Th ere is something about being human that instills in us a sense of wonder.
When we stop to think about it, the very idea of life seems such a mystery.
Where did we come from? How did life begin? When we look at the
sky, we wonder about the vastness of the universe and whether other life
may exist there. If we look through a microscope at a drop of pond water,
we are amazed at the variety of tiny creatures we see.
Since cells form the very basis of life, it is only natural that our sense
of wonder extends to the cell. Where did...
Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Wertheim cung cấp cho các bạn kiến thức về ngành y đề tài: Complex cell behaviors in development: recent progress and emerging challenges...
This volume is the first book-length survey of caveolae and lipid rafts. Interest has
developed rapidly in the role of these surface microdomains in such diverse fields
as transmembrane signaling, cell locomotion, vascular relaxation, senescence, and
the uptake and exit from cells of viruses and bacteria. Individual chapters in this
volume cover areas as diverse as the forces that induce and maintain membrane
invaginations, and the clinical relevance of multiprotein complexes at the cell surface,
defects in which are associated with cancer, and Alzheimer’s and prion-dependent
Developmental Biology of Hematopoietic Stem Cells
During development, blood cells are produced at different sites. Initially, the yolk sac provides oxygen-carrying red blood cells, and then several sites of intraembryonic blood cell production become involved. These intraembryonic sites engage in sequential order, moving from the genital ridge at a site where the aorta, gonadal tissue, and mesonephros are emerging to the fetal liver and then, in the second trimester, to the bone marrow and spleen.
Tumor angiogenesis is a complex process involving many different cell types that must proliferate, migrate, invade, and differentiate in response to signals from the tumor microenvironment. Endothelial cells (ECs) sprout from host vessels in response to VEGF, bFGF, Ang2, and other proangiogenic stimuli. Sprouting is stimulated by VEGF/VEGFR2, Ang2/Tie-2, and integrin/extracellular matrix (ECM) interactions.
As we were at pains to point out in the companion volume to this monograph,
entitled Complexity in Chemistry: Introduction and Fundamentals,
complexity is to be encountered just about everywhere. All that is needed
for us to see it is a suitably trained eye and it then appears almost magically
in all manner of guises. Because of its ubiquity, complexity has been and
currently still is being defined in a number of different ways. Some of these
definitions have led us to major and powerful new insights.
(BQ) Ebook Biochemistry, cell and molecular biology test consists of approximately 180 multiple-choice questions, a number of which are grouped in sets toward the end of the test and based on descriptions of laboratory situations, diagrams, or experimental results.
Acetylation of the amino terminus of the core histones H3 and H4 induces an open chromatin conformation that promotes transcription initiation. Histone acetylases are components of coactivator complexes recruited to
promoter/enhancer regions by sequence-specific transcription factors during the activation of genes (Fig. 80-4). Histone deacetylases (HDACs; at least 17 are encoded in the human genome) are recruited to genes by transcriptional repressors and prevent the initiation of gene transcription.
Estrogen acts as a proconvulsant in several animal models of epilepsy, including amygdalal
kindling and pentylenetetrazol administration in ovariectomized rats (Hom and
Buterbaugh, 1986). Estrogen induces the formation of new excitatory synapses in the CA1
region of the hippocampus; and further, this estrogenic induction involves activation of Nmethyl-
Daspartate (NMDA) receptors (McEwen, 2002). Increasing the complexity of
hippocampal synaptic density is likely a mechanism for the proconvulsant activity of
In this review, we first describe the mechanisms by which the epidermal
growth factor receptor generates a Ca
signal and, subsequently, we com-pile the available experimental evidence regarding the role that the
⁄calmodulin complex, formed after the rise in cytosolic free Ca
concentration, exerts on the receptor.
An increasing amount of expressed sequence tag (EST) and genomic data,
predominantly for the cnidarians Acropora, Hydraand Nematostella,
reveals that cnidarians have a high genomic complexity, despite being one
of the morphologically simplest multicellular animals.
High-molecular-mass PC complexes (PC-HMWCs) constituted by phyto-chelatins (PCs), cadmium and sulfide are synthesized by several organisms
after exposure to cadmium. In this study, PC-HMWCs were isolated from
photoheterotrophicEuglena gracilisand purified to homogeneity, resulting
in compounds of molecular mass 50–380 kDa depending on the CdCl2and
sulfate concentrations in the culture medium.
Cell-free protein synthesis using cell extracts from
Escherichia coli, wheat germ and rabbit reticulocytes
has been used for over 40 years to produce small
amounts of radiolabeled proteins for identification of
gene products and other applications. In the E. coli
system programmed with plasmid DNA, the cell
extract contains or is supplemented with an RNA po-lymerase to transcribe the gene, and the mRNAs are
translated by a complex mixture that contains ribo-somes and a full complement of initiation,...
The virus protein linked to the genome (VPg) of plant potyviruses is a
25-kDa protein covalently attached to the genomic RNA 5¢ end. It was
previously reported that VPg binds specifically to eIF4E, the mRNAcap-binding protein of the eukaryotic translation initiation complex. We per-formed a spectroscopic study of the interactions between lettuce eIF4E and
VPg from lettuce mosaic virus (LMV).
The 6-kDa early secretory antigenic target (ESAT-6) and culture filtrate
protein-10 (CFP-10), expressed from the region of deletion-1 (RD1) of
Mycobacterium tuberculosisH37Rv, are known to play a key role in viru-lence. In this study, we explored the thermodynamic and biochemical chan-ges associated with the formation of the 1 : 1 heterodimeric complex
between ESAT-6 and CFP-10.
The crystal structure ofPterocarpus angolensislectin is determined in its
ligand-free state, in complex with the fucosylated biantennary complex type
decasaccharide NA2F, and in complex with a series of smaller oligosaccha-ride constituents of NA2F. These results together with thermodynamic
binding data indicate that the complete oligosaccharide binding site of the
lectin consists of five subsites allowing the specific recognition of the penta-saccharide GlcNAcb(1–2)Mana(1–3)[GlcNAcb(1–2)Mana(1–6)]Man. ...
In the yeast Saccharomyces cerevisiae, plasma membrane H
activated by d-glucose. We found that in the absence of glucose, this
enzyme forms a complex with acetylated tubulin. Acetylated tubulin usu-ally displays hydrophilic properties, but behaves as a hydrophobic com-pound when complexed with H
-ATPase, and therefore partitions into
a detergent phase.
As an adaptation process to the growth retardation provoked by the presence of nonlethal concentrations of ergosterol biosynthesis inhibitors, Ustilago maydis alters the ratio of linoleic to oleic acid bound to plasma membrane ´ complex lipids [Hernandez, A., Cooke, D.T., Lewis, M. & Clarkson, D.T. (1997) Microbiology 143, 3165–3174]. This alteration increases plasma membrane H+-ATPase hydrolytic activity.
The selection of functional T cells is mediated by interactions between the
T cell antigen receptor and self-peptide major histocompatibility complex
expressed on thymic epithelium. These interactions either lead to survival
and development or death.
Tetratricopeptide repeats (TPRs) are protein domains that mediate key
protein–protein interactions in cells. Several TPR domains bind the C-ter-mini of the chaperones heat shock protein (Hsp)90 and⁄or Hsp70, and
exchange of such binding partners is key for the heat shock response.