Promotion of indole alkaloid production in Catharanthus roseus cell cultures by rare earth elements

Production of the indole alkaloids, ajmalicine or catharanthine, in cell suspension cultures of Catharanthus roseus was enhanced by cerium (CeO₂ and CeCl₃), yttrium (Y₂O₃) and neodymium (NdCl₃). The yield of ajmalicine in these treated-cultures reached 51 mg l^–1 (CeO₂), 40 mg l^–1 (CeCl₃), 41 mg l^–1 (Y₂O₃) and 49 mg l^–1 (NdCl₃) while catharanthine production reached to 36 mg l^–1 (CeO₂) and 31 mg l^–1 (CeCl₃). A major portion of increased alkaloids was released into medium in these treatments. But Sm₂O₃, SmCl₃, La₂O₃, LaCl₃, complex of chromium (III)-titanium (IV) and NaSeO₄ treatments had little effect on alkaloid production of C. roseus cell cultures.     

喜树叶、枝水溶性糖提取的研究

用正交实验结果作方差分析表明：溶剂用量对试验结果有较显著的影响（a=0.10)，提取温度对试验结果也有较大的影响，而提取时间对试验结果的影响不显著。喜树叶中水溶性糖的提取最优方案是A3C2B3，即溶剂用量为60ml，提取温度80℃，提取时间60min；喜树叶水溶性糖的提取最优方案是A2C2B1，即溶剂用量为40ml，提取温度80℃，提取时间20min。通过对喜树叶与枝的成对比较分析，叶与枝的水溶性糖含量无显著差异。     

Interactions of target population size,population parameters,and program management on viability of captive populations

When established conservation programs expand and evolve, management practices may become inconsistent with program goals. In the past decade, the American Zoo and Aquarium Association expanded species conservation programs by increasing the number of Species Survival Plans (SSP) and establishing more than 300 new Population Management Plan (PMP) programs. However, limited space in captive breeding facilities forces a competition among SSPs and less intensively managed PMPs. Regional Collection Plans establish priorities and allocate space accordingly by setting target population size for each species; species of high conservation priority (SSPs) are allocated space at the expense of lower priority species (PMPs). Because population size and genetic composition interact to impact population viability, target population size is a significant factor to a population’s prospects for long‐term survival. We examined four population parameters (current population size, target population size, current gene diversity, and mean generation time) for 46 mammalian SSPs and 17 PMPs. Relative to SSPs, PMPs combine smaller current and target population sizes, lower levels of current gene diversity, and shorter mean generation times than SSPs. Thus, the average PMP population can expect to lose gene diversity more rapidly than the average SSP population. PMPs are projected to lose 10% or more of their founding gene diversity, within only 2 years. In contrast, the average SSP population is projected to lose 10% in 40 years. Populations with small current or target population sizes require intensive management to avoid extinction. More intensive genetic management of populations typically designated as PMPs, through recruitment of potential founders and equalization of founder representation, could increase gene diversity and improve viability. Less rigorous population management should be reserved for populations whose long‐term survival is either secure or that can be readily replenished from the wild. Because PMP populations need intense genetic management similar to that currently in effect for SSPs, there should be neither a management‐level distinction between programs nor an arbitrary difference in space allocated to programs. Zoo Biol 20:169–183, 2001. © 2001 Wiley‐Liss, Inc.     

Scale-dependent effects of windthrow disturbance on forest arthropod communities

The effect of disturbance on local communities may operate within the context of the spatial landscape. We examined the scale-dependent effects of windthrow disturbance caused by a large typhoon on three arthropod communities in a temperate forest of Japan. Canopy arthropods were collected by beating foliage, forest-floor arthropods were collected by sweeping the vegetation, and flying arthropods were collected in Malaise traps. To assess the “functional spatial scale” at which arthropods responded to tree-fall disturbance, the gap rate was quantified at different spatial scales by sequentially enlarging the radius of a circular landscape sector in 10-m increments from 10 to 500 m. We then analyzed the responses of order richness and abundance to the gap rate for each arthropod community. The spatial scale of the significant best-fitting model, which was selected from the models fitted to the gap rate at stepwise spatial scales, was regarded as the arthropod-specific functional spatial scale. Arthropod order richness was not dependent on the gap rate. In contrast, arthropod order abundance depended significantly on the gap rate in many orders, but varied in the response direction and functional spatial scale. These order-specific, scale-dependent responses to tree-fall gaps could complicate interactions among organisms, leading to complex community organization. An understanding of the spatial processes that link the use of space by organisms with the spatial scale at which ecological processes are experienced is required to elucidate the responses of populations, communities, and biotic interactions to disturbances in a spatial landscape context.     

Effect of NaCl salinity in vivo and in vitro on ribonuclease activity in the halophyte Suaeda maritima

Ribonuclease (EC 2.7.7.17) activity in the obligate halophyte Suaeda maritima (L.) Dum. var. macrocarpa Moq. was studied in relation to salinity (increasing concentrations of NaCl) of incubation and growth media. In vitro, the addition of 50 to 400 m M NaCl did not affect ribonuclease activity. This result, which was also found for Phaseolus vulgaris , indicates that the hydrolase is insensitive to high saline concentrations. The subcellular distribution of RNase activity did not change significantly with the salinity of the medium or with the age of the plant. The microsomal ribonuclease activity expressed on a fresh weight basis represented in every case less than 6% of the total activity. After 23 days of culture, the absence of salt stimulated the activity of soluble ribonuclease in aerial parts of Suaeda ; inversely, the capacity of the enzyme was lower under optimal saline conditions (130 m M NaCl). This was also evidenced by transfer of whole plants from a non-saline to a saline medium. Such a saline shock caused a decrease followed by a stabilization of the capacity of ribonuclease from Suaeda . The influx of NaCl in the tissues lowered the activity of the hydrolase.     

Pinocytose und Bewegung von Amöben

Zusammenfassung Zur Bestimmung des cytotischen Membran-Turnovers wurden morphometrische Messungen an über 60 Zellen der Art Amoeba proteus durchgeführt. Danach nehmen diese Amöben 0,14% ihrer Zelloberfläche pro Minute durch permanente Endocytose in das Cytoplasma auf. A. proteus benötigt also insgesamt 12 Std, um die gesamte Zellmembran während der normalen Bewegung einmal zu erneuern. Infolge des geringen Membranturnovers kann der permanenten Endocytose keine aktive Bedeutung für die Erzeugung der Bewegungstriebkraft zugesprochen werden. In Übereinstimmung mit dieser Vermutung ließ sich eine Abhängigkeit zwischen Fortbewegungsgeschwindigkeit und Endocytoseintensität nicht nachweisen.Entsprechende Messungen mit drei verschiedenen Endocytoseinduktoren ergaben für die induzierte Endocytose in Abhängigkeit von der verwendeten Substanz eine wesentlich höhere Ingestionsrate von 0,43–2,25%/min. Derartige Spitzenwerte können allerdings nur innerhalb eng begrenzter Zeiträume von 15–30 min erzielt werden. Vergleicht man dagegen die Membranaufnahme während der permanenten und induzierten Endocytose über längere Zeitintervalle (4–5 Std), so bleibt die induzierte Endocytose mit 0,05–0,12%/min in der Intensität deutlich hinter der permanenten Endocytose (0,14%/min) zurück. Eine Erhöhung der Temperatur auf 30° und eine Erniedrigung auf 15°C bringen beide Endocytoseformen zum Erliegen.Die permanente Endocytose muß bei Amöben neben der Phagocytose als der wichtigste Mechanismus zur kontinuierlichen Aufnahme gelöster und suspendierter Stoffe (bis zur Größenordnung von Bakterien) angesehen werden.

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Pinocytosis and locomotion of amoebae

Summary Cytotic membrane turnover of Amoeba proteus was morphometrically studied in more than 60 cells. The results obtained indicate that 0.14% of the total cell membrane area per minute is ingested by permanent endocytosis. Consequently during normal locomotion the total cell membrane area is renewed once within 12 hours.This rate is too low to play any role in the generation of motive force. No correlations were found between the rates of locomotion and permanent endocytosis.Comparative measurements on cells treated with three different substances inducing endocytosis reveal that induced endocytosis leads to an increased rate of membrane ingestion of 0.43–2.25%/min depending on the substance used. These high rates, however, are only maintained during short periods of time (15–30 min). When the rates are calculated on the basis of long periods of time (4–5 hours), it is obvious that induced endocytosis (0.05–0.12%/min) is less effective in long term membrane turnover than permanent endocytosis (0.14%/min). Endocytotic activity is completely abolished by both the increase and decrease in temperature to 30°C and 15°C respectively.In addition to discontinuous phagocytosis permanent endocytosis is an important mechanism for continuous ingestion of fluid including particles up to the size of bacteria.

Der Kultusminister des Landes Nordrhein-Westfalen unterstützte die Untersuchung aus Überschußmitteln des Westdeutschen Rundfunks.     

Use of molecular markers in participatory plant breeding: assessing the genetic variability in cotton populations bred by farmers

In participatory plant breeding, farmers are involved in simple selection schemes that are not suitable for assessing genetic variability in the segregating populations. We propose to use information derived from molecular marker analyses to help monitoring such populations. In this study, we used three indicators to compare genetic variability in eight genetic structures, that is three plant populations selected by farmers over five generations, three nonselected populations and two commercial varieties. The three indicators were the polymorphic locus rate, heterozygosity rate and dissimilarity index. The results highlighted that the genetic variability decreased more with farmers’ selection than with environmental factors. The breeding process was not complete because genetic variability in the selected populations was midway between that of the nonselected populations and that of the commercial varieties monitored. The three proposed indicators were relevant for describing the studied populations. They could be interpreted according to a grid drawn up on the basis of the results of the present study.     

Dimeric chromenes and mixed dimers of a chromene with euparin from Encelia canescens

The investigation of Encelia canescens afforded, in addition to several known compounds, four new dimeric p-hydroxyacetophenone derivatives, two epimeric chromene dimers and two epimeric mixed dimers of euparin and encecalin. Furthermore, derivatives of tremetone and of encecalin were present. The structures were elucidated hy high field ¹H NMR spectroscopy.     

Relationship of lower limb height to sitting height in black populations of Africa and the United States.

This article examines a recently reported generalization. Materials from more than a score of invetigations are drawn upon. These materials show there is not a substantial research base for the claim that interbreeding in the United States between black people of African ancestry and white people of European ancestry has resulted in increased lower limb height relative to sitting height.