The human immunodeficiency virus (HIV‐1) long terminal repeat (LTR) contains two binding sites for NF‐kappa B in close proximity to three binding sites for the constitutive transcription factor, Sp1. Previously, stimulation of the HIV enhancer in response to mitogens has been attributed to the binding of NF‐kappa B to the viral enhancer. In this report, we show that the binding of NF‐kappa B is not by itself sufficient to induce HIV gene expression. Instead, a protein‐protein interaction must occur between NF‐kappa B and Sp1 bound to an adjacent site. Cooperativity both in DNA binding and in transcriptional activation of NF‐kappa B and Sp1 was confirmed by electrophoretic mobility shift gel analysis, DNase footprinting, chemical cross‐linking and transfection studies in vivo. With a heterologous promoter, we find that the interaction of NF‐kappa B with Sp1 is dependent on orientation and position, and is not observed with other elements, including GATA, CCAAT or octamer. An increase in the spacing between the kappa B and Sp1 elements virtually abolishes this functional interaction, which is not restored when these sites are brought back into the same helical position. Several other promoters regulated by NF‐kappa B also contain kappa B in proximity to Sp1 binding sites. These findings suggest that an interaction between NF‐kappa B and Sp1 is required for inducible HIV‐1 gene expression and may serve as a regulatory mechanism to activate specific viral and cellular genes.

Urban vegetable gardens serve as sources of social, economic, and biodiversity conservation opportunities. Determining how gardens can be developed to enhance biodiversity and ecosystem services is important for organic food production. This study investigated the diversity of ant (Formicidae) species in relation to various garden attributes in three distinct gardening sites in Ann Arbor, MI. Further, predation experiments were conducted to explore the potential bio‐control services of commonly encountered ant species on Cabbage Looper moths (Trichoplusia ni) and Squash Bugs (Anasa tristis). Results indicated that community gardens have the capacity to support a multitude of ant species; 19 species from 12 genera were sampled. However, soil texture, intense tilling, and distance from less disturbed areas significantly reduces species richness. Less intensively tilled garden plots averaged nearly double the number of ant species collected in tractor‐tilled plots. Plots bordered by grass lawns and closer to wooded areas had significantly more ant species than plots surrounded by other garden plots. Predation experiments indicated that ants consume Cabbage Looper moth eggs and larvae, although predation on Squash Bugs was less common. Some of the species that demonstrated levels of predation are rare in gardens due to sensitivity to disturbance. Thus, reducing disturbance within and around gardens can promote ant biodiversity and beneficial predators leading to increased predation on garden pests.