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1.
The idea of immunological surveillance against cancer has existed for nearly 100 years but as no conclusive evidence has yet
been published the importance of the cellular immune defense in the detection and removal of incipient or existing tumors
is still a hotly debated subject. However, in order to select a relevant immunotherapeutic strategy in the treatment of cancer,
a fundamental understanding of the basic immunologic conditions under which a tumor develops and exists is a prerequisite.
Therefore, a murine model was set up that we hoped would enable us to confirm or reject the theory of immunological surveillance.
A large panel of methylcholanthrene induced tumors was established in T-cell immunodeficient nude mice and congenic normal
mice to study the influence of the immune system on developing tumors. As nude mice developed tumors fastest and with the
highest incidence, we concluded that in this model the immune system constituted a ‘tumor-suppressive factor’ delaying and
sometimes abrogating tumor growth, i.e. performing immune surveillance. Immunogenicity of the tumors was assessed by transplantation
back to normal histocompatible mice. Tumors originating from the immunodeficient nude mice turned out to be far more immunogenic
than tumors from normal mice, resulting in a high rejection rate. CD8+cytotoxic T cells were found to be indispensable for
this rejection, leading to the conclusion that the cytotoxic T cells perform immune selection in normal mice, eliminating
immunogenic tumor cell variants in the incipient tumor.
In this review, we discuss the difficulties facing immunotherapy when conclusions are drawn from the presented observations
and hypotheses. 相似文献
2.
The purpose of this paper is to investigate the differential responses of flower opening to ethylene in two cut rose cultivars,
‘Samantha’, whose opening process is promoted, and ‘Kardinal’, whose opening process is inhibited by ethylene. Ethylene production
and 1-aminocyclopropane-1-carboxylate (ACC) synthase and oxidase activities were determined first. After ethylene treatment,
ethylene production, ACC synthase (ACS) and ACC oxidase (ACO) activities in petals increased and peaked at the earlier stage
(stage 3) in ‘Samantha’, and they were much more dramatically enhanced and peaked at the later stage (stage 4) in ‘Kardinal’
than control during vasing. cDNA fragments of three Rh-ACSs and one Rh-ACO genes were cloned and designated as Rh-ACS1, Rh-ACS2, Rh-ACS3 and Rh-ACO1 respectively. Northern blotting analysis revealed that, among three genes of ACS, ethylene-induced expression patterns of
Rh-ACS3 gene corresponded to ACS activity and ethylene production in both cultivars. A more dramatic accumulation of Rh-ACS3 mRNA was induced by ethylene in ‘Kardinal’ than that of ‘Samantha’. As an ethylene action inhibitor, STS at concentration
of 0.2 mmol/L generally inhibited the expression of Rh-ACSs and Rh-ACO in both cultivars, although it induced the expression of Rh-ACS3 transiently in ‘Kardinal’. Our results suggests that ‘Kardinal’ is more sensitive to ethylene than ‘Samantha’; and the changes
of Rh-ACS3 expression caused by ethylene might be related to the acceleration of flower opening in ‘Samantha’ and the inhibition in
‘Kardinal’. Additional results indicated that three Rh-ACSs genes were differentially associated with flower opening and senescence as well as wounding. 相似文献
3.
Zhentu Ying Thomas L. Davenport Taifang Zhang Raymond J. Schnell Cecile L. Tondo 《Plant Molecular Biology Reporter》2009,27(3):374-380
‘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
4.
Ewa Hanus-Fajerska Maria Lech Anna Pindel Kazimierz Miczyński 《Acta Physiologiae Plantarum》2000,22(3):317-324
Protocols elaborated with the objective of achieving valuable material for selection procedure of variants with virusresistance
traits in tomato genotypes are presented. Preliminary results are demonstrated in the domain of testing for variability in
somaclones obtained through indirect adventitous organogenesis initiated on leaf explants of cultivated tomato (Lycopersicon esculentum Mill.). Somaclones were grown in greenhouse conditions and variation of their symptoms upon infection with tomato mosaic
(ToMV) or cucumber mosaic (CMV) respectively was observed. Tests for resistance to the local isolates of the above cited viruses
were performed using enzyme linked immunosorbent assay and back inoculation onto diagnostic plants. Screening data are presented.
Desirable variants were selected from cultivars ‘Moneymaker’, ‘Potentat’ and ‘Rutgers’. Some of the ‘Moneymaker’ somaclones
exhibited increased tolerance to cucumber mosaic virus, a few seemed to be even fully resistant though most were susceptible
as donor plants. The most favourable somaclonal lines are actually further tested and monitored for changes in horticultural
characteristics. The described procedure of searching for resistance trait in specific pathogen-free (SPF) plants regenerated
from infected tissue looks promising and thus can serve as aid in attaining appropriate objectives of breeding programme.
Additionaly experiments were initiated to obtain somaclones from cultivars ‘Beta’, ‘Krakus’ and Stevens Rodade hybrid via
regeneration of isolated protoplasts. To this end the callus stage was obtained from all donors. 相似文献
5.
We investigated the immunological responses induced by human interferon β (IFNβ) gene transfer in human gliomas produced
in the brains of nude mice. A suspension of human glioma U251-SP cells was injected into the brains of nude mice. The IFNβ
gene was transferred by intratumoral injection with cationic liposomes or cationic liposomes associated with anti-glioma monoclonal
antibody (immunoliposomes). When intratumoral injection of liposomes or immunoliposomes containing the human IFNβ gene was
performed every second day for a total of six injections, starting 7 days after tumor transplantation, complete disappearance
of the tumor was observed in six of seven mice that had received liposomes and in all seven mice receiving immunoliposomes.
In addition, experimental gliomas injected with immunoliposomes were much smaller than those injected with ordinary liposomes
following delayed injections beginning 14 days after transplantation. An immunohistochemical study of the treated nude mouse
brains revealed a remarkable induction of natural killer (NK) cells expressing asialoGM1 antigen. To investigate the significance
of NK cells in the antitumor effect, we injected liposomes or immunoliposomes containing the human IFNβ gene into tumors in
nude mice depleted of NK cells by irradiation and anti-asialoGM1 antibody administration. The antitumor effect of the liposomes
or immunoliposomes was abolished. Subsequent subcutaneous glioma challenge of the nude mice after intracerebral tumor implantation
and gene transfer resulted in no subcutaneous tumor growth. These results suggest that the induction of NK cells is important
in the cytocidal effect of liposomes or immunoliposomes containing the human IFNβ gene upon experimental gliomas.
Received: 10 February 1998 / Accepted: 1 September 1998 相似文献
6.
Csaba Lantos Anikó Gémes Juhász György Somogyi Krisztina Ötvös Pál Vági Róbert Mihály Zoltán Kristóf Norbert Somogyi János Pauk 《Plant Cell, Tissue and Organ Culture》2009,97(3):285-293
The influence of the developmental stage of microspores on establishing isolated microspore cultures of three Hungarian (‘Szegedi
80’, ‘Szegedi 178’, and ‘Remény’) and three Spanish (‘Jeromin’, ‘Jariza’, and ‘Jaranda’) pepper genotypes was investigated.
Donor anthers containing 80% uninucleated and 20% binucleated microspores yielded the highest frequency of successful microspore
cultures. Co-cultures with wheat, line ‘CY-45’, ovaries exhibited enhanced frequency of embryoid production than those with
pepper ovaries. Differences in efficiency of isolated pepper microspore culture establishment were observed among different
pepper genotypes. Green plantlets were regenerated from microspore-derived embryoids, but some were exhibited abnormal growth
habits, such as leaf rosetting. A total of seven fertile microspore-derived plants were obtained, including three ‘Jariza’,
three ‘Jaranda’, and a single ‘Szegedi 80’ plant. 相似文献
7.
Peroxidase activity of red raspberry canes was dependent on the cultivar and influenced the subsequent lignification. After
inoculation with Didymella applanata, responsible for the spur blight cane disease, the activity of soluble cytoplasmic enzyme increased in the moderately resistant
‘Latham’ and susceptible ‘Malling Promise’, similarly for syringaldazine and guaiacol as hydrogen donors. Systemic induction
found in ‘Latham’ was recognized as a symptom of defence mechanism responsible for fungal restriction. Locally enhanced peroxidase
activity in the ‘M.Promise’ tissues was related to the local lignification and/or may be associated with the loss of cell
integrity caused by pathogen penetration. Pathogen-induced changes of cell wall peroxidases were similar in both cultivars
mentioned above. No influence of the infection was found in the high susceptible Zeva cultivar.
Using native-PAGE analysis and horizontal starch electrophoresis of soluble fraction five constitutive acidic isoperoxidases
were detected in ‘Latham’ and three in ‘M. Promise’. The infection process was accompanied by the appearance of two new anodic
isoforms. 相似文献
8.
Aleksandra Korzeniewska Katarzyna Niemirowicz-Szczytt 《Acta Physiologiae Plantarum》2000,22(3):235-238
Earliness is a crucial factor of tomato field production in Poland. A. Michalska and B. Kubicki (1978) conducted the first
investigations on tomato earliness at the Department of Plant Genetics and Breeding. The main conclusions from these studies
indicated that it was possible to obtain varieties earlier than ‘New Yorker’ as a result of transgression. The two new varieties
(‘Alfa’ and ‘Akord F1’) proved to be two weeks earlier than ‘New Yorker’. However, earliness was correlated with smaller fruit weight (30–40 g).
At the next stage of experiment some improvement was achieved both in the size of fruit (45 g for ‘Beta’ up to 70 g for ‘Alka’)
as well as colour intensity and good flavour. With the next few years fruit weight was still increased (up to 100 g for ‘Maskarena’)
and a higher level of firmness was obtained (mid firm fruits for ‘Maskarena’ and ‘Delta’). At present, the Polish Research
Centre for Cultivar Testing recommends our varieties ‘Betalux’, ‘Promyk’ and ‘Delta’ as standards. 相似文献
9.
Waltraud Böhm Reinhold Schirmbeck J. Reimann 《Cancer immunology, immunotherapy : CII》1997,44(4):230-238
We demonstrate in a murine model that targeting an anti-viral T cell response to a growing tumor facilitates priming of a
tumor-associated antigen (TAA)-specific, rejecting T cell response. Murine P815 mastocytoma cells grow aggressively in a syngeneic
host. Transfected P815/S cells (expressing the hepatitis B surface antigen, HBsAg) also grow as subcutaneous tumors, but occasional
‘spontaneous’ rejections after transient growth are observed. Growth of P815/S tumors (but not of P815 tumors) is efficiently
suppressed by a CD8+ cytotoxic T lymphocyte (CTL)-dependent immune mechanism in mice primed to HBsAg by DNA–immunization. In hosts immunized against
HBsAg by DNA vaccination, HBsAg-specific CTL are generated. This specific CTL reactivity was targeted to s.c.-growing P815
tumors by intra tumor injections of either HBsAg-encoding plasmid DNA or viable P815/S cells; this treatment led to tumor
rejection in 70–80% of the tumor-bearing animals. All rejecting animals showed a CD8+ CTL-dependent resistance to subsequent challenges by native, non-transfected P815 tumors. Targeting an established anti-viral
(‘strong’) CTL response to a growing tumor hence is an efficient strategy to facilitate priming of a rejecting CTL response
against (‘weak’) TAA in this system.
Received: 18 December 1996 / Accepted: 6 February 1997 相似文献
10.
Unopened leaves, petioles and fully opened leaves from micropropagation cultures of five Vitis rotundifolia Michx. varieties were cultured on induction medium to study their embryogenic response. Among the various explants tested,
the maximum number of varieties produced embryogenic cultures from unopened leaves followed by fully opened leaves and petioles.
Based on morphological differences, two types of embryogenic cultures were identified. Friable cultures typically arose as
proembryonic masses (PEM) on induction medium, whereas somatic embryo production without an intervening PEM stage was observed
in compact cultures. Of the five varieties tested, the highest frequency of embryogenic response was observed from fully opened
leaves of ‘Supreme’ and unopened leaves and petioles of ‘Delicious’. Attempts to initiate suspension cultures from varieties
resulted in proliferation and maintenance of ‘Alachua’ and ‘Carlos’ cultures in liquid medium for 16 weeks. Embryogenic potential
of varieties was studied on cultures growing on embryo development medium. The maximum number of cotyledonary stage somatic
embryos from 0.2 g proembryonic masses were observed in ‘Carlos’ (379.3) followed by ‘Alachua’ (350.0) and ‘Delicious’ (305.0).
Cotyledonary stage somatic embryos germinated when cultured on Murashige and Skoog medium containing 1 μM Benzyladenine (BA).
Although high embryo germination rates (80–100%) were observed in the varieties tested, plant recovery from germinated somatic
embryos ranged from 6–47%. Embryogenic cultures could be maintained on X6 medium and used in genetic engineering studies. 相似文献
11.
Mahin Khatami 《Cell biochemistry and biophysics》2009,55(2):55-79
Acute inflammation is a highly regulated defense mechanism of immune system possessing two well-balanced and biologically
opposing arms termed apoptosis (‘Yin’) and wound healing (‘Yang’) processes. Unresolved or chronic inflammation (oxidative
stress) is perhaps the loss of balance between ‘Yin’ and ‘Yang’ that would induce co-expression of exaggerated or ‘mismatched’
apoptotic and wound healing factors in the microenvironment of tissues (‘immune meltdown’). Unresolved inflammation could
initiate the genesis of many age-associated chronic illnesses such as autoimmune and neurodegenerative diseases or tumors/cancers.
In this perspective ‘birds’ eye’ view of major interrelated co-morbidity risk factors that participate in biological shifts
of growth-arresting (‘tumoricidal’) or growth-promoting (‘tumorigenic’) properties of immune cells and the genesis of chronic
inflammatory diseases and cancer will be discussed. Persistent inflammation is perhaps a common denominator in the genesis
of nearly all age-associated health problems or cancer. Future challenging opportunities for diagnosis, prevention, and/or
therapy of chronic illnesses will require an integrated understanding and identification of developmental phases of inflammation-induced
immune dysfunction and age-associated hormonal and physiological readjustments of organ systems. Designing suitable cohort
studies to establish the oxido-redox status of adults may prove to be an effective strategy in assessing individual’s health
toward developing personal medicine for healthy aging. 相似文献
12.
Response of strawberry to inoculation with arbuscular mycorrhizal fungi under very high soil phosphorus conditions 总被引:1,自引:0,他引:1
A field study was done to assess the potential benefit of arbuscular mycorrhizal (AM) inoculation of elite strawberry plants
on plant multiplication, under typical strawberry nursery conditions and, in particular, high soil P fertility (Mehlich-3
extractible P=498 mg kg−1). Commercially in vitro propagated elite plants of five cultivars (‘Chambly,’ ‘Glooscap,’ ‘Joliette,’ ‘Kent,’ and ‘Sweet
Charlie’) were transplanted in noninoculated growth substrate or in substrate inoculated with Glomus intraradices or with a mixture of species (G. intraradices, Glomus mosseae, and Glomus etunicatum) at the acclimation stage and were grown for 6 weeks before transplantation in the field. We found that AM fungi can impact
on plant productivity in a soil classified as excessively rich in P. Inoculated mother plants produced about 25% fewer daughter
plants than the control in Chambly (P=0.03), and Glooscap produced about 50% more (P=0.008) daughter plants when inoculated with G. intraradices, while the productivity of other cultivars was not significantly decreased. Daughter plant shoot mass was not affected by
treatments, but their roots had lower, higher, or similar mass, depending on the cultivar–inoculum combination. Root mass
was unrelated to plant number. The average level of AM colonization of daughter plants produced by noninoculated mother plants
did not exceed 2%, whereas plants produced from inoculated mothers had over 10% of their root length colonized 7 weeks after
transplantation of mother plants and ∼6% after 14 weeks (harvest), suggesting that the AM fungi brought into the field by
inoculated mother plants had established and spread up to the daughter plants. The host or nonhost nature of the crop species
preceding strawberry plant production (barley or buckwheat) had no effect on soil mycorrhizal potential, on mother plant productivity,
or on daughter plant mycorrhizal development. Thus, in soil excessively rich in P, inoculation may be the only option for
management of the symbiosis. 相似文献
13.
Hoy Taek Kim Gen Hattori Yutaka Hirata Dae Ill Kim Jeong Hwan Hwang Yong Uk Shin Ill Sup Nou 《Journal of Plant Biology》2006,49(6):448-454
To prevent self-fertilization, apple has a gametophytic self-incompatibility mechanism, part of a widespread intraspecific
system, that is controlled by a multi-allelic locus. This attribute has been exploited in breeding programs for new cultivars.
Likewise, many apple orchards depend on artificial pollination. Therefore, molecular analysis and early identification of
the self-incompatibility (S) genotype could greatly improve breeding schemes and pollen donors selection. Here, we PCR-amplified
the S-RNase PCR fragments from a total of 14 cultivars and parents, using new primers (ASPF3+ASPR3) common to 23 S-alleles
in apple. The S-genotypes were determined for the following: ‘Hongro’ (S1S3), ‘Gamhong’ (S1S9), ‘Saenara’ (S1S3), ‘Chukwang’ (S3S9), ‘Hwahong’ (S3S9), ‘Seokwang’ (S3S3), ‘Hwarang’ (S1S9), ‘Sunhong’ (S3S9), ‘S.E.B.’ (S1S19), ‘S.G.D.’ (S2S3), and ‘Mollie’s Delicious’ (S3S7). We also confirmed the characteristics of the S-genotypes for eight Korean apple cultivars by PCR-Southern blot analysis,
using seven S-RNases as probes. 相似文献
14.
Shirasawa S Endo T Nakagomi K Yamaguchi M Nishio T 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2012,124(5):937-946
Low temperature at the booting stage of rice causes male sterility resulting in severe yield loss. Cold tolerance has long
been an important objective in rice breeding. We identified a quantitative trait locus (QTL) for cold tolerance on the long
arm of chromosome 3 from the cold-tolerant breeding line ‘Ukei 840’ by using F2 and BC1F2 populations from crosses between ‘Ukei 840’ and ‘Hitomebore’. The cold tolerance of ‘Ukei 840’ is derived from the Chinese
cultivar ‘Lijiangxintuanheigu’. The effect of this QTL on cold tolerance was confirmed by developing ‘Hitomebore’ chromosome
segment substitution lines having ‘Lijiangxintuanheigu’ alleles on chromosome 3. By producing recombinants in chromosome 3,
the QTL region for cold tolerance was delimited to the region of about 1.2-Mb region between RM3719 and RM7000. All lines
heterozygous for the QTL showed seed fertilities as low as that of ‘Hitomebore’, suggesting that the ‘Lijiangxintuanheigu’
allele for cold tolerance in the QTL region is recessive. Determination of a 1.2-Mb nucleotide sequence of ‘Ukei 840’ and
comparison with the published genomic sequence of ‘Nipponbare’ showed 254 SNPs, of which 11 were in coding regions of genes,
seven in five genes being non-synonymous. SNPs were detected in the 5-kb upstream regions of 89 genes, but no differences
of gene expression levels were detected between alleles of these genes. Although further delimitation is required to identify
the gene responsible for cold tolerance of ‘Lijiangxintuanheigu’, SNP markers developed here will be useful for marker-assisted
selection in a breeding program using ‘Lijiangxintuanheigu’ as a donor of cold tolerance. 相似文献
15.
Adventitious shoot regeneration from leaf explants of southern highbush blueberry cultivars 总被引:1,自引:0,他引:1
Cheng Liu Pete Callow Lisa J. Rowland James F. Hancock Guo-qing Song 《Plant Cell, Tissue and Organ Culture》2010,103(1):137-144
Protocols were developed to optimize adventitious shoot regeneration from four southern highbush blueberry cultivars. Leaf
explants from 6 week-old shoots of the four cultivars were excised and cultured on woody plant medium each containing thidiazuron
(4.54 or 9.08 μM), zeatin (18.2 μM), or zeatin riboside (5.7 or 11.4 μM) either separately or in combination with α-naphthaleneacetic
acid at 2.69 μM. Optimum medium for shoot regeneration was genotype-dependent. Efficient regeneration was obtained at frequencies
of 88.9% for ‘Jewel’, 87.8% for ‘Emerald’, 53.3% for ‘Jubilee’ and 87.8% for ‘Biloxi’. Leaf explants of newly developed shoots
from the cultures having undergone five subcultures had higher regeneration frequencies than those having undergone two subcultures.
Regenerated shoots, 80–100% for each cultivar, rooted in 8 weeks after transplantation to soil. The regeneration systems described
have potential use in genetic transformation of southern highbush blueberry cultivars. 相似文献
16.
Different hypotheses on the genetic control of the resistance to the plum pox virus (PPV) have been reported in apricot, but
there was a lack of agreement about the number of loci involved. In recent years, apricot genetic maps have been constructed
from progenies derived from ‘Stark Early Orange’ or ‘Goldrich’, two main sources of resistance, three of these including the
mapping of the PPV resistance loci. As the location of the locus was not precisely established, we mapped the PPV resistance
loci using interval mapping (IM), composite interval mapping (CIM), and the Kruskal–Wallis non-parametric test in the F1 progeny derived from a cross between the susceptible cv. ‘Polonais’ and ’Stark Early Orange’. Four genomic regions were identified
as being involved in PPV resistance. One of these mapped to the upper region of linkage group 1 of ‘Stark Early Orange’, and
accounted for 56% of the phenotypic variation. Its location was similar to the one previously identified in ‘Goldrich’ and
Prunus davidiana. In addition, a gene strongly associated to these major quantitative trait loci (QTL) was found to be related to PPV infection.
Two putative QTLs were detected on linkage groups 3 of ‘Polonais’ and 5 of both ‘Polonais’ and ‘Stark Early Orange’ with both
parametric and non-parametric methods at logarithm of odds (LOD) scores slightly above the detection threshold. The last QTL
was only detected in the early stage of the infection. PPV resistance is, thus, controlled by a major dominant factor located
on linkage group 1. The hypothesis of recessive factors with lower effect is discussed. 相似文献
17.
Experiments were conducted to quantify parasitism of Colorado potato beetle,Leptinotarsa decemlineata (Say), by the egg parasitoid,Edovum puttleri Grissell, on 3 different cultivars of eggplant,Solanum melongena L. Levels of parasitism were higher (P<0.05) on ‘Black Pride’ than on other cultivars. The percentage of egg masses that
were parasitized was 1.2-fold higher (P<0.05) on ‘Black Pride’ than on ‘Harris Special’ and ‘White’. The number of eggs per
mass that were parasitized was 1.3- and 1.4- fold greater (P<0.05) on ‘Black Pride’ than on ‘Harris Special’ and ‘White’,
respectively. The percentage of eggs that were parasitized per mass and percentage of emerged adult parasitoids did not differ
(P>0.05) among cultivars; between 2.1- to 2.6- fold more females than males emerged from eggs on all cultivars during the
growing season.Edovum puttleri suppressed the 2nd generation ofL. decemlineata on ‘Black Pride’ and ‘Harris Special’, but did not suppress populations on ‘White’.
相似文献
18.
Matthew R. Gilligan 《Environmental Biology of Fishes》1980,5(2):109-116
Synopsis Reef fish community composition in three segments of a peninsular rocky shoreline in the Gulf of California was estimated
over four periods by visual observation. ‘Point’ and ‘bay’ segments had regular and distinct species compositions over most
periods while a ‘middle’ segment was least distinct but consistently had the greatest number of species. Compositional change
along the peninsula was least regular during the coldest sea temperature period (April). Mean species turnover between segments
was highest between point and bay. Within segments, the point had greater compositional predictable composition (lowest species
turnover). When species with regular frequency of encounter were classified into ‘point’, ‘middle’, ‘bay’, and ‘no trend’
groups it was found that comparatively more ‘point’ species had pelagic eggs and comparatively more ‘bay’ species had demersal
eggs. Beta diversity of rocky-shore fishes along the physical gradient of the Punta Doble peninsula reflects a transition
between exposed and protected rocky shoreline communities. The correlated physical environmental characteristics associated
with exposed and protected habitats are discussed in relation to diversity regulation and dispersal strategies in reef fishes. 相似文献
19.
Gérald Chouinard Stuart B. Hill Charles Vincent 《Entomologia Experimentalis et Applicata》1994,70(2):129-142
In the spring of 1987 and 1988,65Zn labeled plum curculios,Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), were released within two field cages, each containing four dwarf apple trees. The cages
were surveyed regularly between ‘pink’ and 22 d after ‘fruit set’ stages, and the location of labeled insects and substrates
occupied were recorded. Labeled beetles first appeared in trees between ‘pink’ stage and beginning of bloom, and the number
within trees gradually increased until ‘petal fall’ stage. Between ‘full bloom’ and 22 d after ‘fruit set’ stages, adults
were found on the ground in 54% of the observations. At ‘petal fall’ stage, the main host structures occupied were spurs,
twigs, and flowers or fruit. Height in the trees, rate of movement (cm/h), and occurrence on the ground, spurs, flowers or
fruits, and leaves and new annual growth, were related to the product of air temperature and relative humidity. Most dispersal
from tree to tree occurred between ‘full bloom’ and ‘fruit set’ stages. Highest occurrence in trees was observed between 1800
and 0000 h. In the daytime, labeled adults tended to leave host structures except spurs, which were used as resting sites,
mostly by females. Females occurred significantly higher in the tree canopy than males, although egg-laying was most frequent
at mid-level. During bloom, up to 30% of plum curculios were found to rest simultaneously at the base of tree trunks, prior
to their gradual invasion of trees. This behavior should be taken into account in the development of an effective shelter
trap for monitoring this insect, and in the design of integrated control strategies.
Résumé Au printemps de 1987 et 1988, des charan?ons de la pruneConotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae) adultes et marqués au65Zn ont été relachés dans 2 cages extérieures contenant chacune 4 pommiers nains. L'intérieur des cages a été ratissé régulièrement entre le stade ‘bouton rose’ et 22 jours après le stade ‘nouaison’ afin de déterminer la position et les micro-habitats des insectes marqués. La première présence d'adultes dans les arbres fut notée entre le stade ‘bouton rose’ et le début de la floraison, augmentant graduellement par la suite jusqu'au stade ‘calice’. Entre le stade ‘pleine floraison’ et 22 jours après le stade ‘nouaison’, les adultes ont été retrouvés au sol dans 54% des observations. Au stade ‘calice’, les adultes ont été retrouvés principalement sur les lambourdes, les petites branches, les fleurs et les fruits. La hauteur des charan?ons dans les arbres, leur taux de déplacement (cm/h), et leur présence sur le sol, les lambourdes, les fleurs ou fruits, les feuilles et les pousses de l'année ont tous été reliés au produit de la température et de l'humidité relative de l'air. La majorité des déplacements d'un arbre à l'autre fut observée entre les stades ‘pleine floraison’ et ‘nouaison’. La hauteur maximale dans les arbres fut atteinte entre 1800 et 0000 h. Durant le jour, les charan?ons ont montré une tendance à quitter les arbres, sauf pour plusieurs femelles qui ont préférer se réfugier à la base des lambourdes. Les femelles ont également été retrouvées significativement plus haut que les males et ont montré une préférence pour la strate intermédiaire lors de la ponte. Durant la floraison, jusqu'à 30% des charan?ons furent retrouvés simultanément à la base du tronc des pommiers. Ce comportement pourrait être mis à profit pour développer un piège efficace pour le dépistage des adultes, et des stratégies de lutte plus écologiques.相似文献
20.
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