Key determinants for signaling in the sensory rhodopsin II/transducer complex are different between Halobacterium salinarum and Natronomonas pharaonis

The cell membrane of Halobacterium salinarum contains a retinal-binding photoreceptor, sensory rhodopsin II (HsSRII), coupled with its cognate transducer (HsHtrII), allowing repellent phototaxis behavior for shorter wavelength light. Previous studies on SRII from Natronomonas pharaonis (NpSRII) pointed out the importance of the hydrogen bonding interaction between Thr204NpSRII and Tyr174NpSRII in signal transfer from SRII to HtrII. Here, we investigated the effect on phototactic function by replacing residues in HsSRII corresponding to Thr204NpSRII and Tyr174NpSRII . Whereas replacement of either residue altered the photocycle kinetics, introduction of any mutations at Ser201HsSRII and Tyr171HsSRII did not eliminate negative phototaxis function. These observations imply the possibility of the presence of an unidentified molecular mechanism for photophobic signal transduction differing from NpSRII-NpHtrII.

Interhelical interactions between D92 and C218 in the cytoplasmic domain regulate proton uptake upon N-decay in the proton transport of Acetabularia rhodopsin II

Acetabularia rhodopsin II (ARII or Ace2), an outward light-driven algal proton pump found in the giant unicellular marine alga Acetabularia acetabulum, has a unique property in the cytoplasmic (CP) side of its channel. The X-ray crystal structure of ARII in a dark state suggested the formation of an interhelical hydrogen bond between C218^ARII and D92^ARII, an internal proton donor to the Schiff base (Wada et al., 2011). In this report, we investigated the photocycles of two mutants at position C218^ARII: C218A^ARII which disrupts the interaction with D92^ARII, and C218S^ARII which potentially forms a stronger hydrogen bond. Both mutants exhibited slower photocycles compared to the wild-type pump. Together with several kinetic changes of the photoproducts in the first half of the photocycle, these replacements led to specific retardation of the N-to-O transition in the second half of the photocycle. In addition, measurements of the flash-induced proton uptake and release using a pH-sensitive indium-tin oxide electrode revealed a concomitant delay in the proton uptake. These observations strongly suggest the importance of a native weak hydrogen bond between C218^ARII and D92^ARII for proper proton translocation in the CP channel during N-decay. A putative role for the D92^ARII-C218^ARII interhelical hydrogen bond in the function of ARII is discussed.

Existence of two O-like intermediates in the photocycle of Acetabularia rhodopsin II, a light-driven proton pump from a marine alga

A spectrally silent change is often observed in the photocycle of microbial rhodopsins. Here, we suggest the presence of two O intermediates in the photocycle of Acetabularia rhodopsin II (ARII or also called Ace2), a light-driven algal proton pump from Acetabularia acetabulum. ARII exhibits a photocycle including a quasi-equilibrium state of M, N, and O (M⇄N⇄O→) at near neutral and above pH values. However, acidification of the medium below pH ~5.5 causes no accumulation of N, resulting in that the photocycle of ARII can be described as an irreversible scheme (M→O→). This may facilitate the investigation of the latter part of the photocycle, especially the rise and decay of O, during which molecular events have not been sufficiently understood. Thus we analyzed the photocycle under acidic conditions (pH ≤ 5.5). Analysis of the absorbance change at 610 nm, which mainly monitors the fractional concentration changes of K and O, was performed and revealed a photocycle scheme containing two sequential O-states with the different molar extinction coefficients. These photoproducts, termed O₁ and O₂, may be even produced at physiological pH, although they are not clearly observed under this condition due to the existence of a long M-N-O equilibrium.

Photoinduced proton release in proteorhodopsin at low pH: the possibility of a decrease in the pK(a) of Asp227

Proteorhodopsin (PR) is one of the microbial rhodopsins that are found in marine eubacteria and likely functions as an outward light-driven proton pump. Previously, we [Tamogami, J., et al. (2009) Photochem. Photobiol.85, 578-589] reported the occurrence of a photoinduced proton transfer in PR between pH 5 and 10 using a transparent ITO (indium-tin oxide) or SnO(2) electrode that works as a time-resolving pH electrode. In the study presented here, the proton transfer at low pH (<4) was investigated. Under these conditions, Asp97, the primary counterion to the protonated Schiff base, is protonated. We observed a first proton release that was followed by an uptake; during this process, however, the M intermediate did not form. Through the use of experiments with several PR mutants, we found that Asp227 played an essential role in proton release. This residue corresponds to the Asp212 residue of bacteriorhodopsin, the so-called secondary Schiff base counterion. We estimated the pK(a) of this residue in both the dark and the proton-releasing photoproduct to be ~3.0 and ~2.3, respectively. The pK(a) value of Asp227 in the dark was also estimated spectroscopically and was approximately equal to that determined with the ITO experiments, which may imply the possibility of the release of a proton from Asp227. In the absence of Cl(-), we observed the proton release in D227N and found that Asp97, the primary counterion, played a key role. It is inferred that the negative charge is required to stabilize the photoproducts through the deprotonation of Asp227 (first choice), the binding of Cl(-) (second choice), or the deprotonation of Asp97. The photoinduced proton release (possibly by the decrease in the pK(a) of the secondary counterion) in acidic media was also observed in other microbial rhodopsins with the exception of the Anabaena sensory rhodopsin, which lacks the dissociable residue at the position of Asp212 of BR or Asp227 of PR and halorhodopsin. The implication of this pK(a) decrease is discussed.

Histochemical analyses of anti-microbial substances in canine perianal skin with special reference to glandular structures

Circumanal glands are prominent features of the canine perianal skin, which are often located near to the sebaceous glands and apocrine glands. As the functional relevance of circumanal glands is yet unknown, we studied the localisation of sialic acids and anti-microbial substances (lysozyme, immunoglobulin A, lactoferrin, β-defensin) in these glandular structures by lectin histochemistry and immunohistochemistry. The glands exhibited a number of sialic acids that were linked to α2-6Gal/GalNAc and α2-3Galβ1-4GlcNAc. Additionally, lysozyme, lactoferrin and β-defensin could be demonstrated in the three types of skin glands, whereas IgA was only detectable in the apocrine glands. The results of the study suggest the specific significance of the circumanal glands. Independent of a certain endocrine role, their products may mainly function as protective agents to preserve the integrity of the anal region, considering that sialic acids and anti-microbial substances are important in defence mechanisms.

Photo-induced bleaching of sensory rhodopsin II (phoborhodopsin) from Halobacterium salinarum by hydroxylamine: identification of the responsible intermediates

Sensory rhodopsin II from Halobacterium salinarum (HsSRII) is a retinal protein in which retinal binds to a specific lysine residue through a Schiff base. Here, we investigated the photobleaching of HsSRII in the presence of hydroxylamine. For identification of intermediate(s) attacked by hydroxylamine, we employed the flash-induced bleaching method. In order to change the concentration of intermediates, such as M- and O-intermediates, experiments were performed under varying flashlight intensities and concentrations of azide that accelerated only the M-decay. We found the proportional relationship between the bleaching rate and area under the concentration-time curve of M, indicating a preferential attack of hydroxylamine on M. Since hydroxylamine is a water-soluble reagent, we hypothesize that for M, hydrophilicity or water-accessibility increases specifically in the moiety of Schiff base. Thus, hydroxylamine bleaching rates may be an indication of conformational changes near the Schiff base. We also considered the possibility that azide may induce a small conformational change around the Schiff base. We compared the hydroxylamine susceptibility between HsSRII and NpSRII (SRII from Natronomonas pharaonis) and found that the M of HsSRII is about three times more susceptible than that of the stable NpSRII. In addition, long illumination to HsSRII easily produced M-like photoproduct, P370. We thus infer that the instability of HsSRII under illumination may be related to this increase of hydrophilicity at M and P370.

Prevalence of Schistosoma intercalatum and S. haematobium Infection among Primary Schoolchildren in Capital Areas of Democratic Republic Of São Tomé and Príncipe, West Africa

BACKGROUND

A parasitological survey of Schistosoma haematobium and S. intercalatum infection among primary schoolchildren in capital area of Democratic Republic of São Tomé and Príncipe (DRSTP) was undertaken.

METHODS

Subjects with positive infection were confirmed by the detection of S. haematobium ova in the urine or S. intercalatum ova in the stool by using centrifugation concentration or merthiolate-iodine-formalin concentration method. Totally, 252 urine and stool samples, respectively, were obtained from apparently healthy schoolchildren, of which 121 from boys (9.8 ± 1.4 yr) and 131 from girls (9.7 ± 1.3 yr).

RESULTS

None of participating schoolchildren were found having S. haematobium ova in the urinary specimen. While, among 4 primary schools studied, only schoolchildren from Saint Marçal were detected with S. intercalatum ova in the fecal specimen, making the overall prevalence of S. intercalatum infection among schoolchildren was 2.4% (6/252) and girls had insignificantly higher prevalence (3.1%, 4/131) than that (1.7%, 2/121) in boys (χ(2) = 0.5, P = 0.5).

CONCLUSION

Water control and sanitation as well as snails eliminated by molluscicides are urgently needed to reduce S. intercalatum infection in DRSTP inhabitants.

Ligand specificity determined by differentially arranged common ligand-binding residues in bacterial amino acid chemoreceptors Tsr and Tar

Escherichia coli has closely related amino acid chemoreceptors with distinct ligand specificity, Tar for l-aspartate and Tsr for l-serine. Crystallography of the ligand-binding domain of Tar identified the residues interacting with aspartate, most of which are conserved in Tsr. However, swapping of the nonconserved residues between Tsr and Tar did not change ligand specificity. Analyses with chimeric receptors led us to hypothesize that distinct three-dimensional arrangements of the conserved ligand-binding residues are responsible for ligand specificity. To test this hypothesis, the structures of the apo- and serine-binding forms of the ligand-binding domain of Tsr were determined at 1.95 and 2.5 Å resolutions, respectively. Some of the Tsr residues are arranged differently from the corresponding aspartate-binding residues of Tar to form a high affinity serine-binding pocket. The ligand-binding pocket of Tsr was surrounded by negatively charged residues, which presumably exclude negatively charged aspartate molecules. We propose that all these Tsr- and Tar-specific features contribute to specific recognition of serine and aspartate with the arrangement of the side chain of residue 68 (Asn in Tsr and Ser in Tar) being the most critical.

Histochemical properties of sialic acids and antimicrobial substances in canine anal glands

The functional properties of sialic acids appear to be manifold. Additionally, antimicrobial substances serve as a non-specific defense against microorganisms. In this study, therefore, the localization of sialic acids and antimicrobial substances in the anal glands of dog was studied by sialoglycoconjugate histochemistry and immunohistochemistry. The secretory epithelium, luminal secretions and excretory ducts exhibited high levels of sialoglycoconjugates that terminated in Siaα2-6Gal/GalNAc or Siaα2-3Gal1-4GlcNAc. Additionally, O-acetylated sialic acids were detectable in these glandular structures. Antimicrobial substances, such as lysozyme, immunoglobulin A (IgA), lactoferrin and the peptide group of β-defensins, were also demonstrated as products of the anal glands. The results obtained are discussed with regard to the functional significance of the anal glands. These secretory products may create a defensive barrier against microbial invasion at the anal mucosa.

Stability study of all-permanent-magnet electron cyclotron resonance ion source

Beam intensity fluctuation was investigated using an electron cyclotron resonance ion source of an all-permanent-magnet type under development for highly stable beam intensity. While the source achieved a stability of better than 3.2% by strict regulation of the coolant temperature change within +/-0.1 degrees C, the intensity varies strongly with intentional changes in the temperature of the plasma chamber coolant. The influence of the temperature on chamber expansion, magnetic field strength, and vacuum was measured or estimated in detail. The result shows that a slight change in vacuum and magnetic field strength has considerable influence on the intensity fluctuation.

Anti-parallel membrane topology of a homo-dimeric multidrug transporter, EmrE

EmrE in Escherichia coli belongs to the small multidrug resistance (SMR) transporter family. It functions as a homo-dimer, but the orientation of the two monomers in the membrane (membrane topology) is under debate. We expressed various single-cysteine EmrE mutants in E. coli cells lacking a major efflux transporter. Efflux from cells expressing the P55C or T56C mutant was blocked by the external application of membrane-impermeable SH-reagents. This is difficult to explain by the parallel topology configuration, because Pro55 and Thr56 are considered to be located in the cytoplasm. From both the periplasm and the cytoplasm, biotin-PE-maleimide, a bulky membrane-impermeable SH-reagent, could access the cysteine residue at the 25th position in the presence of transport substrates and at the 108th position. These observations support the anti-parallel topology in the membrane.

Constitutive activity in chimeras and deletions localize sensory rhodopsin II/HtrII signal relay to the membrane-inserted domain

Halobacterium salinarum sensory rhodopsin II (HsSRII) is a phototaxis receptor for blue-light avoidance that relays signals to its tightly bound transducer HsHtrII (H. salinarum haloarchaeal transducer for SRII). We found that disruption of the salt bridge between the protonated Schiff base of the receptor's retinylidene chromophore and its counterion Asp73 by residue substitutions D73A, N or Q constitutively activates HsSRII, whereas the corresponding Asp75 counterion substitutions do not constitutively activate Natronomonas pharaonis SRII (NpSRII) when complexed with N. pharaonis haloarchaeal transducer for SRII (NpHtrII). However, NpSRII(D75Q) in complex with HsHtrII is fully constitutively active, showing that transducer sensitivity to the receptor signal contributes to the phenotype. The swimming behaviour of cells expressing chimeras exchanging portions of the two homologous transducers localizes their differing sensitivities to the HtrII transmembrane domains. Furthermore, deletion constructs show that the known contact region in the cytoplasmic domain of the NpSRII-NpHtrII complex is not required for phototaxis, excluding the domain as a site for signal transmission. These results distinguish between the prevailing models for SRII-HtrII signal relay, strongly supporting the 'steric trigger-transmembrane relay model', which proposes that retinal isomerization directly signals HtrII through the mid-membrane SRII-HtrII interface, and refuting alternative models that propose signal relay in the cytoplasmic membrane-proximal domain.

Anti-parallel membrane topology of two components of EbrAB, a multidrug transporter

EbrAB is a multidrug-resistance transporter in Bacillus subtilis that belongs to the small multidrug resistance, and requires two polypeptides of both EbrA and EbrB, implying that it functions in the hetero-dimeric state. In this study, we investigated the transmembrane topologies of EbrA and EbrB. Various single-cysteine mutants were expressed in Escherichia coli cells, and the efflux activity was measured. Only mutants having a high activity were used for the topology experiments. The reactivity of a membrane impermeable NEM-fluorescein against the single cysteine of these fully functional mutants was examined when this reactive fluorophore was applied either from the outside or both sides of the cell membrane or in the denatured state. The results clearly showed that EbrA and EbrB have the opposite orientation within the membrane or an anti-parallel configuration.

Effect of serotonin on the differentiation of human monocytes into dendritic cells

The local cytokine environment and presence of stimulatory signals determine whether monocytes acquire dendritic cell (DC) or macrophage characteristics and functions. Because enhanced platelet activation is reported in patients with many allergic disorders, such as atopic dermatitis, platelet-derived factors may influence monocytic differentiation into DC. In this study we examined the effect of serotonin, a prototypic mediator of allergic inflammation released mainly by activated platelets at the inflammatory site, on the granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4-driven differentiation of monocytes into monocyte-derived DC. Monocytes from healthy adult donors were cultured with GM-CSF and IL-4 in the presence or absence of serotonin, and the phenotypes and function of these cells were analysed. In the presence of serotonin, monocytes differentiated into DC with reduced expression of co-stimulatory molecules and CD1a, whereas expression of CD14 was increased. These serotonin-treated DC exhibited significantly reduced stimulatory activity toward allogeneic T cells. However, these cells showed enhanced cytokine-producing capacity, including IL-10 but not IL-12. There was no significant difference between both types of DC in phagocytic activity. Experiments using agonists and antagonists indicated that serotonin 5-hydroxytryptamine (5-HT) induced the alteration of their phenotype and reduction in antigen-presenting capacity were mediated via 5-HTR(1/7). It is therefore suggested that serotonin-driven DC may have a regulatory function in the inflammatory process.

Cytochemical Localization of Glycoconjugates in the Secretory Epithelial Cells Lining the Prostate Gland of the Miniature Pig

The aim of the study was to emphasize several specific functional aspects of the mammalian prostate gland. In this connection, the subcellular localization and characterization of glycoconjugates in the secretory epithelial cells were examined that line the prostate gland of the miniature pig, using cytochemistry, including lectin-gold methods. The results verified a diversified pattern of glycoconjugates in the structures of the secretory cells. The secretory granules and the free surface coat of the plasma membrane contained several sugar moieties such as alpha-D-Man, alpha-D-Glc, alpha-L-Fuc, beta-D-Gal, GalNAc, GlcNAc and NeuAc (sialic acid), whereas the Golgi apparatus exhibited GlcNAc and sialic acid residues. In addition, the cisterns of the endoplasmic reticulum showed alpha-D-Man and alpha-D-Glc moieties. It seems likely that the secretory glycoconjugates demonstrated contribute to favourable conditions for fertilization.

Two-component bacterial multidrug transporter, EbrAB: Mutations making each component solely functional

EbrAB in Bacillus subtilis belongs to a novel small multidrug resistance (SMR) family of multidrug efflux pumps. EmrE in Escherichia coli, a representative of SMR, functions as a homo-oligomer in the membrane. On the other hand, EbrAB requires a hetero-oligomeric configuration consisting of two polypeptides, EbrA and EbrB. Although both polypeptides have a high sequence similarity, expression of either single polypeptide does not confer the multidrug-resistance. We performed mutation studies on EbrA and B to determine why EbrAB requires the hetero-oligomerization. Mutants of EbrA and B lacking both the hydrophilic loops and the C-terminus regions conferred the multidrug-resistance solely by each protein. This suggests that the hydrophilic loops and the C-terminus regions constrain them to their respective conformations upon the formation of the functional hetero-oligomer.

Morphological, histochemical and immunohistochemical characterization of secretory production of the ciliary glands in the porcine eyelid

In addition to performing general histology and cytology of the ciliary glands of the miniature pig, we studied the localization of glycoconjugates and beta-defensins in these glands with the use of carbohydrate histochemical and immunohistochemical methods. The secretory cells of the glands were equipped with non-homogeneous secretory granules, a well-developed Golgi apparatus and rough endoplasmic reticulum. The secretory epithelium and luminal secretion of the glands contained large amounts of neutral and acidic glycoconjugates with various saccharide residues (alpha-L-Fuc, beta-D-Gal, alpha-D-GalNAc and sialic acid). The sebaceous glands and tarsal glands also exhibited positive reactions to most of the histochemical methods. Additionally, the antimicrobial peptide group of beta-defensins was demonstrated to be products of the ciliary glands, as well as the sebaceous glands and tarsal glands. The results obtained are discussed with regard to the specific function of the ciliary glandular secretions. These secretory products may be related to the moistening and general protection of the skin surface of the eyelid and ocular surface.

A light-driven proton pump from Haloterrigena turkmenica: Functional expression in Escherichia coli membrane and coupling with a H+ co-transporter

A gene encoding putative retinal protein was cloned from Haloterrigena turkmenica (JCM9743). The deduced amino acid sequence was most closely related to that of deltarhodopsin, which functions as a light-driven H+ pump and was identified in a novel strain Haloterrigena sp. arg-4 (K. Ihara, T. Uemura, I. Katagiri, T. Kitajima-Ihara, Y. Sugiyama, Y. Kimura, Y. Mukohata, Evolution of the archaeal rhodopsins: Evolution rate changes by gene duplication and functional differentiation, J. Mol. Biol. 285 (1999) 163-174. GenBank Accession No. AB009620). Thus, we called the present protein H. turkmenica deltarhodopsin (HtdR) in this report. Differing from the Halobacterium salinarum bacteriorhodopsin (bR), functional expression of HtdR was achieved in Escherichia coli membrane with a high yield of 10-15 mg protein/L culture. The photocycle of purified HtdR was similar to that of bR. The photo-induced electrogenic proton pumping activity of HtdR was verified. We co-expressed both HtdR and EmrE, a proton-coupled multi-drug efflux transporter in E. coli, and the cells successfully extruded ethidium, a substrate of EmrE, on illumination.

Measurement of electric current evoked by substrate transport via bi-directional H+/oligopeptide transporter over-expressed in HeLa cells: Electrogenic efflux and existence of a newly observed channel-like state

In the present study, we measured an electric current induced by substrate transport in a HeLa cell over-expressing a human intestinal di/tri-peptide transporter using the whole-cell patch-clamp technique. Gly-Sar, a typical substrate, induced an inward current associated with its uptake, which showed concentration-dependency following Michaelis-Menten-type kinetics with an apparent K(0.5) of 1.3mM as well as voltage-dependency. An outward current accompanying the efflux of Gly-Sar was also observed after washing out the cell. This outward current was voltage-dependent and was reduced by the inward proton gradient. In the case of hydrophobic dipeptides such as Gly-Phe and Gly-Leu, a distinctive current was observed: after washing out the cells, no outward current was observed, but rather, an 'inward leak' current was sustained in spite of the absence of transportable substrate. This leaky current was abolished by the perfusion of Gly-Sar and subsequent washing. It is considered that the hydrophobic substrate sticks within the substrate-binding site and causes the newly observed state, or the 'inward leak' current.

The Extracellular pH Dependency of Transport Activity by Human Oligopeptide Transporter 1 (hPEPT1) Expressed Stably in Chinese Hamster Ovary (CHO) Cells: A Reason for the Bell-Shaped Activity versus pH

Human oligopeptide transporter (hPEPT1) translocates di/tri-peptide by coupling to movement of proton down the electrochemical gradient. This transporter has the characteristics that the pH-profile of neutral dipeptide transport shows a bell-shaped curve with an optimal pH of 5.5. In the present study, we examined the reason for the decrease in the acidic region with hPEPT1-transfected CHO cells stably oeverexpressing hPEPT1 (CHO/hPEPT1). The pH profile of the transport activity vs. pH was measured in the presence of nigericin/monensin. Under this condition, the inwardly directed proton concentration gradient was dissipated while the membrane potential remained. As pH increased the activity increased, and the Henderson-Hasselbalch equation with a single pKa was fitted well to the activity curve. The pKa value was estimated to be 6.7+/-0.2. This value strongly suggests that there is a key amino acid residue, which is involved in pH regulation of transport activity. To identify the key amino acid residue, we examined the effects of various chemical modifications on pH-profile of the transport activity. Modification of carboxyl groups or hydroxyl groups had no significant influence on the pH-profile, whereas a chemical modification of histidine residue with diethylpyrocarbonate (DEPC) completely abolished the transport activity in CHO/hPEPT1 cells. On the other hand, this abolishment was almost prevented by the presence of 10 mM Gly-Sar. This protection was observed only in the presence of the substrate of hPEPT1, indicating that the histidine residue is located at the substrate recognition site. The pH-profile of the transport activity in CHO/hPEPT1 cells treated with DEPC in the presence of 10 mM Gly-Sar also showed a bell-shape similar to that in non-treated CHO/hPEPT1 cells. These data stressed that the histidine residue located at or near the substrate binding site is involved in the pH regulation of transport activity.

The elution profile of immobilized liposome chromatography: determination of association and dissociation rate constants

The interaction of lipophilic cations, tetraphenylphosphonium and triphenylphosphonium homologues with liposomes was investigated using immobilized liposome chromatography (ILC). Large unilamellar liposomes with a mean diameter of 100 nm were stably immobilized in chromatographic gel beads by avidin-biotin. The distribution coefficient calculated from (Ve-V0)/Vs (Ve, retention volume; V0, the void volume; Vs, the stationary phase volume) was found to be independent of flow rate, injection amount and gel bed volume, which is consistent with chromatograph theory. The relationship between the bandwidth and solvent flow rate did not follow band-broadening theories reported thus far. We hypothesized that the solvent might be forced to produce large eddies, spirals or turbulent flow due to the presence of liposomes fixed in the gel. Therefore, we developed a new theory for ILC elution: The column is composed of a number of thin disks containing liposomes and solution, and within each disk the solution is well mixed. This theory accounts for our results, and we were able to use it to estimate the rate constants of association and dissociation of the phosphonium to/from liposomes.

Glycoconjugate histochemistry of the seminal vesicles of the Japanese miniature (Shiba) goat

The present study localizes and characterizes complex glycoconjugates in the seminal vesicles of the Japanese Shiba goat, using several carbohydrate histochemical procedures, including lectin techniques at light and electron microscopic levels. Glandular epithelial cells and luminal secretions were shown to contain neutral and acidic glycoconjugates with various saccharide residues, such as alpha-D-Man, alpha-D-Glc, alpha-L-Fuc, beta-D-Gal, GalNAc, GlcNAc, and NeuAc (sialic acid). The terminal oligosaccharide chains of sialoglycoconjugates present in the seminal vesicles were NeuAc alpha 2-3Gal beta 1-3GalNAc and NeuAc alpha 2-3Gal beta 1-4GlcNAc. In addition, in lysosomes of the glandular epithelial cells alpha-D-Man, alpha-D-Glc, GlcNAc and NeuAc (sialic acid) residues could be detected, the secretory vesicles contained alpha-L-Fuc, and the endoplasmic reticulum exhibited alpha-D-Man and alpha-D-Glc residues. The complex glycoconjugates with various sugar residues found in the seminal vesicles of the goat may be involved in various fertilization-related events.

Granulocyte colony-stimulating factor-producing cutaneous angiosarcoma with leukaemoid reaction arising on a burn scar

We report a 46-year-old man with a giant tumour in a burn scar on his buttock. Pathological examination revealed that the dermis was filled with anastomosing vascular channels and round- or spindle-type atypical cells, which were compatible with the diagnosis of cutaneous angiosarcoma. Based on prominent leucocytosis (up to 113 000 microL-1), we measured serum granulocyte colony-stimulating factor (G-CSF). The highly elevated serum G-CSF of 303 ng L-1 (normal, 6.1-21.5 ng L-1) and positive immunohistochemical staining of the tumour tissue for G-CSF indicated that G-CSF was produced by the cutaneous angiosarcoma. To our knowledge, this is the first reported case of G-CSF-producing cutaneous angiosarcoma.

Strand exchange reaction in vitro and DNA-dependent ATPase activity of recombinant LIM15/DMC1 and RAD51 proteins from Coprinus cinereus

We previously cloned recA-homolog genes from a basidiomycete, Coprinus cinereus, and obtained the recombinant proteins (Nara et al., Mol. Gen. Genet. 262, 781-789, 1999, see Ref. 1; Nara and Sakaguchi, Biochem. Biophys. Res. Commun. 275, 97-102, 2000, see Ref. 2). The primary purpose of the present study was to characterize the biochemical properties of the recombinant LIM15/DMC1 (CoLIM15) and RAD51 (CoRAD51) proteins. We purified the recombinant proteins, and their molecular masses were 37 and 35 kDa, respectively. Both enzymes showed DNA-dependent ATPase activity and ATP-dependent strand exchange reaction in vitro. CoRad51 was a five- to sixfold stronger DNA-dependent ATPase and showed greater dependency on single-stranded DNA than CoLim15. In meiosis, both enzymes were highly accumulated in the meiotic tissue at leptotene and zygotene stages at which the homologous chromosomes pair, but disappeared just before the pachytene stage at which they recombine. From these and the previously reported results, we discuss here the relationships between the enzymes and meiosis.

A rat model of postthoracotomy pain: behavioural and spinal cord NK-1 receptor assessment

PURPOSE

To develop a new rat model of postthoracotomy pain for investigating its mechanisms and clarifying neurochemical changes.

METHODS

Male Wistar rats were randomly assigned to three groups that underwent either fourth and fifth intercostal nerve ligation, cutting of the fourth and fifth ribs, or a sham operation in which only pleura was cut. For behavioural response assessment during the following month, pinch and touch were used as mechanical stimuli, and acetone was used as a cold thermal stimulus. In addition, (125)I-substance P autoradiography was used to determine neurokinin (NK) receptor density in spinal cord laminae I and II at one to six weeks after surgery.

RESULTS

In rats with nerve ligation, hypersensitivity to noxious and non-noxious stimuli continued throughout the month. The "mirror phenomenon" was observed. The lowest threshold was obtained in the dorsomedial portion of the T4 dermatome on the side of surgery. In rats with rib cutting, a lowered threshold to noxious and non-noxious stimuli was observed for two weeks. In rats with sham operations, hypersensitivity was seen only at postoperative day one. NK-1 receptor density on the side of operation increased significantly in rats with nerve ligation from day seven to 28. Receptor density was highest on day 14 (22.97 +/- 1.04 fmol x mg(-1) tissue vs. control, 16.22 +/- 0.43), representing a 50% receptor excess on the side of ligation compared to the contralateral side.

CONCLUSION

Intercostal nerve damage induces long-term postthoracotomy pain and an increase of spinal NK-1 receptors in rats. This model may be useful for investigation of postthoracotomy pain.

Perioperative management of biventricular failure after closure of a long-standing massive arteriovenous fistula

PURPOSE

To report the perioperative management of arteriovenous fistula (AVF) closure in a patient with high-output heart failure and pulmonary hypertension.

CLINICAL FEATURES

In a 71-yr-old man, closure of a long-standing massive AVF between the right femoral artery and vein was performed. After closure of the AVF, his pulmonary artery pressure (PAP) increased from 52/21 mmHg to 68/26 mmHg, his cardiac index decreased from 5.27 L.min(-1).m(-2) to 3.18 L.min(-1).m(-2), and his pulmonary wedge pressure increased from 15 mmHg to 32 mmHg due to an acute increase in afterload. Co-administration of prostaglandin E and a phosphodiesterase III inhibitor improved the cardiac index and the PAP.

CONCLUSIONS

Surgical closure of the fistula may not always lead to resolution of the high output cardiac failure. In this case, afterload management using arterial dilators (prostaglandin E1, phosphodiesterase III inhibitor), use of inotropic drugs (phosphodiesterase III inhibitor), and close attention to volume status was crucial for a successful outcome after surgical AVF closure.

Protective immunity to Schistosoma japonicum infection depends on the balance of T helper cytokine responses in mice vaccinated with gamma-irradiated cercariae

Although the strain difference in protection of mice to Schistosoma mansoni infection has been described, limited information is available in the case of Schistosoma japonicum. In the present study, we compared the protective immunity to S. japonicum infection and cytokine production in various strains of mice vaccinated with gamma-irradiated cercariae. A significant reduction in worm recovery was observed in male and female mice of DBA/2 at a 6-week interval between vaccination and a challenge infection, whereas vaccinated mice of C57BL/6, C57BL/10, (C57BL/6 x DBA/2) F1 (B6D2F1) and (C57BL/10 x DBA/2) F1 (B10D2F1) showed no detectable level of protection. No sex-linked difference in development of resistance was observed in any of the strains so far examined. Vaccination with gamma-irradiated cercariae twice with a 3-week interval also induced significant protection against a challenge infection in DBA/2 but not in BALB/c or C57BL/6 strains. Further studies demonstrated that spleen cells of vaccinated C57BL/6 mice produced lower levels of IFN-gamma compared to the cells of vaccinated BALB/c and DBA/2. On the other hand, production of IL-10 by spleen cells was relatively higher in BALB/c mice than in the other two strains. Macrophages that had been stimulated with spleen cell culture supernatants derived from vaccinated DBA/2 damaged schistosomula more effectively than cells stimulated with supernatants derived from the other strains. These results suggest that different levels of protection observed among strains of mice depend on the balance of cytokine responses which consequently activate or suppress macrophage-mediated damage to schistosomula.

Long descending lymphatic pathway from the pancreaticoduodenal region to the para-aortic nodes: its laterality and topographical relationship with the celiac plexus

In 6 of 15 postmortem-treated cadaveric specimens, we found macroscopically thick lymphatic collecting vessels that originated from not only the nodes along the common hepatic artery (No. 8 nodes) but also from the pancreaticoduodenal region, and which drained directly into the para-aortic nodes immediately below the left renal vein (No. 16b1-inter or -latero nodes). The collecting vessels, if they originated from the ventral (dorsal) visceral side, passed to the left (right) of the superior mesenteric and celiac arteries. Moreover, the right-side vessels (5 specimens) were classified into superficial and deep courses to the celiac plexus, whereas they were superficial in the left side (2 specimens). One of the deep (right) courses continued to the thoracic duct without any intercalated nodes. In addition, another deep route drained into the para-aortic node immediately above the left renal vein (No. 16a2-inter node). We consider that these collecting vessels form "direct descending pathways" from the relatively peripheral lymphatics in the upper abdomen toward the thoracic duct origin. The pathway seems to be a collateral, or even major drainage route, and it appears responsible for skipped metastasis of primary cancer. Since the classical, limited entity of the intestinal lymph trunk does not coincide with our pathway, it should be reconsidered. The proposed entity of the direct, long descending pathway will influence the selection and modification of lymphadenectomy methods in cancer surgery in the pancreaticoduodenal region.

[A case of multiple sclerosis with recurrent episodes of psychiatric symptoms]

We reported a 19-year-old woman with multiple sclerosis (MS) with recurrent episodes of psychiatric symptoms at the age of 10 and 19, as the first and 11th relapse, respectively. Her first episode of MS resembled acute encephalitis at the age of 9 and she relapsed 12 times. The psychiatric symptoms were not mood disorders but altered states of consciousness, such as the delirous state. She was treated with high doses of intravenous methylpredonisolone and her symptoms were almost resolved, but her anxiety neurosis remained. Her MRI showed demyelination in the white matter of the frontal lobe and the hippocampus, which suggested that psychiatric symptoms of MS would be related to the frontal lobe lesion.

A glass capillary ultramicroelectrode with an electrokinetic sampling ability

A glass capillary ultramicroelectrode (tip diameter approximately 1.2 microm) having an electrokinetic sampling ability is described. It is composed of a pulled glass capillary filled with an inner solution and three internal electrodes (Pt working and counter electrodes and an Ag/AgCl reference electrode). The voltammetric response of the capillary electrode is based on electrokinetic transport of analyte ions from the sample solution into the inner solution across the conical tip. It was found that the electrophoretic migration of analytes at the conical tip is faster than electroosmotic flow, enabling electrokinetic transport of analyte ions into the inner solution of the electrode. By using [Fe(CN)6]4- and (ferrocenylmethyl)trimethylammonium (FcTMA+) ions as model analytes, differential pulse voltammetric responses of the capillary electrode were investigated in terms of tip diameter of the capillary, sampling voltage, sampling time, detection limit and selectivity. The magnitude of the response depends on the size and charge of analyte ions. With a capillary electrode having a approximately 1.2-microm tip diameter, which minimizes non-selective diffusional entry of analytes, the response after 1 h sampling at +1.7 V is linearly related to [Fe(CN)6]4- concentration in the range of 0.50-5.0 mM with the detection limit of 30 microM. Application of a potential of the same sign as that of the analyte ion forces the analyte to move out from the electrode to the solution, enabling reuse of the same capillary electrode. The charge-selective detection of analytes with the capillary electrode is demonstrated for [Fe(CN)6]4- in the presence of FcTMA+.

The comparative effects of propofol versus thiopental on middle cerebral artery blood flow velocity during electroconvulsive therapy

Electroconvulsive therapy provokes abrupt changes in both systemic and cerebral hemodynamics. An anesthetic that has a minor effect on cerebral hemodynamics might be more suitable for patients with intracranial complications, such as cerebral aneurysm. The purpose of our present study was to compare the effects of thiopental and propofol on cerebral blood flow velocity. We continuously compared cerebral blood flow velocity at the middle cerebral artery (MCA) during electroconvulsive therapy, using propofol (1 mg/kg, n = 20) versus thiopental (2 mg/kg, n = 20) anesthesia. Systemic hemodynamic variables and flow velocity at the MCA were measured until 10 min after the electrical shock. Heart rate and arterial blood pressure increased in the thiopental group until 5 min after the electrical shock. In the propofol group, an increase in mean blood pressure was observed to 1 min after the electrical shock. Mean flow velocity at the MCA decreased after anesthesia in both groups, and increased at 0.5-3 min after the electrical shock in the thiopental group and at 0.5 and 1 min after the shock in the propofol group. The flow velocities at 0.5-5 min after the electrical shock were significantly more rapid in the thiopental group compared with the propofol group. ¿abs¿

IMPLICATIONS

Cerebral blood flow velocity change, measured by transcranial Doppler sonography during electroconvulsive therapy, was minor using propofol anesthesia compared with barbiturate anesthesia. Propofol anesthesia may be suitable for patients who cannot tolerate abrupt cerebral hemodynamic change.

Evolutionary implications of the mosaic pyrimidine-biosynthetic pathway in eukaryotes

The de-novo pyrimidine biosynthetic pathway involves six enzymes, in order from the first to the sixth step, carbamoyl-phosphate synthetase II (CPS II) comprising glutamine amidotransferase (GAT) and carbamoyl-phosphate synthetase (CPS) domains or subunits, aspartate carbamoyltransferase (ACT), dihydroorotase (DHO), dihydroorotate dehydrogenase (DHOD), orotate phosphoribosyltransferase (OPRT), and orotidine-5'-monophosphate decarboxylase (OMPDC). In contrast with reports on molecular evolution of the individual enzymes, we attempted to draw an evolutionary picture of the whole pathway using the protein phylogeny. We demonstrate highly mosaic organizations of the pyrimidine biosynthetic pathway in eukaryotes. During evolution of the eukaryotic pathway, plants and fungi (or their ancestors) in particular may have secondarily acquired the characteristic enzymes. This is consistent with the fact that the organization of plant enzymes is highly chimeric: (1) two subunits of CPS II, GAT and CPS, cluster with a clade including cyanobacteria and red algal chloroplasts, (2) ACT not with a cyanobacterium, Synechocystis spp., irrespective of its putative signal sequence targeting into chloroplasts, and (3) DHO with a clade of proteobacteria. In fungi, DHO and OPRT cluster respectively with the corresponding proteobacterial counterparts. The phylogenetic analyses of DHOD and OMPDC also support the implications of the mosaic pyrimidine biosynthetic pathway in eukaryotes. The potential importance of the horizontal gene transfer(s) and endosymbiosis in establishing the mosaic pathway is discussed.