Do bats use guano and urine stains to find new roosts? Tests with three group-living bats

Many animals use social cues to find refuges. Bats can find roosts using the echolocation and social calls of conspecifics, but they might also use scent cues, a possibility which is less studied. The entrances of bat roosts are often marked by guano and urine, providing possible scent cues. We conducted eight experiments to test whether bats use the scent of guano and urine to find potential roosts. In field experiments, we tested if Molossus molossus (velvety free-tailed bats) in Panama and Eptesicus fuscus (big brown bats) in Ohio would investigate artificial roost boxes that were scented with guano and urine more often than a paired unscented control. We did not detect any difference in flights near the scented versus unscented roosts, and we detected only one entrance into any artificial roost (scented). In six captive experiments, we tested for the attraction of Desmodus rotundus (common vampire bats) and Molossus molossus to areas scented with guano and urine, under several conditions. Results were mixed, but overall suggested that the scent of guano and urine does not act as a strong lure for the tested bat species. We suggest that further tests of olfaction-based roost choice in bats should manipulate existing scent cues on familiar roosts.

High levels of HMGB1 in plasma may be due to ex vivo cell necrosis

BACKGROUND

High mobility group box 1 protein (HMGB1) is considered an important biological marker during inflammation and malignancies. Here, we evaluated sample handling and effects of ex vivo necrosis on HMGB1 levels.

MATERIALS AND METHODS

Plasma samples were obtained from healthy volunteers (n=14) simulating the standard laboratory conditions, overnight incubations and harsh treatment. HMGB1 levels were evaluated by ELISA or western blot. Additionally, levels of hemoglobin, hemolysis index and lactate dehydrogenase were measured.

RESULTS

Plasma levels of HMGB1 were 9-fold increased in samples stored overnight at room temperature, as compared to those processed directly. The rapid centrifugation prevented the increase of HMGB1 in stored samples. Hemoglobin, hemolysis index and lactate dehydrogenase concentrations showed significant correlations with HMGB1 levels.

CONCLUSION

Handling of blood samples is important for the accurate estimation of systemic HMGB1. We propose that all samples with high HMGB1 concentrations should be evaluated for markers of ex vivo necrosis.

In vivo clearance of hepatitis C virus nonstructural 3/4A-expressing hepatocytes by DNA vaccine-primed cytotoxic T lymphocytes

A key question in the development of a therapeutic vaccine against hepatitis C virus (HCV) is whether vaccine-primed T cells enter the liver and eliminate HCV-expressing hepatocytes. In the absence of an infectious small-animal model, we evaluated liver homing of vaccine-primed T cells in mice with transient hepatic transgene expression of the HCV nonstructural 3/4A (NS3/4A) protein. We found that T cells primed by transdermal DNA-based vaccination entered the liver and cleared NS3/4A-expressing hepatocytes in transiently transgenic CD8(+/+) mice but not in CD8(-/-) mice. Hence, peripherally primed NS3/4A-specific CD8(+) T cells home to the liver and clear HCV protein-expressing hepatocytes.

Tactile/kinesthetic stimulation effects on preterm neonates

Tactile/kinesthetic stimulation was given to 20 preterm neonates (mean gestational age, 31 weeks; mean birth weight, 1,280 g; mean time in neonatal intensive care unit, 20 days) during transitional ("grower") nursery care, and their growth, sleep-wake behavior, and Brazelton scale performance was compared with a group of 20 control neonates. The tactile/kinesthetic stimulation consisted of body stroking and passive movements of the limbs for three, 15-minute periods per day for a 10 days. The stimulated neonates averaged a 47% greater weight gain per day (mean 25 g v 17 g), were more active and alert during sleep/wake behavior observations, and showed more mature habituation, orientation, motor, and range of state behavior on the Brazelton scale than control infants. Finally, their hospital stay was 6 days shorter, yielding a cost savings of approximately $3,000 per infant. These data suggest that tactile/kinesthetic stimulation may be a cost effective way of facilitating growth and behavioral organization even in very small preterm neonates.