Explanation:
Human immunodeficiency virus type 1 (HIV-1) enters target cells by first binding to the primary receptor CD4 and then to a coreceptor, generally one of the chemokine receptors CCR5 and CXCR4 (4). CD4 binding induces structural changes in the envelope (Env) glycoprotein that form and expose the coreceptor binding site. There are two main interactions between Env and coreceptor (13, 14, 25, 50, 51): the base of the third variable loop (V3) engages the N terminus of the coreceptor, while the crown of the V3 loop that includes the highly conserved GPGR/Q arch motif binds to the extracellular loops of the coreceptor, with the second extracellular loop of the coreceptor being particularly important (16, 25, 35, 48, 62). Although some HIV-1 strains are able to use a variety of different G protein-coupled receptors to gain entry into CD4+ cell lines, the great majority of these viruses use CCR5 and/or CXCR4 as coreceptors to infect primary cells (3, 4, 10, 23, 47, 66). CCR3, GPR15, APJ, and FPRL-1 are among the most frequently used alternative coreceptors when overexpressed on cell lines (11, 26, 43, 47, 57). Rare cases of HIV-1 strains that are able to use FPRL-1 and GPR1, but not CCR5 or CXCR4, have been reported (57); however, their in vivo relevance remains unknown.
To characterize the biological processes underlying HIV/simian immunodeficiency virus (SIV) transmission, we recently developed an experimental strategy that permits the identification, enumeration, and molecular cloning of transmitted/founder (T/F) viruses (28, 53). This strategy, which employs single-genome amplification (SGA) and direct amplicon sequencing of HIV/SIV RNA or DNA from the plasma or infected cells, makes it possible to infer the nucleotide sequence of the viral strain(s) that initiated productive infection weeks earlier (1, 28, 29, 37, 53, 58, 67). An important prediction of this approach has been that inferred T/F viruses are fully functional and encode all proteins necessary to establish a new infection. Indeed, this prediction has been borne out in numerous studies, which have shown that T/F viral genes as well as full-length genomes are biologically active. Sets of T/F Envs have been shown to mediate efficient virus entry in single-round infection assays, and they invariably use CCR5 as a coreceptor (28, 34). Similarly, T/F infectious molecular clones (IMCs) of HIV-1, SIVmac and SIVagm all produce replication competent virus that grow to high titers in primary CD4+ T cells (22, 38, 54).
MATERIALS AND METHODS
Amplification of the HIV-1 env gene. Serial plasma samples collected from an acutely infected plasma donor, ZP6248, were purchased from ZeptoMetrix. A total of seven plasma samples were collected between 12 February and 9 March 1997, and viral loads (VLs) were determined by the COBAS Amplicor HIV-1 monitor test.
Sequence analysis. All SGA amplicons were sequenced directly by cycle sequencing and dye terminator methods using an ABI 3730xl genetic analyzer (Applied Biosystems, Foster City, CA). Individual sequences were assembled and edited using the Sequencher program 4.7 (Gene Codes, Ann Arbor, MI). The env sequences were aligned using CLUSTAL W (60), and manual adjustment for optimal alignment was done using MASE (20).
What is your opinion on the use of stem cells, obtained from fertilized eggs or early stage embryos
USE OF STEM CELL:
The first attempts to turn mature cells back into pluripotent stem cells involved a process called cloning. In the cloning process, an egg is fertilized in the lab, and right after fertilization, the DNA is removed from the egg.These stem cells come from embryos that are three to five days old. These are pluripotent (ploo-RIP-uh-tunt) stem cells, meaning they can divide into more stem cells or can become any type of cell in the body. This versatility allows embryonic stem cells to be used to regenerate or repair diseased tissue and organs.Despite the potential benefit of using human ES cells in the treatment of disease, their use remains controversial because of their derivation from early embryos.Learn more:
brainly.com/question/12483864
3. Which of the following is a major functional characteristic of all organisms? (a) movement,
(b) growth, (c) metabolism, (d) responsiveness, (e) all of these.
Answer:
The correct option is E..all of these
Explanation:
This is because all living exhibit functional characteristics which are movement, respiration, nutrition, irritability, growth, excretion, respiration and death. This characteristics are indication that organisms are living things.
Growth: it is the increase in size of organisms. All living organisms grow, they increase in size , from zygote to adulthood.
Metabolism...all living organisms excreate, they absorb nutrients and remove unwanted waste products and undigested good like sweat, urine e.t.c.
Responsiveness....All living organisms respond to stimulus, they respond to external environment or change.
Complete the sentences by matching the names of trees to the appropriate blanks. to do this, drag the names on the left into the appropriate blanks in the sentences on the right. match the words in the left column to the appropriate blanks in the sentences on the right. terms may be used more than once. make certain you have filled every blank with a term before clicking submit.
1. deciduous trees lose their leaves seasonally and include trees such as maple and elm.
2. conifer leaves are generally thin and needle-like, while seeds are contained in cones. conifers include cedar and pine.
3. evergreens are plants that maintain their leaves in all seasons and include trees such as cedar, elm, and pine.
4. hardwoods reproduce using flowers and have broad leaves; hardwoods include trees such as maple, , and cedar. elm returned you filled in 2 of 10 blanks incorrectly. mango trees are tropical broad leaf plants that maintain their leaves all year long. no credit lost. try again.
Complete question:
Complete the sentences by matching the names of trees to the appropriate blanks. to do this, drag the names on the left into the appropriate blanks in the sentences on the right. match the words in the left column to the appropriate blanks in the sentences on the right. terms may be used more than once. make certain you have filled every blank with a term before clicking submit.
ElmMaple MangoPine Cedar1. deciduous trees lose their leaves seasonally and include trees such as ----- and ----.
2. conifer leaves are generally thin and needle-like, while seeds are contained in cones. conifers include ---- and -----.
3. evergreens are plants that maintain their leaves in all seasons and include trees such as ---, ---, and ---.
4. hardwoods reproduce using flowers and have broad leaves; hardwoods include trees such as ---, ---, and ---.
Answer:
1. deciduous trees lose their leaves seasonally and include trees such as elm and maple.
2. conifer leaves are generally thin and needle-like, while seeds are contained in cones. conifers include pine and cedar.
3. evergreens are plants that maintain their leaves in all seasons and include trees such as Pine, Cedar, and Mango.
Explanation:
Deciduous trees: These plant species lose their leaves every year during the cold and dry autumns and winters, as it is the most limiting period over the year. Foliage resprout again during the warmer wet season when it rains more often, during spring and summer. Template forest biome characterizes for having deciduous trees such as oaks, maple, or elm, among other phanerophyte species.1. deciduous trees lose their leaves seasonally and include trees such as elm and maple.
Conifer: Correspond to the gymnosperm group. They are perennial, vascular, evergreen, woody plants. They characterize for having a straight trunk with secondary growth and no vessels in the xylem tissue. Their branches usually develop horizontally, with needle-like leaves growing on them, unisexual flowers, and seeds included in a cone.
2. conifer leaves are generally thin and needle-like, while seeds are contained in cones. conifers include pine and cedar.
Evergreens: Perennial plants that keep their green leaves the whole year. These are the opposite of the deciduous trees. Tropical forests characterized for having these broadleaf plant species, such as mango, that are favored by the environmental conditions as precipitations are abundant and the average temperature is elevated most of the year. Also, many evergreen plants are typical of the boreal forest. Pines, cypress, cedar, and sequoia are examples of these last ones.
3. evergreens are plants that maintain their leaves in all seasons and include trees such as Pine, Cedar, and Mango.
Hardwoods: Angiosperms. Xylem with vessels. These species present a high diversity in shape, textures, and sizes. They might reproduce asexually or sexually by producing flowers, fruits, and seeds. Also, they might be either evergreen or deciduous.4. hardwoods reproduce using flowers and have broad leaves; hardwoods include trees such as Elm, Maple, and Mango.
If anyone knows this please let me know and explain??
Answer:
I am pretty sure the answer is Melting
Explanation:
True or False: Food Webs are generally more accurate and detailed models of an ecosystem than Food Chains.
Answer:
True
Explanation:
They have more options and possible ways
Answer:
true,
The food web provides a better model of an ecosystem because the food web is a model between MANY different consumers and producers in an ecosystem. While the food chain is a model for just one consumer and producer. ... Because energy is lost as it moves from producers to consumers, the bottom level is the largest.
Name one photosynthesis organism and how it affects the plant.
Answer:
Hey!
Explanation:
Plants like Sunflowers are organisms that use photosynthesis, and photosynthesis makes it so where the plant can get energy out of Radiant Energy. Hope this helps!
