].0.5H2O (2)(4,4'-bpy = bipyridine, BTC = 1,2,4-benzenetricarboxylate, PDB = pyridine-3,4-dicarboxylate), have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, TGA, and single crystal X-ray diffraction. Both compounds contain 2D scaffolding motifs, and most interestingly adjacent scaffolds are connected by infinite helical chains into unique three-dimensional mesomeric networks. Moreover, temperature-dependent magnetic susceptibilities for the two compounds were studied, and ferromagnetic interactions through syn-anti carboxylate bridges between Ni sites have been observed.

Crystallography, X-Ray↗
PubMed2005

Gastric electrical stimulation modulates neuronal activity in nucleus tractus solitarii in rats.

Implantable gastric electric stimulation (GES) has been under investigation for the treatment of gastric motor disorders and obesity. However, possible central mechanisms involving the effects of GES on gastric function are unclear. The purpose of this study was to examine the effects of GES with different parameters on neuronal activity in the nucleus tractus solitarii (NTS) of the medulla. Extracellular potentials of single neurons in NTS were recorded in pentobarbital anesthetized, paralyzed, ventilated male rats. GES with four sets of parameters was applied for one minute: GES-A (6 mA, 0.3 ms, 40 Hz, 2 s-on and 3 s-off), GES-B (20 mA, 0.3 ms, 40 Hz, 2 s-on and 3 s-off), GES-C (6 mA, 6 ms, 40 Hz, 2 s-on and 3 s-off), and GES-D (6 mA, 200 ms, 12 imps/min). 35/118 (30%) neurons in NTS were responsive to gastric distension (GD, 20 mmHg, 20 s). Forty-one percent, 67%, 76% and 42% of all the responsive NTS neurons were affected by GES-A, -B, -C and -D, respectively. More NTS neurons with gastric inputs were affected with GES-C (19/25) than with GES-A (11/27, P<0.05) and GES-D (10/24, P<0.05). Maximal excitatory responses (17.9+/-2.6 imp/s) of NTS neurons to GES-C were significantly greater than GES-D (9.7+/-4.8 imp/s, P<0.05), whereas average duration of excitatory response (74.8+/-4.3 s) of NTS neurons to GES-B was significant longer than GES-A (60.3+/-3.3 s). Gastric electrical stimulation primarily has an excitatory effect on NTS neurons receiving input from the stomach; the central neuronal response to GES is enhanced with stimulation using an increased pulse width and/or amplitude. This modulatory effect of GES on the central neurons receiving vagal inputs may contribute to the neural mechanisms of GES therapy for the treatment of patients with obesity and gastric motility disorders.

Animals↗
PubMed2005

Cross-organ sensitization of lumbosacral spinal neurons receiving urinary bladder input in rats with inflamed colon.

BACKGROUND & AIMS: Clinical studies show that patients with irritable bowel syndrome and colonic diseases frequently experience sensory and motor dysfunctions of the urinary bladder. The aim of this study was to investigate the spinal neuronal mechanisms responsible for potential cross talk between these visceral organs. METHODS: Colonic inflammation was induced by dextran sulfate sodium (5%) in drinking water for 7-12 days (n = 12); another group of rats without dextran sulfate sodium (n = 12) was used as control. Extracellular potentials of single L6 to S2 spinal neurons were recorded in pentobarbital-anesthetized and paralyzed rats with dextran sulfate sodium-induced colitis or normal colon. Urinary bladder distention (0.5-2.0 mL; 20 seconds) was produced with saline inflation, and colorectal distention was induced by inflation of an air balloon (80 mm Hg; 20 seconds). RESULTS: A total of 58 of 153 (38%) and 55 of 152 (36%) spinal neurons responded to urinary bladder distention in dextran sulfate sodium-treated and control animals, respectively. The mean background activity of neurons excited by urinary bladder distention in rats with dextran sulfate sodium-induced colitis was significantly higher than in the control group. The threshold volume for excitatory responses to urinary bladder distention in rats with inflamed colon (0.024 +/- 0.09 mL; n = 30) was significantly lower than for control rats (0.062 +/- 0.016 mL; n = 31; P < .05). The stimulus-response curves of excitatory responses to graded urinary bladder distention were significantly increased for both viscerovisceral (urinary bladder distention and colorectal distention) convergent neurons and urinary bladder distention-receptive neurons in rats with colitis compared with control animals. CONCLUSIONS: Acute colitis sensitized lumbosacral spinal neurons receiving input from the urinary bladder. Thus, spinal neuronal hyperexcitability may be involved in central cross-organ sensitization of visceral nociception between the colon and urinary bladder.

Animals↗