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1.
Ecology is being introduced to Evolutionary Developmental Biology to enhance organism-, population-, species-, and higher-taxon-level studies. This exciting, bourgeoning troika will revolutionise how investigators consider relationships among environment, ontogeny, and phylogeny. Features are studied (and even defined) differently in ecology, development, and evolution. Form is central to development and evolution but peripheral to ecology. Congruence (i.e., homology) is applied at different hierarchical levels in the three disciplines. Function is central to ecology but peripheral to development. Herein, the supercategories form (‘isomorphic’ or ‘allomorphic’), congruence (‘homologous’ or ‘homoplastic’), and function (‘adaptive’ or ‘nonadaptive’) are combined with two developmental mode (i.e., growth) categories (‘conformational’ or ‘nonconformational’) to provide a 16-class system for analysing features in studies in which ecology, development, and evolution are integrated.  相似文献   

2.
The river types in Wallonia (Belgium) were defined according to the system B of the European Water Framework Directive (WFD) taking into account obligatory and optional factors synthesized in three criteria: ‘size’, ‘slope’ and ‘natural region’. Under the hypothesis that benthic invertebrate assemblages would be specialized according to river type, a set of 627 faunal samples originating from an 11-year sampling period was tested to characterize river types with faunal assemblages. A multivariate approach led to gather 23 river types into seven groups exhibiting similar faunal assemblages. Using biocenotic metrics based on benthic invertebrate assemblages (e.g., the French standard IBGN), type-specific reference conditions and ecological status class limits were defined for each ‘natural’ river type group. Ecological potential was defined for heavily modified and for artificial (i.e., man-made canals) types. An ‘ecological status’ evaluation strategy was therefore developed and applied in the southern – and more natural – part of Wallonia, where many reference sites were available. In the northern part of Wallonia (i.e., the ‘Loess region’) where no high quality site was available, the expert judgement took a larger part in the definition of the reference conditions and of the ecological status class limits, in addition to the calculations. Two independent distribution gradients of taxa assemblages resulted from multivariate ordination: a first ‘saprobity axis’, as the taxa-sensitivity to organic contamination was increasing from ‘very resistant’ taxa (mainly located in the ‘Loess region’) to ‘sensitive’ and ‘very sensitive’ taxa (from the river types belonging to the Condroz, the Famenne, the Arden and the Jurassic regions) and a second axis characterizing the Meuse-specific faunal assemblage, gathering exotic species and typical limnophilous taxa of large heavily modified rivers. The ecological status monitoring management system developed in this study – i.e., the definition of faunal river type groups, related reference conditions and ecological status class limits – represents a proposal to be integrated in the ecological status assessment of biological elements for the implementation of the WFD and was tested in Wallonia. For the period 2000–2002 involving 349 different sites, the element ‘benthic invertebrate fauna’ was in that way classified ‘high status’ for 31.5% of sites, ‘good status’ for 31.5% and below ‘good status’ for 37% of sites. The best ecological status (i.e., 100% ‘high’ and ‘good’ status) was found in river type ‘Arden’s xenotrophic brooks with strong slope’ and in river types 8large rivers with medium slope’. The worst status was found in river types ‘Loess brooks and rivers with medium slope’.  相似文献   

3.
The powerful technology for transferring functional foreign genes into plants can only express its potential to the extent that our knowledge about signals and signal transmission in plants improves. In higher plants gene expression is regulated by ‘signals from within’ and ‘signals from without’ (e.g., light). Since light-mediated changes provide the basis for much of plant development, photocontrol of gene expression will mainly be considered. The recently discovered ‘plastidic factor’ will serve as the prototype of an intracellular ‘signal from within’. Particular emphasis will be laid on rapid interorgan signal transmission since these novel observations suggest a revision of the presently held concepts about the means of communication within a plant. It will be concluded in the end that the prevailing views about the nature of plants underestimate the degree of sophistication actually exhibited by higher plants.  相似文献   

4.
Pyrolysis mass spectrometry (PyMS) is a rapid, simple, high-resolution analytical method based on thermal degradation of complex materials in a vacuum. It is widely applied to the discrimination of closely related microbial strains. Leaf samples from eight cultivars (‘Apricot Delight’, ‘Cooler Grape’, ‘Cooler Peppermint’, ‘Equator Grape’, ‘Equator Rose’, ‘Equator White’, ‘Equator White Eye’, and ‘Little Bright Eye’) of Catharanthus roseus were subjected to PyMS for spectral fingerprinting. Discriminant analysis (DA) of PyMS data enabled us to assign these cultivars to discrete clusters. A hierarchical dendrogram based on DA provided a possible relationship among them that was in general agreement with a previously reported classification of the cultivars based on DNA fingerprints. Furthermore, those belonging to the same ‘series’ were grouped into a single cluster, which previously could not be achieved through similar approaches based on Fourier transform infrared spectroscopy or 1H NMR data. Overall results suggest that chemical differences (i.e., in pyrolysate composition) among cultivars, as detected by mass spectrometry, reflect their genetic variation.  相似文献   

5.
An earlier theory of cell differentiation and morphogenesis (Wassermann, 1972, 1973, 1978) is combined with the genetic control model of Davidson and Britten (e.g. 1979). The resulting new theory suggests how, bysystematic process algorithms, specifically enumerated combinations of batteries of structural genes can become switched on in particularly enumerated cells, via battery-specific enumerable regulator genes. The systematization is idealized. Up to a certain stage of development in each mitotically arising cell a unique cell-specific combination of structural genes called ‘marker genes’ is active. Marker genes are assumed to code for cell-specifying marker proteins (CSMPs) which permit cells carrying related markers to recognize each other, thus permitting specific cell sorting.Batteries of marker genes could ensure great developmental precision and can safeguard—via redundancies of CSMP types—against accidental loss or detrimental mutational modification of CSMPs or marker genes, respectively. This paper is much concerned with cell lineage in relation to ‘microdifferentiation’, where ‘microdifferentiation’ of a cell refers to a cell's active marker genes and its syntheses of CSMPs. A drastic distinction is made between ‘microdifferentiation’ and ‘gross’ differentiation of a cell, where the same ‘gross’ differentiation may be shared by a large number of cells that could each be uniquely ‘microdifferentiated’. Typical ‘gross’ differentiation could manifest itself in tissue specificity, whereas, up to certain stages of development, all cells of the same gross differentiation type (say tissue specificity) could each be uniquely ‘microdifferentiated’. The theory also assumes that at certain stages of the developmental process some (or in some organisms all) of the previously uniquely specified cells could give rise to small (or occasionally large) clones of equispecified cells, some of which might form clusters that represent complete ‘morphogenetic fields’ Tentative implementation mechanisms are proposed which suggest how the theory could operate in molecular biological terms. In particular, CSMPs could endow cell surface membranes with a highly specific protein network, and an associated equally specific cell surface coat. It is suggested how these highly specified cell surface coats and other systems could provide an ‘extracellular guidance network’ which could help to direct cells to attain energetically optimal locations relative to each other based on the matching of their surface specificities. In numerous experimental situations, where normally present optimal matching of cells is excluded, ‘alternative matching’ based on experiment-specific suboptimal matching could explain many data, notably in experimental development neurobiology (Wassermann, 1978).  相似文献   

6.
‘Hass’ is the most popular avocado (Persea americana Mill.) cultivar in the world. It has been characterized as a crop requiring cross-pollination. However, the potential extent of self-pollination and the most effective pollen donors (best cross-pollinizing cultivars) have not been determined. In this study, 56 markers were screened against ‘Hass’ and nine commonly used pollinizing cultivars grown in southern California: ‘Bacon,’ ‘Ettinger,’ ‘Fuerte,’ ‘Harvest,’ ‘Lamb Hass,’ ‘Marvel,’ ‘Nobel,’ ‘Sir Prize,’ and ‘Zutano.’ Seventeen microsatellite, i.e., simple sequence repeat (SSR) markers, were found to be very promising for paternity analysis. Four highly informative SSR markers were selected to accurately and unequivocally identify pollen parents of ‘Hass’ fruit from an orchard interplanted with these pollinizing cultivars. From 2003 to 2006, 7,984 ‘Hass’ fruit were analyzed for their paternity. Overall, the pollen parents of 99.55% of the analyzed fruit could be unequivocally identified with a single multiplex polymerase chain reaction (PCR). Only 36 fruits (<0.45%) required a second PCR reaction to reach unequivocal identification of the pollen parents.  相似文献   

7.
Four new and one unidentified species of Neohaliotrema Yamaguti, 1965 were obtained from the gills of the Indo-Pacific sergeant Abudefduf vaigensis (Quoy & Gaimard) off Pulau Langkawi, Malaysia. The five species, N. malayense n. sp., N. bombini n. sp., N. andamanense n. sp., N. parvum n. sp. and an unidentified Neohaliotrema sp. (similar to N. macracanthum Zhukov, 1976), are described and distinguished based mainly on features of the haptor. Species of this genus are divisible into two groups, the ‘maomao group’, with two pairs of morphometrically modified ‘marginal’ hooks and a fenestrated haptor, and the ‘gracile group’, with morphologically similar marginal hooks and an entire haptor. With the exception of N. bombini n. sp., the species described fit within the ‘maomao group’. It is suggested that the more complex Neohaliotrema species of the ‘maomao group’ have modified hooks 1 and 2 on a haptoral ‘isthmus’ between two large apertures, i.e. ‘windows’, whereas the less complex species lacking these features are those of the ‘gracile group’. Neohaliotrema spp. have only a single pair of pigmented eye-spots. A fenestrated haptor is unique to the Neohaliotrema spp. of the ‘maomao group’. The generic diagnosis of Neohaliotrema is amended to include new data and a key to its known species is presented.  相似文献   

8.
Most temperate-zone birds live in environments with a regular seasonality, and primarily use the long-term changes in photoperiod as a cue to initiate gonadal development in anticipation of the breeding season. Short-term cues such as food and temperature are later used to fine-tune the rate of gonadal development to local conditions. Many tropical habitats are seasonal, but the timing of the seasons (e.g., rainy season) can vary considerably between years. We hypothesize that to time breeding in environments with seasonal variability, tropical birds respond to both long-term and short-term environmental cues to initiate gonadal growth. We tested the effectiveness of photoperiod and food cues for the initiation of gonad growth in captive male spotted antbirds (Hylophylax n. naevioides) from Panama. A ‘control’ group was maintained on the short natural photoperiod of 12 h light and 12 h dark (LD 12:12) and adequate food. A ‘food-stimulated’ group was also held on LD 12:12 but received an increase in food quantity and quality. A ‘photo+food-stimulated’ group experienced an increase in daylength by 1 h (LD 13:11, the maximal photoperiod in Panama) and an increase in food quantity and quality. Within 3 weeks testis sizes of ‘food-stimulated’ birds increased significantly, suggesting that food cues alone can initiate gonad development. As expected from the previous experiment, testis sizes of ‘photo+food-stimulated’ birds, but not ‘control’ birds, also increased. We suggest that the capability to respond to both food and photoperiodic cues allows animal the flexibility to adjust reproductive activity to variable environmental conditions each year. Future work should elucidate whether food provides nutritional or non-nutritional cues, and the neurophysiological mechanisms by which food stimulates reproductive activity.  相似文献   

9.
The effects of six basal media on in vitro shoot proliferation of the greek grapevines Vitis vinifera L. cv. ‘Malagouzia’ and ‘Xinomavro’ were investigated. Galzy and Zlenco proved to be the most effective for ‘Malagouzia’ and ‘Xinomavro’, respectively. If only BA was present in the medium, shoot development was poor and the plantlets were chlorotic. When the medium was supplemented with BA and NAA, growth was enhanced. The best ratio (in μM) of growth regulators was 0.5/0.3 for ‘Malagouzia’, and 0.1/0.03 for ‘Xinomavro’, which resulted in the highest number of microshoots per explant and greatest proliferation rate. The development of ‘Malagouzia’ and ‘Xinomavro’ explants at 21±2 and 26±2°C was also investigated, revealing the higher temperature to be more effective. Regarding rooting, 0.5 μM IBA improved root formation at 26°C for ‘Malagouzia’ and 0.5 μM IBA at 21°C for ‘Xinomavro’. Moreover, 0.5 μM IBA resulted in a higher rooting percentage (>95%) and proved to be more beneficial for the overall morphological appearance of the plantlets of ‘Malagouzia’. After acclimatization, survival of microshoots cultivated in media with IBA was higher than those in NAA.  相似文献   

10.
Explaining the apparent non-random codon distribution and the nature and number of amino acids in the ‘standard’ genetic code remains a challenge, despite the various hypotheses so far proposed. In this paper we propose a simple new hypothesis for code evolution involving a progression from singlet to doublet to triplet codons with a reading mechanism that moves three bases each step. We suggest that triplet codons gradually evolved from two types of ambiguous doublet codons, those in which the first two bases of each three-base window were read (‘prefix’ codons) and those in which the last two bases of each window were read (‘suffix’ codons). This hypothesis explains multiple features of the genetic code such as the origin of the pattern of four-fold degenerate and two-fold degenerate triplet codons, the origin of its error minimising properties, and why there are only 20 amino acids. Reviewing Editor: Dr. Laura Landweber An erratum to this article can be found at .  相似文献   

11.
The chrysanthemum cultivar ‘Yuhuajinhua’ has a creeping habit. The anatomy and distribution of amyloplasts within ‘Yuhuajinhua’ stems were compared to those typical of non-creeping cultivars. ‘Yuhuajinhua’ stems are similar to those of conventional cultivars; but except for the pith, the proportion of the various tissues present in the upper side of stems was higher than that in the lower side. Most of the amyloplasts lie in the centre of the endodermal cells of the ‘Yuhuajinhua’ stems, rather than at the bottom, as is typical for non-creeping cultivars. When ‘Yuhuajinhua’ plants were oriented horizontally and kept in the dark, the stems retained their original growth direction, and the endodermis amyloplasts sedimented according to the gravitational direction. The endodermis amyloplasts responded rapidly to gravistimulation. The content of IAA in the upper side of the ‘Yuhuajinhua’ stems was higher than that in the lower side, associated with the assymetric growth of the stems.  相似文献   

12.
13.
Three cultivars (cvs.) of Gladiolus hybridus Hort., namely ‘Her Majesty’, ‘Aldebaran’ and ‘Bright Eye’ were successfully micropropagated. The cultures were established using intact cormels or segments of cormels and inflorescence axes on Murashige and Skoog (1962; MS) medium. The response depended on media supplements; both callus formation or direct induction of shoot buds was observed. Shoot differentiation from callus could be obtained on MS medium containing 1.0 μM BA (6–benzyladenine) and 10.0 μM NAA (α-naphthalene acetic acid) in all three cultivars. The same could be achieved by giving a heat shock (HS; 50 °C, 1h) to callus cultures (in case of ‘Her Majesty’ and ‘Aldebaran’ only) maintained on the basal medium. In these two cultivars, high sucrose concentration (0.232, 0.290 or 0.348 M) also favoured growth and proliferation of shoot cultures on a plant growth regulator-free medium at 20 °C in comparison to the cultures kept at 25 °C. On the other hand, shoot cultures maintained on the basal medium at 25 °C containing normal (0.058 M, i.e., 2.0%, w/v) sucrose concentration responded similar to those maintained at 20 °C on a high sucrose medium; reduced response was observed on normal sucrose containing medium at 20 °C. Heat shock enhanced shoot proliferation in the cultures maintained on basal medium, but induced prolific rooting in shoot cultures, within 5 days of HS, on high sucrose (optimum 0.232 M) medium. While the number of roots increased at higher sucrose concentrations in the medium in case of cvs. ‘Her Majesty’ and ‘Aldebaran’, the same was found to be independent of sucrose concentration in cv. ‘Bright Eye’. Generally the rooted plants produced on high sucrose (0.232 M) medium in comparison to medium with normal sucrose concentration showed better survival (ca. 90% as against 40%) in the soil. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

14.
Two apple genetic linkage maps were constructed using amplified fragment length polymorphisms (AFLPs), simple sequence repeats (SSRs), random amplified polymorphic DNAs (RAPDs), and expressed sequence tag (EST)-derived markers in combination with a pseudo-testcross mapping strategy in which the cultivars ‘Ralls Janet’ and ‘Delicious’ were used as the respective seed parents. Mitsubakaido (Malus sieboldii) was used as the pollen parent for each of the segregating F1 populations. Expressed sequence tag data were obtained from the random sequencing of cDNA libraries constructed from in vitro cultured shoots and maturing fruits of cv ‘Fuji’, which is the offspring of a cross between ‘Ralls Janet’ and ‘Delicious’. In addition, a number of published gene sequences were used to develop markers for mapping. The ‘Ralls Janet’ map consisted of 346 markers (178 AFLPs, 95 RAPDs, 54 SSRs, 18 ESTs, and the S locus) in 17 linkage groups, with a total length of 1082 cM, while that of ‘Delicious’ comprised 300 markers (120 AFLPs, 81 RAPDs, 64 SSRs, 32 ESTs, and the S, Rf, and MdACS-1 loci) on 17 linkage groups spanning 1031 cM. These maps are amenable to comparisons with previously published maps of ‘Fiesta’ and ‘Discovery’ (Liebhard et al., Mol Breed 10:217–241, 2002; Liebhard et al., Theor Appl Genet 106:1497–1508, 2003a) because several of the SSRs (one to three markers per linkage group) were used in all of the maps. Distorted marker segregation was observed in three and two regions of the ‘Ralls Janet’ and ‘Delicious’ maps, respectively. These regions were localized in different parts of the genome from those in previously reported apple linkage maps. This marker distortion may be dependent on the combinations of cultivars used for map construction.  相似文献   

15.
The objective of this paper is the structural and narrative reconstruction of representations of ‘nature’, ‘wildlife’ and ‘landscape’, held by rural residents of the Dadia Forest Reserve. Data collection involved in-depth interviews. Employing a social representations’ approach, we recovered representational elements that are expected in the case of rural belief systems, such as negative dispositions towards wolves and foxes, as well as elements of an urban adherence, such as nature’s independence. Representational elements refer to visual aspects of the countryside, which seem compatible with the figurative nucleus of the rural idyll. Concerning ‘wildlife’, residents focused on vultures, which comprise the main tourist attraction of the reserve. Scientific knowledge adds to the complexity of the narrative schema, which corresponds to the representation of ‘wildlife’. Interviewees perceived the rural landscape as an interface between the natural and the human-conditioned environment. Our study shows that interviewees make no reference to environmental conservation or quality of life issues, as it could be expected according to relatively wide definitions of the term ‘environmentalism’. Environmental messages reinforced by ecotourism development seem to be recalled primarily in terms of their compatibility with the perceived economic benefit of local people. Despite ecotourism development, representational elements that diverge from a tourist version of ‘nature’, ‘wildlife’ and ‘landscape’ were not pronounced within rural belief-systems. Further interventions within the study area are needed, in order to address a variety of topics under the environmental conservation discourse and raise the environmental awareness of rural residents.  相似文献   

16.
In this paper, we propose a mathematical model of viral infection in pest control. As the viral infection induces host lysis which releases more virus into the environment, on the average ‘κ’ viruses per host, κ∈(1,∞), so the ‘virus replication parameter’ is chosen as the main parameter on which the dynamics of the infection depends. There exists a threshold value κ 0 beyond which the infection persists in the system. Still for increasing the value of κ, the endemic equilibrium bifurcates towards a periodic solution, which essentially indicates that the viral pesticide has a density-dependent ‘numerical response’ component to its action. Investigation also includes the dependence of the process on predation of natural enemy into the system. A concluding discussion with numerical simulation of the model is also presented.  相似文献   

17.
This contribution is aimed to give support to ‘bottom-up’ approaches to the minimal or early cell research project. Even if, from this perspective, the most simple living cell still seems very far away, the analysis of less complex, infrabiological cellular systems (some of which could be relatively soon implemented in the lab) probably holds the key, or one of the fundamental keys, to the problem of origins of life. On these lines, we propose a simulation model to study the transition from proto-metabolic ‘lipid’ cells to ‘lipid-peptide’ cells, as a critical step in which self-reproducing vesicles could develop into more functionalized supramolecular systems Presented at: International School of Complexity – 4th Course: Basic Questions on the Origins of Life; “Ettore Majorana” Foundation and Centre for Scientific Culture, Erice, Italy, 1–6 October 2006.  相似文献   

18.
The activities of sucrolytic enzymes viz. sucrose synthase and invertases were compared in developing pods of two genotypes of lentil differing in seed weight. Biomass accumulation of both the podwall and seed of ‘large’ genotype was higher during development as compared to the ‘small’ genotype. High activity of acid invertase together with prolonged activity of alkaline invertase in podwall of ‘large’ genotype may lead to longer cell division phase resulting in its larger size and biomass. Greater biomass of podwall could be responsible for providing more reserves for the developing seed hence determining its size. Higher alkaline invertase activity in ‘large’ seed from 15–20 DAF can be correlated to the sustained sucrolytic conditions for producing more cells required for its larger size. Increased levels of sucrose synthase in ‘large’ seed especially during maturation phase suggest the role of this enzyme in enhancing the seed sink strength.  相似文献   

19.
Topological patterns in the development and evolution of metazoa, from sponges to chordates, are considered by means of previously elaborated methodology, with the genus of the surface used as a topological invariant. By this means metazoan morphogenesis may be represented as topological modification(s) of the epithelial surfaces of an animal body. The animal body surface is an interface between an organism and its environment, and topological transformations of the body surface during metazoan development and evolution results in better distribution of flows to and from the external medium, regarded as the source of nutrients and oxygen and the sink of excreta, so ensuring greater metabolic intensity. In sponges and some Cnidaria, the increase of this genus up to high values and the shaping of topologically complicated fractal-like systems are evident. In most Bilateria, a stable topological pattern with a through digestive tube is formed, and the subsequent topological complications of other systems can also appear. The present paper provides a topological interpretation of some developmental events through the use of well-known mathematical concepts and theorems; the relationship between local and global orders in metazoan development, i.e., between local morphogenetic processes and integral developmental patterns, is established. Thus, this methodology reveals a “topological imperative”: A certain set of topological rules that constrains and directs biological morphogenesis.  相似文献   

20.
‘Benifuuki’, a tea (Camellia Sinensis L.) cultivar in Japan, is rich in anti-allergic epigallocatechin-3-O-(3-O-methyl) gallate (EGCG3″Me). ‘Benifuuki’ green tea and simultaneous addition of ginger extract remarkably suppressed cytokine (TNF-α and MIP-1α) secretion from mouse bone marrow-derived mast cells after antigen stimulation and, as expected, suppressed delay-type allergy. After drinking ‘benifuuki’ green tea containing 43.5 mg of EGCG and 8.5 mg of EGCG3″Me, the AUC (area under the drug concentration time curve; min μg/ml) of EGCG was 6.72 ± 2.87 and EGCG3″Me was 8.48 ± 2.54 in healthy human volunteers. Though the dose of EGCG was 5.1 times the dose of EGCG3″Me, the AUC of EGCG3″Me was higher than that of EGCG. A double blind clinical study on subjects with Japanese cedar pollinosis was carried out. At the 11th week after starting the study, in the most severe cedar pollen scattering period, symptoms, i.e., blowing the nose and itching eyes, were significantly relieved in the ‘benifuuki’ intake group compared with the placebo group, and blowing the nose, itching eyes and nasal symptom score, and at the 11th and 13th weeks, stuffy nose, throat pain and the nasal symptom medication score were significantly relieved in the ‘benifuuki’ containing ginger extract group compared with the placebo group. These results suggested that over one consecutive month, drinking ‘benifuuki’ green tea was useful to reduce some of the symptoms from Japanese cedar pollinosis, and did not affect any normal immune response in subjects with seasonal rhinitis, and the ginger extract enhanced the effect of ‘benifuuki’ green tea.  相似文献   

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