Phytohormones play important roles in germination, blossom, senescence, abscission of plants by a series of signal transduction and molecular regulation. The purpose of this research was to investigate the influence of root restriction (RR) cultivation on plant endogenous hormone variation tendency at different growth stages in diverse organs or tissues. 'Muscat Hamburg' (Vitis 'Muscat of Alexandria' × Vitis 'Trollinger') grapevine was used as test material. High Performance Liquid Chromatography (HPLC) was used to quantify hormone levels, qRT-PCR was used to quantify the expression of genes related to hormone biosynthesis pathway, and determined parameters of growth and photosynthetic, aiming to investigate the influence of root restriction on the formation and metabolism of phytohormones, as well as the degree of correlation between phytohormones and plant growth and photosynthetic intensity under root restriction. By measuring the photosynthetic rate of leaves at the stages of core-hardening, veraison and maturity, it was found that root restriction could reduce most photosynthetic parameters. The results also revealed that RR treatment increased abscisic acid (ABA), salicylic acid (SA), zeatin riboside (ZR), N6-(delta 2-isopentenyl)-adenine nucleoside (iPR) concentrations, while reduced auxin (IAA), 3-indolepropionic acid (IPA), 3-indolebutyric acid (IBA), gibberellin A3 (GA3), zeatin (ZT), N6-(delta 2-Isopentenyl)-adenine (iP), kinetin (KT), jasmonic acid (JA) and methyl jasmonate (MeJA) concentrations in most organs and at most developmental stages. RT-qPCR was carried out to further explore the effect of root restriction on genes expression of ABA, SA and IAA biosynthesis pathways at molecular level. Meanwhile, through correlation analysis, we found that different phytohormones contributed differently to physiological indicators, there existed strong correlation of ABA, KT, MeJA, iPR, SA, JA with leaf photosynthesis, GA3, IBA, ZR, IAA, ZT with fruit quality. In addition, we also found that the shoot growth related parameters were closely correlated with JA, IPA and iP. To sum up, our results suggested that RR treatment could significantly increase soluble solid content, regulate the growth and photosynthesis of grapevine, by affecting the biosynthesis of phytohormones. It could further prove that root restriction was a feasible technique to ameliorate the phenomenon of low quality in grape berry in southern China.
If we have any hope of achieving a cure for HIV infection, close attention to the cell types capable of getting infected with HIV is necessary. Of these cell types, astrocytes are the most ideal cell type for the formation of such a reservoir. These are long-lived cells with a very low turnover rate and are found in the brain and the gastrointestinal tract. Although astrocytes are evidently resistant to infection of cell-free HIV in vitro, these cells are efficiently infected via cell-tocell contact by which immature HIV virions bud off lymphocytes and have the ability to directly bind to CXCR4, triggering the process of fusion in the absence of CD4. In this review, we closely examine the evidence for HIV infection of astrocytes in the brain and the mechanisms for viral entry and regulation in this cell type, and discuss an approach for controlling this viral reservoir. Keywords: Astrocyte, CXCR4, endocytosis, HIV, latency, reservoir.
Objective To investigate the impact of the polymorphisms of CCR5, CCR2 and SDF1 on HIV-1 heterosexual transmission. Methods The polymorphisms of CCR5, CCR2 and SDF1 were displayed by PCR/RFLP and carefully assessed as influential factors on HIV-1 heterosexual transmission. Results The deletion of CCR5 in the coding region (CCR5Δ32) wasn′t found in Han Chinese in this cohort, but the frequency of CCR5Δ32 was 6.5%(6/92) in Uygur people (no allele of CCR5Δ32/Δ32). The data didn′t sound the role of CCR5Δ32 in HIV-1 heterosexual transmission in China. On the other hand, a higher frequency of CCR2-64I allele was observed in HIV-1 uninfected partners who were heterosexually exposed to HIV-1 positive index partners than those infected with HIV-1 ( P =0.164). However, a higher frequency of SDF1-3′A allele was found in HIV-1 positive index individuals with HIV-1 positive partners than those with negative partners ( P =0.163). Conclusion Heterozygous allele of CCR5 (CCR5 +/Δ32) is not substantially supposed to influence HIV-1 heterosexual transmission in China. CCR2-64I may play a role in protecting from HIV-1 heterosexual transmission, but SDF1-3′A seems to be a risk factor.
Abstract: Lipid-based nanoparticles (NPs) with a small amount of surface-chelated nickel (Ni-NPs) were developed to easily formulate the human immunodeficiency virus (HIV) his-tagged Tat (his-Tat) protein, as well as to formulate and co-deliver two HIV antigens (his-p24 and his-Nef) on one particle. Female BALB/c mice were immunized by subcutaneous injection with his-Tat/Ni-NP formulation (1.5 µg his-Tat/mouse) and control formulations on day 0 and 14. The day 28 anti-Tat specific immunoglobulin G titer with his-Tat/Ni-NPs was significantly greater than that with Alum/his-Tat. Furthermore, splenocytes from his-Tat/Ni-NP-immunized mice secreted significantly higher IFN-γ than those from mice immunized with Alum/his-Tat. Although Ni-NPs did not show better adjuvant activity than Tat-coated anionic NPs made with sodium dodecyl sulfate (SDS/NPs), they were less toxic than SDS/NPs. The initial results indicated that co-immunization of mice using his-p24/his-Nef/Ni-NP induced greater antibody response compared to using Alum/his-p24/his-Nef. Co-delivery of two antigens using Ni-NPs also increased the immunogenicity of individual antigens compared to delivery of a single antigen by Ni-NPs. In conclusion, Ni-NPs are an efficient delivery system for HIV vaccines including both single antigen delivery and multiple antigen co-delivery. Keywords: nanoparticle, nickel, HIV, antigen co-delivery, vaccine
The Tat protein of the human immunodeficiency virus (HIV) has been implicated in the neuropathogenesis of HIV infection. This is the earliest protein to be produced by the proviral DNA in the infected cell. The protein not only drives the production and replication of the virus but is also actively released from the cell and then interacts with cell surface receptors of other uninfected cells in the brain leading to cellular dysfunction. It may also be taken up by these cells and can then activate a number of host genes. The Tat protein is highly potent and has the unique ability to travel along neuronal pathways. It can also easily cross the blood brain barrier. Importantly, its production is not impacted by the use of antiretroviral drugs once the proviral DNA has been formed. This chapter reviews the pleomorphic actions of Tat protein in relation to its effects on the nervous system.
To study the distribution of human immunodeficiency virus (HIV)-1 genotypes in major prevalent regions of China and to illustrate the relationship between HIV-1 subtypes and mother-to-child transmission in a retrospective cohort.HIV-1 gag p17 and env C2-V4 region were amplified by nested-polymerase chain reaction (nPCR) and the sequences were obtained by sequencing gag nPCR products or clones of env gene.60 HIV-1 positive individuals were subject to typing for gag p17 and 69 for env C2-V4 region. Single clade was only found in Henan (subtype B') and Xinjiang (subtype C), and subtypes C and E were demonstrated in Yunnan. These regions represented most of the HIV-1 infections in China. Multiple subtypes (A, B, C, E, etc.) were found in Beijing and Shanghai, where HIV infections were still in low level. The sequences of subtype C were less diversive in Xinjiang (p17: 0.0192 +/- 0.0078, C2-V4: 0.0455 +/- 0.0145) than in Yunnan (p17: 0.0279 +/- 0.0102, C2-V4: 0.0482 +/- 0.0171), but all of them clustered in "C" branch in phylogenetic trees. Trafficking of subtype C from Yunnan to Xinjiang was found but had already been reported by others. Compared to subtype C, subtype E was quite divergent (p17: 0.0473 +/- 0.0105, C2-V4: 0.1114 +/- 0.0112) in Yunnan, but no recombination was found in the C2-V4 region of env gene. Highe divergence of subtype B' was found in Henan and the peripheral provinces (p17: 0.0381 +/- 0.0101, C2-V4: 0.0691 +/- 0.0166), which might be attributed to the early epidemics of HIV-1 in these areas (early 1990's). In maternal-child cohort, subtypes B (7/21), C (11/21), E (1/21) and undefined types (2/21) were identified in non-transmitting HIV-1 positive mothers, while only subtype B (7/11) and C (4/11) appeared in transmitting HIV-1 positive mothers. The rate of transmission was 53.8% (7/13) in mothers infected with subtype B and 30.8% (4/13) in those infected with subtype C, but with no significant difference (P = 0.196). The imbalancing distribution of subtypes might be explained by the fact that transfusion or illegal blood would increased mother-to-child transmission on HIV-1 and most of mothers with clade B were infected by illegal blood transfusion in this cohort. In addition, most of the maternal-child pair's sequences clustered in gag or env phylogenetic trees but only a few did disperse among the unrelated patients because children were older (>/= 4 years).The characteristics of HIV-1 clade's distribution differed over most parts of China but no difference was demonstrated between subtype B and C in mother-to-child transmission on HIV-1.
HIV reservoir in the brain represents a major barrier for curing HIV infection. As the most abundant, long-lived cell type, astrocytes play a critical role in maintaining the reservoir; however, the mechanism of infection remains unknown. Here, we determine how viral transmission occurs from HIV-infected lymphocytes to astrocytes by cell-to-cell contact.Human astrocytes were exposed to HIV-infected lymphocytes and monitored by live-imaging, confocal microscopy, transmission and three-dimensional electron microscopy. A panel of receptor antagonists was used to determine the mechanism of viral entry.We found that cell-to-cell contact resulted in efficient transmission of X4 or X4R5-using viruses from T lymphocytes to astrocytes. In co-cultures of astrocytes with HIV-infected lymphocytes, the interaction occurred through a dynamic process of attachment and detachment of the two cell types. Infected lymphocytes invaginated into astrocytes or the contacts occurred via filopodial extensions from either cell type, leading to the formation of virological synapses. In the synapses, budding of immature or incomplete HIV particles from lymphocytes occurred directly onto the membranes of astrocytes. This cell-to-cell transmission could be almost completely blocked by anti-CXCR4 antibody and its antagonist, but only partially inhibited by anti-CD4, ICAM1 antibodies.Cell-to-cell transmission was mediated by a unique mechanism by which immature viral particles initiated a fusion process in a CXCR4-dependent, CD4-independent manner. These observations have important implications for developing approaches to prevent formation of HIV reservoirs in the brain.
Abstract Endogenous plant hormones play important roles in germination, blossom, senescence, abscission of plants by a series of signal transduction and molecular regulation. The purpose of this research was to investigate the influence of root restriction (RR) cultivation on plant hormones variation tendency at different growth stages in diverse organs or tissues, ‘Muscat Hamburg’ (Vitis ‘Muscat of Alexandria’ × Vitis ‘Trollinger’) grapevine was used as test material. High Performance Liquid Chromatography (HPLC) was used to quantify hormone levels, aiming to investigate the influence of root restriction on the formation and transportation of plant hormones. The results revealed that RR treatment increased abscisic acid, salicylic acid, zeatin riboside, N6-(delta 2-isopentenyl)-adenine nucleoside concentrations, while reduced auxin, 3-indolepropionic acid, 3-indolebutyric acid, gibberellin A 3 , zeatin, N6-(delta 2-Isopentenyl)-adenine, kinetin, jasmonic acid and methyl jasmonate concentrations. To sum up, our results suggested that RR treatment could initiate stress responses via up-regulating abscisic acid and salicylic acid contents while down-regulating auxin and kinetin contents, resulting in the changes of fruit appearance and improvement of berry quality.
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