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First Detailed Description (first + detailed_description)
Selected AbstractsCrystal structure of archaeal highly thermostable L -aspartate dehydrogenase/NAD/citrate ternary complexFEBS JOURNAL, Issue 16 2007Kazunari Yoneda The crystal structure of the highly thermostable l -aspartate dehydrogenase (l -aspDH; EC 1.4.1.21) from the hyperthermophilic archaeon Archaeoglobus fulgidus was determined in the presence of NAD and a substrate analog, citrate. The dimeric structure of A. fulgidusl -aspDH was refined at a resolution of 1.9 Å with a crystallographic R -factor of 21.7% (Rfree = 22.6%). The structure indicates that each subunit consists of two domains separated by a deep cleft containing an active site. Structural comparison of the A. fulgidusl -aspDH/NAD/citrate ternary complex and the Thermotoga maritimal -aspDH/NAD binary complex showed that A. fulgidusl -aspDH assumes a closed conformation and that a large movement of the two loops takes place during substrate binding. Like T. maritimal -aspDH, the A. fulgidus enzyme is highly thermostable. But whereas a large number of inter- and intrasubunit ion pairs are responsible for the stability of A. fulgidusl -aspDH, a large number of inter- and intrasubunit aromatic pairs stabilize the T. maritima enzyme. Thus stabilization of these two l -aspDHs appears to be achieved in different ways. This is the first detailed description of substrate and coenzyme binding to l -aspDH and of the molecular basis of the high thermostability of a hyperthermophilic l -aspDH. [source] Larynx morphology and sound production in three species of TestudinidaeJOURNAL OF MORPHOLOGY, Issue 2 2004Roberto Sacchi Abstract Although the ability to vocalize is widespread among tortoises, the mechanisms of sound production in chelonians remain undescribed. In this study, we analyze the morphology and histology of the larynx of three species of Testudinidae (Testudo hermanni, T. graeca, and T. marginata) in order to ascertain the presence of vibrating acoustic structure, and based on our findings we propose a general model for phonation in tortoises. The structure of the larynx of the three tortoises analyzed is simple: three cartilages (the cricoid and two arytenoids) form the skeleton of the larynx, while two pairs of muscles (the dilators and constrictors) control the widening and closing of the glottis. The larynx is supported in the oral cavity by the hyoid cartilage, which in tortoises assumes the same functions of the thyroid cartilage of mammals. Two bands of elastic fibers are inserted in the lateral walls of the larynx just upstream of the glottis, and can be stretched away from the hyoid by the movements of the arytenoids. Their position and structure suggest that these bands are capable of vibrating during exhalation, and therefore may be considered vocal cords. The cricoid of T. marginata and T. graeca hold two diverticula, not previously reported, which might function as a low-frequency resonating chamber, improving the harmonic structure of tortoise calls. The structure of the larynx is compared with that of other vertebrates and the relationships between morphology and phonation are discussed. This is the first detailed description of anatomical structures possibly devoted to vocalization in chelonians. J. Morphol. 261:175,183, 2004. © 2004 Wiley-Liss, Inc. [source] Spawning of a Captive Population of California Sheephead, Semicossyphus pulcherJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2007Dave Jirsa This study represents the first detailed description of spawning and patterns of egg production in a captive population of California sheephead. In March 2004, females ranged in size from 369 to 430 mm total length (TL) and weighed 0.8,1.5 kg. Males ranged in size from 475 to 510 mm TL and weighed 1.7,2.3 kg. Spawning began in April and continued daily through September and then sporadically through October. Egg production ranged from 1000 to 375,000 eggs/d, with an average of 130,000 eggs/d. Egg production peaked in May at 222,000 eggs/d and decreased throughout the remainder of the season. Total annual fecundity from this group was 1,942,000 eggs/kg female body weight. Egg viability ranged from 0 to 80% with an average of 50%. Viability showed a general increase at the beginning of the season and a decrease at the end of the season. Eggs were 0.9,1.0 mm in diameter and hatched in approximately 48 h at 18,19 C. Hatch rates showed a general decline throughout the season. This study shows that California sheephead will spawn readily in captivity providing thousands of viable eggs daily and lays the groundwork for culture of this species. [source] First description of the surgical anatomy of the cynomolgus monkey liverAMERICAN JOURNAL OF PRIMATOLOGY, Issue 5 2009Corinne Vons Abstract No detailed description of nonhuman primate liver anatomy has been reported and little is known about the similarity between such livers and human liver. The cynomolgus monkey (Macaca fascicularis) was used to establish a preclinical model of genetically modified hepatocytes auto transplantation. Here, we report information gleaned from careful observation and notes obtained from 59 female cynomolgus monkeys undergoing 44 anatomical hepatic resections, 12 main portal vein division dissections and selective branch ligations, and 46 portographies. Additionally, three anatomical liver dissections after total resection at autopsy were performed and served to confirm peroperative observations and for photography to provide illustrations. Our results indicate that the cynomolgus monkey liver has four lobes: the median (the largest), the right and left lateral, and the caudate lobes. In 60% (N=20) of individuals the portal bifurcates into right and left portal veins, in the remaining 40% (N=14) the portal vein trifurcates into right anterior, right posterior, and left portal veins. The anatomy and branching pattern of the hepatic artery and bile ducts closely follow those of the portal branches. Functionally, the cynomolgus monkey liver can be divided into eight independent segments. Thus, we report the first detailed description of the hepatic and portal surgical anatomy of the cynomolgus monkey. The cynomolgus monkey liver is more similar to the human liver than are livers of any small or large nonprimate mammals that have been described. Am. J. Primatol. 71:400,408, 2009. © 2009 Wiley-Liss, Inc. [source] Morphology and Histology of the Atlantic Bottlenose Dolphin (Tursiops truncatus) Adrenal Gland with Emphasis on the MedullaANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2005L. S. Clark Summary This study provides the first detailed description of the Atlantic bottlenose dolphin (Tursiops truncatus) adrenal gland with emphasis on the medulla. Thirty-one dolphins of varying age and sex were used in this study. No statistical differences were found between the right and left gland mass, however, the left was typically greater. Mean mass for the right and left adrenal glands were 4.99 ± 0.513 and 5.36 ± 0.558 g, respectively. No statistical differences were found between average gland mass and sexual maturity or sex. The average cortex/medulla ratio was 1.22 ± 0.060 meaning approximately 48% is cortex, 41% is medulla, and 11% was categorized as other (i.e. blood vessels, connective tissue, etc.). The cortex contained pseudolobules and the typical zonation. A medullary band, consisting of highly basophilic staining cells was found at the periphery of the medulla. Projections of the medulla to the gland capsule were noted. Immunolabelling with polyclonal antibodies against the enzymes dopamine , hydroxylase and phenylethanolamine N-methyl transferase indicated that noradrenaline producing cells are found throughout the medulla including the medullary band while adrenaline producing cells are only found within the medullary band. Transmission electron microscopy confirmed the presence of two distinct cell populations within the medullary band and a single cell population throughout the medulla. [source] Late Quaternary distribution and biogeography of the southern Lake Eyre basin (SLEB) megafauna, South AustraliaBOREAS, Issue 1 2009STEVE WEBBArticle first published online: 3 SEP 200 Understanding the population demography, species distribution and biogeography of Australia's megafauna is essential for understanding their extinction. This process is only just beginning, and this article discusses these aspects while concentrating on a particular region; the southern Lake Eyre Basin (SLEB). It is also the first detailed description of the distribution of megafauna across that region of central Australia. The data are based on an extensive longitudinal study of 41 palaeontological sites spread across 250 000 km2. Megafauna adaptation and response to extensive environmental change during the late Quaternary is reflected in the composition and distribution of 21 megafauna species found across the region. A flexible migration strategy in response to wet/arid cycles saw occupation focusing on riverine and lacustrine environments formed by episodes of southerly monsoon incursion into the northern Lake Eyre basin. The supply of animals to the area was largely derived from endemic populations inhabiting western parts of southeastern Australia, where the majority of SLEB species are also found. Diprotodon reflects the adaptive flexibility of some species owing to its particular continental distribution, with a number of semi-arid regions across the continent. A picture of how and when the last of the region's megafauna disappeared is closer to being understood, with likely terminal dates for Genyornis and Diprotodon now available. [source] External genital morphology of the ring-tailed lemur (Lemur catta): Females are naturally "masculinized"JOURNAL OF MORPHOLOGY, Issue 4 2008Christine M. Drea Abstract The extravagance and diversity of external genitalia have been well characterized in male primates; however, much less is known about sex differences or variation in female form. Our study represents a departure from traditional investigations of primate reproductive anatomy because we 1) focus on external rather than internal genitalia, 2) measure both male and female structures, and 3) examine a strepsirrhine rather than an anthropoid primate. The subjects for morphological study were 21 reproductively intact, adult ring-tailed lemurs (Lemur catta), including 10 females and 11 males, two of which (one per sex) subsequently died of natural causes and also served as specimens for gross anatomical dissection. Male external genitalia presented a typical masculine configuration, with a complex distal penile morphology. In contrast, females were unusual among mammals, presenting an enlarged, pendulous external clitoris, tunneled by the urethra. Females had a shorter anogenital distance and a larger urethral meatus than did males, but organ diameter and circumference showed no sex differences. Dissection confirmed these characterizations. Noteworthy in the male were the presence of a "levator penis" muscle and discontinuity in the corpus spongiosum along the penile shaft; noteworthy in the female were an elongated clitoral shaft and glans clitoridis. The female urethra, while incorporated within the clitoral body, was not surrounded by erectile tissue, as we detected no corpus spongiosum. The os clitoridis was 43% the length and 24% the height of the os penis. On the basis of these first detailed descriptions of strepsirrhine external genitalia (for either sex), we characterize those of the female ring-tailed lemur as moderately "masculinized." Our results highlight certain morphological similarities and differences between ring-tailed lemurs and the most male-like of female mammals, the spotted hyena (Crocuta crocuta), and call attention to a potential hormonal mechanism of "masculinization" in female lemur development. J. Morphol., 2008. © 2007 Wiley-Liss, Inc. [source] | |||||||||||||