Nonhuman primate models are increasingly used in the screening of candidate AIDS vaccine and immunization strategies for advancement to large-scale human trials. The predictive value of such macaque studies is largely dependent upon the fidelity of the model system in mimicking human immunodeficiency virus (HIV) type 1 infection in terms of viral transmission, replication, and pathogenesis. Herein, we describe the efficient mucosal transmission of a CCR5-specific chimeric simian/human immunodeficiency virus, SHIV SF162P3 . Female rhesus macaques were infected with SHIV SF162P3 after a single atraumatic application to the cervicovaginal mucosa. The disease course of SHIV SF162P3 -infected monkeys is similar and as varied as natural HIV infection in terms of viral replication, gradual loss of CD4؉ peripheral blood mononuclear cells, and the development of simian AIDS-defining opportunistic infections. The SHIV SF162P3 /macaque model should facilitate direct preclinical assessment of HIV vaccine strategies in addition to antiviral compounds directed towards envelope target cell interactions. Furthermore, this controlled model provides the setting to investigate immunologic responses and putative host-specific susceptibility factors that alter viral transmission and subsequent disease progression.
Infection of rhesus macaques with chimeric simian-human immunodeficiency viruses (SHIV) is an established method to study AIDS pathogenesis and is increasingly used to assess the efficacy of vaccine and antiviral candidates. For these reasons, a detailed understanding of those molecular determinants, which confer pathogenic potential to SHIV viruses, should assist in both rational experimental design and interpretation of results. In this report, we describe the development and in vivo characterization of a pathogenic molecular clone, SHIVSF33A2, which contains an envelope sequence derived from the CXCR4-dependent isolate, HIV-1SF33. Proviral DNA, amplified from a rhesus macaque infected with the pathogenic isolate SHIVSF33A, was substituted into the corresponding region of the parental, nonpathogenic SHIVSF33 genome creating the molecular clone SHIVSF33A2. Coreceptor specificity of SHIVSF33A2 was determined to be CXCR4 specific. Naive rhesus macaques were productively infected after a single exposure to cell-free SHIVSF33A2 by either the intravenous (IV) or intravaginal (IVAG) routes. Animals infected with SHIVSF33A2 suffered a severe loss of peripheral CD4+ T cells and high acute plasma viremia with development of simian AIDS 9 months after inoculation. Sequence analysis identified 25 discreet amino acid changes within the V1-V5 regions of the envelope protein when compared with the nonpathogenic parental virus. These data indicate that domains within the HIV-1 envelope protein are sufficient to define pathogenic potential in the context of the SIVmac239 genome.
Tea (Camellia sinensis L.) is one of the most popular beverage crops. Among tea production constraints, weed is one of the detrimental factors in tea productions in Ethiopia. For the possibility of developing weed management method determining the dominant and abundant weed species is highly important to identify and prioritize the most noxious and prevalent weed that associated with tea production in the country. Weed flora survey was conducted in two different tea estate farms Wushwush and Gumero tea plantations in 2019/20 cropping seasons. The field survey was done according to the quantitative survey method by using 1m 2 quadrate size. Weeds present in each quadrate were counted and identified to species level. Weed abundance, dominance, frequency and similarity index was determined at two tea producing locations. A total of 63 weed species were identified from assessed tea plantation farms. The result revealed that 61.3% and 71.9% of broad leaf weed was recorded at Wushwush and Gumaro tea plantation, respectively. Only, two (6.5%) parasitic weed species were recorded at Wushwush. The most prevalent and abundant weed species at Wushwush was Ageratum conyzoides followed by Hydrocotyle americana, whereas, H. americana was the most dominant species at Gumero tea plantation. Generally, from survey results, the weed flora composition was similar in both assessed areas, as its similarity index resulted above 70%. Hence, similar weed management methods should be recommended for both locations.
Infection of rhesus macaques with chimeric simian-human immunodeficiency viruses (SHIV) is an established model to study acquired immunodeficiency syndrome (AIDS) pathogenesis. Such a controlled system allows for detailed analysis of the molecular determinants of viral pathogenesis in addition to studying host-specific immune responses that modulate disease progression. Furthermore, the use of a pathogenic molecular clone affords the opportunity to study both viral evolution within a host and to examine the generation of tissue specific variants. In this report we describe viral diversification within tissues of two rhesus macaques infected intravenously with the CXCR4-specific molecular clone SHIVSF33A2. Heteroduplex tracking analysis (HTA) was used to determine the complexity of viral DNA within distinct lymphoid tissues. Not surprising, heterogeneity of the proviral quasispecies in tissues obtained during the acute infection was limited. However, tissues obtained at necropsy harbored a more diverse and often different population of env variants. As the inoculating virus is a molecular clone, the variants generated are likely due to the presence of tissue specific selective forces rather than a founder's effect.
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