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Characterisation of Cutaneous Wound Healing Process in Naked Mole RatsFatima, Iqra January 2022 (has links)
Being the longest-lived rodent, naked mole-rats (NMR; Heterocephalus glaber) are
an exceptional model for biogerontological research. However, unlike other
rodents, not much is known about their wound healing process. To investigate that,
full-thickness wounds were created in the back skin of naked mole rats. Our initial
data confirmed that wound closure in NMR skin was achieved primarily by reepithelialization
and granulation tissue formation, with only ~26% wound
contraction, making them an excellent model to study human cutaneous wound
healing. Similar to mice and human skin, changes in wound epithelial tongue
included progressive enlargement of wound epithelium, increased proliferation and
changes in the expression pattern of epidermal markers including K14, K17,
integrin α6 and E-cadherin. Further analysis revealed characteristics of reduced scarring in NMR wounds including low collagen I to III ratio, increased HA
expression (HMW) and increased fibronectin expression. Transcriptional profiling
of TGFβ isoforms and different pro/anti-inflammatory cytokines revealed a balance
in the expression and repression of different cytokines, potentially contributing into
reduced scarring. Comparison of RNA-seq data from NMR and human fullthickness
wounds revealed a delay in the activation of important biological
processes and pathways in NMR skin in response to injury. Further analysis based on cultured human and NMR cells revealed differential regulation of TGFβ
signalling pathway between both species. 3-D collagen gel contraction assay
revealed that NMR fibroblast showed noticeable contraction but independently of
TGFβ treatment, while human fibroblast showed marked increased in gel
contraction in the presence of TGFβ. In conclusion, NMR can serve as a very useful
model to study human cutaneous wound healing. The reduced scarring in NMR
could be a result of multiple factors including HMW-HA, balanced cytokine
expression and differential regulation of different TGFβ cytokines as observed in
the in vitro studies.
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Cytosystematics, sex chromosome translocations and speciation in African mole-rats (Bathyergidae: Rodentia)Deuve, Jane Lynda 03 1900 (has links)
Thesis (PhD (Botany and Zoology))--University of Stellenbosch, 2008. / The Bathyergidae are subterranean rodents endemic to Africa south of the Sahara.
They are characterised by divergent diploid numbers that range from 2n=40 in
Fukomys mechowi to 2n=78 in F. damarensis. In spite of this variation there is
limited understanding of the events that shaped the extant karyotypes and in an
attempt to address this, and to shed light on the mode and tempo of chromosomal
evolution in the African mole-rats, a detailed analysis of both the autosomal and sex
chromosome components of the genome was undertaken. In addition to G- and Cbanding,
Heterocephalus glaber (2n=60) flow-sorted painting probes were used to
conduct cross-species chromosome painting among bathyergids. This allowed the
detection of a balanced sex chromosome-autosome translocation in F. mechowi that
involved a complex series of rearrangements requiring fractionation of four H. glaber
autosomes and the subsequent translocation of segments to sex chromosomes and to
the autosomal partners. The fixation of this rare rearrangement has probably been
favoured by the presence of an intercalary heterochromatic block (IHB) that was
detected at the boundary with the translocated autosomal segment. Male meiosis in
Cryptomys, the Fukomys sister clade, was investigated by immunostaining of the
SCP1 and SCP3 proteins involved in the formation of the synaptonemal complex.
This allowed confirmation of a Y-autosome translocation that is shared by C.
hottentotus subspecies. We discuss reduced recombination between Y and X2 that
seems to be heterochromatin dependent in the C hottentotus lineage, and the
implications this holds for the evolution of a meiotic sex chromosome chain such as
has been observed in platypus. By extending cross-species chromosome painting to
Bathyergus janetta, F. damarensis, F. darlingi and Heliophobius argenteocinereus,
homologous chromosomal regions across a total of 11 species/subspecies and an
outgroup were examined using cladistic and bioinformatics approaches. The results
show that Bathyergus, Georychus and Cryptomys are karyotypically highly conserved
in comparison to Heterocephalus, Heliophobius and Fukomys. Fukomys in particular
is characterised by a large number of rearrangements that contrast sharply with the
conservative Cryptomys. The occurrence and fixation of rearrangements in these
species has probably been facilitated by vicariance in combination with life history
traits that are particular to these mammals.
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The detection of thermal windows in fossorial rodents with varied sociality degreeVEJMĚLKA, František January 2018 (has links)
Eight rodent species with fossorial activity differing in a number of characteristics such as ecology, climatic conditions, geographical distribution, or kinship were studied using infrared thermography in order to describe their surface temperature and its patterns. An attempt to describe the relation between surface temperature and varied social organisation in burrowing rodents was made.
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Termoregulační schopnosti rypoše \kur{Fukomys darlingi} a jejich vývoj u mláďat / The Thermoregulatory Abilities in a Mole-rat \kur{Fukomys darlingi} and its Development in PupsZEMANOVÁ, Milada January 2010 (has links)
The oxygen consumption and body temperature were measured in adults and pups of a social Mashona mole-rat(Fukomys darlingi)to test poikilothermic traits in this species and effect of presence of adults on pup´s thermoregulation abilities. The adult´s resting metabolic rate was 0.76 {$\pm$} 0.20 mlO2g-1hod-1 in the thermoneutral zone 27-34°C. We did not confirm poikilotermic traits in this species, because body temperature was stable (33.0 {$\pm$} 0.5°C) at low ambient temperatures. The pups started to thermoregulate in age of one month and they are able to maintain stable body temperature very late in age of three months. My results indicate that presence of adults is necessary for thermoregulation of pups.
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Termoregulační schopnosti rypoše \kur{Fukomys darlingi} a jejich vývoj u mláďat / The Thermoregulatory Abilities in a Mole-rat \kur{Fukomys darlingi} and its Development in PupsZEMANOVÁ, Milada January 2010 (has links)
The oxygen consumption and body temperature were measured in adults and pups of a social Mashona mole-rat(Fukomys darlingi)to test poikilothermic traits in this species and effect of presence of adults on pup´s thermoregulation abilities. The adult´s resting metabolic rate was 0.76 {$\pm$} 0.20 mlO2g-1hod-1 in the thermoneutral zone 27-34°C. We did not confirm poikilotermic traits in this species, because body temperature was stable (33.0 {$\pm$} 0.5°C) at low ambient temperatures. The pups started to thermoregulate in age of one month and they are able to maintain stable body temperature very late in age of three months. My results indicate that presence of adults is necessary for thermoregulation of pups.
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The evolution of nuclear microsatellite DNA markers and their flanking regions using reciprocal comparisons within the African mole-rats (Rodentia: Bathyergidae)Ingram, Colleen Marie 30 October 2006 (has links)
Microsatellites are repetitive DNA characterized by tandem repeats of short
motifs (2 â 5 bp). High mutation rates make them ideal for population level studies.
Microsatellite allele genesis is generally attributed to strand slippage, and it is assumed
that alleles are caused only by changes in repeat number. Most analyses are limited to
alleles (electromorphs) scored by mobility only, and models of evolution rarely account
for homoplasy in allele length. Additionally, insertion/deletion events (indels) in the
flanking region or interruptions in the repeat can obfuscate the accuracy of genotyping.
Many investigators use microsatellites, designed for a focal species, to screen for
genetic variation in non-focal species. Comparative studies have shown different
mutation rates of microsatellites in different species, and even individuals. Recent
studies have used reciprocal comparisons to assess the level of polymorphism of
microsatellites between pairs of taxa.
In this study, I investigated the evolution of microsatellites within a phylogenetic
context, using comparisons within the rodent family Bathyergidae. Bathyergidae
represents a monophyletic group endemic to sub-Saharan Africa and relationships are well supported by morphological and molecular data. Using mitochondrial and nuclear
DNA, a robust phylogeny was generated for the Bathyergidae. From my results, I
proposed the new genus, Coetomys.
I designed species-specific genotyping and microsatellite flanking sequence
(MFS) primers for each genus. Sequencing of the MFS provided direct evidence of the
evolutionary dynamics of the repeat motifs and their flanking sequence, including
rampant electromorphic homoplasy, null alleles, and indels. This adds to the growing
body of evidence regarding problems with genotype scores from fragment analysis. A
number of the loci isolated were linked with repetitive elements (LTRs and SINEs),
characterized as robust phylogenetic characters. Results suggest that cryptic variation in
microsatellite loci are not trivial and should be assessed in all studies.
The phylogenetic utility of the nucleotide variation of the MFS was compared to
the well-resolved relationships of this family based on the 12S/TTR phylogeny.
Variation observed in MFS generated robust phylogenies, congruent with results from
12S/TTR. Finally, a number of the indels within the MFS provided a suite of suitable
phylogenetic characters.
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