HIV-1 tat transactivator recruits p300 and CREB-binding protein histone acetyltransferases to the viral promoter

In cells infected with HIV type 1 (HIV-1), the integrated viral promoter is present in a chromatin-bound conformation and is transcriptionally silent in the absence of stimulation. The HIV-1 Tat protein binds to a stem-loop structure at the 5' end of viral mRNA and relieves this inhibition by inducing a remodeling of the nucleosome arrangement downstream of the transcription-initiation site. Here we show that Tat performs this activity by recruiting to the viral long terminal repeat (LTR) the transcriptional coactivator p300 and the closely related CREB-binding protein (CBP), having histone acetyltransferase (HAT) activity. Tat associates with HAT activity in human nuclear extracts and binds to p300 and CBP both in vitro and in vivo. Integrity of the basic domain of Tat is essential for this interaction. By a quantitative chromatin immunoprecipitation assay we show that the delivery of recombinant Tat induces the association of p300 and CBP with the chromosomally integrated LTR promoter. Expression of human p300 in both human and rodent cells increases the levels of Tat transactivation of the integrated LTR. These results reinforce the evidence that p300 and CBP have a pivotal function at both cellular and viral promoters and demonstrate that they also can be recruited by an RNA-targeted activator. Additionally, these findings have important implications for the understanding of the mechanisms of HIV-1 latency and reactivation.

Preparation and antibacterial evaluation of urinary balloon catheter

Prolonged use of indwelling urinary catheters in bed-ridden patients lead to a variety of Urinary Tract Infections (UTI). The present study deals with the surface treatment of ready-made urinary catheters so as to render them antibacterial in nature. Catheters were treated with varying percentages of iodine in conjunction with natural rubber latex, and their iodide ion release pattern and antibacterial behaviour were evaluated.

Antigenic variation in Foot and Mouth Disease Virus type Asia 1 isolates circulated during 1993-95 in India

The antigenic variation in Foot and Mouth Disease Virus (FMDV) is very high. The effective strategy to control the Foot and Mouth Disease (FMD) in India which is a habitat of four serotypes O, A, C and Asia 1, is by regular vaccination, using the vaccine strain most suitable for the local situation. India is an endemic country with the disease being widely distributed. Selection of vaccine strain should therefore need the information on the circulating viruses. Asia 1 causes the second largest number of disease outbreaks in India. As there is no information available with respect to the extent of antigenic variation in FMDV type Asia 1, we have studied FMDV isolates from vaccinated and unvaccinated animals from different parts of the country and compared their relationship with Asia 1 vaccine virus. The immunogenic, hypervariable region of viral protein 1 (VP1) gene was amplified by RT-PCR and sequenced. Analysis of sequence data showed that the viruses from two field outbreaks of Southern India were closely related to each other when compared to the isolate from the North and all the three isolates are away from the vaccine virus.

Fetal growth in maternal anaemia

The effect of maternal iron deficiency anemia on fetal growth was studied in 54 anaemic (haemoglobin < 11.0 g/dl) mothers. Twenty-two mothers served as controls (haemoglobin > or = 11.0 g/dl). All the women had singleton live births at term gestation. The maternal iron status was assessed by serum ferritin estimation. The birth weight, head circumference, chest circumference, mid-arm circumference, and crown heel length were significantly low in infants born to women with moderate (haemoglobin 6.1 +/- 8.5 g/dl) and severe anaemia (haemoglobin < or = 6.0 g/dl), in comparison to infants born to non-anaemic women. Similarly, birth weight, mid-arm circumference, and crown-heel length were significantly low in infants of women with depleted iron stores (serum ferritin < 10 micrograms/l) than in infants of women with serum ferritin levels of 20 micrograms/l or more. All indices of fetal growth showed linear relationships with maternal haemoglobin, as well as with serum ferritin. The growth retarding effect of maternal anaemia was more on fetal birth weight and mid-arm circumference than on other anthropometric indices of the newborn.

Fetal iron status in maternal anemia

Hemoglobin, serum iron, transferrin saturation and ferritin were measured on paired maternal and cord blood samples in 54 anemic (hemoglobin < 110 g/L) and 22 non-anemic (hemoglobin > or = 110 g/L) pregnant women at term gestation. The levels of hemoglobin, serum iron, transferrin saturation and ferritin were significantly low in the cord blood of anemic women, suggesting that iron supply to the fetus was reduced in maternal anemia. The linear relationships of these parameters with both maternal hemoglobin and maternal serum ferritin indicated that the fetus extracted iron in amounts proportional to the levels available in the mother. Infants of mothers with moderate and severe anemia had significantly lower cord serum ferritin levels and hence poor iron stores at birth. It is concluded that iron deficiency anemia during pregnancy adversely affects the iron endowment of the infant at birth.