The complete mitochondrial genome of Myotis lucifugus (Chiroptera: Vespertilionidae)

First record of disk-footed bat Eudiscopus denticulus (Chiroptera, Vespertilionidae) from China and resolution of phylogenetic position of the genus

The disk-footed bat Eudiscopus denticulus(Osgood, 1932) is a rare species in Southeast Asia. During two chiropteran surveys in the summer of 1981 and 2019, eight and three small Myotis-like bats with distinct disk-like hindfeet were collected from Yunnan Province, China, respectively. External, craniodental, and phylogenetic evidence confirmed these specimens as E. denticulus, representing a new genus in China. The complete mitochondrial genome consistently showed robust support for E. denticulus as a basal lineage within Myotinae. The coding patterns and characteristics of its mitochondrial genome were similar to that of other published genomes fromMyotis. The echolocation signals of the newly collected individuals were analyzed. The potential distribution range of Eudiscopus in Southeast Asia inferred using the MaxEnt model indicated its potential occurrence along the southern border region of Yunnan, China.

The published complete mitochondrial genome of Eptesicus serotinus is a chimera of Vespertilio sinensis and Hypsugo alaschanicus (Mammalia: Chiroptera)

The mitogenome of Eptesicus serotinus (Serotine bat) was published in 2013 with GenBank accession number KF111725 and NCBI Reference Sequence number NC_022474. This sequence was placed with Vespertilio sinensis (Asian parti-colored bat) in a COI gene tree but with Hypsugo alashanicus (Alashanian pipistrelle) in a cytochrome b gene tree. Direct comparison of mitogenomes showed that 92.4% of this mitogenome is similar to Vespertilio sinensis, 5.9% to Hypsugo alaschanicus, and that 1.6% of the mitogenome could not be attributed to either species, or any other species. This mitogenome has been re-used in at least 17 phylogenies. Our findings suggest that mitogenomes are best verified with multiple gene trees, followed by direct comparison of sequences. We conclude that greater vigilance is warranted to ensure that problematic sequences do not enter the scientific record, and are not re-used in subsequent studies.

Identification of a prosurvival neuroprotective mitochondrial peptide in a mammalian hibernator

Hibernation requires the intricate regulation of physiological and biochemical adaptations to facilitate the decrease in metabolic rate and activation of prosurvival factors needed for winter survival. Mitochondria play important roles in eliciting these responses and in coordinating the required energy shifts. Herein, we report the presence of a novel mitochondrial peptide, s-humanin, in the hibernating 13-lined ground squirrel, Ictidomys tridecemlineatus. S-humanin was shown to have strong structural and sequence similarities to its human analogue, humanin-a powerful neuroprotective mitochondrial peptide. An assessment of the protein and gene expression levels of this peptide in ground squirrels revealed stark tissue-specific regulatory responses whereby transcript levels increased in brain cortex, skeletal muscle, and adipose tissues during hibernation, suggesting a protective torpor-induced activation. Accompanying peptide measurements found that s-humanin levels were suppressed in liver of torpid squirrels but enhanced in brain cortex. The enhanced transcript and protein levels of s-humanin in brain cortex suggest that it is actively involved in protecting delicate brain tissues and neuronal connections from hibernation-associated stresses. We propose that this squirrel-specific peptide is involved in modulating tissue-specific cytoprotective functions, expanding its role from human-specific neuroprotection to environmental stress protection. SIGNIFICANCE OF THE STUDY: Understanding the molecular mechanisms, which protect against oxidative stress in a model hibernator such as the ground squirrel, could be pivotal to the regulation of cytoprotection. This study expands on our knowledge of metabolic rate depression and could suggest a potential role for humanin therapy in neurodegenerative diseases.

The complete mitochondrial genome ofRhinolophus yunnanensis(Chiroptera: Vespertilionidae)

The mitochondrial genome of Rhinolophus yunnanensis (Chiroptera: Rhinolophidae) is a circular molecule of 16,865 bp in length with a base composition of 31.2% A, 24.3% T, 29.6% C, 14.9% G. In the control region of R. yunnanensis, the sequence of 5'-CAACGTATACACG-3′ repeats 18 times. Phylogenetic analyses indicate that R. yunnanensis is a sister clade to ((Rhinolophus sinicus sinicus + R. sinicus sinicus) + (R. macrotis + (R. pumilus + R. monoceros))).

The complete mitochondrial genome of the lesser sac-winged bat Saccopteryx leptura (Chiroptera: Emballonuridae) from Costa Rica

Here we present the first complete mitochondrial genome of the lesser sac-winged bat Saccopteryx leptura (Chiroptera: Emballonuridae) from Costa Rica, assembled from next-generation sequencing data. The mitogenome of Saccopteryx leptura measures 16,577 bp in length, and contains 13 protein-coding genes, 2 ribosomal RNA genes and 22 transfer RNA genes. A slight A + T bias was observed in the mitogenome of Saccopteryx leptura with an overall base composition of 31.5% A, 28.3% T, 25.8% C, and 14.2% G, and a GC content of 40.1%. The gene arrangement was identical to that of previously described bat mitogenomes.