bluuebunny/crossref_metadata_2025 huggingface dataset:
Dispersal, recruitment and migratory behaviour in a hawksbill sea turtle aggregation
Authors: VELEZ‐ZUAZO XIMENA , RAMOS WILLY D. , VAN DAM ROBERT P. , DIEZ CARLOS E. , ABREU‐GROBOIS ALBERTO , MCMILLAN W. OWEN
Published: September 2010

We investigated the dispersal, recruitment and migratory behaviour of the hawksbill sea turtle (Eretmochelys imbricata), among different life‐history stages and demographic segments of the large hawksbill turtle aggregation at Mona Island, Puerto Rico. There were significant differences in both mitochondrial DNA (mtDNA) haplotype diversity and haplotype frequencies among the adult males, females and juveniles examined, but little evidence for temporal heterogeneity within these same groups sampled across years. Consistent with previous studies and the hypothesis of strong natal homing, there were striking mtDNA haplotype differences between nesting females on Mona Island and nesting females in other major Caribbean rookeries. Breeding males also showed strong, albeit weaker, genetic evidence of natal homing. Overall, Bayesian mixed‐stock analysis suggests that Mona Island was the natal rookery for 79% (65–94%) of males in the aggregation. In contrast, the Mona Island rookery accounted for only a small subset of the new juvenile recruits to the foraging grounds or in the population of older juvenile hawksbills turtles on Mona. Instead, both new recruits and the older juvenile hawksbill turtles on Mona more likely recruited from other Caribbean rookeries, suggesting that a mechanism besides natal homing must be influencing recruitment to feeding habitats. The difference in the apparent degree of natal homing behaviour among the different life‐history stages of hawksbill turtles at Mona Island underscores the complexity of the species’ life‐history dynamics and highlights the need for both local and regional conservation efforts.
Adapting to winter in wheat: a long‐term study follows parallel phenotypic and genetic changes in three experimental wheat populations
Authors: STRASBURG JARED L. , GROSS BRIANA L.
Published: September 2010

Drawing a direct connection between adaptive evolution at the phenotypic level and underlying genetic factors has long been a major goal of evolutionary biologists, but the genetic characterization of adaptive traits in natural populations is notoriously difficult. The study of evolution in experimental populations offers some help — initial conditions are known and changes can be tracked for extended periods under conditions more controlled than wild populations and more realistic than laboratory or greenhouse experiments. In this issue of Molecular Ecology, researchers studying experimental wheat populations over a 12‐year period have demonstrated evolution in a major adaptive trait, flowering time, and parallel changes in underlying genetic variation (Rhonéet al. 2008). Their work suggests that cis‐regulatory mutations at a single gene may explain most of the flowering time variation in these populations.
Tracking elusive timber rattlers with molecular genetics
Authors: SHINE RICHARD
Published: September 2010

Most biologists would agree that understanding the factors that influence gene flow among populations is important, because population connectivity is critical to effective conservation and management as well as to issues such as disease transmission and the degree of local adaptation. Nonetheless, our understanding of the mechanistic determinants of gene flow remains abysmally limited for many types of organisms. Predictably, some of the biggest gaps involve animals that are rare, secretive, and difficult to collect or handle — and thus, remain relatively unstudied for other traits as well. Large venomous snakes have long provided a classic example of such an under‐studied group, but the situation has changed dramatically over recent years. The study by Clark et al. in this issue builds upon our increasingly sophisticated understanding of snake behaviour, to interpret patterns of gene flow in the light of our emerging knowledge of snake behavioural ecology.
Morphology, sedimentology and palaeohydraulic significance of large gravel dunes, Altai Mountains, Siberia
Authors: CARLING P. A.
Published: September 2010

Coarse‐gravel bedforms which resulted from Pleistocene glacial outburst floods are identified as subaqueous dunes. Comparison of the morphology of these ‘fossil’ structures with modern dunes shows that the form of two‐dimensional (2‐D) transverse dunes and 3‐D cuspate and lunate dunes developed in coarse gravels is comparable with sand‐dune morphology within lesser‐scale geophysical flows. The similarity of the steepest gravel dunes with equilibrium dunes in sand indicates that grain size is not a major factor in constraining primary duneform.

Internal structure indicates that flow over 2‐D dunes was relatively uniform but over 3‐D bedforms flow was locally variable. Flow separation and complex streaming of flow occurred over the steepest 3‐D dunes. Cross‐beds are thin and few approach the angle of repose; consequently most dunes did not migrate primarily by avalanching but by stoss‐entrained gravel transported over the crests rolling‐down and depositing on the lee slopes.

Lee‐side sediments are often finer than the stoss‐slope sediments, which indicates the lee formed when flood power was waning. Some dunes were slightly planed‐down during falling stage because lee‐side cross‐beds tend to be steeper than the angle of the preserved lee slope. However, silt‐rich caps indicate that any height reduction was contemporary with the final deposition of foresets. Post‐flood modification has been negligible although the modern topography is subdued by loess deposits within the dune troughs.
Microspar development during early marine burial diagenesis: a comparison of Pliocene carbonates from the Bahamas with Silurian limestones from Gotland (Sweden)
Authors: MUNNECKE AXEL , WESTPHAL HILDEGARD , REIJMER JOHN J. G. , SAMTLEBEN CHRISTIAN
Published: September 2010

Comparison of ultrastructures in Pliocene periplatform carbonates from the Bahamas with Silurian limestones from Gotland (Sweden) reveals that despite the differences in primary sediment composition and age, they reflect a similar mechanism of lithification. In both sequences calcite microspar was formed as a primary cement at an early stage of marine burial diagenesis. Neither significant compression nor meteoric influence are necessary for the formation of calcite microspar. A model is proposed for the process of microsparitic cementation of fine‐grained aragonite needle muds comprising four stages: (1) unconsolidated, aragonite‐dominated carbonate mud; (2) precipitation of microspar that engulfs aragonite needles; (3) dissolution of aragonite, resulting in pitted surfaces of the microspar crystals; and (4) slight recrystallization. Our results contradict the widespread opinion that microspar necessarily is a product of secondary recrystallization of a previously lithified micrite.
Grain size distribution expressed as tanh‐functions
Authors: P°SSE TORE
Published: September 2010

The grain size distribution within a unimodal sediment can be described as a lognormal distribution when the distribution is formed by only one process. However, most sediments are formed by more than one process giving polymodal sediments. Polymodal sediments have to be described as the sum of several normal distributions, one for each process involved within the formation.

Grain size distributions are usually interpreted with the help of graphical methods. Interpretations of polymodal sediments require mathematical methods. In mathematical terms a unimodal sediment can be described as a tangential hyperbolic function (tanh) and a polymodal sediment can generally be described by the sum of two or three tanh‐functions. The tanh‐method is a tool for identifying and estimating the number of modes within a grain size distribution and helps interpret the processes involved within the formation of a deposit. The mathematical method can also be used to computerize sediment data, allowing storage with just a few numbers. Different samples can easily be compared and classified. Also, this method could be a valuable tool for calculations of various sediment parameters both in geotechnology and hydrogeology.
Late diagenetic calcitization of anhydrite from the Mississippian of Saskatchewan, western Canada
Authors: Kendall Alan C.
Published: September 2010

Mississippian nodular anhydrites beneath an unconformity in the subsurface of southern Saskatchewan are locally replaced by calcite, pyrite and celestite. Triassic clastics above the unconformity are green, rather than red, and a usually developed subunconformity alteration zone (where carbonates are dolomitized, and porosity is filled with anhydrite) is absent. The unconformity lacks karstic features (unlike in the USA), and probably formed in a hyperarid climate. Mississippian anhydrites near the unconformity are not preferentially dissolved, nor were they extensively hydrated. Anhydrite calcitization occurred only after the unconformity was shallowly buried by redbeds, and it probably involved sulphate‐reducing bacteria. Hydrogen sulphide, generated by bacteria, reduced redbed pigments. The replacement calcite contains pseudomorphs and relicts of anhydrite, and pseudomorphs of secondary gypsum. These indicate calcitization occurred only after original Mississippian gypsum was altered to anhydrite and this, in turn, was partially converted back to secondary gypsum beneath the unconformity. Replacement occurred concurrently with the formation elsewhere of the dolomitized zone beneath the unconformity. Sulphur isotopic ratios of replacement pyrite are depleted relative to Mississippian sulphate values, consistent with the activities of sulphate‐reducing bacteria. Carbon isotopic ratios of replacive calcites, however, do not support this interpretation, and are identical to those of Mississippian limestones. Simple replacement of sulphate by pore‐water bicarbonate (in equilibrium with host limestones) is unlikely because protons generated during the reaction should have created acidic conditions in which calcite would have dissolved. A full explanation of the calcitization remains elusive, but may involve replacement occurring in an active groundwater system and/or bacterial sulphate reduction occurring upstream of the site of calcitization.
Sequence stratigraphy of a low productivity carbonate platform succession: the Upper Permian Wegener Halvø Formation, Karstryggen Area, East Greenland
Authors: Stemmerik Lars
Published: September 2010

The carbonate platform of the Upper Permian Wegener Halvø Formation in the Karstryggen area of central East Greenland is an example of a carbonate system with low production rates (2–3 cm kyr–1) and differs from most other carbonate platforms by the lack of well‐developed highstand progradation. The platform consists of three depositional sequences that formed in response to Kazanian sea‐level cycles. Pinning point curves for the subaerial exposure surfaces separating the depositional sequences quantify the amplitude of the relative sea‐level fluctuations in the range of 70–140 m. The platform developed on the karstified surface of an older Permian carbonate platform with a topographic relief locally exceeding 70 m. The predepositional relief influenced deposition in all three sequences. Transgressive systems tracts are thin and commonly dominated by condensed siliciclastic deposits in off‐platform areas and palaeo‐lows. Over palaeotopographic highs they consist of aggrading cementstones. Highstand deposits are limited to palaeotopographic elevated areas and consist of cementstone build‐ups along the basin margin, and shallow subtidal to intertidal carbonates and evaporites in the platform area. Elsewhere, carbonate deposition took place during falling sea‐level, and thin laterally extensive units of shallow‐marine grainstones rest directly on top of deeper marine shales in the two first sequences, whereas thick prograding units of oolitic grainstones form the forced regressive systems tract of the uppermost sequence.
On the transition between 2D and 3D dunes
Authors: VENDITTI JEREMY G. , CHURCH MICHAEL , BENNETT SEAN J.
Published: September 2010

Sediment transport in sand‐bedded alluvial channels is strongly conditioned by bedforms, the planimetric morphology of which can be either two‐ or three‐dimensional. Experiments were undertaken to examine the processes that transform the bed configuration from two‐dimensional (2D) dunes to three‐dimensional (3D) dunes. A narrowly graded, 500 μm size sand was subjected to a 0·15 m deep, non‐varying mean flow ranging from 0·30 to 0·55 m sec−1 in a 1 m wide flume. Changes in the planimetric configuration of the bed were monitored using a high‐resolution video camera that produced a series of 10 sec time‐lapsed digital images. Image analysis was used to define a critical value of the non‐dimensional span (sinuosity) of the bedform crestlines that divides 2D forms from 3D forms. Significant variation in the non‐dimensional span is observed that cannot be linked to properties of the flow or bedforms and thus appears random. Images also reveal that, once 2D bedforms are established, minor, transient excesses or deficiencies of sand are passed from one bedform to another. The bedform field appears capable of absorbing a small number of such defects but, as the number grows with time, the resulting morphological perturbations produce a transition in bed state to 3D forms that continue to evolve, but are pattern‐stable. The 3D pattern is maintained by the constant rearrangement of crestlines through lobe extension and starving downstream bedforms of sediment, which leads to bifurcation. The experiments demonstrate that 2D bedforms are not stable in this calibre sand and call into question the reliability of bedform phase diagrams that use crestline shape as a discriminator.
Late Pliocene to Holocene platform evolution in northern Belize, and comparison with coeval deposits in southern Belize and the Bahamas
Authors: MAZZULLO S.J.
Published: September 2010

Lithostratigraphy, depositional facies architecture, and diagenesis of upper Pliocene to Holocene carbonates in northern Belize are evaluated based on a ca 290 m, continuous section of samples from a well drilled on Ambergris Caye that can be linked directly to outcrops of Pleistocene limestone, and of overlying Holocene sediments. Upper Pliocene outer‐ramp deposits are overlain unconformably by Pleistocene and Holocene reef‐rimmed platforms devoid of lowstand siliciclastics. Tectonism controlled the location of the oldest Pleistocene platform margin and coralgal barrier reef, and periodically affected deposition in the Holocene. A shallow, flat‐topped, mostly aggradational platform was maintained in the Holocene by alternating periods of highstand barrier‐reef growth and lowstand karstification, differential subsidence, and the low magnitude of accommodation space increases during highstands. Facies in Pleistocene rocks to the lee of the barrier reef include: (i) outer‐shelf coralgal sands with scattered coral patch reefs; (ii) a shoal–water transition zone comprising nearshore skeletal and oolitic sands amidst scattered islands and tidal flats; and (iii) micritic inner‐shelf deposits. Four glacio‐eustatically forced sequences are recognized in the Pleistocene section, and component subtidal cycles probably include forced cycles and autocycles. Excluding oolites, Holocene facies are similar to those in the Pleistocene and include mud‐mounds, foraminiferal sand shoals in the inner shelf, and within the interiors of Ambergris and surrounding cayes, mangrove swamps, shallow lagoons, and tidal and sea‐marginal flats. Meteoric diagenesis of Pliocene and Pleistocene rocks is indicated by variable degrees of mineralogic stabilization, generally depleted whole‐rock δ18O and δ13C values, and meniscus and whisker‐crystal cements. Differences in the mineralogy and geochemistry of the Pliocene and Pleistocene rocks are attributed to variable extent of meteoric alteration. Dolomitization in the Pliocene carbonates may have begun syndepositionally and continued into the marine shallow‐burial environment. Positive dolomite δ18O and δ13C values suggest precipitation from circulating, near‐normal marine fluids that probably were modified somewhat by methanogenesis. Sedimentologic and diagenetic attributes of the Pliocene–Pleistocene rocks in the study area are similar to those in the Bahamas with which they share a common history of sea‐level fluctuations and climate change.
Sequence stratigraphy of a carbonate‐evaporite succession (Zechstein 1, Hessian Basin, Germany)
Authors: BECKER FRANK , BECHSTÄDT THILO
Published: September 2010

The evaporitic Hessian Zechstein Basin is a sub‐basin of the Southern Zechstein Basin, situated at its southern margin. Twelve facies groups were identified in the Zechstein Limestone and Lower Werra Anhydrite in order to better understand the sequence‐stratigraphic evolution of this sub‐basin, which contains economically important potassium salts. Four different paleogeographic depositional areas were recognized based on the regional distribution of facies. Siliciclastic‐carbonate, carbonate, carbonate‐evaporite and evaporite shallowing‐upward successions are developed. These allow the establishment of parasequences and sequences, as well as correlation throughout the Hessian Basin and into the Southern Zechstein Basin. Two depositional sequences are distinguished, Zechstein sequence 1 and Zechstein sequence 2. The former comprises the succession from the Variscan basement up to the lowermost part of the Werra Anhydrite, including the Kupferschiefer as part of the transgressive systems tract. The highstand systems tract is defined by the Zechstein Limestone, in which two parasequences are developed. In large parts of the Hessian Basin, Zechstein sequence 1 is capped by a karstic, subaerial exposure surface, interpreted as recording a type‐1 sequence boundary that formed during a distinct brine level fall. Low‐lying central areas (Central Hessian Sub‐basin, Werra Sub‐basin), however, were not exposed and show a correlative conformity. Topography was minimal at the end of sequence 1. Widely developed perilittoral, sabkha and salina shallowing‐upward successions indicate a renewed rise of brine level (interpreted as a transgressive systems tract), because of inflow of preconcentrated brines from the Southern Zechstein Basin to the north. This marks the initiation of Zechstein sequence 2, which comprises most of the Lower Werra Anhydrite. In the Central Hessian Sub‐basin, situated proximal to the brine inflow and on the ridges within the Hessian Basin, physico‐chemical conditions were well suited for sulphate precipitation to form a thick cyclic succession. It consists of four parasequences that completely filled the increased accommodation space. In contrast, only minor sulphate accumulation occurred in the Werra Sub‐basin, situated further southwards and distal to the inflow. As a result of substantially different sulphate precipitation rates during increased accommodation, water depth in the region became more variable. The Werra Sub‐basin, characterized by very low sedimentation rates, became increasingly deeper through time, trapping dense halite brines and precipitating rock salt deposits (Werra Halite). This ‘self‐organization’ model for an evaporitic basin, in which depositional relief evolves with sedimentation and relief is filled by evaporite thereafter, contradicts earlier interpretations, that call upon the existence of a tectonic depression in the Werra area, which controlled sedimentation from the beginning of the Zechstein.
Prediction of joint herbicide action by biomass and chlorophyll a fluorescence
Authors: SØBYE K W , STREIBIG J C , CEDERGREEN N
Published: September 2010

Søbye KW, Streibig JC & Cedergreen N (2011). Prediction of joint herbicide action by biomass and chlorophyll a fluorescence. Weed Research 51, 23–32.

The joint effect of binary mixtures of the 4‐hydroxyphenylpyruvate dioxygenase inhibitor isoxaflutole with glyphosate and metribuzin on Beta vulgaris was analysed with dose–response curves. The hypothesis was to test divergence from the Additive Dose Model (ADM), as a reference model. The Fvj parameter [(Fm − Fj)/Fm] and two new parameters, based on the slope at the J and the I step of the Kautsky curve, measured 2 days after spraying, and biomass 3 weeks after spraying, were used as responses. Synergistic effects of mixtures of isoxaflutole with numerous herbicides have been patented and were thus the working hypothesis. The shapes of isoboles, a contour plot of all mixtures of two herbicides that give the same effect, was variable, but the results of the mixtures with isoxaflutole, however, did not show statistically significant departure from the ADM. This applies to all endpoints: biomass and the Kautsky curve parameters, Fvj, Slope‐I and Slope‐J. The variability of isobole shapes is discussed, as is the use of statistical assessment of isobole parameters. The parameters from the Kautsky curves after 48 h predicted the isobole just as well as biomass after 20 days and could be used as a rapid scan for the divergence of joint action of mixtures from the ADM, long before visible symptoms develop.
Seventy‐eight novel HLA class I and II alleles identified during routine registry typing in 2008 and 2009
Authors: Lazaro A. M. , Xiao Y. , Masaberg C. , Tu B. , Ng J. , Hurley C. K. , Posch P. E.
Published: September 2010

Seventy‐eight novel human leukocyte antigen (HLA) class I and class II alleles are described: 19 HLA‐A alleles, 30 HLA‐C alleles, 21 HLA‐B alleles, 7 HLA‐DRB1 alleles and 1 HLA‐DPB1 allele. Eight (∼10%) of the novel alleles were found in more than one individual and may be more common in the population. Sixty‐two (∼80%) of the 78 novel alleles are single nucleotide substitution variants when compared with their most homologous allele. Twelve of these single nucleotide variants are silent substitutions and one creates a null allele (C*08:26N). One of the novel HLA‐C alleles, C*03:58, is a hybrid that likely resulted from an intra‐locus recombination. The remaining novel alleles differ from their most similar allele by two to seven nucleotide substitutions. Four of the novel HLA‐C alleles encode amino acid changes at codons 41, 42, 55 or 200 which have not previously been reported to be polymorphic. Some of the new alleles encode novel codons and unique amino acid changes at polymorphic positions in the HLA‐A (codons 55 and 120), HLA‐C (codons 151, 153 and 176), HLA‐B (codons 31 and 84) and HLA‐DRB1 (codon 47) loci.
Structural basis for the light regulation of chloroplast NADP malate dehydrogenase
Authors: Ashton Anthony R. , Trevanion Stephen J. , Carr Paul D. , Verger Denis , Ollis David L.
Published: September 2010

The activity of chloroplast NADP‐malate dehydrogenase (NADP‐MDH; EC 1.1.1.82) in both C3 and C4 plants is regulated by light intensity. In darkness, the activity of the enzyme can be less than 1% of the maximal activity found at high light intensities. The extent of activation in the light is dynamic, responding rapidly to changes in light intensity and adapting to changes in photosynthetic rate. Enzyme activation is caused by thioredoxin‐catalyzed reduction of two regulatory disulfide bonds, while inactivation is accomplished by thioredoxin‐catalyzed re‐oxidation. In the case of NADP‐MDH, the coenzyme substrates NADP+ and NADPH modify the rate of this interconversion and seem to be important to the extent of activation in vivo. The recent determination of the X‐ray structure of the oxidized, dark form of NADP‐MDH from the C4 plants Flaveria bidentis and Sorghum shows how oxidation of a disulfide bond can inactivate the enzyme. This review discusses the various structural features of NADP‐MDH that seem to be responsible for the regulatory properties of the enzyme and emphasizes that large changes of activity can be accomplished by multiple, small, reinforcing changes rather than a single large change in a signal molecule concentration.
Lead disturbs microtubule organization in the root meristem of Zea mays
Authors: Eun Soon‐Ok , Shik Youn Hwa , Lee Youngsook
Published: September 2010

Lead is an environmental pollutant that interferes with plant growth. Unfortunately, the mechanisms of lead toxicity in plants are still poorly understood. In this study, we have investigated both the deposition sites and sources of cellular toxicity of lead in maize seedlings (Zea mays L. cv. Golden Cross Bantam). Using atomic absorption spectroscopy and X‐ray fluorescence microprobing, we show that lead accumulation is highest in the root meristem, and that the accumulation occurs both in the apoplast and symplast. Since cells are dividing vigorously in this region and because microtubules play an important role in cell division, we have further examined the effects of lead on microtubules in the root meristem. Lead treatment perturbed the alignment of microtubules in a concentration‐dependent manner beginning at 10 μM. Microtubules of different regions of the root meristem and in different stages of the cell cycle showed differential susceptibility to lead. These effects do not appear to be general phenomena common to toxic metals, since aluminum and copper, at concentrations that decreased root growth to a comparable level, did not have the same detrimental effects on microtubules. Based on these results, we suggest that the damage to microtubules is partly responsible for lead‐associated toxicity in plants.
Rate and duration of grain filling in relation to flag leaf senescence and grain yield in spring wheat (Triticum aestivum) exposed to different concentrations of ozone
Authors: Gelang Johanna , Pleijel Håkan , Sild Ebe , Danielsson Helena , Younis Suhaila , Selldén Gun
Published: September 2010

Effects of different concentrations of ozone on grain filling, flag leaf senescence and final grain yield in field‐grown spring wheat (Triticum aestivum L. cv. Dragon) were studied using open‐top chambers. The hypothesis tested was that an ozone‐induced reduction in grain yield is mainly related to an enhanced senescence and a shortening of the grain‐filling period. The plants were exposed to filtered air (F), non‐filtered air without extra ozone (NF) or non‐filtered air with 3 different levels of ozone added (NF1+, NF2+ and NF3+). The mean daytime (08.00–20.00 h) ozone concentrations during the exposure period (31 days) were 7, 20, 34, 48 and 62 nmol mol−1 in F, NF, NF1+, NF2+ and NF3+, respectively. The corresponding ozone doses, expressed as the accumulated exposure over a concentration threshold of 40 nmol mol−1 (AOT40), were 0, 12, 1 989, 5 881 and 10 375 nmol mol−1 h, respectively, and 884, 2 594, 4 557, 6 188 and 7 900 μmol m−2, respectively, expressed as the calculated cumulative flag leaf ozone flux (CFO30). The flag leaves senesced earlier and the grain‐filling duration was significantly shorter at higher ozone exposure compared to F (−5, −13 and −18% in NF1+, NF2+ and NF3+, respectively). The relative grain‐filling rate did not differ between the treatments. The 1000‐grain weights were 10, 28 and 37% lower, and the grain yields were 15, 29 and 46% lower than F in NF1+, NF2+ and NF3+, respectively. Ozone exposure had no significant effect on the number of grains per unit ground area or on straw yield, but significantly reduced the harvest index and increased the grain protein concentration in NF2+ and NF3+ compared to F. The grain yield was negatively correlated with the ozone dose, expressed either as AOT40 or as CFO3 with or without an ozone flux threshold. The 1000‐grain weight was positively correlated with the grain‐filling duration (R2=0.998), which in turn was positively correlated with the leaf area duration (R2=0.989).
Proline level is partly under the control of abscisic acid in canola leaf discs during recovery from hyper‐osmotic stress
Authors: Trotel‐Aziz Patricia , Niogret Marie‐Françoise , Larher François
Published: September 2010

The relationships between the changes induced in abscisic acid (ABA) and proline contents were investigated in canola (Brassica napus L.) leaf discs (CLDs) subjected to sequential hyper‐ and hypo‐osmotic treatments. Changes in ABA content were found to precede that of proline, suggesting that ABA could exert regulatory effects on both osmo‐induced proline accumulation and its subsequent mobilization during recovery. When exogenously supplied in the light during recovery, ABA caused inhibition of the apparent rate of proline mobilization with an I50 of about 20 μM. Under dark conditions, the ABA effect was not observed. This is in accordance with the fact that this effect could be suppressed in the light while using photosynthesis inhibitors. The ABA effect was partly restored under dark conditions when the CLDs were supplied with NADPH at high concentration. Under both conditions, ABA exerted its effect when supplied together with cycloheximide, suggesting that it does not rely on protein synthesis. When turgid CLDs, which heavily absorbed exogenously supplied l‐proline, were incubated in the light on the reference medium with ABA, proline mobilization was also restricted, provided ABA was supplied during the period of proline uptake. Surprisingly, in CLDs that had recovered their full turgor after application of successive hyper‐ and hypo‐osmotic treatments, application of ABA led to a very high accumulation of proline. In contrast, in freshly cut turgid CLDs incubated in presence of ABA, the basic proline level was only weakly enhanced. Thus, the apparent inhibitory effect of ABA on proline mobilization could be mediated through both an activation of biosynthesis and an inhibition of catabolism of this amino acid via light‐dependent processes that remain to be elucidated.
Isolation of an elicitor‐stimulated 5‐epi‐aristolochene synthase gene (gPEAS1) from chili pepper (Capsicum annuum)
Authors: Zavala‐Páramo Guadalupe , Chávez‐Moctezuma Martha P. , García‐Pineda Ernesto , Yin Shaoui , Chappell Joseph , Lozoya‐Gloria Edmundo
Published: September 2010

Phytoalexins play an important role in the inducible defense responses of plants against diseases caused by fungi. Some enzymes, involved in the respective biosynthetic pathways, catalyze key steps. Farnesyl pyrophosphate (FPP) is a key intermediate in the biosynthesis of terpenes. It may be converted into several cyclic and some acyclic sesquiterpenic derivatives, sterol precursors, or to geranylgeranyl pyrophosphate according to the requirements of the plant cells. Specific cyclization reactions of FPP are catalyzed by particular sesquiterpene cyclases. The 5‐epi‐aristolochene synthase (EAS) enzyme of tobacco (Nicotiana tabacum) and pepper (Capsicum annuum) produce the 5‐epi‐aristolochene, which is the immediate precursor of the bicyclic phytoalexin capsidiol. Oligonucleotides homologous to 3′‐end specific regions of tobacco and Hyoscyamus muticus inducible sesquiterpene cyclase genes were used with the system for rapid amplification of cDNA ends (3′‐RACE) technique to prepare pepper EAS‐cDNA fragments (PEAS‐cDNA). Three specific PEAS‐cDNAs were isolated (PEAS1, PEAS18, and PEAS55). Northern blots of total RNA samples from pepper plant tissues challenged with cellulase or Phytophthora capsici showed different expression levels of the respective transcripts. PEAS1 was used to identify the corresponding elicitor‐stimulated gene (gPEAS1). The nucleotide sequence of the proposed gPEAS1 promoter showed putative stimuli‐ and tissue‐specific responsive elements. A pepper 5‐epi‐aristolochene synthase gene family of 5–8 members was demonstrated by Southern blot.
Relative control potential of abscisic acid, carbon dioxide and light in responses ofPhaseolus vulgarisstomata
Authors: Paterson Neil W. , Weyers Jonathan D. B. , Herdman Lindsey
Published: September 2010

We outline a theoretical framework for comparing the relative effectiveness of hormonal and other factors in the control of physiological responses. This involves determining a ‘baseline’ set of conditions, then adjusting each factor in turn with the others held constant. The initial rate of response to each change in condition is estimated and compared among factors to arrive at a quantitative indication of control potential under the specified baseline conditions – the control coefficient. The suitability of the stomatal response as a model system for such studies is discussed. A portable infra‐red gas analyser was used to investigate the control potential of abscisic acid (ABA), CO2and light – measured as photosynthetic photon flux density (PPFD) – over responses ofPhaseolus vulgarisL. stomata at baseline conditions appropriate to an unstressed plant under moderate light conditions. The ranking of control coefficients observed under these conditions was light>CO2>ABA. The control coefficients of CO2and ABA were 0.28 and 0.11 times that of light, respectively. These results are discussed in relation to the sensitivity of the plant material and the experimental conditions. Implications for a hormonal role for ABA in the control of stomatal movements are considered. We conclude that this method can provide valuable information concerning the relative control potential of hormonal and other influences in the context of differences in baseline conditions and in relation to changes in sensitivity of plant material.
Effects of water stress on major photosystem II gene expression and protein metabolism in barley leaves
Authors: Yuan Shu , Liu Wen‐Juan , Zhang Nian‐Hui , Wang Ma‐Bin , Liang Hou‐Guo , Hui Lin Hong‐
Published: September 2010

Although it has long been recognized that water deficit in plants reduces photosystem (PS) II mRNAs and proteins, the detailed mechanisms behind this have not been thoroughly elucidated. In the present study, effects of water stress in barley leaves on degradation of major PSII mRNA and dissociation and migration of PSII proteins were investigated. The results indicated that (1) the steady‐state levels of major PSII mRNAs and proteins declined with increasing water stress, as a consequence of increased degradation; under severe water stress, the half‐lives of D1 and D2 proteins decreased from 12–14 h to 7–8 h and the half‐lives of psbA and psbD mRNA decreased from above 16 to 6–10 h; (2) monomerization of PSII were increased during water stress. Severe water stress accelerated turnover of PSII and inhibited PSII activities.
Contribution of inorganic components to osmotic adjustment and leaf folding for drought tolerance in pearl millet
Authors: Kusaka Masayuki , Ohta Masaru , Fujimura Tatsuhito
Published: September 2010

Pearl millet, Pennisetum glaucum, is capable of adapting to severely dry environmental conditions. In order to elucidate the mechanism of adaptation to highly dehydrated conditions, we selected both tolerant (IP8210) and susceptible (IP8949) accessions from a total of 15 pearl millet accessions and characterized their morphological and physiological responses to severe drought stress. When these selected accessions were stressed with a severe drought treatment, the leaves of IP8210 exhibited upright folding, a response that effectively reduces the evaporative surface area of the canopy. On the contrary, the leaves of IP8949 exhibited wilting and did not appear to adapt to the drought stress. In comparison with IP8949, the capacity of osmotic adjustment (OA) was greater in both younger leaves and stems of IP8210, while their decrease in relative water content was different. IP8210 accumulated higher concentrations of NO3– than IP8949 in response to drought stress. In addition to inorganic solutes, several organic components such as sucrose, glucose, quaternary ammonium compounds, and amino acids including proline were also accumulated. IP8210 tended to accumulate more amino acids, typically due to the accumulation of asparagine and proline, while IP8949 accumulated more soluble sugars. While it is possible that K+ and NO3– were the major components contributing to osmotic regulations, sugars and amino acids might also function as a cytoprotectant, in addition to their role as osmoprotectants. Collectively, these results demonstrate that the morphological adaptation of leaf folding, OA in both the younger leaves and the stem, and the accumulation of NO3– and amino acids during earlier stress period contribute to superior drought tolerance that was exhibited in IP8210 of pearl millet.
Ecophysiological and morphological parameters related to survival in grass species exposed to an extreme climatic event
Authors: Milbau Ann , Scheerlinck Liesbeth , Reheul Dirk , De Cauwer Benny , Nijs Ivan
Published: September 2010

An experiment was performed to elucidate interspecific differences in survival time of grass species subjected to an extreme climatic event. We exposed eight grass species to a simulated heat wave in the field (‘free air’ temperature increase at 11°C above ambient) combined with drought. We determined whether interspecific differences in survival time were related to the responses of the species to the imposed stress or could be explained by their ecophysiological or morphological characteristics in unstressed conditions. Surprisingly, there was no effect of specific leaf area, but species with a higher total leaf area survived longer. This may arise from a greater water reserve in the plant as a whole, which could delay the desiccation of the meristem, or from reduced evaporation due to a higher leaf area index. Species in which the decrease in light‐saturated stomatal conductance (gs) and photosynthetic CO2 uptake rate (Amax) was strongly related to the decrease in soil water availability (measured as soil relative water content and stress duration) survived longer than species in which gs and Amax likewise declined but responded more to daily fluctuations in irradiance, temperature, and vapor pressure deficit during the heat wave. We, therefore, hypothesize that interspecific differences in stress survival time might be related to the extent to which stomata react to changes in soil water conditions relatively to changes in other environmental and physiological factors. The results suggest that resistance to extremes is governed by other mechanisms than resistance to moderate drought.
Transport of macromolecules through plasmodesmata and the phloem
Authors: Chen Xiong‐Yan , Kim Jae‐Yean
Published: September 2010

Cell‐to‐cell communication is a pivotal process in the determination of cell fate during development and physiological adaptation in response to environmental stimuli. The intercellular trafficking of proteins and RNAs has emerged as a novel mechanism of cell‐to‐cell signaling in plants. As a strategy for efficient intercellular communication, plants have evolved plant‐specific symplasmic communication networks via plasmodesmata (PD) and the phloem. PD are symplasmic channels connecting the cytoplasm of neighboring cells and are responsible for the local exchange of metabolites and signaling molecules. The phloem is the sieve‐tube system that allows rapid, long‐distance translocation of molecules. Together, PD and phloem conduits have been shown to allow the transport of proteins and RNAs in non‐selective or/and selective modes. This review describes the current understanding of macromolecule trafficking through PD and the phloem.
Metabolomics integrated with transcriptomics: assessing systems response to sulfur‐deficiency stress
Authors: Hoefgen Rainer , Nikiforova Victoria J.
Published: September 2010

Sulfur‐containing amino acids, cysteine and methionine synthesized in plants are essential for human and animal nutrition. That is why understanding of how inorganic sulfur is taken up by plants and built into the organic molecules in the process of sulfur assimilation is important. As complex biological systems, plants subsist as integrated molecular, organelle, cell, tissue and organ entities, being in permanent synergistic coordination. The process of sulfur uptake and assimilation is an integral part of this dense network of influences, its reconstruction may help in manipulating the bioproduction of organic sulfur‐containing compounds. New high‐throughput technologies allow the systems’ view on the coordination of complex processes in living organisms. Among them, transcriptomics and metabolomics studies were applied to Arabidopsis plants subjected to sulfur‐deficiency stress. From the integrated analysis of the obtained data, the mosaic picture of distinct sulfur stress response events and processes are starting to be assembled into the whole systems’ network of sulfur assimilation. At the time trajectory of sulfur stress response, two system states can be distinguished. The first state of short‐term responses is characterized by the development of enhanced lateral roots exploring the space in search for the lacking nutrient. When this physiological reaction cannot be accomplished by bringing the system back to the initial state of sulfur sufficiency, a new program is toggled aiming at saving the organismal resources for vital seed production. Here, we describe the biological reasoning in these two system states and the process of state transition between them.
Transitory interruption of recommended storage conditions does not cause significant changes in in vitro parameters of leucocyte‐depleted red blood cells
Authors: Weiss D. R. , Fortenbacher S. , Ringwald J. , Strasser E. F. , Zimmermann R. , Eckstein R.
Published: September 2010

Background and Objectives  Conventional quality control studies of the shelf life of RBC units do not consider cold chain interruptions that occur during cross‐matching or between the release of RBCs from the blood bank and their return from the ward. These interruptions may, however, lead to a considerable loss of quality. On the other hand, differences in the quality of RBCs may derive from the different manufacturing processes employed in various blood centres.

Materials and Methods  One day after the expiry date of the RBC unit, we analysed complete blood count, blood gas, potassium, LDH, hydroxybutyrate dehydrogenase, glucose, lactate, total and free haemoglobin (Hb) and ATP and compared the results with regard to the frequency of storage interruptions and to two manufacturers of these RBCs.

Results  We could not find any correlations between the frequency of interruptions (0–11) and these parameters in any of the data sets. However, we found significant differences when comparing the two suppliers. RBCs of manufacturer A (‘A’, inline filtration of whole blood) contained 25% more Hb than those of manufacturer B (‘B’, inline filtration after buffy coat reduction). Sixteen percentage of ‘A’‐RBC, but none of ‘B’‐RBC, exceeded a haemolysis of 0·8%.

Conclusions  Transitory interruptions of cold chain do not measurably impair the quality of RBCs. The effect on storage of RBCs in the blood bank is not as significant a factor as the differences that exist between RBC manufacturing procedures.
Influence of late irradiation on the in vitro RBC storage variables of leucoreduced RBCs in SAGM additive solution
Authors: Zimmermann R. , Schoetz A. M. , Frisch A. , Hauck B. , Weiss D. , Strobel J. , Eckstein R.
Published: September 2010

Background  There exists only few data on in vitro and in vivo effects of gamma irradiation of leucoreduced red blood cells (RBCs). Reported studies reflect the effects of early irradiation and subsequent storage. The effects of irradiation on RBCs shortly before the end of their shelf‐life have not been examined.

Study Design and Methods  We studied 160 RBC units that were stored in the additive solution saline–adenine–glucose–mannitol and leucoreduced on the collection day. Forty components were irradiated on day +14 with 30 Gy, 40 on day +28, 40 on day +35, and 40 served as nonirradiated controls. In vitro evaluation of all units was performed on days +3, +7, +14, +21, +28, +35, and +42 from the collection day.

Results  Gamma irradiation induced leakage of potassium ions and lactate dehydrogenase and enhanced in vitro haemolysis rate in the irradiated components, which started to increase faster than that of nonirradiated RBCs from the day of irradiation, i.e. from day +14 in units that were irradiated on day +14, from day +28 in units that were irradiated on day +28, and from day +35 in units that were irradiated on day +35.

Conclusions  This study presents data on the in vitro quality of leucoreduced RBCs that have been irradiated on days +14, +28, or +35 after collection. Our findings support the proposal that the current limitation of the age of RBCs on the day of gamma irradiation may be replaced by staged limitations depending on the time of irradiation.
Spatial pattern of coastal fish assemblages in different habitats in North‐western Mediterranean
Authors: La Mesa Gabriele , Molinari Andrea , Gambaccini Silvia , Tunesi Leonardo
Published: September 2010

Variability of fish assemblages across habitat structures can depend on spatial scales. A hierarchical sampling design was used to assess the spatial variability of temperate fish assemblages in different habitats and at multiple scales. Underwater visual censuses were carried out along the coasts of Elba Island (NW Mediterranean) on Posidonia oceanica beds, rocky algal reefs and sandy habitat at three spatial scales, namely tens of metres (individual replicates), hundreds of metres (sites) and tens of kilometres (locations). At the assemblage level, there was a clear relationship between fish and habitat type and the observed habitat‐related differences were largely dependent on species identity. Fish assemblages on P. oceanica beds and rocky reefs shared a high number of species, whereas overlap with sandy assemblages was negligible. Multivariate analyses revealed significant differences in fish assemblages among habitats, although there was also a significant habitat × site interaction. These differences relied mainly upon assemblage composition and species richness. Assemblages on rocky reefs and P. oceanica meadows usually harboured a higher number of species and individuals compared with sandy assemblages. Nevertheless, the patterns of habitat‐related differences in species richness and, especially, in the total number of fish, changed significantly from site to site. Eight species showed significant differences over habitats, but they were not consistent due to the interaction of habitat with site. Predictability of fish at both assemblage and population levels decreased with the scale of observation, and the spatial pattern of fish observed at the smallest scale was likely dependent on factors other than habitat type.
Cerebral vasculitis in chronic mucocutaneous candidiasis: Autopsy case report
Authors: Nagashima Toshiko , Miyanoshita Akihiko , Sakiyama Yukio , Ozaki Yoshimaru , Stan Alexandru C. , Nagashima Kazuo
Published: September 2010

An autopsy case of chronic mucocutaneous candidiasis (CMCC) is reported here, in which cerebral vasculitis developed in the final stage. A 32‐year‐old man who had suffered from superficial candidial infection since his childhood was diagnosed as having CMCC. During the past 7 years the patient had developed various associated disorders including insulin‐dependent diabetes mellitus (IDDM), common variable immunodeficiency (CVID), candidial esophagitis, multiple digestive tract ulcers and pyothorax. In 1998, at the age of 32, he developed convulsions that were accompanied by impairment of consciousness, and which were temporarily treated with steroid pulsed‐medication. Epileptic status associated with widespread cerebral infarctions occurred subsequently, however, and the patient died of sepsis 2 months later. At autopsy, multiple cerebral infarctions and arterial thrombosis were evident. These were histologically proven to be primary vasculitis which was confined solely to the brain, and this was verified by general pathological examination. Thus, some as yet unknown cerebrovascular factors might be involved in the onset of an autoimmune‐related vasculitis in patients with a longstanding immunodeficiency state such as CMCC.