A method for studying histochemical reactions in intact human dentine with a polarizing incident light microscope

Localization and distribution of non-specific esterases has been studied in intact human dentine, by reflected light microscopy. The method of specimen preparation described here permits the visualization of optical sections in depth within the specimen at high optical resolution. Non-specific esterase was found deposited as discrete bands across the tubules. or as droplets, or as a diffuse microsomal variety in the dentinal tubules and in the interglobular spaces. It was possible to distinguish the droplet variety from the microsomal variety, of esterase within the same tubule, by means of a novel optical method using antiflex and differential interference contrast systems of reflected light microscopy. It was found that the coefficient of reflection of dentine diminished gradually from the enamel to the pre-dentine and was inversely related to the scattering of light in dentine. This scattering plays an important role in the formation of the image with reflected light microscopy. The reflected light microscope offers an economically attractive alternative or a supplementary mode of microscopy to the confocal scanning microscopes for studying intact dentine at varying depths.     

The presence of open dentinal tubules affects the biological properties of dental pulp cells <Emphasis Type="Italic">Ex Vivo</Emphasis>

To investigate the effects of open dentinal tubules on the morphological and functional characteristics of dental pulp cells. Morphological changes in human dental pulp cells that were seeded onto dentin discs with open dentinal tubules were investigated on days 1, 2, 4, and 10 of culture using scanning electron microscopy and fluorescence microscopy. Samples collected on days 1, 3, 6, 8, and 10 of culture were evaluated for cell proliferation rate and alkaline phosphatase activity. Cultured human dental pulp cells developed a columnar or polygonal morphology and monopolar cytoplasmic processes that extended into the dentinal tubules. The cells formed a multilayer and secreted an extracellular matrix onto the cell surface. Scanning electron microscopy and fluorescence microscopy revealed polarized organization of odontoblasts. Cells seeded onto dentin discs proliferated minimally but showed high levels of ALP activity. Dental pulp cells seeded onto treated dentin discs develop an odontoblastlike phenotype, which may be a potential alternative for use in experimental research on dentinogenesis.     

Gaps, parsimony, and early Miocene elephantoids (Mammalia), with a re-evaluation of Gomphotherium annectens (Matsumoto, 1925)

A new analysis of the morphology of the cranium of the early Miocene species Gomphotherium annectens (Matsumoto, 1925) alters significantly previous hypotheses on the differentiation of Miocene Elephantoidea. The gomphotheres, excluding shovel-tusked mastodonts and choerolophodonts, are known to be a paraphyletic grouping: a stem group for elephantids+stegodontids. From parsimony analyses it seems very likely that early Miocene Old World so-called gomphotheres (Gomphotherium 'annectens group') are not closely related to other gomphotheres.     

Origins of bone repair in the armour of fossil fish: response to a deep wound by cells depositing dentine instead of dermal bone

The outer armour of fossil jawless fishes (Heterostraci) is, predominantly, a bone with a superficial ornament of dentine tubercles surrounded by pores leading to flask-shaped crypts (ampullae). However, despite the extensive bone present in these early dermal skeletons, damage was repaired almost exclusively with dentine. Consolidation of bone, by dentine invading and filling the vascular spaces, was previously recognized in Psammolepis and other heterostracans but was associated with ageing and dermal shield wear (reparative). Here, we describe wound repair by deposition of dentine directly onto a bony scaffold of fragmented bone. An extensive wound response occurred from massive deposition of dentine (reactionary), traced from tubercle pulp cavities and surrounding ampullae. These structures may provide the cells to make reparative and reactionary dentine, as in mammalian teeth today in response to stimuli (functional wear or damage). We suggest in Psammolepis, repair involved mobilization of these cells in response to a local stimulatory mechanism, for example, predator damage. By comparison, almost no new bone is detected in repair of the Psammolepis shield. Dentine infilling bone vascular tissue spaces of both abraded dentine and wounded bone suggests that recruitment of this process has been evolutionarily conserved over 380 Myr and precedes osteogenic skeletal repair.     

三星堆象牙埋藏环境可培养厌氧微生物分离及多样性分析

【背景】埋藏环境与文物劣化有着密切的关系,微生物被认为是导致文物劣化和消失的重要原因之一。埋藏环境下的三星堆象牙处于深埋、缺氧的条件,但目前对该环境下的厌氧菌缺乏必要的了解。【目的】以三星堆象牙埋藏层土壤为研究对象,探究埋藏环境可培养厌氧微生物多样性和影响微生物分布的因素,为深入研究厌氧微生物产酸、产蛋白酶等功能及象牙劣化机理提供菌株资源和理论参考。【方法】利用厌氧工作站,采用3种厌氧菌分离培养基分离三星堆象牙埋藏层土壤中的厌氧微生物,分析不同培养基对厌氧菌的分离效果,对分离菌株进行16S rRNA基因系统发育分析,揭示三星堆不同象牙埋藏环境中可培养厌氧微生物的多样性,并采用Mantel检验研究影响三星堆象牙埋藏环境可培养厌氧微生物分布的环境因子。【结果】从三星堆象牙埋藏层土壤中共分离获得61株厌氧菌,16S rRNA基因测序分析结果显示分离菌株均属于发酵厌氧微生物,分属于梭菌科(Clostridiaceae)与消化链球菌科(Peptostreptococcaceae)共2个科,梭菌属(Clostridium)、土生孢杆菌属(Terrisporobacter)、哈撒韦氏菌属(Hathewaya)、Haloimpatien共4个属,Clostridium cibarium、拜氏梭菌(Clostridium beijerinckii)、大梭菌(Clostridium magnum)、硝醛酚梭菌(Clostridium nitrophenolicum)、Clostridium kogasense、肠梭菌(Clostridium intestinale)、生孢梭菌(Clostridium sporogenes)、Clostridium sp. (A4d)、马永贝土生孢杆菌(Terrisporobacter mayombei)、Hathewaya massiliensis、Haloimpatiens massiliensis共11个种;所采用的3种分离培养基中,强化梭菌培养基分离获得的发酵厌氧菌数量和种类最多,但其他2种培养基也表现出独特的分离效果;Mantel检验结果表明,可培养发酵厌氧菌种群分布特征与Cu、Pb的含量呈显著正相关。【结论】三星堆象牙埋藏环境可培养发酵厌氧微生物的分布存在一定差异,K8象牙埋藏层土壤中可培养发酵厌氧菌丰富度与多样性均最高,多种培养基综合利用有利于分离出更为丰富多样的微生物类群,Cu、Pb与有机质含量是影响三星堆象牙埋藏层土壤可培养发酵厌氧菌种群分布的关键因素。     

The anatomy of Odobenocetops (Delphinoidea, Mammalia), the walrus-like dolphin from the Pliocene of Peru and its palaeobiological implications

The Pliocene Beds of the Pisco Formation on the southern coast of Peru have yielded three new skulls of the walrus-like odontocete, Odobenocetops (Delphinoidea, Cetacea). Two of the skulls are from a slightly younger horizon than the holotype of O. peruvianus and belong to a different species, O. leptodon . The holotype of O. leptodon bears a 135 cm long needle-like right tusk and a small 25 cm long left tusk, the apex of which was erupted. The third skull, referred to a female of O. peruvianus , bears two small tusks similar in size to the small left tusk of the holotype. The new specimens include periotic, tympanic and ear ossicles, which confirm referral to the Order Cetacea and the morphology of the humerus reinforces affinities of odobenocetopsids to monodontids. Because the anterodorsal edge of its orbit is slightly concave O. leptodon had reduced anterodorsal binocular vision, a condition compensated for by the probable presence of a small melon (and inferred echolocation). The head was bent ventrally when swimming in such a way that the long tusk was approximately parallel to the axis of the body. The extremely salient occipital condyles of Odobenocetops are indicative of great mobility of the neck, probably related to bottom-feeding. © 2002 The Linnean Society of London, Zoological Journal of the Linnean Society , 2002, 134 , 423–452.     

Découverte de Zygolophodon turicensis(Schinz) (Proboscidea,Mammalia) au lieu-dit Malartic a Simorre,Gers (Vindobonien moyen); Implications paléoécologiques et biostratigraphiques

The Vindobonian locality of Malartic (Gers),yielded a mammalian fauna characterized by the association of Brachypotherium brachypus and Zygolophodon turicensis. One can demonstrate the controversial existence of Z. turicensis in the french Miocene from a near complete dentition belonging to one specimen. This species can be clearly distinguished from the bunodont mastodont Gomphotherium angustidens from numerous characters of the tusks and molars. Z. turicensis immigrated in France in the middle Burdigalian (zone of Artenay in the Orléanais Sands), together with G. angustidens and Eotragus artenensis. This immigration puts a further point to establish the major event in continental stratigraphy of the middle Burdigalian mammalian immigration. Z. turicensis seems to be a forest animal and G. angustidens an inhabitant of savannah.     

Changes in the Ruaha elephant population caused by poaching

Found-ivory records complement the information provided by aerial surveys to illustrate changes in the Ruaha elephant population between 1973 and 1988. Intense poaching in the late 1970s and early 1980s reduced the numbers of elephants by about 60% and also distorted the age structure of the survivors. There are now few cows > 34 years and few bulls > 16 years. Footprint measurements in 1989 showed a lack of calves aged 2 to 9 years but many new-born infants.     

我国非法象牙贸易犯罪侦防对策研究

非法象牙贸易犯罪在我国野生动物犯罪中占比较重。由于非法象牙贸易具有利润高、查处难,以及国人对象牙制品的偏好,在我国颁布象牙商业性禁贸政策后,国内相关犯罪形势依旧严峻。越来越多的非法象牙贸易犯罪利用互联网的隐蔽性、匿名性进行线上沟通,随后通过寄递业务进行线下交易。为维护物种多样性及生态可持续发展,需通过加大对寄递行业的监管力度、加强刑侦基础工作建设、深化大数据的侦查应用、培养个人与企业自律意识、健全协作机制等途径进行非法象牙贸易犯罪的打击与防范。     

Contribution of isotopic biogeochemistry (13C, 15N, 18O) to the paleoecology of mammoths (mammuthus primigenius)

Carbon isotopic abundances in Alaskan, Albertan and Russian mammoths indicate a diet of C₃‐plants. The relatively high nitrogen isotopic abundances suggest arid conditions in Alberta and Alaska during the last ice age, and similar conditions in Russia. Nitrogen isotopic abundances are higher in mammoths relative to coeval herbivores, which may be due to differences in protein content of their diet. Oxygen isotopic abundances are similar in mammoths and in modern mammals from the same areas. The characteristic isotopic signature of mammoth ivory allows distinction from elephant or marine mammal ivory.