Epizootiological Studies of Amblyospora albifasciati (Microsporidiida: Amblyosporidae) in Natural Populations of Aedes albifasciatus (Diptera: Culicidae) and Mesocyclops annulatus (Copepoda: Cyclopidae) in a Transient Floodwater Habitat

2001 ◽  
Vol 77 (1) ◽  
pp. 68-74 ◽  
Author(s):  
Maria V Micieli ◽  
Juan J Garcia ◽  
Theodore G Andreadis
Keyword(s):  
Natural Populations ◽  
Aedes Albifasciatus

High-voltage electron microscopy of maxillary gland of spirochete-infected brine shrimp: lesion of efferent tubule

1988 ◽  
Vol 46 ◽  
pp. 362-363
Author(s):  
G. E. Tyson ◽  
M. J. Song
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Brine Shrimp ◽  
Natural Populations ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
Infected Adult

Natural populations of the brine shrimp, Artemia, may possess spirochete- infected animals in low numbers. The ultrastructure of Artemia's spirochete has been described by conventional transmission electron microscopy. In infected shrimp, spirochetal cells were abundant in the blood and also occurred intra- and extracellularly in the three organs examined, i.e. the maxillary gland (segmental excretory organ), the integument, and certain muscles The efferent-tubule region of the maxillary gland possessed a distinctive lesion comprised of a group of spirochetes, together with numerous small vesicles, situated in a cave-like indentation of the base of the tubule epithelium. in some instances the basal lamina at a lesion site was clearly discontinuous. High-voltage electron microscopy has now been used to study lesions of the efferent tubule, with the aim of understanding better their three-dimensional structure.Tissue from one maxillary gland of an infected, adult, female brine shrimp was used for HVEM study.

Effect of acid deposition on trichome morphology and dogwood anthracnose biology

1992 ◽  
Vol 50 (1) ◽  
pp. 840-841
Author(s):  
Kyle T. Thornham ◽  
R. Jay Stipes ◽  
Randolph L. Grayson
Keyword(s):  
Acid Deposition ◽  
Disease Incidence ◽  
Natural Populations ◽  
Tree Disease ◽  
Flowering Dogwood ◽  
Discula Destructiva ◽  
Disease Induction ◽  
Dogwood Anthracnose ◽  
Trichome Morphology ◽  
Precipitation Events

Dogwood anthracnose, caused by Discula destructiva (1), is another new catastrophic tree disease that has ravaged natural populations of the flowering dogwood (Cornus florida) in the Appalachians over the past 15 years, and the epidemic is prognosticated to continue (2). An estimated 9.5 million acres have been affected, primarily in the Appalachian Mountains, from VA southwards, alone, and an estimated 50% of all dogwoods in PA have been killed. Since acid deposition has been linked experimentally with disease induction, and since the disease incidence and severity are more pronounced at higher elevations where lower pH precipitation events occur, we investigated the effect of acidic foliar sprays on moiphologic changes in the foliar cuticle and trichomes (3), the initial sites of infection and foci of Discula sporulation.

Urbanization of fauna on the example of marsh frog (Pelophylax ridibundus)

2015 ◽  
Vol 26 (3-4) ◽  
pp. 116-123
Author(s):  
A. P. Korzh ◽  
T. V. Zahovalko
Keyword(s):  
Urban Areas ◽  
Cognitive Modeling ◽  
Negative Impact ◽  
Natural Populations ◽  
Cellular Level ◽  
Anthropogenic Factors ◽  
Migration Routes ◽  
Corrective Effect ◽  
The Impact ◽  
The City

Recently, the number of published works devoted to the processes of synanthropization of fauna, is growing like an avalanche, which indicates the extreme urgency of this theme. In our view, the process of forming devices to coexist with human and the results of his life reflects the general tandency of the modern nature evolution. Urbanization is characteristic for such a specific group of animals like amphibians, the evidence of which are numerous literature data. Many researchers use this group to assess the bioindicative quality of the environment. For this aim a variety of indicators are used: from the cellular level of life of organization up to the species composition of the group in different territories. At the same time, the interpretation of the results is not always comparable for different areas and often have significantly different interpretations by experts. Urban environment, primarily due to the contamination is extremely aggressive to amphibians. As a consequence, the urban populations of amphibians may be a change in the demographic structure, affecting the reproductive ability of the population, the disappearance of the most sensitive species or individuals, resizing animals, the appearance of abnormalities in the development, etc. At the same time play an important amphibians in the ecosystems of cities, and some species in these conditions even feel relatively comfortable. Therefore, it is interesting to understand the mechanisms of self-sustaining populations of amphibians in urban environments. To assess the impact of natural and anthropogenic factors on the development of amphibian populations were used cognitive modeling using the program Vensim PLE. Cognitive map of the model for urban and suburban habitat conditions were the same. The differences concerned the strength of connections between individual factors (migration, fertility, pollution) and their orientation. In general, factors like pollution, parasites, predators had negative impact on the population, reducing its number. The birth rate, food and migration contributed to raising number of individuals. Some of the factors affected on the strength to of each other as well: the majority of the factors affected the structure of the population, had an influence on the fertility. Thanks to it the model reflects the additive effect of complex of factors on the subsequent status of the population. Proposed and analyzed four scenarios differing strength and duration of exposure. In the first scenario, a one-time contamination occurs and not subsequently repeated. The second and third scenario assumes half board contamination, 1 year (2 scenario) and two years (scenario 3). In the fourth scenario, the pollution affected the population of amphibians constantly. In accordance with the results of simulation, much weaker than the natural populations respond to pollution - have them as an intensive population growth and its disappearance at constant pollution is slow. Changes to other parameters of the model showed that this pollution is the decisive factor -only the constant action leads to a lethal outcome for the populations. All other components of the model have a corrective effect on the population dynamics, without changing its underlying trand. In urban areas due to the heavy impact of pollution maintaining the population is only possible thanks to the migration process – the constant replenishment of diminishing micropopulations of natural reserves. This confirms the assumption that the form of existence metapopulations lake frog in the city. In order to maintain the number of amphibians in urban areas at a high level it is necessary to maintain existing migration routes and the creation of new ones. Insular nature of the placement of suitable habitats in urban areas causes the metapopulation structure of the types of urbanists. Therefore, the process of urbanization is much easier for those species whicht are capable of migration in conditions of city. In the initial stages of settling the city micropopulationis formed by selective mortality of the most susceptible individuals to adverse effects. In future, maintaining the categories of individuals is provided mainly due to migration processes metapopulisation form of the species of existence is supported). It should be noted that the changes in the previous levels are always saved in future. In the case of reorganizations of individuals we of morphology can assume the existence of extremely adverse environmental conditions that threaten the extinction of the micropopulations. 

Dwindling status of Epimedium Elatum (Morren & Decne) and its geographical distribution in Kashmir Himalaya, India

2018 ◽  
pp. 47-52
Keyword(s):  
Medicinal Plant ◽  
Biological Activities ◽  
Conservation Status ◽  
Natural Populations ◽  
Culture Techniques ◽  
Kashmir Himalayas ◽  
Near Future ◽  
First Time ◽  
Tissue Culture Techniques

Epimedium elatum (Morren & Decne) of family Berberidaceace is a rare perennial medicinal plant, endemic to high altitude forests of Northwestern Himalayas in India. Ethnobotanically, it has been used as an ingredient for treatment of bone-joint disorders, impotence and kidney disorders in Kashmir Himalayas. Phytochemically, it is rich in Epimedin ABC and Icariin; all of these have been demonstrated to possess remarkable biological activities like PDE-5 inhibition (treatment of erectile dysfunction), anticancer, antiosteoporosis antioxidant and antiviral properties. The present investigation reports its traditional usage, comprehensive distribution and conservation status from twenty ecogeographical regions in Kashmir Himalayas, India. The species was reported from Gurez valley for the first time. Numerous threats like excessive grazing, deforestration, habitat fragmentation, tourism encroachment, landslides and excessive exploitation have decreased its natural populations in most of the surveyed habitats. Consequently, its existence may become threatened in near future if timely conservation steps are not taken immediately by concerned stakeholders involved in medicinal plant research. Moreover, use of plant tissue culture techniques is recommended for development of its in vitro propagation protocols. Therefore, introduction of this medicinal plant in botanical gardens, protected sites and development of monitoring programmes are needed for its immediate conservation in Northwestern Himalayas, India.

Specific features of long-term domestication of australian crayfish Cherax quadricarinatus in conditions of the western part of Russian Federation

2018 ◽  
Vol 194 ◽  
pp. 188-192
Author(s):  
D. I. Shokasheva
Keyword(s):  
Natural Selection ◽  
Russian Federation ◽  
Natural Populations ◽  
Cherax Quadricarinatus ◽  
Local Environments ◽  
Local Species ◽  
Adaptive Ability

Natural populations of crayfish are in depression in Russia and local species are not cultivated. In this situation, experimental cultivation of allochtonous australian crayfish Cherax quadricarinatus is conducted. This species is distinguished by high reproductive abilities and good consumer properties. It has domesticated in Russia spontaneously and produced 9–10 generations in Astrakhan Region. Certain natural selection in the process of domestication provides adaptive ability of this species to local environments and its capabil­ity to reproduce a viable progeny, so there is no doubts in good prospects of its cultivation in industrial conditions.

On the diagnostics of Adonis L. species (Ranunculaceae) of the Russian flora

2020 ◽  
pp. 3-14
Author(s):  
Aleksandr Luferov
Keyword(s):  
Raw Materials ◽  
Natural Populations ◽  
Structural Features ◽  
Biologically Active ◽  
Scientific Medicine ◽  
Diagnostic Features ◽  
Plant Raw Materials ◽  
Similar Chemical ◽  
Chemical Studies ◽  
Alternative Sources

The article provides brief information about cardiotonic, sedative, cytostatic, diuretic, and antibacterial effects of biologically active compounds of Adonis L. (Ranunculaceae) species. Chemical studies allowed to identify the cardiac glycosides, or cardenolides: or cardenolides: adontoxin, adonitol, adonitoxigenin, acetyldigitoxin and others. In scientific medicine, it is currently allowed to use Adonis vernalis L. Other types of Adonis have a similar chemical composition and are offered as substitutes for this official species, for example, Adonis apennina L. Many Adonis species have limited natural resources, and in some regions are rare, requiring conservation of their natural populations. The search for alternative sources of medicinal plant raw materials, based on this, is relevant. The experimental part of our research was carried out using the morphological and geographical method with the involvement of information on ecology and phenology. For the first time summarizes the diagnostic features of Adonis flora of Russian flora. Previously unknown structural features (shape and size of anthers) were identified that characterize the subgenera Adonanthe and Adonis. Taxonomic study of the genus Adonis of the Russian flora allowed us to determine its species composition, clarify its systematic affiliation, and nomenclature synonyms. 9 species were identified. Of these, 6 are perennials belonging to the subgenus Adonanthe, section Consiligo, which includes 2 subsections: Amurenses (2 species) and Vernales, which is differentiated into 2 rows: Apenninae (2 species) and Vernales (2 species). Subgenus Adonis is represented by 2 sections: Adonis (1 species) and Lophocarpa with sections Aestivales (1 species) and Dentatae (1 species). For all the considered species and varieties, the main distribution areas are given. A key has been compiled to determine the wild Adonis species distributed in Russia.

Phenotypic and phenological behaviours of clones of three natural populations of Atriplex halimus L. grown in a common garden

2003 ◽  
Vol 29 (2) ◽  
pp. 179-188
Author(s):  
Abdelaziz Abbad ◽  
Abdelbasset El Hadrami ◽  
Abderrazzak Benchaabane
Keyword(s):  
Natural Populations ◽  
Common Garden ◽  
Atriplex Halimus
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