CAML Does Not Modulate Tetherin-Mediated Restriction of HIV-1 Particle Release

Background: Tetherin/BST-2 is a recently-identified potent restriction factor in human cells that restricts HIV particle release following particle formation and budding at the plasma membrane. Vpu counteracts tetherin’s restriction of particle release in a manner that has not yet been fully defined. We recently identified calcium-modulating cyclophilin ligand (CAML) as a Vpu-interacting protein that also restricts particle release. We hypothesized that CAML may act to enhance tetherinmediated restriction of particle release and thereby explain how two distinct factors could be responsible for Vpuresponsive restriction. Methodology/Principal Findings: Endogenous levels of tetherin in human cells correlated well with their restriction pattern and responsiveness to Vpu, while levels of cellular CAML protein did not. Tetherin but not CAML was inducible by interferon in a wide variety of human cells. Stable depletion of human CAML in restrictive HeLa cells had no effect on cell surface levels of tetherin, and failed to relieve tetherin-mediated restriction. Stable depletion of tetherin from HeLa cells, in contrast, rendered HeLa cells permissive and Vpu-unresponsive. Tetherin but not CAML expression in permissive human cells rendered them restrictive and Vpu responsive. Depletion of CAML had no influence on cell surface levels of tetherin. Conclusions/Significance: We conclude that tetherin restricts particle release and does not require CAML for this effect

Oral diet management for carcinoma at the base of tongue with radiotherapy and chemotherapy associated dysphagia: a case report

IntroductionTongue cancer is one of the common malignancy of the head and neck, and directly impacts chewing, swallowing, and other eating activities. Based on the evidence-based guidelines and clinical management, this paper presents nutrition management experience of a patient with tongue cancer who had a dysphagia and feeding reflux while undergoing radiotherapy and chemotherapy.MethodsNutritional risk screening and comprehensive nutritional assessment were performed based on the patient’s medical history, and personalized nutritional programs were developed under the guidance of the clinical pharmaceutical consensus of parenteral nutrition and nutritional treatment guidelines for patients with tumors during radiotherapy. For the management of oral feeding, the patient’s swallowing function was evaluated to manage oral feeding. Thickening powders were used to improve the consistency of the patient’s food, which successfully achieved oral feeding of the patient.ResultsThe patient finally ate five meals a day by mouth, and energy requirements were met using industrialized nutritional supplements, and homogenized food was added in between the meals. The energy provided by enteral nutrition can reached approximately 60–75%. The patient’s weight and albumin levels had increased significantly at the time of discharge.DiscussionThe nutritional management of patients with dysphagia should be jointly managed by clinicians, nurses, nutritionists, and family members to effectively improve the quality of life (QOL) and nutritional status of patients. To ensure adequate nutritional supply, appropriate swallowing training may delay the deterioration of the chewing function and improve the eating experience of such patients

Gp120 stability on HIV-1 virions and Gag-Env pseudovirions is enhanced by an uncleaved Gag core

AbstractHuman immunodeficiency virus type-1 (HIV-1) particles incorporate a trimeric envelope complex (Env) made of gp120 (SU) and gp41 (TM) heterodimers. It has been previously established that soluble CD4 (sCD4) interaction leads to shedding of gp120 from viral particles, and that gp120 may also be easily lost from virions during incubation or particle purification procedures. In the design of HIV particle or pseudovirion-based HIV vaccines, it may be important to develop strategies to maximize the gp120 content of particles. We analyzed the gp120 retention of HIV-1 laboratory-adapted isolates and primary isolates following incubation with sCD4 and variations in temperature. NL4-3 shed gp120 readily in a temperature- and sCD4-dependent manner. Surprisingly, inactivation of the viral protease led to markedly reduced shedding of gp120. Gp120 shedding was shown to vary markedly between HIV-1 strains, and was not strictly determined by whether the isolate was adapted to growth on immortalized T cell lines or was a primary isolate. Pseudovirions produced by expression of codon-optimized gag and env genes also demonstrated enhanced gp120 retention when an immature core structure was maintained. Pseudovirions of optimal stability were produced through a combination of an immature Gag protein core and a primary isolate Env. These results support the feasibility of utilizing pseudovirion particles as immunogens for the induction of humoral responses directed against native envelope structures

Power, supply chain integration and quality performance of agricultural products: evidence from contract farming in China

Improving the quality of agricultural products is crucial for facilitating sustainable agricultural development. One widely embraced approach is contract farming, which generates guarantees—necessary for sustaining the continuous operations of vulnerable farmers—while enabling manufacturers to manage the aggregate supply chain risks and prices. Although management researchers have investigated power and quality performance issues between organisations, few have examined their impact on contract farming. This paper extends the literature by examining the relationships between power, supply chain integration and the quality performance of agricultural products, from the perspectives of farm households and agribusiness companies in contract farming. This study proposes and empirically examines a model, applying survey data from 78 agricultural companies and 321 peasant householders in China. The results show that different types of power have different effects on contract farming. In particular, non-economic power significantly and positively affects supply chain integration. Its impact on process coordination is greater than its impact on information sharing. The effect of economic power on supply chain integration is different from the binary perspective. These findings have positive theoretical and practical significance for agribusiness and will help farmers to improve the quality of primary agricultural products and achieve sustainable agricultural development

The Intracellular Virus-Containing Compartments in Primary Human Macrophages Are Largely Inaccessible to Antibodies and Small Molecules

HIV-1 assembly and release occurs at the plasma membrane of human T lymphocytes and model epithelial cell lines, whereas in macrophages intracellular sites of virus assembly or accumulation predominate. The origin of the intracellular virus-containing compartment (VCC) has been controversial. This compartment is enriched in markers of the multivesicular body, and has been described as a modified endosomal compartment. Several studies of this compartment have revealed the presence of small channels connecting to the plasma membrane, suggesting that instead of an endosomal origin the compartment is a modified plasma membrane compartment. If the compartment is accessible to the external environment, this would have important implications for antiviral immune responses and antiviral therapy. We performed a series of experiments designed to determine if the VCC in macrophages was open to the external environment and accessible to antibodies and small molecules. The majority of VCCs were found to be inaccessible to exogenously-applied antibodies to tetraspanins in the absence of membrane permeabilization, while tetraspanin staining was readily observed following membrane permeabilization. Cationized ferritin was utilized to stain the plasma membrane, and revealed that the majority of virus-containing compartments were inaccessible to ferritin. Low molecular weight dextrans could access only a very small percentage of VCCs, and these tended to be more peripheral compartments. We conclude that the VCCs in monocyte-derived human macrophages are heterogeneous, but the majority of VCCs are closed to the external environment

Rab11-FIP1C and Rab14 Direct Plasma Membrane Sorting and Particle Incorporation of the HIV-1 Envelope Glycoprotein Complex

The incorporation of the envelope glycoprotein complex (Env) onto the developing particle is a crucial step in the HIV-1 lifecycle. The long cytoplasmic tail (CT) of Env is required for the incorporation of Env onto HIV particles in T cells and macrophages. Here we identify the Rab11a-FIP1C/RCP protein as an essential cofactor for HIV-1 Env incorporation onto particles in relevant human cells. Depletion of FIP1C reduced Env incorporation in a cytoplasmic tail-dependent manner, and was rescued by replenishment of FIP1C. FIP1C was redistributed out of the endosomal recycling complex to the plasma membrane by wild type Env protein but not by CT-truncated Env. Rab14 was required for HIV-1 Env incorporation, and FIP1C mutants incapable of binding Rab14 failed to rescue Env incorporation. Expression of FIP1C and Rab14 led to an enhancement of Env incorporation, indicating that these trafficking factors are normally limiting for CT-dependent Env incorporation onto particles. These findings support a model for HIV-1 Env incorporation in which specific targeting to the particle assembly microdomain on the plasma membrane is mediated by FIP1C and Rab14. © 2013 Qi et al.Link_to_subscribed_fulltex

Independent Segregation of Human Immunodeficiency Virus Type 1 Gag Protein Complexes and Lipid Rafts

Formation of human immunodeficiency virus type 1 (HIV-1) particles takes place at the plasma membrane of cells and is directed by the Pr55(Gag) polyprotein. A functional assembly domain (the M domain) within the N-terminal portion of Pr55(Gag) mediates the interaction of Gag with cellular membranes. However, the determinants that provide specificity for assembly on the plasma membrane, as opposed to intracellular membranes, have not been identified. Recently, it was reported that Pr55(Gag) interacts with lipid raft microdomains of the plasma membrane. We sought to identify the domains within Pr55(Gag) that contribute to lipid raft association of Gag. Here we demonstrate that the I domain is required for interaction with detergent-resistant membrane fractions (DRMs). Mutation of key I-domain residues or loss of myristylation abrogated the association of Gag with DRMs. Thus, the I domain and the M domain combine to mediate Gag-lipid raft interactions as defined by these biochemical criteria. However, Gag protein complexes defined by flotation studies were much denser than classical lipid rafts, failed to incorporate classical lipid raft marker proteins, and were not disrupted by cholesterol extraction. Large sheets of Gag protein were identified in DRM fractions upon examination by electron microscopy. These results indicate that HIV-1 Pr55(Gag) forms detergent-resistant complexes at the cellular periphery that are distinct from lipid raft microdomains