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Jinhua Zhang

Publications and source records attributed to Jinhua Zhang.

At least 19 recordsLinked to original sources
PubMed2006

A strategy for annotating the human milk glycome.

Oligosaccharides in human milk represent a group of bioactive molecules that have evolved to be an abundant and diverse component of human milk, even though they have no direct nutritive value to the infant. A recent hypothesis proposes that they could be substrates for the development of the intestinal microflora and the mucosal immune system. The inability to determine the exact composition of these oligosaccharides limits research and the ability to understand their biological functions. Oligosaccharides isolated from the lipids and proteins of individual human milk samples were analyzed by a combination of techniques including microchip liquid chromatography mass spectrometry (HPLC-Chip/MS) and matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FT ICR MS). Accurate mass measurements obtained using an orthogonal time-of-flight (o-TOF) mass spectrometry provided oligosaccharide composition for approximately 200 individual molecular species. Comparison of HPLC-Chip/MS profiles from five different women revealed variations in milk oligosaccharide compositions. HPLC-Chip/MS profiling provides a method for routinely identifying milk oligosaccharides. Tandem MS in combination with exoglycosidase digestion provides unambiguous differentiation of structural isomers.

Chromatography, High Pressure Liquid↗
PubMed2005

Structural analysis of kappa-carrageenan [corrected] sulfated oligosaccharides by positive mode nano-ESI-FTICR-MS and MS/MS by SORI-CID.

Structural analysis of sulfated oligosaccharides from kappa-carrageenan of up to ten residues (MW >2 kDa) was successfully carried out by positive mode nano-ESI-FTICR-MS together with MS/MS using sustained off-resonance irradiation-collision induced dissociation (SORI-CID). Glycosidic bond cleavage reactions via the B- and Y-types of fragmentation were observed and enabled complete sequencing of the oligosaccharide samples. The positions of the labile sulfate substituents were observable using SORI-CID, enabling the determination of the sequence of the sulfated residues.

Carbohydrate Sequence↗
PubMed2005

Atmospheric pressure MALDI Fourier transform mass spectrometry of labile oligosaccharides.

An atmospheric pressure matrix-assisted laser desorption/ionization (AP MALDI) source coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT ICR MS) under UV laser and solid matrix conditions has been demonstrated to analyze a variety of labile oligosaccharides including O-linked and N-linked complex glycans released from glycoproteins. Spectra were acquired by both AP MALDI and vacuum MALDI and directly compared. The results presented here confirm that AP MALDI can generate significantly less energetic ions than vacuum MALDI and is able to produce the intact molecular ions with little or no fragmentation in both positive and negative ion mode analyses. Under certain conditions, noncovalent complexes of sialylated oligosaccharides were observed. The sensitivity attainable by AP MALDI was found to be comparable to conventional MALDI, and tandem mass spectrometry of oligosaccharides ionized by AP MALDI was shown to allow detailed structural analysis. Analysis of N-glycan mixtures derived from human fibrinogen further demonstrated that AP MALDI-FT ICR MS is ideal for the study of complex glycan samples as it provides high-accuracy, high-resolution mass analysis with no difficulty in distinguishing sample constituents from fragment ions.

Atmospheric Pressure↗
PubMed2005

Sonic hedgehog has a dual effect on the growth of retinal ganglion axons depending on its concentration.

The stereotypical projection of retinal ganglion cell (RGC) axons to the optic disc has served as a good model system for studying axon guidance. By both in vitro and in vivo experiments, we show that a secreted molecule, Sonic hedgehog (Shh), may play a critical role in the process. It is expressed in a dynamic pattern in the ganglion cell layer with a relatively higher expression in the center of the retina. Through gel culture and stripe assays, we show that Shh has a dual effect on RGC axonal growth, acting as a positive factor at low concentrations and a negative factor at high concentrations. Results from time-lapse video microscopic and stripe assay experiments further suggest that the effects of Shh on axons are not likely attributable to indirect transcriptional regulation by Shh. Overexpression of Shh protein or inhibition of Shh function inside the retina resulted in a complete loss of centrally directed projection of RGC axons, suggesting that precise regulation of Shh level inside the retina is critical for the projection of RGC axons to the optic disc.

Age Factors↗
PubMed2005

Mycobacterium tuberculosis infection and FHIT gene alterations in lung cancer.

Although it is fairly well accepted that pulmonary tuberculosis is a major risk factor of lung cancer, the exact molecular mechanisms involved in its tumorigenesis are unclear. For this purpose, we have examined the relationship between Mycobacterium tuberculosis (M-TB) infection and FHIT gene alteration in lung cancer. Tumors with M-TB infection had a slightly higher abnormal FHIT protein expression compared with tumors without M-TB infection, although not statistically significant (Fisher's exact test, P=0.248). LOH affecting at least one locus of the FHIT gene was significantly more frequent in lung cancer patients with M-TB infection than in patients without M-TB infection whether assessment by univariate testing methods or logistic regression modeling analysis (Fisher's exact test P=0.025, logistic regression analysis P=0.012). These results indicate that M-TB infection is associated with FHIT gene LOH in lung cancer.

Acid Anhydride Hydrolases↗
PubMed2005

Infrared multiphoton dissociation of O-linked mucin-type oligosaccharides.

Oligosaccharides are known to play important roles in many biological processes. In the study of oligosaccharides, collision-induced dissociation (CID) is the most common dissociation method to elucidate the sequence and connectivity. However, a disadvantage of CID is the decrease in both the degree and efficiency of dissociation with increasing mass. In the present study, we have successfully performed infrared multiphoton dissociation (IRMPD) on 39 O-linked mucin-type oligosaccharide alditols (both neutral and anionic). CID and IRMPD spectra of several oligosaccharides were also compared. They yielded nearly identical fragment ions corresponding to the lowest energy fragmentation pathways. The characteristic fragmentations of structural motifs, which can provide the linkage information, were similarly presented in both CID and IRMPD spectra. Multistage of CID (MS(3) or MS(4)) is commonly needed to completely sequence the oligosaccharides, while IRMPD of the same compounds yielded the fragment ions corresponding to the loss of the first residue to the last residue during a single-stage tandem MS (MS(2)). Finally, it is shown that the fragmentation efficiency of IRMPD increases with the increasing size of oligosaccharides.

Mucins↗
PubMed2005

CD11b may be a less satisfactory indicator for cardiac ischemia-reperfusion injury in coronary artery bypass graft surgery with cardiopulmonary bypass than cardiac troponin I.

STUDY OBJECTIVE: To investigate whether CD11b on neutrophils can be used as a marker to predict myocardial ischemia-reperfusion injury for patients undergoing coronary artery bypass graft (CABG) surgery on cardiopulmonary bypass (CPB). DESIGN: Prospective, observational study. SETTING: University teaching hospital and university hospital laboratories. PATIENTS: Twelve adults, physical status II and III (American Society of Anesthesiologists) patients scheduled for elective CABG surgery on CPB. INTERVENTIONS: Anesthesia and surgical interventions were performed according to standard procedures. Coronary sinus was cannulated for retrograde cardioplegia perfusion and for coronary sinus blood sampling. The blood samples were collected from systemic and coronary venous sinus blood respectively at several time points before CPB, during CPB, and after declamping of the ascending aorta. MEASUREMENTS AND MAIN RESULTS: CD11b expressions in systemic circulation blood increased significantly during CPB and maintained higher levels after cardiac reperfusion (P < .05); on the other hand, CD11b expressions in coronary sinus blood declined gradually and reached their lowest level at 5 minutes after aortic declamping. The differences in CD11b expressions between systemic circulatory blood and coronary sinus blood after cardiac reperfusion were significant (P < .05). Cardiac troponin I (cTnI) concentrations in both systemic circulatory blood and coronary sinus blood increased significantly after cardiac reperfusion (P < .05), and the concentrations of cTnI in coronary sinus blood increased much higher than the corresponding concentrations of cTnI at each time point (P < .05). CONCLUSION: CD11b expression on neutrophils may not be a reliable predictor for myocardial ischemia-reperfusion injury in CABG surgery on CPB because of the possible sequestration of neutrophils in myocardium.

Adult↗
PubMed2004

Profiling the morphological distribution of O-linked oligosaccharides.

The morphological distribution of oligosaccharides is determined in the egg jelly surrounding Xenopus laevis eggs. This biological system is used to illustrate a method for readily identifying and quantifying oligosaccharides in specific tissues. The extracellular matrix surrounding X. laevis eggs consists of a vitelline envelope and a jelly coat. The jelly coat contains three morphologically distinct layers designated J1, J2, and J3 from the innermost to the outermost and is composed of 9-11 distinct glycoproteins. Each jelly layer is known to have specific functions in the fertilization of the egg. We developed a rapid method to separate and identify the oligosaccharides from X. laevis egg jelly layers. Identification was based on the retention times in high-performance liquid chromatography (porous graphitized carbon column), exact masses, and tandem mass spectrometry. Over 40 neutral and 30 sulfated oligosaccharides were observed in the three jelly layers. Neutral oligosaccharide structures from different jelly layers were both unique and overlapping, while sulfated oligosaccharides were detected only in layers J1 and J2. Neutral oligosaccharides unique to jelly layer J3 and the combined layers J1+J2 had similar core structures and similar residues. However, differences between these two sets of unique oligosaccharides were also observed and were primarily due to the branching carbohydrate moieties rather than the core structures.

Animals↗
PubMed2004

Strategy for profiling and structure elucidation of mucin-type oligosaccharides by mass spectrometry.

A strategy combining accurate mass determination, tandem mass spectrometry, structure homology, and exoglycosidases is described that allows the structural characterization of mucin-type O-linked oligosaccharides. The method is used to profile with quantitation the O-linked oligosaccharide (both neutral and anionic) components of the only diploid Xenopus frog, Xenopus tropicalis. Collision-induced dissociation was used to determine connectivity, to identify previously characterized oligosaccharides, and to determine the presence of structural motifs in unknown oligosaccharides. Exoglycosidase digestion was used to identify the individual residues along with the linkages. The enzymes were also used to cleave larger oligosaccharides to smaller units that are similar to previously elucidated components. By using CID, isomeric structures were compared to determine whether they were identical. In this way, the exoglycosidases were more effectively used, and their use was minimized. A total of 35 oligosaccharides including neutral, sialylated, and sulfated were characterized in this way. The relative abundances of all components were also determined based on HPLC.

Animals↗
PubMed2004

Method for the comparative glycomic analyses of O-linked, mucin-type oligosaccharides.

A method is presented for the direct relative quantitation of distinct O-linked mucin-type oligosaccharides. Mucin-type oligosaccharides are found in a host of tissues from anuran to humans. Because they are often associated with extracellular matrix, they play important roles in cell-cell recognition. Changes in glycosylation of O-linked oligosaccharides are associated with diseases such as cancer. In fertilization, they play an active role in sperm-egg recognition. We describe a method for observing changes in glycosylation of mucin-type oligosaccharides by incorporating deuterium in the release procedure. Oligosaccharides from two different sources are released separately by sodium tetrahydroborate and sodium tetradeuterioborate. The oligosaccharides are combined and separated into components by HPLC. By observing the ratio of deuterated and undeuterated species, changes in glycosylation are precisely quantified. This method is illustrated with mucin-type oligosaccharides from the egg jelly coat of the anuran Xenopus laevis.

Animals↗
PubMed2004

Encoding method for OBOC small molecule libraries using a biphasic approach for ladder-synthesis of coding tags.

In the "one-bead one-compound" (OBOC) combinatorial library method, each compound bead displays only one compound entity. Hundreds of thousands to millions of compound beads can be synthesized rapidly and screened simultaneously. Positive compound beads are then isolated for structural analysis. To fully exploit the power of OBOC combinatorial small molecule libraries, a robust and high throughput encoding method is needed to decode the positive compound beads. In this paper, we report on the development of a novel encoding strategy that combines the concepts of ladder-synthesis and chemical encoding on bilayer beads. In these encoded libraries, small molecule compounds are displayed on the bead surface, and cleavable coding tags consisting of a series of truncated molecules reside in the bead interior. Such a library can be easily constructed using the biphasic approach (J. Am. Chem. Soc.2002, 124, 7678) to topologically segregate the functionalities of the beads during library synthesis. The ladder members and coding tags are then released for MALDI-TOF-MS analysis. To simplify the interpretation of the mass spectra, we purposely add bromine into the cleavable linker so that the cleavage products generate a characteristic isotope fingerprint. The chemical structure of library compounds can be determined by analyzing the mass differences between adjacent peaks on the mass spectra. This encoding strategy also provides valuable information on the quality of the testing compound on the surface of the bead. To validate this methodology, a model OBOC small molecule library with 12,288 members was synthesized on TentaGel beads and screened against streptavidin. The chemical structures of the compound on each positive bead were unambiguously identified.

Amino Acids↗
PubMed2004

Disruption of gradient expression of Zic3 resulted in abnormal intra-retinal axon projection.

The targeting of retinal ganglion axons toward the optic disc is the first step in axon pathfinding in the visual system. The molecular mechanisms involved in guiding the retinal axons to project towards the optic disc are not well understood. We report that a gene encoding a zinc-finger transcription factor, Zic3, is expressed in a periphery-high and center-low gradient in the retina at the stages of active axon extension inside the retina. The gradient expression of Zic3 recedes towards the periphery over the course of development, correlating with the progression of retinal cell differentiation and axonogenesis. Disruption of gradient expression of Zic3 by retroviral overexpression resulted in mis-targeting of retinal axons and some axons misrouted to the sub-retinal space at the photoreceptor side of the retina. Misexpression of Zic3 did not affect neurogenesis or differentiation inside the retina, or grossly alter retinal lamination. By stripe assay, we show that misexpression of Zic3 may induce the expression of an inhibitory factor to the retinal axons. Zic3 appears to play a role in intra-retinal axon targeting, possibly through regulation of the expression of specific downstream genes involved in axon guidance.

Animals↗
PubMed2004

Synthesis of hydrophilic and flexible linkers for peptide derivatization in solid phase.

Four N-Fmoc protected polyoxyethylene-based amino acid type linkers were designed and synthesized for peptide derivatization in solid phase. Three of them were obtained in a crystalline form. The crystallized linkers can be stored at 4 degrees C for 2 years without significant decomposition. Protocols for biotinylation and fluorescent labeling of peptides in solid phase were developed. The linkers also provide good ionization ability for single-bead mass spectrometry analysis of peptides.

Biotinylation↗
PubMed2004

Dynamic changes of the CT perfusion parameters in the embolic model of cerebral ischemia.

To study the dynamic changes of CT perfusion parameters during the first 12 h in the embolic cerebral ischemia models. Local cerebral ischemia model were established in 7 New Zealand white rabbits. All CT scans were performed with a GE Lightspeed 16 multislice CT. Following the baseline scan, further CT perfusion scans were performed at the same locations 20 min, 1-6 h and 8, 10 and 12 h after the embolus delivery. Maps of all parameters were obtained by CT perfusion software at each time point. The brains, taken 12 h after the scan, were sliced corresponding to the positions of the CT slices and stained by 2,3,5-triphenyltetrazolium chloride (TTC). On the basis of the TTC results, the ischemic sides were divided into 3 regions: core, penumbra and the relatively normal region. The changes of all parameters were then divided into 3 stages. In the first two hours (the first stage), the CBV dropped more remarkably in the core than in the penumbra but rose slightly in the relatively normal region while the CBF decreased and MTT, TTP extended in all regions to varying degrees. In the 2nd-5th h (the second stage), all the parameters fluctuated slightly around a certain level. In the 5th-12th h (the third stage), the CBV and CBF dropped, and MTT and TTP were prolonged or shortened slightly in the core and penumbra though much notably in the former while the CBV, CBF rose and MTT, TTP were shortened remarkably in the relatively normal region. We experimentally demonstrated that the location and extent of cerebral ischemia could be accurately assessed by CT perfusion imaging. The pathophysiology of the ischemia could be reflected by the CT perfusion to varying degrees.

Animals↗
PubMed2003

A novel and rapid encoding method based on mass spectrometry for "one-bead-one-compound" small molecule combinatorial libraries.

A novel and efficient encoding method based on mass spectrometry for "one-bead-one-compound" small molecule combinatorial libraries has been developed. The topologically segregated bifunctional resin beads with orthogonal protecting groups in the outer and inner regions are first prepared according to our previously published procedure. Prior to library synthesis, the inner core of each bead is derivatized with 3-4 different coding blocks on a cleavable linker. Each functional group on the scaffold is encoded by an individual coding block containing a functional group with the same chemical reactivity. During the library synthesis, the same chemical reactions take place on the scaffold (outer layer of the bead) and coding blocks (inner core of the bead) concurrently. After screening, the coding tags in the positive beads are released, followed by molecular mass determination using matrix-assisted laser desorption ionization Fourier transform mass spectrometry. The chemical structure of library compounds can be readily identified according to the molecular masses of the coding tags. The feasibility and efficiency of this approach were demonstrated by the synthesis and screening of a model small molecule library containing 84 672 member compounds, with a model receptor, streptavidin. Streptavidin binding ligands with structural similarity (17) were identified. The decoding results were clear and unambiguous.

Combinatorial Chemistry Techniques↗
PubMed2003

Irx4-mediated regulation of Slit1 expression contributes to the definition of early axonal paths inside the retina.

Although multiple axon guidance cues have been discovered in recent years, little is known about the mechanism by which the spatiotemporal expression patterns of the axon guidance cues are regulated in vertebrates. We report that a homeobox gene Irx4 is expressed in a pattern similar to that of Slit1 in the chicken retina. Overexpression of Irx4 led to specific downregulation of Slit1 expression, whereas inhibition of Irx4 activity by a dominant negative mutant led to induction of Slit1 expression, indicating that Irx4 is a crucial regulator of Slit1 expression in the retina. In addition, by examining axonal behavior in the retinas with overexpression of Irx4 and using several in vivo assays to test the effect of Slit1, we found that Slit1 acts positively to guide the retinal axons inside the optic fiber layer (OFL). We further show that the regulation of Slit1 expression by Irx4 is important for providing intermediate targets for retinal axons during their growth within the retina.

Animals↗