Proton NMR investigation of heme and surrounding proton in low-spin cyanide-ligated bacterial hemoglobin from Vitreoscilla

(1)H NMR spectra of low-spin cyanide-ligated bacterial hemoglobin from Vitreoscilla (VtHb-CN) are reported. The assignments of the(1)H NMR spectra of VtHb-CN have been made through MCOSY, NOESY, 1D TOE and SUPERWEFT experiments. Almost all resonance peaks of heme and ligated His85 are identified. The spin-lattice relaxation time T (1)'s and the variation relationships of chemical shifts of these peaks with temperature have been acquired, from which the distances between the measured protons and Fe(3+), and the diamagnetic chemical shifts have been acquired, respectively. The ionization constants of pK (a)'s of ligated His85 are determined through pH titration of chemical shift, which is 4.95 for ligated His85 C(2)H proton. The lower pK (a) is attributed to the influence of the Fe(3+) of carrying positive charge and the coordination of His85 and Fe(3+) of heme.

[Analysis of Amomun villosum species and some adulterants of zingiberaceae by RAPD]

Different Amomum villosum Lour. species and some their adulterants of Zingiberaceae were researched using RAPD. The PCR indicates favourable differentiation of the reaction. The Amomum villosum Lour. species have the similar DNA fingerprints while it is obviously differ from adulterants. There are 12.17 percent of primers which appear polymorphism. We can identify different species according to these dissimilarity. We also construct the tree of the molecular evolution through NJ software, the hereditary distance of the graph shows different relationships between Amomum villosum Lour. species and their adulterants. The result created by software is analogous the traditional methods.

Exploring the conformational diversity of loops on conserved frameworks

Loops are structurally variable regions, but the secondary structural elements bracing loops are often conserved. Motifs with similar secondary structures exist in the same and different protein families. In this study, we made an all-PDB-based analysis and produced 495 motif families accessible from the Internet. Every motif family contains some variable loops spanning a common framework (a pair of secondary structures). The diversity of loops and the convergence of frameworks were examined. In addition, we also identified 119 loops with conformational changes in different PDB files. These materials can give some directions for functional loop design and flexible docking.

[Surgical management of subglottic carcinoma]

OBJECTIVE

To explore the clinical features and the methods of surgery and functional restoration of subglottic carcinoma.

METHODS

Thirteen cases with primary subglottic carcinoma were treated surgically in this department from 1981 to 1997. Among them, six had T1-2N0 lesions, one had T3N0 lesion and six had T3-4N1-2 lesions. Four cases underwent total laryngectomy and nine had subglottic partial laryngectomy. The extensive subglottic partial laryngectomy was performed on patients with tracheal invasion. The defects of larynx were reconstructed by using unilateral or bilateral pedicled musculocutaneous flap, myofascial flap accordingly. T-shape silastic tube was placed in to the reconstructed cavity of larynx during the operation and the patients were decannulated in 2 to 6 months. Unilateral radical neck dissection was performed on 4 patients and bilateral on 2.

RESULTS

All cases had restored the function of phonation except for 4 who underwent total laryngectomy. Five out of 9 (55.6%) were decannulated. The swallowing function was restored in all patients. The 3-year and 5-year survival rates were 100% and 66.7% in the cases with total laryngectomy, 88.9% and 75.0% with subglottic partial laryngectomy, respectively.

CONCLUSION

It is possible to detect early subglottic carcinoma by using fiberoptic laryngoscopy routinely with the combination of stroboscopy, CT, MRI in male patients over 40 with hoarseness. It is practical that the whole or partial function of larynx could be restored in most cases with subglottic carcinoma after partial laryngectomy or subtotal laryngectomy. Unilateral or bilateral neck dissection should be performed on patients with T3 or T4 lesion. Postoperative radiotherapy is necessary.

Age-related variation in the interstitial tissues of the cardiac conduction system; and autopsy study of 230 Han Chinese

The amount of fatty and fibrous tissues in 230 Han Chinese who died of noncardio-vascular diseases has been studied by a semi-quantitative method and analysed by chi-square test. The results have shown some consistency. Generally, in the sino-atrial node (SAN), fibrosis and fatty influtratin appear only after 40 years of age and increase one grade with every 20 years. The atrio-ventricular node (AVN) showed fatty change after 30 years of age and fibrosis appeared after 60. In the His bundle (HB), fatty infiltration and fibrosis appear after 40 years. The left bundle branch (LBB) showed similar changes. The appearance of fibrosis in the AVN seems to be later than that reported by Lev.

Emerging HIV infections with distinct subtypes of HIV-1 infection among injection drug users from geographically separate locations in Guangxi Province, China

Heroin users from Guangxi province, a southern province of China that borders Vietnam in the south and Yunnan province in China in the west, were studied for prevalence and risk factors for HIV-1 infection. Viral env sequences from HIV-1-positive individuals were also determined for subtypes of HIV-1. The overall HIV prevalence among 227 heroin users was 40%. Most had used drugs for < or = 3 years. Sharing of injection equipment and unprotected sex were significantly associated with HIV-1 infection. Subtypes C and E HIV-1 were detected in infected heroin users and were sharply segregated in two geographic locations: only subtype C was found in a border city with Yunnan province, whereas only subtype E was found in a city bordering northern Vietnam. HIV-1 strains within each subtype were remarkably homogenous, with a mean intersubject DNA distance of 2.32% for subtype E and 1.13% for subtype C, respectively. Phylogenetic analysis of C2-V5 region of Guangxi subtype E env sequences revealed significant clustering with subtype E sequences from southern Vietnam and Cambodia. These results suggest that HIV-1 infection among heroin users in Guangxi represents two emerging epidemics initiated from distinct sources: one from Vietnam and another from Yunnan province. Factors associated with HIV-1 infection were not restricted to injection practices. Unprotected sexual behaviors are likely to increase the probability of HIV transmission beyond this high-risk population. Designing and implementing effective intervention strategies targeted toward both injection drug use and high risk sexual behavior are urgently needed to further reduce HIV-1 spread in China.

Activities of constitutive promoters in Escherichia coli

The in vivo activities of seven constitutive promoters in Escherichia coli have been determined as functions of growth rate in wild-type relA+ spoT+ strains with normal levels of guanosine tetraphosphate (ppGpp) and in ppGpp-deficient DeltarelADeltaspoT derivatives. The promoters include (i) the spc ribosomal protein operon promotor Pspc; (ii) the beta-lactamase gene promotor Pblaof plasmid pBR322; (iii) the PLpromoter of phage lambda; (iv) and (v) the replication control promoters PRNAIand PRNAIIof plasmid pBR322; and (vi) and (vii) the P1 and P2 promoters of the rrnB ribosomal RNA operon. Each strain carried an operon fusion consisting of one of the respective promoter regions linked to lacZ and recombined into the chromosome at the mal locus of a lac deletion strain. The amount of 5'-terminal lacZ mRNA and of beta-galactosidase activity expressed from these promoters were determined by standard hybridization or enzyme activity assays, respectively. In addition, DNA, RNA and protein measurements were used to obtain information about gene dosage, rRNA synthesis and translation rates. By combining lacZ mRNA hybridization data with gene dosage and rRNA synthesis data, the absolute activity of the different promoters, in transcripts/minute per promoter, was determined. In ppGpp-proficient (relA+ spoT+) strains, the respective activities of rrnB P1 and P2 increased 40 and fivefold with increasing growth rate between 0.7 and 3.0 doublings/hour. The activities of Pspc, PL, Pbla, and PRNAIincreased two- to threefold and reached a maximum at growth rates above 2.0 doublings/hour. In contrast, PRNAIIactivity decreased threefold over this range of growth rates. In ppGpp-deficient (DeltarelA DeltaspoT) bacterial strains, the activities of rrnB P1 and P2 promoters both increased about twofold between 1.6 and 3.0 doublings/hour, whereas the activities of Pspc, PL, Pbla, and PRNAI, and PRNAIIwere about constant. To explain these observations, we suggest that the cellular concentration of free RNA polymerase increases with increasing growth rate; for saturation the P1 and P2 rRNA promoters require a high RNA polymerase concentration that is approached only at the highest growth rates, whereas the other promoters are saturated at lower polymerase concentrations achieved at intermediate growth rates. In addition, the data indicate that the respective rrnB P1 and PRNAIIpromoters were under negative and positive control by ppGpp. This caused a reduced activity of rrnB P1 and an increased activity of PRNAIIduring slow growth in wild-type (relA+ spoT+) relative to ppGpp-deficient (DeltarelA DeltaspoT) bacterial strains.

Expression and localisation of dynamin and syntaxin during neural development and neuromuscular synapse formation

The expression and subcellular localisation of dynamin and syntaxin were examined during the periods of motor neuron development and neuromuscular synaptogenesis in the mouse embryo. Both dynamin and syntaxin could be detected by immunoblotting in the spinal cord at embryonic day 10 (E10; 2 days before axon outgrowth) and at all subsequent ages examined. Reverse transcription and polymerase chain reaction (RT-PCR) identified low levels of all three carboxy-terminal splicing forms of dynamin I in spinal cord from as early as E10. During the period of maturation of spinal neurons, from E10 to the first postnatal day (P0), the short carboxy-terminal splicing form of dynamin I (dynamin I*b) was up-regulated, as was dynamin III, relative to dynamin II mRNA. Syntaxin immunostaining became colocalized with the synaptic vesicle protein, SV2, at neuromuscular synapses within 12 hours of the commencement of synapse formation and throughout subsequent development. In contrast, dynamin, which is important for activity-dependent synaptic vesicle recycling and, thus, sustained neurotransmission, could not be detected at most newly formed synapses until several days after synapse formation. The delayed appearance of dynamin at the synapse, thus, heralds the neonatal development of robust synaptic transmission at the neuromuscular junction.

Oxidative folding of reduced and denatured huwentoxin-I

Huwentoxin-I, a neurotoxic peptide with 33 amino acid residues and three disulfide bonds, was used to investigate the pathway of reduction/denaturation and of oxidative folding in small proteins with multiple disulfide bonds. Titration of thiol groups, reversed-phase HPLC, 1D NMR spectroscopy, and biological activity assays were used to monitor the extent of reduction/ denaturation and renaturation of the toxin. The reduction and denaturation of huwentoxin-I resulted in a 100% loss of bioactivity as measured in a mouse phrenic nerve-diaphragm preparation. About 90% of full biological activity could be restored under optimized conditions of oxidative refolding of the reduced peptide. Several reaction conditions employing air oxidation, oxidized and reduced glutathione (GSSG and GSH), and cystine/cysteine were investigated in order to find optimal conditions for renaturation of huwentoxin-I. The best renaturation yield was achieved in 0.1 mM GSSG and 1 mM GSH at pH 8.5 and 4 degrees C over 24 hr. High concentrations of glutathione and high temperatures reduced renaturation yields. Oxidative refolding of huwentoxin-I in air requires about 6 days for maximal yields and is inhibited by EDTA.

Solution structure of the major alpha-amylase inhibitor of the crop plant amaranth

alpha-Amylase inhibitor (AAI), a 32-residue miniprotein from the Mexican crop plant amaranth (Amaranthus hypochondriacus), is the smallest known alpha-amylase inhibitor and is specific for insect alpha-amylases (Chagolla-Lopez, A., Blanco-Labra, A., Patthy, A., Sanchez, R., and Pongor, S. (1994) J. Biol. Chem. 269, 23675-23680). Its disulfide topology was confirmed by Edman degradation, and its three-dimensional solution structure was determined by two-dimensional 1H NMR spectroscopy at 500 MHz. Structural constraints (consisting of 348 nuclear Overhauser effect interproton distances, 8 backbone dihedral constraints, and 9 disulfide distance constraints) were used as an input to the X-PLOR program for simulated annealing and energy minimization calculations. The final set of 10 structures had a mean pairwise root mean square deviation of 0.32 A for the backbone atoms and 1.04 A for all heavy atoms. The structure of AAI consists of a short triple-stranded beta-sheet stabilized by three disulfide bonds, forming a typical knottin or inhibitor cystine knot fold found in miniproteins, which binds various macromolecular ligands. When the first intercystine segment of AAI (sequence IPKWNR) was inserted into a homologous position of the spider toxin Huwentoxin I, the resulting chimera showed a significant inhibitory activity, suggesting that this segment takes part in enzyme binding.

Three-dimensional structure of Selenocosmia huwena lectin-I (SHL-I) from the venom of the spider Selenocosmia huwena by 2D-NMR

The three-dimensional structure of native SHL-I, a lectin from the venom of the Chinese bird spider Selenocosmia huwena, has been determined from two-dimensional 1H NMR spectroscopy recorded at 500 and 600 MHz. The best 10 structures have NOE violation <0.3 A, dihedral violation <2 deg, and average root-mean-square differences of 0.85 + 0.06 A over backbone atoms. The structure consists of a three-stranded antiparallel beta-sheet and three turns. The three disulfide bridges and three-stranded antiparallel beta-sheet form a inhibitor cystine knot motif which is adopted by several other small proteins, such as huwentoxin-I, omega-conotoxin, and gurmarin. The C-terminal fragment from Leu28 to Trp32 adopts two sets of conformations corresponding to the cis and trans conformations of Pro31. The structure of SHL-I also has high similarity with that of the N-terminus of hevein, a lectin from rubber-tree latex.

[The analysis of pathological changes of cardiac conduction system in 54 cases of cardiac sudden deaths]

OBJECTIVE

To elucidate the exact cause of death in cases of cardiac sudden deaths.

METHODS

Sampling of cardiac conduction system (CCS) designed by the research group was adopted. The CCS of 120 cases died of cardiac sudden deaths were collected for routine histological examination.

RESULTS

In 54 out of 120 cases, the causes of death were attributed to lesions present in the CCS, and 85.2% of them were young adults. The peak age range was from 20 - 30. Much more in males (6.7:1). The pathological changes in CCS include: inflammation (46.2%), fatty infiltration, hypertrophic cardiomyopathy associated with CCS changes; hemorrhage, developmental anomalies, fibrosis and tumors.

CONCLUSION

The pathological changes of CCS are relatively common, as the cause of sudden deaths. Which is considered to be the pathological basis of the unstable cardiac electric potentials and arrhythmia. This study recommended the necessity of routine examination on CCS in cases of sudden deaths.

The beta+-thalassemia mutation [IVS-II-5 (G-->C] creates an alternative splicing site in the second intervening sequence

We report a beta-thalassemia mutation [IVS-II-5 (G-->C)] in a Chinese family. Recently we cloned this beta-globin gene and studied its transient expression in murine erythroleukemia (MEL) cells. Both the thalassemic and normal beta-globin genes were isolated by polymerase chain reaction and TA-vector cloning. When the cloned beta-thalassemic globin gene was introduced into MEL cells, two kinds of spliced cytoplasmic beta-globin RNAs were detected. The predominant RNA was normally spliced, while the less abundant RNA contained an insertion of the first 47 nucleotides of the second intervening sequence localized between exons 2 and 3. These results suggest that the mutation [IVS-II-5 (G-->C)] causes a beta+-thalassemia.

[Research on the protective effect of wine against cardiovascular diseases]

Recent studies reveal that wine is rich in phytoalexin and polyphenolic compounds, which can inhibit atherosclerosis by modulating metabolism of plasma lipid and lipoprotein, preventing platelet from aggregation and relaxing cardiovascular smooth muscle, etc.. A long-term moderately intake of wine can reduce the morbidity and mortality of ischemic heart diseases.

Assignment of the three disulfide bonds of Selenocosmia huwena lectin-I from the venom of spider Selenocosmia huwena

The positions of the disulfide bonds of Selenocosmia huwena lectin-I (SHL-I) from the venom of the Chinese bird spider S. huwena have been determined. The existence of three disulfide bonds in the native SHL-I was proved by matrix-assisted laser desorption ionization time-of-flight mass spectroscopic analysis. To map the disulfide bonds, native SHL-I was proteolytically digested. The resulting peptides were separated by reverse phase high-performance liquid chromatography. Matrix-assisted laser desorption ionization time-of-flight mass spectroscopic analysis indicated the presence of one disulfide bond Cys7-Cys19. The partially reduced peptides by using Tris-(2-carboxyethyl)-phosphine at pH 3.0 were purified by reverse phase high-performance liquid chromatography. Four M Guanidine-HCl was found to increase the yields of partially reduced peptides prominently. The free thiols were carboxamidomethlate by iodoacetamide. The specific location of another disulfide bond Cys2-Cys14 was proved by comparing N-terminal sequencing analysis of the partially reduced and alkylated SHL-I with that of the intact peptide. Finally, the three disulfide linkage of SHL-I could be assigned as Cys2-Cys14, Cys7-Cys19, Cys13-Cys26.

[Determination of toxic peptides in Amanita virosa and Amanita verna]

The toxic peptides in Amanita virosa and Amanita verna from various region were analyzed by a reversed-phase high-performance liquid chromatography. It is showed that there were great differences in the concentrations of toxic peptides between species and strains of A. virosa and A. verna.

Reveal, a general reverse engineering algorithm for inference of genetic network architectures

Given the immanent gene expression mapping covering whole genomes during development, health and disease, we seek computational methods to maximize functional inference from such large data sets. Is it possible, in principle, to completely infer a complex regulatory network architecture from input/output patterns of its variables? We investigated this possibility using binary models of genetic networks. Trajectories, or state transition tables of Boolean nets, resemble time series of gene expression. By systematically analyzing the mutual information between input states and output states, one is able to infer the sets of input elements controlling each element or gene in the network. This process is unequivocal and exact for complete state transition tables. We implemented this REVerse Engineering ALgorithm (REVEAL) in a C program, and found the problem to be tractable within the conditions tested so far. For n = 50 (elements) and k = 3 (inputs per element), the analysis of incomplete state transition tables (100 state transition pairs out of a possible 10(15)) reliably produced the original rule and wiring sets. While this study is limited to synchronous Boolean networks, the algorithm is generalizable to include multi-state models, essentially allowing direct application to realistic biological data sets. The ability to adequately solve the inverse problem may enable in-depth analysis of complex dynamic systems in biology and other fields.

Modeling the normal and neoplastic cell cycle with "realistic Boolean genetic networks": their application for understanding carcinogenesis and assessing therapeutic strategies

In this paper we show how Boolean genetic networks could be used to address complex problems in cancer biology. First, we describe a general strategy to generate Boolean genetic networks that incorporate all relevant biochemical and physiological parameters and cover all of their regulatory interactions in a deterministic manner. Second, we introduce "realistic Boolean genetic networks" that produce time series measurements very similar to those detected in actual biological systems. Third, we outline a series of essential questions related to cancer biology and cancer therapy that could be addressed by the use of "realistic Boolean genetic network" modeling.

[A clinicopathological analysis of primitive neuroectodermal tumors of the CNS]

OBJECTIVE

To investigate the difference between cerebellar medulloblastoma (MB) and primary cerebral small cell tumor in histogenesis, morphologic features and biological behavior.

METHODS

210 cases of MB and 9 cases of small cell tumor of cerebrum were observed with histologic and immunohistochemical techniques.

RESULTS

Both tumors were composed of primitive cells with focal evidence of glial and/or neuronal differentiation. In 63.2% of MB and five-eighths of small cell tumor of cerebrum coexpressed GFAP and Syn. Both types of tumors were highly malignant. The overall 1 year survival rates were 34.63% and 25.65% respectively. The survival rate was lower for patients with high proliferative index, with necrosis or without receiving radiation therapy.

CONCLUSION

MB is similar to other small cell tumors of CNS in morphological features, specific marker expression and biological behavior. These tumors can be classified as primitive neuro-ectodermal tumors (PNET).

Molecular characterization of a plant FKBP12 that does not mediate action of FK506 and rapamycin

Immuonosuppressive drugs FK506 and rapamycin block a number of signal transduction pathways in eukaryotic systems. The 12 kDa FK506 binding protein (FKBP12) mediates the action of both FK506 and rapamycin against their functional targets. In this report, we cloned, sequenced and characterized a gene encoding FKBP12 in Vicia faba (VfFKBP12). While VfFKBP12 is highly homologous to animal and yeast FKBP12, it does not mediate the action of FK506 and rapamycin. There are unique features in plant FKBP12 sequences that cause the variation in their function. One lies in the domain that is critical for interaction with calcineurin (CaN), the mammalian and yeast target of FKBP12-FK506 complex. Protein-protein interaction assays revealed a low-affinity and unstable VfFKBP12-FK506-CaN ternary complex. In the genetic assay, VfFKBP12 did not restore the sensitivity of yeast FKBP12 mutant to rapamycin or FK506, supporting that plant FKBP12-ligand complexes are unable to block the function of the drug target. Also unique to plant FKBP12 proteins, a pair of cysteines is spatially adjacent to potentially form disulfide linkage. Treatment of VfFKBP12 with reductant dithiothreitol (DTT) abolished the formation of VfFKBP12-FK506-CaN ternary complex. Site-directed mutagenesis to substitute one of the cysteines, Cys26, with Ser produced a similar effect as DTT treatment. These results indicate that an intramolecular disulfide bond is a novel structural feature required for the low-affinity interaction between plant FKBP12 and CaN. In conclusion, plant FKBP12 proteins have evolved structural changes that modify their protein-protein interacting domains and cause loss of function against the drug targets.

[The pharmacologic research on "shen yang formulae"]

Trough pharmacologic test on seral cholesterol and teral triglycerin in normal mouse fed by high fat food and by hperlipidemia mouse, it is found that "Sen Yang Formulae" has a very good effect on lowering cholesterol and triglycerin, and it also has good effect on promoting quantity of HDL-C, ratio of HDL-C/TC, lowering quantity of LDL-C and improving condition of blood viscosity and fluidity. The results indicate that it is effective on prevention and treatment of hyperlipidemia and benefits at prevention and treatment of arteriosclerosis and coronary heart disease.

[The surgical treatment for the epiglottic cancer extended to the base of tongue]

26 cases of the epiglottic cancer extended to the base of the tongue were studied retrospectively. Among them, 14 were male and 12 female. The age varied from 43 to 62. Besides two cases who underwent total laryngectomy, the other twenty-four were treated with supraglottic horizontal partial laryngectomy or horizontovertical subtotal laryngectomy and resection of part of base of the tongue. 11 cases received bilateral radical neck dissection (RND) and 10 cases unilateral RND simultenously. The results showed twenty-four cases had resumed speaking ability, twenty had been decannulated and restored the laryngeal functions. The 5-year survival rate was 57.9% (12/19). It was concluded that transpharyngeal approach was reasonable for supraglottic horizontal partial laryngectomy associated with the resection of the base of the tongue.