Estimating fossil biomass from skeletal mass in marine invertebrates

Palaeoecology uses the numerical abundance and the occurrence of species to evaluate the dynamics of past communities, but biomass – the quantity of soft tissue – is the critical currency needed to capture the flow and role of nutrients in modern ecosystems. Acquiring biomass data from fossil assemblages has, however, remained challenging, thus limiting the analysis of net secondary production in palaeocommunities. Prior models relate shell size or shell biovolume to fossil biomass. These models neglect shell fragments and, moreover, use units of biovolume (cm³) that are not directly related to those of biomass (g), making the models difficult to tune and the coefficients highly specific. To remedy these shortcomings, I evaluate skeletal mass as a means of estimating the soft tissue biomass of fossil taxa, using ratios among biomass, skeletal mass and the total wet mass of living representatives of extant species, so that skeletal mass alone can be used to estimate grams of organic biomass. Data on total wet mass, organic carbon mass, and shell mass were acquired from more than 80 live‐collected individuals from eight families in three major, shelly macrobenthic groups (Mollusca, Brachiopoda, Arthropoda) and supplemented with counterpart data from the literature to increase taxonomic breadth. This new shell‐mass model provides more accurate and precise biomass estimates than models based on the linear dimensions of shells, expanding our ability to examine the interplay between organisms and their environments.     

Endothelial Nitric Oxide Synthase Deficient Mice Are Protected from Lipopolysaccharide Induced Acute Lung Injury

Lipopolysaccharide (LPS) derived from the outer membrane of gram-negative bacteria induces acute lung injury (ALI) in mice. This injury is associated with lung edema, inflammation, diffuse alveolar damage, and severe respiratory insufficiency. We have previously reported that LPS-mediated nitric oxide synthase (NOS) uncoupling, through increases in asymmetric dimethylarginine (ADMA), plays an important role in the development of ALI through the generation of reactive oxygen and nitrogen species. Therefore, the focus of this study was to determine whether mice deficient in endothelial NOS (eNOS^-/-) are protected against ALI. In both wild-type and eNOS^-/- mice, ALI was induced by the intratracheal instillation of LPS (2 mg/kg). After 24 hours, we found that eNOS^-/-mice were protected against the LPS mediated increase in inflammatory cell infiltration, inflammatory cytokine production, and lung injury. In addition, LPS exposed eNOS^-/- mice had increased oxygen saturation and improved lung mechanics. The protection in eNOS^-/- mice was associated with an attenuated production of NO, NOS derived superoxide, and peroxynitrite. Furthermore, we found that eNOS^-/- mice had less RhoA activation that correlated with a reduction in RhoA nitration at Tyr³⁴. Finally, we found that the reduction in NOS uncoupling in eNOS^-/- mice was due to a preservation of dimethylarginine dimethylaminohydrolase (DDAH) activity that prevented the LPS-mediated increase in ADMA. Together our data suggest that eNOS derived reactive species play an important role in the development of LPS-mediated lung injury.     

The molecular diversity of the methanogenic community in a hypereutrophic freshwater lake determined by PCR-RFLP

AIMS: To combine database-held sequence information with a programme of experimental molecular ecology to define the methanogenic community of a hypereutrophic lake by a PCR-restriction fragment length polymorphism (RFLP) analysis. METHODS AND RESULTS: Methanogen diversity in a hypereutrophic freshwater lake was analysed using 16S rDNA PCR-RFLP. Database-held 16S rRNA gene sequences for 76 diverse methanogens were analysed for specific restriction sites that permitted unequivocal differentiation of methanogens. Restriction digestion and agarose gel electrophoresis of the 16S rDNA from selected methanogen pure cultures generated observed restriction profiles that corroborated the expected patterns. This method was then tested by analysing methanogen diversity in samples obtained over 1 year from sediment and water samples taken from the same sampling site. CONCLUSIONS: Restriction analysis of the 16S rRNA gene sequences from 157 methanogen clones generated from lakewater and sediment samples showed that over 50% were similar to Methanoculleus spp. Furthermore, a total of 16 RFLP types (1-16) were identified, eight of which contained no cultured representative archaeal 16S rRNA gene sequences. SIGNIFICANCE AND IMPACT OF THE STUDY: This RFLP strategy provides a robust and reliable means to rapidly identify methanogens in the environment.     

Culture of bovine embryos after invitro exposure to Brucellaabortus

Fifty-four day-6 through day-10 (estrus=day 0) embryos were collected nonsurgically from 13 superovulated, brucellosis-free mixed breed cows. Forty-eight excellent and good zona pellucida-intact (ZP-I), three zona pellucida-defective (ZP-D), and three zona pellucida-free (ZP-F) embryos were incubated in media containing $\text{Brucella}$$\text{abortus}$. Subsequently, embryos were washed ten times in groups of one, two, three, or four. Embryos and serial washes were cultured for $\text{B}$. $\text{abortus}$.Brucellae were not isolated from any ZP-I embryo or from any washing beyond the sixth serial wash. Brucellae were not isolated from the three ZP-F embryos but were detected in the eighth wash for one and in the tenth wash for the others. Brucellae were isolated from one of three ZP-D embryos. Results show that ZP-I embryos can be effectively washed free of $\text{B}$. $\text{abortus}$.     

Early Tertiary fossil plants and paleoclimate of Lanzhou Basin

Fossil plants from the lower part of Xianshuihe Formation in the Lanzhou Basin, Gansu Province were studied. The flora contains 29 species, representing 20 genera and 12 families, which include Lauraceae ( Daphnogene ), Lardizabalaceae ( Akebia ), Berberidaceae ( Berberis ), Ulmaceae ( Planera, Ulmus, Zelkova ), Betulaceae ( Alnus, Carpinus ), Myricaceae( Myrica ), Salicaceae ( Populus, Salix), Myrsinaceae(Ardisia), Rosaceae ( Prunus, Sorbus, Sorbaria, Spiraea ), Leguminosae ( Gleditsia, Sophora), Anacardiaceae (Rhus), Caprifoliaceae(Viburnum). An analysis of the floristic elements and their foliar physiognomy shows that most members of the flora are deciduous broad-leaved trees or shrubs with a few evergreen shrubs. The most noteworthy species is Rhus turcomanica which was present in the Middle Eocene to Late Eocene of Central Asia (Kazakhstan, Turkmenistan). Generally, Rhus turcomanica occurred at the same beds as Palibinia, an extinct fossil plant whose presence indicates a subtropical dry climate. Another species, Sorbaria callicomifolia Kornilova was present from the Early Oligocene to Early Miocene of Central Asia (Kazakhstan and Turkmenistan). According to an analysis of spores and pollen, this flora contains over 20 species. It is predominated by the angiosperm pollen. There appeared Ephedripites and Nitrariadites which were important elements in the dry area. Ephedripites was found from the Upper Cretaceous to Early Tertiary. Nitrariadites occurred in the Late Miocene, whereas Rhus turcomanica and Sorbaria callicomifolia were both reported in the subtropical dry area from the Middle Eocene to Early Oligocene. The latest record of Rhus turcomanica is from the Middle Eocene to Early Oligocene of Central Asia. The presence of this element in the lower part of Xianshuihe Formation may indicate that itsage is the latest stage of the Early Oligocene.     

κ-卡拉胶琥珀酰基化衍生物的抗氧化活性研究

对κ-卡拉胶进行酸降解得到三种卡拉胶低聚糖,并进一步琥珀酰基化得到分子量分别为2720、4000和5960的κ-卡拉胶琥珀酰衍生物(A、B和C)。对产物进行FT-IR表征,并测得其琥珀酰基取代度(DS)分别为0.61、0.29和0.83。检测了三种κ-卡拉胶琥珀酰衍生物对超氧阴离子自由基O2.-、DPPH自由基、羟基自由基.OH以及过氧化氢的清除活性。结果表明:随着取代度的增加,其清除超氧阴离子自由基O2.-和DPPH自由基的能力增强;随着分子量的增加,其清除羟基自由基.OH和过氧化氢的能力增强。这可能与衍生物的羟基含量、取代基团的性质以及取代度等因素有关。     

Distribution of amiloride-sensitive sodium channels in the oral cavity of the hamster

The distribution of amiloride-sensitive sodium channels (ASSCs) in taste buds isolated from the oral cavity of hamsters was assessed by patch clamp recording. In contrast to the case for rats, taste cells from the fungiform, foliate and vallate papillae and from the soft palate all contain functional ASSCs. The differential distribution of ASSCs between the hamster and the rat may be important for understanding the physiology underlying the differing behavioral responses of these species to sodium salts.