Interactions of the fucose-specific Pseudomonas aeruginosa lectin, PA-IIL, with mammalian glycoconjugates bearing polyvalent Lewisa and ABH blood group glycotopes

Pseudomonas aeruginosa Fuc > Man specific lectin, PA-IIL, is an important microbial agglutinin that might be involved in P. aeruginosa infections in humans. In order to delineate the structures of these lectin receptors, its detailed carbohydrate recognition profile was studied both by microtiter plate biotin/avidin-mediated enzyme-lectin-glycan binding assay (ELLSA) and by inhibition of the lectin-glycan interaction. Among 40 glycans tested for binding, PA-IIL reacted well with all human blood group ABH and Le(a)/Le(b) active glycoproteins (gps), but weakly or not at all with their precursor gps and N-linked gps. Among the sugar ligands tested by the inhibition assay, the Le(a) pentasaccharide lacto-N-fucopentaose II (LNFP II, Galbeta1-3[Fucalpha1-4]GlcNAcbeta1-3Galbeta1-4Glc) was the most potent one, being 10 and 38 times more active than the Le(x) pentasaccharide (LNFP III, Galbeta1-4 [Fucalpha1-3]GlcNAcbeta1-3Galbeta1-4Glc) and sialyl Le(x) (Neu5Acalpha2-3Galbeta1-4[Fucalpha1-3] GlcNAc), respectively. It was 120 times more active than Man, while Gal and GalNAc were inactive. The decreasing order of PA-IIL affinity for the oligosaccharides tested was: Le(a) pentaose > or = sialyl Le(a) tetraose > methyl alphaFuc > Fuc and Fucalpha1-2Gal (H disaccharide)>2'-fucosyllactose (H trisaccharide), Le(x) pentaose, Le(b) hexaose (LNDFH I) and gluco-analogue of Le(y) tetraose (LDFT)>H type I determinant (LNFP I)>Le(x) trisaccharide (Galbeta1-4[Fucalpha1-3]GlcNAc) > sialyl Le(x) trisaccharide >> Man >>> Gal, GalNAc, and Glc (inactive). The results presented here, in accordance with the crystal 3D structural data, imply that the combining site of PA-IIL is a small cavity-type best fitting Fucalpha1- with a specific shallow groove subsite for the remainder part of the Le(a) saccharides, and that polyvalent glycotopes enhance the reactivity. The Fuc > Man Ralstonia solanacearum lectin RSL, which resembles PA-IIL in sugar specificity, differs from it in it's better fit to the B and A followed by H oligosaccharides vs. Fuc, whereas, the second R. solanacearum lectin RS-IIL (the structural homologue of PA-IIL) binds Man > Fuc. These results provide a valuable information on PA-IIL interactions with mammalian glycoforms and the possible spectrum of attachment sites for the homing of this aggressive bacterium onto the target molecules. Such information might be useful for the antiadhesive therapy of P. aeruginosa infections.

Modified step-theory for investigating mode coupling mechanism in photonic crystal waveguide taper

In this paper, the mathematical model of the modified step-theory is derived based on the platform of two-dimensional photonic crystal structure that is infinitely long in third dimension. The mode coupling mechanism of photonic crystal tapers is theoretically studied using the modified step-theory. The model is verified by comparing the transmission spectrum obtained for the input/output defect coupler where it shows a good match of less than 5% discrepancy. The modified step-theory is applied to different taper structures to investigate the power loss during the transmission. The power loss at the relative position of the taper provides an explanation as to which taper designs give the highest coupling efficiency.

Laccase production by Monotospora sp., an endophytic fungus in Cynodon dactylon

The effects of the carbon and nitrogen sources, initial pH and incubation temperature on laccase production by the endophytic fungus Monotospora sp. were evaluated. The optimal temperature and initial pH for laccase production by Monotospora sp. in submerged culture were found to be 30 degrees C and 8.5, respectively. Maltose (2 g l(-1)) and ammonium tartrate (10 g l(-1)) were the most suitable carbon and nitrogen source for laccase production. Under optimal culture medium, the maximum laccase activity was determined to be 13.55 U ml(-1), which was approximately four times higher than that in basal medium. This is the first report on laccase production by an endophytic fungus.

Grain yield responses to moisture regimes in a rice population: association among traits and genetic markers

Drought is a major constraint to rice (Oryza sativa L.) production in rainfed and poorly irrigated environments. Identifying genomic regions influencing the response of yield and its components to water deficits will aid our understanding of the genetic mechanism of drought tolerance (DT) of rice and the development of DT varieties. Grain yield (GY) and its components of a recombinant inbred population developed from a lowland rice and an upland rice were investigated under different water levels in 2003 and 2004 in a rainout DT screening facility. Correlation and path analysis indicated that spikelet fertility (SF) was particularly important for grain yield with direct effect (P=0.60) under drought stress, while spikelet number per panicle (SN) contributed the most to grain yield (P=0.41) under well-watered condition. A total of 32 quantitative trait loci (QTLs) for grain yield and its components were identified. The phenotypic variation explained by individual QTLs varied from 1.29% to 14.76%. Several main effect QTLs affecting SF, 1,000-grain weight (TGW), panicle number (PN), and SN were mapped to the same regions on chromosome 4 and 8. These QTLs were detected consistently across 2 years and under both water levels in this study. Several digenic interactions among yield components were also detected. The identification of genomic regions associated with GY and its components under stress will be useful to improve drought tolerance of rice by marker-aided approaches.

Structural genomics efforts at the Chinese Academy of Sciences and Peking University

Structural genomics efforts at the Chinese Academy of Sciences and Peking University are reported in this article. The major targets for the structural genomics project are targeted proteins expressed in human hematopoietic stem/progenitor cells, proteins related to blood diseases and other human proteins. Up to now 328 target genes have been constructed in expression vectors. Among them, more than 50% genes have been expressed in Escherichia coli, approximately 25% of the resulting proteins are soluble, and 35 proteins have been purified. Crystallization, data collection and structure determination are continuing. Experiences accumulated during this initial stage are useful for designing and applying high-throughput approaches in structural genomics.

All- trans- retinoic acid-induced erythema nodosum in patients with acute promyelocytic leukemia

Erythema nodosum associated with all- trans-retinoic acid (ATRA) for acute promyelocytic leukemia (APL) is very rare. We describe four patients with classic APL who developed erythema nodosum during ATRA therapy. Fever and subsequent multiple painful erythematous nodules over extremities developed on D11, D16, D17, and D19, respectively, after ATRA therapy. The skin biopsy taken from each patient was consistent with erythema nodosum. All patients received short course of steroids. Fever subsided rapidly and the skin lesions regressed completely. All patients achieved complete remission without withdrawal of ATRA. ATRA seemed to be the most possible etiology of erythema nodosum in our patients. Short-term use of steroid is very effective in ATRA-induced erythema nodosum.

Biohydrogen production by mesophilic fermentation of food wastewater

Batch experiments were conducted to convert molasses wastewater (10-160 g COD/L) into hydrogen at 35 degrees C at various pH (4-8). The maximum hydrogen productivity (HP) and hydrogen production rate (HPR) reached 47.1 mmol-H2/g COD(re) and 97.5 mmol-H2/L-day, respectively, at a substrate concentration of 40 g COD/L and pH 6.0. The methane-free biogas contained up to 50% (v/v) of hydrogen. Fermentation at wastewater concentrations higher than 60 g COD/L required a long acclimation period (more than 20 h). Though the fractions were substrate concentration and pH-dependent, acetate and butyrate were the two main liquid fermentation products. A comparison of the HP and HPR data indicates that defining a hydrogen yield indicator to evaluate hydrogen generation efficiency should be taken into consideration in practical fermentation operations.

[Evaluation of prevalent status of kala-azar in endemic area of Hubei Province]

OBJECTIVE

To identify the diagnosis of 14 cases with "kala-azar" previously reported in Hubei Province since 1989 and to evaluate the present status of the disease.

METHODS

Bone marrow smear, immunological test (LDTand IFAT), mouse inoculation, fungi culture, vector (Phlebotomus) and reservoir host (dog) survey.

RESULTS

Among the 14 cases, 12 cases were progressive disseminated histoplasmois, one was an imported case and another one was a remnant skin type "kala-azar" case. An immunological survey was conducted during 1997-1999 in 25 townships located in 23 counties of 9 prefectures and cities. A total of 13,890 persons had been examined by LDT, the positive rate was 0.07%, no positive case was found among the persons under 40 years of age. During the survey, 1,756 persons had been examined by IFAT, the results were negative. No Phlebotomus chinensis had been found in the surveyed area. A total of 302 dogs were examined, no sick dog had been found.

CONCLUSION

Kala-azar has been eradicated in Hubei Province.

[Effects of Lagenidium giganteum on the activities of three enzymes of Culex quinquefasciatus larvae]

OBJECTIVE

To investigate the possible mechanism underlying the killing of Culex quinquefasciatus larvae by Lagenidium giganteum from the biochemical point of view.

METHODS

The activities of alkaline phosphatase(AKP), acid phosphatase(ACP) and esterase(EST) were observed by using calcium-cobalt method, lead nitrate method and naphthol method. Results were photomicrographed and analysed quantitatively by image analysis using computer.

RESULTS

The activities of AKP and ACP were decreased while the activities of EST were increased among the infected groups with different infection intensities.

CONCLUSIONS

The changes of these enzyme activities might be one of the important mechanisms of action of Lagenidium giganteum against Culex quinquefasciafus larvae.

Surface-roughness wakefield measurements at brookhaven accelerator test facility

An experiment has been carried out at the Brookhaven Accelerator Test Facility to investigate the effect of a surface-roughness wakefield in narrow beam tubes with artificially created bumps. The measurements show that the synchronous modes decay significantly due to the randomization of the roughness pattern. It is pointed out that this decay mechanism has not been investigated in the previous experiment at DESY and the investigators' conclusion does not apply for surface-roughness wakefields in real surfaces.

Tests for Gaussianity of the MAXIMA-1 cosmic microwave background map

Gaussianity of the cosmological perturbations is one of the key predictions of standard inflation, but it is violated by other models of structure formation such as cosmic defects. We present the first test of the Gaussianity of the cosmic microwave background (CMB) on subdegree angular scales, where deviations from Gaussianity are most likely to occur. We apply the methods of moments, cumulants, the Kolmogorov test, the chi(2) test, and Minkowski functionals in eigen, real, Wiener-filtered, and signal-whitened spaces, to the MAXIMA-1 CMB anisotropy data. We find that the data, which probe angular scales between 10 arcmin and 5 deg, are consistent with Gaussianity. These results show consistency with the standard inflation and place constraints on the existence of cosmic defects.

Synaptic connections between trigemino-parabrachial projection neurons and gamma-aminobutyric acid- and glycine-immunoreactive terminals in the rat

The synaptic connections between gamma-aminobutyric acid (GABA)- and glycine-immunoreactive terminals and neurons projecting to the lateral parabrachial region were examined by a combination of retrograde tracing and immunohistochemical staining in the rat medullary dorsal horn. After injection of horseradish peroxidase (HRP) into the right lateral parabrachial region, HRP retrogradely labeled neurons were observed bilaterally in laminae I, II and III of the medullary dorsal horn with an ipsilateral predominance. GABA- and glycine-like immunoreactive terminals were found in laminae I, II and III. Some of these GABA- and glycine-like immunoreactive terminals were observed chiefly to make symmetric synapses with HRP-labeled neuronal cell bodies and dendritic processes. The present results indicate that neurons in the medullary dorsal horn projecting to the lateral parabrachial region might be modulated by GABAergic and glycinergic inhibitory intrinsic neurons, which might be significantly involved in the regulation of the noxious information transmission.

Influence of CETP gene variation on plasma lipid levels and coronary heart disease: a survey in Taiwan

Cholesteryl ester transfer protein (CETP) transfers cholesteryl ester from high-density lipoprotein (HDL) to very low-density lipoprotein (VLDL), low-density lipoprotein (LDL) and chylomicron in exchange for triglycerides. Two CETP genetic variation and four polymorphisms are investigated by polymerase chain reaction (PCR) and restriction enzyme digestion in a population of Taiwan. The results show that a very rare variation frequency is found for CETP intron 14 splice site G-->A change. The population shows a predominant 405Ile allele (61%), 442Asp (97.7%), intron 1Taq1B(+) G allele (52%), intron 8 Msp1(-) A allele (89%) and intron 9 EcoN1(-) T allele (59.2%) in the control group. Patients with coronary heart disease (CHD) have more CETP EcoN1(+/+) GG genotype (25.3%) than the controls (13.6%) (P=0.049). The intron 1 Taq1B(-) A allele is associated with a high HDL cholesterol and apoA1 level, the EcoN1(+) G allele with a low apoA1 level and the 442Gly with both high total cholesterol and LDL cholesterol levels. Paradoxically, the 442Gly is also present with a higher frequency (5.2%) in HDL cholesterol > or =65 mg/dl group than that in the general population (2.3%) (P=0.04).

Hyperbaric oxygen treatment decreases post-ischemic neurotrophin-3 mRNA down-regulation in the rat hippocampus

The therapeutic effect of hyperbaric oxygen (HBO) on ischemic injury was investigated using in situ hybridization to detect the mRNA expression of neurotrophin-3 (NT-3), which is thought to play a crucial role in protecting against neuronal death induced by brain ischemia. The rats under investigation were subjected to 10 min transient forebrain ischemia, and subsequently exposed to HBO (100% oxygen, 2.5 atm absolute) for 2 h. Levels of NT-3 mRNA in the CA1, CA2 and CA3 regions, and the dentate gyrus of the hippocampus were measured after various reperfusion periods. Neuronal death in the hippocampal CA1 region was also measured by Nissl staining, seven days post ischemia. The results demonstrated that HBO treatment significantly reduced the ischemia-induced down-regulation of the NT-3 mRNA level at 4 h post ischemia, and significantly increased cell survival 7 days after reperfusion. The findings suggest that an HBO treatment maintaining the NT-3 mRNA level in the hippocampus can be beneficial to the ischemic brain within a certain time frame.

Antitumor Agents. 211. Fluorinated 2-phenyl-4-quinolone derivatives as antimitotic antitumor agents

Fluorinated 2-phenyl-4-quinolone derivatives were synthesized and evaluated in National Cancer Institute's 60 human tumor cell line in vitro screen. From the results, the ketone moiety plays an essential role in activity. Among the compounds tested, 2'-fluoro-6-pyrrol-2-phenyl-4-quinolone (13) exhibited the most potent cytotoxic activities (log GI(50) < -8.00) against renal and melanoma tumor cell lines. Compound 13 was also a potent inhibitor of tubulin polymerization (IC(50) = 0.46 microM) and of radiolabeled colchicine binding to tubulin, with activities comparable to those of the potent antimitotic natural products colchicine, podophyllotoxin, and combretastatin A-4.

Carbohydrate specificity of a galectin from chicken liver (CG-16)

Owing to the expression of more than one type of galectin in animal tissues, the delineation of the functions of individual members of this lectin family requires the precise definition of their carbohydrate specificities. Thus, the binding properties of chicken liver galectin (CG-16) to glycoproteins (gps) and Streptococcus pneumoniae type 14 polysaccharide were studied by the biotin/avidin-mediated microtitre-plate lectin-binding assay and by the inhibition of lectin-glycan interactions with sugar ligands. Among 33 glycans tested for lectin binding, CG-16 reacted best with human blood group ABO (H) precursor gps and their equivalent gps, which contain a high density of D-galactopyranose(beta1-4)2-acetamido-2-deoxy-D-glucopyranose [Gal(beta1-4)GlcNAc] and Gal(beta1-3)GlcNAc residues at the non-reducing end, but this lectin reacted weakly or not at all with A-,H-type and sialylated gps. Among the oligosaccharides tested by the inhibition assay, the tri-antennary Gal(beta1-4)GlcNAc (Tri-II) was the best. It was 2.1x10(3) nM and 3.0 times more potent than Gal and Gal(beta1-4)GlcNAc (II)/Gal(beta1-3)GlcNAc(beta1-3)Gal(beta1-4)Glc (lacto-N-tetraose) respectively. CG-16 has a preference for the beta-anomer of Gal at the non-reducing end of oligosaccharides with a Gal(beta1-4) linkage >Gal(beta1-3)> or =Gal(beta1-6). From the results, it can be concluded that the combining site of this agglutinin should be a cavity type, and that a hydrophobic interaction in the vicinity of the binding site for sugar accommodation increases the affinity. The binding site of CG-16 is as large as a tetrasaccharide of the beta-anomer of Gal, and is most complementary to lacto-N-tetraose and Gal(beta1-4)GlcNAc related sequences.

Carbohydrate specificity of a toxic lectin, abrin A, from the seeds of Abrus precatorius (jequirity bean)

To elucidate of the mechanism of intoxication, the affinity of a toxic lectin, abrin A, from the seeds of Abrus precatorius for mammalian carbohydrate ligands, was studied by enzyme linked lectinosorbent assay and by inhibition of abrin A-glycan interaction. From the results, it is concluded that: (1) abrin A reacted well with Gal beta1-->4GlcNAc (II), Gal alpha1-->4Gal (E), and Gal beta1-->3GalNAc (T) containing glycoproteins. But it reacted weakly with sialylated gps and human blood group A,B,H active glycoproteins (gps); (2) the combining site of abrin A lectin should be of a shallow groove type as this lectin is able to recognize from monosaccharides with specific configuration at C-3, C-4, and deoxy C-6 of the (D)Fuc pyranose ring to penta-saccharides and probably internal Gal alpha,beta-->; and (3) its binding affinity toward mammalian structural features can be ranked in decreasing order as follows: cluster forms of II, T, B/E (Gal alpha1-->3/4Gal) > monomeric T > monomeric II > monomeric B/E, Gal > GalNAc > monomeric I >> Man and Glc (inactive). These active glycotopes can be used to explain the possible structural requirements for abrin A toxin attachment.

Carbohydrate specificity of a lectin isolated from the fungus Sclerotium rolfsii

In order to investigate the functional roles of a phytopathogenic fungal lectin (SRL) isolated from the bodies of Sclerotium rolfsii, the binding properties of SRL were studied by enzyme linked lectinosorbent assay and by inhibition of SRL-glycan interaction. Among glycoproteins (gp) tested for binding, SRL reacted strongly with GalNAc alpha1-->4Ser/Thr (Tn) and/or Gal beta1-->3GalNAc alpha1-->(T(alpha)) containing gps: human T(alpha) and Tn glycophorin, asialo salivary gps, and asialofetuin, but its reactivity toward sialylated glycoproteins was reduced significantly. Of the sugar ligands tested for inhibition of SRL-asialofetuin binding, Thomsen-Friedenreich residue (T(alpha)) was the best, being 22.4 and 2.24 x 10(3) more active than GalNAc and Gal beta1--> residues, respectively. Other ligands tested were inactive. When the glycans used as inhibitors, T(alpha), and/or Tn containing gps, especially asialo PSM, asialo BSM, asialo OSM, active antifreeze gp, asialo glycophorin and Tn-glycophorin were very active, and 1.0 x 10(4) times more potent than GalNAc. From these results, it is clear that the combining site of SRL should be of a cavity type and recognizes only Tn and T(alpha) residues of glycans; it is suggested that T(alpha) and Tn glycotopes, which are present only in abnormal carbohydrate sequences of higher orders of mammal, are the most likely sites for phytopathogenic fungal attachment as an initial step of infection. The affinity of SRL for ligands can be ranked in decreasing order as follows: multivalent T(alpha) and Tn >> monomeric T(alpha) and Tn > GalNAc >>> II (Gal beta1-->4GlcNAc), L (Gal beta1-->4Glc), and Gal.

Antioxidant activity of extracts from Acacia confusa bark and heartwood

The antioxidant activity of extracts from bark and heartwood of Acacia confusa was evaluated by various antioxidant assays, including free radical and superoxide radical scavenging assays and lipid peroxidation assay as well as hydroxyl radical-induced DNA strand scission assay. In addition, an ex vivo antioxidant assay using a flow cytometric technique was also employed in this study. The results indicate that both bark and heartwood extracts clearly have strong antioxidant effects. Similar inhibitory activities for each test sample were found for both 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical generation and lipid peroxidation. As for the superoxide radical scavenging activity, the heartwood extract was more effective than the bark extract. Furthermore, the heartwood extract protected PhiX174 supercoiled DNA against strand scission induced by ultraviolet photolysis of H2O2, and it reduced the amounts of intracellular hydrogen peroxide, a reactive oxygen species, when it was co-incubated with human promyelocytic leukemia (HL-60) cells under oxidative stress.

Further characterization of apolipoprotein B genetic variations in Taiwanese

Apolipoprotein B (apoB, protein; APOB, gene) is the main protein component of low-density lipoprotein (LDL) and plays an important role in blood lipid metabolism. Previously, we have reported four APOB coding regions, 5' signal peptide, and 3' repeat sequence polymorphisms in our population. In this report, we further characterize other APOB genetic variations. The results illustrate that the mutation frequencies for Arg3500Gln (1/846 alleles), Arg4019Trp (2/786 alleles), -265 C/T promoter region (0/264 alleles), and intron 2 A/G (0/450 alleles) are very low. Our population showed a frequency of 68.9% for the B4311 Ser allele. The B4311 Asn allele was associated with a higher apoB level than the Ser group (p < 0.05) in normal controls. In the normal controls, a higher B4311 Asn/Asn genotype frequency was found in the group with total cholesterol (TC) > 200 mg/dL and apoB concentration > 85 mg/dL than in the group with a TC < 200 mg/dL and apoB < 85 mg/dL (p = 0.03 for TC comparison).

Cosmology from MAXIMA-1, BOOMERANG, and COBE DMR cosmic microwave background observations

Recent results from BOOMERANG-98 and MAXIMA-1, taken together with COBE DMR, provide consistent and high signal-to-noise measurements of the cosmic microwave background power spectrum at spherical harmonic multipole bands over 2<l less similar to 800. Analysis of the combined data yields 68% (95%) confidence limits on the total density, Omega(tot) approximately 1.11+/-0.07 (+0.13)(-0.12), the baryon density, Omega(b)h(2) approximately 0.032(+0.005)(-0.004) (+0.009)(-0.008), and the scalar spectral tilt, n(s) approximately 1.01(+0.09)(-0.07) (+0.17)(-0.14). These data are consistent with inflationary initial conditions for structure formation. Taken together with other cosmological observations, they imply the existence of both nonbaryonic dark matter and dark energy in the Universe.

Identification of a novel steroid derivative, NSC12983, as a paclitaxel-like tubulin assembly promoter by 3-D virtual screening

By flexibly docking 9593 compounds of the NCI-3D database against the refined structure of beta-tubulin using DOCK 4.0, a long-forgotten synthetic steroid derivative, NSC12983, has been identified as a microtubule-stabilizing agent. The 32 top scorers includes NSC12983 and the three added references: paclitaxel, docetaxel and IDN5109. That is, 12.5% of the 0.33% top scorers are active. In addition, NSC12983 is active on Mycobacterium tuberculosis in vitro and in vivo, which might be due to its ability to promote the assembly of essential cell division protein.

Solution structure of a type I dockerin domain, a novel prokaryotic, extracellular calcium-binding domain

The type I dockerin domain is responsible for incorporating its associated glycosyl hydrolase into the bacterial cellulosome, a multienzyme cellulolytic complex, via its interaction with a receptor domain (cohesin domain) of the cellulosomal scaffolding subunit. The highly conserved dockerin domain is characterized by two Ca(2+)-binding sites with sequence similarity to the EF-hand motif. Here, we present the three-dimensional solution structure of the 69 residue dockerin domain of Clostridium thermocellum cellobiohydrolase CelS. Torsion angle dynamics calculations utilizing a total of 728 NOE-derived distance constraints and 79 torsion angle restraints yielded an ensemble of 20 structures with an average backbone r.m.s.d. for residues 5 to 29 and 32 to 66 of 0.54 A from the mean structure. The structure consists of two Ca(2+)-binding loop-helix motifs connected by a linker; the E helices entering each loop of the classical EF-hand motif are absent from the dockerin domain. Each dockerin Ca(2+)-binding subdomain is stabilized by a cluster of buried hydrophobic side-chains. Structural comparisons reveal that, in its non-complexed state, the dockerin fold displays a dramatic departure from that of Ca(2+)-bound EF-hand domains. A putative cohesin-binding surface, comprised of conserved hydrophobic and basic residues, is proposed, providing new insight into cellulosome assembly.