Host-Species Transferrin Receptor 1 Orthologs Are Cellular Receptors for Nonpathogenic New World Clade B Arenaviruses

The ability of a New World (NW) clade B arenavirus to enter cells using human transferrin receptor 1 (TfR1) strictly correlates with its ability to cause hemorrhagic fever. Amapari (AMAV) and Tacaribe (TCRV), two nonpathogenic NW clade B arenaviruses that do not use human TfR1, are closely related to the NW arenaviruses that cause hemorrhagic fevers. Here we show that pseudotyped viruses bearing the surface glycoprotein (GP) of AMAV or TCRV can infect cells using the TfR1 orthologs of several mammalian species, including those of their respective natural hosts, the small rodent Neacomys spinosus and the fruit bat Artibeus jamaicensis. Mutation of one residue in human TfR1 makes it a functional receptor for TCRV, and mutation of four residues makes it a functional receptor for AMAV. Our data support an in vivo role for TfR1 in the replication of most, if not all, NW clade B arenaviruses, and suggest that with modest changes in their GPs the nonpathogenic arenaviruses could use human TfR1 and emerge as human pathogens

South African HIV-1 subtype C transmitted variants with a specific V2 motif show higher dependence on α4β7 for replication.

CAPRISA, 2015.Abstract available in pdf

Private Property Rights and the Economics of Agricultural Land Preservation.

Concern over the magnitude and consequences of farmland conversions to developed uses has led to the adoption of agricultural land retention policy in every state of the nation. These policies have important consequences for the traditional rights of private property ownership in the U.S. The attenuation of private rights is argued to inhibit the efficient and equitable use of l and resources. In addition, the attenuation of property rights affects the ability of preservation programs to effectively enforce the trade-offs involved in retaining farmland . This study examines three alternative agricultural preservation policies for their effectiveness in retaining l and in agricultural uses, and their relative impact on the efficient and equitable use of resources. The framework for analysis combines the theories of property rights, neoclassical economics, public choice, and Austrian economics to provide a model for predicting the consequences of existing policy, the likelihood of policy reform, and recommendations for future policy. The major findings of this research are: (1) voluntary market-oriented programs, based on clearly-defined property rights, can be more effective at preserving l and in agriculture than direct regulatory programs, (2) both the type of regulation and the institutional arrangement for implementing the program are important factors in determining the effectiveness, efficiency and equity outcomes of the program, (3) regulations which inhibit or force l and transactions negatively affect the efficiency of a program, and (4) the degree of regulation tends to be inversely related to the equity of a program. As a result, the policy recommendations from this study include: (1) design preservation policy so as to provide incentives to owners of agricultural l and to voluntarily use the l and in agriculture; the cost of providing the incentive should be distributed among those who benefit from the program, (2) design policy to accommodate, rather than replace market forces, (3) maintain and enforce clearly-defined property rights so that benefits and costs of resource uses are efficiently and equitably distributed, and (4) determine the specific preservation goal and tailor the program to meet that goal.Ph.D.Agricultural economicsUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/161268/1/8702768.pd

Feasibility of a surplus wood energy industry for the state of Michigan

Among the various forms of renewable energy, the utilization of surplus wood poses a possible alternative energy supplement for the state of Michigan. Surplus wood is available from unutilized industrial wood wastes, logging residues, underutilized species, and cull trees. It has been conservatively estimated that during the next 30 years, 450 million t of surplus wood fiber in the state will be available for energy usage, capable of supplying approximately 1300 MW of installed electric generating capacity or around 4000 million 1/year of methanol. This paper examines the potential of producing liquid fuels and fuel wood for electric generation from surplus wood.The need to carefully remove surplus wood from forests has long been recognized by forest management experts. Proper removal of these materials will make the forests healthier, more productive and will simultaneously add to Michigan's energy supply. Until now, the lack of a market for this wood and the high cost of harvesting it, has resulted in over-exploitation of high quality trees, followed by a lack of forest management to regenerate high productivity stands.The growing and future opportunities of wood for energy can open markets which will allow for the intensive forest management practices that have been relatively ignored in the past. This paper discusses the expanding wood market and how it will directly and indirectly influence other economic markets.The paper concludes that the use of wood by-products from all wood related industries, and the utilization of more trees with improved forest management, can not only supplement the present energy sources, but can actually improve the state's forest productivity, thereby contributing to the overall economic viability of the concept.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25390/1/0000839.pd

Hepatitis B Awareness and Knowledge in Asian Communities in British Columbia

Background. Our study examined hepatitis B virus (HBV) awareness and knowledge in Asian communities in British Columbia (BC). Methods. A statistical random sample representation of Chinese, Korean, Filipino, South Asian, and Southeast Asian populations in Greater Vancouver was surveyed by telephone. Multiple logistic regression analysis was performed to identify predictors of HBV knowledge. Results. General awareness of HBV was reported in 78.8% (798/1013). HBV awareness was the highest in Chinese (89%) and Filipino (88%) populations and the lowest in the South Asian (56%) population. “Reasonable” knowledge of HBV was elicited in 76.8% (778/1013). Higher HBV knowledge was associated with younger age (p=0.014), higher education (p<0.0001), Chinese ethnicity (p<0.0001), and use of media (p=0.01) and Internet (p=0.024) for health information. Compared to the Chinese (OR = 1.0) population, “reasonable” knowledge of HBV was lower in Korean (OR = 0.3, 95% CI: 0.1–0.5), Filipino (OR = 0.3, 95% CI: 0.2–0.6), South Asian (OR = 0.3, 95% CI: 0.2–0.4), and Southeast Asian (OR = 0.3, 95% CI: 0.1–0.6) populations. 54.8% (555/1013) felt that HBV education was inadequate and 80.1% (811/1013) preferred HBV education in their native languages. Conclusion. Compared to the Chinese population, other Asian communities in BC have lower HBV awareness and knowledge. Public education should target older and less educated and Korean, Filipino, South Asian, and Southeast Asian populations in their native languages via media and Internet

Modest mutations convert human TfR1 into an efficient receptor for AMAV and TCRV.

<p>(A) The structure of the human TfR1 dimer is shown, oriented with the cell membrane at the bottom. The apical, protease-like, and helical domains are indicated in green, red, and yellow, respectively, on one monomer. The other monomer is shown in cyan. In the right panel, the TfR1 apical domain is enlarged; a loop comprising residues 202-212, implicated as a site of interaction with the GPs of NW clade B arenaviruses, is shown. The side chains of residues D204, K205, R208, V210, and Y211 are colored yellow. The image was rendered using PyMol <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1000358#ppat.1000358-DeLano1" target="_blank">[59]</a>. (B) Sequence alignment of residues 195 through 216 of human TfR1 with analogous sequences of the TfR1 orthologs of <i>Z. brevicauda</i> (ZbTfR1), <i>A. jamaicensis</i> (AjTfR1), and <i>N. spinosus</i> (NsTfR1). Variants of human TfR1 containing sequence from <i>Z. brevicauda</i> (zh1 and zh2), <i>A. jamaicensis</i> (ah2 through ah5), and <i>N. spinosus</i> (nh2, nh4, nh5, nh7, and nh8) TfR1 were generated based on this sequence alignment. Zb, Aj, and NsTfR1 sequences are shown in green, blue, and yellow, respectively. The right panel summarizes the entry data. ND = not determined. (C–E) HEK293T cells were transfected with plasmids encoding human, Zb, Aj, or NsTfR1 along with the zh variants (C), the ah variants (D), or the nh variants (E). The expression level of each TfR1 variant was assessed as in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1000358#ppat-1000358-g003" target="_blank">Figure 3</a>. In parallel, cells were infected with AMAV, TCRV, or VSV pseudoviruses. The expression levels of the various TfR1 orthologs were normalized to that of human TfR1 (α-flag, left panels), and infection levels were normalized to that of mock-transfected cells.</p

Host-animal orthologs of TfR1 support the entry of infectious AMAV and TCRV.

<p>HEK293 cells were transfected with plasmids encoding human TfR1, AjTfR1, or NsTfR1, and infectious viruses added at 36 hr post-transfection. Incubation was continued for 12 hr, and the cells were washed, fixed, and stained as described in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1000358#s4" target="_blank">Materials and Methods</a>.</p

AMAV and TCRV pseudovirus entry does not depend on human TfR1.

<p>HEK293T cells were infected with GTOV, AMAV, TCRV, or MACV pseudoviruses expressing GFP in the presence or absence of the indicated concentrations of an α-human TfR1 (BD Pharmingen) or a control (α-HLA) antibody (BD Pharmingen). Infection levels were assessed 48 hr later by measuring GFP expression by flow cytometry. Mean fluorescence values were normalized to that of cells infected in the absence of antibody. GFP mean fluorescence values for virus entry in the absence of antibody were 144.0, 89.7, 92.3, and 115.0 for GTOV, AMAV, TCRV, and MACV, respectively.</p

AMAV and TCRV pseudoviruses can use animal orthologs of TfR1.

<p>CHO cells ((A), left panel) were transfected with vector alone (mock) or plasmids encoding human, mouse, rat, feline, canine, <i>C. callosus</i> (Cc), <i>C. musculinus</i> (Cm), and <i>Z. brevicauda</i> (Zb) TfR1 orthologs. HEK293T cells ((B), right panel) were transfected with the same plasmids with the exception of the one encoding canine TfR1. Cell surface expression was determined 48 hr later by flow cytometry using an antibody directed against a flag tag present at the C-terminus of each ortholog. In parallel, aliquots of these cells were infected with AMAV, TCRV, or LCMV pseudoviruses. Infection levels were assessed as in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1000358#ppat-1000358-g002" target="_blank">Figure 2</a>. Expression levels of various TfR1 were normalized to that of human TfR1 (α-flag, top panels). Infection levels were normalized to that of mock-transfected cells.</p

AMAV and TCRV GPs bind and use the TfR1 orthologs of their respective host species.

<p>(A) HEK293T cells were transfected with plasmids encoding human TfR1 (hTfR1), <i>N. spinosus</i> TfR1 (NsTfR1), or <i>A. jamaicensis</i> TfR1 (AjTfR1). Cells were incubated 48 hr later with an α-flag antibody or Ig-fusion proteins comprising the truncated GP1 subunits <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1000358#ppat.1000358-Radoshitzky1" target="_blank">[32]</a> of AMAV and TCRV (AMAV GP1Δ-Ig and TCRV GP1Δ-Ig, respectively). The association of these proteins with cells was measured by flow cytometry. The data shown are representative of two independent experiments, duplicated in each assay, with similar results. Mean fluorescence values for TfR1 ortholog expression were 435, 380, and 458 for human, Ns, and AjTfR1, respectively. Mean fluorescence values for AMAV GP1Δ-Ig binding to transfected cells were 1.5, 597, and 1.6, and those for TCRV GPΔ-Ig binding were 3.7, 425, and 553 for human, Ns, and AjTfR1, respectively. (B) HEK293T cells were transfected with plasmids encoding human, ZbTfR1, NsTfR1, AjTfR1 orthologs or vector alone. Cell surface expression of the TfR1 orthologs was determined as in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1000358#ppat-1000358-g003" target="_blank">Figure 3</a>. Aliquots of these cells were infected with AMAV, TCRV, or VSV pseudoviruses, and infection levels were assessed as in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1000358#ppat-1000358-g002" target="_blank">Figure 2</a>. (C) An experiment similar to the one performed in (B), except CHO cells were used for transfection and infected with MACV, JUNV, GTOV, or VSV pseudoviruses. Expression levels of the various TfR1 orthologs were normalized to that of human TfR1 (α-flag, left panels). Infection levels were normalized to that of mock-transfected cells.</p