Metabolic requirements for deactivation of insulin-stimulated glucose transport in isolated rat adipocytes

We have studied the rate of deactivation of the insulin-stimulated glucose transport system following the removal of insulin. Under all conditions, dissociation of insulin from its receptor proceeded much more rapidly than deactivation of the glucose transport system, indicating that deactivation was not simply a passive process reflecting a decline in receptor occupancy. The results demonstrate that deactivation of the glucose transport system is dependent upon ongoing cellular metabolism, and that this process occurs in a normal manner when a variety of substrates (glucose, fructose, or pyruvate) are available to the cells. When no substrate was present, then transport remained at or near the fully stimulated level. In an attempt to localize which metabolic sequence is involved in mediating glucose transport deactivation, studies were performed in the presence of a variety of substrates, inhibitors, and combinations of the two. NaF and citrate had marked effects to inhibit the normal rate of deactivation in the presence of glucose, whereas DNP had no effect on the rate of deactivation in the presence of added glucose. Pyruvate is a substrate which enters the glycolytic pathway distal to the site of action of NaF or citrate in the glycolytic pathway, and in the presence of pyruvate, the inhibiting effects of NaF and citrate on the rate of deactivation were abolished. These results demonstrate that deactivation of the insulin-stimulated glucose transport system is an active process dependent upon some aspect of cellular glucose metabolism. It is likely that the important metabolic step is distal to the point at which pyruvate enters the glycolytic pathway and possibly proximal to the step at which DNP inhibits mitochondrial oxidative phosphorylation.     

The Banana Forests of Kilimanjaro: Biodiversity and Conservation of the Chagga Homegardens

Natural flora, vegetation, diversity and structure of 62 traditional coffee–banana plantations on Kilimanjaro were investigated and compared with the other vegetation formations on this volcano on basis of over 1400 plots following the method of Braun-Blanquet. The vegetation of the so-called Chagga homegardens belongs floristically to the formation of ruderal vegetation forming two main communities that are determined by altitude. These coffee–banana plantations maintain a high biodiversity with about 520 vascular plant species including over 400 non-cultivated plants. Most species (194) occurring in the Chagga homegardens are forest species, followed by 128 ruderal species, including 41 neophytes. Typical of the agroforestry system of the Chagga homegardens is their multilayered vegetation structure similar to a tropical montane forest with trees, shrubs, lianas, epiphytes and herbs. Beside relicts of the former forest cover, which lost most of their former habitats, there are on the other hand (apophytic) forest species, which were directly or indirectly favoured by the land use of the Chagga people. High demand of wood, the introduction of coffee varieties that are sun-tolerant and low coffee prizes on the world marked endanger this effective and sustainable system.     

东海表层沉积中的翼足类及其地质意义

对东海84个表层沉积中翼足类进行了定量分析,共获得7属15种,其中Limacinainflata在陆架外缘和上陆坡为优势种,Limacinatrochi formis,Creseisacicula和Creseis virgule在中外陆架最为丰富。根据翼足类的深度分布确定东海现代文石补偿深度在约600m水深处。以冲绳海槽北部柱状样B3GC为例,说明翼足类是研究地质时期古海洋学变化的重要证据。     

Simulating climate change impacts on forests and associated vascular epiphytes in a subtropical island of East Asia

Aim This study aims to assess the impact of climate change on forests and vascular epiphytes, using species distribution models (SDMs). Location Island of Taiwan, subtropical East Asia. Methods A hierarchical modelling approach incorporating forest migration velocity and forest type–epiphyte interactions with classical SDMs was used to model the responses of eight forest types and 237 vascular epiphytes for the year 2100 under two climate change scenarios. Forest distributions were modelled and modified by dominant tree species’ dispersal limitations and hypothesized persistence under unfavourable climate conditions (20 years for broad‐leaved trees and 50 years for conifers). The modelled forest projections together with 16 environmental variables were used as predictors in models of epiphyte distributions. A null method was applied to validate the significance of epiphyte SDMs, and potential vulnerable species were identified by calculating range turnover rates. Results For the year 2100, the model predicted a reduction in the range of most forest types, especially for Picea and cypress forests, which shifted to altitudes c. 400 and 300 m higher, respectively. The models indicated that epiphyte distributions are highly correlated with forest types, and the majority (77–78%) of epiphyte species were also projected to lose 45–58% of their current range, shifting on average to altitudes c. 400 m higher than currently. Range turnover rates suggested that insensitive epiphytes were generally lowland or widespread species, whereas sensitive species were more geographically restricted, showing a higher correlation with temperature‐related factors in their distributions. Main conclusions The hierarchical modelling approach successfully produced interpretable results, suggesting the importance of considering biotic interactions and the inclusion of terrain‐related factors when developing SDMs for dependant species at a local scale. Long‐term monitoring of potentially vulnerable sites is advised, especially of those sites that fall outside current conservation reserves where additional human disturbance is likely to exacerbate the effect of climate change.     

Improved culturability of SAR11 strains in dilution-to-extinction culturing from the East Sea, West Pacific Ocean

Although the SAR11 clade of the Alphaproteobacteria represents the most abundant and ubiquitous bacterioplankton in the ocean, very few laboratories have successfully cultured SAR11 cells. All of the SAR11 strains isolated thus far have been retrieved from the Oregon coast and the Sargasso Sea. In this study, a modified dilution-to-extinction culturing with prolonged incubation at low temperature was applied in an effort to cultivate major bacterioplankton lineages in the East Sea, Western Pacific Ocean. Five to 10 cells were inoculated into each well of 48-well plates, followed by the incubation of the plates at 10 °C for 4, 8, 20, and 24 weeks. Among a total of 35 isolated strains, 18 strains assigned to the SAR11 clade were isolated after 8, 20, and 24 weeks of incubation, whereas no SAR11 cells were detected in the samples after 4 weeks of incubation. The SAR11 isolates, noticeably, comprised 64–82% of the total isolates from the plates incubated for 20 and 24 weeks. Extinction cultures belonging to the Roseobacter , OM43, and SAR92 clades were also cultivated. The results of this study suggest that long-term incubation at low temperatures might prove an alternative for the efficient cultivation of new variants of the members of the SAR11 clade.     

The formation of iron plaques on roots and rhizomes of the seagrass Cymodocea serrulata (R. Brown) Ascherson with implications for sulphide intrusion

Despite the fact that iron plaque formation is ubiquitous in aquatic macrophytes and has been known for several decades, there are few reports of plaque occurrence in seagrasses to date. Herein we present the first microscopical observation and chemical quantification of iron (Fe) plaques on the shoots, rhizomes and roots of the seagrass Cymodocea serrulata (R. Brown) Ascherson collected from intertidal seagrass beds in Thailand. Plaques were observed on shoot bases, rhizomes and roots with the highest concentrations of iron in the plaques from the roots, reaching an average of 509 μmol gDW⁻¹. Interestingly, the most negative stable sulphur isotope (δ³⁴S) values, indicating H₂S intrusion into the plants occurred in the sampling site with the most intense root oxidizing capacity, as indicated by a greater Fe plaque formation. These apparently contradictory findings may be attributed to oxidizing capacity of root tips and root hairs sufficient to promote Fe(III) deposition in the rhizosphere, preceding deposition of plaques on the roots. While this rhizosphere oxidation may result in a more efficient sulphide detoxification during the day photosynthetic phase, root tips and hairs may serve as vulnerable sites for sulphide intrusion at night. The presence of Fe plaque on C. serrulata roots and rhizomes reveals the complexity of seagrass–sediment interactions and deserves further attention to understand if this is a local phenomenon or a newly discovered adaptive mechanism in seagrasses.     

Assessment of tree-ring analysis of high-elevation Cedrus deodara D. Don from Western Himalaya (India) in relation to climate and glacier fluctuations

A 458-year-long regional tree-ring-width index chronology of Himalayan cedar (Cedrus deodara D. Don) prepared from three high-elevation sites of Western Himalaya has been presented. Dendroclimatological investigation indicates significant positive relationship of tree-ring index series with winter (December–February) temperature and summer precipitation and inverse relationship with summer temperature. Higher growth in the recent few decades detected in the tree-ring chronology has been noticed coinciding with the rapid retreat of the Himalayan glaciers. Suppressed and released growth patterns in tree-ring chronology have also been observed to be well related to the past glacial fluctuation records of the region. The higher tree growth in recent decades may be partially attributed to the warming trend over the region, particularly increasing the winter warmth, and thus to the regional manifestations of global warming.     

Taxonomy and molecular phylogeny of the Asian Paraleucophenga Hendel (Diptera,Drosophilidae)

This paper reports on nine Asian species of the genus Paraleucophenga, of which four are new to science: Paraleucophenga brevipenis sp. nov. , Paraleucophenga hirtipenis sp. nov. , Paraleucophenga longiseta sp. nov. , and Paraleucophenga tanydactylia sp. nov. We also report on a new synonym, Paraleucophenga shanyinensis Chen & Toda, 1994 syn. nov. A key to all of the species examined, based on morphological data, is provided, together with a ‘molecular’ key to seven Paraleudophenga species based on DNA sequence data of the mitochondrial NADH dehydrogenase subunit 2 (ND2) gene. The phylogenetic relationships among seven Paraleucophenga species are reconstructed based on DNA sequences of the mitochondrial ND2 gene, using two Leucophenga species as outgroups. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 615–629.     

Type specimens of G. E. Post in Beirut and The Natural History Museum,London

The Flora of Syria, Palestine and Sinai, a pioneer Flora of the region, was published in 1896 by George Edward Post (1838–1909). Lesser known are his series of Diagnoses plantarum novarum orientalium, published in the Journal of the Linnean Society Botany, and 10 papers, Plantae Postianae, which appeared in Swiss journals from 1890 to 1900. A greatly expanded second edition of the Flora was prepared by John Edward Dinsmore and published in Beirut in 1932 and 1933. Post's plant collection is part of the Post Herbarium (BEI), with about 63 000 specimens, that has been well maintained, despite civil war and inadequate staffing. This work involves the identification of around 150 types in BEI and BM, and improvement of the accessibility of the specimens. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 315–321.     

Morphogenesis,origin, and paleoecology of the bryozoans of the family Medvedkellidae fam. nov. (Upper Carboniferous,East European Platform)

A new family of the order Rhabdomesida, Medvedkellidae fam. nov., is described. This family consists of a new genus, Medvedkella gen. nov., comprising three species transferred from the genus Rhombopora Meek, 1872: the type species M. riasanensis (Schulga-Nesterenko, 1955), M. diaphragmata (Schulga-Nesterenko, 1955), and M. mariae (Dunaeva, 1961). The morphogenesis of the first two species is studied. For the first time axial zooecia are revealed in the suborder Golgdfussitrypina, which existed in parallel with the suborder Rhabdomesina of the order Rhabdomesida. A hypothesis that the new family evolved from the subfamily Nicklesoporinae Gorjunova, 1985 of the family Goldfussitrypidae, 1985 is proposed. Some questions of the ecological adaptation of these bryozoans in the Late Carboniferous marine basin of the East European Platform are discussed.