bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic control of B chromosome transmission rate in Zea mays ssp. mays (Poaceae)
Authors: Rosato Marcela , Chiavarino Amilcar M. , Naranjo Carlos A. , Puertas María J. , Poggio Lidia
Published: January 2018

We selected genotypes of high and low B chromosome transmission rate (TR) in a native race of maize (Pisingallo) from northwest Argentina. We made 20 female OB male IB and 20 f.IB m.OB crosses. The former (GOm) showed a large variation of B TR, with a mean of TR ± SE = 0.52 ± 0.06, ranging from 0.17 to 0.98. In the latter (GOf) the mean was TR = 0.47 ± 0.02 ranging from 0.31 to 0.58. Plants showing the highest and the lowest TR were selected to constitute the progenitors of the G1 generations. We made 19 f.0B m.2B crosses, studying 24–30 plants per cross. The TR of the high (H) and low (L) lines in Glm (GlmH and GlmL) significantly differed (TRH = 0.65 ± 0.03, TRL = 0.40 ± 0.01), indicating that the H and L lines are different groups. The large variation in male TR suggests that preferential fertilization of gametes carrying B chromosomes does not always occur. We also selected plants showing high and low TR in the progenies of f.lB m.OB crosses (GOf), and made 24 f.1B m.0B crosses, studying 23–30 plants per cross. The TRs of the H and L lines in G1f (GlfH and GlfL) were significantly different (TRH = 0.48 ± 0.025, TRL = 0.40 ± 0.02). The TRs in G0f and G1fL were significantly different (TR = 0.47 ± 0.02 and 0.40 ± 0.02, respectively), while this was not the case between G0f and G1fH. Our results demonstrate the existence of genotypes controlling B TR in this native population of maize.
Crop‐to‐weed gene flow in the genus Sorghum (Poaceae): Spontaneous interspecific hybridization between johnsongrass, Sorghum halepense, and crop sorghum, S. bicolor
Authors: Arriola Paul E. , Ellstrand Norman C.
Published: January 2018

The role of crop‐to‐weed gene flow is often controversial and overlooked. As a consequence, the likelihood of spontaneous crop‐to‐weed hybridization in most crop/weed systems is generally unknown. The lack of data relating to the formation of crop/weed hybrids has particular contemporary significance when considering the wide scale commercial release of transgenic crop plants and the potential for escape of engineered genes via crop‐to‐weed hybridization. We created an experimental system whereby we could examine the incidence and rate of spontaneous crop‐to‐weed hybridization between Sorghum bicolor and S. halepense, johnsongrass. An isozyme marker was used to identify hybrid plants through progeny testing. Incidence and rate of hybridization were highly variable with respect to weed distance from the crop, location of the study site, and year the study was performed. Crop/weed hybrids were detected at distances of 0.5–100 m from the crop. Interspecific hybridization can and does occur in this system at a substantial and measurable rate. Transgenes introduced into crop sorghum can be expected to have the opportunity to escape cultivation through interspecific hybridization with johnsongrass. Traits that prove to be beneficial to weeds possessing them can be expected to persist and spread. This is an issue that needs to be addressed when developing biosafety guidelines for the commercial release of transgenic sorghums.
Tristyly in the endangered Mascarene Island endemic Hugonia serrata (Linaceae)
Authors: Thompson John D. , Pailler Thierry , Strasberg Dominique , Manicacci Domenica
Published: January 2018

Tristyly is a rare floral polymorphism known to occur in only five flowering plant families. One unresolved and potential additional case of tristyly concerns the genus Hugonia in the Linaceae. Here we confirm the existence of tristyly in the genus by reporting floral measurements made on Hugonia serrata Lam., an extremely rare species endemic to the Mascarene Islands of La Réunion and Mauritius in the southern Indian Ocean. We conducted an extensive search of all natural habitats on La Réunion Island where the species had been previously reported. Twenty‐eight individuals were found, of which nine were in flower. Of the nine flowering individuals five had long‐styled flowers with the stigmas placed above the two levels of anthers, three had intermediate length styles with the stigmas placed between the two anther levels, and one had stigmas placed below the two anther levels, i.e., three floral morphs could be identified based on the sequence of stigma and anther positions. Reciprocity and precision indices calculated for sexual organ length in each morph confirm that this variation is well within the range of values observed by previous workers on other tristylous species in other families. Our empirical data confirm the existence of tristyly in the genus Hugonia, thereby raising the number of known families in which tristyly occurs to six. Pollen size, pollen number, and anther length increased slightly with stamen length, but the low number of plants precludes statistical tests of these trends. A bibliographic survey suggests that tristyly may occur in several other species of the genus.
Occurrence and evolutionary significance of RESISTANT CELL WALLS IN CHAROPHYTES AND BRYOPHYTES
Authors: Kroken Scott B. , Graham Linda E. , Cook Martha E.
Published: January 2018

A survey of charophycean green algal and bryophyte taxa revealed the frequent occurrence of vegetative cell walls that were characterized by a specific form of autofluorescence and resistance to high temperature acid treatment (acetolysis). The time of production and the location of resistant, autofluorescent cell walls varied among charophyte and bryophyte taxa in patterns that suggest that bryophytes inherited the capacity to produce such walls from charophyte ancestors. A number of charophytes produced resistant walls in response to desiccation stress, suggesting an evolutionarily early adaptive response. Coleochaete was unique among charophytes, but similar to all bryophytes tested in that sexual reproduction induced autofluorescence in cell walls of well‐hydrated tissues at the placental junction. Maternal tissues in apical portions of the pseudoseta bearing Sphagnum sporophytes were characterized by autofluorescent, acetolysis‐resistant cell walls similar to those observed in maternal cells adjacent to Coleochaete zygotes. These observations suggest that cell–cell stimulus–response interactions regulate deposition of autofluorescent compounds in placental cell walls, and that this characteristic may have been shared by the earliest embryophytes and their charophyte ancestors. Various bryophytes deposit autofluorescent, acid‐resistant compounds at other adaptively significant sites including sporangial epidermis, spiral thickenings of elaters, rhizoids, and leaves in the special case of Sphagnum moss. Sphagnum and liverwort sporangial epidermis, which had been subjected to acetolysis or strong acid procedures commonly used to release microfossils from rock matrices, resembled published photographs of Ordovician–Devonian microfossils consisting of cellular scraps that have been attributed to earliest land plants. Our work suggests that at least some of these fossils, previously thought to represent “dispersed cuticles,” could be reinterpreted as earliest known remains of plant sporophytic tissues, and that they may be homologous with resistant sporangial epidermis of modern bryophytes. In general, the patterns of occurrence of resistant, autofluorescent cell walls in charophytes and bryophytes suggest repeated exaptation. Regulation of deposition appears to have been modified through time, so that resistant wall compounds have had a sequence of functions: desiccation resistance and/or microbial resistance in lower charophytes, a role in embryogenesis in Coleochaete and embryophytes, and finally, decay resistance in innovative structures that characterize bryophytes, such as rhizoids, sporangial epidermis, and elaters.
Genotypic variation in agamospermous Erigeron compositus (Asteraceae)
Authors: Noyes Richard D. , Soltis Douglas E.
Published: January 2018

Few integrative analyses of the structure of agamospermous plant populations have been conducted. Erigeron compositus occurs in montane western North America and comprises both sexual and agamospermous populations. Sexual E. compositus has previously been characterized as outcrossing and predominantly diploid (2n = 18). Agamic E. compositus is usually hexaploid (2n = 54), though counts herein range from 2n = 36 to 2n = 80. Starch‐gel electrophoresis, cytology, and analysis of pollen production were used to evaluate variation within and among agamospermous populations. Fifteen enzyme loci were used to identify 24 unique multilocus genotypes in seven populations, an average of 3.4 genotypes per population. Proportion of distinct genotypes per population sample size (GIN) and measures of genetic diversity (D) and evenness (E) are 0.10, 0.48, and 0.61, respectively, which indicate that E. compositus maintains levels of diversity similar to other agamospermous taxa. Most agamospermous populations are mosaics comprising groups of genetically distinct individuals that are frequently distinguished by cytotype and capacity for pollen production. The geographical and ecological separation of sexual and agamospermous populations make it unlikely that gene flow from sexual populations is a direct source of genetic variation in agamospermous populations. Instead, crossing between genetically distinct facultative agamosperms probably accounts for most variation. Genetic and morphological evidence document one such putative crossing event. Agamospermous E. compositus is very similar genetically to sexual E. compositus. Allozyme analysis further shows that genetic variation in agamospermous populations is partitioned among a few highly heterozygous genotypes, whereas sexual populations maintain numerous genotypes of relatively low heterozygosity.
Biosystematic studies on the genus Isoetes (Isoetaceae) in Japan. II. Meiotic behavior and REPRODUCTIVE MODE OF EACH CYTOTYPE
Authors: Takamiya Masayuki , Watanabe Mitsuru , Ono Kanji
Published: January 2018

Meiotic behaviors and reproductive modes of Japanese Isoetes were studied. The hexaploid (2n = 66) and the octaploid (2n = 88) of I. japonica consistently formed 33 and 44 bivalents, respectively, at diakinesis and/or metaphase I in both micro‐ and megaspore mother cells. The tetraploid (2n = 44) of I. sinensis formed 22 bivalents and its hexaploid made 33 bivalents in both types of spore mother cells. At diakinesis and/or metaphase I of microspore mother cells in I. asiatica with 2n = 22, 11 bivalents were detected. Because behaviors of meiosis in all cytotypes mentioned above were quite regular and plants yielded normal‐appearing spores, they should reproduce sexually. Aneuploids of I. japonica with 2n = 87 formed 43 bivalents and one univalent, and I. sinensis with 2n = 65 formed 32 bivalents and one univalent in microspore mother cells. Meiosis of both cytotypes was almost regular and yielded microspores of normal appearance. In the heptaploid (2n = 77) of I. japonica, a configuration of 22 bivalents and 33 univalents was detected in micro‐ and megaspore mother cells, and various irregularities were observed throughout the meiotic divisions. Therefore, the genomic formula of the heptaploid is symbolized as AABBCDE, and the heptaploid is a sterile F, hybrid between the hexaploid (AABBCC) and the octaploid (AABBDDEE) of I. japonica. Since diploid and even‐numbered polyploids regularly formed bivalents and odd‐numbered ones displayed irregularities, allopolyploidy should act as a significant speciation mechanism in this genus.
Another perspective on cytoevolution in Lobelioideae (Campanulaceae)
Authors: Stace Helen M. , James S. H.
Published: January 2018

The Lobelioideae is a cosmopolitan group whose cytoevolution is discussed on a model of primitively high diploid chromosome numbers, in which x = 14 is relatively plesiomorphic and x = 21 may be even more plesiomorphic. This model is suggested from the high frequency of lobelioid genera with x = 14, the probably plesiomorphic condition of x = 17 in the sister group Campanuloideae (Campanulaceae), and the primitive x = 15 in Stylidiaceae (Campanulales). It contrasts with that for a primitive x = 7 and paleopolyploidy to higher chromosome numbers. In our analysis, the genus Lobelia shows three broad cytoevolutionary groups, which probably have phylogenetic and infrageneric taxonomic significance: (1) woody diploids with x = 21 in Chile and woody diploids with x = 14 in Africa, Asia, and Hawaii; (2) herbaceous diploids with several series of dysploid chromosome numbers n = 19, 13, 12, 11, 10, 9, 8, 7, 6, mainly in Africa and Australia; (3) widespread and speciose herbaceous taxa based on a very derived n = 7, with recent frequent euploid rises (neopolyploidy) at or below the species level in subgenus Lobelia and allied or segregate genera. Other woody and herbaceous lobeliad genera have comparable cytoevolutionary patterns. New chromosome counts for Australian Lobelia, Pratia, and Isotoma illustrate the last two cytoevolutionary groups.
Genetic variation in populations of the arctic perennialPedicularis dasyantha(Scrophulariaceae), on Svalbard, Norway
Authors: Odasz Ann Marie , Savolainen Outi
Published: January 2018

Isozyme variability was examined in 13 geographically isolated populations of the endemic arctic hairy lousewort (Pedicularis dasyantha) in the Svalbard Archipelago, 80° N latitude, Norway. Of the 23 enzyme systems screened on five buffer systems 18 were interpretable. Of the 31 reliable loci, only 6‐phosphogluconate dehydrogenase (6‐Pgd), was polymorphic. However, no heterozygotes were detected. Frequencies for allele 1 among the populations varied from 1.00 in the north to 0.00 in the south and 0.53 in the central “overlap” region. At the species level the mean number of alleles per locus (A) was 1.03. Percentage of polymorphic loci (P) was 3%. Expected heterozygosity (He) was 0.016. At the population level the mean number of alleles per locus was 1.01, and 1.1% of the loci were polymorphic.Hewas 0.004. These values are low compared to endemic, widespread, selling, and outcrossed species. Flower color morphs were distinct. They varied within and among the 13 populations. The frequency of color morphs coincided with allele frequencies of 6‐PGD: allele 1 was found in dark purple morphs, and allele 2 was found in light morphs. This species shows more isozyme genetic variability than the five other species reported in the genus but generally less variation than other species with limited regional distributions. Low‐level genetic variation in this diploid species may be a result of colonization events coupled with genetic drift, founder effects, and strong natural selection. Additional factors include the self‐compatible reproductive system and the long‐lived perennial habit.
Differentiation of bundle sheath, mesophyll, and distinctive cells in the C4 grass Arundinella hirta (Poaceae)
Authors: Dengler Nancy G. , Donnelly Petra M. , Dengler Ronald E.
Published: January 2018

The C4 grass Arundinella hirta is characterized by unusual leaf blade anatomy: veins are widely spaced and files of bundle‐sheath‐like cells, the distinctive cells, form longitudinal strands that are not associated with vascular tissue. While distinctive cells (DCs) appear to function like bundle sheath cells (BSCs), they differ developmentally in two ways: they are derived from ground meristem rather than procambium and they are formed 1–2 plastochrons later. This study describes ultrastructural features of differentiating of BSCs, DCs, and associated mesophyll cells (MCs) during leaf development. BSCs and DCs differ from adjacent MCs by undergoing earlier cell enlargement, greater rates of chloroplast enlargement, reduction of chloroplast thylakoids at late stages of differentiation, more extensive starch formation, greater wall thickening, and deposition of a suberin lamella. The precocious delimitation of the bundle sheath layer is reflected in earlier BSC enlargement and vacuole growth. Derivation of DCs from ground meristem is correlated with late developmental changes in chloroplast size, wall thickness, and plasmodesmatal density. Despite these differences in timing of events, particularly at early stages, the development of the specialized structural features of BSCs and DCs is essentially similar. Thus, proximity to vascular tissue appears to be nonessential for the coordination and regulation of BSC‐ and MC‐specific developmental events.
Factors affecting vegetation dieback of an oligohaline marsh in coastal Louisiana: Field manipulation of salinity and submergence
Authors: Webb Eric C. , Mendelssohn Irving A.
Published: January 2018

Vegetation dieback is an important component of wetland loss in low salinity marshes of coastal Louisiana. A field experiment was conducted to determine the factors responsible for vegetation dieback within oligohaline marshes of Louisiana. Sections of marsh, dominated by Sagittaria lancifolia L., were transplanted into one of four locations depending on the treatment: (1) increased submergence—sods were lowered 15 cm below the donor marsh surface, (2) increased salinity—sods were transplanted into a higher salinity marsh and adjacent dieback pond, (3) increased salinity and submergence—sods were transplanted into a higher salinity marsh and adjacent dieback pond at 15 cm below the marsh surface, and (4) control—sods were exhumed and replaced at the ambient elevation of the donor marsh. Plant biomass and edaphic characteristics were measured after 5 mo. An increase in submergence caused decreased plant growth of the S. lancifolia‐dominated marsh community. An increase in salinities to 4–5 g/kg were not detrimental to plant growth. Although saltwater intrusion alone did not cause decreased growth of the S. lancifolia‐dominnled plant community, the combination of saltwater intrusion and increased plant submergence caused the greatest decrease in plant growth due to increased toxic sulfides and a likely reduction in the uptake of NH4‐N by the wetland vegetation. This illustrates that the dieback of oligohaline marsh vegetation can be alleviated by decreasing plant submergence even at salinities as high as 4.6 g/kg.
Diversification rates in a temperate legume clade: Are there “so many species” of Astragalus (Fabaceae)?
Authors: Sanderson Michael J. , Wojciechowski Martin F.
Published: January 2018

Astragalus, the largest genus of flowering plants, contains upwards of 2500 species. Explanations for this exceptional species diversity have pointed to unusual population structure or modes of speciation. Surprisingly, however, three different statistical analyses indicate that diversification rates in Astragalus are not exceptionally high compared to its closest relatives. Instead, rates are high throughout the “Astragalean clade,” a much broader radiation distributed throughout the temperate zone. The increase in diversification rate is associated with the origin and divergence of this clade from common ancestors of it and several much less diverse and more narrowly distributed Asian genera. This suggests that causal factors in the shift toward higher rates of diversification must be due not to factors unique to Astragalus, but to characteristics common to the entire Astragalean clade. However, this larger clade has never been circumscribed in classifications based on morphological data. This raises the possibility that the causes of increased diversification may not be due to morphological innovation, but may instead be related to ecological factors or cryptic physiological or biochemical features.
Retracted: RNA interference‐mediated silencing of S100B improves nerve function recovery and inhibits hippocampal cell apoptosis in rat models of ischemic stroke
Authors: Zhang Jin‐Hua , Li Jiang‐Kun , Ma Li‐Li , Lou Ji‐Yu
Published: January 2018

Ischemic stroke is the leading cause of worldwide mortality and long‐term disability in adults. This study aims to explore the effects of RNA interference (RNAi)‐mediated silencing of the S100B gene on nerve function recovery and morphological changes of hippocampus cells in rat models with ischemic stroke. Sixty Wistar rats were assigned into different group. S100B and Caspase 3 mRNA and protein expressions were evaluated by RT‐qPCR and Western blotting. Positive rate of S100B, NeuN, and MAP2 expressions were detected by immunohistochemistry (IHC). Water content, malondialdehyde (MDA) levels, and superoxide dismutase (SOD) activity in brain tissues were measured. Enzyme‐linked immunosorbent assay (ELISA) was employed to detect serum levels of TNF‐α and IL‐1β. A neurological severity score (NSS) was used to test nerve function. TUNEL assay was used to determine hippocampal cell apoptosis. Downregulation of S100B showed a lower number of S100B immune positive cells, but higher NeuN and MAP2‐positive cells, increased SOD level, declined MDA level, prominently faster recovery of neurological function, decreased TRCS, TCTP, TCFP, and IE levels, an obvious increase in the number of survival neurons, a decrease in the number of apoptotic cells, notably decreased TNF‐α and IL‐1β contents, as well as infarct volume, an obvious decrease in positive hippocampal cell Caspase 3 expression and protein expressions of Caspase 3 and cleaved Caspase 3. This study provides data to suggest that RNAi‐mediated silencing of S100B gene could improve the recovery of nerve function while inhibiting apoptosis of hippocampal cells in rats with ischemic stroke.
The effect of chronic high insulin exposure upon metabolic and myogenic markers in C2C12 skeletal muscle cells and myotubes
Authors: Turner Mark C. , Player Darren J. , Martin Neil R.W. , Akam Elizabeth C. , Lewis Mark P.
Published: January 2018

Skeletal muscle is an insulin sensitive tissue and accounts for approximately 80% of post‐prandial glucose disposal. This study describes the effects of insulin, delivered for 72 h, to skeletal muscle myoblasts during differentiation or to skeletal muscle myotubes. After chronic treatment, cultures were acutely stimulated with insulin and analyzed for total and phosphorylated Akt (Ser473), mRNA expression of metabolic and myogenic markers and insulin‐stimulated glucose uptake. Skeletal muscle cells differentiated in the presence of insulin chronically, reduced acute insulin stimulated phosphorylation of Akt Ser473. In addition, there was a reduction in mRNA expression of Hexokinase II (HKII), GLUT4 and PGC‐1α. Insulin‐stimulated glucose uptake was attenuated when cells were differentiated in the presence of insulin. In contrast, myotubes exposed to chronic insulin showed no alterations in phosphorylation of Akt Ser473. Both HKII and GLUT4 mRNA expression were reduced by chronic exposure to insulin; while PGC‐1α was not different between culture conditions and was increased by acute insulin stimulation. These data suggest that there are differential responses in insulin signalling, transcription, and glucose uptake of skeletal muscle cells when cultured in either the presence of insulin during differentiation or in myotube cultures.
Curcumin on the “flying carpets” to modulate different signal transduction cascades in cancers: Next‐generation approach to bridge translational gaps
Authors: Celik Hulya , Aydin Tuba , Solak Kubra , Khalid Sumbul , Farooqi Ammad A.
Published: January 2018

Curcumin, a bioactive and pharmacologically efficient component isolated from Curcuma longa has attracted considerable attention because of its ability to modulate diverse cellular and physiological pathways. WNT, TGF/SMAD, NOTCH, and SHH are fundamentally different signaling cascades, but their choreographed activation is strongly associated with cancer development and progression. In this review we have attempted to set spotlight on regulation of different cell signaling pathways by curcumin in different cancers. We partition this multi‐component review into in‐depth biological understanding of various signal transduction cascades and how curcumin targets intracellular signal transducers of deregulated pathways to inhibit cancer development and progression. Rapidly broadening landscape of both established and candidate oncogenic driver mutations identified in different cancers is a major stumbling block in the standardization of drugs having significant clinical outcome. Intra and inter‐tumor heterogeneity had leveraged the complexity of therapeutic challenges to another level. Multi‐pronged approach and molecularly guided treatments will be helpful in improving the clinical outcome.
Increased N6‐methyladenosine causes infertility is associated with FTO expression
Authors: Ding Chenyue , Zou Qinyan , Ding Jie , Ling Mingfa , Wang Wei , Li Hong , Huang Boxian
Published: January 2018

The N6‐methyladenosine (m6A) modification plays a central role in epigenetic regulation of the mammalian transcriptome. m6A can be demethylated by the fat mass‐ and obesity‐associated (FTO) protein and the α‐ketoglutarate‐dependent dioxygenase alkB homolog 5 (ALKBH5) protein. Much less is known about that whether m6A content is involved in POI (premature ovarian insufficiency) disease. In this case‐controlled study, 69 POI and 53 tubal occlusion patients were recruited from the reproduction centers in our hospital. For the POI animal model experiment, ovarian tissue was obtained from ten POI and nine healthy mice. An m6A test kit was developed to determine the m6A content in the RNA, and qPCR and western blot were used to examine the mRNA and protein expression levels of FTO and ALKBH5. FACS was used to measure the levels of proliferation and apoptosis, and siRNA was used to establish FTO and ALKBH5 knockdown cell lines. Our results showed that the m6A content in the RNA from POI patients and POI mice was significantly higher than control groups and that POI was characterized by the content of m6A. The mRNA and protein expression levels of FTO were significantly lower in the POI patients than control group and were associated with a risk of POI. These data suggest that the decreased mRNA and protein expression levels of FTO may be responsible for the increase in m6A in POI, which may further increase the risk of complications of POI. High m6A should be investigated further as a novel potential biomarker of POI.
Selenate removal in biofilm systems: effect of nitrate and sulfate on selenium removal efficiency, biofilm structure and microbial community
Authors: Tan Lea Chua , Espinosa‐Ortiz Erika J , Nancharaiah Yarlagadda V , van Hullebusch Eric D , Gerlach Robin , Lens Piet NL
Published: January 2018

BACKGROUND

Selenium (Se) discharged into natural waterbodies can accumulate over time and have negative impacts on the environment. Se‐laden wastewater streams can be treated using biological processes. However, the presence of other electron acceptors in wastewater, such as nitrate (NO3‐) and sulfate (SO42‐), can influence selenate (SeO42‐) reduction and impact the efficiency of biological treatment systems.

RESULTS

SeO42‐ removal by biofilms formed from an anaerobic sludge inoculum was investigated in the presence of NO3‐ and SO42‐ using drip flow reactors operated continuously for 10 days at pH 7.0 and 30 °C. The highest total Se (∼60%) and SeO42‐ (∼80%) removal efficiencies were observed when the artificial wastewater contained SO42‐. A maximum amount of 68 μmol Se cm‐2 was recovered from the biofilm matrix in SO42‐ + SeO42‐ exposed biofilms and biofilm mass was 2.7‐fold increased for biofilms grown in the presence of SO42‐. When SeO42‐ was the only electron acceptor, biofilms were thin and compact. In the simultaneous presence of NO3‐ or SO42‐, biofilms were thicker (> 0.6 mm), less compact and exhibited gas pockets.

CONCLUSION

The presence of SO42‐ had a beneficial effect on biofilm growth and the SeO42‐ removal efficiency, while the presence of NO3‐ did not have a significant effect on SeO42‐ removal by the biofilms. © 2018 Society of Chemical Industry
Morpho‐palynological study of Cyperaceae from wetlands of Azad Jammu and Kashmir using SEM and LM
Authors: Butt Maryam Akram , Zafar Muhammad , Ahmad Mushtaq , Sultana Shazia , Ullah Fazal , Jan Gul , Irfan Ali , Naqvi Syeda Andleeb Zahra
Published: January 2018

In this study 12 species of Cyperaceae have been studied for quantitative and qualitative observation of pollen grains through Light and scanning electron microscopy. Pollens of 12 species of Cyperaceae from different wetlands of Azad Jammu and Kashmir were collected. Morphological characters of pollen grains were then investigated under the Light and Scanning electron microscope. Two pollen types have been observed apolar and heteropolar. Shape of pollens was prolate (4 spp), sub‐spheroidal (7 spp), and oblate (1 spp). Variation observed in exine sculpturing granular (4 spp), reticulate (1 spp), areolate‐punctate (3 spp), and psilate (2 spp). Polar to equatorial ratio and fertility percentage of the pollens were also studied. Based on these micromorphlogical characters of pollens taxonomic keys have been made for the accurate identification of the members of Cyperaceae. The characteristics studied in present research work are very much valuable taxonomically and phytochemically for the identification of species of family Cyperaceae. Light microscope (LM) and Scanning electron microscope (SEM) were used for pollen observation, which play vital role in the taxonomical identification of species and provide sufficient information for taxonomist.
Describing one generic and two new species record to the flora of Pakistan using LM and SEM methods
Authors: Jamshed Shayan , Ullah Asad , Khan Raees , Hussain Altaf
Published: January 2018

Common mulberry weed (Fatoua villosa (Thunb.) Nakai) and creeping amaranth (Amaranthus crassipes Schlecht) are reported for the first time in Pakistan's flora as these were not listed in any other literature nor identified before in Pakistan. Plants were found as a result of taxonomic studies performed in 2013 in Peshawar, Pakistan. Detail study was performed for the exact identification. Morphological results were compared with Flora of China and Flora of North America. Plant distribution along with its habitat and adjacent species was also recorded. Scanning electron and light microscopy was performed for the confirmation of epidermal appendages on leaf epidermis and palyno‐morphological characters.
Characterizing pentad rainfall variations during the North‐East Indian monsoon season over the southeastern peninsular India
Authors: Shanmugasundaram Jothiganesh , Lee Eungul , Srinivasan Govindarajalu
Published: January 2018

North‐East Indian Monsoon rainfall (NEIMR) during October–December is of immense socio‐economic importance to the agriculture‐dependent population in the southeastern peninsular India. NEIMR is subject to extreme year‐to‐year and intra‐seasonal variability that needs to be understood to enhance climate resilience. In this study, we employed hidden Markov model to characterize the spatio‐temporal variations of NEIMR at pentad time step and its probability of occurrence during 1982–2014. The results indicated the dominant presence of three rainfall states during the NEIMR season, which were the wet (State‐1), coastal wet (State‐2), and dry (State‐3) states. Seasonal total NEIMR was significantly and positively correlated with the frequency of State‐1, whereas it was negatively correlated with that of State‐3, indicating a crucial role of the rainfall states in determining water requirements in the southeastern peninsular India. The rainfall states were associated with distinctive atmospheric circulation and surface temperature conditions, particularly the wet (State‐1) and dry (State‐3) conditions. Wet conditions were characterized by enhanced cyclonic activities and increased moisture convergence at 850 hPa over the southeastern peninsular India and its neighbouring oceanic regions (Bay of Bengal and Indian Ocean). In contrast, dry conditions were associated with anticyclonic circulation and reduced moisture convergence at 850 hPa. The plausible physical mechanisms behind the wet (dry) condition could be that anomalous warmer (cooler) land temperature above 20°N induced lower (higher) sea level pressure anomalies and drove anomalous southwesterly (northeasterly) surface winds over the NEIMR region. These anomalous surface winds and the associated lower level cyclonic (anticyclonic) circulations could enhance (suppress) moisture transport from the convergence regions over the Bay of Bengal and northern Indian Ocean into the southern peninsular India. This study revealed the pentad variability of NEIMR with the classified three rainfall states and identified the key atmospheric circulation and surface temperature conditions linked to these rainfall states.
Magnetic separation coupled with high‐performance liquid chromatography–mass spectrometry for rapid separation and determination of lignans in Schisandra chinensis
Authors: Piao Jishou , Liu Lu , Wang Sihong , Shang Hai‐Bo , He Miao , Quan Ninghai , Li Donghao
Published: January 2018

Despite the strong antihepatotoxic, antioxidant, and antitumor properties of lignans from Schisandra chinensis, their applications in new drug development, bioscience and functional foods, etc. are limited because of their low abundance and complex coextractions. In this study, a magnetic separation method has been developed based on polyethylenimine‐modified magnetic nanoparticles to rapidly and effectively separate and purify the lignans from S. chinensis crude extracts through cation–π interaction and electrostatic adsorption. The magnetic nanoparticles were characterized by transmission electron microscopy, vibrating sample magnetometry, Fourier transform infrared spectroscopy, and X‐ray diffraction. Polyethylenimine‐modified magnetic nanoparticles showed a spherical‐shaped morphology and the average size was about 10 nm with superparamagnetism. Under the pH 7.4, polyethylenimine modified magnetic nanoparticles can remove a lot of coextracts. The range of detection limits and quantification limits was 0.27–0.34 and 0.89–1.13 ng/mL, respectively. Compared with other common methods, the magnetic separation method proposed in this study is much simpler and more effective through both strong cation–π interaction and electrostatic interaction.
Photografted methacrylate‐based monolithic columns coated with cellulose tris(3,5‐dimethylphenylcarbamate) for chiral separation in CEC
Authors: Noel Echevarria Romina , Carrasco‐Correa Enrique Javier , Keunchkarian Sonia , Reta Mario , Herrero‐Martinez José Manuel
Published: January 2018

A chiral capillary monolithic column for enantiomer separation in capillary electrochromatography was prepared by coating cellulose tris(3,5‐dimethylphenylcarbamate) on porous glycidyl methacrylate‐co‐ethylene dimethacrylate monolith in capillary format grafted with chains of [2(methacryloyloxy)ethyl] trimethylammonium chloride. The surface modification of the monolith by the photografting of [2(methacryloyloxy)ethyl] trimethylammonium chloride monomer as well as the coating conditions of cellulose tris(3,5‐dimethylphenylcarbamate) onto the grafted monolithic scaffold were optimized to obtain a stable and reproducible chiral stationary phase for capillary electrochromatography. The effect of organic modifier (acetonitrile) in aqueous mobile phase for the enantiomer separation by capillary electrochromatography was also investigated. Several pairs of enantiomers including acidic, neutral, and basic analytes were tested and most of them were partially or completely resolved under aqueous mobile phases. The prepared monolithic chiral stationary phases exhibited a good stability, repeatability, and column‐to‐column reproducibility, with relative standard deviations below 11% in the studied electrochromatographic parameters.
Quality evaluation of no‐reference MR images using multidirectional filters and image statistics
Authors: Jang Jinseong , Bang Kihun , Jang Hanbyol , Hwang Dosik ,   for the Alzheimer's Disease Neuroimaging Initiative
Published: January 2018

Purpose

This study aimed to develop a fully automatic, no‐reference image‐quality assessment (IQA) method for MR images.

Methods

New quality‐aware features were obtained by applying multidirectional filters to MR images and examining the feature statistics. A histogram of these features was then fitted to a generalized Gaussian distribution function for which the shape parameters yielded different values depending on the type of distortion in the MR image. Standard feature statistics were established through a training process based on high‐quality MR images without distortion. Subsequently, the feature statistics of a test MR image were calculated and compared with the standards. The quality score was calculated as the difference between the shape parameters of the test image and the undistorted standard images.

Results

The proposed IQA method showed a >0.99 correlation with the conventional full‐reference assessment methods; accordingly, this proposed method yielded the best performance among no‐reference IQA methods for images containing six types of synthetic, MR‐specific distortions. In addition, for authentically distorted images, the proposed method yielded the highest correlation with subjective assessments by human observers, thus demonstrating its superior performance over other no‐reference IQAs.

Conclusion

Our proposed IQA was designed to consider MR‐specific features and outperformed other no‐reference IQAs designed mainly for photographic images. Magn Reson Med 80:914–924, 2018. © 2018 International Society for Magnetic Resonance in Medicine.
Crystal structure of yeast nitronate monooxygenase from Cyberlindnera saturnus
Authors: Agniswamy Johnson , Reis Renata A.G. , Wang Yuan‐Fang , Smitherman Crystal , Su Dan , Weber Irene , Gadda Giovanni
Published: January 2018

Nitronate monooxygenase (NMO) is an FMN‐dependent enzyme that oxidizes the neurotoxin propionate 3‐nitronate (P3N) and represents the best‐known system for P3N detoxification in different organisms. The crystal structure of the first eukaryotic Class I NMO from Cyberlindnera saturnus (CsNMO) has been solved at 1.65 Å resolution and refined to an R‐factor of 14.0%. The three‐dimensional structures of yeast CsNMO and bacterial PaNMO are highly conserved with the exception of three additional loops on the surface in the CsNMO enzyme and differences in four active sites residues. A PEG molecule was identified in the structure and formed extensive interactions with CsNMO, suggesting a specific binding site; however, 8% PEG showed no significant effect on the enzyme activity. This new crystal structure of a eukaryotic NMO provides insight into the function of this class of enzymes.
Probing subtle conformational changes induced by phosphorylation and point mutations in the TIR domains of TLR2 and TLR3
Authors: Mahita Jarjapu , Sowdhamini Ramanathan
Published: January 2018

Extensive research performed on Toll‐like receptor (TLR) signaling has identified residues in the Toll/interleukin‐1 receptor (TIR) domains that are essential for its proper functioning. Among these residues, those in BB loop are particularly significant as single amino acid mutations in this region can cause drastic changes in downstream signaling. However, while the effect of these mutations on the function is well studied (like the P681H mutation in TLR2, the A795P mutation in TLR3, and the P714H mutation in TLR4), their influence on the dynamics and inter‐residue networks is not well understood. The effects of local perturbations induced by these mutations could propagate throughout the TIR domain, influencing interactions with other TIR domain‐containing proteins. The identification of these subtle changes in inter‐residue interactions can provide new insights and structural rationale for how single‐point mutations cause drastic changes in TIR–TIR interactions. We employed molecular dynamics simulations and protein structure network (PSN) analyses to investigate the structural transitions with special emphasis on TLR2 and TLR3. Our results reveal that phosphorylation of the Tyr 759 residue in the TIR domain of TLR3 introduces rigidity to its BB loop. Subtle differences in the intra BB loop hydrogen bonding network between TLR3 and TLR2 are also observed. The PSN analyses indicate that the TIR domain is highly connected and pinpoints key differences in the inter‐residue interactions between the wild‐type and mutant TIR domains, suggesting that TIR domain structure is prone to allosteric effects, consistent with the current view of the influence of allostery on TLR signaling.
Design, synthesis, fungicidal property and QSAR studies of novel β‐carbolines containing urea, benzoylthiourea and benzoylurea for the control of rice sheath blight
Authors: Zhang Zhi‐Jun , Zeng Yong , Jiang Zhi‐Yan , Shu Ben‐Shui , Sethuraman Veeran , Zhong Guo‐Hua
Published: January 2018

BACKGROUND

Rice sheath blight is a globally important rice disease. Unfortunately, this critical disease has not been effectively controlled, and the intensive and continuous use of the same fungicide might increase the risk of resistance development in the pathogen. To discover new active agents against rice sheath blight, in this study, three series of β‐carboline urea, benzoylurea and benzoylthiourea derivatives were designed, synthesized and evaluated for in vitro and in vivo fungicidal activity against Rhizoctonia solani.

RESULTS

All these compounds (EC50: 0.131–1.227 mmol L−1) exhibited better fungicidal activity than harmine itself (EC50: 2.453 mmol L−1). Significantly, compound 17c (EC50: 0.131 mmol L−1) displayed the best efficacy in vitro and superior fungicidal activity compared with validamycin A (EC50: 0.397 mmol L−1). Moreover, the in vivo bioassay also indicated that compound 17c could be effective for the control of rice sheath blight.

CONCLUSION

Based on the bioassay result and quantitative structure–activity relationship (QSAR) information, structure modification in β‐carboline warrants further investigation and its benzoylurea derivative 17c, which showed the best fungicidal activities, could emerge as a potential fungicide against rice sheath blight. © 2018 Society of Chemical Industry
Differential accumulation of leucine and methionine in red and green pea aphids leads to different fecundity in response to nitrogen fertilization
Authors: Gao Jing , Guo Huijuan , Sun Yucheng , Ge Feng
Published: January 2018

BACKGROUND

Nitrogen fertilization affects plants directly and herbivorous insects indirectly. Although insect species and even genotypes are known to differ in their responses to nitrogen fertilization, the physiological and molecular mechanisms remain unclear. This study assessed the fecundity and related regulatory signaling pathways in the green and red morphs of pea aphid (Acyrthosiphon pisum) feeding on Medicago truncatula with and without nitrogen fertilization.

RESULTS

Nitrogen fertilization significantly increased foliar amino acid concentrations and consequently increased the concentrations of several individual essential amino acids in body tissue of the green morph. The increased concentration of Leu, Ile, Met and Val was consistent with enhanced biosynthesis of these amino acids in the endosymbiont Buchnera. Under nitrogen fertilization, Leu and Met accumulated in the green morph enhanced the target of rapamycin (TOR) signaling pathway, which consequently increased fecundity by promoting vitellogenin synthesis. In the red morph, however, nitrogen fertilization did not change the concentration of essential amino acids, TOR signaling or fecundity.

CONCLUSION

Specific amino acids accumulation and the nutrient transduction pathway in pea aphids are responsible for genotype‐specific fecundity in response to nitrogen fertilization, which could be used as potential target for pest control. © 2018 Society of Chemical Industry
Bufferless GaN‐Based MOSFETs Fabricated on GaN‐on‐Insulator Wafer
Authors: Won Chul‐Ho , Caulmilone Raphaël , Cristoloveanu Sorin , Im Ki‐Sik , Lee Jung‐Hee
Published: January 2018

Three types of bufferless GaN‐based FETs are fabricated on GaN‐on‐insulator (GaNOI) wafer: i) recessed‐gate AlGaN/GaN MOSFET with threshold voltage (Vth) of 4 V; ii) AlGaN/GaN nanowire gate‐all‐around (GAA) MOSFET with Vth of −2 V; and iii) GaN nanowire GAA‐MOSFET with Vth of 3.5 V. These devices are characterized and compared. The nanowire GAA‐MOSFET can be easily fabricated by simply removing buried oxide layer of GaNOI wafer. The recessed‐gate AlGaN/GaN MOSFET presents poor on‐current characteristic. On the other hand, the nanowire GAA‐MOSFETs show improved on‐current, reduced subthreshold swing (SS), good pinch‐off characteristics, and negligible current collapse phenomenon.
Phosphorus‐Related Complexes and Shallow Doping in Diamond
Authors: Alfieri Giovanni , Kranz Lukas , Mihaila Andrei
Published: January 2018

We present a theoretical study of phosphorus‐related complexes in diamond. Presently, phosphorus is the most shallow donor known in diamond, located at 0.56 eV below the conduction band edge. The study examines the possibility of co‐doping P with species of lower or higher electronegativity, in order to obtain a more shallow donor. The effects of electronegativity of the co‐dopant, on the energy position in the band gap of the studied complexes, are analyzed in the light of density functional theory calculations and of group theoretical analysis.
Flexible multistate models for interval‐censored data: Specification, estimation, and an application to ageing research
Authors: Machado Robson J. M. , van den Hout Ardo
Published: January 2018

Continuous‐time multistate survival models can be used to describe health‐related processes over time. In the presence of interval‐censored times for transitions between the living states, the likelihood is constructed using transition probabilities. Models can be specified using parametric or semiparametric shapes for the hazards. Semiparametric hazards can be fitted using P‐splines and penalised maximum likelihood estimation. This paper presents a method to estimate flexible multistate models that allow for parametric and semiparametric hazard specifications. The estimation is based on a scoring algorithm. The method is illustrated with data from the English Longitudinal Study of Ageing.
Chromogenic Photonic Crystal Sensors Enabled by Multistimuli‐Responsive Shape Memory Polymers
Authors: Leo Sin‐Yen , Zhang Wei , Zhang Yifan , Ni Yongliang , Jiang Helena , Jones Cory , Jiang Peng , Basile Vito , Taylor Curtis
Published: January 2018

Here novel chromogenic photonic crystal sensors based on smart shape memory polymers (SMPs) comprising polyester/polyether‐based urethane acrylates blended with tripropylene glycol diacrylate are reported, which exhibit nontraditional all‐room‐temperature shape memory (SM) effects. Stepwise recovery of the collapsed macropores with 350 nm diameter created by a “cold” programming process leads to easily perceived color changes that can be correlated with the concentrations of swelling analytes in complex, multicomponent nonswelling mixtures. High sensitivity (as low as 10 ppm) and unprecedented measurement range (from 10 ppm to 30 vol%) for analyzing ethanol in octane and gasoline have been demonstrated by leveraging colorimetric sensing in both liquid and gas phases. Proof‐of‐concept tests for specifically detecting ethanol in consumer medical and healthcare products have also been demonstrated. These sensors are inexpensive, reusable, durable, and readily deployable with mobile platforms for quantitative analysis. Additionally, theoretical modeling of solvent diffusion in macroporous SMPs provides fundamental insights into the mechanisms of nanoscopic SM recovery, which is a topic that has received little examination. These novel sensors are of great technological importance in a wide spectrum of applications ranging from environmental monitoring and workplace hazard identification to threat detection and process/product control in chemical, petroleum, and pharmaceutical industries.