Topic
Murina
About: Murina is a research topic. Over the lifetime, 95 publications have been published within this topic receiving 1453 citations.
Papers published on a yearly basis
Papers
TL;DR: Large signal bandwidths facilitate highly accurate target localization in terms of both range and angle estimation and can thus be interpreted as an adaptation to foraging in the highly cluttered environment of the forest understorey.
Abstract: Echolocation signal design in nine syntopic vespertilionid bats from the Malaysian rain forest understorey was studied. Four species of Kerivoula, two species of Phoniscus (Kerivoulinae) and three species of Murina (Murininae) all emitted calls that are typical of species that glean insects from surfaces: broadband, frequency-modulated (FM) calls of low intensity and short duration. However, calls were highly distinctive in the use of very large bandwidths (range: 89–123 kHz) and extremely high frequencies (start frequency 152–180 kHz; end frequency 43–86 kHz). Furthermore, calls were produced in groups of 2–15 at very high pulse repetition rates (37–105 Hz). The functional significance of these characteristics with respect to foraging strategy is discussed. Large signal bandwidths facilitate highly accurate target localization in terms of both range and angle estimation and can thus be interpreted as an adaptation to foraging in the highly cluttered environment of the forest understorey. The use of high frequencies so far in excess of those seen in other FM gleaning bats of the same size is less easily explained, but may represent a mechanism by which these species distinguish prey items using echolocation alone, without recourse to visual or auditory cues. Species exhibited differences in echolocation parameters, particularly the end frequency and the number of calls per group of calls. The two subfamilies differed from each other in multivariate space derived from echolocation parameters; calls of the Murininae were of lower frequency than the Kerivoulinae and were typically produced in smaller groups or singly. Within the subfamilies there was considerable overlap between species of Murina, but the Kerivoula spp. were clearly distinct from one another but not from the two Phoniscus spp.
86 citations
TL;DR: It is shown that despite possessing enhanced killing, AMs from naive Src TKO mice did not demonstrate enhanced inflammatory responses to P. murina, and results indicate that M2a AMs are potent effector cells against P. Murina.
Abstract: We have recently reported that mice deficient in the myeloid Src-family tyrosine kinases Hck, Fgr, and Lyn (Src triple knockout [TKO]) had augmented innate lung clearance of Pneumocystis murina that correlated with a higher ability of alveolar macrophages (AMs) from these mice to kill P. murina. In this article, we show that despite possessing enhanced killing, AMs from naive Src TKO mice did not demonstrate enhanced inflammatory responses to P. murina. We subsequently discovered that both AMs and lungs from P. murina-infected Src TKO mice expressed significantly greater levels of the M2a markers RELM-α and Arg1, and the M2a-associated chemokines CCL17 and CCL22 than did wild-type mice. IL-4 and IL-13, the primary cytokines that promote M2a polarization, were not differentially produced in the lungs between wild-type and Src TKO mice. P. murina infection in Src TKO mice resulted in enhanced lung production of the novel IL-1 family cytokine IL-33. Immunohistochemical analysis of IL-33 in lung tissue revealed localization predominantly in the nucleus of alveolar epithelial cells. We further demonstrate that experimental polarization of naive AMs to M2a resulted in more efficient killing of P. murina compared with untreated AMs, which was further enhanced by the addition of IL-33. Administration of IL-33 to C57BL/6 mice increased lung RELM-α and CCL17 levels, and enhanced clearance of P. murina, despite having no effect on the cellular composition of the lungs. Collectively, these results indicate that M2a AMs are potent effector cells against P. murina. Furthermore, enhancing M2a polarization may be an adjunctive therapy for the treatment of Pneumocystis.
85 citations
TL;DR: Data support previous recognition of multiple species in the genus and indicate that P. murina is a phylogenetic species as well.
Abstract: Pneumocystis is a fungal genus that contains multiple species. One member of the genus that has not been formally analysed for its phylogenetic relationships and possible species status is the Pneumocystis found in laboratory mice, Pneumocystis murina sp. nov. (type strain ATCC PRA-111(T)=CBS 114898(T)), formerly known as Pneumocystis carinii f. sp. muris. To advance research in this area, approximately 3000 bp of additional DNA sequence were obtained from the locus encoding rRNAs. This sequence and others were used to determine genetic distances between P. murina and other members of the genus. These distances indicated that P. murina DNA is most similar to that of the species of Pneumocystis found in laboratory rats. Nevertheless, P. murina is at least as diverged from these other Pneumocystis species as species in other fungal genera are from each other. The 18S rRNA gene sequence divergence exhibited by P. murina could not be ascribed to accelerated evolution of this gene as similar levels of divergence were observed at seven other loci. When five genes were used to construct phylogenetic trees for five Pneumocystis taxa, including P. murina, all the trees had the same topology, indicating that genes do not flow among these taxa. The gene trees were all strongly supported by statistical tests. When sequences from the rRNA-encoding locus were used to estimate the time of divergence of P. murina, the results indicated that P. murina is as old as the mouse. Taken together, these data support previous recognition of multiple species in the genus and indicate that P. murina is a phylogenetic species as well.
80 citations
TL;DR: A new species of Murina of the suilla- type is described from the Hkakabo Razi Landscape, Kachin, Upper Myanmar, an area that is currently being nominated as a World Heritage Site and high cryptic diversity of the genus Murina in Southeast Asia is highlighted.
Abstract: A new species of Murina of the suilla- type is described from the Hkakabo Razi Landscape, Kachin, Upper Myanmar, an area that is currently being nominated as a World Heritage Site. The new species is a small vespertilionid, with a forearm length of 29.6 mm, and is very similar to M. kontumensis , which was recently described from Vietnam. However, it is distinguishable by a combination of external and craniodental morphology and genetics. The DNA Barcode reveals that the new species clusters sisterly to M. kontumensis but with a genetic distance of 11.5%. A single known specimen of the new species was collected from a lowland forest area in the plains of the Hkakabo Razi landscape, south-eastern Himalaya. Additional information on ecology, echolocation, and conservation are included. The high cryptic diversity of the genus Murina in Southeast Asia, as well as the Hkakabo Razi Landscape being a bat diversity hotspot, is highlighted.
71 citations
TL;DR: Results indicate that TLR2 plays a major role in the innate immune response to P. murina, leading to the nuclear translocation of NF-κB and the production of proinflammatory cytokine tumor necrosis factor alpha and chemokine macrophage inflammatory protein 2.
Abstract: The innate immune response to Pneumocystis infection is not well understood. In this study, normal C57BL/6 mouse alveolar macrophages were found to respond to Pneumocystis murina organisms through Toll-like receptor 2 (TLR2), leading to the nuclear translocation of NF-κB and the production of proinflammatory cytokine tumor necrosis factor alpha (TNF-α) and chemokine macrophage inflammatory protein 2 (MIP-2). P. murina stimulation of normal alveolar macrophages from C57BL/6 mice resulted in increased TLR2 transcription but not increased TLR4 transcription. In gain-of-function studies with HEK293 cells expressing TLR2 or TLR4, only TLR2 was found to stimulate an NF-κB response to P. murina. TNF-α and MIP-2 production in response to P. murina by mouse alveolar macrophages was inhibited by a monoclonal antibody that specifically blocked the ligand-binding ability of TLR2. Alveolar macrophages from TLR2 knockout (TLR2−/−) mice showed little increase in TNF-α and MIP-2 mRNA levels upon P. murina stimulation. An in vivo study showed that TLR2−/− mice challenged with P. murina had reduced cytokine responses. These results indicate that TLR2 plays a major role in the innate immune response to P. murina.
68 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 3 |
| 2020 | 2 |
| 2019 | 2 |
| 2018 | 2 |
| 2017 | 3 |
| 2016 | 5 |