In vivo bioluminescence imaging of Ca signalling in the brain of Drosophila

Many different cells' signalling pathways are universally regulated by Ca(2+) concentration [Ca(2+)] rises that have highly variable amplitudes and kinetic properties. Optical imaging can provide the means to characterise both the temporal and spatial aspects of Ca(2+) signals involved in neurophysiological functions. New methods for in vivo imaging of Ca(2+) signalling in the brain of Drosophila are required for probing the different dynamic aspects of this system. In studies here, whole brain Ca(2+) imaging was performed on transgenic flies with targeted expression of the bioluminescent Ca(2+) reporter GFP-aequorin (GA) in different neural structures. A photon counting based technique was used to undertake continuous recordings of cytosolic [Ca(2+)] over hours. Time integrals for reconstructing images and analysis of the data were selected offline according to the signal intensity. This approach allowed a unique Ca(2+) response associated with cholinergic transmission to be identified by whole brain imaging of specific neural structures. Notably, [Ca(2+)] transients in the Mushroom Bodies (MBs) following nicotine stimulation were accompanied by a delayed secondary [Ca(2+)] rise (up to 15 min. later) in the MB lobes. The delayed response was sensitive to thapsigargin, suggesting a role for intra-cellular Ca(2+) stores. Moreover, it was reduced in dunce mutant flies, which are impaired in learning and memory. Bioluminescence imaging is therefore useful for studying Ca(2+) signalling pathways and for functional mapping of neurophysiological processes in the fly brain.     

The tail of the Ordovician fish Sacabambaspis

The tail of the earliest known articulated fully skeletonized vertebrate, the arandaspid Sacabambaspis from the Ordovician of Bolivia, is redescribed on the basis of further preparation of the only specimen in which it is most extensively preserved. The first, but soon discarded, reconstruction, which assumed the presence of a long horizontal notochordal lobe separating equal sized dorsal and ventral fin webs, appears to have considerable merit. Although the ventral web is significantly smaller than the dorsal one, the presence of a very long notochordal lobe bearing a small terminal web is confirmed. The discrepancy in the size of the ventral and dorsal webs rather suggests that the tail was hypocercal, a condition that would better accord with the caudal morphology of the living agnathans and the other jawless stem gnathostomes.     

Growth patterns in brooding dinosaurs reveals the timing of sexual maturity in non-avian dinosaurs and genesis of the avian condition

The timing of sexual maturation in non-avian dinosaurs is not known. In extant squamates and crocodilians it occurs in conjunction with the initial slowing of growth rates as adult size is approached. In birds (living dinosaurs) on the other hand, reproductive activity begins well after somatic maturity. Here we used growth line counts and spacing in all of the known brooding non-avian dinosaurs to determine the stages of development when they perished. It was revealed that sexual maturation occurred well before full adult size was reached-the primitive reptilian condition. In this sense, the life history and physiology of non-avian dinosaurs was not like that of modern birds. Palaeobiological ramifications of these findings include the potential to deduce reproductive lifespan, fecundity and reproductive population sizes in non-avian dinosaurs, as well as aid in the identification of secondary sexual characteristics.     

A comparative study of leptospirosis and dengue in Thai children

Background

Leptospirosis is an emerging zoonosis that is often under-recognized in children and commonly confused with dengue in tropical settings. An enhanced ability to distinguish leptospirosis from dengue in children would guide clinicians and public health personnel in the appropriate use of limited healthcare resources.

Methodology/Principal Findings

We conducted a prospective, hospital-based, study of children with acute febrile illnesses and dengue in Thailand. Among the children without dengue, we identified those with leptospirosis using anti-leptospira IgM and microscopic agglutination titers in paired acute and convalescent blood samples. We then performed a case-control comparison of symptoms, signs, and clinical laboratory values between children with leptospirosis and dengue.In a semi-rural region of Thailand, leptospirosis accounted for 19% of the non-dengue acute febrile illnesses among children presenting during the rainy season. None of the children with leptospirosis were correctly diagnosed at the time of hospital discharge, and one third (33%) were erroneously diagnosed as dengue or scrub typhus. A predictive model to distinguish pediatric leptospirosis from dengue was generated using three variables: the absolute neutrophil count, plasma albumin, and aspartate aminotransferase levels in the first 72 hours of illness.

Conclusions/Significance

Unrecognized leptospirosis can be a significant cause of “dengue-like” febrile illness in children. Increased awareness of pediatric leptospirosis, and an enhanced ability to discriminate between leptospirosis and dengue early in illness, will help guide the appropriate use of healthcare resources in often resource-limited settings.     

Mexican body mass index values in the late-19th-century American West

No research has been done on the body mass index values of the 19th-century Mexican population. This paper introduces a new data source of 19th-century Mexican male inmates in American prisons and finds that the majority of Mexican body mass was in the normal range (18.5-24.9). Few Mexicans were underweight or obese by modern standards. Body mass varied little (0-0.9 units) by occupations possibly because criminals probably came from the lower end of the socioeconomic distribution; however, it did vary with crimes for which inmates were incarcerated.     

Intractable mixtures and the origin of life

Attempts to model the spontaneous chemistry which presumably preceded the origin of life on Earth commonly result in the production of intractably complex mixtures of organic compounds. It is, therefore, difficult to understand how any kind of evolutionary process might have begun. A number of potential solutions to this well-known and frustrating problem have been offered in the literature over the years. The present contribution briefly reviews and evaluates some of the more promising possibilities.