A comparison of the pre-calling period between Japanese and southeastern Asian populations of Spodoptera litura

The pre-calling behavior of female adults of the common cutworm, Spodoptera litura （Lepidoptera： Noctuidae） collected in southern Japan and southeastern Asian countries was investigated. Most females started calling on days 1-4 after adult emergence. In three populations obtained in Saga prefecture in Kyushu mainland, Japan, two different patterns of pre-calling period （PCP） were observed： one was the above-mentioned pattern shown by most individuals, and the other was a pattern in which females sexually matured within several hours after emergence. Diel periodicity was shown in the time of calling activity, and its pattern varied among the populations. Pre-calling period was stable over successive generations in the laboratory.     

Sequence Diversity and Linkage Disequilibrium within the Merozoite Surface Protein-1 (Msp-1) Locus of Plasmodium falciparum: A Longitudinal Study in Brazil

ABSTRACT. The merozoite surface protein‐1 (MSP‐1) is a major vaccine candidate for the asexual blood stage of malaria. We examined both the extent of sequence diversity in block 17, the 3′end of Msp‐1 gene coding for a 19‐kDa polypeptide (MSP‐1₁₉) putatively involved in red blood cell binding, and the patterns of linkage disequilibrium between polymorphic sites throughout the Msp‐1 locus. The parasite population sample consisted of Plasmodium falciparum isolates collected between 1985 and 1998 in Rondônia. an area of hypoendemic malaria transmission in the southwestern Brazilian Amazon. Results were summarized as follows. (I) Seven block‐17 sequence variants or haplotypes were found among 130 isolates, including two new haplotypes (novel combinations of previously reported amino acid replacements), here named Brazil‐1 (E‐TSR‐F) and Brazil‐2 (Q‐TSR‐F). (2) As previously shown for other Msp‐1 polymorphisms, frequencies of block‐17 haplotypes displayed significant temporal variation. (3) Extensive linkage disequilibrium was demonstrated between neighboring dimorphic sites within block 17, as well as between polymorphisms at the 5′and 3′ends of Msp‐1 (map distance range: 3.83–4.99 kb). (4) The overall patterns of linkage disequilibrium within Msp‐1 remained stable over a period of nearly one decade, and examples of possible ‘epidemic’ expansion of parasites carrying particular Msp‐1 alleles were found in the 1980s and 1990s. These results are discussed in relation to the population biology of P. falciparum and the development of malaria vaccines based on MSP‐1.     

The relationship between aryl hydrocarbon hydroxylase activity and DNA adducts measured by 32P-postlabelling assay in lymphocytes of lung cancer patients

We have investigated the correlation between DNA adduct levels and aryl hydrocarbon hydroxylase (AHH) activity in peripheral lymphocyte samples obtained from 42 lung cancer patients. DNA adducts and AHH activity were determined by the ³²P-postlabelling technique and the fluorometric method, respectively. The mean +/- SD of DNA adduct level was 0.88 +/- 0.37 (ranged from 0.22 to 1.90) per 10⁸ nucleotides. The geometric means of non-induced and 3-methylcholanthrene (MC)-induced AHH activity, as well as AHH inducibility (MC-induced AHH activity/non-induced AHH activity) were 0.029, 0.228 pmol min^-1 10^-6 cells, and 7.776, respectively. There was no statistically significant correlation between DNA adduct levels and non-induced or MC-induced AHH activity. A tendency of positive correlation was found between DNA adduct levels and AHH inducibility for the all subjects (n = 42, r = 0.25, p = 0.11). Such a positive correlation reached statistical significance in the subjects with squamous cell carcinoma (n = 13, r = 0.70, p < 0.01). In addition, similar correlation of DNA adducts with AHH inducibility was also observed in the GSTM1 present genotype (n = 17, r = 0.44, p = 0.07) and GSTP1-AA genotype (n = 29, r = 0.37, p = 0.05) individuals. These findings suggest that DNA adduct levels are mediated by CYP1A1 enzyme, and AHH inducibility may be a more relevant indicator than specific AHH activity for explaining the variation of DNA adduct levels in lymphocytes.     

Flexible Leaf Orientations ofArisaema heterophyllumMaximize Light Capture in a Forest Understorey and Avoid Excess Irradiance at a Deforested Site

Effects of flexible leaflet orientations on light capture andphotosynthesis were investigated forArisaema heterophyllumBlume,a perennial herb with a single palmately compound leaf, in twocontrasting light environments: a riparian forest understoreyand an adjacent deforested open site. Leaf orientations aredetermined by inclination of leaflet midvein and folding ofleaflet blade. Leaves were flatter and had smaller angles ofinclination at the forest site than at the deforested site.Directions (angular altitude and azimuth) of leaf surfaces ofthe forest site plants were close to those predicted to maximizediffuse light capture at each microsite, as determined by theanalysis of a hemispherical canopy photograph. Mean light captureefficiency (the ratio of actual diffuse light capture by a leafto maximal receivable light) reached 98%. In contrast, markedleaflet folding occurred only at the deforested site. The degreeof folding varied diurnally with the maximum around noon. Computersimulations showed that PPFDs (photosynthetically active photonflux density) over the photosynthetic saturation level ofA.heterophyllumcan be effectively reduced by increasing the slopeof leaflet surfaces. The importance of decreasing excess irradianceto avoid photoinhibition and to maintain high rates of photosynthesiswas confirmed by artificially constraining leaves horizontally.Copyright1998 Annals of Botany Company Arisaema heterophyllumBlume, forest understorey, hemispherical canopy photograph, high light stress, leaf orientation, light capture efficiency, microsite light availability, midday depression, photoinhibition, photosynthesis.     

Plant-Herbivore Interactions and Theory of Coevolution1

Abstract We consider a mathematical model for the coevolution of a plant's defense against herbivores and the herbivore's ability to exploit the plant. The result of coevolution is predicted using the phase portrait of trait value dynamics and contour plots of fitnesses. The following results are derived: (1) The fitnesses of both plant and herbivore are higher at an “armless” state in which both plant and herbivore invest a minimum amount of energy and/or resources in defense and feeding respectively, than at the coevolutionarily stable state (CSS); (2) Perpetual increase in the trait values of both species may occur when the marginal costs of defense and feeding abilities decrease as these abilities increase; (3) If the marginal costs of defense and feeding abilities increase as the abilities increase, there is a coevolutionary equilibrium with finite trait values; (4) There may be more than one coevolutionarily stable state (CSS).     

Growth of Individuals in Plant Populations

Relationships between individual plant weight and net photosynthesisper day (G(t, x) function of plant weight) in plant populationsof various stand structures were simulated based on a canopyphotosynthesis model. The G(t, x) functions of plant weightare determined mainly by LAI (leaf area index), the relationshipbetween individual plant weight and leaf area, canopy structureand extinction coefficient. The concave relationship betweenindividual plant weight and leaf area at small LAI (<2),at small extinction coefficient (< 0.5), or at the canopystructure having the maximum leaf area density at the bottomproduces a concave G(t, x) function, which generates negativeskewness of plant weight. The linear relationship between individualplant weight and leaf area at large LAI (> 2) produces aconvex G(t, x) function, which generates positive skewness ofplant weight. These simulation results coincide with G(t, x)functions obtained experimentally and with the well-known phenomenonof stand dynamics in which skewness of plant weight becomesnegative in the early growth stage and then increases to a positivevalue as a stand grows and becomes crowded. Helianthus annuus L., individual plant size, mean growth rate, canopy photosynthesis model, skewness, stand structure     

Biochemical Studies on the Acrosome Reaction of the Starfish, Asterias Amurensis II. Purification and Characterization of Acrosome Reaction-Inducing Substance

The acrosome reaction-inducing substance (ARIS) was purified from egg jelly of the starfish, Asterias amurensis. The purification procedure included elimination of neutral glycoproteins from the ARIS fraction by isoelectric pointprecipitation and subsequent gel filtrations on Sephadex G–50 and Bio-Gel A-50m columns. The final preparation of ARIS was homogeneous as judged by cellulose acetate electrophoresis of ARIS and by ion-exchange chromatography on DEAE-Sephadex A–25 of S-carboxymethylated ARIS. ARIS is a very large, sulfated glycoprotein containing fucose, galactose, galactosamine and glucosamine as sugar components. It requires diffusible cofactor (Co-ARIS) for full biological activity. A Pronase digest of ARIS retained its capacity to induce the acrosome reaction when Co-ARIS was added to the bioassay system. The physiological significance of the carbohydrate moiety of ARIS is discussed.     

Mitosis in Beating Cardiac Muscle Cells from Newt Embryos In Vitro

Cardiac muscle cells from newt embryos were cultured at relatively low cell density. Within 10 days in culture, 2 cell types (spindle and flat type) were distinguished both among beating and non-beating cells. Mitosis in single beating cells was frequently observed both in spindle and flat cells. Some cells maintained almost constant contractile activities throughout the mitotic stages, while the others transiently stopped beating during mitosis, which accords well to the case in chick embryos (1). Ultra-thin section shows the presence of myofibril's structure in a dividing cell, as shown in newborn rats (2, 3, 4), chick embryos (1, 5, 6, 7) and adult newts (8, 9). As a consequence of mitosis, 3 types (spindle, flat and mixed type) of beating colonies developed after 34 weeks in culture. Cell proliferation was accompanied with pulsation and could be directly pursued till the 4th division, suggesting that differentiated myocardiac cells with myofibrils proliferate by their mitoses in vivo , maintaining rhythmic contraction.