We describe a new species of the genus Tylototriton from Ingyin Taung Mt., Mohnyin Township, Kachin State, Myanmar, based on morphological and molecular evidence. The new species is assigned to the subgenus Tylototriton s. str. and is clearly distinct from all known congeners by the following characters: medium body size; thin, long tail, lacking lateral grooves; rough skin; truncate snout; wide, protruding supratemporal bony ridges on head, beginning at anterior corner of orbit; weak, almost indistinct sagittal ridge; long, thin limbs, broadly overlapping when adpressed along body; distinct, wide, non-segmented vertebral ridge; 13 or 14 rib nodules; brown to dark-brown background coloration with dull orange-brown to yellowish-brown markings on labial regions, parotoids, rib nodules, whole limbs, vent, and ventral tail ridge. We also briefly discuss biogeography and species diversity of the genus Tylototriton in Myanmar.
Macrophages exist in most tissues and play a variety of functions in vertebrates. Teleost fish species are found in most aquatic environments throughout the world and are quite diverse for a group of vertebrate animals. Due to whole genome duplication and environmental adaptation, teleost monocytes/macrophages possess a variety of different functions and modulations compared with those of mammals. A deeper understanding of teleost monocytes/macrophages in the immune system will not only help develop teleost-specific methods of disease prevention but will also help improve our understanding of the various immune mechanisms in mammals. In this review, we summarize the differences in polarization and phagocytosis of teleost and mammalian macrophages to improve our understanding of the various immune mechanisms in vertebrates.
Why humans have large brains with higher cognitive abilities is a question long asked by scientists. However, much remains unknown, especially the underlying genetic mechanisms. With the use of a transgenic monkey model, we showed that human-specific sequence changes of a key brain development gene (primary microcephaly1, MCPH1) could result in detectable molecular and cognitive changes resembling human neoteny, a notable characteristic developed during human evolution.
This research aimed to provide evidence of a relationship between digit ratio and depression status in the cynomolgus monkey (Macaca fascicularis). In stable cynomolgus monkey social groups, we selected 15 depressed monkeys based on depressive-like behavioral criteria and 16 normal control monkeys. All animals were video recorded for two weeks, with the duration and frequency of the core depressive behaviors and 58 other behaviors in 12 behavioral categories then evaluated via behavioral analysis. Finger lengths from the right and left forelimb hands of both groups were measured by X-ray imaging. Finger length and digit ratio comparisons between the two groups were conducted using Student’s t-test. In terms of the duration of each behavior, significant differences emerged in “Huddling” and five other behavioral categories, including Ingestive, Amicable, Parental, Locomotive, and Resting. In addition to the above five behavioral categories, we found that depressed monkeys spent less time in parental and rubbing ‘ and forth behaviors than the control group. Furthermore, the 4th fingers were significantly longer in the left and right hands in the control group relative to the depressed monkeys. The second-to-fourth (2D:4D) digit ratio in the left and right forelimb hands was significantly lower in the control group than that in the depressed group. Our findings revealed significant differences in finger lengths and digit ratios between depressed monkeys and healthy controls, which concords with our view that relatively high fetal testosterone exposure may be a protective factor against developing depressive symptoms (or that low fetal testosterone exposure is a risk factor).
Protease inhibitors have been reported rarely from the leech Hirudinaria manillensis. In this study, we purified a novel protease inhibitor (bdellin-HM-2) with anticoagulant properties from H. manillensis. With a molecular weight of 1.4x104, bdellin-HM-2 was also characterized with three intra-molecular disulfide bridges at the N-terminus and multiple HHXDD and HXDD motifs at the C-terminus. cDNA cloning revealed that the putative nucleotide-encoding protein of bdellin-HM-2 contained 132 amino acids and was encoded by a 399 bp open reading frame (ORF). Sequence alignment showed that bdellin-HM-2 shared similarity with the “non-classical” Kazal-type serine protease inhibitors, but had no inhibitory effect on trypsin, elastase, chymotrypsin, kallikrein, factor XIIa (FXIIa), factor XIa (FXIa), factor Xa (FXa), thrombin, or plasmin. Bdellin-HM-2 showed anticoagulant effects by prolonging the activated partial thromboplastin time (aPTT), indicating a role in enabling H. manillensis to obtain a blood meal from its host. Our results suggest that bdellin-HM-2 may play a crucial role in blood-sucking in this leech species and may be a potential candidate for the development of clinical anti-thrombotic drugs.
Several previous studies have indicated that nest sanitation behavior is a general adaptation in altricial birds, with egg recognition capacity evolving as a specific response to interspecific brood parasitism (IBP). However, a recent study suggested an alternative hypothesis, concluding that conspecific brood parasitism (CBP) selects for egg rejection in thrushes, with IBP as a by-product. In the present study, we used a spectrophotometer to quantify egg coloration and egg mimicry and performed artificial parasitism experiments in the grey-backed thrush (Turdus hortulorum). We showed that individuals of this species rejected 100% of 12 foreign eggs, without IBP or CBP detected. In a review of previous studies, we also discuss possible explanations for the high egg rejection rate in the grey-backed thrush and suggest areas for future study.
A recently proposed taxonomic classification of extant ungulates sparked a series of publications that criticize the Phylogenetic Species Concept (PSC) claiming it to be a particularly poor species concept. These opinions reiteratively stated that (1) the two fundamental elements of the "PSC", i.e., monophyly and diagnosability, do not offer objective criteria as to where the line between species should be drawn; and (2) that extirpation of populations can lead to artificial diagnosability and spurious recognitions of species. This sudden eruption of criticism against the PSC is misleading. Problems attributed to the PSC are common to most approaches and concepts that modern systematists employ to establish species boundaries. The controversial taxonomic propositions that sparked criticism against the PSC are indeed highly problematic, not because of the species concept upon which they are based, but because no evidence (whatsoever) has become public to support a substantial portion of the proposed classification. We herein discuss these topics using examples from mammals. Numerous areas of biological research rest upon taxonomic accuracy (including conservation biology and biomedical research); hence, it is necessary to clarify what are (and what are not) the real sources of taxonomic inaccuracy.
Early brain development after birth is extremely dynamic, suggesting that potential functional changes occur during this period. In this study, the maximal electroshock seizure threshold (MEST) was used to explore the electrophysiological variation among three developmental stages in young mice (no more than 5 weeks old). The induced electroshock seizure (ES) behavior of early postnatal mice (1–2-weeks old) differed from that during weaning (3 weeks old) and early puberty (4–5-weeks old). Thus, we further explored their respective characteristic responses to the ES parameters. When the stimulation current (SC) was limited to 4.0 mA, only the 1–2-week-old mice were induced to exhibit ES behavior at voltages of 30 V and 40 V, indicating they were more sensitive to maximal electroshock seizure (MES) (response to lower voltage). Surprisingly, however, they showed substantially lower mortality than the older groups under higher voltage conditions (60, 100, 160, and 200 V), suggesting better tolerance to the SC. We also found that when the current limit decreased to 3.5 mA, the 4–5-week-olds mice exhibited stable ES behavior with low mortality, while for 3-week-olds mice, the SC limit required to be reduced to 1.5 mA. In conclusion, our findings showed that neural sensitivity to MES was significantly different in young mice before puberty. Thus, greater attention should be given to distinguishing the developmental period of mice, especially in electrophysiological examination.
Impacts of Quaternary environmental changes on mammal faunas of central Asia remain poorly understood due to a lack of geographically comprehensive phylogeographic sampling for most species. To help address this knowledge gap, we conducted the most extensive molecular analysis to date of the long-tailed ground squirrel (Urocitellus undulatus Pallas 1778) in Mongolia, a country that comprises the southern core of this species’ range. Drawing on material from recent collaborative field expeditions, we genotyped 128 individuals at 2 mitochondrial genes (cytochrome b and cytochrome oxidase I; 1 797 bp total). Phylogenetic inference supports the existence of two deeply divergent infraspecific lineages (corresponding to subspecies U. u. undulatus and U. u. eversmanni), a result in agreement with previous molecular investigations but discordant with patterns of range-wide craniometric and external phenotypic variation. In the widespread western eversmanni lineage, we recovered geographically-associated clades from the: (a) Khangai, (b) Mongolian Altai, and (c) Govi Altai mountain ranges. Phylogeographic structure in U. u. eversmanni is consistent with an isolation-by-distance model; however, genetic distances are significantly lower than among subspecies, and intra-clade relationships are largely unresolved. The latter patterns, as well as the relatively higher nucleotide polymorphism of populations from the Great Lakes Depression of northwestern Mongolia, suggest a history of range shifts into these lowland areas in response to Pleistocene glaciation and environmental change, followed by upslope movements and mitochondrial lineage sorting with Holocene aridification. Our study illuminates possible historical mechanisms responsible for U. undulatus genetic structure and contributes to a framework for ongoing exploration of mammalian response to past and present climate change in central Asia.
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