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PubMed2000

Development of a plant growth unit for growing plants over a long-term life cycle under microgravity conditions.

To study the effect of the space environment on plant growth including the reproductive growth and genetic aberration for a long-term plant life cycle, we have initiated development of a new type of facility for growing plants under microgravity conditions. The facility is constructed with subsystems for controlling environmental elements. In this paper, the concept of the facility design is outlined. Subsystems controlling air temperature, humidity, CO2 concentration, light and air circulation around plants and delivering recycled water and nutrients to roots are the major concerns. Plant experiments for developing the facility and future plant experiments with the completed facility are also overviewed. We intend to install this facility in the Japan Experiment Facility (JEM) boarded on the International Space Station.

Air Conditioning↗
PubMed2002

Assessing human health response in life cycle assessment using ED10s and DALYs: part 2--Noncancer effects.

In Part 1 of this article we developed an approach for the calculation of cancer effect measures for life cycle assessment (LCA). In this article, we propose and evaluate the method for the screening of noncancer toxicological health effects. This approach draws on the noncancer health risk assessment concept of benchmark dose, while noting important differences with regulatory applications in the objectives of an LCA study. We adopt the centraltendency estimate of the toxicological effect dose inducing a 10% response over background, ED10, to provide a consistent point of departure for default linear low-dose response estimates (betaED10). This explicit estimation of low-dose risks, while necessary in LCA, is in marked contrast to many traditional procedures for noncancer assessments. For pragmatic reasons, mechanistic thresholds and nonlinear low-dose response curves were not implemented in the presented framework. In essence, for the comparative needs of LCA, we propose that one initially screens alternative activities or products on the degree to which the associated chemical emissions erode their margins of exposure, which may or may not be manifested as increases in disease incidence. We illustrate the method here by deriving the betaED10 slope factors from bioassay data for 12 chemicals and outline some of the possibilities for extrapolation from other more readily available measures, such as the no observable adverse effect levels (NOAEL), avoiding uncertainty factors that lead to inconsistent degrees of conservatism from chemical to chemical. These extrapolations facilitated the initial calculation of slope factors for an additional 403 compounds; ranging from 10(-6) to 10(3) (risk per mg/kg-day dose). The potential consequences of the effects are taken into account in a preliminary approach by combining the betaED10 with the severity measure disability adjusted life years (DALY), providing a screening-level estimate of the potential consequences associated with exposures, integrated over time and space, to a given mass of chemical released into the environment for use in LCA.

Dose-Response Relationship, Drug↗
PubMed2002

Intake fraction for multimedia pollutants: a tool for life cycle analysis and comparative risk assessment.

We employ the intake fraction (iF) as an effective tool for expressing the source-to-intake relationship for pollutant emissions in life cycle analysis (LCA) or comparative risk assessment. Intake fraction is the fraction of chemical mass emitted into the environment that eventually passes into a member of the population through inhalation, ingestion, or dermal exposure. To date, this concept has been primarily applied to pollutants whose primary route of exposure is inhalation. Here we extend the use of iF to multimedia pollutants with multiple exposure pathways. We use a level III multimedia model to calculate iF for TCDD and compare the result to one calculated from measured levels of dioxin toxic equivalents in the environment. We calculate iF for emissions to air and surface water for 308 chemicals. We correlate the primary exposure route with the magnitudes of the octanol-water partition coefficient, Kow, and of the air-water partitioning coefficient (dimensionless Henry constant), Kaw. This results in value ranges of Kow and Kaw where the chemical exposure route can be classified with limited input data requirements as primarily inhalation, primarily ingestion, or multipathway. For the inhalation and ingestion dominant pollutants, we also define empirical relationships based on chemical properties for quantifying the intake fraction. The empirical relationships facilitate rapid evaluation of many chemicals in terms of the intake. By defining a theoretical upper limit for iF in a multimedia environment we find that iF calculations provide insight into the multimedia model algorithms and help identify unusual patterns of exposure and questionable exposure model results.

Algorithms↗
PubMed1982

Appearance and disappearance of tubular paracrystalline structures in somatotrophs and lactotrophs during the annual life cycle of the bat (Myotis lucifugus).

The fine structure of the endocrine (granulated) cells of the adenohypophysis of the bat was examined at different periods of the annual life cycle. During the active homeothermic period (early spring until late summer) the endocrine cells were heavily granulated, and evidence of granule release was commonly seen. At this time, but not at other times (hibernation and arousal), prominent paracrystalline structures were numerous and transiently appeared in the cytoplasm of acidophils (apparently both lactotrophs and somatotrophs) but not in the cytoplasm of basophils. These paracrystalline bodies were composed of densely packed, parallel arrays of tubules. The paracrystalline structures in lactotrophs differed in size, shape, and the pattern of arrangement of component tubules from those of somatotrophs. During hibernation no evidence of exocytosis was seen, and secretory granules accumulated in the cytoplasm. Prior to arousal, secretory granules were removed by autophagy.

Animals↗
PubMed1985

Morphohistochemical changes in hepatocytes during the life cycle of the European eel.

The comparative analysis of morphological, histochemical and cytochemical patterns of eel (Anguilla anguilla L.) hepatocytes reveals clear differences between two stages of its life cycle, i.e. the trophic stage (yellow eel) and reproductive stage (silver eel). The storage of glycogen prevails in the yellow eel, whilst lipids appear to be remarkably increased in the silver eel, in which some hepatocytes also show glycogen-rich areas. Generally, in the silver eel dehydrogenase and acid phosphatase activities seem greater and different distribution of the reaction products is present; on the contrary, a lower G6PDH activity is observed. The electron microscopy characteristics and distribution of both cellular organelles and reserve materials reflect the modifications found at light microscopy. The ultrastructural patterns provide further evidence for the heterogeneity of liver parenchyma in silver eel. In particular, the coexistence of nuclei showing a different degree of chromatin compactness is also accounted for by the quantitative cytochemical data on the nuclear DNA after Feulgen reaction and intercalation with propidium iodide at low and high concentrations. With regard to the DNA content, the hepatocytes in the silver eel as well as in the yellow eel are mainly 2c. However, some 4c values are also found, which according to the literature can be ascribed to cells in G2 phase. The present data may express the onset of different functional requirements during the reproductive stage in comparison with the trophic one. Moreover, our results are consistent with modifications found by other authors as a consequence of interruption of nourishment and during gonad maturation, i.e. two phenomena characterizing the transition from yellow to silver eel.

Acid Phosphatase↗
PubMed1992

Crossreactive antigens between life cycle stages of plasmodium falciparum.

The high mortality and morbidity induced by falciparum malaria has motivated research to find an efficient antimalarial vaccine. The parasite has a complex life cycle, both in the mosquito and human hosts, and presents a number of potential targets for vaccine-induced immune attack. Here, Inge Moelans and John Schoenmakers discuss how the search for protective antigens has been complicated by the discovery of multiple crossreactivities between different parasite proteins.

Journal Article↗
PubMed1987

Differential expression of heat-shock proteins and spontaneous synthesis of HSP70 during the life cycle of Blastocladiella emersonii.

The heat-shock response in Blastocladiella emersonii is dependent on the developmental stage. Cells exposed to elevated temperatures at different stages of the life cycle (sporulation, germination or growth) show a differential synthesis of heat-shock proteins (hsps). Of a total of 22 polypeptides induced, particular subsets of hsps appear in each phase, demonstrating a non-coordinate heat-shock gene expression. In contrast, heat-shock-related proteins (hsp76, hsp70, hsp39a) are spontaneously expressed at a high level during sporulation. By the criteria of two-dimensional gel electrophoresis and partial proteolysis mapping, the 70,000-Da protein, whose synthesis is induced spontaneously during sporulation, is indistinguishable from the heat-inducible hsp70. The techniques of in vitro translation, and Northern analysis using a Drosophila hsp70 probe, demonstrated that enhanced synthesis of hsp70, which occurs during heat-shock treatment and spontaneously during sporulation, is associated with an accumulation of hsp70 mRNA. These observations suggest that hsp70 gene expression is induced during sporulation.

Blastocladiella↗
PubMed2004

Environmental and human health impacts of growing genetically modified herbicide-tolerant sugar beet: a life-cycle assessment.

There is ongoing debate concerning the possible environmental and human health impacts of growing genetically modified (GM) crops. Here, we report the results of a life-cycle assessment (LCA) comparing the environmental and human health impacts of conventional sugar beet growing regimes in the UK and Germany with those that might be expected if GM herbicide-tolerant (to glyphosate) sugar beet is commercialized. The results presented for a number of environmental and human health impact categories suggest that growing the GM herbicide-tolerant crop would be less harmful to the environment and human health than growing the conventional crop, largely due to lower emissions from herbicide manufacture, transport and field operations. Emissions contributing to negative environmental impacts, such as global warming, ozone depletion, ecotoxicity of water and acidification and nutrification of soil and water, were much lower for the herbicide-tolerant crop than for the conventional crop. Emissions contributing to summer smog, toxic particulate matter and carcinogenicity, which have negative human health impacts, were also substantially lower for the herbicide-tolerant crop. The environmental and human health impacts of growing GM crops need to be assessed on a case-by-case basis using a holistic approach. LCA is a valuable technique for helping to undertake such assessments.

Journal Article↗
PubMed2005

Home transport and wastage: environmentally relevant household activities in the life cycle of food.

In environmental systems analysis of food production systems, the consumer phase (home transport, cooking, storing, and wastage) is an important contributor to the total life-cycle environmental impact. However, households are the least investigated part of the food chain. Information gathering about households involves difficulties; the number of households is large, and food-related activities are embedded in other household activities. In cooperation between researchers from environmental systems analysis and consumer research, Swedish households were surveyed by questionnaire, diary, and interviews. Data on home transport of food and wastage were collected. The average weekly driving distance was 28 to 63 km per household, depending on how trips made in conjunction with other errands are allocated. The wastage of prepared food ranged between 0 and 34% for different food categories, and wastage from storing between 0 and 164% (more food was discarded, e.g. by cleaning out a cupboard, than consumed). In both cases dairy products scored highest.

Activities of Daily Living↗
PubMed1991

Simulated effects of reproductive performance on life-cycle efficiency of lamb and wool production at three lambing intervals.

A deterministic computer model of a purebreeding sheep production system was used to simulate effects on life-cycle efficiency from genetic changes in lambing rate (LB), fertility (FERT), precocity of fertility (PREC), and estrus season length (ES) under annual (Y), 4-mo (A), and 73-d (S) breeding intervals. Ewes and lambs of a 1,000-ewe flock were fed to requirement through five yr, beginning with ewe lambs at the optimal breeding season and accumulating feed input (TDN) and market lamb equivalent weight of output (EBW), including cull ewes and wool. For annual lambing, improvement in cost (TDN/EBW equivalence) per 10% increase in genetic potential was -9.8, -8.2, -1.3, and -.8% for LB, FERT, PREC, and ES, respectively. For the A and S lambing intervals, corresponding gains in TDN efficiency were -19 for FERT and -9% for LB when ES was 72 d, but only -6 and -5% when ES was 192 d. Increasing PREC by 10% improved cost -3% under accelerated systems when ES was 72 d, but less than -1% when ES was 192 d. Cost reduction from 10% longer ES under A and S breeding intervals was greater when other reproductive performance was low (-11 and -17%) rather than high (-2 and -3%). Reduction in costs for A and S vs Y lambing intervals was greatest with long ES and was greater with low (-43 and -53%) than with high reproductive performance (-20 and -24%). When ES was 72 d, A and S intervals would reduce costs for high (-9 and -11%) but increase costs for low reproductive traits. Corresponding increases in CP/TDN required in diet would reduce gains in TDN/EBW only slightly. These results should aid in development of optimum selection criteria for stocks used for pure or rotation crossbreeding or as maternal parents of terminal crosses.

Animal Husbandry↗
PubMed1989

Self-reports of differentiation of self and marital compatibility as related to family functioning in the third and fourth stages of the family life cycle.

Using Bowen's, Olson's, and general systems frameworks, this investigator tested relationships among individual, marital, and family functioning in the stressed childrearing stages of the family life cycle. Sixty volunteer married couples completed the Level of Differentiation of Self Scale (LDSS), Locke-Wallace Marital Adjustment Test (MAT), and Family Adaptability and Cohesion Evaluation Scales (FACES) III. A significant canonical correlation was found among differentiation of self and marital compatibility as they both relate to family functioning. Subsequent canonical correlations were significant for wives but not for husbands, indicating gender differences in relationships among perceived individual, marital, and family phenomena. The concept of adaptability as proposed by Olson's Circumplex Model of Marital and Family Functioning was not supported. A revised model is proposed.

Adaptation, Psychological↗
PubMed1980

Morphogenesis of the plastidome and the flagellar apparatus during the vegetative life cycle of the colourless phytoflagellate Polytoma papillatum.

Serial-section reconstructions were used to study changes in morphology of the leucoplast and of flagellar apparatus during the vegetative life cycle of Polytoma papillatum. During interphase growth the volume of highly perforated leucoplast nearly doubled. The leucoplast of late interphase cells still had a deep cup shape (cyathiform), but several structural modifications were observed compared to the leucoplast of young interphase cells: either a thin and less perforated sheet-like area, taking up ca 25% of the external surface, and several double-layered areas occur sporadically at the tube-shaped part of the cup, or a bladder-shaped structure consisting of several very thin concentrically ringed layers occurred at the base of the tube. During preprophase the cyathiform leucoplast was transformed into a massive bowl-shaped (= poculiform) leucoplast, which was also characterized by thin-layered bladder-like or concentrically-ringed structures and by duplications in the form of pockets or chambers. The bipartition of the poculiform leucoplast occurred by furrowing, which started at preprophase and was completed only at the end of cytokinesis. The dynamics of the processes involved in these configural changes are discussed. During preprophase of the first division cycle the flagellar apparatus was subjected to several changes. The apical papilla which gave rise to the flagella was tied off into small 'extracytoplasmic' vesicles. This event caused a change in the orientation of the flagella to one another; the angle of ca 140 degrees during interphase was reduced to ca 90 degrees. The basal bodies detached from their axonemes and both the striated connection and the roots disintegrated. During prophase of the second division cycle the separation of the four basal bodies into two pairs and their migration towards the poles of the nucleus was completed; the outgrowth of the new daughter flagella also started. During late cytokinesis of the second division cycle the basal bodies had already duplicated and resynthesis of the striated connection was completed, whereas resynthesis of the roots was still in progress. The results are compared with those obtained from investigation of other algae.

Animals↗
PubMed1994

The relationship between retirement life cycle changes and older men's labor force participation rates.

This study probes the utility of older men's labor force participation rates (LFPRs) as indicators of the work-to-retirement transition. Specific attention is directed at how shifts in the retirement life cycle are related to LFPRs. Based on Current Population Survey data for the 1970s, a life table modeling approach showed that LFPRs are relatively weak indicators of the work-to-retirement transition. This was demonstrated by the relative stability in older men's age profiles of LFPRs despite significant changes in the timing and "organization" of the work-to-retirement transition. The 1970s evidenced a contraction of the main career and the expansion of both post-retirement work activity and retirement, yet none of these changes substantially altered the age profiles of older men's labor force participation rates.

Aged↗
PubMed1986

Life cycle and loss--the spiritual vacuum of heroin addiction.

This research studied the function of heroin addiction as a family-learned method of coping with death, separation, and loss across the life cycle. Heroin addicts, psychiatric outpatients, and normal students were given an extensive interview and test battery to determine the incidence of loss of family members and significant others. Because the impact of death is often overcome through religious rituals, this study also investigated the subjects' perception of their families' religious values and orientation to life's meaning and purpose. Results indicate that the incidence of death differs significantly across groups and that addicts have a distinct orientation to death, are more suicidal, and have more premature and bizarre death experiences. During childhood they have more family separations, and they tend to develop a distinct pattern of continuously separating from and returning to their families. They are also less likely to have a clearly defined purpose in life. A subset of parents from each group were also interviewed and tested, and these results support the theory of the intergenerational transmission of behavior.

Adaptation, Psychological↗
PubMed1987

The titre of juvenile hormone during the pupal and adult stages of the life cycle of Drosophila melanogaster.

Using combined gas chromatography/selected-ion mass spectroscopy, the titer of juvenile hormone was determined for whole-body extracts at various morphologically defined stages of the life cycle of Drosophila melanogaster. Only juvenile hormone III (JH-III) was detected. JH-III is present in early metamorphosis but by mid-metamorphosis it is below the level of detection (0.05 pmol/g). It then increases as the pharate adult matures and rises dramatically, beginning just prior to eclosion and reaching 5-7 pmol/g shortly after eclosion. The titer then begins to fall again as the adults mature in both males and females, though the decrease is more rapid in females. Preliminary studies show that low levels of JH-III are present during all the larval instars but are absent from eggs.

Animals↗
PubMedDate not supplied

[The tegument of Euzetrema knoepffleri, endoparasitic Monogenean of an amphibian: ultrastructure and evolution during the life cycle (author's transl)].

Euzetrema knoepffleri is an endoparasitic monogenean from the bladder of an Amphibian. Ultrastructural studies of the integument are made during the three stages of the life cycle: oncomiracidium, renal post-larva and adult. The meaning of the structures is discussed during the larval evolution to the adult and is compared with that of other monogeneans. The transition from fresh water to an urinary environment is in relation with the folding of the internal cytoplasmic membrane. This adaptation is specialized in water and ion transport through the integument, necessary for for the osmotic readjustment of the parasite: It has been noted that the tegument integrates ultrastructural adaptations to the biotope, independent of the phylogeny.

Amphibians↗
PubMed1988

The ultrastructure of prolactin cells in the annual cyprinodont Cynolebias whitei during its life cycle. A morphometric study in freshwater- and saltwater-reared fish.

Prolactin (PRL) cells were studied electron-microscopically and morphometrically in the annual cyprinodont fish, Cynolebias whitei during its life cycle. In prehatching larvae, PRL cells possessed small secretory granules, giant mitochondria and a well-developed Golgi apparatus. During hatching, no changes were observed in the volume density of the secretory granules, indicating that no increased release of PRL occurs at hatching. A significant change in the composition of PRL cells, i.e., the volume densities per cytoplasm volume of the different organelles, occurred between one day and one week of age. Thereafter, only minor differences were observed between age groups, indicating that no major changes occur in PRL cell activity during the lifespan of C. whitei. However, the volume density per cell volume of the nucleus decreased steadily with age during the lifespan. A comparison of the PRL cells in young and adult fish reared in fresh water (FW) with siblings reared from hatching in diluted sea water (1/3 SW) did not reveal any differences with respect to the volume densities of the organelles, including the secretory granules. However, significant differences were observed with respect to the diameter, electron-dense content and affinity to anti-PRL serum of the secretory granules. These differences indicate that, despite the similar volumetric composition of the PRL cells, their secretory granules contain a substantially higher concentration of PRL in FW-reared fish than in 1/3 SW-reared fish.

Aging↗