GL331-induced disruption of cyclin B1/CDC 2 complex and inhibition of CDC 2 kinase activity

GL331, a new homologue of etoposide (VP-16), was developed to cope with the multiple drug resistance occurring in certain malignant tumours. We previously indicated that GL331, like VP-16 and other major cancer chemotherapeutic agents, induced apoptosis in a variety of human cancer cell lines including nasopharyngeal carcinoma (NPC) NPC-TW01 and NPC-TW04 cells. In this study, we further explored the effect of GL331 on the cell cycle progression of NPC cells. Flow cytometric analysis of DNA content was first used to demonstrate the ability of GL331 to induce cell growth arrest at S-G₂ phase in most NPC cells. Besides acting as a topoisomerase II inhibitor, GL331 inhibited cellular cyclin B1-associated CDC 2 kinase activity 6 h after treatment, accounting partly at least for its induction of the cell cycle arrest. As with cyclin A, D1, E, CDK 2 and PCNA, the levels of cyclin B1 and CDC 2 proteins were not changed after GL331 treatment; however, the ability to form complex between cyclin B1 and CDC 2 was obviously affected in GL331-treated NPC cells, which associates with the inhibition of cyclin B1/CDC 2 kinase activity elicited by GL331. These data could provide more principal bases for future therapeutic application of this potential anti-cancer agent.     

Direct somatic embryogenesis through thin cell layer culture in Panax ginseng

Direct somatic embryos were differentiated on cotyledon transverse Thin Cell Layers (tTCLs) of Panax ginseng after 9 weeks in the Murashige and Skoog basal (MS) medium containing 2,4-d (5M). When MS medium containing 2,4-d (5M) was used for seedling pretreatment and for tTCLs culture, somatic embryos were observed 2 weeks earlier, i.e. after 7 weeks of culture. On the tTCLs from seedlings pretreated with 2,4-d (5M) combined with benzyladenine and zeatin at 0.1 M (BZ), somatic embryos were observed after 6 weeks of culture and the percentage of embryogenesis was higher (62%) than when 2,4-d was used alone for pretreatment (40%). Similar results were also obtained from pretreatment with combinations of 2,4-d (5M) and thidiazuron (TDZ) (0.01, 0.1M). When a combination of 2,4-d (5M) and BZ (0.1M) was used both for seedling pretreatment and for tTCLs culture, both somatic embryos and shoots were observed after only 3 weeks. As the concentration of BZ increased, the percentage of somatic embryogenesis decreased but the percentage of organogenesis increased. Similar responses were obtained with a combination of 2,4-d (5M) and TDZ (0.01M). On the medium containing both NAA (0.3M) and BZ (1M), globular- and heart- stage embryos developed after 4 weeks of culture into cotyledonary-staged embryos which remained dormant after a short elongation of the embryo axis. The importance of seedling pretreatment by growth substances in enhancing somatic embryogenesis is reported.Abbreviations BA 6-benzyladenine - BZ combination of BA and zeatin - 2,4-d 2,4-dichlorophenoxyacetic acid - MS medium Murashige and Skoog basal medium - NAA a-naphthaleneacetic acid - TDZ thidiazuron - tTCLs transverse thin cell layers - TCL longitudinal thin cell layer     

In vitro comparison of ceftazidime,aztreonam, cefpirome,gentamicin, imipenem,enoxacin, and ticarcillin plus clavulanic acid against 108 strains ofPseudomonas maltophilia

Pseudomonas maltophilia is an uncommon cause of hospital-acquired infection and is resistant to most of the antimicrobial agents used in the treatment of gram-negative infections. Susceptibility of 108 isolates ofP. maltophilia to ceftazidime, aztreonam, defpirome, gentamicin, imipenem, enoxacin, and ticarcillin plus clavulanic acid was determined by an agar dilution method. The isolates were in general resistant to the antibiotics. Imipenem and cefpirome were not active at clinically achievable levels. Of the isolates, 20% were susceptible to 16 g/ml ceftazidime, 53% were susceptible to 4 g/ml enoxacin, 10% were susceptible to 4 g/ml gentamicin, and 25% were susceptible to 64 g/ml ticarcillin plus 2 g/ml clavulanic acid.     

Phenylacetic acid-induced somatic embryogenesis in cultured hypocotyl explants of geranium (Pelargonium x hortorum Bailey)

Summary The effect of a non-indole compound, phenylacetic acid (PAA), on the induction of somatic embryogenesis in tissue cultures of geranium (Pelargonium x hortorum Bailey cv. Scarlet Orbit Improved) was investigated. Hypocotyl explants derived from young, dark-grown seedlings were cultured on Murashige and Skoog (1962) medium (MS) supplemented with PAA or IAA (0.01–120 M) alone or in combination with BAP (8 M). Somatic embryogenesis was induced by both PAA and IAA at 0.01–20 M with 8 M BAP, however, the optima differed considerably for the two compounds. Maximal activity of IAA for somatic embryogenesis was found at 0.1–2.5 M, whereas PAA gave best results at 10 and 20 M under identical culture conditions. Higher concentrations (30–120 M) of IAA or PAA in the medium induced callusing in the explants, but the callus was neither embryogenic nor morphogenic.Abbreviations BAP N⁶-benzylaminopurine - IAA indole-3-acetic acid - MS Murashige and Skoog (1962) - PAA phenylacetic acid     

In vitro propagation of Asparagus maritimus – A rare Mediterranean salt-resistant species

Asparagus maritimus L. Miller is a rare species growing of the Mediterranean region and is morphologically similar to A. officinalis. In order to establish an efficient in vitro propagation protocol, explants were excised from spear segments and cultured on Murashige and Skoog (1962) medium containing 3% sucrose and various concentrations of growth regulators. The best shoot initiation (3–4 per explant) was achieved on a medium containing 0.88 M N⁶-benzyladenine (BA), 0.93 M kinetin, 1.07 M -naphthaleneacetic acid (NAA) and 3.90 M ancymidol. Shoot initiation could also be achieved without ancymidol but the shoots were thinner and longer. A very high shoot multiplication rate was achieved on media supplemented with 3% sucrose, 1.07 M NAA, 0.93 M kinetin, 0.44 M BA and various concentrations of ancymidol. The lowest concentration of ancymidol (0.39 M) significantly promoted the highest shoot multiplication rate (11.9 shoots/crown). For root formation, media were supplemented with 6% sucrose, 1.07 M NAA and various concentrations of ancymidol. Rooting frequency increased with higher ancymidol concentration up to 5.07 M (82.0% rooting). The number of ex vitro shoots formed was strongly correlated (r=0.66) with the length of roots formed in vitro, which was the highest at a 1.95 M ancymidol.     

Axillary shoot induction and plant regeneration in Plantago ovata Forssk

Axillary shoot induction and plant regeneration were obtained in Plantago ovata. The optimum medium for inducing axillary shoots was Murashige & Skoog (MS) medium [5] supplemented with 4.6 M kinetin and 0.05 M NAA. Rooting of shoots was best on half-strength MS medium containing 5.0 M IBA and 0.05 M kinetin. The regenerated plants were similar to the control plants in karyotypic and phenotypic details.     

Adventitious in vitro plantlet formation from immature floral stems of Crinum macowanii

Adventitious shoots and plantlets were regenerated in vitro from floral stem explants of Crinum macowanii (Bak.) (bush lily). The length (age) of the floral stem as well as the orientation and position of the explant disc in the floral stem were the most important factors affecting shoot regeneration. The highest number of shoots were regenerated when immature floral stems of 70–100 mm were used as starting material, using the middle or basal parts of the stem, and orientating the discs with their proximal ends on the medium. Combinations of kinetin (4.65 M) and either indoleacetic acid (0.57 M) or naphthaleneacetic acid (0.54 M), or a combination of benzyladenine (4.44 M) and 2,4-dichlorophenoxyacetic acid (0.45 M) resulted in the highest numbers of shoots being regenerated. Although a slight degree of callus formation was noticed on the cut-edges of the discs, shoot formation did not occur via callus, but directly from the floral stem epidermis. Unrooted shoots were rooted on MS-medium containing 0.17 M sucrose.Abbreviations BA benzyladenine - IAA indoleacetic acid - IBA indolebutyric acid - NAA naphthaleneacetic acid - 2,4-d 2,4 dichlorophenoxyacetic acid     

Zur Feinstruktur der Elektrozeptorepidermis der Mormyridae (Teleostei,Pisces)

Zusammenfassung Die schwachelektrischen Mormyridae haben eine dreischichtige Epidermis, deren innere Schicht aus nur etwa 0,22 m dicken sechseckigen Zellen von ca. 60 m Durchmesser besteht. Die etwa 2 m dicken, linsenförmigen Kerne von 7,6 m Durchmesser liegen am Zellrand. Die Zellen sind zu Säulen aufgeschichtet. Ihr Rand ist ausgezackt und dort, wo er die Säulengrenze erreicht, auf etwa 0,34 m verdickt. In der Nähe der Säulengrenzen sind die Zellen über Desmosomen mit den Nachbarn in der eigenen und in der angrenzenden Säule verbunden. Diese Epidermisschicht ist auf die Körperpartien beschränkt, in denen auch Elektrorezeptoren ausgebildet sind.Die beiden anderen Epidermisschichten haben den üblichen Aufbau einer Fischepidermis, abgesehen vom Fehlen der Becherzellen.

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Ultrastructure of the electroceptor epidermis of the Mormyridae (Teleostei, Pisces)

Summary The weakly electric fish of the family Mormyridae have a three layered epidermis, with a medium layer consisting of hexagonal cells of only 0.22 m in thickness and about 60 m in diameter. The lens-shaped nuclei are about 2 m thick and 7.6 m in diameter and are situated near the border of the cells. The cells are piled up to hexagonal columns. Their margin is serrate and where it reaches the boundary of the column, it has a thickness of about 0.34 m. Close to the boundaries of the columns, the cells are linked to their neighbours within the column and of the adjoining column by desmosomes. This layer of the epidermis is confined to those regions of the body surface which also contain electroreceptors.The other layers of the epidermis have a structure as usual in fish, except for the lack of goblet cells.

     

Die Länge der Internodien der Markfasern im Bereich der Sehrinde der erwachsenen Katze

Zusammenfassung Die Internodienlänge der Markfasern und ihre Abhängigkeit vom Durchmesser wird durch indirekte Messungen an elektronenmikroskopischen Bildern bestimmt. Der Ranviersche Schnürring wird für die Messung in einen nackten und zwei lamellierte Teile unterteilt (Abb. 1). Die Summenlänge der Markfasern und der Nodien besitzen die in Abb. 4 sichtbare Beziehung zum Durchmesser. Die Internodienlänge beträgt für Markfasern mit einem Durchmesser von 0,4 etwa 40 für solche mit einem Durchmesser von 2,5 etwa 500 . Es wurde eine mittlere Internodienlänge von 90 gefunden. Die Länge aller Markfasern pro mm³ beträgt 590 m; daraus kann eine Anzahl von 6 bis 7 Millionen Ranvierscher Schnürringe pro mm³ errechnet werden. Die Internodienlänge und der Durchmesser stehen wahrscheinlich in einer logarithmischen Beziehung (Abb. 8). In diese logarithmische Beziehung fügen sich die Ergebnisse anderer Autoren gut ein.

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Summary In electron micrographs the internodal length of myelinated fibers and its relation to the diameter has been measured. In this investigation the node of Ranvier is subdivided in three parts, i. e. one non-myelinated and two lamellated parts (Fig. 1). The relationship between the length of the nodes of Ranvier and its diameter is determined (Fig. 4). The internodal length is about 40 for fibers with a diameter of 0.4 and 500 for those with a diameter of 2.5 . The average internodal length is about 90 . The myelinated fibers have a total length of 590 m per mm³; in one mm³ there are therefore 6 to 7 million nodes. The relation between length of internodium and diameter of fiber is probably logarithmic (Fig. 8). The results are compared with similar measurements on peripheral nerves carried out by other authors.

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Mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Pesticides and heavy metals in Danish streambed sediment

The role of streambed sediment as a sink for pesticides and heavy metals was investigated in 30 Danish lowland streams. The investigated streams drain catchments varying in hydrology, topography, soil type and land use. The <250 m newly accumulated fraction of the uppermost 1–2 cm layer of streambed sediment was analysed for 19 old and modern pesticides and 9 heavy metals. DDE was present in the sediment of all the streams. Of the herbicides, fungicides and insecticides currently in use, the most frequently detected was diuron (50.0%), fenpropimorph (66.7%) and lambda-cyhalothrin (6.7%), respectively. The pesticides detected in the highest concentration were fenpropimorph (1700 ng g^–1), propiconazole (130 ng g^–1) and isoproturon (110 ng g^–1). The heavy metals are listed in order of increasing median concentration: Cd (0.80 g g^–1), Co (9.1 g g^–1), As (12.0 g g^–1), Ni (19.0 g g^–1), Cr (19.2 g g^–1), Pb (19.7 g g^–1), Cu (20.1 g g^–1), V (28.5 g g^–1), Zn (103 g g^–1). The average number of pesticides detected in the 27 streams draining predominantly agricultural catchments was (3.7±2.0) being higher (p=0.077) than in the three streams draining non-agricultural catchments (1.7±0.6). Pesticides were significantly related to catchment size, soil type and hydrological regime. Several heavy metals (Cr, Cu, Pb, V and Zn) were related to urban activity and soil type.     

Morphology and structural organization of spiracles in femaleArgas (Persicargas) walkerae (Acari: Argasidae)

Scanning electron microscopical investigations of fractures and corrosion casts of the spiracles from femaleA. walkerae ticks revealed a four-part structure, consisting of spiracular plate, ostium and macula forming the external closure, followed by the subostial space and the vestibulum of regulable volume, as well as the atrial chamber as the innermost part from which the main tracheal trunks originate. On the average, the spiracular plate was 158 m long and 188 m at the broadest width. It consisted of a thin, highly perforated external and a thick internal layer, which enclosed the interpedicellar space with numerous stout pedicels. In its posterior region, the spiracular plate was covered by the macula, which was up to 80 m in length and 110 m in width. The interpedicellar cavity opened into the subostial space measuring 95.5 m in length and 159.6m in width, which proceeded into the 112-m long vestibulum. The roof of the vestibulum was flexible and could be everted and inverted. Inverted, the roof formed a quadratic bulge with numerous deep cuticular folds, which confined the lumen of the vestibulum either partially or completely. In corrosion casts, the roof was everted to a length of up to 89.3 m. In the posterior part of the vestibulum, as well as in the initial fourth of the artrial chamber, numerous anvil-, cone-or drop-like cuticular projections were arranged in wedge-like fashion. The atrial chamber was almost spherical with a diameter of 138.4 m. Five main tracheal trunks of different luminal diameter as well as numerous channels opened into the atrial chamber.     

The use of antibiotics in the culture of non-sterile plant protoplasts

Summary The use of antibiotics to control infections in cultures of protoplasts of leaf mesophyll cells has been examined. The antifungal agents nystatin and amphotericin B were non-toxic to protoplasts at concentrations that controlled fungal growth (25 units and 2.5 g/ml respectively). Of the antibacterial agents examined, only carbenicillin and, to a lesser extent, gentamicin were active against the bacteria usually encountered whilst still permitting normal protoplast metabolism and regeneration. The most satisfactory control of contaminating microorganisms was obtained with a combination of nystatin (25 units/ml) or amphotericin B (2.5 g/ml) and carbenicillin (250 g/ml).     

Influence of sarmesin on some dopamine-related types of behaviour

Summary The present study was undertaken to investigate the effects of sarmesin, an analogue of [Sar¹] angiotensin II (ANG II) where the tyrosine hydroxyl group in position 4 is methylated, on dopamine (DA)-related paradigms: locomotor and exploratory behaviour as well as apomorphine (3 mg/kg, ip)-induced stereotypy in rats. Sarmesin (0.5 and 1 g, icv) significantly decreased ambulation and rearing movements, and blocked the inhibitory effect of ANG II (0.1 g) on both types of activity. Sarmesin induced biphasic effects on apomorphine-induced stereotypy depending on the dose increase (0.5 and 5 g, icv) and decrease (10 g). Moreover, sarmesin (5 g) blocked the inhibitory effect of ANG II (2 g, icv) on apomorphine stereotypy. Taken together, these results suggest that sarmesin might interact with AT₁ and AT₂ receptor subtypes. The results further confirm the statement for ANG II-DA interaction in brain structures involved in these types of behaviour.     

Male reproductive effect of arsenic in mice

Arsenic, a known human carcinogen, was given to mice via drinking water as sodium arsenite at a dose 53.39, 133.47, 266.95 and 533.90 mol l for 35 days. A decrease in the activity of 17 HSD along with increase in LDH, GT activity were observed at 533.90 mol l. The observed sperm count, motility and morphological abnormalities in sperm were similar to control at lower dose levels. However at 533.90 mol l a significant decrease in sperm count and motility along with increase in abnormal sperm were noticed. Significant accumulation of arsenic in testes and accessory sex organs may be attributed to the arsenic binding to the tissues or greater cellular uptake. No effects were observed on indices studied for reproductive effects at 53.39 mol l arsenic close to which human being are exposed through drinking water under the present set of experimental conditions.     

Inhibition of benzo[a]pyrene-induced cytotoxicity and cytochrome P450 1A activity by dietary flavonoids in human liver cell model: structure-activity relationship

Inhibition of benzo[a]pyrene (B[a]P)-induced cytotoxicity and cytochrome p450 1A (CYP 1A) activity by flavonoids (1–100 M) was examined in terms of the structure-activity relationship in the human liver-derived cell model (HepG2). Two hydroxyl groups in the 5- and 7-position of flavonoids were essential to inhibit B[a]P-induced cytotoxicity. Generally, flavones (IC₅₀; 5.0–17.2 M) were more potent than the corresponding flavonols (IC₅₀; 42.7–131.8 M), and flavonoids such as apigenin (IC₅₀; 7.2 M) were more active than the corresponding isoflavonoids, genistein (IC₅₀; 61.7 M). The planar structure of flavone proved to be important in inhibiting B[a]P-induced toxicity and CYP 1A activity. The inhibitory effect of flavonoids on B[a]P-induced CYP 1A activity was correlated well with the inhibition of B[a]P-induced cytotoxicity (r=0.635, p<;0.01).     

Regeneration of plantlets through organogenesis in the Himalayan yellow poppy,Meconopsis paniculata

Plantlet formation through organogenesis in callus cultures of Himalayan yellow poppy,Meconopsis paniculata D.Don (Prain), a threatened taxon of ornamental value, is described. Hypocotyl segments from 3-month-old laboratory-raised seedlings produced callus on agar-solidified Murashige and Skoog medium (MS) containing 10 M -naphthaleneacetic acid and 1 M kinetin. Shoots differentiated best from callus on MS containing 10 M indolebutyric acid (IBA) and 1 M 6-benzyladenine. The regenerated shoots rooted best on MS medium containing 10 M IBA. From seed germination to differentiation of plantlets through the two-step organogenesis process required 28–29 weeks.Abbreviations 2,4-d 2,4-dichlorophenoxyacetic acid - FAA formalin-acetic acid-alcohol - BA 6-benzyladenine - IAA indole-acetic acid - IBA indolebutyric acid - GA₃ gibberellic acid - NAA -naphthaleneacetic acid - RH relative humidity     

Initiation and propagation of Glycine max L. Merr.: Plants from tissue-cultured epicotyls

A successful technique for the initiation and proliferation of shoots from epicotyl tissue of soybean, Glycine max, has been developed and is described. Fertile plants were recovered. Seeds were germinated on Murashige and Skoog medium containing 5 M benzyladenine. Explanted epicotyl sections were induced to form callus and shoots on Schenk and Hildebrandt medium containing 5.2 mM monobasic ammonium phosphate, 74 M 3-aminopyridine, and 20 M kinetin for five weeks. Shoot proliferation was maintained on N6 medium containing 1.75 mM ammonium sulfate, 2.1 nM picloram, and 0.1 M benzyladenine. Shoots rooted on Gamborg's B5 medium without growth regulators. Shoot-forming cultures were maintained for 60 months. Although all varieties tested produced shoots, some variation in numbers of shoots obtained was observed.     

Interactive cytotoxicities of selected organic and inorganic substances to brown cells ofMercenaria mercenaria

Toxicities of binary mixtures of Cu²⁺, Cd²⁺, benzo(a)pyrene [B(a)P] andN-ethylmaleimide (NEM) were screened using thein vitro neutral red (NR) assay to test the hypothesis that combined toxicity is more than or less than additive relative to the influence of each mixture constituent on toxicant uptake and brown cell lysosomal membrane stability. Significant cytotoxicity was observed at 25 mol/L Cu²⁺, 500 mol/L Cd²⁺ and 25 mol/L NEM. B(a)P at 12 mol/L exerted no toxicity under the conditions of the assay. Interactions between Cu²⁺ and NEM, between Cd²⁺ and NEM, and between Cd²⁺ and B(a)P significantly influenced brown cell survival. Comparison of observed joint toxicity with estimates made using a model of independent joint action indicates that interactive effects are less than additive in character. The 3-way interaction involving Cu²⁺, B(a)P, and NEM also affected brown cell survival to a statistically significant degree. However, the interactive cytotoxicity of this mixture is attributable mainly to the combined effect of Cu²⁺ and NEM. Results also indicate that new. hypotheses and additional experimentation are needed to understand the interactive toxicity of mixture constituents.Abbreviations PAH polyaromatic hydrocarbon - NEM N-ethylmaleimide - NR neutral red - B(a)P benzo(a)pyrene     

Effect of mercuric chloride on carbon mineralization in soils

Summary The short and long-term effects of mercuric chloride amendment of five surface soils from southeastern Montana on carbon mineralization was studied. Short-term radiorespirometric studies utilizing a glucose substrate indicated Hg levels greater than 40 g/g soil were required for significant inhibition in all soils tested. Under chronic exposure conditions, levels from 0.1 to greater than 100 g Hg/g soil proved necessary for inhibition.     

Sulfur amino acid metabolism in the developing rhesus monkey brain: Interrelationship of taurine and glutamate

The relationship of taurine to glutamate, and to other amino acids, has been examined in the occipital lobe of the developing rhesus monkey. During development taurine decreases in concentration (4.96 mol/g in fetus to 1.52 mol/g in adult) while glutamate increases (7.92 mol/g in fetus to 11.26 mol/g in adult). When the concentration of taurine is plotted against that of glutamate in fetal, neonatal and adult animals there is a significant correlation in the fetal (p<0.01) and adult (p<0.01) but not in the neonatal occipital lobe samples. This correlation in both fetal and adult brain is specific for these two amino acids. Subcellular fractionation studies further indicate that this relationship may be of special importance in nerve endings.This paper is dedicated to Dr. Derek Richter on his seventy-fifth birthday.