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

Elicitation of Neutralizing Antibodies Directed against CD4-Induced Epitope(s) Using a CD4 Mimetic Cross-Linked to a HIV-1 Envelope Glycoprotein

The identification of HIV-1 envelope glycoprotein (Env) structures that can generate broadly neutralizing antibodies (BNAbs) is pivotal to the development of a successful vaccine against HIV-1 aimed at eliciting effective humoral immune responses. To that end, the production of novel Env structure(s) that might induce BNAbs by presentation of conserved epitopes, which are otherwise occluded, is critical. Here, we focus on a structure that stabilizes Env in a conformation representative of its primary (CD4) receptor-bound state, thereby exposing highly conserved “CD4 induced” (CD4i) epitope(s) known to be important for co-receptor binding and subsequent virus infection. A CD4-mimetic miniprotein, miniCD4 (M64U1-SH), was produced and covalently complexed to recombinant, trimeric gp140 envelope glycoprotein (gp140) using site-specific disulfide linkages. The resulting gp140-miniCD4 (gp140-S-S-M64U1) complex was recognized by CD4i antibodies and the HIV-1 co-receptor, CCR5. The gp140-miniCD4 complex elicited the highest titers of CD4i binding antibodies as well as enhanced neutralizing antibodies against Tier 1 viruses as compared to gp140 protein alone following immunization of rabbits. Neutralization against HIV-27312/V434M and additional serum mapping confirm the specific elicitation of antibodies directed to the CD4i epitope(s). These results demonstrate the utility of structure-based approach in improving immunogenic response against specific region, such as the CD4i epitope(s) here, and its potential role in vaccine application

Endophytes vs tree pathogens and pests: can they be used as biological control agents to improve tree health?

Like all other plants, trees are vulnerable to attack by a multitude of pests and pathogens. Current control measures for many of these diseases are limited and relatively ineffective. Several methods, including the use of conventional synthetic agro-chemicals, are employed to reduce the impact of pests and diseases. However, because of mounting concerns about adverse effects on the environment and a variety of economic reasons, this limited management of tree diseases by chemical methods is losing ground. The use of biological control, as a more environmentally friendly alternative, is becoming increasingly popular in plant protection. This can include the deployment of soil inoculants and foliar sprays, but the increased knowledge of microbial ecology in the phytosphere, in particular phylloplane microbes and endophytes, has stimulated new thinking for biocontrol approaches. Endophytes are microbes that live within plant tissues. As such, they hold potential as biocontrol agents against plant diseases because they are able to colonize the same ecological niche favoured by many invading pathogens. However, the development and exploitation of endophytes as biocontrol agents will have to overcome numerous challenges. The optimization and improvement of strategies employed in endophyte research can contribute towards discovering effective and competent biocontrol agents. The impact of environment and plant genotype on selecting potentially beneficial and exploitable endophytes for biocontrol is poorly understood. How endophytes synergise or antagonise one another is also an important factor. This review focusses on recent research addressing the biocontrol of plant diseases and pests using endophytic fungi and bacteria, alongside the challenges and limitations encountered and how these can be overcome. We frame this review in the context of tree pests and diseases, since trees are arguably the most difficult plant species to study, work on and manage, yet they represent one of the most important organisms on Earth

Endophytes vs tree pathogens and pests: can they be used as biological control agents to improve tree health?

Like all other plants, trees are vulnerable to attack by a multitude of pests and pathogens. Current control measures for many of these diseases are limited and relatively ineffective. Several methods, including the use of conventional synthetic agro-chemicals, are employed to reduce the impact of pests and diseases. However, because of mounting concerns about adverse effects on the environment and a variety of economic reasons, this limited management of tree diseases by chemical methods is losing ground. The use of biological control, as a more environmentally friendly alternative, is becoming increasingly popular in plant protection. This can include the deployment of soil inoculants and foliar sprays, but the increased knowledge of microbial ecology in the phytosphere, in particular phylloplane microbes and endophytes, has stimulated new thinking for biocontrol approaches. Endophytes are microbes that live within plant tissues. As such, they hold potential as biocontrol agents against plant diseases because they are able to colonize the same ecological niche favoured by many invading pathogens. However, the development and exploitation of endophytes as biocontrol agents will have to overcome numerous challenges. The optimization and improvement of strategies employed in endophyte research can contribute towards discovering effective and competent biocontrol agents. The impact of environment and plant genotype on selecting potentially beneficial and exploitable endophytes for biocontrol is poorly understood. How endophytes synergise or antagonise one another is also an important factor. This review focusses on recent research addressing the biocontrol of plant diseases and pests using endophytic fungi and bacteria, alongside the challenges and limitations encountered and how these can be overcome. We frame this review in the context of tree pests and diseases, since trees are arguably the most difficult plant species to study, work on and manage, yet they represent one of the most important organisms on Earth

Informed stakeholder support for managing invasive <i>Hydrilla verticillata</i> linked to wildlife deaths in a Southeastern reservoir

<p>Fouts KL, Poudyal, NC, Moore R, Herrin J, Wilde, SB. 2017. Informed stakeholder support for managing invasive <i>Hydrilla verticillata</i> linked to wildlife deaths in a Southeastern reservoir. Lake Reserve Manage. 00:1–10.</p> <p>Public opinion surveys prior to implementing management actions provide managing agencies with a detailed understanding of stakeholders' attitudes and help inform the general public on the complexity of potential management actions. Like many other Southeastern U.S. reservoirs, J. Strom Thurmond (JST), on the border of Georgia and South Carolina, has been infested with nonnative hydrilla (<i>Hydrilla verticillata</i>). Avian Vacuolar Myelinopathy (AVM), a fatal wildlife disease linked to a neurotoxic cyanobacterial species growing on hydrilla, has been documented on this 28,733-ha reservoir since 1998, when the hydrilla acreage first exceeded 350 ha. As of 2016, 90 bald eagle (<i>Haliaeetus leucocephalus</i>) mortalities and hundreds of waterfowl deaths have been attributed to AVM disease on JST. To assess and compare the diverse stakeholders' attitudes toward aquatic vegetation, knowledge of AVM, and support for management actions to remove hydrilla, a mail survey was conducted targeting various JST user groups (anglers, boaters, campers, waterfowl hunters, and shoreline property owners). Generally, respondents were overwhelmingly in favor of reducing hydrilla density on JST, but shoreline permit holders (homeowners) were significantly more supportive of hydrilla management than boaters. Similarly, all user groups supported management actions to remove aquatic vegetation, including stocking triploid sterile grass carp (<i>Ctenopharyngodon idella</i>). Support for removing hydrilla was found to be significantly higher among users knowledgeable of AVM, suggesting that outreach activities educating the public on the effects and prevention of the disease would help enhance stakeholder support for hydrilla removal and management in public reservoirs.</p

Records Review of Musculoskeletal Injuries in Aeromedical Evacuation Personnel

Background: Aeromedical evacuation providers care for patients during air transport. By applying standard medical practices, oftentimes developed for ground care, these practitioners perform their mission duties under additional physical stress in this unique medical environment. Awkward postures and excessive forces are common occurrences among personnel operating in this domain. Additionally, anecdotal reports highlight the risk of developing musculoskeletal injuries for these providers. Currently, there is limited research focusing on musculoskeletal injuries in aeromedical evacuation providers. Purpose: To determine the prevalence of musculoskeletal injuries and associated symptoms in aeromedical evacuation providers to understand the risk and burden of these injuries to military personnel. Methods: This study utilized a retrospective review of military medical records containing ICD-9 codes to investigate the incidence of musculoskeletal injuries within flight nurses and medical technicians compared to their non-flying counterparts from 2006 through 2011. Data were analyzed from 2013 through 2014. Results: Although musculoskeletal injuries were identified within the test populations, results showed fewer injuries for aeromedical evacuation populations compared to non–aeromedical evacuation counterparts. Conclusions: One contributing factor may be a potential under-reporting of musculoskeletal injuries resulting from the fear of being placed on limited flying status. As flyers, aeromedical evacuation personnel must undergo yearly medical examinations and complete training courses that emphasize proper lifting techniques and physical requirements necessary for the safe and efficient transport of patients on various platforms. These additional requirements may create a healthy worker effect, likely contributing to lower musculoskeletal injuries