中国广西晚白垩世一新的巨龙类恐龙

记述了采自广西南宁市郊晚白垩世地层中一巨龙类恐龙新属种:右江清秀龙(Qingxiu- saurus youjiangensis gen.et sp.nov.)。新属种正型标本包括以下不关联的头后骨骼:一段较完整的前部尾椎神经棘、左右胸骨板、左右肱骨。它以以下独特特征组合区别于其他巨龙类:前部尾椎神经棘板状结构不发育、相对较高并呈桨状;胸骨与肱骨最大长之比值较低(约0.65)。广西发现的新属种以及近年来报道的巨龙类恐龙材料表明,亚洲巨龙类恐龙的头后骨骼形态变异度高,白垩纪时期这类恐龙曾在亚洲广为分布。     

Sauropod diversity in the Late Cretaceous of southwestern Europe: The lessons of odontology

Recent discoveries in southern France and northern Spain suggest that the morphology of titanosaurian teeth shows much greater variations that previously thought. It is suggested that the different morphotypes are informative at specific or generic level and that titanosaurian genera may indeed be recognized by their isolated teeth. It is also confirmed that juvenile titanosaurian teeth have a rather uniform, cylindrical morphology. Four different morphotypes are described for the Ibero-Armorican Island in the Late Cretaceous.     

A New Titanosaurian Braincase from the Cretaceous “Lo Hueco” Locality in Spain Sheds Light on Neuroanatomical Evolution within Titanosauria

Despite continuous improvements, our knowledge of the neurocranial anatomy of sauropod dinosaurs as a whole is still poor, which is especially true for titanosaurians even though their postcranial remains are common in many Upper Cretaceous sites worldwide. Here we describe a braincase from the uppermost Cretaceous locality of ‘‘Lo Hueco” in Spain that is one of the most complete titanosaurian braincases found so far in Europe. Although the titanosaurian Ampelosaurus sp. is known from the same locality, this specimen is clearly a distinct taxon and presents a number of occipital characters found in Antarctosaurus and Jainosaurus, which are approximately coeval taxa from southern Gondwana. The specimen was subjected to X-ray computed tomographic (CT) scanning, allowing the generation of 3D renderings of the endocranial cavity enclosing the brain, cranial nerves, and blood vessels, as well as the labyrinth of the inner ear. These findings add considerable knowledge to the field of sauropod paleoneuroanatomy in general and titanosaurian endocast diversity in particular. Compared with that of many sauropodomorphs, the endocast appears only slightly flexed in lateral view and bears similarities (e.g., reduction of the rostral dural expansion) with Gondwanan titanosaurians such as Jainosaurus, Bonatitan, and Antarctosaurus. The vestibular system of the inner ear is somewhat contracted (i.e., the radius of the semicircular canals is small), but less so than expected in derived titanosaurians. However, as far as the new specimen and Jainosaurus can be contrasted, and with the necessary caution due to the small sample of comparative data currently available, the two taxa appear more similar to one another in endocast morphology than to other titanosaurians. Recent phylogenetic analyses of titanosaurians have not included virtually any of the taxa under consideration here, and thus the phylogenetic position of the new Spanish titanosaurian—even its generic, let alone specific, identification—is not possible at the moment. Nevertheless, both the braincase osteology and the endocast morphology suggest that the specimen represents a derived titanosaurian that presumably branched further from the base of Lithostrotia, potentially even near Saltasauridae, comparable in evolutionary terms with Jainosaurus.     

Dinosaur speed demon: the caudal musculature of Carnotaurus sastrei and implications for the evolution of South American abelisaurids

In the South American abelisaurids Carnotaurus sastrei, Aucasaurus garridoi, and, to a lesser extent Skorpiovenator bustingorryi, the anterior caudal ribs project at a high dorsolateral inclination and have interlocking lateral tips. This unique morphology facilitated the expansion of the caudal hypaxial musculature at the expense of the epaxial musculature. Distinct ridges on the ventrolateral surfaces of the caudal ribs of Aucasaurus garridoi are interpreted as attachment scars from the intra caudofemoralis/ilio-ischiocaudalis septa, and confirm that the M. caudofemoralis of advanced South American abelisaurids originated from a portion of the caudal ribs. Digital muscle models indicate that, relative to its overall body size, Carnotaurus sastrei had a substantially larger M. caudofemoralis than any other theropod yet studied. In most non-avian theropods, as in many extant sauropsids, the M. caudofemoralis served as the primary femoral retractor muscle during the locomotive power stroke. This large investment in the M. caudofemoralis suggests that Carnotaurus sastrei had the potential for great cursorial abilities, particularly short-burst sprinting. However, the tightly interlocking morphology of the anterior caudal vertebrae implies a reduced ability to make tight turns. Examination of these vertebral traits in evolutionary context reveals a progressive sequence of increasing caudofemoral mass and tail rigidity among the Abelisauridae of South America.     

A complete skull of an early cretaceous sauropod and the evolution of advanced titanosaurians

Advanced titanosaurian sauropods, such as nemegtosaurids and saltasaurids, were diverse and one of the most important groups of herbivores in the terrestrial biotas of the Late Cretaceous. However, little is known about their rise and diversification prior to the Late Cretaceous. Furthermore, the evolution of their highly-modified skull anatomy has been largely hindered by the scarcity of well-preserved cranial remains. A new sauropod dinosaur from the Early Cretaceous of Brazil represents the earliest advanced titanosaurian known to date, demonstrating that the initial diversification of advanced titanosaurians was well under way at least 30 million years before their known radiation in the latest Cretaceous. The new taxon also preserves the most complete skull among titanosaurians, further revealing that their low and elongated diplodocid-like skull morphology appeared much earlier than previously thought.     

Patterns of caudal-autotomy evolution in lizards

Using comparative techniques to account for phylogenetic effects, I examined patterns of evolution of caudal autotomy and foraging in 39 lizard species to test the hypothesis that caudal autotomy has co-evolved with morphology, locomotor performance, and foraging behaviour. There were significant positive associations between evolution of the point on the tail (distance from cloaca) at which tail loss occurs (an indirect measure of caudal autotomy) and evolution of each of the following: tail length, caudifemoralis longus (CFL) muscle length, and jump distance. The correlation with the evolution of sprint speed approached significance. These relationships primarily were due to the influence of tail-length evolution on autotomy-point evolution. With the effect of tail-length evolution removed, autotomy-point evolution was negatively correlated with the evolution of tail-loss frequency. The CFL restricts tail loss to portions of the tail posterior to the most distal point of its insertion in the tail. In addition, with the effect of tail-length evolution removed, CFL length co-evolved with sprint speed. These results indicate that tail morphology has co-evolved with caudal autotomy such that the evolution of the CFL has reduced caudal autotomy in certain groups of lizards.
Ambush foraging, the ability to lose the tail, intermediate CFL length, and low locomotor performance (i.e. slow sprint speed and short jump distance) are hypothesized to be the ancestral conditions in lizards using outgroup rooting. The diversification of lizard taxa has resulted in some lineages moving away from ancestral character states (i.e. family Teiidae, superfamily Varanoidea), while others are very similar or identical to their ancestors (i.e. superfamily Iguania).     

Studies of the Influence of Diet on Clearing-Factor Lipase (CFL) and Blood Lipid Levels of a Patient with Hyperlipidemia

A 30-year-old man was studied who had hyperlipidemia of a hereditary nature which was at first thought to be refractory to changes in diet. It was subsequently shown that the lipemia was adequately controlled by diet. The patient had no defect in his ability to produce clearing-factor lipase (CFL) following heparin injection, his chylomicra were not refractory to CFL, and his plasma showed no more than ordinary inhibitory activity against CFL. Under dietary conditions which resulted in a high degree of lipemia, much of the CFL was rendered inactive by adsorption on the chylomicra. The results suggest that the role of CFL in patients with hyperlipidemia may be minor.     

Phylogeny and taxonomy of the round-eared sengis or elephant-shrews, genus Macroscelides (Mammalia, Afrotheria, Macroscelidea)

The round-eared sengis or elephant-shrews (genus Macroscelides) exhibit striking pelage variation throughout their ranges. Over ten taxonomic names have been proposed to describe this variation, but currently only two taxa are recognized (M. proboscideus proboscideus and M. p. flavicaudatus). Here, we review the taxonomic history of Macroscelides, and we use data on the geographic distribution, morphology, and mitochondrial DNA sequence to evaluate the current taxonomy. Our data support only two taxa that correspond to the currently recognized subspecies M. p. proboscideus and M. p. flavicaudatus. Mitochondrial haplotypes of these two taxa are reciprocally monophyletic with over 13% uncorrected sequence divergence between them. PCA analysis of 14 morphological characters (mostly cranial) grouped the two taxa into non-overlapping clusters, and body mass alone is a relatively reliable distinguishing character throughout much of Macroscelides range. Although fieldworkers were unable to find sympatric populations, the two taxa were found within 50 km of each other, and genetic analysis showed no evidence of gene flow. Based upon corroborating genetic data, morphological data, near sympatry with no evidence of gene flow, and differences in habitat use, we elevate these two forms to full species.     

The mechanism of ciprofloxacin resistance in dihydrogen peroxide-induced mutants of Salmonella enterica subsp. enterica serovar typhimurium consists mainly in mutations in gyrA gene and less in mutations affecting ciprofloxacin uptake

The effect of H(2)O(2) on the induction of ciprofloxacin (CFL) resistant mutants of Salmonella enterica subsp. enterica serovar Typhimurium was evaluated and determinants of CFL resistance in the mutants were analyzed. Factors associated with CFL resistance in H(2)O(2)-induced mutants included (i) mutations in gyrA gene, predominantly (63 %) Asp(87)-->Asn and less (37 %) Ser(83)-->Phe substitutions, (ii) mutations in the regulatory genes of MarRAB or SoxRS or in the individual structural genes of these operons. Such mutations are induced by H(2)O(2) in a much lower extent. Reduced OmpF expression simultaneously with enhanced efflux was detected only in one mutant strain and 20 % of mutant strains had increased CFL efflux from the cells.     

Hybridization and population genetics of two macaque species in Sulawesi, Indonesia

This study investigates hybridization and population genetics of two species of macaque monkey in Sulawesi, Indonesia, using molecular markers from mitochondrial, autosomal, and Y-chromosome DNA. Hybridization is the interbreeding of individuals from different parental taxa that are distinguishable by one or more heritable characteristics. Because hybridization can affect population structure of the parental taxa, it is an important consideration for conservation management. On the Indonesian island of Sulawesi an explosive diversification of macaques has occurred; seven of 19 species in the genus Macaca live on this island. The contact zone of the subjects of this study, M. maura and M. tonkeana, is located at the base of the southwestern peninsula of Sulawesi. Land conversion in Sulawesi is occurring at an alarming pace; currently two species of Sulawesi macaque, one of which is M. maura, are classified as endangered species. Results of this study indicate that hybridization among M. maura and M. tonkeana has led to different distributions of molecular variation in mitochondrial DNA and nuclear DNA in the contact zone; mitochondrial DNA shows a sharp transition from M. maura to M. tonkeana haplotypes, but nuclear DNA from the parental taxa is homogenized in a narrow hybrid zone. Similarly, within M. maura divergent mitochondrial DNA haplotypes are geographically structured but population subdivision in the nuclear genome is low or absent. In M. tonkeana, mitochondrial DNA haplotypes are geographically structured and a high level of nuclear DNA population subdivision is present in this species. These results are largely consistent with a macaque behavioral paradigm of female philopatry and obligate male dispersal, suggest that introgression between M. maura and M. tonkeana is restricted to the hybrid zone, and delineate one conservation management unit in M. maura and at least two in M. tonkeana.     

COLEOFASCICULUS GEN. NOV. (CYANOBACTERIA): MORPHOLOGICAL AND MOLECULAR CRITERIA FOR REVISION OF THE GENUS MICROCOLEUS GOMONT1

Species currently classified within the cyanobacterial genus Microcoleus were determined to fall into two distinct clades in a 16S rDNA phylogeny, one containing taxa within the Oscillatoriaceae, the other containing taxa within the Phormidiaceae. The two lineages were confirmed in an analysis of the 16S–23S internal transcribed spacer (ITS) region sequences and secondary structures. The type species for Microcoleus is M. vaginatus Gomont, and this taxon belongs in the Oscillatoriaceae. Consequently, Microcoleus taxa in the Phormidiaceae must be placed in separate genera, and we propose the new genus Coleofasciculus to contain marine taxa currently placed in Microcoleus. The type species for Coleofasciculus is the well‐studied and widespread marine mat‐forming species Microcoleus chthonoplastes (Mert.) Zanardini ex Gomont. Other characters separating the two families include type of cell division and thylakoid structure.     

Dentition and histology in titanosaurian dinosaur embryos from Upper Cretaceous of Patagonia,Argentina

Abstract: Exceptionally preserved sauropod embryos from the Late Cretaceous Anacleto Formation in Auca Mahuevo (Neuquén Province, Argentina) have provided fundamental information on titanosaurian ontogeny. This paper describes the dental composition, disposition and microstructure of the specimens. Embryonic teeth show size disparity, with lengths that vary from 1 to 3 mm and diameters ranging from 0.15 to 0.26 mm, with the most frequent length values between 2.5 and 3 mm. Apparently, a typical ‘pencil‐like’ tooth morphology and a dental formula of Pm 4, M 7–8/D10? remained constant during titanosaurian ontogeny, whereas the arrangement of teeth in the skull shows notable ontogenetic changes. Absence of wear facets on teeth suggests a lack of prenatal chewing movements. The enamel proportion is significantly higher in embryos than in mature titanosaurs, which suggests that this relationship varies during ontogeny. Embryonic bony tissue is composed of highly vascularized, cellular woven bone. The absence of osteonal tissue, the high degree of vascularization, the presence of numerous osteocytes and poor development of periosteal bone reveals that the Auca Mahuevo titanosaurs would have had a high early growth rate and that they were buried at a relatively advanced embryonic stage.     

Molecular phylogenies in the genus Mus: Comparative analysis of electrophoretic, scnDNA hybridization, and mtDNA RFLP data

In this paper, we present data on murid rodents obtained by three major techniques used in biochemical systematics today: protein electrophoresis, scnDNA hybridization and mtDNA RFLP. The data have been analysed by both phenetic and cladistic methods and results of the three techniques were compared with one another. Four clear major levels of divergence (or nodes) can be recognized by all methods. Node 1 groups four subspecies of M. musculus ( domesticus, bactrianus, castaneus and musculus ). Node 2 groups four species: M. musculus, M. spretus, M. spicilegus and M. spretoides . Node 3 groups the stem of node 2 and three strictly Oriental species ( M. caroli, M. cervicolor and M. cookii ) Node 4 groups the previous lineages with Oriental Pyromys and Coelomys and the Ethiopian Nannomys . However, the relationships within each level cannot be resolved without ambiguity. We argue that this is not due to the resolutive power of our methods, but to a biological reality, that is successive adaptive radiations marked by quasi-simultaneous speciation events linked with geographical colonization. Our estimation of divergence time between different taxa showed that the genus Mus is very young. The youngest 'bona fide' species are 1.1 Myr old, or even less than 0.3 Myr if one takes into consideration the two sibling species M. spicilegus and M. spretoides . It appears that mtDNA evolves three to six times faster than scnDNA. The zoogeographical history of the genus can be reconstructed as a séries of adaptative radiations leading to the present day distribution of the Palaearctic, Oriental, and Ethiopian groups of taxa.     

猪CFL2b基因部分序列的克隆及组织表达谱分析

在猪QTL定位基础上,利用比较基因组学原理,参照猪CFL2的cDNA序列,对猪CFL2基因的部分基因组DNA序列进行克隆、测序;利用RT-PCR半定量法检测CFL2基因在不同组织的表达情况.结果显示,所克隆的CFL2基因部分基因组DNA序列长度为2 377bp,包括4个外显子和4个内含子,该基因mRNA序列与已报道的人CFL2b基因序列相似性为89%;猪CFL2基因在多种组织中均有表达,但在骨骼肌和心肌中表达丰度较高.结果表明,本研究成功测序了猪CFL2b基因部分基因组DNA序列,为进一步研究该基因与肌肉发育及生理功能的关系奠定了基础.     

A putative plant homolog of the yeast beta-1,3-glucan synthase subunit FKS1 from cotton (Gossypium hirsutum L.) fibers

A novel plant gene CFL1 was cloned from cotton (Gossypium hirsutum L.) fibers by expressed sequence tag (EST) database searching and 5'-RACE (rapid amplification of cDNA ends). This gene shows sequence homology with FKS1 which has been identified as the putative catalytic subunit of the yeast beta-1,3-glucan synthase. It encodes a protein (CFL1p) of 219 kDa with 13 deduced transmembrane helices and 2 large hydrophilic domains, one of which is at the N-terminus and the other in the internal region of the polypeptide. CFL1 displays 21% identity and 41% similarity to FKS1 at the amino acid level over its entire length, with 31% identity and 52% similarity for the hydrophilic central domain. Using RNA and protein blot analysis, CFL1 was found to be expressed at higher levels in cotton fibers during primary wall development. CFL1 also had a strong expression in young roots. Using a calmodulin (CaM)-gel overlay assay, the hydrophilic N-terminal domain of CFL1p was shown to bind to CaM, while the hydrophilic central domain did not. A putative CaM-binding domain, 16 amino acids long, was predicted in the hydrophilic N-terminal domain. Moreover, a product-entrapment assay demonstrated that a protein associated with an in vitro-synthesized callose pellet could be labeled by anti-CFL1 antibodies. Our finding suggests that CFL1 is a putative plant homolog of the yeast beta-1,3-glucan synthase subunit FKS1 and could be involved in callose synthesis.     

Lasanius,an exceptionally preserved Silurian jawless fish from Scotland

The fossil record of non-biomineralizing, soft-bodied taxa is our only direct evidence of the early history of vertebrates. A robust reconstruction of the affinities of these taxa is critical to unlocking vertebrate origins and understanding the evolution of skeletal tissues, but these taxa invariably have unstable and poorly supported phylogenetic positions. At the cusp between mineralized bony vertebrates and entirely soft-bodied vertebrates is the enigmatic Lasanius, a purported anaspid from the Silurian of Scotland. Interpretations of its affinity and significance are conflicted, principally because of its poorly understood anatomy due to taphonomic distortion and loss of soft-tissues. Here we use an array of modern techniques to reassess the anatomy of Lasanius via a comprehensive study of 229 complete and partial specimens. A new reconstruction clarifies the identity and position of preserved features, including paired sensory organs, a notochord, and digestive tract, supporting the vertebrate affinities of this genus. SEM-EDS trace element mapping suggests a bone-like composition of mineralized parts, but finds no evidence for mineralized dermal armour. Phylogenetic analysis recovers Lasanius as an early stem-cyclostome, and subsequent analysis supports the rejection of alternative placements (such as stem-gnathostome). We highlight that while distinguishing between the early cyclostome and gnathostome condition is problematic, increasing confidence in the anatomy of key taxa, such as Lasanius, is vital for increased stability throughout the early vertebrate tree.