TRANSMISSION AND PATHOGENESIS OF CATTLE LEUKEMIA

1970 ◽  
pp. 44-47
Author(s):  
V. V. Makarov
Keyword(s):  
Latent Infection ◽  
Biological Species ◽  
Complete Loss ◽  
Acquired Immunity ◽  
Phenotypic Characters ◽  
Structure Morphology ◽  
The Status ◽  
Sporadic Cases ◽  
Proliferation Of Lymphocytes ◽  
Enzootic Bovine Leucosis

The reverse strategy of the genome of the enzootic bovine leucosis (EBL) virus and all retroviruses as pathogens represents the peak of the evolutionary perdection of parasitism with the preservation of their biological species at the level of only the genotype and the complete loss of trivial phenotypic characters (structure, morphology, reproduction). This explains many features of pathobiosis in leucosis, especially the malignant transformation of the host cell and the reproduction of the viral genome in the context of unlimited proliferation of lymphocytes, absolute immune evasion in relation to the antiviral protective effectors of both innate and acquired immunity, and intracellular transmission of the infection by the epizootic chain. The principal feature of EBL is clinical dimorphism, i.e. the status of latent infection an absolute quantitative and chronological predominance of the incubation period of the course, essentially a cryptic form of infection throughout a productive life of the animal, and the illness per se in a pathological sense, extremely rare sporadic cases of a manifest form of lymphosarcomatosis that arise and really recorded only in old animals, outside of productive age. In this article the transmission of infection and the pathogenesis of EBL are interpreted from modern parasitic systemic positions as aspects of this problem that are little being considered in the home publications.

scholarly journals Discovery of the nest of the yellow jacket Vespula structor (Smith) (Hymenoptera, Vespidae) from China with description of its immature stages

2018 ◽  
Vol 67 ◽  
pp. 103-120
Author(s):  
Qing-Qing Tan ◽  
Jiang-Li Tan ◽  
Ruo-Nan Zhang ◽  
Xiao-Xia Tian ◽  
Jian-Ke Jian
Keyword(s):  
Immature Stages ◽  
Nest Structure ◽  
Yellow Jacket ◽  
Structure Morphology ◽  
The Status ◽  
Taxonomic Studies ◽  
First Time

Data on the nest structure, morphology of all stages and behaviour have contributed to the phylogenetic and taxonomic studies of social vespids. Two underground nests of Vespulastructor (Hymenoptera, Vespidae, Vespinae) were discovered in China. For the first time, the morphology of all the stages, and the nests are described in detail and illustrated. It is additional evidence supporting the recent conclusion that synonymized Vespulagongshanensis with V.structor. The status of Vespulastructor within both the genus Vespula and the vulgaris-group are briefly discussed.

scholarly journals Nested biological variation and speciation

1998 ◽  
Vol 353 (1366) ◽  
pp. 207-218 ◽  
Author(s):  
Susan A. Foster ◽  
Robert J. Scott ◽  
William A. Cresko
Keyword(s):  
Population Differentiation ◽  
Gasterosteus Aculeatus ◽  
Biological Species ◽  
Population Variation ◽  
Population Characteristics ◽  
Secondary Contact ◽  
Speciation Process ◽  
Initial Stage ◽  
Hierarchical Levels ◽  
The Status

The modes of speciation that are thought to have contributed most to the generation of biodiversity require population differentiation as the initial stage in the speciation process. Consequently, a complete understanding of the mechanisms of speciation requires that the process be examined not just after speciation is complete, or nearly so, but also much earlier. Because reproductive isolation defines biological species, and it evolves slowly, study of the process may require a prohibitive span of time. Even if speciation could be observed directly, selection of populations in the process of speciation is typically difficult or impossible, because those that will ultimately undergo speciation cannot be distinguished from those that will differentiate but never assume the status of new biological species. One means of circumventing this problem is to study speciation in taxa comprising several sibling species, at least one of which exhibits extensive population differentiation. We illustrate this approach by exploring patterns of population variation in the post–glacial radiation of the threespine stickleback, Gasterosteus aculeatus . We focus on lacustrine populations and species within this complex, demonstrating parallel axes of divergence within populations, among populations and among species. The pattern that emerges is one of parallel relationships between phenotype and fitness at all three hierarchical levels, a pattern that facilitates exploration of the causes and consequences of speciation and secondary contact. A second outcome of this exploration is the observation that speciation can be the consequence of a cascade of effects, beginning with selection on trophic or other characteristics that in turn force the evolution of other population characteristics that precipitate speciation. Neither of these conclusions could have been reached without comparative studies of wild populations at several hierarchical levels, a conclusion reinforced by a brief survey of similar efforts to elucidate the process of speciation. We address the issues most likely to be resolved using this approach, and suggest that comparisons of natural variation within taxa at several hierarchical levels may substantially increase our understanding of the speciation process.

scholarly journals Characterization of nitrogen deposition by means of atmospheric biomonitors

2017 ◽  
Author(s):  
E. A. Díaz-Álvarez ◽  
E. de la Barrera
Keyword(s):  
Nitrogen Content ◽  
Nitrogen Deposition ◽  
Reactive Nitrogen Species ◽  
C:N Ratio ◽  
Good Alternative ◽  
Biological Species ◽  
Monitoring Networks ◽  
Major Threat ◽  
The Status

AbstractAn increase of nitrogen deposition resulting from human activities is not only a major threat for global biodiversity, but also for human health, especially in highly populated regions. It is thus important and in some instances legally mandated to monitor reactive nitrogen species in the atmosphere. The utilization of widely distributed biological species suitable for biomonitoring may be a good alternative. We assessed the suitability of an ensemble of atmospheric biomonitors of nitrogen deposition by means of an extensive sampling of a lichen, two mosses, and a bromeliad throughout the Valley of Mexico, whose population reaches 30 million, and subsequent measurements of nitrogen metabolism parameters. In all cases we found significant responses of nitrogen content, C:N ratio and the δ15N to season and site. In turn, the δ15N for the mosses responded linearly to the wet deposition. Also, the nitrogen content (R2 = 0.7), the C:N ratio (R2 = 0.6), and δ15N (R2 = 0.5) for the bromeliad had a linear response to NOx. However, the bromeliad was not found in sites with NOx concentrations exceeding 80 ppb, apparently of as a consequence of exceeding nitrogen. These biomonitors can be utilized in tandem to determine the status of atmospheric nitrogenous pollution in regions without monitoring networks for avoiding health problems for ecosystems and humans.

Molecular genetics of familial cutaneous melanoma.

1998 ◽  
Vol 16 (2) ◽  
pp. 670-682 ◽  
Author(s):  
F G Haluska ◽  
F S Hodi
Keyword(s):  
Significant Risk ◽  
Significant Risk Factor ◽  
Melanoma Risk ◽  
Cdkn2a Mutation ◽  
The Status ◽  
History Of ◽  
Sporadic Cases ◽  
Cdk4 Gene ◽  
Technical Factors

PURPOSE A family history of melanoma is a significant risk factor for the disease, and recently several loci that determine susceptibility to the development of melanoma have been identified. The most important of these is p16/CDKN2A. We attempted to determine the degree to which the p16/CDKN2A gene has been implicated in the development of melanoma, and to identify other genetic factors that play a role as well. METHODS We reviewed the literature published since the isolation of p16/CDKN2A and identified 13 studies that report the status of the gene in melanoma samples and 12 reports that examine p16/CDKN2A in melanoma kindreds. We also reviewed associated studies on CDK4 and RB1 involvement in melanoma, and examined the role of p16/CDKN2A in other inherited cancers. RESULTS The evidence strongly implicates p16/CDKN2A in determining predisposition to malignant melanoma. Overall, approximately 20% of families that have been studied show mutations in the gene. However, because of clustering of sporadic cases in families, and potentially because of technical factors, this is likely an underestimate of the proportion of the genetic predisposition for melanoma that is due to p16/CDKN2A mutation. Rare families carry a mutated CDK4 gene that is also responsible for inherited melanoma. CONCLUSION The gene p16/CDKN2A is an important determinant of melanoma risk. A commercial test is presently available to assess the status of this locus. However, because of uncertainties regarding the interpretation of the results of p16/CDKN2A genetic testing, we do not recommend routine clinical use of this test at this time.

scholarly journals Review: Progress and potential of DNA barcoding for species identification of fish species

2017 ◽  
Vol 18 (4) ◽  
pp. 1394-1405
Author(s):  
AYESHA IMTIAZ ◽  
SITI AZIZAH MOHD NOR ◽  
DARLINA MD. NAIM
Keyword(s):  
Dna Barcoding ◽  
Species Identification ◽  
Fish Species ◽  
Mitochondrial Gene ◽  
Biological Species ◽  
Molecular Technique ◽  
Base Pairs ◽  
Main Challenge ◽  
The Status ◽  
Group A

Imtiaz A, Mohd Nor SA, Md. Naim D. 2017. Review: Progress and potential of DNA barcoding for species identification of fish species. Biodiversitas 18: 1394-1405. DNA barcoding is a molecular technique to identify species by utilizing 600-800 base pairs genetic primer segments of mitochondrial gene cytochrome oxidase I. DNA barcoding has high potential to identify species into taxa, resolves ambiguousness in species identification, helps in accurate species identification, categorize species for conservation and also communize the information in the form of database system. The main challenge to this technique is regarding the use of barcoding information on ‘biological species concept’. The extreme diversity of fish and their economic importance has made this group a major target of DNA barcoding. DNA barcoding can assign the status of known to unknown sample but it also has the ability to detect previously un-sampled species as distinct. In this review, we present an overview of DNA barcoding and introduce current advances and limitation of this promising technique.

scholarly journals Diversity of Fungi Isolated From Coffee Farms in Kenya

2021 ◽  
Vol 9 (2) ◽  
pp. 120-129
Author(s):  
Happiness Nyambuge Msenya ◽  
Getrude Okutoyi Alworah ◽  
Stephen Runo ◽  
Douglas Watuku Miano ◽  
Mary Wanjiku Gikungu ◽  
...  
Keyword(s):  
Insect Pests ◽  
Fungal Species ◽  
Biological Species ◽  
Pathology Laboratory ◽  
Tissue Samples ◽  
Pests And Diseases ◽  
The Status ◽  
Identification Of Fungi ◽  
Microscopic Features ◽  
Biocontrol Potential

Diversity of biological species confers benefits to the sustainability of the ecosystem. This study was aimed at determining the diversity of fungi to show the status of soil and coffee plant richness of fungi for sustainable coffee cultivation and future sustainable disease management. Soil and plant tissue samples were collected from coffee farms in Kirinyaga County, while laboratory studies were done at the Plant Pathology Laboratory, Coffee Research Institute, Ruiru, Kenya. The fungal species were isolated from soil and coffee berries. Berries were washed and the fungi allowed to sporulate for 24 hrs. Lesions were excised and serial dilutions made. Fungi were isolated from soil by serial dilution of 10-3. Using the spread plate method, 1 ml of the dilution was plated on potato dextrose agar and incubated at room temperature for ten days. Identification of fungi at the genus level was carried out by using macroscopic and microscopic features. The results showed diverse fungi in both soil and berries which included Aspergillus, Trichoderm, Penicillium, Epicoccum, Cladosporium, Fusarium, Alternaria, Phoma, Rhizopu, Colletotrichum kahawae.The results further showed that Colletotrichum and Cladosporium were the most abundant in the berries at 76% for both species. Fusarium was the most prevalent microorganism in soil at 50% followed by Cladosporium and Penicillium at 20% each. The farms were generally less rich in prevalence of economic important fungi having Trichoderma and Epicoccum at less than 10%. This is a contributing factor to low productivity of coffee due to the lack of growth promoting fungi. This study recommends further studies on the Biocontrol potential of the isolated fungi against coffee insect pests and diseases.

scholarly journals Detection of African swine fever virus in pigs in Southwest Nigeria

2021 ◽  
pp. 1840-1845
Author(s):  
Emmanuel Jolaoluwa Awosanya ◽  
Babasola Oluseyi Olugasa ◽  
Fufa Ido Gimba ◽  
Mohd Yusoff Sabri ◽  
Gabriel Adetunji Ogundipe
Keyword(s):  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Conventional Polymerase Chain Reaction ◽  
Field Strain ◽  
Genotype I ◽  
The Status ◽  
Shared Ancestry ◽  
Southwest Nigeria ◽  
Sporadic Cases ◽  
Southwest Region

Background and Aim: Nigeria experienced repeated outbreaks of African swine fever (ASF) in pig herds between 1997 and 2005 in the southwest region of the country. ASF is believed to currently be enzootic in this region. The status of enzootic transmission of ASF virus strain to pigs is; however, unknown. Twenty-three genotypes of the ASF virus based on the p72 gene are found across Africa. This study aimed to identify the current circulating field strain(s) of the ASF virus in Southwest Nigeria and characterized evolutionary trends. Materials and Methods: DNA samples were extracted from 144 pooled blood samples obtained from 2012 to 2013 following the manufacturer's instructions. DNA was used for conventional polymerase chain reaction using primers targeting the p72 gene and amplified products sequenced with Sanger's sequencing. Sequences were analyzed for homology and phylogenetic relationships. Results: Eleven of 144 samples (7.6%) showed bands at 950 bp. A new field strain of ASF virus of genotype I that shared ancestry with ASF virus strains or isolates from Spain and Brazil was identified among pig herds. The new strain differs phylogenetically in amino acid composition compared with previously identified ASF virus field strains. Conclusion: The currently circulating field strain of ASF virus suggests a mutation responsible for decreased morbidity and mortality recorded in sporadic cases.

The study of interfacial reactions of nickel thin films on GaAs

1983 ◽  
Vol 41 ◽  
pp. 156-157
Author(s):  
L.J. Chen ◽  
Y.F. Hsieh
Keyword(s):  
Thin Films ◽  
Integrated Circuits ◽  
Interfacial Reactions ◽  
Metal Contacts ◽  
Nickel Thin Films ◽  
Thin Foils ◽  
The Status ◽  
Si Doped ◽  
Electron Microscopes

One measure of the maturity of a device technology is the ease and reliability of applying contact metallurgy. Compared to metal contact of silicon, the status of GaAs metallization is still at its primitive stage. With the advent of GaAs MESFET and integrated circuits, very stringent requirements were placed on their metal contacts. During the past few years, extensive researches have been conducted in the area of Au-Ge-Ni in order to lower contact resistances and improve uniformity. In this paper, we report the results of TEM study of interfacial reactions between Ni and GaAs as part of the attempt to understand the role of nickel in Au-Ge-Ni contact of GaAs.N-type, Si-doped, (001) oriented GaAs wafers, 15 mil in thickness, were grown by gradient-freeze method. Nickel thin films, 300Å in thickness, were e-gun deposited on GaAs wafers. The samples were then annealed in dry N2 in a 3-zone diffusion furnace at temperatures 200°C - 600°C for 5-180 minutes. Thin foils for TEM examinations were prepared by chemical polishing from the GaA.s side. TEM investigations were performed with JE0L- 100B and JE0L-200CX electron microscopes.

A TEM study of electron tunneling in biological macromolecules

1987 ◽  
Vol 45 ◽  
pp. 140-141
Author(s):  
J. A. Panitz
Keyword(s):  
Stark Effect ◽  
Electron Tunneling ◽  
Imaging Modality ◽  
Tunneling Current ◽  
Biological Species ◽  
Scanning Tunneling ◽  
Biological Macromolecules ◽  
Flat Surfaces ◽  
Virus Particles ◽  
Stm Images

Tunneling is a ubiquitous phenomenon. Alpha particle disintegration, the Stark effect, superconductivity in thin films, field-emission, and field-ionization are examples of electron tunneling phenomena. In the scanning tunneling microscope (STM) electron tunneling is used as an imaging modality. STM images of flat surfaces show structure at the atomic level. However, STM images of large biological species deposited onto flat surfaces are disappointing. For example, unstained virus particles imaged in the STM do not resemble their TEM counterparts.It is not clear how an STM image of a biological species is formed. Most biological species are large compared to the nominal electrode separation of ∼ 1nm that is required for electron tunneling. To form an image of a biological species, the tunneling electrodes must be separated by a distance that would normally be too large for a tunneling current to be observed.

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