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Rare CD4 T cells that contain HIV under antiretroviral therapy represent an important barrier to HIV cure1–3, but the infeasibility of isolating and characterizing these cells in their natural state has led to uncertainty about whether they possess distinctive attributes that HIV cure-directed therapies might exploit. Here we address this challenge using a microfluidic technology that isolates the transcriptomes of HIV-infected cells based solely on the detection of HIV DNA. HIV-DNA+ memory CD4 T cells in the blood from people receiving antiretroviral therapy showed inhibition of six transcriptomic pathways, including death receptor signalling, necroptosis signalling and antiproliferative Gα12/13 signalling. Moreover, two groups of genes identified by network co-expression analysis were significantly associated with HIV-DNA+ cells. These genes (n = 145) accounted for just 0.81% of the measured transcriptome and included negative regulators of HIV transcription that were higher in HIV-DNA+ cells, positive regulators of HIV transcription that were lower in HIV-DNA+ cells, and other genes involved in RNA processing, negative regulation of mRNA translation, and regulation of cell state and fate. These findings reveal that HIV-infected memory CD4 T cells under antiretroviral therapy are a distinctive population with host gene expression patterns that favour HIV silencing, cell survival and cell proliferation, with important implications for the development of HIV cure strategies.

Treatment of HIV infection with either antiretroviral (ARV) therapy or neutralizing monoclonal antibodies (NAbs) leads to a reduction in HIV plasma virus. Both ARVs and NAbs prevent new rounds of viral infection, but NAbs may have the additional capacity to accelerate the loss of virus-infected cells through Fc gamma receptor (FcγR)-mediated effector functions, which should affect the kinetics of plasma-virus decline. Here, we formally test the role of effector function in vivo by comparing the rate and timing of plasma-virus clearance in response to a single-dose treatment with either unmodified NAb or those with either reduced or augmented Fc function. When infused into viremic simian HIV (SHIV)-infected rhesus macaques, there was a 21% difference in slope of plasma-virus decline between NAb and NAb with reduced Fc function. NAb engineered to increase FcγRIII binding and improve antibody-dependent cellular cytotoxicity (ADCC) in vitro resulted in arming of effector cells in vivo, yet led to viral-decay kinetics similar to NAbs with reduced Fc function. These studies show that the predominant mechanism of antiviral activity of HIV NAbs is through inhibition of viral entry, but that Fc function can contribute to the overall antiviral activity, making them distinct from standard ARVs.

Determination of endogenous levels of jasmonic acid (JA) is essential, as it plays a pivotal role in the physiological processes during a plant’s life cycle. A high performance thin layer chromatography (HPTLC) method was developed for the detection and quantification of JA in leaf extracts of medicinal plant, Stevia rebaudiana (Bertoni) Bertoni. The separation was achieved using the solvents ethyl acetate–benzene (1:1, v/v) as the mobile phase, followed by scanning and quantification at 295 nm. Densitometric analysis of leaf extract resulted in compact spots for JA at Rf = 0.45 ± 0.02. The linear regression analysis showed good relationship with r value. The recovery rate of JA indicated good reproducibility and repeatability of the assay. The statistical analysis proved the reproducibility of the method; therefore, it can be employed for routine quantification of JA in different tissue samples of S. rebaudiana and may also be extrapolated to other biological samples.

Stevia rebaudiana (Bertoni) produces low calorie sweeteners, steviol glycosides (SGs) - stevioside and rebaudioside-A. Varying spore concentrations of P. indica were applied to S. rebaudiana grown in vitro and in the greenhouse to examine the effect on plant growth and synthesis of SGs. Symbiotic association of P. indica showed plant growth promotion and higher SGs content. The transcription profiles of eight key genes of the SGs biosynthetic pathway also showed strong upregulation. The results show that the symbiotic effect of P. indica can be utilized to achieve plant growth enhancement in S. rebaudiana along with increased production of SGs.

Rare mutations have been proposed to restrict the development of broadly neutralizing antibodies against HIV-1, but this has not been explicitly demonstrated. We hypothesized that such rare mutations might be identified by comparing broadly neutralizing and non-broadly neutralizing branches of an antibody-developmental tree. Because sequences of antibodies isolated from the fusion peptide (FP)-targeting VRC34-antibody lineage suggested it might be suitable for such rare mutation analysis, we carried out next-generation sequencing (NGS) on B cell transcripts from donor N123, the source of the VRC34 lineage, and functionally and structurally characterized inferred intermediates along broadly neutralizing and poorly neutralizing developmental branches. The broadly neutralizing VRC34.01 branch required the rare heavy-chain mutation Y33P to bind FP, whereas the early bifurcated VRC34.05 branch did not require this rare mutation and evolved less breadth. Our results demonstrate how a required rare mutation can restrict development and shape the maturation of a broad HIV-1-neutralizing antibody lineage.

The herb Stevia rebaudiana Bertoni is an important sugar substitute due to the presence of steviol glycosides-mainly stevioside and rebaudioside-A. These compounds possess antioxidant activity with industrial importance. The fungus Piriformospora indica has been used to improve medicinally important biomolecules, growth and secondary metabolite content in plants. The soil bacterium Azotobacter chroococcum has also been reported to possess plant growth promoting ability. The present study was undertaken to test the ability of P. indica (Pi) and A. chroococcum (Az), alone and in combination to improve the growth, antioxidant activity and steviol glycoside (SG) content of in vitro S. rebaudiana plantlets. Inoculation with Pi or Az alone showed enhancement in all these characters compared with non-inoculated plantlets. Combined inoculation with Pi and Az further enhanced these traits.

Medicinal plants have been used widely for their bioactive ingredients as they are highly potent and have least side effects. This has led to a surge in demand for medicinal plants for producing higher quantity and good quality bioactive compounds. Symbiotic association of microorganisms with plants has been shown to affect the production and quality of active ingredients. However, the effect is not consistent and is seen to vary under different microbial associations. This chapter elucidates the studies on microbial symbiosis with medicinal plants and the effect of this interaction on medicinally important bioactive ingredients. The role of both nutritional and non-nutritional pathways in this interaction has also been discussed.