Biomedical subjects

Rong Guo

Publications and source records attributed to Rong Guo.

At least 19 recordsLinked to original sources

PubMed2026

Potential of plasma metagenomic next-generation sequencing to guide antibiotic therapy in acute necrotizing pancreatitis with early fever: a prospective multicenter cohort study.

BACKGROUND: Indiscriminate antibiotic use remains common in febrile patients with acute necrotizing pancreatitis (ANP), particularly during the early phase. Metagenomic next‑generation sequencing (mNGS) has shown diagnostic utility for infected pancreatic necrosis (IPN) and may offer a means to guide antimicrobial therapy. We aimed to explore whether mNGS could potentially improve the appropriateness of antibiotic use in ANP patients presenting with early fever. METHODS: This prospective multicenter cohort study was conducted at five hospitals in China, enrolling ANP patients who developed fever within two weeks of symptom onset. Antibiotic susceptibility was defined per local microbiology laboratory reports. The hypothetical impact of mNGS on reducing inappropriate antibiotic use was evaluated through a retrospective simulation using predefined criteria from the BGI China antimicrobial drug usage card, as mNGS results were not disclosed to the treating teams during the actual clinical course. RESULTS: Between May 2023 and December 2024, 125 ANP patients with early fever were enrolled. Antibiotics were administered to 91.2% (114/125) of patients, whereas only 23.2% (29/125)were eventually confirmed to have IPN, and the rate of appropriate antibiotic use was 14.5% (17/117) based on conventional culture. In our simulated model, if therapy had been guided by plasma mNGS results, the estimated rate of appropriate antibiotic use could have increased to 71.8%. CONCLUSIONS: Plasma mNGS facilitates rapid pathogen identification and shows potential for improving antibiotic appropriateness in ANP patients with early fever.

Adult↗

PubMed2026

Genome-wide identification of olfactory receptor and odorant-binding protein gene families and their roles in Heliothine chemosensory evolution.

Chemosensory systems play key roles in the survival and reproductive success of insects. Two large and diverse chemosensory gene families, odorant receptors (ORs) and odorant-binding proteins (OBPs), play critical roles in insect chemosensation and mediate odour-guided behaviours. In the process of insect chemosensation, odorants from the environment pass through pores in the antennal sensilla and become soluble in the sensillar lymph, either directly on contact or by binding to an OBP. Solubilized odour molecules diffuse through the lymph until they reach and activate their cognate ORs, sending electrophysiological signals to the insect brain. To better understand the evolutionary roles of OR and OBP gene families among members of the Heliothinae, we systematically characterized these two gene families in Chloridea virescens (Lepidoptera: Noctuidae). A total of 81 ORs and 49 OBPs were identified genome-wide. Based on the number and positions of conserved cysteine residues, the OBPs were classified into three types: 34 Classic OBPs, 8 Minus-C OBPs and 7 Plus-C OBPs. Phylogenetic analyses identified potential gene duplications and losses within OR and OBP gene families among members of the Heliothinae, which may be associated with differences in their volatile sensation and olfactory behaviours. Further motif and structural analyses identified a conserved region that was unique among pheromone receptors and predicted as key residues of the binding pocket, implying its critical role in pheromone detection. Future work should focus on experimentally validating its function. Overall, our findings provide important insights into how chemosensory gene evolution contributes to ecological adaptation and reproductive isolation in the Heliothine moths.

Animals↗

PubMed2007

Transfer and distribution of L-tryptophan between W/O and O/W, and between W/O and bicontinuous microemulsions through the study of interphase electric properties.

The influence of L-tryptophan (L-Trp) on the interphase electric properties of sodium dodecyl sulfate (SDS)/n-pentanol (n-C(5)H(11)OH)/water (H(2)O) system was studied by the method of AC impedance, and the distribution of L-Trp between the microemulsion phases with different structures in SDS/n-C(5)H(11)OH/H(2)O system was determined by UV-vis spectroscopy. The results show that L-Trp transfers from the lower phase (O/W or bicontinuous) to the upper phase (W/O), and that a small amount of SDS transfers from the upper phase to the lower phase correspondingly with the increase of the total SDS content at a constant weight ratio of n-C(5)H(11)OH/H(2)O=50/50 and a total L-Trp concentration of 1.0 x 10(-4) mol/L. In addition, the concentrations of L-Trp in both the upper and lower phases increase, but the SDS content decreases slightly in the upper phase and increases appreciably in the lower phase with the increase of the total L-Trp concentration at a constant total content of SDS. The interphase capacitance and the interphase charge-transfer current of the system increase, but the interphase resistivity decreases.

Cell Membrane↗

PubMed2006

Combined antioxidant effects of rutin and vitamin C in Triton X-100 micelles.

UV-vis spectra, fluorescence emission spectra and cyclic voltammetric measurements were used to study the influence of Vitamin C on the antioxidant of rutin in Triton X-100 micelles. Rutin can be located in Triton X-100 micelles spontaneously through hydrophobic force, and the binding constant K between rutin and Triton X-100 increases with the rutin concentration. The embedment of two hydroxyl groups on rutin into the more hydrophobic micellar microenvironment makes the oxidation of rutin harder and the radical scavenging activity decrease. With low concentration of Vitamin C, the antioxidant capacity of rutin against hydroxyl radical is enhanced, while that capacity is partly inhibited when the concentration of Vitamin C become higher.

Antioxidants↗

PubMed2006

Matrix metalloproteinase-1 takes advantage of the induced fit mechanism to cleave the triple-helical type I collagen molecule.

The collagenases are members of the matrix metalloproteinase family (MMP) that degrade native triple-helical type I collagen. To understand the mechanism by which these enzymes recognize and cleave this substrate, we studied the substrate specificity of a modified form of MMP-1 (FC) in which its active site region (amino acids 212-254) had been replaced with that of MMP-9 (amino acids 395-437). Although this substitution increased the activity of the enzyme toward gelatin and the peptide substrate Mca-PLGL(Dpa)AR-NH2 by approximately 3- and approximately 11-fold, respectively, it decreased the type I collagenolytic activity of the enzyme to 0.13%. The replacement of Gly233, the only amino acid in this region of FC that is conserved in all collagenase family members, with the corresponding Glu residue in MMP-9 resulted in a substantial decrease in the type I collagenolytic activity of the enzyme without affecting its general proteolytic activities. The kinetic parameters of the FC/G233E mutant for the collagen substrate were similar to those of the chimeric enzyme. In addition, substituting Gly233 for Glu in the chimera increased the collagenolytic activity of the enzyme by 12-fold. Interestingly, replacing Glu415 in MMP-9 with Gly, its corresponding residue in FC, endowed the enzyme with type I collagenolytic activity. The catalytic activity of the MMP-9 mutant toward triple-helical type I collagen was 2-fold higher than that of the collagenase chimera. These data in conjunction with the X-ray crystal structure of FC indicate that Gly233 provides the flexibility necessary for the enzyme active site to change conformation upon substrate binding. The flexibility provided by the Gly residue is essential for type I collagenolytic activity.

Amino Acid Sequence↗

PubMed2006

Acid-base equilibrium of puerarin in CTAB micelles.

Electronic absorption spectra, fluorescence emission spectra, 1HNMR and ab initio quantum calculation are used to study the acid-base equilibrium of puerarin in cetytrimethylammonium bromide (CTAB) micelles with different microstructures and microenvironments. Experiments suggest the microenvironment provided by CTAB micelle cause the acid-base equilibrium of puerarin to move to the deprotonation reaction. The changes in the chemical shifts of the individual groups of protons in CTAB indicate that the location of puerarin changes from the inner to the outer of the CTAB micelles with an increase in puerarin concentration, which enhances the interaction between puerarin and CTAB. The binding of puerarin with CTAB micelle is a spontaneous (deltaG<0) and endothermic process (deltaH<0), and the hydrophobic and electrostatic force is the main driving force for its solubilization.

Algorithms↗

PubMed2006

Interactions between flavonoids and hemoglobin in lecithin liposomes.

In this paper, the binding of flavonoids (quercetin and rutin) to hemoglobin (Hb) have been investigated by fluorescence, absorption spectroscopy and circular dichroism (CD) spectroscopy. The binding parameters and binding mode between flavonoids and Hb are determined and the results of CD and synchronous fluorescence spectra indicate a conformational change of Hb with addition of flavonoids. The effects of lecithin liposomes on the binding parameter of quercetin and rutin to Hb are also studied. When incorporated into liposome, flavonoids can reduce the fluorescence of tryptophanyl residues of Hb to a lesser extent. The difference of the structure characteristics between quercetin and rutin has a significant effect on their binding affinity for Hb.

Circular Dichroism↗

PubMed2006

Autophosphorylation at serine 1987 is dispensable for murine Atm activation in vivo.

The ATM (ataxia telangiectasia mutated) protein kinase is activated under physiological and pathological conditions that induce DNA double-strand breaks (DSBs). Loss of ATM or failure of its activation in humans and mice lead to defective cellular responses to DSBs, such as cell cycle checkpoints, radiation sensitivity, immune dysfunction, infertility and cancer predisposition. A widely used biological marker to identify the active form of ATM is the autophosphorylation of ATM at a single, conserved serine residue (Ser 1981 in humans; Ser 1987 in mouse). Here we show that Atm-dependent responses are functional at the organismal and cellular level in mice that express a mutant form of Atm (mutation of Ser to Ala at position 1987) as their sole Atm species. Moreover, the mutant protein does not exhibit dominant-negative interfering activity when expressed physiologically or overexpressed in the context of Atm heterozygous mice. These results suggest an alternative mode for stimulation of Atm by DSBs in which Atm autophosphorylation at Ser 1987, like trans-phosphorylation of downstream substrates, is a consequence rather than a cause of Atm activation.

Animals↗

PubMed2006

Interaction between flavonoid, quercetin and surfactant aggregates with different charges.

The interactions of flavonoid, quercetin with sodium dodecyl sulfate (anionic surfactant) and cetyltrimethyl ammonium bromide (cationic surfactant) micelles were investigated. The average location site of quercetin in different micelles was determined by the cyclic voltammetry method with the aid of molecular optimization. The interaction parameters of quercetin with micelles of different charges such as binding constant K and normal binding energy DeltaG were calculated. Furthermore, the morphologic change of the SDS and CTAB spherical micelles and rod-like micelles upon their interaction with quercetin was also observed.

Flavonoids↗

PubMed2006

Adsorption characteristics of thionine on gold nanoparticles.

Adsorption characteristics of thionine on gold nanoparticles have been studied by using UV-vis absorption spectroscopy, fluorescence spectroscopy, transmission electron microscopy (TEM), cyclic voltammetry and Fourier transform infrared spectroscopy. With the increasing concentration of gold nanoparticles, the absorption peak intensity of H-type dimers of thionine increases continuously, whereas that of monomers of thionine first increases and then decreases. The addition of gold nanoparticles makes the equilibrium between the monomer and H-type dimer forms of thionine move toward the dimer forms. Furthermore, the adsorption behavior of thionine on gold nanoparticles is also influenced by temperature. TEM images show that the addition of thionine results in an obvious aggregation, and further support the absorption spectral results. The fluorescence intensity of adsorbed thionine is quenched by gold nanoparticles due to the electronic interaction between thionine molecules and gold nanoparticles. Cyclic voltammetric and infrared spectroscopic studies show that the nitrogen atoms of both of the NH2 moieties of thionine strongly bind to the gold nanoparticle surfaces through the electrostatic interaction of thionine with gold nanoparticles. For 15-20 nm particles, the number of adsorbed thionine molecules per gold nanoparticle is about 7.66 x 10(4). Thionine molecules can not only bind to a particle to form a compact monolayer via both of the NH2 moieties, but they can also bind to two particles via their two NH(2) moieties, respectively.

Journal Article↗

PubMed2006

Location of phenothiazine in sodium dodecyl sulfate/n-pentanol/water microemulsions.

The location of phenothiazine (PTZ) in sodium dodecyl sulfate (SDS)/n-pentanol (n-C5H11OH)/water microemulsions is studied by cyclic voltammetry at a Pt electrode. The results indicate that PTZ exists in the membrane phase of microemulsion droplets with its N atom or S atom toward the polar head of the surfactant. In addition, we examine the effect of the compositions and structures of the microemulsions, pH, temperature, and the inorganic salts on the location distribution for PTZ in the membrane phase of the microemulsions. The results show that the location distribution for PTZ in the membrane phase of the microemulsions is mainly dependent on the hydrogen bond between the -NH in PTZ and n-pentanol (or the -SO4- of SDS) and on the electrostatic interaction between the S atom (or N atom) in PTZ and the polar head of SDS.

Journal Article↗

PubMed2006

A pseudoknot in a preactive form of a viral RNA is part of a structural switch activating minus-strand synthesis.

RNA can adopt different conformations in response to changes in the metabolic status of cells, which can regulate processes such as transcription, translation, and RNA cleavage. We previously proposed that an RNA conformational switch in an untranslated satellite RNA (satC) of Turnip crinkle virus (TCV) regulates initiation of minus-strand synthesis (G. Zhang, J. Zhang, A. T. George, T. Baumstark, and A. E. Simon, RNA 12:147-162, 2006). This model was based on the lack of phylogenetically inferred hairpins or a known pseudoknot in the "preactive" structure assumed by satC transcripts in vitro. We now provide evidence that a second pseudoknot (Psi(2)), whose disruption reduces satC accumulation in vivo and enhances transcription by the TCV RNA-dependent RNA polymerase in vitro, stabilizes the preactive satC structure. Alteration of either Psi(2) partner caused nearly identical structural changes, including single-stranded-specific cleavages in the pseudoknot sequences and strong cleavages in a distal element previously proposed to mediate the conformational switch. These results indicate that the preactive structure identified in vitro has biological relevance in vivo and support a requirement for this alternative structure and a conformational switch in high-level accumulation of satC in vivo.

Base Sequence↗

PubMed2006

[Ssh10b2 differs from its paralogue Ssh10b in cellular abundance and the ability to constrain DNA supercoils].

The ssh10b and ssh10b2 genes, a pair of distantly related paralogues in Sulfolobus shibatae, encode members of the Sac10b DNA binding protein family in thermophilic archaea. It has been shown previously that Ssh10b exists in abundance in S. shibatae and is capable of constraining negative DNA supercoils, properties that are consistent with a speculated architectural role for the protein in chromosomal organization. In this study, the ssh10b2 gene was cloned and expressed in Escherichia coli, and the recombinant Ssh10b2 protein was purified to apparent homogeneity. Immunoblotting analysis using a specific anti - Ssh10b2 antibody showed that ssh10b2 was expressed in S. shibatae, but the cellular level of Ssh10b2 was only - 10% of that of Ssh10b. Recombinant Ssh10b2 was capable of interacting with both double-stranded and single-stranded DNA. The affinity of the protein for double-stranded DNA was higher than that reported for Ssh10b. The Ssh10b2 and Ssh10b proteins appeared to generate similar gel shift patterns on duplex DNA fragments. However, unlike Ssh10b, Ssh10b2 was unable to constrain DNA supercoils. These data suggest that Ssh10b2 does not serve as a general architectural factor in DNA compaction and organization in S. shibatae.

Archaeal Proteins↗

PubMed2006

[Mechanism of chondrocyte apoptosis in Kashin-Beck disease and primary osteoarthritis: a comparative study].

OBJECTIVE: To investigate chondrocyte apoptosis and the expressions of Bcl-2, Bax, Fas and iNOS in the articular cartilage between Kashin-Beck disease (KBD) and primary osteoarthritis (OA) and explore the difference in pathogenesis between the two diseases. METHODS: The articular cartilage specimens were collected from 15 normal human subjects, 15 adult patients with KBD and 15 with OA. Chondrocyte apoptosis was detected by TUNEL method, and the expressions of Bcl-2, Bax, Fas and iNOS in articular cartilage were examined with B-SA immunohistochemistry. RESULTS: The percentages of apoptotic chondrocytes positive for TUNEL staining in the articular cartilage were significantly higher in patients with KBD and OA than in normal control subjects (F=20.90-53.16, df=42, P<0.01), and the erosive areas of the articular cartilage contained greater percentage of apoptotic chondrocytes than the non-erosive areas in the same patient with KBD (t=4.154, df=28, P<0.01) or OA (t=6.004, df=28, P<0.01). No significant difference was noted in the positive apoptotic chondrocytes between KBD and OA (t=1.329-1.362, df=28, P>0.05). The percentage of chondrocytes positive for Bcl-2, Bax, Fas and iNOS were significantly higher in KBD and OA patients than in the control subjects (F=25.46-215.31, df=42, P<0.01), and significant differences were observed in Bcl-2, Bax, Fas and iNOS expressions between the erosed areas and non-erosed areas in articular cartilage in patients with KBD (t=2.608-7.77, df=28, P<0.05) and OA (t=2.278-5.413, df=28, P<0.05), but their expressions showed no significant difference between the two diseases (t=0.284-1.590, df=28, P>0.05). CONCLUSION: There was no significant difference in apoptotic chondrocytes and Bcl-2, Bax, Fas and iNOS expressions in the cartilage between adult patients with KBD and OA.

Adult↗

PubMed2006

[Self-rated health status of pregnant and postpartum women].

OBJECTIVE: To To understand the self-rated health of pregnant and postpartum women. METHODS: Using Self-rated Health Measurement Scale Version 1.0 (SRHMS V1.0), health status of 50 reproductive-age nonpregnant women and 55 pregnant women on days 7 and 42 after delivery was assessed. RESULTS: There was statistic significance in daily physical activities, physical mobility and total score of physical health subscale between pregnant women and reproductive-age nonpregnant women (P<0.01). Statistical significance was also found in daily physical activities, physical mobility and total score of physical health subscale as well as total score of the SRHMS V1.0 between women before and 7 days after delivery (P<0.01). The scores of physical mobility, total score of physical health subscale and total score of SRHMS V1.0 showed significant difference between women before and 42 days after delivery (P<0.01). CONCLUSION: Although the physical health status of pregnant women is generally poorer than that of the reproductive-age nonpregnant women, their self-rated health show no significant differences. The self-rated health status of women 7 days after delivery is worse than that before delivery, while such status on days 42 after delivery is obviously better than that before delivery. SRHMS V1.0 provides an effective means for health evaluation of perinatal and postpartum women.

Adult↗

PubMed2005

The interaction of hemoglobin with hexadecyltrimethylammonium bromide.

The interaction of hemoglobin (Hb) with hexadecyltrimethylammonium bromide (CTAB) is investigated by UV-vis absorption spectra and fluorescence spectra method. CTAB monomer can convert methemoglobin (metHb) to hemichrome, and CTAB molecular assemblies, such as micelle, microemulsion and lamellar liquid crystal, can induce heme monomer to leave the hydrophobic cavity of Hb. TEM results show that Hb maintains the spherical structure in CTAB microemulsions while it is unfolded in CTAB lamellar liquid crystals. The existence of proton in the above systems can increase the stability of metHb.

Cetrimonium↗

PubMed2005

Preparation of a highly stable niosome and its hydrotrope-solubilization action to drugs.

Highly stable niosomes are prepared and investigated in Tween80/PEG6000/Span80/H2O system. The mean radius of the niosomes is 0.15-0.2 microm. The contents of PEG6000 and Span80 and the system temperature affect the size and the stability of the niosome. A certain Span80 can remarkably improve the stability. The niosome is provided distinctly with the hydrotrope-solubilization action to the hydrophilic drug and hydrophobic drug, which affects the niosome membrane. The mechanism of the effects of PEG6000 and Span80 on the niosome is discussed in this paper.

Drug Carriers↗

PubMed2005

The interaction between morin and CTAB aggregates.

Electronic absorption spectra, fluorescence emission spectra, ATR-FTIR spectra, cyclic voltammetric measurements, and ab initio quantum calculation are used to study the properties of morin in CTAB micelles with different microstructures and microenvironments and to gain information about the binding of morin with CTAB micelles. Morin can be located in the CTAB micelle with its phenyl group (deviating with 38.98 degrees from the planarity) only in the form of the monomer, which leads to increase of the planarity and extension of the pi conjugation of the whole molecule. The embedding of two hydroxyl groups on the phenyl into a more hydrophobic microenvironment makes the oxidation peak of morin move to a higher potential with a decreased peak current. The binding of morin with CTAB micelles is a spontaneous (DeltaG<0) and endothermic process (DeltaH>0), and the hydrophobic and electrostatic force is the main driving force for its solubilization.

Binding Sites↗