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B Zhang

Publications and source records attributed to B Zhang.

At least 19 recordsLinked to original sources
PubMed2026

Fourier-transform infrared-based genome-wide association study identifies candidate genes and variants for sow colostrum composition.

Sows with high prolificacy and better lactation traits are beneficial for weaned piglet number. Because the genetic basis of sow lactation traits remains elusive, genetic improvement for lactation traits lags behind that for litter traits, constraining the full realisation of genetic potential for large litters. Here, we measured 1&#xa0;060 Fourier-transform infrared (FTIR) wavenumbers and five predicted colostrum composition traits from sow colostrum samples. Heritability estimates for both the FTIR spectra and predicted traits ranged from moderate to high. Correlation analysis revealed that lactose percentage was negatively genetically correlated with the other four predicted traits (fat percentage, protein percentage, total solid content, and urea nitrogen content) and with 24&#xa0;h litter weight, which was positively genetically correlated with both protein and total solid content. Genome-wide association studies on the FTIR spectra and predicted traits identified 134 significant single-nucleotide polymorphisms (SNPs) (False discovery rate < 0.05), with most clustering on Sus scrofa chromosomes (SSC) 5 and 7. Among the candidate genes, two expressed in lactating mammary tissue have established roles in milk trait determination: (1) LALBA, which encodes a major colostrum protein and is responsible for lactose synthesis, and (2) BTN1A1, which mediates milk fat secretion. Additionally, the study detected two important candidate variants on SSC7: (1) rs691487382, which was colocalised with the expression quantitative trait locus signal for TRIM26 in the liver, a key metabolic organ supporting lactation, and (2) rs327923027, a missense variant located in a phylogenetically conserved domain of TRIM26, an E3 ubiquitin ligase implicated in liver homeostasis. Taken together, this study identifies, for the first time, candidate genes and variants for sow colostrum, providing genomic markers useful for genetic improvement.

Association analysis↗
PubMed2001

Frontal affinity chromatography coupled to mass spectrometry for screening mixtures of enzyme inhibitors.

Frontal affinity chromatography coupled online to mass spectrometry (FAC/MS) has previously been used to estimate binding constants for individual protein ligands present in mixtures of compounds. In this study FAC/MS is used to determine enzyme substrate kinetic parameters and binding constants for enzyme inhibitors. Recombinant human N-acetylglucosaminyltransferase V was biotinylated and adsorbed onto immobilized streptavidin in a microcolumn (20 microL). The enzyme was shown to be catalytically competent transferring GlcNAc from the donor UDP-GlcNAc to beta-d-GlcpNAc-(1-->2)-alpha-d-Manp-(1-->6)-beta-d-Glcp-OR acceptor giving beta-d-GlcpNAc-(1-->2)-[beta-d-GlcpNAc-(1-->6)]-alpha-d-Manp-(1-->6)-beta-d-Glcp-OR as the reaction product. The kinetic parameters K(m) and V(max) for the immobilized enzyme could be determined by FAC/MS and were comparable to those measured in solution. Analysis of a mixture of eight trisaccharide analogs in a single run yielded K(d) values for each of the eight compounds ranging from 0.3 to 36 microM. These K(d) values were 2 to 10 times lower than the inhibition constants, K(I)'s, determined in solution using a standard radiochemical assay. However, the ranking order of K(d)'s was the same as the ranking of K(I) values. FAC/MS assays can therefore be employed for the rapid estimation of inhibitor K(d) values making it a valuable tool for enzyme inhibitor evaluations.

Bacterial Capsules↗
PubMed2001

Malignant transformation in a nontumorigenic human prostatic epithelial cell line.

The human prostatic epithelial cell line BPH-1 is normally nontumorigenic in nude mice. The present report demonstrates that this cell line can be permanently transformed by its microenvironment to become tumorigenic. The establishment of a series of tumorigenic sublines based on this parental cell line is described. BPH-1 cells were induced to form tumors either by recombination with human prostatic carcinoma-associated fibroblasts (CAFs) or by exposure to carcinogenic doses of testosterone and estradiol (T+E2) after recombination with rat urogenital sinus mesenchyme. Epithelial cells isolated from these tumors were established as cell strains in culture. When regrafted to nude mouse hosts epithelial cells isolated from CAF- or T+E2-induced tumors were found to be consistently tumorigenic even in the absence of CAF or T+E2. The T+E2-induced cell strains have been designated BPH1(TETD)-A and -B and the CAF-induced strains are designated BPH1(CAFTD)-01 through -08. In vitro, the cells had an epithelial morphology with a less well-defined cobblestone pattern than the parental line. They express SV40 large T antigen, confirming their derivation from the parental BPH-1 line. The BPH1(CAFTD) strains formed colonies in soft agar, whereas the parental BPH-1 cells and the BPH1(TETD) sublines did not. There was no immunocytochemically detectable expression of androgen (AR), alpha-estrogen (ERalpha), or progesterone (PR) receptors by the parental BPH-1 cell line or by any of the tumor-derived cell strains. The cells uniformly coexpressed both basal and luminal cell-type cytokeratins and the basal cell marker p63. When grafted beneath the renal capsule of athymic mouse hosts, all of the tumor-derived cell strains consistently formed tumors. These were predominantly poorly or moderately differentiated squamous or adenosquamous tumors, similar in organization to the primary tumors from which the cell strains were derived. The cell strains continued to express both basal- and luminal-type cytokeratins in vivo. Some of the cell strains also coexpressed vimentin. E-cadherin expression was absent from many of the cells, although patches of cells expressing this marker were seen. The cells continued to express SV40T antigen. These cell strains, which are all derived from a common nontumorigenic progenitor, represent a useful resource for examining genetic and phenotypic changes during carcinogenesis.

Animals↗
PubMed2001

Expressions of neuropilin-1, neuropilin-2 and semaphorin 3A mRNA in the rat brain after middle cerebral artery occlusion.

This study investigated the spatial and temporal expressions of mRNA encoding neuropilin (Npn)-1, Npn-2 and semaphorin3A (Sema3A) in the rat brain after occlusion of the middle cerebral artery (MAC) distal to the striate branches. The expression of Npn-1 mRNA was transiently upregulated in layers V and VI of the parietal cortex not entering infarction on the lesion side from 3 to 6 h after MCA occlusion. The transient up-regulation of Npn-1 mRNA expression was presumably accompanied by an increase in Npn-1 protein as shown by immunohistochemistry in combination with in situ hybridization histochemistry. Intense Npn-2 mRNA expression was noted temporarily in layer II of the parietal cortex on the lesion side from 1 to 6 h after MCA occlusion. The expression of Sema3A mRNA was upregulated in layer VI of the non-infarcted parietal cortex on the lesion side at 6 h after MCA occlusion. The above increases in mRNA expression were no longer observed at 12 h after MCA occlusion. The expressions of Npn-1, -2 and Sema3A mRNA were not detected in the ventroposterior thalamic nucleus undergoing secondary degeneration after MCA occlusion. In the infarct lesion or ischemic core, neuronal expressions of Npn-1, -2 and Sema3A disappeared by 3 days after MCA occlusion as the neurons in situ entered apoptosis or necrosis. In contrast, ED-1-positive microglia/macrophages with Npn-1 and Npn-2 mRNA were observed in the infarct lesion at 1 week after MCA occlusion. These findings suggest that the temporal up-regulation of Npn-1 and Sema 3A mRNA expressions in the non-infarcted parietal cortex on the lesion side is insufficient to induce neuronal cell death possibly because the up-regulated mRNA molecules are not fully translated and that the overexpression of Npn-1 and/or Npn-2 in the ischemic core with degenerating neurons enables activated microglial cells to contact the damaged neurons in situ for phagocytosis.

Animals↗
PubMed2001

Identification of critical staphylococcal genes using conditional phenotypes generated by antisense RNA.

Comprehensive genomic analysis of the important human pathogen Staphylococcus aureus was achieved by a strategy involving antisense technology in a regulatable gene expression system. In addition to known essential genes, many genes of unknown or poorly defined biological function were identified. This methodology allowed gene function to be characterized in a comprehensive, defined set of conditionally growth-defective/lethal isogenic strains. Quantitative titration of the conditional growth effect was performed either in bacterial culture or in an animal model of infection. This genomic strategy offers an approach to the identification of staphylococcal gene products that could serve as targets for antibiotic discovery.

Animals↗
PubMed2001

Multiple CD4+ cell kinetic patterns and their relationships with baseline factors and virological responses in HIV type 1 patients receiving highly active antiretroviral therapy.

This exploratory analyses characterizes patterns of lymphocyte recovery in HIV-1-infected patients treated with highly active antiretroviral therapy (HAART) and investigates their relationship with baseline indices and virologic responses. We modeled kinetics of total CD4+ lymphocytes, as well as naive (CD45RA+ CD62L+), and memory (CD45RA- CD45RO+) subsets in 48 patients treated with AZT/3TC/Ritonavir for 48 weeks in ACTG protocol 315. Cell kinetic indices were estimated by nonlinear regression methods and were correlated with baseline factors and virologic responses. Five different kinetic patterns were identified, including biphasic growth, growth-plateau, growth-depletion, decay-recovery, and biphasic decay. Although overall mean lymphocyte responses showed a biphasic increase in cell number, a careful investigation reveals that only one-third of patients actually followed the biphasic growth pattern in CD4+ cell response, while 44% of 48 patients from this study followed the growth-depletion pattern. CD4+ cell recovery during the first phase and the 48-week study period were negatively correlated with baseline CD4+ cell counts, and positively correlated with baseline viral load. Memory CD4+ cell recovery during the first phase was also negatively correlated with baseline memory CD4+ and total CD4+ cell number, but the recovery rate of memory CD4+ cells during the second phase was positively correlated with baseline CD4+ cell number. Patients with a decay in CD4+ cell count during treatment were more likely to have experienced virological rebound (58%) than patients with nondecay patterns (24%). The rate and magnitude of the absolute increase in total CD4+ and memory CD4+ cell number (but not naive CD4+ cells) during the second phase were lower in patients with viral rebound compared with patients with persistent viral suppression. These results show that the kinetics of lymphocyte reconstitution in response to potent antiretroviral therapy in individual patients vary considerably from the "classic" biphasic increase that characterizes the mean or median response pattern. Pattern analysis of lymphocyte kinetics may be useful for testing relationships among factors that modulate the response to treatment.

Anti-HIV Agents↗
PubMed2001

[Indexes of auditory steady state response initiated by propofol of different concentrations].

OBJECTIVE: To assess the usefulness of auditory steady state response index (ASSR index) in monitoring the depth of sedation with propofol. METHODS: Propofol at the target plasma concentrations of 0.5, 1.0, 1.5 and 2.0 micrograms/ml respectively was administered to 30 ASA grade I-II adult patients to be operated on by computer controlled infusion technique. Two minutes after equilibration of the effect compartment's concentration electively the plasma propofol concentration, the 40 Hz ASSR was recorded immediately at every concentration. Then the infusion was discontinued. When the patients opened their eyes to verbal commands of normal intonation, the 40 Hz ASSR was recorded again. The ASSR index was calculated as the sum of the square root of the absolute difference between every two successive 0.5 ms segments of the auditory steady state response's waveform. The level of sedation was determined by the observer's assessment based on the alertness/sedation scale (OAA/S). The OAA/S score of 2 or less was considered unconscious. RESULT: The amplitudes of Pa and Pb waves and the ASSR index were linearly decreasing with the increase of propofol target concentration and the deepening of level of sedation dose-dependently with the association coefficients as r = 0.780, r = 0.826, and r = 0.759 respectively, P < 0.01. The corresponding regression equations are as follows: Pa = -0.354 x target concentration +1.018, and Pb = -0.468 x target concentration +1.247, ASSR index = -2.924 x target concentration +11.78. The ASSR index reflected the amplitudes of Pa and Pb, especially the amplitude of Pa (r = 0.811 and 0.735 respectively, P < 0.01). In addition, ASSR index was correlated with the depth of patient's sedation (r = 0.815, P < 0.01). When the patients fell asleep from drowsy state, the amplitude of Pa decreased from 0.9 mu v to 0.6 mu v, and the ASSR index decreased from 10.5 to 8.6 with statistical significance (P < 0.05). The patients would not fall asleep until the ASSR index reduced to about 8.5, while reliable unconsciousness happened only when the ASSR index was lower than 5.6. CONCLUSION: ASSR index is useful in monitoring the depth of sedation with propofol. Compared with the amplitudes of Pa and Pb observed traditionally, ASSR index is more accurate and simple and convenient.

Adult↗
PubMed2001

Attenuated neurodegenerative disease phenotype in tau transgenic mouse lacking neurofilaments.

Previous studies have shown that transgenic (Tg) mice overexpressing human tau protein develop filamentous tau aggregates in the CNS. The most abundant tau aggregates are found in spinal cord and brainstem in which they colocalize with neurofilaments (NFs) as spheroids in axons. To elucidate the role of NF subunit proteins in tau aggregate formation and to test the hypothesis that NFs are pathological chaperones in the formation of intraneuronal tau inclusions, we crossbred previously described tau (T44) Tg mice overexpressing the smallest human tau isoform with knock-out mice devoid of NFL (NFL-/-) or NFH (NFH-/-). Depletion of NF subunit proteins from the T44 mice (i.e., T44;NFL-/- and T44;NFH-/-), in particular NFL, resulted in a dramatic decrease in the total number of tau-positive spheroids in spinal cord and brainstem. Concomitant with the reduction in spheroid number, the bigenic mice showed delayed accumulation of insoluble tau protein in the CNS, increased viability, reduced weight loss, and improved behavioral phenotype when compared with the single T44 Tg mice. These results imply that NFs are pathological chaperones in the development of tau spheroids and suggest a role for NFs in the pathogenesis of neurofibrillary tau lesions in neurodegenerative disorders that contain both NFs and tau proteins.

Animals↗
PubMed2001

A human prostatic epithelial model of hormonal carcinogenesis.

The effects of stromal and hormonal environment on the immortalized but nontumorigenic human prostatic epithelial cell line BPH-1 were investigated in an in vivo model. BPH-1 cells were recombined with rat urogenital sinus mesenchyme (UGM), and the tissue recombinants were grafted to the renal capsule of adult male athymic mouse hosts. BPH-1 + UGM recombinants formed solid branching epithelial cords with a well-defined basement membrane. The cords canalized to form ductal structures. The mesenchymal cells formed thick sheets of well-differentiated smooth muscle surrounding the epithelium, reinforcing the idea that the epithelium dictates the patterning of prostatic stromal cells. When hosts carrying BPH-1 + UGM tissue recombinants were exposed to testosterone propionate and 17-beta-estradiol (T + E2), the tissue recombinants responded by forming invasive carcinomas, demonstrating mixed, predominantly squamous as well as adenocarcinomatous (small acinar and mucinous) differentiation. When either untreated or T + E2-treated hosts were castrated, epithelial apoptosis was observed in the grafts. When tumors were removed and regrafted to fresh hosts they grew rapidly. Tumors were serially regrafted through six generations. Histologically these tumors consisted largely of focally keratinizing squamous cell carcinoma with high-grade malignant cytological features. BPH-1 cells grown in the absence of UGM survived at the graft site but did not form tumors or organized structures. This behavior was not influenced by the presence or absence of T + E2 stimulation. These data show that an immortalized, nontumorigenic human prostatic epithelial cell line can undergo hormonal carcinogenesis in response to T + E2 stimulation. In addition, the data demonstrate that the stromal environment plays an important role in mediating hormonal carcinogenesis.

Animals↗
PubMed2001

Controlled nucleation and growth of surface-confined gold nanoparticles on a (3-aminopropyl)trimethoxysilane-modified glass slide: a strategy for SPR substrates.

The thickness of the gold film and its morphology, including the surface roughness, are very important for getting a good, reproducible response in the SPR technique. Here, we report a novel alternative approach for preparing SPR-active substrates that is completely solution-based. Our strategy is based on self-assembly of the gold colloid monolayer on a (3-aminopropyl)trimethoxysilane-modified glass slide, followed by electroless gold plating. Using this method, the thickness of films can be easily controlled at the nanometer scale by setting the plating time in the same conditions. Surface roughness and morphology of gold films can be modified by both tuning the size of gold nanoparticles and agitation during the plating. Surface evolution of the Au film was followed in real time by UV-vis spectroscopy and in situ SPRS. To assess the surface roughness and electrochemical stability of the Au films, atomic force microscopy and cyclic voltammetry were used. In addition, the stability of the gold adhesion is demonstrated by three methods. The as-prepared Au films on substrates are reproducible and stable, which allows them to be used as electrodes for electrochemical experiments and as platforms for studying SAMs.

Journal Article↗
PubMed2001

Intracellular retention of newly synthesized insulin in yeast is caused by endoproteolytic processing in the Golgi complex.

An insulin-containing fusion protein (ICFP, encoding the yeast prepro-alpha factor leader peptide fused via a lysine-arginine cleavage site to a single chain insulin) has been expressed in Saccharomyces cerevisiae where it is inefficiently secreted. Single gene disruptions have been identified that cause enhanced immunoreactive insulin secretion (eis). Five out of six eis mutants prove to be vacuolar protein sorting (vps)8, vps35, vps13, vps4, and vps36, which affect Golgi<-->endosome trafficking. Indeed, in wild-type yeast insulin is ultimately delivered to the vacuole, whereas vps mutants secrete primarily unprocessed ICFP. Disruption of KEX2, which blocks intracellular processing to insulin, quantitatively reroutes ICFP to the cell surface, whereas loss of the Vps10p sorting receptor is without effect. Secretion of unprocessed ICFP is not based on a dominant secretion signal in the alpha-leader peptide. Although insulin sorting mediated by Kex2p is saturable, Kex2p functions not as a sorting receptor but as a protease: replacement of Kex2p by truncated secretory Kex2p (which travels from Golgi to cell surface) still causes endoproteolytic processing and intracellular insulin retention. Endoproteolysis promotes a change in insulin's biophysical properties. B5His residues normally participate in multimeric insulin packing; a point mutation at this position permits ICFP processing but causes the majority of processed insulin to be secreted. The data argue that multimeric assembly consequent to endoproteolytic maturation regulates insulin sorting in the secretory pathway.

Amino Acid Sequence↗
PubMed2001

High-throughput microfabricated CE/ESI-MS: automated sampling from a microwell plate.

A new design for high-throughput microfabricated capillary electrophoresis/electrospray mass spectrometry (CE/ ESI-MS) with automated sampling from a microwell plate is presented. The approach combines a sample-loading port, a separation channel, and a liquid junction, the latter for coupling the device to the MS with a miniaturized subatmospheric electrospray interface. The microdevice was attached to a polycarbonate manifold with external electrode reservoirs equipped for electrokinetic and pressure-fluid control. A computer-activated electropneumatic distributor was used for both sample loading from the microwell plate and washing of channels after each run. Removal of the electrodes and sample reservoirs from the microdevice structure significantly simplified the chip design and eliminated the need both for drilling access holes and for sample/buffer reservoirs. The external manifold also allowed the use of relatively large reservoirs that are necessary for extended time operation of the system. Initial results using this microfabricated system for the automated CE/ESI-MS analysis of peptides and protein digests are presented.

Amino Acid Sequence↗
PubMed2001

Lactation and breast cancer risk: a case-control study in Connecticut.

In this report, we examined the relationship between lactation and breast cancer risk, in a case-control study of breast cancer, conducted in Connecticut between 1994 and 1998. Included were 608 incident breast cancer cases and 609 age frequency matched controls, aged 30-80 years old. Cases and controls were interviewed by trained study interviewers, using a standardized, structured questionnaire, to obtain information on lactation and other major risk factors. Parous women who reported ever lactation had a borderline significantly reduced risk of breast cancer (OR = 0.83, 95% CI, 0.63-1.09). An OR of 0.53 (95% CI, 0.27-1.04) was observed in those having breastfed more than 3 children compared to those who never lactated. Women having breastfed their first child for more than 13 months had an OR of 0.47 (95% CI, 0.23-0.94) compared to those who never breastfed. Lifetime duration of lactation also showed a risk reduction while none of the ORs were statistically significant. Further stratification by menopausal status showed a risk reduction related to lactation for both pre- and postmenopausal women, while the relationship is less consistent for the latter. These results support an inverse association between breastfeeding and breast cancer risk.

Adult↗
PubMed2001

Short-chain fatty acid derivatives stimulate cell proliferation and induce STAT-5 activation.

Current chemotherapeutic and butyrate therapeutics that induce fetal hemoglobin expression generally also suppress erythropoiesis, limiting the production of cells containing fetal hemoglobin (F cells). Recently, selected short-chain fatty acid derivatives (SCFADs) were identified that induce endogenous gamma-globin expression in K562 cells and human burst-forming units-erythroid and that increase proliferation of human erythroid progenitors and a multilineage interleukin-3-dependent hematopoietic cell line. In this report, gamma-globin inducibility by these SCFADs was further demonstrated in mice transgenic for the locus control region and the entire beta-globin gene locus in a yeast artificial chromosome and in 2 globin promoter-reporter assays. Conditioned media experiments strongly suggest that their proliferative activity is a direct effect of the test compounds. Investigation of potential mechanisms of action of these SCFADs demonstrates that these compounds induce prolonged expression of the growth-promoting genes c-myb and c-myc. Both butyrate and specific growth-stimulatory SCFADs induced prolonged signal transducer and activator of transcription (STAT)-5 phosphorylation and activation, and c-cis expression, persisting for more than 120 minutes, whereas with IL-3 alone phosphorylation disappeared within minutes. In contrast to butyrate treatment, the growth-stimulating SCFADs did not result in bulk histone H4 hyperacetylation or induction of p21(Waf/Cip), which mediates the suppression of cellular growth by butyrate. These findings suggest that the absence of bulk histone hyperacetylation and p21 induction, but prolonged induction of cis, myb, myc, and STAT-5 activation, contribute to the cellular proliferation induced by selected SCFADs.

Animals↗
PubMed2001

Determination of alcohols by high-performance liquid chromatography with fluorimetric detection after pre-column derivatisation with carbazole-9-N-acetic acid and chromatographic behaviour of alcoholic derivatives.

Alcohols were derivatised to their carbazole-9-N-acetic acid (CRA) esters with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC.HCl) as the dehydrating agent. Studies on derivatisation conditions indicated that the coupling reaction proceeded rapidly and smoothly in the presence of a base catalyst in acetonitrile to give the corresponding sensitively fluorescent derivatives. The retention behaviour of alcohol derivatives was investigated by varying mobile phase compositions (ACN-water and MeOH-water). The parameters from the equation log k'=A-BX were evaluated by retention data of derivatives using an isocratic elution with different mobile phases. The results indicated that the parameters derived allowed computation of retention factors in good agreement with experiments. At the same time, a general equation was derived that makes possible predictions of partition coefficient in binary mobile phases with different proportions of organic solvent to water based on some simple regression analysis. The LC separation for the derivatised alcohols containing higher carbon alcohols showed good reproducibility on a reversed-phase C18 column with gradient elution. The detection limits (excitation at 335 nm, emission at 360 nm) for derivatised alcohols (signal-to-noise ratio=3:1) were in the range of 0.1-0.4 pg per injection.

Alcohols↗
PubMed2001

A novel all helix fold of the AP180 amino-terminal domain for phosphoinositide binding and clathrin assembly in synaptic vesicle endocytosis.

Clathrin-mediated endocytosis plays a major role in retrieving synaptic vesicles from the plasma membrane following exocytosis. This endocytic process requires AP180 (or a homolog), which promotes the assembly and restricts the size of clathrin-coated vesicles. The highly conserved 33 kDa amino-terminal domain of AP180 plays a critical role in binding to phosphoinositides and in regulating the clathrin assembly activity of AP180. The crystal structure of the amino-terminal domain reported herein reveals a novel fold consisting of a large double layer of sheets of ten alpha helices and a unique site for binding phosphoinositides. The finding that the clathrin-box motif is mostly buried and lies in a helix indicates a different site and mechanism for binding of the domain to clathrins than previously assumed.

Adaptor Proteins, Vesicular Transport↗
PubMed2001

Synthesis of 5'-deoxy-5'-thioguanosine-5'-monophosphorothioate and its incorporation into RNA 5'-termini.

[figure: see text] 5'-Deoxy-5'-thioguanosine-5'-monophosphorothioate (GSMP) was synthesized in four steps with 35% overall yield. GSMP serves as a good substrate for in vitro transcription with T7 RNA polymerase to yield 5'-GSMP-RNA, which was converted to 5'-HS-RNA by dephosphorylation with alkaline phosphatase. The thiol-reactive agents can be efficiently introduced into the 5'-terminus of RNA.

DNA-Directed RNA Polymerases↗