bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reproductive ecology of the freshwater red alga Batrachospermum delicatulum (Batrachospermales, Rhodophyta) in three tropical streams
Authors: Necchi Orlando , Vis Morgan L. 
Published: October 2005

SUMMARY Batrachospermum delicatulum specimens from three stream segments were analyzed from a tropical region in south‐ eastern Brazil (20°18′– 20°49′S, 49°13′– 49°46′W). Physical and chemical parameters and the spatial placement of thalli were investigated along with the reproductive characteristics of the gametophytic phase. Sequence data of the cox 2‐ 3 spacer region was also utilized to evaluate genetic variation in individuals within and among stream segments. Gametophyte occurred under relatively diverse environmental conditions, whereas thalli abundance was weakly or not correlated to environmental variables within the stream segments. All specimens examined were dioecious. The ratio of male/female plants was relatively low (0.5 to 1.3) and male plants tended to occur as clumps (two or three plants together). High reproductive success was observed, as indicated by the occurrence of 100% fertilized (carposporophytic) female plants. This is similar to previous reports for this and other dioecious species, which is remarkable considering the relatively low proportion of male/female plants. Results support the two hypotheses to explain the high reproductive success in dioecious species. The occurrence of male plants in clumps was evidence for a strict spatial relationship (i.e. male plants located in upstream position of female plants in order to release spermatia, which would be carried by eddies through female plants). In contrast, the occurrence of male and female plants adjacent to each other allowed outcrossing among neighboring plants with intermingled male and female branches, which seemed more applicable to some situations (low turbulence habitats). The cox 2‐ 3 spacer region from the 18 individuals sequenced was 376 bp and the DNA sequence was identical with no base pair substitutions. Likewise, a previous study of another Batrachospermum species showed that the same haplotypes were present in all stream segments from the same drainage basin, even though the stream segments were a considerable distance apart. Short distance dispersal either by small birds or waterway connectivity might explain these findings.
Accounting for uncertainty in marine reserve design
Authors: Halpern Benjamin S. , Regan Helen M. , Possingham Hugh P. , McCarthy Michael A. 
Published: October 2005

AbstractEcosystems and the species and communities within them are highly complex systems that defy predictions with any degree of certainty. Managing and conserving these systems in the face of uncertainty remains a daunting challenge, particularly with respect to developing networks of marine reserves. Here we review several modelling frameworks that explicitly acknowledge and incorporate uncertainty, and then use these methods to evaluate reserve spacing rules given increasing levels of uncertainty about larval dispersal distances. Our approach finds similar spacing rules as have been proposed elsewhere – roughly 20–200 km – but highlights several advantages provided by uncertainty modelling over more traditional approaches to developing these estimates. In particular, we argue that uncertainty modelling can allow for (1) an evaluation of the risk associated with any decision based on the assumed uncertainty; (2) a method for quantifying the costs and benefits of reducing uncertainty; and (3) a useful tool for communicating to stakeholders the challenges in managing highly uncertain systems. We also argue that incorporating rather than avoiding uncertainty will increase the chances of successfully achieving conservation and management goals.
Tracking carbon from the atmosphere to the rhizosphere
Authors: Olsson Pål A. , Johnson Nancy C. 
Published: October 2005

AbstractTurnover rates of arbuscular mycorrhizal (AM) fungi may influence storage of soil organic carbon (SOC). We examined the longevity of AM hyphae in monoxenic cultures; and we also used 13C incorporation into signature fatty acids to study C dynamics in a mycorrhizal symbiosis involving Glomus intraradices and Plantago lanceolata. 13C enrichment of signature fatty acids showed rapid transfer of plant assimilates to AM fungi and a gradual release of C from roots to rhizosphere bacteria, but at a much slower rate. Furthermore, most C assimilated by AM fungi remained 32 days after labelling. These findings indicate that 13C labelled fatty acids can be used to track C flux from the atmosphere to the rhizosphere and that retention of C in AM fungal mycelium may contribute significantly to SOC.
Additive and interactive effects of plant genotypic diversity on arthropod communities and plant fitness
Authors: Johnson Marc T. J. , Lajeunesse Marc J. , Agrawal Anurag A. 
Published: October 2005

AbstractRecent research suggests that genetic diversity in plant populations can shape the diversity and abundance of consumer communities. We tested this hypothesis in a field experiment by manipulating patches of Evening Primrose (Oenothera biennis) to contain one, four or eight plant genotypes. We then surveyed 92 species of naturally colonizing arthropods. Genetically diverse plant patches had 18% more arthropod species, and a greater abundance of omnivorous and predacious arthropods, but not herbivores, compared with monocultures. The effects of genotypic diversity on arthropod communities were due to a combination of interactive and additive effects among genotypes within genetically diverse patches. Greater genetic diversity also led to a selective feedback, as mean genotype fitness was 27% higher in diverse patches than in monocultures. A comparison between our results and the literature reveals that genetic diversity and species diversity can have similar qualitative and quantitative effects on arthropod communities. Our findings also illustrate the benefit of preserving genetic variation to conserve species diversity and interactions within multitrophic communities.
Transfer of endophyte‐origin defensive alkaloids from a grass to a hemiparasitic plant
Authors: Lehtonen Päivi , Helander Marjo , Wink Michael , Sporer Frank , Saikkonen Kari 
Published: October 2005

AbstractPlants growing in natural environments experience myriad interactions with a diverse assemblage of pathogens, parasites and mutualists. Many of these interactions involve symbiotic bacteria and fungi, but they also include macroparasitic plants. In this study, we investigated the interactions among a host grass (Lolium pratense, ex., Festuca pratensis), its symbiotic endophytic fungus (Neotyphodium uncinatum), a root hemiparasitic plant (Rhinanthus serotinus) of the host grass and a generalist herbivore (aphid Aulacorthum solani) of the hemiparasite. We demonstrate that the hemiparasitic plant acquires defending mycotoxins produced by the endophytic fungus living within their shared host grass. The uptake of defensive mycotoxins from the endophyte‐infected host grass enhances the resistance of the hemiparasitic plant to the generalist aphid herbivore. Endophyte infection increases the performance of the hemiparasitic plant, but reduces the growth of the host grass. In other words, the mutualistic endophytic fungus becomes parasitic in the presence of the hemiparasitic plant. Our results suggest that the outcomes of grass–endophyte interactions are conditional on the complexity of community‐level interactions; thus, the outcome of multispecies interactions may not be predictable from pair‐wise combinations of species.
Effects of Suction on the Nonstationary Lower Branch Modes of a Compressible Boundary Layer Flow Due to a Rotating Disk
Authors: Turkyilmazoglu M. 
Published: October 2005

In this paper, suction and injection effects are investigated theoretically on the structure of the lower branch neutral stability modes of three‐dimensional small disturbances imposed on the compressible boundary layer flow due to a rotating disk. In a recent study [1], it was demonstrated that the short‐wavelength stationary/nonstationary compressible crossflow vortex modes at sufficiently high Reynolds numbers with reasonably small scaled frequencies can be described by an asymptotic expansion procedure as set up in [2] for the incompressible stationary modes, which rigorously takes into account the nonparallel effects. Employing this rational asymptotic technique, it is shown here that the wavenumber and the orientation of the compressible lower branch modes are governed by an eigenrelation that is under the strong influence of a suction/injection parameter , which, when set to zero, the relation turns out to be the one obtained previously by Turkyilmazoglu [1] for zero‐suction compressible modes.The boundary layer growth contributes in the way of destabilizing all the modes, in particular for the compressible modes, though the wall cooling in the case of suction and the wall insulation and heating in the case of injection are found to persist to the destabilization for the modes in the vicinity of the stationary mode. From a linear stability analysis point of view, suction is found to be stabilizing, whereas injection enhances the instability as compared to the no suction through the surface of the disk. In both cases, positive frequency waves are found to be highly destabilized as compared to the waves having negative frequencies. The findings of the work are also fully supported after a comparison between the numerical results obtained from directly solving the linearized compressible system with a usual parallel flow approximation and the asymptotic compressible data obtained at a high Reynolds number.
The combination of shared family environment and individual‐specific developmental deviance as a cause for treated psychiatric morbidity in children
Authors: Gunther N. , Drukker M. , Feron F. , Korebrits A. , van Os J. 
Published: October 2005

Objective:  There is an incomplete understanding of why some children growing up in the same family are in need of treatment for psychiatric morbidity whilst their siblings are not. The present paper examined the possible role of individual‐specific developmental risk factors.Method:  Three case–control analyses were conducted: i) 80 children referred to the Community Mental Health Centre (cases) and 320 population controls, ii) 68 healthy siblings of cases and 272 population controls, and iii) 80 children and 68 healthy siblings. Measures of development and psychosocial circumstances were obtained from routine, longitudinal, standardized child medical records.Results:  Given shared family environments, additional presence of delays in speech and motor development contributed most to differential sibling mental health outcomes. In addition, cases displayed both earlier expression and more severe levels of developmental behavioural deviance than their healthy siblings, who in turn had higher levels of behavioural deviance than population controls.Conclusion:  In siblings sharing a familial risk environment, development of psychiatric morbidity may be canalized through additional individual‐specific developmental exposures.
A prospective study of offspring of women with psychosis: visual dysfunction in early childhood predicts schizophrenia‐spectrum disorders in adulthood
Authors: Schubert E. W. , Henriksson K. M. , McNeil T. F. 
Published: October 2005

Objective: Children with visual dysfunction have perinatal, neurological, visual‐perceptual and cognitive abnormalities, similar to schizophrenia patients. We prospectively investigated whether visual dysfunction in childhood selectively predicts adult schizophrenia‐spectrum disorders, and is related to childhood neurological abnormality.Method: Offspring of mothers with and without a history of psychosis were prospectively assessed with vision tests at 4 years, neurological examinations at 6 years, and interviews for psychiatric disorders at follow‐up (93% effective,n = 166) at 22 years.Results: In the total sample and high‐risk (HR) offspring, visual dysfunction at 4 years, and its severity, were associated only with schizophrenia‐spectrum disorders in adulthood, and with neurological abnormality at 6 years.Conclusion: Visual dysfunction at 4 years of age selectively predicts schizophrenia‐spectrum disorders in adulthood among HR offspring, this likely reflecting disturbed neurological development.
Triazine‐based tyrosinase inhibitors identified by chemical genetic screening
Authors: Ni‐Komatsu Li , Leung Jennifer K. , Williams Darren , Min Jaeki , Khersonsky Sonya M. , Chang Young‐Tae , Orlow Seth J. 
Published: October 2005

SummaryAs most of the available depigmenting agents exhibit only modest activity and some exhibit toxicities that lead to adverse side effects after long‐term usage, there remains a need for novel depigmenting agents. Chemical genetic screening was performed on cultured melanocytes to identify novel depigmenting compounds. By screening a tagged‐triazine library, we identified four compounds, TGH11, TGD10, TGD39 and TGJ29, as potent pigmentation inhibitors with IC50 values in the range of 10 μM. These newly identified depigmenting compounds were found to function as reversible inhibitors of tyrosinase, the key enzyme involved in melanin synthesis. Tyrosinase was further confirmed as the cellular target of these compounds by affinity chromatography. Kinetic data suggest that all four compounds act as competitive inhibitors of tyrosinase, most likely competing with l‐3,4‐dihydroxyphenylalanine (l‐DOPA) for binding to the DOPA‐binding site of the enzyme. No effect on levels of tyrosinase protein, processing or trafficking was observed upon treatment of melanocytes with these compounds. Cytotoxicity was not observed with these compounds at concentrations up to 20 μM. Our data suggest that TGH11, TGD10, TGD39 and TGJ29 are novel potent tyrosinase inhibitors with potential beneficial effects in the treatment of cutaneous hyperpigmentation.
Brassica napus L. Homeodomain Leucine‐Zipper Gene BnHB6 Responds to Abiotic and Biotic Stresses
Authors: YU Shun‐Wu , ZHANG Li‐Da , ZUO Kai‐Jing , TANG Dong‐Qin , SUN Xiao‐Fen , TANG Ke‐Xuan 
Published: October 2005

Abstract: A homeodomain leucine‐zipper (HD‐Zip) gene BnHB6 (GenBank accession No. AY3 36103) was isolated from oilseed rape (Brassica napus L.) following drought treatment through rapid amplification of cDNA ends (RACE). The full‐length cDNA of BnHB6 was 1611 bp and contained a 936‐bp open reading frame encoding 311 amino acids. Sequence analysis indicated that BnHB6 belonged to the HD‐Zip I subfamily. High‐stringency Southern boltting analysis showed that BnHB6 appeared in rape as a single copy but had homologous genes. Semi‐quantitative reverse transcription‐polymerase chain reaction (RT‐PCR) analysis revealed that BnHB6 was expressed in several tissues tested under control conditions, but that expression was significantly upregulated in shoots by mannitol, NaCl, cold treatment, anaerobic culture, wounding, H2O2, abscisic acid (ABA), and salicylic acid (SA) treatments, but not by ultraviolet treatment. Further RT‐PCR analysis revealed that BnHB6 was a late‐responsive gene, the expression of which was not activated by NaCl, cold treatment, H2O2, ABA, and SA at an early time point (20 min) of treatment in the shoot. However, after a certain period of treatment, the induced expression culminated and then declined until the next peak occurred. Tissue‐specific analysis revealed that BnHB6 was expressed at certain levels in the roots, shoots, and flowers, and the roots were found to respond to the osmotic stimuli more rapidly than shoots to increase the expression of BnHB6. The present study implies that BnHB6 plays a positive role as a regulator of biotic and abiotic stresses on growth during seedling establishment.(Managing editor: Li‐Hui ZHAO)
Identification of Random Amplified Polymorphic DNA Markers Linked to Sex Determination in Calamus simplicifolius C. F. Wei.
Authors: YANG Hua , GAN Si‐Ming , YIN Huang‐Tian , XU Huang‐Can 
Published: October 2005

Abstract: The random amplified polymorphic DNA (RAPD) molecular marker technique was used to determine the sex of Calamus simplicifolius C. F. Wei. In the present study, DNA samples were extracted individually from 10 male and 10 female plants. After a total of 1 040 decamer primers had been tested, an approximate 500‐bp male‐specific DNA fragment was generated with the S1443 primer. It is feasible to identify sex at the early stages of plant life, which is beneficial for improving breeding programs of this dioecious species. In addition, we have obtained a proper RAPD protocol that is useful for other species of rattan.(Managing editor: Li‐Hui ZHAO)
Functional Analysis of Nodulin‐like Promoter in Transgenic Cotton Plants
Authors: REN Mao‐Zhi , CHEN Quan‐Jia , LI Li , ZHANG Rui , GUO San‐Dui 
Published: October 2005

Abstract: For the first time, a nodulin‐like gene promoter was isolated from Gossypium hirsutum L. Guo Y18 by means of inverse PCR. Three plant expression vectors were constructed for functional identification of the promoter. These vectors were different only in promoter regions; three truncations of the nodulin‐like promoter took the place of the CaMV35S promoter in the pBI121 plant expression vector. Then, the three vectors were introduced into cotton plants via the pollen tube pathway. The expression patterns of the gus gene driven by nodulin‐like promoter truncations were investigated in the offspring of transgenic cotton plants. Histochemical GUS staining and fluorescence quantitative analysis were performed to achieve this goal. The results showed that the nodulin‐like promoter was a strong, highly reproductive organ‐specific promoter, which demonstrated a much higher driver activity than the CaMV35S promoter did in cotton reproductive organs, but relatively lower activity in vegetation. Identification of the speciality and strength‐determining regions of the nodulin‐like promoter was also undertaken.(Managing editor: Li‐Hui ZHAO)
Diversity in the Content of Some Nutritional Components in Husked Seeds of Three Wild Rice Species and Rice Varieties in Yunnan Province of China
Authors: CHENG Zai‐Quan , HUANG Xing‐Qi , ZHANG Yi‐Zheng , QIAN Jun , YANG Ming‐Zhi , WU Cheng‐Jun , LIU Jia‐Fu 
Published: October 2005

Abstract: In addition to rice (Oryza sativa L.) cultivars, there are three wild rice species, namely O. rufipogon Griff, O. officinalis Wall and O. granulata Baill, in Yunnan Province, China. Each species has different subtypes and ecological distributions. Yunnan wild rice species are excellent genetic resources for developing new rice cultivars. The nutritional components of the husked seeds of wild rice have not been investigated thus far. Herein, we report on the contents of total protein, starch, amylose, 17 amino acids, and five macro and five trace mineral elements in husked seeds from three wild rice species and six O. sativa cultivars. The mean (±SD) protein content in the husked rice of O. rufipogon, O. officinalis, and O. granulata was (14.5 ± 0.6)%, (16.3 ± 1.1)%, and (15.3 ± 0.5)%, respectively. O. officinalis III originating from Gengma had the highest protein content (19.3%). In contrast, the average protein content of six O. sativa cultivars was only 9.15%. The total content of 17 amino acids of three wild rice species was 30%‐50% higher than that of the six cultivars. Tyrosine, lysine, and valine content in the three wild rice species was 34%‐209% higher than that of the cultivars. However, the difference in total starch content among different O. sativa varieties or types of wild rice species was very small. The average amylose content of O. rufipogon, O. officinalis, and O. granulata was 12.0%, 9.7%, and 11.3%, respectively, much lower than that of the indica and japonica varieties (14.37%‐17.17%) but much higher than that of the glutinous rice cultivars (3.89%). The sulfur, phosphorus, magnesium, zinc, and ferrite content in the three wild rice species was 30%‐158% higher than that of the six cultivars. The considerable difference in some nutritional components among wild rice species and O. sativa cultivars represents a wide biodiversity of Yunnan Oryza species. Based on the results of the present study, it is predicted that some good genetic traits, especially high protein and ideal amylose content, of Yunnan wild rice species may be useful in improving the nutritional value of rice. This is the first report regarding the amino acid, mineral element, protein and amylose content of husked seeds of some Yunnan wild rice species that have important genetic characteristics for rice quality and nutritional value.(Managing editor: Wei WANG)
Effects of Logging on the Genetic Diversity of Quercus tiaoloshanica Chun et Ko in a Tropical Montane Forest of Hainan Island, Southern China
Authors: ZHENG Jian‐Wei , AN Shu‐Qing , CHEN Lin , LENG Xin , WANG Zhong‐Sheng , XIANG Hua‐Jun 
Published: October 2005

Abstract: Quercus tiaoloshanica Chun et Ko, which has a narrow range of distribution, is one of the important endemic species of the tropical montane rain forest on Hainan Island, southern China. Long‐term logging and habitat destruction have resulted in population decline and distribution retreat of Q. tiaoloshanica. To determine the impact of logging on the genetic diversity of Q. tiaoloshanica, the authors investigated the genetic structures using amplified fragment length polymorphism markers in four regenerated stands after logging and in one unlogged stand. Compared with the unlogged stand, the effective number of alleles per locus dropped by 1.0% in selective logging stands and by 2.0% in clear logging stands, corresponding to reductions of 3.8% and 5.2%, respectively, in mean Nei's gene diversity and 2.9% and 3.5%, respectively, in mean Shannon diversity index. No substantial genetic erosion was detected in any of the regenerated stands owing to the high tree density and high heterogeneity of the Q. tiaoloshanica stands investigated. Meanwhile, there was no natural regeneration of the species observed in a Dacrydium pierrei Hickel plantation 700 m away from the regenerated stands, suggesting the limited ability of seed dispersal of Q. tiaoloshanica. Clear logging should be undertaken cautiously because the total number of plant species dropped by 15.2% in the clear‐logged stands compared with the unlogged stand. To conserve the genetic diversity of this species, as well as the plant biodiversity of tropical forests, the habitats of Q. tiaoloshanica should be protected against exploitation in terms of agricultural or other forms of land use, and some mature trees should be preserved as seed sources to maintain an adequate regeneration base for this species in the management of logging.(Managing editor: Ya‐Qin HAN)
Ectopic Expression of the Pttknl Gene Induces Alterations in the Morphology of the Leaves and Flowers in Petunia hybrida Vilm.
Authors: HU Xin , WU Qing‐Feng , XIE Ya‐Hong , RU Hong , XIE Feng , WANG Xin‐Yu , WANG Chong‐Ying 
Published: October 2005

Abstract: A novel knottedl‐like homeobox (knox) gene, Pttknl (Populus tremula tremuloides knottedl), isolated from the cambial region of hybrid aspen, was introduced into Petunia hybrida Vilm. using the leaf‐disc method mediated by Agrobacterium. A series of novel phenotypes was observed in transgenic petunia plants, including the formation of ectopic spikes on the adaxial surface of corollas and small pet als on the abaxial surface of corollas, fusion of floral organs, shortening of corolla midribs, the formation of tumor‐like knots along the midrib on the abaxial surface and serrated lobs of corolla margins, and alterations in pet al color; except for changes in the leaves and plant architecture, RT‐PCR showed that the Pttknl gene was expressed in the leaves of different petunia transgenic plants, whereas no signal was detected in wild‐type plants. The possible function of Pttknl in leaf and flower development is discussed.(Managing editor: Li‐Hui ZHAO)