Publications by authors named "Chandran K"

There is an urgent need for monoclonal antibody (mAb) therapies that broadly protect against Ebola virus and other filoviruses. The conserved, essential interaction between the filovirus glycoprotein, GP, and its entry receptor Niemann-Pick C1 (NPC1) provides an attractive target for such mAbs but is shielded by multiple mechanisms, including physical sequestration in late endosomes. Here, we describe a bispecific-antibody strategy to target this interaction, in which mAbs specific for NPC1 or the GP receptor-binding site are coupled to a mAb against a conserved, surface-exposed GP epitope.

View Article and Find Full Text PDF

This study mainly evaluated the effectiveness of ozonation toward the enhancement of the removal efficiencies of antibiotic-resistant bacteria (ARB), pB10 plasmid transfer, and pB10 plasmids under different pH and suspended solids (SS) and humic acid concentrations. First, chlorination was tested as a reference disinfection process. Chlorination at a very high dose concentration of Cl2 (75 mg L(-1)) and a long contact time (10 min) were required to achieve approximately 90% ARB and pB10 plasmid transfer removal efficiencies.

View Article and Find Full Text PDF

The recent Ebola virus outbreak in western Africa highlights the need for novel therapeutics that target Ebola virus and other filoviruses. Filoviruses require processing by host cell-derived cysteine cathepsins for productive infection. Here we report the generation of a focused library of cysteine cathepsin inhibitors and subsequent screening to identify compounds with potent activity against viral entry and replication.

View Article and Find Full Text PDF

Filoviruses are the causative agents of an increasing number of disease outbreaks in human populations, including the current unprecedented Ebola virus disease (EVD) outbreak in western Africa. One obstacle to controlling these epidemics is our poor understanding of the host range of filoviruses and their natural reservoirs. Here, we investigated the role of the intracellular filovirus receptor, Niemann-Pick C1 (NPC1) as a molecular determinant of Ebola virus (EBOV) host range at the cellular level.

View Article and Find Full Text PDF

Pathogenic New World hemorrhagic fever mammarenaviruses (NWM) utilize Glycoprotein 1 (GP1) to target the apical domain of the human transferrin receptor (hTfR) for facilitating cell entry. However, the conservation between their GP1s is low. Considering this and the slow evolutionary progression of mammals compared to viruses, therapeutic targeting of hTfR provides an attractive avenue for cross-strain inhibition and diminishing the likelihood of escape mutants.

View Article and Find Full Text PDF

In 2016, the order Mononegavirales was emended through the addition of two new families (Mymonaviridae and Sunviridae), the elevation of the paramyxoviral subfamily Pneumovirinae to family status (Pneumoviridae), the addition of five free-floating genera (Anphevirus, Arlivirus, Chengtivirus, Crustavirus, and Wastrivirus), and several other changes at the genus and species levels. This article presents the updated taxonomy of the order Mononegavirales as now accepted by the International Committee on Taxonomy of Viruses (ICTV).

View Article and Find Full Text PDF

We report the complete draft genome sequence of Cryptococcus albidus var. albidus, an oleaginous yeast, which can utilize various organic carbon sources for lipid synthesis. Availability of this genome will help elucidate factors driving lipid accumulation in C.

View Article and Find Full Text PDF

Previous efforts to identify cross-neutralizing antibodies to the receptor-binding site (RBS) of ebolavirus glycoproteins have been unsuccessful, largely because the RBS is occluded on the viral surface. We report a monoclonal antibody (FVM04) that targets a uniquely exposed epitope within the RBS; cross-neutralizes Ebola (EBOV), Sudan (SUDV), and, to a lesser extent, Bundibugyo viruses; and shows protection against EBOV and SUDV in mice and guinea pigs. The antibody cocktail ZMapp™ is remarkably effective against EBOV (Zaire) but does not cross-neutralize other ebolaviruses.

View Article and Find Full Text PDF

Unlabelled: The filovirus surface glycoprotein (GP) mediates viral entry into host cells. Following viral internalization into endosomes, GP is cleaved by host cysteine proteases to expose a receptor-binding site (RBS) that is otherwise hidden from immune surveillance. Here, we present the crystal structure of proteolytically cleaved Ebola virus GP to a resolution of 3.

View Article and Find Full Text PDF

The goal of this study was to investigate the responses in the physiology, microbial ecology and gene expression of nitrifying bacteria to imposition of and recovery from Cr(VI) loading in a lab-scale nitrification bioreactor. Exposure to Cr(VI) in the reactor strongly inhibited nitrification performance resulting in a parallel decrease in nitrate production and ammonia consumption. Cr(VI) exposure also led to an overall decrease in total bacterial concentrations in the reactor.

View Article and Find Full Text PDF

Unlabelled: Ebola virus (EBOV) makes extensive and intricate use of host factors in the cellular endosomal/lysosomal pathway to release its genome into the cytoplasm and initiate infection. Following viral internalization into endosomes, host cysteine proteases cleave the EBOV fusion glycoprotein (GP) to unmask the binding site for its intracellular receptor, the cholesterol transporter Niemann-Pick C1 (NPC1). GP-NPC1 interaction is required for viral entry.

View Article and Find Full Text PDF

Filoviruses (Ebola and Marburg) cause severe hemorrhagic fever. There are five species of ebolavirus; among these, the Ebola (Zaire) and Sudan viruses (EBOV and SUDV, respectively) are highly pathogenic and have both caused recurring, large outbreaks. However, the EBOV and SUDV glycoprotein (GP) sequences are 45% divergent and thus antigenically distinct.

View Article and Find Full Text PDF
Article Synopsis
  • Biological factors determining the host range and spillover of Ebola virus (EBOV) and other filoviruses are still not well understood.
  • Research shows that African straw-colored fruit bats (Eidolon helvum) are resistant to EBOV due to a specific amino acid change in the NPC1 receptor, which weakens the virus's ability to bind to the receptor.
  • The study identifies the NPC1 receptor as a key genetic factor influencing filovirus susceptibility in bats, indicating that some variations in NPC1 may help bats adapt and reduce the severity of filovirus infections.
View Article and Find Full Text PDF

Autotrophic nitrification in biological nitrogen removal systems has been shown to be sensitive to the presence of heavy metals in wastewater treatment plants. Using transcriptase-quantitative polymerase chain reaction (RT-qPCR) data, we examined the effect of copper on the relative expression of functional genes (i.e.

View Article and Find Full Text PDF

Inflammatory and invasive breast cancers are aggressive and require better understanding for the development of new treatments and more accurate prognosis. Here, we detected high expression of PPARα in human primary inflammatory (SUM149PT) and highly invasive (SUM1315MO2) breast cancer cells, and tissue sections of human breast cancer. PPARα ligands are clinically used to treat dyslipidemia.

View Article and Find Full Text PDF
Article Synopsis
  • Over the next few decades, nitrous oxide (N2O) is expected to significantly impact climate change and ozone depletion, primarily produced by nitrifying microbes in wastewater treatment through the biochemical breakdown of nitrite and nitric oxide.
  • A mathematical model was developed to explore how alternative nitrogen redox reactions affect N2O formation, utilizing genomic data from eight ammonia- and nitrite-oxidizing bacteria (AOB and NOB).
  • The model revealed that N2O production was significantly reduced (by 60%) when including specific oxidation reactions in AOB, while no significant N2O production was shown from NOB, indicating a lack of contribution during nitrification.
View Article and Find Full Text PDF

Heavy metals can inhibit nitrification, a key process for nitrogen removal in wastewater treatment. The transcriptional responses of amoA, hao, nirK, and norB were measured in conjunction with specific oxygen uptake rate (sOUR) for nitrifying enrichment cultures exposed to different metals (Ni(II), Zn(II), Cd(II), and Pb(II)). There was significant decrease in sOUR with increasing concentrations for Ni(II) (0.

View Article and Find Full Text PDF

As nitrogen discharge limits are becoming more stringent, short-cut nitrogen systems and tertiary nitrogen polishing steps are gaining popularity. For partial nitritation or nitritation-denitritation systems, anaerobic ammonia oxidation (anammox) polishing may be feasible to remove residual ammonia and nitrite from the effluent. Nitrogen polishing of mainstream nitritation-denitritation system effluent via anammox was studied at 25°C in a fully anoxic moving bed bioreactor (MBBR) (V = 0.

View Article and Find Full Text PDF

Background: The current Ebola virus (EBOV) outbreak has highlighted the troubling absence of available antivirals or vaccines to treat infected patients and stop the spread of EBOV. The EBOV glycoprotein (GP) plays critical roles in the early stage of virus infection, including receptor binding and membrane fusion, making it a potential target for the development of anti-EBOV drugs. We report the identification of 2 novel EBOV inhibitors targeting viral entry.

View Article and Find Full Text PDF

Unlabelled: Hantaviruses cause hemorrhagic fever with renal syndrome (HFRS) in the Old World and a highly fatal hantavirus cardiopulmonary syndrome (HCPS) in the New World. No vaccines or antiviral therapies are currently available to prevent or treat hantavirus disease, and gaps in our understanding of how hantaviruses enter cells challenge the search for therapeutics. We performed a haploid genetic screen in human cells to identify host factors required for entry by Andes virus, a highly virulent New World hantavirus.

View Article and Find Full Text PDF

This work describes the development of an intermittently aerated pilot-scale process (V = 0.45 m(3) ) operated for optimized efficient nitrogen removal in terms of volume, supplemental carbon and alkalinity requirements. The intermittent aeration pattern was controlled using a strategy based on effluent ammonia concentration set-points.

View Article and Find Full Text PDF

Unlabelled: Recent work demonstrated that the Niemann-Pick C1 (NPC1) protein is an essential entry receptor for filoviruses. While previous studies focused on filovirus entry requirements of NPC1 in vitro, its roles in filovirus replication and pathogenesis in vivo remain unclear. Here, we evaluated the importance of NPC1, and its partner in cholesterol transport, NPC2, by using a mouse model of Ebolavirus (EBOV) disease.

View Article and Find Full Text PDF

It has been reported that a directional change from anoxic to aerobic conditions is a common trigger for nitrous oxide (N2 O) production by ammonia oxidizing bacteria (AOB). By extension, during anoxic-aerobic cycling, post-anoxic dissolved oxygen (DO) concentrations might likely play a role in the magnitude of N2 O emissions observed. The overall goal of this study was to determine the impact of three select post-anoxic DO concentrations (0.

View Article and Find Full Text PDF

Despite interest in characterizing nitrous oxide (N2O) emissions from wastewater treatment plants (WWTPs) in several parts of the globe, there are few studies in tropical zones. This study focus on the contribution of the scientific knowledge of anthropogenic nitrogen greenhouse gas emissions to climate change in tropical countries, investigating factors controlling N2O emissions in a non-biological nitrogen removal municipal WWTP. In terms of operational parameters, dissolved oxygen (DO) concentrations displayed a biphasic impact on N2O production and emission, with the highest emission at DO of 2.

View Article and Find Full Text PDF

Necrotic cell death triggers a range of biological responses including a strong adaptive immune response, yet we know little about the cellular pathways that control necrotic cell death. Inhibitor studies suggest that proteases, and in particular cathepsins, drive necrotic cell death. The cathepsin B-selective inhibitor CA-074-Me blocks all forms of programmed necrosis by an unknown mechanism.

View Article and Find Full Text PDF