117,703 research outputs found
Reassessment of the largest Pleistocene rhinocerotine Rhinoceros platyrhinus (Mammalia, Rhinocerotidae) from the Upper Siwaliks (Siwalik Hills, India)
No full textWe describe and figure a well-preserved, large skull of a rhinoceros, NHMUK 36661, collected in 1860 from Upper Siwalik deposits. This specimen can be referred to Rhinoceros platyrhinus. Comparison with the type material of R. platyrhinus revealed that several specimens previously referred to this taxon, including the lectotype, should instead be assigned to Rhinoceros sp. (potentially R. sivalensis or R. unicornis). Therefore, we here provide new detailed cranial and dental characters for R. platyrhinus, which is currently known only by a few specimens collected from a restricted area of northern India. We suggest that the generic name Punjabitherium erected for R. platyrhinus represents a junior synonym of Rhinoceros due to the morphological affinities of NHMUK 36661 with R. unicornis. A principal component analysis and a cluster analysis confirmed the morphological similarities between R. platyrhinus and R. unicornis. Rhinoceros platyrhinus represents the largest rhinocerotine species in Eurasia and is characterized by a long skull and high-crowned teeth, suggesting that it was a grazer rather than a mixed feeder such as R. unicornis. This is supported by a cluster analysis on the upper teeth. The progressive increase in aridity from ca. 12 Ma to Recent in northern India could have affected the dietary regime of R. platyrhinus towards to a more grazer-like diet
Phospholipid hydroperoxide glutathione peroxidase in bull spermatozoa provides a unique marker in the quest for semen quality analysis
No full textPhospholipid hydroperoxide glutathione peroxidase (PHGPx) is a selenoperoxidase accounting for most of the selenium content in mammalian testis, which has been found to be linked to fertility in humans. In this study, we addressed the issue whether PHGPx content in spermatozoa could be a predictive index of fertilization capacity for sire selection in bulls. Measurement of PHGPx in spermatozoa of 92 yearling bulls of three different Italian breeds (Chianina, Romagnola, and Marchigiana) revealed the presence of two quite well separated populations. A PHGPx activity of 130 mU/mg separated the high-PHGPx group (H-PHGPx, n = 73) from the low-PHGPx group (L-PHGPx, n = 19). Forward motility was markedly higher in the H-PHGPx group, which also contained a lower percentage of detached heads, abnormal midpiece, and proximal droplets. On the other hand, differently from the human studies, no correlation was observed between PHGPx activity and number of spermatozoa in the ejaculate. Apart from sperm count, which typically differed among breeds, and number of detached heads in the L-PHGPx group, which correlated with higher sperm Count, no other significant difference in seminal parameters among breeds was apparent. The assay for sperm PHGPx activity therefore emerges as a unique tool to evaluate semen quality for sire selection. (C) 2009 Elsevier Inc. All rights reserved
Did the Late Pleistocene climatic changes influence evolutionary trends in body size of the red deer? The study case of the Italian Peninsula
No full textVariations in the body size of red deer (Cervus elaphus) have been reported by several authors from several European fossiliferous localities for the Late Pleistocene and Holocene. Recently, several contributions focused on body size variation of red deer populations from the Italian Peninsula. Evolutionary trends of phenotypic traits may follow distinct tempos and modes of evolution such as Brownian, Ornstein-Uhlenbeck, stasis or random walk. Here, we investigated which evolutionary model better explained the temporal trend in body size of C. elaphus ssp. from the Italian Peninsula using modern statistical tools. We also tested the potential relationships between climate change and geographical variation through the Late Pleistocene. Our sample includes 1090 specimens from several peninsular Italian localities. For each specimen, we extracted the Size Variation Index calculated on postcranial elements. We found that stasis was the model better explaining the body size evolution in C. elaphus. We also found a nonsignificant interaction between body size and climate, whereas we detected a significant relationship with geography. We hypothesized that the red deer phenotypical plasticity was able to mitigate the selective constraints driven by climatic changes and geographical variability through the Late Pleistocene and Holocene, therefore returning a no neat variation in body size
Functional interaction of phospholid hydroperoxide glutathione peroxidase with sperm mitochondrion-associated cysteine-rich protein discloses the adjacent cysteine motif as a new substrate of the Se-peroxidase.
No full textThe mitochondrial capsule is a selenium- and disulfide-rich structure enchasing the outer mitochondrial membrane of mammalian spermatozoa. Among the proteins solubilized from the sperm mitochondrial capsule, we confirmed, by using a proteomic approach, the presence of phospholipid hydroperoxide glutathione peroxidase (PHGPx) as a major component, and we also identified the sperm mitochondrion-associated cysteine-rich protein ( SMCP) and fragments/aggregates of specific keratins that previously escaped detection (Ursini, F., Heim, S., Kiess, M., Maiorino, M., Roveri, A., Wissing, J., and Flohe ', L. ( 1999) Science 285, 1393 - 1396). The evidence for a functional association between PHGPx, SMCP, and keratins is further supported by the identification of a sequence motif of regularly spaced Cys-Cys doublets common to SMCP and high sulfur keratin-associated proteins, involved in bundling hair shaft keratin by disulfide cross-linking. Following the oxidative polymerization of mitochondrial capsule proteins, catalyzed by PHGPx, two-dimensional redox electrophoresis analysis showed homo- and heteropolymers of SMCP and PHGPx, together with other minor components. Adjacent cysteine residues in SMCP peptides are oxidized to cystine by PHGPx. This unusual disulfide is known to drive, by reshuffling oxidative protein folding. On this basis we propose that oxidative polymerization of the mitochondrial capsule is primed by the formation of cystine on SMCP, followed by reshuffling. Occurrence of reshuffling is further supported by the calculated thermodynamic gain of the process. This study suggests a new mechanism where selenium catalysis drives the cross-linking of structural elements of the cytoskeleton via the oxidation of a keratin-associated protein
Variations in the cranial morphology in European and North American rhinocerotidae from Eocene to Miocene: preliminary report
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Evolutionary trends and stasis in carnassial teeth of European Pleistocene wolf Canis lupus (Mammalia, Canidae)
No full textThe evolutionary trends of tooth size in quaternary carnivores support an almost direct association with climate. However, phenotypic trait may follow distinct tempo and mode of evolution such as Brownian, Ornstein-Uhlenbeck or random walk. Here, we investigated the morphometric variations and evolutionary trends in the carnassial teeth size of the European wolf (Canis lupus) by means of modern statistical tools. Recent contributions highlighted linear increase trend in tooth size through the Pleistocene, but those differences in time have not been tested using modern statistical strategies. Examining a wide sample of linear measurements of carnassials of extinct and extant wolves (486 M1 and 491 P4), we tested which evolutionary model (random walk, stasis, Ornstein-Uhlenbeck) better explains the dimensional pattern of teeth through time at the continental scale and at the regional scale (France and Italy). Our results clearly show different models for the carnassials of C. lupus. Lower and upper carnassials for the entire sample of C. lupus are characterized by a directional trend, whereas Italian and French subsets show a random fluctuation of carnassials size through time. The carnassials dimensions are not directly correlated with the climate changes during the Middle-Late Pleistocene and Holocene, but they are possibly correlated with spread of the cold mega-fauna in Europe, and thus with the changes in the dietary regime
Ricongiungimenti familiari di immigrati in Provincia di Milano – Indagine conoscitiva: l’esperienza del Servizio Minori e Famiglia della Provincia di Milano
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(2006) - Eocene Neochelys (Podocnemidae, Pleurodira, Testudinata) of Italy and their palaeobiogeography
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