Agarose plating and a bead type culture technique enable and stimulate development of protoplast-derived colonies in a number of plant species

Two novel techniques improve division and colony formation from protoplasts:

1. Plating in agarose stimulates colony formation of protoplasts from a wide range of species. Protoplasts from Nicotiana tabacum developed to colonies from lower initial population densities in agarose than in agar or liquid. Protoplasts from Hyoscyamus muticus which do not divide in agar divided and formed colonies in agarose at higher efficiencies than in liquid medium.
2. Culture of gel embedded protoplasts in large volumes of liquid medium on a gyrotatory shaker (‘bead culture’) further improved plating efficiencies in some species (e.g. Lycopersicon esculentum and Crepis capillaris) and enabled sustained proliferation of protoplasts which had not previously developed beyond the few cell colony stage (Brassica rapa and a mutator gene variety of Petunia hybrida).

The combination of ‘agarose plating’ and ‘bead culture’ dramatically improved plating efficiencies of protoplasts in all species tested.     

Influence of the coral reef assemblages on the spatial distribution of echinoderms in a gradient of human impacts along the tropical Mexican Pacific

Fourteen species of echinoderms and their relationships to the benthic structure of the coral reefs were assessed at 27 sites—with different levels of human disturbances—along the coast of the Mexican Central Pacific. Diadema mexicanum and Phataria unifascialis were the most abundant species. The spatial variation of the echinoderm assemblages showed that D. mexicanum, Eucidaris thouarsii, P. unifascialis, Centrostephanus coronatus, Toxopneustes roseus, Holothuria fuscocinerea, Cucumaria flamma, and Echinometra vanbrunti accounted for the dissimilarities among the sites. The spatial variation among the sites was mainly explained by the cover of the hard corals (Porites, Pocillopora, Pavona, Psammocora), different macroalgae species (turf, encrusting calcareous algae, articulated calcareous algae, fleshy macroalgae), sponges, bryozoans, rocky, coral rubble, sand, soft corals (hydrocorals and octocorals), Tubastrea coccinea coral, Balanus spp., and water depth. The coverage of Porites, Pavona, and Pocillopora corals, soft coral, rock, and Balanos shows a positive relationship with the sampling sites included within the natural protected area with low human disturbances. Contrary, fleshy macroalgae, sponges, and soft coral show a positive relationship with higher disturbance sites. The results presented here show the importance of protecting the structural heterogeneity of coral reef habitats because it is a significant factor for the distribution of echinoderm species and can contribute to the design of conservation programs for the coral reef ecosystem.     

A proof of the DBRF-MEGN method, an algorithm for deducing minimum equivalent gene networks

Background

We previously developed the DBRF-MEGN (difference-based regulation finding-minimum equivalent gene network) method, which deduces the most parsimonious signed directed graphs (SDGs) consistent with expression profiles of single-gene deletion mutants. However, until the present study, we have not presented the details of the method's algorithm or a proof of the algorithm.

Results

We describe in detail the algorithm of the DBRF-MEGN method and prove that the algorithm deduces all of the exact solutions of the most parsimonious SDGs consistent with expression profiles of gene deletion mutants.

Conclusions

The DBRF-MEGN method provides all of the exact solutions of the most parsimonious SDGs consistent with expression profiles of gene deletion mutants.     

Indole alkaloids from cell suspension cultures of Tabernaemontana divaricata and Tabernanthe iboga

From cell suspension cultures of Tabernaemontana divaricata and Tabernanthe iboga grown under standard conditions, six monoterpenoid indole alkaloids have been isolated and identified. T. divaricata synthesized apparicine, catharanthine, coronaridine, conoflorine, tubotaiwine and vinervine, whereas T. iboga produced tubotaiwine and conoflorine. Both cultures are a reasonable source for conoflorine, which is expected to be a good candidate for studying the mechanism of Aspidosperma type alkaloid formation at the cell-free level.     

Towards a noninvasive anatomical and functional diagnostic work-up of patients with suspected coronary artery disease

Combining multidetector computed tomography and cardiovascular magnetic resonance imaging provides the clinician a strategy to comprehensively evaluate coronary morphology and function noninvasively. In the MARCC trial (Magnetic Resonance and CT in suspected CAD) a new noninvasive diagnostic work-up for patients with suspected coronary artery disease will be developed, involving the sequential use of both imaging techniques. (Neth Heart J 2010;18:270-3.)     

Triassic reefs in Slovenia

The paper deals with the distribution, paleogeography, age and biota of Triassic reefs in Slovenia. Most of these reefs have not been studied in detail up to now, but the paleographical distributional pattern can be outlined (Figs. 1 and 2). Triassic reefs are known from Central and Northern Slovenia, predominantly occurring at the margins of the “Slovenian trough” (which separates the northern Julian Platform and the southern Dinaric Platform) and at the margins of an intraplatform trough within the Julian platform. Reef growth started in the Ladinian and Cordevolian and continued (with interruptions during the Upper Carnian ?) to the Norian and Rhaetian. Anisian environments are characterized by the predominance of algal mats and dasycladacean algae. Cordevolian patch reefs as well as Norian and Rhaetian reefs were built during the Late Triassic by calcareous sponges and corals, which belong to different species (Tab. 1 and 2). Some smaller Cordevolian patch reefs may have been formed within deeper-water sediments. An interesting facies sequence is developed in the Norian Dachstein Limestone reef of Pokljuka (Julian Alps), starting with deeper-marine cherty limestones, which gradually succeeded by crinoidal limestones followed by reef limestones and lagoonal Dachstein Limestones.     

A study on the rate of water transport of the clam katelysia opima in relation to environmental conditions

1. The neutral red technique was employed to study the rate of filtration in Katelysia opima.
2. The weight specific water filtration was found to be greater for younger clams compared to the older ones.
3. The rate of water filtration increased with decreasing salinity.
4. Water filtration was found to increase as temperature increased, reaching a maximum at 35°C. but then sharply decreasing at 39°C.
5. Light had no significant effect on the rate of filtration.
6. Suspended matter was found to affect the rate of water filtration.
7. The rate of filtration was low at high pH and high in low pH.
8. The rate of water filtration was found to be faster during high tide than during low tide.
9. The presence of the parasitic crab, Pennotheris sp., in the mantle cavity of clams had a marked effect on the particle filtration.
10. Accidental cut of the siphon tips had no effect on the rate of filtration.

     

Paleoecologic,temporal, and spatial analysis of early Silurian Reefs of the Chicotte Formation,Anticosti Island,Quebec, Canada

Summary Reefs of the Lower Silurian Chicotte Formation are the largest and most faunally diverse known on Anticosti Island, Quebec. They reach up to 25 m in thickness and 250 m in diameter and are present predominantly at two intervals, forming a lower and upper reef cluster. Remnants of bioherms are represented on the present-day wave-cut terrace as 60 to 100 m diameter, subcircular erosional depressions known as Philip structures or as outcrop. The bioherms were relatively low structures, with approximately 3 to 5 m maximum synoptic relief, some of which developed on hardgrounds and possible paleokarst surfaces of crinoidal wackestone and packstone. Dominant skeletal framework builders and sediment producers within all of the reefs are laminar to low domical stromatoporoids, colonial cerioid and fasciculate rugose corals, colonial tabulate corals, and cryptostome bryozoans. Vertical zonation of reef biota is evident within well-exposed reefs of the lower reef cluster. Three to four stages are recognizable:1) a low-diversity tabulate coral-dominatedpioneering community including large tabulate coral colonies (halysitids and favositids), and few stromatoporoids (clathrodictyids, ecclimadictyids), fasciculate rugosans, large generally monotypic stalked crinoids, and shelly benthos (brachiopods, few ostracodes and trilobites);2) an intermediate- to high-diversity, mixed tabulate coral-stromatoporoid-dominatedreef-core community;3) a slightly lower diversity stromatoporoid-tabulate coral-dominatedclimax community with laminar coenitids and alveolitids; and,4) in a few localities, a capping, low-diversity tabulatecoral-dominated (alveolitid and coenitid), and stromatoporoid-bearing community comprising laminar forms. Amelioration of Early Silurian climates, following Late Ordovician glaciation, allowed gradual reestablishment of extensive shallow-water reef growth, by mainly new and increasingly diverse genera and species of metazoans. Reef development within the Chicotte Formation coincided with global, widespread development of latest Llandovery and earliest Wenlock reefs in subtropical to tropical areas. Chicotte reefs have broad characteristics, in terms of overall biotic composition, vertical successions recognized, and paleogeographic setting, similar to those of equivalent and slightly younger age from intracratonic settings in Baltica (Gotland, Sweden and Estonia) and central and northern Laurentia (Midcontinent, U.S.A.; Hudson Bay, Canada; and North Greenland, Denmark).     

Isolation and characterization of DNA sequences from Triticum aestivum which function as origins of replication in Saccharomyces cerevisiae

Recombinant YIp5 plasmids with the DNA from Triticum aestivum are capable of autonomous replication in Saccharomyces cerevisiae. The URA transformants are unstable without selection pressure, and transformation of yeast cells with these plasmids occurs at high frequency. The cloned sequences were characterized and analyzed to state their belonging to Triticum tribe.     

High production of caffeine and related enzyme activities in callus cultures of Coffea arabica L.

Callus tissue culture of Coffea arabica L. cv Hybrido de Timor prepared from apical portions of orthotropic branches produced 49 to 92 times as much caffeine per unit weight of tissue as did the original explant. Cell-free extracts made from 42 to 54-day-old callus cultures in which active biosynthesis was occurring exhibited N-methyl-N ⁹-nucleoside hydrolase and N-methyltransferase enzyme activities. Similar cell-free extracts exhibited selective biodegradative activity in forming urea from xanthine. Biosynthetic substrate specificities are similar to those of the enzyme obtained from green coffee fruit and tea leaves, suggesting that callus cultures of C. arabica form caffeine in the same way as the coffee fruit and tea leaves.     

Photostimulated formation of radicals on oxide surfaces

We present results ofin situ EPR investigations of the mechanism of photostimulated processes resulting in radical and ion-radical particle formation on the surfaces of oxide dielectrics (magnesium, calcium, aluminum oxides, zeolites). Three types of reactions are discussed:

1. Formation of oxygen anion-radicals on MgO and CaO surfaces.
2. Formation of benzene cation-radicals on ZSM-5 zeolites.
3. Formation of radical particles from aromatic nitrocompounds adsorbed on alumina.

On the basis of investigation of the spectral relationships and the properties of surface active centre, it is concluded that light is absorbed by coordinatively unsaturated surface sites in the first system, whereas in the other processes, electron donor-acceptor (EDA) complexes between adsorbed molecules and surface active sites are supposed to be key intermediates. These EDA complexes are shown to incorporate donor solvent molecules as well. In this case the energetic characteristics of the photoprocesses are substantially determined by the ionization potential of solvent molecules. Mechanisms of photo- and thermostimulated processes are compared and possible similarities are discussed for all the reactions studied.     

Experimental problems using electronic particle counters

The following scheme lists the problems which have been and will continue to be encountered in grazing experiments on natural particle assemblages. In some cases there are solutions, but many of the problems listed below remain intractable. To solve them will require innovative approaches, most probably combining the use of particle counters with other techniques to approach the problem to be solved from several angles at once. Variance between samples due to

- statistical causes (especially caused by large particles) and

- differences between experimental bottles and between experimentals and controls at start of experiment. Shifts in particle distribution during experiment due to

- increase in small particles

- growth of bacteria and other organisms due to excretion of grazers and

- breakage during handling by grazers into fragments. Processes, independent of grazing, leading to changes in particle size distribution due to

- primary production

- grazing by additional components and

- bacterial growth on detrital particles and the formation of detrital flocs.

     

The use of toxicokinetics for the safety assessment of drugs acting in the brain

Pharmacological and toxicological studies undertaken on drugs that affect the brain are frequently performed in disparate species under various experimental conditions, at doses often greatly in excess of those expected to be administered to humans, and the findings are extrapolated implicitly or explicitly with scant regard to differences in the biodisposition of the drugs. Such considerations are necessary since:

1. Species;
2. Strain;
3. Gender;
4. Route;
5. Dose;
6. Frequency and time of administration;
7. Temperature;
8. Coadministration of drugs; and
9. Surgical manipulation

are but some of the factors that have been shown to influence the kinetics and metabolism of drugs. This article, using MDMA and other phenylethylamines as examples, provides evidence for the need to measure the exoosure of the drugs and their active metabolites in blood and brain (toxicokinetics) in order that conclusions based only on dynamic, biochemical, or histological evidence are more pertinent. Further, the combined use of toxicokinetic-dynamic modeling can lead to a better appreciation of the mechanisms involved and a more useful approach to the calculation of safety margins.     

Effet des androgènes sur l’activité sportive

Androgenic hormones seem to be of beneficial effects on sports performance:

- they increase motivation, will, aggressiveness, resistance to the stress and to the fatigue, leading to an increase of the training quantity,

- they increase bone mineralization and probably mechanical resistance,

- they stimulate the bone marrow and so, with the erythropoietin, the erythropoiesis,

- they increase the tendancy to hyperglycemia, but with a decrease of the tolerance to the glucose,

- they stimulate the fatty acids mobilization from the adipose tissue, for their utilization in the muscle during the exercise,

- they participate, for the trained sportmen, to a better gestion of the muscle glycogen storage: their utilization during exercise is decreased,

- they increase the lean body mass, with an increase of the protein synthesis and a decrease of the protein catabolism, leading also to an increase of the muscle force under training. There is no beneficial effect upon the tendons,

- they have an immunomodulation action.

     

Reduced ethanol tolerance: One of the pleiotropic effects of the pep4.3 mutation in Saccharomyces cerevisiae

Yeast strains carrying the single nuclear mutation pep4.3 are deficient in the activity of a number of vacuolar hydrolases. This paper demonstrates that the pep4.3 mutation also renders yeast more sensitive to the growth inhibitory effects of ethanol. This sensitivity to ethanol is a temperature-conditional phenomenon and suggests some general effect of the pep4.3 mutation on yeast membranes.     

The use of a continuous assay system to show the stimulation of phosphoenolpyruvate production in intact mitochondria by valinomycin and by Mn2+

1. A method for the direct recording of the PEP efflux from isolated mitochondria is described.
2. This method has been used to show the stimulation of PEP efflux by externally added Mn⁺⁺ ions.
3. Valinomycin, uncoupler and oleate were also shown to stimulate PEP efflux.
4. Valinomycin caused an increase in the internal concentration of both PEP and citrate.
5. The results indicate that the major pathway of PEP synthesis in isolated mitochondria is via PEP carboxykinase and the results do not call for an unknown pathway of metabolism.
6. Two interactions between PEP and citrate are described; competition for the mitochondrial interior and the stimulation of PEP production by citrate.

     

Mesophotic reef fish assemblages of the remote St. Peter and St. Paul’s Archipelago,Mid-Atlantic Ridge,Brazil

Mesophotic reef fish assemblages (30–90 m depth) of the small and remote St. Peter and St. Paul’s Archipelago (SPSPA), Mid-Atlantic Ridge, Brazil, were characterized using remotely operated vehicles. Ordination analyses identified distinct fish assemblages in the upper (30–50 m) and lower (50–90 m) mesophotic zones, the former characterized by high abundances of species that are also abundant at euphotic reefs (Caranx lugubris, Melichthys niger, Stegastes sanctipauli and Chromis multilineata) and the latter dominated by two mesophotic specialists (Prognathodes obliquus and Chromis enchrysura). Planktivores dominated fish assemblages, particularly in the upper mesophotic zone, possibly due to a greater availability of zooplankton coming from the colder Equatorial Undercurrent in mesophotic depths of the SPSPA. Turf algae, fleshy macroalgae and scleractinian corals dominated benthic assemblages between 30 and 40 m depth, while bryozoans, black corals and sponges dominated between 40 and 90 m depth. Canonical correspondence analysis explained 74 % of the relationship between environmental characteristics (depth, benthic cover and complexity) and structure of fish assemblages, with depth as the most important independent variable. Juveniles of Bodianus insularis and adults of P. obliquus and C. enchrysura were clearly associated with branching black corals (Tanacetipathes spp.), suggesting that black corals play key ecological roles in lower mesophotic reefs of the SPSPA. Results from this study add to the global database about mesophotic reef ecosystems (MREs) and provide a baseline for future evaluations of possible anthropogenic and natural disturbances on MREs of the SPSPA.     

Anaerobic respiration in latex ofHevea brasiliensis substrate and limiting factors

The site of anaerobic respiration in the latex is the serum. The main respiratory substrate is fructose. The CO₂ formation in serum is increased by additional fructose on the average about 2.5–3 times. Glucose does not influence CO₂ evolution by serum but slightly increases O₂ consumption. With respect to sugars, latex serum contains essentially only sucrose and a low amount of raffinose. During the incubation of serum sucrose is hydrolysed, the fructose component is immediately utilized in respiration and glucose accumulates. The rate of CO₂ formation in latex as influenced by fructose is negatively related to the rubber content of the latex. Latex with a high rubber content reacts only slightly or not at all on additional fructose. The main limiting factors of latex respiration and sugar utilization are the following:

1. The deficiency of substrate, due to low activity of β-fructofuranosidase.
2. The rate of glucose phosphorylation (D'Auzac, Jacob 1967).
3. Presumably the low activity of phosphoglucoisomerase.
4. The rubber content of the latex.
5. The concentration of CO₂ in latex; this factor may be important in vivo, in the laticiferous system.