Bronchoalveolar lavage for diagnosis of tuberculosis infection in elephants.

Tuberculosis (TB) has been known to affect elephants for thousands of years. It was put into spotlight when few circus elephants were diagnosed carrying Mycobacterium (M.) tuberculosis. Because of the zoonotic risk and high susceptibility to M. tuberculosis, periodic testing was enacted since, in captive breeding programmes. Presently, trunk wash is the recommended diagnostic procedure for TB. Trunk wash, however, puts the operator at risk, has low sensitivity, and is prone to contamination. Here, bronchoalveolar lavage is described for the first time for TB diagnosis in elephants. Bronchial, trunk and mouth fluids were investigated using bacterial culture, M. tuberculosis complex (MTC)-specific real-time quantitative PCR (qPCR) and mycobacterial genus-specific qPCR for overall presence of mycobacteria or mycobacterial DNA including bacteria or DNA of closely related genera, respectively, in 14 elephants. Neither bacteria of the MTC nor their DNA were identified in any of the elephants. Yet, 25% of the cultures grew non-tuberculous mycobacteria (NTM) or closely related bacterial species. Furthermore, 85% of the samples contained DNA of NTM or closely related bacterial genera. This finding might explain continued false-positive results from various serological tests. From a zoonotic point of view, bronchoalveolar lavage is safer for the testing personal, has higher probability of capturing MTC and, through PCR, identifies DNA NTM in elephants. Yet, necessary endoscopic equipment, animal sedation and access to a TB reference laboratory might pose challenging requirements in remote conditions in some elephant range countries.

Study of Age-Dependent Structural and Functional Changes of Mitochondria in Skeletal Muscles and Heart of Naked Mole Rats (Heterocephalus glaber).

Morphometric analysis of mitochondria in skeletal muscles and heart of 6- and 60-month-old naked mole rats (Heterocephalus glaber) revealed a significant age-dependent increase in the total area of mitochondrial cross-sections in studied muscle fibers. For 6- and 60-month-old animals, these values were 4.8 ± 0.4 and 12.7 ± 1.8%, respectively. This effect is mainly based on an increase in the number of mitochondria. In 6-month-old naked mole rats, there were 0.23 ± 0.02 mitochondrial cross-sections per µm2 of muscle fiber, while in 60-month-old animals this value was 0.47 ± 0.03. The average area of a single mitochondrial cross-section also increased with age in skeletal muscles - from 0.21 ± 0.01 to 0.29 ± 0.03 µm2. Thus, naked mole rats show a drastic enlargement of the mitochondrial apparatus in skeletal muscles with age due to an increase in the number of mitochondria and their size. They possess a neotenic type of chondriome accompanied by specific features of mitochondrial functioning in the state of oxidative phosphorylation and a significant decrease in the level of matrix adenine nucleotides.

Fruit bats (Pteropodidae) fuel their metabolism rapidly and directly with exogenous sugars.

Previous studies reported that fed bats and birds mostly use recently acquired exogenous nutrients as fuel for flight, rather than endogenous fuels, such as lipids or glycogen. However, this pattern of fuel use may be a simple size-related phenomenon because, to date, only small birds and bats have been studied with respect to the origin of metabolized fuel, and because small animals carry relatively small energy reserves, considering their high mass-specific metabolic rate. We hypothesized that approximately 150 g Egyptian fruit bats (Rousettus aegyptiacus Pteropodidae), which are more than an order of magnitude heavier than previously studied bats, also catabolize dietary sugars directly and exclusively to fuel both rest and flight metabolism. We based our expectation on the observation that these animals rapidly transport ingested dietary sugars, which are absorbed via passive paracellular pathways in the intestine, to organs of high energy demand. We used the stable carbon isotope ratio in exhaled CO(2) (delta(13)C(breath)) to assess the origin of metabolized substrates in 16 Egyptian fruit bats that were maintained on a diet of C3 plants before experiments. First, we predicted that in resting bats delta(13)C(breath) remains constant when bats ingest C3 sucrose, but increases and converges on the dietary isotopic signature when C4 sucrose and C4 glucose are ingested. Second, if flying fruit bats use exogenous nutrients exclusively to fuel flight, we predicted that delta(13)C(breath) of flying bats would converge on the isotopic signature of the C4 sucrose they were fed. Both resting and flying Egyptian fruit bats, indeed, directly fuelled their metabolism with freshly ingested exogenous substrates. The rate at which the fruit bats oxidized dietary sugars was as fast as in 10 g nectar-feeding bats and 5 g hummingbirds. Our results support the notion that flying bats, irrespective of their size, catabolize dietary sugars directly, and possibly exclusively, to fuel flight.