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Christiane Denys - One of the best experts on this subject based on the ideXlab platform.
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systematics and diversification of Praomys species rodentia muridae endemic to the cameroon volcanic line west central africa
Zoologica Scripta, 2012Co-Authors: Alain Didier Missoup, Violaine Nicolas, Wim Wendelen, Ernest Keming, Charles Felix Bilong Bilong, Arnaud Couloux, Ekobo Atanga, Rainer Hutterer, Christiane DenysAbstract:Missoup, A.D., Nicolas, V., Wendelen, W., Keming, E., Bilong Bilong, C.F., Couloux, A., Atanga, E., Hutterer, R. & Denys, C. (2012). Systematics and diversification of Praomys species (Rodentia: Muridae) endemic to the Cameroon Volcanic Line (West Central Africa). —Zoologica Scripta, 41, 327–345. Our integrative approach combines two mitochondrial genes (16S and cyt b gene), two nuclear genes (exon 10 GHR and exon 1 IRBP) and craniometrical data to test the status and to infer phylogenetic relationships of the three Praomys Cameroon Volcanic Line endemics (P. hartwigi, P. morio and P. obscurus). The taxonomic rank of the principal genus group is assessed and the mode of diversification of species of the P. tullbergi complex in Afrotropical forests is discussed based on estimates of times to the most recent common ancestors and on tree topologies. This study documents for the first time the molecular and morphometrical distinctiveness of P. hartwigi and P. morio within the P. tullbergi species complex. Further studies including specimens of P. hartwigi from all its distribution range are needed to conclude on the status of P. obscurus. The monophyly of the genus Praomys is refuted. Times to the most recent common ancestors of major clades within the P. tullbergi species complex are estimated for the last 2.5 Mya and during the last 1 or 2 Mya for different species or forms. The lowland forest refuge hypothesis might well explain the diversification of P. misonnei, P. rostratus and P. tullbergi in the guineo-congolese forest block. The isolation of montane forests could have facilitated the divergence between the two montane forest forms P. hartwigi and P. obscurus and between populations of P. morio from the continent and those from the island of Bioko. Praomys populations (species) that inhabit the Cameroon Volcanic Line Praomys probably originated as lowland forms subsequently specialized to highland conditions.
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molecular and morphometric variation in two sibling species of the genus Praomys rodentia muridae implications for biogeography
Zoological Journal of the Linnean Society, 2010Co-Authors: Violaine Nicolas, Christiane Denys, Ayodeji Olayemi, Julian Kerbis C Peterhans, Wim Wendelen, Alain Didier Missoup, Bertin Akpatou, Jan Decher, Patrick Barriere, Corinne CruaudAbstract:The rodent genus Praomys is widely distributed in the African tropics. The species are cryptic, rendering the species taxonomy unclear. There are differences of opinion concerning the specific status of Praomys misonnei and Praomys tullbergi, and their geographical distribution. We sequenced the cytochrome b and/or the 16S gene of 221 specimens from 12 countries in order to evaluate the genetic variability within these two species, and to precisely determine their geographical distribution. Morphological and morphometrical analyses on the sequenced specimens were also performed to find criteria useful for the identification of museum specimens. Our results confirm that P. misonnei and P. tullbergi are two valid species that can be separated by molecular data. However, no single discrete morphological character or simple metric measurement can be used to discriminate them. The percentage of misclassified individuals in multivariate discriminant analysis is relatively high (10%). The two species have allopatric distributions: P. tullbergi occurs in West Africa, from eastern Guinea to western Ghana, and P. misonnei is widely distributed from eastern Ghana to western Kenya. Within P. misonnei we identified three or four major geographical clades: a West Central African clade, an East African clade, a Nigerian clade, and a possible West African clade. Within P. misonnei, high geographical morphometrical variability was also identified. The role of both rivers and Pleistocene forest refugia in promoting speciation within the genus Praomys is discussed.
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confrontation of morphological and molecular data the Praomys group rodentia murinae as a case of adaptive convergences and morphological stasis
Molecular Phylogenetics and Evolution, 2005Co-Authors: Emilie Lecompte, Christiane Denys, Laurent GranjonAbstract:Phylogenetic relationships in a group of 21 African rodent species designated as the Praomys group (Murinae) were investigated using morphological characters and sequence data from the complete mitochondrial cytochrome b gene and nuclear IRBP gene fragment (840bp). The molecular results confirm the monophyly of the Praomys group, including the species Malacomys verschureni, while the other Malacomys species appear very divergent. The basal relationships within the Praomys group are poorly resolved, suggesting a rapid radiation at about 7-9 million years ago based on genetic divergence rates calibrated from the fossil record. Discrepancies between molecular and morphological results probably reflect of numerous convergences as well as variations in the rates of morphological evolution among lineages. Reconstructions of the ancestral character states suggest a savannah origin for the Praomys group, along with some morphological traits conserved by stasis in savannah taxa. At the same time, forest taxa seem to be characterized by an accelerated morphological evolution, with acquisition of convergent adaptive characters.
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cytochrome b based phylogeny of the Praomys group rodentia murinae a new african radiation
Comptes Rendus Biologies, 2002Co-Authors: Emilie Lecompte, Laurent Granjon, Julian Kerbis C Peterhans, Christiane DenysAbstract:Complete cytochrome b gene sequences allows, for the first time, establishing a nearly complete phylogeny among the Praomys group sensu lato. The genera Praomys, Mastomys and Stenocephalemys appear paraphyletic. Myomys is polyphyletic and this genus name probably needs to be restricted to its type species, M. verreauxii. The genera Zelotomys and Colomys appear as sister groups. Mastomys pernanus and Malacomys verschureni nest within the Praomys group, but their generic assignation must be further clarified. The genus Heimyscus appears closest to Praomys than to Hylomyscus. The different lineages probably result from an adaptive radiation at the end of the Miocene.
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the phylogeny of the Praomys complex rodentia muridae and its phylogeographic implications
Journal of Zoological Systematics and Evolutionary Research, 2002Co-Authors: Emilie Lecompte, Christiane DenysAbstract:Among the African Murinae (Rodentia, Muridae), the Praomys complex, whose systematics has been studied by different approaches, has raised numerous taxonomic problems. Different taxa, namely Praomys, Mastomys, Myomys and Hylomyscus have been considered either as separate genera or subgenera of Praomys. In order to understand the relationships within the Praomys complex and to test the monophyly of the genus Praomys, a cladistic analysis was conducted, based on morpho-anatomical factors involving different species of Praomys, Mastomys, Myomys and Hylomyscus. The results indicate that the Praomys complex is monophyletic, as are the genera Hylomyscus, Mastomys and Myomys, whereas the genus Praomys appears paraphyletic. Indeed, a group of species including Praomys jacksoni was found to be more closely related to the genera Mastomys and Myomys than to a Praomys tullbergi-group. The biotopes and the distribution areas of the species were mapped on the phylogeny. It appears that the different clades each present a relative ecological cohesion and are arranged according to a gradient from closed to open habitats. From there, an evolutionary scenario is proposed for the emergence of the different clades and species of the genus Praomys sensu stricto.
Akio Matsuzawa - One of the best experts on this subject based on the ideXlab platform.
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Adrenocortical zonation in chamois-coloured mastomys, Praomys coucha.
Laboratory animals, 1995Co-Authors: Shin Tanaka, Manabu Nozaki, Akio MatsuzawaAbstract:Body and adrenal weights, and histology of the adrenal cortex were examined in the chamois-coloured mastomys (Praomys coucha) at inbred generations 3 to 10. Body and adrenal weights were consistently larger in males than in females, although the adrenal to body weight ratios tended to be lower before 50 days of age and were clearly higher after. Distinct sex differences were found in the adrenal cortex. The whole cortex and the zona reticularis were thicker in males and the zona reticularis became thicker in males, but thinner in females with age. The border zone characteristics of females of the wild-coloured mastomys strain, was not formed in the chamois-coloured strain. This was a very unique, interesting strain difference. Comparative studies of both strains may contribute to elucidation of the mechanism of border zone formation in the mastomys adrenal cortex.
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changes in major organ weights and ovarian histology with reproductive status in the inbred wild colored mastomys Praomys coucha mwc
Jikken dobutsu. Experimental animals, 1994Co-Authors: Shin Tanaka, Manabu Nozaki, Akio MatsuzawaAbstract:Effects of the reproductive activity upon major organ weights and ovarian histology were examined in the inbred wild-colored mastomys (Praomys coucha), MWC. The liver, ovary and spleen weights increased during pregnancy and kept the increased levels until weaning of the young in the former 2, but not in the last. The most characteristic histological changes were observed in the corpora lutea and interstitial cells. The corpora lutea changed in both size and number according to the reproductive status. The interstitium was meagre in virgins as observed in other laboratory rodents, but expanded during pregnancy. It contained two types of interstitial cells. One was characterized by light cytoplasm and the other by dark cytoplasm. The latter increased in number during pregnancy and occupied the interstitium exclusively. These changes suggested that the interstitial (steroidogenic) cells in the mastomys might have a unique and distinctive turnover mechanism as did those constituting the zona reticularis and border zone in the female mastomys adrenal cortex.
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effects of lactation on the border zone formation in the female mastomys Praomys coucha adrenal cortex
Cells Tissues Organs, 1991Co-Authors: S Tαnaka, Toshitake Fujioka, M Nozaki, Akio MatsuzawaAbstract:Adrenocortical zonation and especially border zone formation were investigated in relation to reproduction in female mastomys of the wild-colored inbred strain (MWC). The adrenal weight and the whole thickness of the cortex remained relatively constant throughout pregnancy, delivery and lactation. During pregnancy the zona fasciculata increased but the z. reticularis decreased in thickness. The border zone between the z. fasciculata and the z. reticularis thickened 2-fold during pregnancy and further 2-fold during lactation. This zone was composed of vacuolated cell layers and nodules in females with a normal reproductive career. In young virgins this zone was barely identified by the presence of a few highly vacuolated cells. These cells became prominent during pregnancy and lactation. During lactation two types of cell aggregations, distinguishable by their stain ability, vacuolation, localization and cellularity, appeared in the thickened border zone. The nodules first appeared within the z. reticularis after lactation. Neither thickening of both border zone and z. fasciculata nor formation of nodules occurred when lactation was interrupted after delivery. Thus, the changes in the female MWC adrenal, above all the appearance of nodules, seemed to be more dependent upon lactation than pregnancy. The vacuolated cells and the nodules might originate from the thickened z. fasciculata and the thinned z. reticularis respectively by the specific metamorphosis of the cells adjacent to the border zone. Their fusion and induction of fibrous tissue migration may result in the wider border zone.
Afework Bekele - One of the best experts on this subject based on the ideXlab platform.
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rodents of the menagesha state forest ethiopia with an emphasis on the endemic Praomys albipes ruppell 1842
Tropical Zoology, 1996Co-Authors: Afework BekeleAbstract:A shrew and 12 species of rodents were recorded from the Menagesha State Forest, Ethiopia, from November 1991 to July 1993. A total of 293 specimens were trapped in 3209 trap nights. Trap success varied from 4.7 to 26.9%. Praomys albipes Ruppell 1842 was the most ubiquitous, comprising 54.3% of the total rodents captured in all habitats and 70.8% of the rodents captured in the forest. Species number and richness was low in disturbed habitats. Composition and distribution of the rodent fauna were compared with studies in other localities of Ethiopia. The effect of habitat degradation on the distribution of species and its concern was stressed.
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population dynamics of the ethiopian endemic rodent Praomys albipes in the menagesha state forest
Journal of Zoology, 1996Co-Authors: Afework BekeleAbstract:Bimonthly live-trapping over 15 months of 1 ha grid in the Menagesha State Forest, Ethiopia, revealed six species of rodents, dominated by Praomys albipes (64.3% of the catch). All age groups were recorded at each trapping occasion, and pregnant females were observed throughout the year. Both snap-trapping and captive breeding programmes suggest a mean litter size greater than 4 (range 2–8). Despite this, the monthly density and biomass of captured rodents declined towards the last trapping occasions from 35 to 12/ha and 1546 to 454 g/ha, respectively.
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post natal development and reproduction in captive bred Praomys albipes mammalia rodentia from ethiopia
Mammalia, 1995Co-Authors: Afework BekeleAbstract:Un programme de reproduction en captivite a ete mis en oeuvre sur le rongeur endemique Ethiopien Praomys albipes. Des gestations ont ete enregistrees durant toute l'annee. L'importance de la portee a varie entre 2 et 6 nouveau-nes avec une moyenne de 4.1±1.3. Le poids moyen a la naissance s'etablit a 3 grammes. Des differences de poids furent observees parmi les portees de differentes tailles. La maturite sexuelle, la conception, les durees de gestation ainsi que le developpement des nouveau-nes sont decrits.
Violaine Nicolas - One of the best experts on this subject based on the ideXlab platform.
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Terrestrial small mammal diversity and abundance in Taï National Park, Côte d'Ivoire
Fund for Support and Development of Protected Areas, 2018Co-Authors: Bertin K. Akpatou, Blaise Kadjo, Kouakou H. Bohoussou, Violaine NicolasAbstract:A terrestrial small mammal species survey was carried out in the Taï National Park from March to June 2010, using Sherman's live traps and pitfall traps. The aim of the study was to determine the diversity and distribution of rodents and shrews in three different habitats: primary, secondary and swamp forests. During the study period, 263 terrestrial small mammals belonging to 17 species (six Soricidae species and eleven Muridae species) were captured out of 8,610 trap-nights. For Rodents, the most frequent species were Malacomys edwardsi (n = 76) followed by Hylomyscus simus (n = 53), Praomys rostratus (n = 51) and Hybomys planifrons (n = 27). For shrews, the most frequent species was Crocidura buettikoferi (n = 12) followed by Crocidura eburnea (n = 7). The species richness (S) and diversity index (H') were higher in the secondary forest (S = 15; H' = 2.12) than the ones of the primary forest (S = 10; H' = 1.79) and swamp forest (S = 8, H' = 1.74) respectively. In the primary forest, the population of terrestrial small mammals was dominated by four species: Malacomys edwardsi (n = 32), Praomys rostratus (n = 21), Hylomyscus simus (n = 15) and Hybomys planifrons (n = 13). In the secondary forest, Hylomyscus simus (n = 29), Malacomys edwardsi (n = 23) and Praomys rostratus (n = 18) were the most abundant. In swamp forest, the most abundant species were: Malacomys edwardsi (n = 21), Praomys rostratus (n = 12) and Hybomys planifrons (n = 11). Of the listed species, two species are worthy for conservation, C. buettikoferi (NT) and G. buntingi (DD), and ten were endemic to the Upper Guinea forests. These results confirm once again the important animal diversity of the Taï National Park, which harbours numerous species endemic to the Upper Guinea forests
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systematics and diversification of Praomys species rodentia muridae endemic to the cameroon volcanic line west central africa
Zoologica Scripta, 2012Co-Authors: Alain Didier Missoup, Violaine Nicolas, Wim Wendelen, Ernest Keming, Charles Felix Bilong Bilong, Arnaud Couloux, Ekobo Atanga, Rainer Hutterer, Christiane DenysAbstract:Missoup, A.D., Nicolas, V., Wendelen, W., Keming, E., Bilong Bilong, C.F., Couloux, A., Atanga, E., Hutterer, R. & Denys, C. (2012). Systematics and diversification of Praomys species (Rodentia: Muridae) endemic to the Cameroon Volcanic Line (West Central Africa). —Zoologica Scripta, 41, 327–345. Our integrative approach combines two mitochondrial genes (16S and cyt b gene), two nuclear genes (exon 10 GHR and exon 1 IRBP) and craniometrical data to test the status and to infer phylogenetic relationships of the three Praomys Cameroon Volcanic Line endemics (P. hartwigi, P. morio and P. obscurus). The taxonomic rank of the principal genus group is assessed and the mode of diversification of species of the P. tullbergi complex in Afrotropical forests is discussed based on estimates of times to the most recent common ancestors and on tree topologies. This study documents for the first time the molecular and morphometrical distinctiveness of P. hartwigi and P. morio within the P. tullbergi species complex. Further studies including specimens of P. hartwigi from all its distribution range are needed to conclude on the status of P. obscurus. The monophyly of the genus Praomys is refuted. Times to the most recent common ancestors of major clades within the P. tullbergi species complex are estimated for the last 2.5 Mya and during the last 1 or 2 Mya for different species or forms. The lowland forest refuge hypothesis might well explain the diversification of P. misonnei, P. rostratus and P. tullbergi in the guineo-congolese forest block. The isolation of montane forests could have facilitated the divergence between the two montane forest forms P. hartwigi and P. obscurus and between populations of P. morio from the continent and those from the island of Bioko. Praomys populations (species) that inhabit the Cameroon Volcanic Line Praomys probably originated as lowland forms subsequently specialized to highland conditions.
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the impact of the congo river and its tributaries on the rodent genus Praomys speciation origin or range expansion limit
Zoological Journal of the Linnean Society, 2011Co-Authors: Jan Kennis, Violaine Nicolas, J Hulselmans, Pionus Katuala, Wim Wendelen, Erik Verheyen, Akaibe Dudu, Herwig LeirsAbstract:We studied the taxonomy, distribution, and ecology of species within Praomys, a common rodent genus present in rainforests and montane forests in sub-Saharan Africa. The taxonomy of the group is problematic, and for the sampled region of Kisangani (Democratic Republic of Congo) no prior genetic study has been published. We used a combination of molecular (cyt b sequencing) and craniometric techniques (canonical analyses of skull measurements) for the species identification of a total of 654 specimens. We confirm the presence of Praomys minor in the region, up to now only known from the type and paratype specimens. At least seven species are present in the Kisangani region, and two clades occur along both banks of the Congo River. The present-day distribution of the genus seems to be influenced by large-scale rainforest fragmentation related to drier periods in geological history. The Congo River could in this case constitute a modern barrier to gene flow when the climate enabled rainforest expansion. The tributaries of the Congo River play no role in limiting Praomys species distribution, apart from the Aruwimi River for Praomys jacksoni s.l. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163, 983–1002.
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molecular and morphometric variation in two sibling species of the genus Praomys rodentia muridae implications for biogeography
Zoological Journal of the Linnean Society, 2010Co-Authors: Violaine Nicolas, Christiane Denys, Ayodeji Olayemi, Julian Kerbis C Peterhans, Wim Wendelen, Alain Didier Missoup, Bertin Akpatou, Jan Decher, Patrick Barriere, Corinne CruaudAbstract:The rodent genus Praomys is widely distributed in the African tropics. The species are cryptic, rendering the species taxonomy unclear. There are differences of opinion concerning the specific status of Praomys misonnei and Praomys tullbergi, and their geographical distribution. We sequenced the cytochrome b and/or the 16S gene of 221 specimens from 12 countries in order to evaluate the genetic variability within these two species, and to precisely determine their geographical distribution. Morphological and morphometrical analyses on the sequenced specimens were also performed to find criteria useful for the identification of museum specimens. Our results confirm that P. misonnei and P. tullbergi are two valid species that can be separated by molecular data. However, no single discrete morphological character or simple metric measurement can be used to discriminate them. The percentage of misclassified individuals in multivariate discriminant analysis is relatively high (10%). The two species have allopatric distributions: P. tullbergi occurs in West Africa, from eastern Guinea to western Ghana, and P. misonnei is widely distributed from eastern Ghana to western Kenya. Within P. misonnei we identified three or four major geographical clades: a West Central African clade, an East African clade, a Nigerian clade, and a possible West African clade. Within P. misonnei, high geographical morphometrical variability was also identified. The role of both rivers and Pleistocene forest refugia in promoting speciation within the genus Praomys is discussed.
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the presence of Praomys lophuromys and deomys species muridae mammalia in the forest blocks separated by the congo river and its tributaries kisangani region democratic republic of congo
Mammalia, 2008Co-Authors: Pionus Katuala, Jan Kennis, Violaine Nicolas, J Hulselmans, Wim Wendelen, Erik Verheyen, Akaibe Dudu, Natalie Van Houtte, Theo Dierckx, Herwig LeirsAbstract:Praomys (four species), Lophuromys (four) and Deomys (one) are among the most common Muridae in the Kisangani region. To establish whether or not rivers constitute dispersal barriers for these rodents, we investigated the presence of these genera and their species in eight localities that are either separated by the Congo River or its tributaries. A total of 42,466 trapping nights resulted in the collection of 1185 Praomys, 233 Lophuromys and 209 Deomys ferrugineus. We observed that in almost all cases the studied species appear to have restricted distribution ranges, and that it is likely that the importance of the rivers as a barrier differs for the studied species. For example, P. misonnei was only collected from the right bank of the Congo, while P. lukolelae appears to be restricted to the left bank. In contrast, Praomys identified as P. mutoni or as members of the P. jacksoni species complex are collected on both sides of the Congo River. In contrast, all Lophuromys species were collected in a limited number of sampling sites only. L. dudui and L. luteogaster were only collected along the right bank of the Congo River, and the latter species appears to be restricted to the right bank of the Lindi River. L. huttereri and L. rita are only detected on the left bank of the Congo River. However, additional sampling is required to confirm that D. ferrugineus and L. luteogaster (so far both species have only been recorded on the right bank) do not occur in Bomane on the right bank of the Aruwimi (Ituri) River. In agreement with earlier findings for larger mammals, and pending additional taxonomical work on the P. jacksoni species complex, our findings confirm that the Congo River constitutes a barrier that limits the dispersal of all studied murids, except P. mutoni
Shin Tanaka - One of the best experts on this subject based on the ideXlab platform.
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genetic regulation of border zone formation in female mastomys Praomys coucha adrenal cortex
Journal of Heredity, 1996Co-Authors: Shin Tanaka, M Nozakiukai, J Kitoh, A MatsuzawaAbstract:The unique border zone between the zona fasciculata and z. reticularis of the female adrenal cortex is formed in the wild-colored inbred mastomys (Praomys coucha) strain, MWC, but never in the chamois-colored inbred strain, MCC. This clear strain-specific trait was genetically analyzed using F1, F2, and backcross progenies produced between MWC and MCC. Reciprocal crosses gave no significant differences in the phenotypic ratio of F1 or F2 progeny. Border zone formation was detected in 0% of F1 females, 25.8% of F2 females, 0% of backcross females between F1 and MCC, and 47.7% of backcross females between F1 and MWC. From these results, it was concluded that border zone formation in the female MWC adrenal is regulated by a single autosomal recessive gene and this gene was named bzf (border zone formation).
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Adrenocortical zonation in chamois-coloured mastomys, Praomys coucha.
Laboratory animals, 1995Co-Authors: Shin Tanaka, Manabu Nozaki, Akio MatsuzawaAbstract:Body and adrenal weights, and histology of the adrenal cortex were examined in the chamois-coloured mastomys (Praomys coucha) at inbred generations 3 to 10. Body and adrenal weights were consistently larger in males than in females, although the adrenal to body weight ratios tended to be lower before 50 days of age and were clearly higher after. Distinct sex differences were found in the adrenal cortex. The whole cortex and the zona reticularis were thicker in males and the zona reticularis became thicker in males, but thinner in females with age. The border zone characteristics of females of the wild-coloured mastomys strain, was not formed in the chamois-coloured strain. This was a very unique, interesting strain difference. Comparative studies of both strains may contribute to elucidation of the mechanism of border zone formation in the mastomys adrenal cortex.
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changes in major organ weights and ovarian histology with reproductive status in the inbred wild colored mastomys Praomys coucha mwc
Jikken dobutsu. Experimental animals, 1994Co-Authors: Shin Tanaka, Manabu Nozaki, Akio MatsuzawaAbstract:Effects of the reproductive activity upon major organ weights and ovarian histology were examined in the inbred wild-colored mastomys (Praomys coucha), MWC. The liver, ovary and spleen weights increased during pregnancy and kept the increased levels until weaning of the young in the former 2, but not in the last. The most characteristic histological changes were observed in the corpora lutea and interstitial cells. The corpora lutea changed in both size and number according to the reproductive status. The interstitium was meagre in virgins as observed in other laboratory rodents, but expanded during pregnancy. It contained two types of interstitial cells. One was characterized by light cytoplasm and the other by dark cytoplasm. The latter increased in number during pregnancy and occupied the interstitium exclusively. These changes suggested that the interstitial (steroidogenic) cells in the mastomys might have a unique and distinctive turnover mechanism as did those constituting the zona reticularis and border zone in the female mastomys adrenal cortex.
