Human Plasma-like Medium Improves T Lymphocyte Activation.

T lymphocytes are critical for effective immunity, and the ability to study their behavior in vitro can facilitate major insights into their development, function, and fate. However, the composition of human plasma differs from conventional media, and we hypothesized that such differences could impact immune cell physiology. Here, we showed that relative to the medium typically used to culture lymphocytes (RPMI), a physiologic medium (human plasma-like medium; HPLM) induced markedly different transcriptional responses in human primary T cells and in addition, improved their activation upon antigen stimulation. We found that this medium-dependent effect on T cell activation is linked to Ca2+, which is six-fold higher in HPLM than in RPMI. Thus, a medium that more closely resembles human plasma has striking effects on T cell biology, further demonstrates that medium composition can profoundly affect experimental results, and broadly suggests that physiologic media may offer a valuable way to study cultured immune cells.

Chemically-mediated roostmate recognition and roost selection by Brazilian free-tailed bats (Tadarida brasiliensis).

BACKGROUND: The Brazilian free-tailed bat (Tadarida brasiliensis) is an exceptionally social and gregarious species of chiropteran known to roost in assemblages that can number in the millions. Chemical recognition of roostmates within these assemblages has not been extensively studied despite the fact that an ability to chemically recognize individuals could play an important role in forming and stabilizing complex suites of social interactions. METHODOLOGY/PRINCIPAL FINDINGS: Individual bats were given a choice between three roosting pouches: one permeated with the scent of a group of roostmates, one permeated with the scent of non-roostmates, and a clean control. Subjects rejected non-roostmate pouches with greater frequency than roostmate pouches or blank control pouches. Also, bats chose to roost in the roostmate scented pouches more often than the non-roostmate or control pouches. CONCLUSIONS/SIGNIFICANCE: We demonstrated that T. brasiliensis has the ability to chemically recognize roostmates from non-roostmates and a preference for roosting in areas occupied by roostmates. It is important to investigate these behaviors because of their potential importance in colony dynamics and roost choice.

Bridging cultural chasms between providers and HIV-positive Haitians in Palm Beach County, Florida.

This article discusses special challenges faced by HIV-positive Haitian immigrants, one of the groups targeted by the Care System Assessment Demonstration Project in Palm Beach County, Florida. The article examines the following issues: structural health care access barriers; language and literacy; health beliefs and practices and their intersection with Western medicine; health care-seeking attitudes, emotions, and behaviors; bridging cultural chasms; and lessons learned.

Ecology: 'Devil's gardens' bedevilled by ants.

'Devil's gardens' are large stands of trees in the Amazonian rainforest that consist almost entirely of a single species, Duroia hirsuta, and, according to local legend, are cultivated by an evil forest spirit. Here we show that the ant Myrmelachista schumanni, which nests in D. hirsuta stems, creates devil's gardens by poisoning all plants except its host plants with formic acid. By killing these other plants, M. schumanni provides its colonies with abundant nest sites--a long-lasting benefit as colonies can live for 800 years.