Genetic Analysis of HIV-1 vpr Sequences from HIV-Infected Older Patients on Long-Term Antiretroviral Therapy.

BACKGROUND: Many HIV-infected individuals have achieved undetectable viral load and increased CD4 T cell counts due to the success of Antiretroviral Therapy (ART). However, HIV persists in resting T cells, monocytes/macrophages and other quiescent cells. Furthermore, the HIV- 1 vpr accessory gene may play an important role in the persistence of HIV in these infected patients. OBJECTIVES: Therefore, we characterized the HIV-1 vpr gene from PBMC DNA of 14 HIV-infected older patients on long-term ART with mostly undetectable viral load and increased CD4 T cell counts. METHODS: Peripheral Blood Mononuclear Cells (PBMC) were isolated from 14 HIV-infected individuals, followed by extraction of genomic DNA, amplification of HIV-1 vpr gene by polymerase chain reaction (PCR), cloning of vpr gene in TOPO vector and characterization of correct size recombinant inserts containing vpr genes. An average of 13 clones were sequenced from each patient, followed by sequence analysis by bioinformatic tools. RESULTS: Phylogenetic analysis of 182 vpr sequences demonstrated that the vpr sequences of each patient were well separated and discriminated from other patients' sequences and formed distinct clusters. The vpr sequences showed a low degree of viral heterogeneity, lower estimates of genetic diversity and about half of the patients' sequences were under positive selection pressure. While the majority of the vpr deduced amino acid sequences from most patients contained intact open reading frames, several sequences, mostly from two patients, had stop codons. Numerous patient-specific and common amino acid motifs were found in deduced vpr sequences. The functional domains required for vpr activity, including virion incorporation, nuclear import of pre-integration complex and cell cycle arrest, were generally conserved in most vpr sequences. Several of the known Cytotoxic T-lymphocytes (CTL) epitopes in vpr showed variation in our patients' sequences. CONCLUSION: In summary, a low degree of genetic variability, conservation of functional domains and variations in CTL epitopes were the features of vpr sequences from the 14 HIV-infected older patients with controlled viremia on long-term ART.

Sunflower (Helianthus annuus L.) Seed Hull Waste: Composition, Antioxidant Activity, and Filler Performance in Pectin-Based Film Composites.

Helianthus annuus L. seed hull is an abundant waste of the edible oil industry. To envisage potential applications of this waste, here, we aimed to analyze the chemical composition of milled sunflower hulls (SP), constituted mainly by 210 µm (51.4%) and 420 µm (27.6%) average mesh particle sizes. SP contained almost 30% of cellulose, 26.4% of lignin, 38.5% of neutral sugars, mainly hemicelluloses, and only 1.3% of proteins. The important lignin content and low pectin content (4.0% of uronic acids) present in SP were both ascribed to its low hydrophilic behavior and hydration capacity. Phenolic compounds were mostly proanthocyanidins (168 mg/100 g SP), with lower amounts of extractable (31.4 mg/100 g SP) phenolics (O-caffeoylquinic acid), all of them associated with the DPPH radical scavenging capacity (95 mg ascorbic acid equiv./100 g) and ferric reducing power (FRAP: 152 mg ascorbic acid equiv./100 g) shown by SP. Esterified ferulic acid (52.9 mg/100 g SP) was also found, mostly as monomers and trimers. SP of 53 µm particle size was then assayed as a filler (0, 5, 8, and 12% concentrations) in calcium low methoxyl pectin-based films, which showed antioxidant capacity (DPPH and FRAP assays) in an SP-concentration-dependent manner. SP showed homogeneous dispersion in composite films equilibrated at 57.7% relative humidity. Water content decreased while film thickness increased with SP concentration. When loaded at a 12% level, the presence of 53-µm SP decreased the water vapor permeability and increased the normal stress at film fracture. Sunflower hulls can then be applied to the development of active materials like 12% SP film, which can be proposed as a food slice antioxidant separator to be investigated in a future work.

Characterization of HIV-1 Envelope V3 Region Sequences from Virologically Controlled HIV-Infected Older Patients on Long Term Antiretroviral Therapy.

Although many HIV-infected patients have attained older age owing to the success of antiretroviral therapy (ART) in controlling viremia and increasing CD4 T cell counts, HIV continues to persist in several target cells. We have characterized 514 HIV-1 envelope V3 region sequences (94-96 amino acids [aa]) from 25 HIV-infected older patients' peripheral blood mononuclear cell DNA on long-term ART with controlled viremia (undetectable viral load) and improved CD4 T cell counts. Phylogenetic analysis revealed that the V3 region sequences of each patient formed distinct clusters that were well separated and discriminated from other patients' sequences. The coding potential of the V3 region, including several patient-specific amino acid motifs and functional domains, including the two cysteines sandwiching the V3 loop, the central GPGR motif with variation at one position in some sequences, the base GDIR motif, and the N-glycosylation sites were generally conserved. The patients' V3 region sequences contained amino acid motifs conferring affinity mostly for CCR5 coreceptor, suggesting R5 phenotype. There was a low degree of heterogeneity and lower estimates of genetic diversity in all 25 patients' V3 region sequences. Twelve of 25 patients' V3 region sequences were found to be under positive selection pressure. Analysis of the several cytotoxic T lymphocytes (CTL) epitopes showed variation, whereas some of known neutralizing antibodies (nAbs) epitopes showed conservation in patients' V3 region sequences. In conclusion, a low degree of genetic variability and maintenance of functional domains with R5 phenotypes, and variation in CTL and conservation of nAb epitopes were the hallmarks of V3 region sequences from our 25 virologically controlled HIV-infected older patients on long-term ART.

Husks of Zea mays as a potential source of biopolymers for food additives and materials' development.

Maize husks, an agricultural and industrial residue generated in a large volume, were investigated as a potential source of useful biopolymers. Thus, their chemical composition was firstly studied, after which two biopolymer products were obtained and characterized. Maize husks were dried and milled, obtaining a 210 µm-main particle size powder (MHP). It contained carotenes (4 mg/100 g), and exhibited antioxidant capacity (≈195 mg ascorbic acid/100 g MHP) coming also from extractable coumaric and cinnamic acids-derivatives (14 mg/100 g). A 31% of the MPH was water-soluble at room temperature, mainly constituted by fructose, glucose, and sorbitol of mesophylls' intracellular origin. The water insoluble fiber (WIF, ≈70%), which showed antioxidant capacity (≈25-33 mg ascorbic acid/100 g WIF), was almost entirely constituted by the cell wall biopolymers or alcohol insoluble residue (AIR) of the MPH, mostly arabinoxylans (≈26%) crosslinked by ferulic residues (18.6 mg/100 g MPH), and cellulose (26%). Low levels of pectins (5.5%) and lignin (7%) were found. Hence, a 1.25%-sulfur nanocellulose (NCC) was directly obtained with sulfuric acid (-15 mV Zeta-potential; 147 °C onset of thermal-degradation) without the necessity of previous delignification. On the other hand, a water soluble arabinoxylan enriched fraction (AX-EF) with pseudoplastic behavior in water and sensibility to calcium ions (≈3 Pa⋅s initial Newtonian-viscosity) was isolated by alkaline hydrolysis of diferulate bridges. Despite a 56% of crystallinity, NCC showed the highest water absorption capacity when compared to that of the AX-EF and AIR. Maize husks constitute an important source of biopolymers for development of materials and food additives/ingredients with relevant hydration and antioxidant properties.

Pectin-based composite film: Effect of corn husk fiber concentration on their properties.

Considering the polysaccharide composition and 32% of crystallinity of the water insoluble fiber extracted from corn husk (CHF) agricultural residue, its filler performance as water vapor permeability (WVP) and mechanical modifier in edible films based on commercial low methoxyl pectin (LMP) was evaluated (0, 1, 3, 5, 8% concentrations). The 53-µm-CHF carried phenolics and carotenes, and composites showed antioxidant capacity. Homogeneous films with a continuous LMP matrix were obtained. The 5%-CHF composite showed the highest surface contact angle (44°) and tensile strength, without change in elongation, while WVP was decreased in the 3-8% CHF-LMP-films. The latter was ascribed to the CHF-filler crystallinity whereas the improvement in mechanical performance and contact angle was attributed to a CHF-interconnected network formed at 5%-CHF critical concentration. Corn husk residue can be utilized as a source of fibers for material development. Composites with enhanced performance can be an antioxidant strategy at food interfaces.