Silencing of crustacean hyperglycemic hormone gene expression reveals the characteristic energy and metabolic changes in the gills and epidermis of crayfish Procambarus clarkii.

The crustacean hyperglycemic hormone (CHH) is a multifaceted neuropeptide instrumental in regulating carbohydrate and lipid metabolism, reproduction, osmoregulation, molting, and metamorphosis. Despite its significance, there is a dearth of research on its metabolic impact on the gills and epidermis-key organs in osmoregulation and molting processes. This study employed CHH dsRNA injections to silence CHH gene expression in Procambarus clarkii, followed by a metabolomic analysis of the gills and epidermis using nuclear magnetic resonance spectroscopy. Metabolic profiling through principal component analysis revealed the most pronounced changes at 24 h post-injection (hpi) in the epidermis and at 48 hpi in the gills. At 24 hpi, the epidermis exhibited significant modulation in 25 enrichment sets and 20 KEGG pathways, while at 48 hpi, 5 metabolite sets and 6 KEGG pathways were prominently regulated. Notably, pathways associated with amino acid metabolism, carbohydrate metabolism, and cofactor and vitamin metabolism were affected. A marked decrease in glucose and other carbohydrates suggested a compromised carbohydrate supply, whereas increased levels of citrate cycle intermediates implied a potential boost in energy provision. The silencing of CHH gene expression hampered the carbohydrate supply, which was possibly the main energy derived substrates. Conversely, the gills displayed significant alterations in 15 metabolite sets and 16 KEGG pathways at 48 hpi, with no significant changes at 24 hpi. These changes encompassed amino acid, carbohydrate, and lipid metabolism pathways. The decline in TCA cycle intermediates pointed to a potential downregulation of the cycle, whereas a decrease in ketone bodies indicated a shift towards lipid metabolism for energy production. Additionally, increased levels of nicotinate, nicotinamide, and quinolinate were observed in both organs. Overall, CHH's impact on the epidermis was prominent at 24 hpi and diminished thereafter, whereas its influence on metabolism in gills was delayed but intensified at 48 hpi. This differential CHH effect between gills and epidermis in P. clarkii provides new insights into the organ-specific regulatory mechanisms of CHH on energy metabolism and osmoregulation, warranting further comparative studies to elucidate the distinct roles of CHH in these organs.

Synthesis and preliminary evaluation of novel 11C-labeled GluN2B-selective NMDA receptor negative allosteric modulators.

N-methyl-D-aspartate receptors (NMDARs) play critical roles in the physiological function of the mammalian central nervous system (CNS), including learning, memory, and synaptic plasticity, through modulating excitatory neurotransmission. Attributed to etiopathology of various CNS disorders and neurodegenerative diseases, GluN2B is one of the most well-studied subtypes in preclinical and clinical studies on NMDARs. Herein, we report the synthesis and preclinical evaluation of two 11C-labeled GluN2B-selective negative allosteric modulators (NAMs) containing N,N-dimethyl-2-(1H-pyrrolo[3,2-b]pyridin-1-yl)acetamides for positron emission tomography (PET) imaging. Two PET ligands, namely [11C]31 and [11C]37 (also called N2B-1810 and N2B-1903, respectively) were labeled with [11C]CH3I in good radiochemical yields (decay-corrected 28% and 32% relative to starting [11C]CO2, respectively), high radiochemical purity (>99%) and high molar activity (>74 GBq/µmol). In particular, PET ligand [11C]31 demonstrated moderate specific binding to GluN2B subtype by in vitro autoradiography studies. However, because in vivo PET imaging studies showed limited brain uptake of [11C]31 (up to 0.5 SUV), further medicinal chemistry and ADME optimization are necessary for this chemotype attributed to low binding specificity and rapid metabolism in vivo.

Pd-Catalyzed Transfer of Difluorocarbene.

The study of transition-metal difluorocarbene complex has long been a subject of active investigation, but the transition-metal-catalyzed transfer of difluorocarbene remains a significant challenge. The Pd-catalyzed transfer of difluorocarbene is described to realize the coupling reaction of boronic acids with difluorocarbene to give (difluoromethyl)arenes and -olefins. Mechanistic investigations reveal that the Pd═CF2 complex is an important intermediate for this transformation. This complex is prone to trimerization without the presence of starting materials.

Difluoromethylation and gem-difluorocyclopropenation with difluorocarbene generated by decarboxylation.

Difluoromethylation of the activated X-H bond (X = N, O and S) and aliphatic thiols, and gem-difluorocyclopropenation of alkynes with difluorocarbene generated in situ from difluoromethylene phosphobetaine (Ph3P(+)CF2CO2(-)) by decarboxylation occurred smoothly without the presence of any base or other additives.

1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU)-promoted decomposition of difluorocarbene and the subsequent trifluoromethylation.

Difluorocarbene derived from various carbene precursors could be effectively decomposed by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). This decomposition process was successfully applied in the subsequent trifluoromethylation of a variety of (hetero)aryl iodides without the addition of an external fluoride ion. Mechanistic investigation revealed the detailed difluorocarbene conversion process in which the decomposed difluorocarbene is finally transformed into a fluoride ion and carbon monoxide.

[Cost-benefit study of different thrombolytic strategies in treating 156 patients with symptomatic pulmonary thromboembolism].

OBJECTIVE: To compare the costs and benefits of different thrombolytic strategies with urokinase (UK) and recombinant tissue plasminogen activator (rt-PA) in treating acute pulmonary thromboembolism (PTE), with aim of providing optimal thrombolytic medication. METHODS: Data from 156 patients with PTE from January 2006 to December 2011 in Tangshan Gongren Hospital was analyzed retrospectively. All patients were treated by thrombolysis, among them 104 patients were treated with 1×10(4) U/kg of UK and 52 patients were treated with 50 mg of rt-PA. The therapeutic effects of two methods were compared and the complication incidence rate and medical cost were also compared. RESULTS: There were no significant differences in the symptom remission rate, the recanalization rate, and the incidence of complications between UK group and rt-PA group (68.2% vs. 71.2%, 63.5% vs. 73.1%, 14.4% vs. 17.3%, all P > 0.05), but the treatment cost (yuan) of UK group was remarkably lower than that of rt-PA group (408 ± 120 vs. 6500 ± 634, P < 0.01). CONCLUSION: Different thrombolytic strategies with UK and rt-PA yield similar efficacy, however, the medical cost was significant decreased in UK group.

[Identification of VP3 antigenic epitopes of infectious bursal disease virus].

Infectious bursal disease virus(IBD) causes infectious bursal disease (IBD), which infects bursal of chicken and can evoke immune suppression. This study identified the antigenic epitopes of four McAbs to IBDV VP3(HRB-3F, HRB-7B, HRB-7C and HRB-10E)with pepscan. A set of 17 partially overlapping or consecutive peptides (P1-P17) spanning VP3 were expressed for epitope screening by pepscan. Finally, two antigenic epitopes, 109-119aa and 177-190aa of IBDV VP3, were identified by Western blot and ELISA. The peptides on epitopes could react with IBDV, and they had better immunnogenicity. The sequences of epitopes were compared with that of several other IBDV strains in the same region, and was found they were totally homologous. This study showed the two epitopes were novel conserved linear B cell epitopes on the VP3 of IBDV. This study provides basis for the development of immunity-based prophylactic, therapeutic and diagnostic measures for control of IBD and further for structural and functional analysis of IBDV.

[Identification and clone of human Alzheimer's disease related gene nicastrin promoter].

OBJECTIVE: To identify the promoter of human nicastrin (NCT) gene, a major component of gamma-secretase which is closely related with pathogenesis of Alzheimer's disease. METHODS: Promoter of human Alzheimer's disease related gene, nicastrin, a 1768 bp fragment was firstly isolated from human genomic DNA by PCR. This fragment's 3 flanking end was 4 bp upstream to the start codon ATG (+1) of the gene. This fragment was used as template, a series of deleted fragments were amplified and constructed to the pGL3-Enhancer plasmid with the artificial designed linkers. The relative activity of their promoter in Hela cells was studied by dual-luciferase assay. RESULTS: The 420 bp fragment showed the strongest activity, and the 237 bp fragment was the minimal fragment in length with activity. CONCLUSION: The promoter of NCT is located at -432/-133 region upstream the translational start codon, while its basal promoter is between -359/-90 that drives the transcription of reporter gene in Hela cells.

Identification of the alternative promoters of the KChIP4 subfamily.

The subfamily of voltage-dependent potassium (Kv) channel interacting protein 4 (KChIP4) is made up of the auxiliary interacting protein of voltage-dependent potassium channels. In this study, the structure of four splicing variants of the human KChIP4 gene was analyzed. Three of the four isoforms of the KChIP4 gene, KChIP4.1, KChIP4.2 and KChIP4.4, were amplified from mouse and human fetal brain tissues by reverse transcription-polymerase chain reaction and then identified. Based on the bioinformatics analysis of the genomic sequences of the gene, we cloned and characterized two promoter fragments from the KChIP4 gene. One was a 325 bp fragment upstream of the 5' end of the KChIP4.1 mRNA sequence and the other was an 818 bp fragment located immediately at the 5' end of the KChIP4.4 variant. Both of them can initiate the transcription of the reporter gene in HT1080 cells and Sprague-Dawley (SD) rat fetal brain neurons, and they contain CG islands, except typical TATA boxes and CAAT boxes. This shows that the KChIP4 gene expression is regulated by an alternative promoter.

[Construction of middle fragment deletion mutant with improved gene splicing by overlap extension].

OBJECTIVE: To construct a phosphatidylinositol 4-kinase beta (PI4K-beta) mutant with the 325th to 373rd amino acid codons deleted, and try to develop a simple method for constructing middle fragment deletion mutant. METHODS: In line with the mechanism of gene splicing by overlap extension(SOE), an additional PCR was used to get the PI4K-beta mutant in which the 325th to 373rd amino acid codons were deleted. Then the mutated gene was cloned into pCMV-Tag4A mammalian expression vector. RESULTS: A mutant with the 325th to 373rd amino acid codons deleted was constructed successfully. CONCLUSION: The improved SOE is a very effective and reliable method to construct middle fragment deletion mutant. It is worthy to be popularized.