Seasonal variation in oxygen isotope composition of waters for a montane larch forest in Mongolia

Measurements of water oxygen isotopic composition were conducted in the 2003 growing season for a montane larch (Larix sibirica Ledeb.) forest in northern Mongolia, a transitional area from the south Siberian taiga to the Asian steppe. Oxygen isotopic composition of foliar water and its daily variability were found to be sensitive to atmospheric evaporative demand. During most of the growing season, water sources used by larch trees were from the upper 30-cm surface layer of the soil when precipitation input was large, and were from the deeper layer when the water supply at the upper soil layer was limited. The Keeling plot method suggested that the forest returned soil water to the atmosphere predominantly by means of canopy transpiration during the peak growth period (in August).     

Hair Cells – Beyond the Transducer

Overview This review considers the “tween twixt and twain” of hair cell physiology, specifically the signaling elements and membrane conductances which underpin forward and reverse transduction at the input stage of hair cell function and neurotransmitter release at the output stage. Other sections of this review series outline the advances which have been made in understanding the molecular physiology of mechanoelectrical transduction and outer hair cell electromotility. Here we outline the contributions of a considerable array of ion channels and receptor signaling pathways that define the biophysical status of the sensory hair cells, contributing to hair cell development and subsequently defining the operational condition of the hair cells across the broad dynamic range of physiological function.     

Differential protein distributions define two sub-compartments of the mitochondrial inner membrane in yeast

The mitochondrial inner membrane exhibits a complex topology. Its infolds, the cristae membranes, are contiguous with the inner boundary membrane (IBM), which runs parallel to the outer membrane. Using live cells co-expressing functional fluorescent fusion proteins, we report on the distribution of inner membrane proteins in budding yeast. To this end we introduce the enlarged mitochondria of Deltamdm10, Deltamdm31, Deltamdm32, and Deltammm1 cells as a versatile model system to study sub-mitochondrial protein localizations. Proteins of the F(1)F(0) ATP synthase and of the respiratory chain complexes III and IV were visualized in the cristae-containing interior of the mitochondria. In contrast, proteins of the TIM23 complex and of the presequence translocase-associated motor were strongly enriched at the IBM. The different protein distributions shown here demonstrate that the cristae membranes and the IBM are functionally distinct sub-compartments.     

甘肃、新疆、内蒙苹果蠹蛾成虫消长规律

苹果蠹蛾Cydia pomonella(L.)是我国重要的果树害虫和检疫对象。2005年至2010年,本研究在甘肃、新疆及内蒙古的不同区县选取了16个果园,使用性信息素诱捕器对其中的苹果蠹蛾成虫发生规律进行长期监测。结果表明,苹果蠹蛾在西北地区每年发生2.5个世代;在正常气候条件下,3个成虫发生高峰分别出现在5月上旬、7月中下旬和8月中下旬,但不同地区及同一地区不同果园之间存在较大差异;化学防治、迷向防治等防治措施对苹果蠹蛾成虫捕获量的影响较大,因此生活史研究为主的监测并不适合在上述果园中开展。综合上述研究结果,未对苹果蠹蛾的季节动态进行准确的预测,需要对苹果蠹蛾除成虫外的其他虫态的季节性变化进行详细研究,并建议选择3个以上的果园进行监测,综合各个果园的监测结果并得出结论。     

The surf zone: a semi-permeable barrier to onshore recruitment of invertebrate larvae?

The supply of larvae to the shore is important for population replenishment and intertidal community dynamics but its variability at most scales is not well understood. We tested the relationship between nearshore mussel larval abundance and intertidal settlement rates over several years at multiple spatiotemporal scales in Oregon and New Zealand. Abundance of competent larvae nearshore and intertidal recruitment rates were simultaneously quantified using collectors mounted at different depths on moorings 50-1100 m from shore, and at adjacent rocky intertidal sites. Total mussel larval abundance and oceanographic conditions were also measured in some locations. At all scales, abundance of nearshore mussel larvae was unrelated to intertidal recruitment rates. In the intertidal, patterns of mussel recruitment were persistent in space, with sites of consistently high or low recruitment. In contrast, nearshore competent larval abundance showed generally similar abundances among sites except for a high, and spatially-inconsistent, variability in Oregon during 1998 only. On moorings, recruitment tended to be greater on midwater collectors than shallower or deeper. Finally, on moorings larval abundance in traps and recruitment on collectors was unrelated. These results suggest that (1) among sites, the size of the nearshore larval pool is relatively uniform while onshore recruitment varies and is unrelated to larval abundance, (2) temporal variability in nearshore larval availability is not strongly expressed onshore, (3) vertical stratification of competent larvae nearshore is strong and may influence transport and recruitment, and (4) within-coast variability in onshore recruitment is strongly driven by processes occurring locally within the surf zone that need to be studied to understand coastal recruitment dynamics.     

Distribution of RNA binding protein MOEP19 in the oocyte cortex and early embryo indicates pre-patterning related to blastomere polarity and trophectoderm specification

We report the cloning and characterization of MOEP19, a novel 19 kDa RNA binding protein that marks a defined cortical cytoplasmic domain in oocytes and provides evidence of mammalian oocyte polarity and a form of pre-patterning that persists in zygotes and early embryos through the morula stage. MOEP19 contains a eukaryotic type KH-domain, typical of the KH-domain type I superfamily of RNA binding proteins, and both recombinant and native MOEP19 bind polynucleotides. By immunofluorescence, MOEP19 protein was first detected in primary follicles throughout the ooplasm. As oocytes expanded in size during oogenesis, MOEP19 increased in concentration. MOEP19 localized in the ovulated egg and early zygote as a symmetrical spherical cortical domain underlying the oolemma, deep to the zone of cortical granules. MOEP19 remained restricted to a cortical cytoplasmic crescent in blastomeres of 2-, 4- and 8-cell embryos. The MOEP19 domain was absent in regions underlying cell contacts. In morulae, the MOEP19 domain was found at the apex of outer, polarized blastomeres but was undetectable in blastomeres of the inner cell mass. In early blastocysts, MOEP19 localized in both mural and polar trophectoderm and a subset of embryos showed inner cell mass localization. MOEP19 concentration dramatically declined in late blastocysts. When blastomeres of 4- to 8-cell stages were dissociated, the polarized MOEP19 domain assumed a symmetrically spherical localization, while overnight culture of dissociated blastomeres resulted in formation of re-aggregated embryos in which polarity of the MOEP19 domain was re-established at the blastomere apices. MOEP19 showed no evidence of translation in ovulated eggs, indicating that MOEP19 is a maternal effect gene. The persistence during early development of the MOEP19 cortical oocyte domain as a cortical crescent in blastomers suggests an intrinsic pre-patterning in the egg that is related to the apical-basolateral polarity of the embryo. Although the RNAs bound to MOEP19 are presently unknown, we predict that the MOEP19 domain directs RNAs essential for normal embryonic development to specific locations in the oocyte and early embryo.     

Inner city stormwater control using a combination of best management practices

Structural best management practices (BMPs) are now commonplace for stormwater management in new suburban developments; however, their installation in older central areas is limited. Here, the effect of disconnecting impervious areas from a combined sewer in favour of a new open stormwater system is investigated. The site, an inner city suburb of Malmö, Sweden, consists of council offices and apartment blocks separated by courtyards, roads and parking places. The BMPs range from green-roofs and open channels to detention ponds and their choice, size and location was dictated by cost, available land, safety and public expectations. The system was assessed by comparing synthetic hydrographs for the 1/2, 2, 5 and 10-year design-storms assuming wet and dry initial conditions. Direct runoff was simulated using the time–area method; and routing through the BMPs using PondPack. As the BMPs are in series, the outflow of one BMP became part of the inflow to the next in the system. Additionally, the water balance for the year 2001–2002 was investigated. It was found that the green-roofs are effective at lowering the total runoff from Augustenborg and that the ponds should successfully attenuate storm peak flows for even the 10-year rainfall.     

Structural and Functional Grounds for Ephedra sinica Expansion in Mongolian Steppe Ecosystems

Morphological and structural characteristics of photosynthetic organs, diurnal changes in photosynthetic and transpiration rates, and the efficiency of water use were studied in three plant species from mountain-steppe ecosystems in Mongolia, Ephedra sinica Stapf, Stipa glareosa P. Smirn., and Allium polyrhizum Furcz. ex Regel. The species studied differed in the structural and functional mechanisms for the adaptation of photosynthetic apparatus to arid conditions. E. sinica has thick, vertical assimilating shoots, which are characterized by a high density (620 mg/cm³) and a small proportion of photosynthetic tissues (13%). The proportion of meso-phyll in the leaves of A. polyrhizum and S. glareosa was two and three times higher, respectively. The low content of phototrophic tissues in E. sinica shoot was compensated for by a high photosynthetic activity of single chloroplasts (25 mg CO₂/(10⁹ chloroplast h)), which was six times higher, than in two other species. Daily course of photosynthesis and transpiration inE. sinica differed from those of A. polyrhizum and S. glareosa by the absence of the midday depression. E. sinica had the highest efficiency of water use (45 mg CO₂/g H₂O) due to a low transpiration rate (0.25 g/g fr wt h). It is concluded that, in E. sinica, the main strategy for adaptation to arid stress is to develop in the shoot a few photosynthesizing cells of high assimilation activity. Such structural organization of photosynthetic organs in ephedra contributes to its higher efficiency of water use and stability of physiological characteristics under changing environmental conditions. These specific features of the structure of assimilating organs and their functional features contribute to a greater expansion of E. sinica with increasing climate aridization in Mongolia.     

Sphenobaiera ikorfatensis (Seward) Florin from the Lower Cretaceous of Huolinhe, eastern Inner Mongolia, China

Sphenobaiera ikorfatensis (Seward) Florin from the Lower Cretaceous Huolinhe Formation in the Huolinhe coal–mining area, eastern Inner Mongolia, China, is identified, described and figured. Comparison with the type material of Sphenobaiera ikorfatensis (Seward) Florin from West Greenland confirms its identity. About 20 Chinese leaf specimens are known with well preserved cuticle which is closely similar to the Greenland leaves but more papillate. The palaeoclimatic and phytogeographic significance of the occurrence of this species is discussed in relation to the suggestion that West Greenland, north–east China and eastern Siberia were in the same phytogeographic region during the Lower Cretaceous.