93 results match your criteria: "Cornell University Weill Medical College[Affiliation]"

Methyl-accepting chemotaxis proteins (MCPs), also termed transducer-like proteins (Tlps), serve as sensors in bacterial chemotactic signalling, and detect attractants and promote bacterial movement towards suitable sites for colonization. Campylobacter jejuni is a leading cause of human enteritis, but the mechanisms responsible for bacterial chemotaxis and early colonization in the jejunum of hosts are poorly understood. In the present study, we identified several types of bile and sodium deoxycholate (SDC) acting as chemotactic attractants of C.

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The structure of the postnatal mammalian cerebral cortex is an assembly of numerous mature neurons that exhibit proper neurite outgrowth and axonal and dendritic morphology. While many protein coding genes are shown to be involved in neuronal maturation, the role of microRNAs (miRNAs) in this process is also becoming evident. We here report that blocking miRNA biogenesis in differentiated neurons results in microcephaly like phenotypes in the postnatal mouse brain.

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Tuning the cell fate of neurons and glia by microRNAs.

Curr Opin Neurobiol

December 2013

Department of Cell and Developmental Biology, Cornell University Weill Medical College, 1300 York Avenue, Box 60, New York, NY 10065, United States.

The proper function of the nervous system depends on precise production and connection of distinct neurons and glia. Cell fate determination of neurons and glia is tightly controlled by complex gene expression regulation in the developing and adult nervous system. Emerging evidence has demonstrated the importance of noncoding microRNAs (miRNAs) in neural development and function.

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G protein-coupled receptors (GPCRs) mediate transmembrane signaling. Before ligand binding, GPCRs exist in a basal state. Crystal structures of several GPCRs bound with antagonists or agonists have been solved.

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Filopodia are cell surface protrusions that are essential for cell migration. This finger-like structure is supported by rigid tightly bundled actin filaments. The protein responsible for actin bundling in filopodia is fascin.

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Mouse models for tumor metastasis.

Methods Mol Biol

February 2013

Department of Physiology, Cornell University Weill Medical College, New York, USA.

Tumor metastasis is the main cause of death of cancer patients. Here we describe two mouse models for investigating tumor metastasis. In the first spontaneous metastasis mouse model, 4T1 mouse breast tumor cells are injected into the mammary gland of host mice and the metastasis of 4T1 tumor cells into the lung are examined with a colonogenic assay.

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Understanding how the material properties of bone tissue from the various forms of osteogenesis imperfecta (OI) differ will allow us to tailor treatment regimens for affected patients. To this end, we characterized the bone structure and material properties of two mouse models of OI, the osteogenesis imperfecta mouse (oim/oim) and fragilitas ossium (fro/fro), in which bone fragility is due to a genetic defect in collagen type I and a defect in osteoblast matrix mineralization, respectively. Bones from 3 to 6 month old animals were examined using Fourier transform infrared spectroscopic imaging (FTIRI), microcomputed tomography (micro-CT), histology, and biochemical analysis.

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The cytokines oncostatin M (OSM) and IL-6 promote breast cancer cell migration and metastasis. Both cytokines activate STAT3, a member of the STAT (signal transducers and activators of transcription) family of transcription factors. Through transcriptional regulation of its target genes, STAT3 controls a wide range of cellular processes, including cellular proliferation, oncogenesis, and cancer metastasis.

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Heterotrimeric G proteins are critical transducers of cellular signaling. In addition to their classic roles in relaying signals from G protein-coupled receptors (GPCRs), heterotrimeric G proteins also mediate physiological functions from non-GPCRs. Previously, we have shown that Gα(13), a member of the heterotrimeric G proteins, is essential for growth factor receptor-induced actin cytoskeletal reorganization such as dynamic dorsal ruffle turnover and cell migration.

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Objective: To review notable aneurysm cases that required complex decision making from a single institution and to examine available literature when relevant to highlight evidence-based paradigms for treatment of complex aneurysms.

Methods: Case illustrations were used to highlight topics in complex aneurysm treatments. Reviews of the literature were conducted to evaluate the evidence for available treatment models.

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Tumour metastasis is the primary cause of death of cancer patients. Development of new therapeutics preventing tumour metastasis is urgently needed. Migrastatin is a natural product secreted by Streptomyces, and synthesized migrastatin analogues such as macroketone are potent inhibitors of metastatic tumour cell migration, invasion and metastasis.

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A new Rac/PAK/GC/cGMP signaling pathway.

Mol Cell Biochem

January 2010

Department of Physiology, Cornell University Weill Medical College, New York, NY 10065, USA.

Guanosine 3',5'-cyclic monophosphate (cGMP) and small GTPase Rac are critical regulators of cell functions. Recently, Rac has been shown to use its downstream effector p21-activated kinase (PAK) to directly activate transmembrane guanylyl cyclases (GCs). This novel Rac/PAK/GC/cGMP signaling pathway bridges Rac and cGMP, and provides a general molecular mechanism for diverse receptors to regulate physiological functions such as cell migration through elevating the cellular cGMP level.

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We compared lymphocyte subsets and cytokine responses to bacteria among term, preterm infants, and adults. Lymphocyte subset percentages in cord blood (22 preterm, 27 term neonates) and peripheral blood from 21 adults and cytokine/chemokine interleukin (IL)-6, IL-8, IL-10, IL-12, interferon gamma (IFN gamma) responses to Escherichia coli, group B Streptococcus (GBS), Staphylococcus epidermidis, and Lactobacillus plantarum (Lp299v) were assessed by flow cytometry. Preterm compared with term infants had increased CD8 (+) T cells (p = 0.

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Inactivation of the structural gene for the RecQ family member, BLM in human, Sgs1 in budding yeast, or Rqh1 in fission yeast leads to inappropriate recombination, chromosome abnormalities, and disturbed replication fork progression. Studies with yeasts have demonstrated that auxiliary gene functions can contribute in overlapping ways with Sgs1 or Rqh1 to circumvent or overcome lesions in DNA caused by certain genotoxic agents. In the combined absence of these functions, recombination-mediated processes lead to severe loss of fitness.

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Guanylyl cyclases (GCs) catalyze the conversion of GTP to the second messenger cGMP. While some transmembrane GCs are receptors for extracellular ligands, other transmembrane GCs such as retinal-specific GC-E and GC-F are stimulated by cellular proteins. GC-D is expressed in a special group of olfactory sensory neurons.

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The C-terminal region of Brh2 (Brh2(CT)), the BRCA2 homolog in Ustilago maydis, is highly conserved and aligns with the DSS1/DNA-binding domain (DBD) of mammalian BRCA2, while the N-terminal region (Brh2(NT)) is poorly conserved and has no obvious functional domain except for the single Rad51-interacting BRC element. Paradoxically, Brh2(NT), but not Brh2(CT), complements the DNA repair and recombination deficiency of the brh2 mutant. We show here that Brh2(NT) exhibits an unexpected DNA binding activity with properties similar to that of the full-length protein.

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Beta glucans are cell wall constituents of yeast, fungi and bacteria, as well as mushrooms and barley. Glucans are not expressed on mammalian cells and are recognized as pathogen-associated molecular patterns (PAMPS) by pattern recognition receptors (PRR). Beta glucans have potential activity as biological response modifiers for hematopoiesis and enhancement of bone marrow recovery after injury.

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The homologous recombination system of Ustilago maydis.

Fungal Genet Biol

August 2008

Cornell University Weill Medical College, Department of Microbiology and Immunology, NY 10021, USA.

Homologous recombination is a high fidelity, template-dependent process that is used in repair of damaged DNA, recovery of broken replication forks, and disjunction of homologous chromosomes in meiosis. Much of what is known about recombination genes and mechanisms comes from studies on baker's yeast. Ustilago maydis, a basidiomycete fungus, is distant evolutionarily from baker's yeast and so offers the possibility of gaining insight into recombination from an alternative perspective.

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Cell migration is critical for animal development and physiological as well as pathological responses. One important step during cell migration is the formation of lamellipodia at the leading edge of migrating cells. Here we report that the second messenger cAMP inhibits the migration of mouse embryonic fibroblast cells and mouse breast tumor cells.

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A single Rad52-related protein is evident by blast analysis of the Ustilago maydis genome database. Mutants created by disruption of the structural gene exhibited few discernible defects in resistance to UV, ionizing radiation, chemical alkylating or cross-linking agents. No deficiency was noted in spontaneous mutator activity, allelic recombination or meiosis.

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D-loop formation by Brh2 protein of Ustilago maydis.

Proc Natl Acad Sci U S A

January 2008

Department of Microbiology and Immunology, Cornell University Weill Medical College, New York, NY 10065, USA.

Brh2, the ortholog of the BRCA2 tumor suppressor in Ustilago maydis, works hand in hand with Rad51 to promote repair of DNA by homologous recombination. Previous studies established that Brh2 can stimulate DNA strand exchange by enabling Rad51 nucleoprotein filament formation on replication protein A-coated ssDNA. But, more recently, it was noted that Brh2 has an inherent DNA annealing activity, raising the notion that it might have roles in recombination in addition to or beyond the mediator function.

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Classically, G protein-coupled receptors (GPCRs) relay signals by directly activating heterotrimeric guanine nucleotide-binding proteins (G proteins). Increasing evidence indicates that GPCRs may also signal through G protein-independent pathways. JAK/STATs, Src-family tyrosine kinases, GRKs/beta-arrestins, and PDZ domain-containing proteins have been suggested to directly relay signals from GPCRs independent of G proteins.

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Ustilago maydis is a phytopathogenic fungus exhibiting extreme resistance to UV and ionizing radiation. The molecular mechanisms underlying this resistance are as yet unknown. The recently determined genome sequence was examined for clues to the radiation resistance, focusing on proteins in homologous recombination, but there was little that was unusual about them.

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A wide range of extracellular signals are transduced by G protein-coupled receptors (GPCRs). When activated by ligands, GPCRs can activate associated heterotrimeric guanine nucleotide-binding proteins (G proteins), which in turn act on various effectors. Increasing evidence indicates that GPCRs also signal independently of heterotrimeric G proteins.

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