HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY OF PHYTOPLANKTON PIGMENTS USING A POLYMERIC REVERSED-PHASE C18 COLUMN1

A high-performance liquid chromatographic (HPLC) method is described that allows improved resolution of several chemotaxonomically significant phytoplankton pigments. The protocol, which employs two pumps and a modified Mantoura and Llewellyn (1983) solvent system, can be easily adapted for many HPLC systems currently in use. The most unique aspect of the method is the use of a polymeric C₁₈ reversed phase HPLC column (VYDAC 201TP). In comparison to the monomeric C₁₈ columns typically used in the characterization of phytoplankton pigments, polymeric C₁₈ columns offer superior selectivity for structurally similar compounds. The protocol was evaluated for the ability to resolve most of the phytoplankton pigments of diagnostic importance using algal cultures from nine classes. Pigment pairs that were resolved by the method include a) lutein and zeaxanthin, b) neoxanthin and 19′-hexanoyloxyfucoxanthin, and c) α-carotene and β-carotene, and partial resolution of chlorophyll c₁ and chlorophyll c₂.     

Radiation-induced changes in oral carcinoma cells – a multiparametric evaluation

The aim of this study was to see whether serial cytological evaluation of various cellular abnormalities in tumours from patients receiving fractionated radiotherapy can predict radio-response in oral carcinoma. Cytological assessment was carried out in scrape smears collected prior to and during the course of radiotherapy in 68 patients with squamous cell carcinoma of the oral cavity planned for radical radiotherapy with accelerated fraction schedule. Smears were evaluated for a set of 15 radiation-induced cellular abnormalities. The relationship between the cellular alterations and the cumulative radiation dose was analysed by Kruskal-Wallis one-way anova. The results showed that among the various quantifiable changes that occur in irradiated cancer cells, karyolysis, karyorrhexis, pyknosis, cytolysis, multinucleation, micronucleation and nuclear budding show significant increase depending on the dose of radiation. The radio-resistant group of patients exhibited a lesser degree of change compared with the radio-sensitive group. This suggests that radio-resistance may be due to the defective induction of cell damage and that these cytological features may have potential use as predictive markers of radio-sensitivity in oral carcinoma.     

Design and applications of a self-aligning liquid junction-electrospray interface for capillary electrophoresis-mass spectrometry

A simple self-aligning liquid junction-electrospray interface for coupling a capillary electrophoresis (CE) system to an atmospheric pressure ionization (API) mass spectrometer (CE-MS) was developed. In contrast to previous liquid junction interfaces, the self-aligning liquid junction interface simplifies the precise alignment of the CE capillary and the sprayer needle and uses a positive make-up flow. Several capillary CE-MS applications were run using both the self-aligning liquid junction interface and the widely used sheath flow interface for comparison purposes. The electrospray stability of the self-aligning liquid junction interface is consistently better even when non-volatile electrolyte solutions are used. At first, some band broadening was obtained with the self-aligning liquid junction interface. Experiments with different CE buffer systems suggested that this band broadening was caused by the materials used in constructing the interface. By using a more inert material for the sprayer needle, the self-aligning liquid junction exhibits excellent electrophoretic resolution, comparable sensitivity, and higher signal-to-noise ratios when run under the same conditions as the sheath flow interface.     

Tachykinin NK-1 receptor probed with constrained analogues of substance P

The action of rotameric probes introduced either in position 7 or 8 in the sequence of substance P (SP) was investigated, i.e. -tetrahydroisoquinoleic acid (Tic), -fluorenylglycine (Flg), -diphenylalanine (Dip), the diastereoisomers of -1-indanylglycine (Ing) and -benz[ƒ]indanylglycine (Bfi), the Z- and E-isomers of dehydrophenylalanine and dehydronaphthylalanine (Δ^ZPhe, Δ^EPhe, Δ^ZNal, Δ^ENal) and (Dmp). The aim of this study was the topographical characterization of the binding subsites of human NK-1 receptor expressed in CHO cells, especially the S₇ and S₈ subsites, corresponding to residues Phe⁷ and Phe⁸ of substance P. According to the binding potencies of these substituted-SP analogues, the S₇ binding subsite is smaller than the S₈ subsite: the S₇ subsite accepts only one aromatic nucleus, while the S₈ can accommodate three coplanar nuclei altogether. These findings are compatible with the idea that the S₈ binding subsite may reside in the extracellular loops of the hNK-1 receptor. NK-1 agonists bind to human NK-1 receptor and activate the production of both inositol phosphates and cyclic AMP. As already quoted for septide, [pGlu⁶, Pro⁹]SP(6–11), discrepancies are observed between affinity (K_i) and activity (EC₅₀) values for IPs production. While a weak correlation between K_i and EC₅₀ values for IPs production could be found (r = 0.70), an excellent correlation could be demonstrated between their affinities (K_i) and their potencies (EC₅₀) for cAMP production (r = 0.97). The high potency (EC₅₀) observed for ‘septide-like’ molecules on PI hydrolysis, compared to their affinity is not an artefact related to the high level of NK-1 receptors expressed on CHO cells since a good correlation was found between EC₅₀ values obtained for PI hydrolysis and those measured for spasmogenic activity in guinea pig ileum bioassay (r = 0.94).

According to the binding potencies of constrained analogues of phenylalanine, the S₇ binding subsite of human NK-1 receptor is small, whereas the S₈, which can accommodate three coplanar nuclei, might probably reside in the extracellular loop. The discrepancies observed between affinity (K_i) and activity (EC₅₀) values for IPs production are not an artefact of CHO cells since a good correlation was found between EC₅₀ for PI hydrolysis and those measured in guinea pig ileum bioassay.     

毛细管水解及反相高效液相色谱分析蛋白质的氨基酸组成

 毛细管水解及反相高效液相色谱分析蛋白质的氨基酸组成陈平,梁宋平（湖南师范大学生物研究所,长沙４１０００６）氨基酸组成的分析是阐明蛋白质和多肽化学特性的基础,在蛋白质与多肽的氨基酸组成分析中,常采用对水解管反复充氮并抽真空的方法使蛋白质和多肽在隔绝氧气...     

Factors affectingin vitro establishment and shoot proliferation ofRosa hybrida L. andRosa Chinensis minima

Summary The effects of nodal explants collected at different plastochrones, use of various benzyladenine (BA) concentrations, sources of carbohydrates, and phases of the culture medium on shoot establishment and proliferation ofRosa hybrida L. andR. chinensis minima were evaluated. Higher numbers of shoots per explant were obtained fromR. hybrida cv. Carefree Beauty explants proximal to the apical meristem than those from distal nodes. However, proliferating shoots derived from plastochrones proximal to the apical meristem had a lower number of leaves/explant and were shorter than those derived from other distal plastochrones. Although shoot proliferation increased with higher BA concentration in the medium, a concentration of 4.4 μM BA was found optimum for axillary bud-break and shoot development forR. hybrida cvs. Adelaide Hoodless and Cuthert Grant. A higher shoot proliferation rate was observed forR. hybrida cv. Carefree Beauty explants grown on a medium containing 55.5 mM fructose than 58.4 mM sucrose. However, no differences were observed forR. hybrida cv. Cuthert Grant grown on a medium containing either fructose or sucrose. The mean number of shoots/explant was higher forR. chinensis minima cv. Red Sunblaze explants grown on a liquid (4.5) than on a solid medium (1.7) for the first reculture; while no significant differences between the two phases of the medium were observed for the second reculture. However, a higher mean number of shoots/explant was observed on solid-phase (4.0) than liquid-phase medium (3.4) for the third reculture. A higher mean number of leaves/shoot was obtained on a solidified medium rather than liquid medium in the first two consecutive recultures, while no differences were observed for the third reculture. Although a significant effect of BA concentration on mean number of shoots/explant was observed for Red Sunblaze nodal explants, the influence of BA concentration decreased in the two consecutive cultures for both phases of the medium. Hyperhydricity was observed on Red Sunblaze shoots grown on the liquid-phase medium.     

Detection of S-Phase Cells in Smear Cytology Using in Vitro Bromodeoxyuridine Labeling

A technique Is described for rapid detection of S-pha?e cells of tumor tissues in smear specimens using bromodeoxyuridine (BrdU) immunostaining. Mouse NR-S1 tumors and human tumor specimens were prepared for smear cytology after incubation in RPMI 1640 culture medium containing 200 μM BrdU at 37 °C under 3 atm for 1 hr. Samples were fixed in 70% ethanol for 30 min and used immediately or air dried for 30 min. Samples were then denatured in either 4 N HC1 or 0.07 N NaOH to prepare partially single-stranded DMA. Fixation with air drying for 30 min followed by 30 min in 70% ethanol and 1 min denaturation with 0.07 N NaOH resulted in satisfactory staining quality. Cultured tumor specimens were processed for routine paraffin sections after smears were made for cytology. The labeling indices of the smear specimens and of the paraffin sections gave similar results. This technique should be useful in evaluating the cell proliferative potential of tumor tissue in smear cytology without processing paraffin sections.     

人类口腔小生境微生物的多样性

本文论述了人类口腔中微生物的物种多样性,口腔小生境的复杂性与微生物多样性的关系,以及口腔中微生物变化与人类疾病和健康的关系。     

Distribution of various nickel compounds in rat organs after oral administration

In this study, eight kinds of nickel (Ni) compounds were orally administered to Wistar male rats and the distribution of each compound was investigated 24 h after the administration. The Ni compounds used in this experiment were nickel metal [Ni−M], nickel oxide (green) [NiO(G)], nickel oxide (black) [NiO(B)], nickel subsulfide [Ni₃S₂], nickel sulfide [NiS], nickel sulfate [NiSO₄], nickel chloride [NiCl₂], and nickel nitrate [Ni(NO₃)₂]. The solubilities of the nickel compounds in saline solution were in the following order; [Ni(NO₃)₂>NiCl₂>NiSO₄]≫[NiS>Ni₃S₂]>[NiO(B)>Ni−M>NiO(G)]. The Ni level in the visceral organs was higher in the rats given soluble Ni compounds; Ni(NO₃)₂, NiCl₂, NiSO₄, than that in the rats receiving other compounds. In the rats to which soluble Ni compounds were administered, 80–90% of the recovered Ni amounts in the examined organs was detected in the kidneys. On the other hand, the Ni concentration in organs administered scarcely soluble Ni compounds; NiO(B), NiO(G), and Ni−M were very low. The estimated absorbed fraction of each Ni compounds was increased with the increase of the solubility. These results suggest that the kinetic behavior of Ni compounds administered orally is closely related with the solubility of Ni compounds, and that the solubility of Ni compounds is one of the important factors for determining the health effect of Ni compounds.     

Oral administration of antigen does not influence the proliferation and IFN-γ production of responsive CD8+ T cells but enables to establish T cell clones with different lymphokine production profile.

Feeding of a whole casein diet, which abolished the α_s1-casein-specific proliferation and IFN-γ productivity of CD⁴⁺ T cells, did not affect the proliferative response of CD8⁺ T cells with regard to the antigen dose response, cell dose response, kinetics of the proliferation and epitope specificity, as well as IFN-γ production. To assess the characteristics of the CD8⁺ T cells, we established α_s1-casein-specific CD8⁺ T cell clones from both casein-fed and control mice. The established clones produced different amount of IFN-γ and IL-10, and one clone derived from the casein-fed mice produced a remarkable amount of IL-10. The clones from casein-fed mice produced considerable amounts of TGF-β, while those from control mice produced only small amounts. The possible role of CD8⁺ T cells in oral tolerance is discussed. This revised version was published online in June 2006 with corrections to the Cover Date.