Discovery of a seventh <Emphasis Type="Italic">Rpp</Emphasis> soybean rust resistance locus in soybean accession PI 605823

Key message

A novel Rpp gene from PI 605823 for resistance to Phakopsora pachyrhizi was mapped on chromosome 19.

Abstract

Soybean rust, caused by the obligate biotrophic fungal pathogen Phakopsora pachyrhizi Syd. & P. Syd, is a disease threat to soybean production in regions of the world with mild winters. Host plant resistance conditioned by resistance to P. pachyrhizi (Rpp) genes has been found in numerous soybean accessions, and at least 10 Rpp genes or alleles have been mapped to six genetic loci. Identifying additional disease-resistance genes will facilitate development of soybean cultivars with durable resistance. PI 605823, a plant introduction from Vietnam, was previously identified as resistant to US populations of P. pachyrhizi in greenhouse and field trials. In this study, bulked segregant analysis using an F₂ population derived from ‘Williams 82’ × PI 605823 identified a genomic region associated with resistance to P. pachyrhizi isolate GA12, which had been collected in the US State of Georgia in 2012. To further map the resistance locus, linkage mapping was carried out using single-nucleotide polymorphism markers and phenotypic data from greenhouse assays with an F_2:3 population derived from Williams 82 × PI 605823 and an F_4:5 population derived from ‘5601T’ × PI 605823. A novel resistance gene, Rpp7, was mapped to a 154-kb interval (Gm19: 39,462,291–39,616,643 Glyma.Wm82.a2) on chromosome 19 that is different from the genomic locations of any previously reported Rpp genes. This new gene could be incorporated into elite breeding lines to help provide more durable resistance to soybean rust.

     

Genetic analysis of net form net blotch resistance in barley lines CIho 5791 and Tifang against a global collection of <Emphasis Type="Italic">P. teres</Emphasis> f. <Emphasis Type="Italic">teres</Emphasis> isolates

Key message

A CIho 5791 × Tifang recombinant inbred mapping population was developed and used to identify major dominant resistance genes on barley chromosomes 6H and 3H in CI5791 and on 3H in Tifang.

Abstract

The barley line CIho 5791 confers high levels of resistance to Pyrenophora teres f. teres, causal agent of net form net blotch (NFNB), with few documented isolates overcoming this resistance. Tifang barley also harbors resistance to P. teres f. teres which was previously shown to localize to barley chromosome 3H. A CIho 5791 × Tifang F₆ recombinant inbred line (RIL) population was developed using single seed descent. The Illumina iSelect SNP platform was used to identify 2562 single nucleotide polymorphism (SNP) markers across the barley genome, resulting in seven linkage maps, one for each barley chromosome. The CIho 5791 × Tifang RIL population was evaluated for NFNB resistance using nine P. teres f. teres isolates collected globally. Tifang was resistant to four of the isolates tested whereas CIho 5791 was highly resistant to all nine isolates. QTL analysis indicated that the CIho 5791 resistance mapped to chromosome 6H whereas the Tifang resistance mapped to chromosome 3H. Additionally, CIho 5791 also harbored resistance to two Japanese isolates that mapped to a 3H region similar to that of Tifang. SNP markers and RILs harboring both 3H and 6H resistance will be useful in resistance breeding against NFNB.

     

Fine mapping of the chromosome 5B region carrying closely linked rust resistance genes <Emphasis Type="Italic">Yr47</Emphasis> and <Emphasis Type="Italic">Lr52</Emphasis> in wheat

Key message

Fine mapping of Yr47 and Lr52 in chromosome arm 5BS of wheat identified close linkage of the marker sun180 to both genes and its robustness for marker-assisted selection was demonstrated.

Abstract

The widely effective and genetically linked rust resistance genes Yr47 and Lr52 have previously been mapped in the short arm of chromosome 5B in two F₃ populations (Aus28183/Aus27229 and Aus28187/Aus27229). The Aus28183/Aus27229 F₃ population was advanced to generate an F₆ recombinant inbred line (RIL) population to identify markers closely linked with Yr47 and Lr52. Diverse genomic resources including flow-sorted chromosome survey sequence contigs representing the orthologous region in Brachypodium distachyon, the physical map of chromosome arm 5BS, expressed sequence tags (ESTs) located in the 5BS6-0.81-1.00 deletion bin and resistance gene analog contigs of chromosome arm 5BS were used to develop markers to saturate the target region. Selective genotyping was also performed using the iSelect 90 K Infinium wheat SNP assay. A set of SSR, STS, gene-based and SNP markers were developed and genotyped on the Aus28183/Aus27229 RIL population. Yr47 and Lr52 are genetically distinct genes that mapped 0.4 cM apart in the RIL population. The SSR marker sun180 co-segregated with Lr52 and mapped 0.4 cM distal to Yr47. In a high resolution mapping population of 600 F₂ genotypes Yr47 and Lr52 mapped 0.2 cM apart and marker sun180 was placed 0.4 cM distal to Lr52. The amplification of a different sun180 amplicon (195 bp) than that linked with Yr47 and Lr52 (200 bp) in 204 diverse wheat genotypes demonstrated its robustness for marker-assisted selection of these genes.

     

Bioactive compounds of <Emphasis Type="Italic">Aspergillus terreus</Emphasis>—F7, an endophytic fungus from <Emphasis Type="Italic">Hyptis suaveolens</Emphasis> (L.) Poit

The compounds terrein (1), butyrolactone I (2), and butyrolactone V (3) were isolated from the ethyl acetate extract (EtOAc) of the endophytic fungus Aspergillus terreus—F7 obtained from Hyptis suaveolens (L.) Poit. The extract and the compounds presented schistosomicidal activity against Schistosoma mansoni; at 100 µg/mL for EtOAc extract, 1297.3 µM for compound 1, 235.6 µM for compound 2, and 454.1 µM for compound 3, they killed 100% of the parasites after 72 h of treatment. Compounds 1, 2, and 3 exerted moderate leishmanicidal activity against Leishmania amazonensis (IC₅₀ ranged from 23.7 to 78.6 µM). At 235.6 and 227.0 µM, compounds 2 and 3, respectively, scavenged 95.92 and 95.12% of the DPPH radical (2,2-diphenyl-1-picryl-hydrazyl), respectively. Regarding the cytotoxicity against the breast tumor cell lines MDA-MB-231 and MCF-7, compound 2 gave IC₅₀ of 34.4 and 17.4 µM, respectively, while compound 3 afforded IC₅₀ of 22.2 and 31.9 µM, respectively. At 117.6 µM, compound 2 inhibited the growth of and killed the pathogen Escherichia coli (ATCC 25922). Compounds 1, 2, and 3 displayed low toxicity against the normal line of human lung fibroblasts (GM07492A cells), with IC₅₀ of 15.3?×?10³, 3.4?×?10³, and 5.8?×?10³ µM, respectively. This is the first report on (i) the in vitro schistosomicidal and leishmanicidal activities of the EtOAc extract of A. terreus—F7 and compounds 1, 2, and 3; and (ii) the antitumor activity of compounds 2 and 3 against MDA-MB-231 and MCF-7 cells.     

Differential alkaloid profile in <Emphasis Type="Italic">Uncaria tomentosa</Emphasis> micropropagated plantlets and root cultures

The alkaloids of Uncaria tomentosa micropropagated plantlets and root cultures were isolated and identified by NMR and mass spectrometry. Plantlets yielded pteropodine (1), isopteropodine (2), mitraphylline (3), isomitraphylline (4), uncarine F (5), speciophylline (6), rhynchophylline (7) and isorhynchophylline (8). In plantlets growing under continuous light, tetracyclic alkaloids 7 and 8 decreased from 20 ± 1.8 at 2 months to 2.2 ± 0.33 mg/g dry wt at 6 months, while the pentacyclic alkaloids 1–4 increased from 7.7 ± 1.4 to 15 ± 0.05 mg/g dry wt, supporting their biogenetic conversion. Micropropagated plantlets produced four times more alkaloids (27.6 ± 3.1 mg/g dry wt) than greenhouse plants. Plantlet roots yielded 3, 4, 8 and the glucoindole alkaloids 3α-dihydrocadambine (9) and dolichantoside (10), the last one not previously found in Uncaria.     

Characterization of morphology and resistance to <Emphasis Type="Italic">Blumeria graminis</Emphasis> of winter triticale monosomic addition lines with chromosome 2D of <Emphasis Type="Italic">Aegilops</Emphasis><Emphasis Type="Italic">tauschii</Emphasis>

Key message

Allocation of the chromosome 2D of Ae. tauschii in triticale background resulted in changes of its organization, what is related to varied expression of genes determining agronomically important traits.

Abstract

Monosomic alien addition lines (MAALs) are crucial for transfer of genes from wild relatives into cultivated varieties. This kind of genetic stocks is used for physical mapping of specific chromosomes and analyzing alien genes expression. The main aim of our study is to improve hexaploid triticale by transferring D-genome chromatin from Aegilops tauschii × Secale cereale (2n = 4x = 28, DDRR). In this paper, we demonstrate the molecular cytogenetics analysis and SSR markers screening combined with phenotype analysis and evaluation of powdery mildew infection of triticale monosomic addition lines carrying chromosome 2D of Ae. tauschii. We confirmed the inheritance of chromosome 2D from the BC₂F₄ to the BC₂F₆ generation of triticale hybrids. Moreover, we unveiled a high variable region on the short arm of chromosome 2D, where chromosome rearrangements were mapped. These events had direct influence on plant height of hybrids what might be connected with changes at Rht8 loci. We obtained 20 semi-dwarf plants of BC₂F₆ generation carrying 2D chromosome with the powdery mildew resistance, without changes in spike morphology, which can be used in the triticale breeding programs.

     

Four mononuclear platinum(II) complexes: synthesis,DNA/BSA binding,DNA cleavage and cytotoxicity

Four new platinum(II) complexes: Pt^II L1·H₂O (C1, H₂ L1 = C₂₀H₁₆N₂O₂), Pt^II L2Cl₂ (C2, L2 = C₂₂H₁₆N₂O₂), Pt^II L3Cl₂·H₂O (C3, L3 = C₂₀H₁₆N₂), Pt^II L4Cl₂·0.4H₂O (C4, L4 = C₁₈H₁₄N₄) have been synthesized and characterized by using various physico-chemical techniques. The binding interaction of the four platinum(II) complexes C1–C4 with calf thymus (CT)-DNA has been investigated by UV–Vis and fluorescence emission spectrometry. The apparent binding constant (K _app) values follow the order: C3 > C1 > C2 > C4. In addition, fluorescence spectrometry of bovine serum albumin (BSA) with the four platinum(II) complexes C1–C4 showed that the quenching mechanism might be a static quenching procedure. For C1–C4, the number of binding sites was about one for BSA and the binding constants follow the order: C3 (7.08 × 10⁵M^?1) > C1 (2.82 × 10⁵M^?1) > C2 (0.85 × 10⁵M^?1) > C4 (0.15 × 10⁵M^?1). With the single condition change such as absence of an external agent, the DNA cleavage abilities of C3 exhibit remarkable changes. In addition, the cytotoxicity of C3 in vitro on tumor cells lines (MCF-7, HepG2 and HT29) were examined by MTT and showed better antitumor effects on the tested cells.     

Effects of cycloheximide on photosynthetic abilities,reflectance spectra and fluorescence emission spectra in <Emphasis Type="Italic">Phyllostachys edulis</Emphasis>

Key message

CHX had remarkable inhibition on P. edulis photosynthesis, and the reflectance indexes and F ₆₈₅ / F ₇₃₅ had the potential value for quantifying the effects of antibiotics on trees.

Abstract

To reveal the effects of antibiotics on photosynthesis and provide help for remote sensing the influence of antibiotics on trees, we investigated the effects of cycloheximide (CHX) on Phyllostachys edulis. In CHX treatment, the photosynthetic pigment content in P. edulis was decreased markedly, which led to the increase in the reflectance spectra in visible region. CHX reduced the donor side and acceptor side of photosystem II (PSII), density of reaction centers, quantum production and electron transport in PSII, and raised the dissipation of absorbed light energy. Besides the dissipation, the absorbed light energy can be emitted as fluorescence with two main peaks in the red (685 nm) and far-red (735 nm) region, respectively. In 0.50 mM CHX treatment, a significant decline in the height and area of the peak at 685 nm might result from Chl loss reducing the light absorption and lower photochemical reaction in PSII. When fourth derivative analysis of fluorescence emission spectra was performed, the changes of the peaks at 718, 735 and 750 nm might result from the decline of absorbed solar radiation caused by the reduced pigment content and/or the damages to the PSI. In CHX treatment, a remarkable increase in intercellular CO₂ concentrations and light compensation point and decrease in light saturation point demonstrated that the CO₂ assimilation ability was decreased. Those results suggested that the photosynthesis in trees can be reduced after they were watered with wastewater containing CHX. The reflectance indexes and F ₆₈₅/F ₇₃₅ (H ₆₈₅/H ₇₃₅ and A ₆₈₅/A ₇₃₅) were markedly affected by CHX, demonstrating that they had the potential value for quantifying the effects of antibiotics on trees.

     

Allometric biomass,nutrient and carbon stock models for <Emphasis Type="Italic">Kandelia candel</Emphasis> of the Sundarbans,Bangladesh

Key message

Present study recommends DBH as independent variable of the derived allometric models and Biomass = a + b DBH ² has been selected for total above-ground biomass, nutrients and carbon stock.

Abstract

Kandelia candel (L.) Druce is a shrub to small tree of the Sundarbans mangrove forest of Bangladesh. The aim of the study was to derive the allometric models for estimating above-ground biomass, nutrient and carbon stock in K. candel. A total of eight linear models with 64 regression equations were tested to derive the allometric models for biomass of each part of plant; and nutrients and carbon stock in total above-ground biomass. The best fitted allometric models were selected by considering the values of R ², CV, R _mse, MS_error, S _a, S _b, F value, AICc and Furnival Index. The selected allometric models were Biomass = 0.014 DBH² + 0.03; √Biomass = 0.29 DBH ? 0.21; √Biomass = 0.66 √DBH ? 0.57; √Biomass = 1.19 √DBH ? 1.02; Biomass = 0.21 DBH² + 0.12 for leaves, branches, bark, stem without bark and total above-ground biomass, respectively. The selected allometric models for Nitrogen, Phosphorous, Potassium and Carbon stock in total above-ground biomass were N = 0.39 DBH² + 0.49, P = 0.77 DBH² + 0.14, K = 0.87 DBH² + 0.07 and C = 0.09 DBH² + 0.05, respectively. The derived allometric models have included DBH as a single independent variable, which may give quick and accurate estimation of the above-ground biomass, nutrient and carbon stock in this species. This information may also contribute to a broader study of nutrient cycling, nutrient budgeting and carbon sequestration of the studied forest.

     

Development of <Emphasis Type="Italic">Brassica oleracea</Emphasis>-<Emphasis Type="Italic">nigra</Emphasis> monosomic alien addition lines: genotypic,cytological and morphological analyses

Key message

We report the development and characterization of Brassica oleracea - nigra monosomic alien addition lines (MAALs) to dissect the Brassica B genome.

Abstract

Brassica nigra (2n = 16, BB) represents the diploid Brassica B genome which carries many useful genes and traits for breeding but received limited studies. To dissect the B genome from B. nigra, the triploid F₁ hybrid (2n = 26, CCB) obtained previously from the cross B. oleracea var. alboglabra (2n = 18, CC) × B. nigra was used as the maternal parent and backcrossed successively to parental B. oleracea. The progenies in BC₁ to BC₃ generations were analyzed by the methods of FISH and SSR markers to screen the monosomic alien addition lines (MAALs) with each of eight different B-genome chromosomes added to C genome (2n = 19, CC + 1B_1?8), and seven different MAALs were established, except for the one with chromosome B2 which existed in one triple addition. Most of these MAALs were distinguishable morphologically from each other, as they expressed the characters from B. nigra differently and at variable extents. The alien chromosome remained unpaired as a univalent in 86.24% pollen mother cells at diakinesis or metaphase I, and formed a trivalent with two C-genome chromosomes in 13.76% cells. Transmission frequency of all the added chromosomes was far higher through the ovules (averagely 14.40%) than the pollen (2.64%). The B1, B4 and B5 chromosomes were transmitted by female at much higher rates (22.38–30.00%) than the other four (B3, B6, B7, B8) (5.04–8.42%). The MAALs should be valuable for exploiting the genome structure and evolution of B. nigra.

     

Molecular mapping and candidate gene analysis of a new epicuticular wax locus in sorghum (<Emphasis Type="Italic">Sorghum bicolor</Emphasis> L. Moench)

Key message

A new epicuticular wax (bloom) locus has been identified and fine mapped to the 207.89 kb genomic region on chromosome 1. A putative candidate gene, Sobic.001G269200, annotated as GDSL-like lipase/acylhydrolase, is proposed as the most probable candidate gene involved in bloom synthesis/deposition.

Abstract

Deposition of epicuticular wax on plant aerial surface is one strategy that plants adapt to reduce non-transpiration water loss. Epicuticular wax (bloom)-less mutants in sorghum with their glossy phenotypes exhibit changes in the accumulation of epicuticular wax on leaf and culm surfaces. We report molecular mapping of a new sorghum locus, bloomless mutant (bm39), involved in epicuticular wax biosynthesis in sorghum. Inheritance studies involving a profusely bloom parent (BTx623) and a spontaneous bloomless mutant (RS647) indicated that the parents differed in a single gene for bloom synthesis. Bloomless was recessive to bloom deposition. Genetic mapping involving F₂ and F₇ mapping populations in diverse genetic backgrounds (BTx623 × RS647; 296A × RS647 and 27A × RS647) identified and validated the map location of bm39 to a region of 207.89 kb on chromosome 1. SSR markers, Sblm13 and Sblm16, flanked the bm39 locus to a map interval of 0.3 cM on either side. Nine candidate genes were identified, of which Sobic.001G269200 annotated for GDSL-like lipase/acylhydrolase is the most likely gene associated with epicuticular wax deposition. Gene expression analysis in parents, isogenic lines and sets of near isogenic lines also confirmed the reduced expression of the putative candidate gene. The study opens possibilities for a detailed molecular analysis of the gene, its role in epicuticular wax synthesis and deposition, and may help to understand its function in moisture stress tolerance and insect and pathogen resistance in sorghum.

     

Tyrosinase and catechol oxidase activity of copper(I) complexes supported by imidazole-based ligands: structure–reactivity correlations

Four new imidazole-based ligands, 4-((1H-imidazol-4-yl)methyl)-2-phenyl-4,5-dihydrooxyzole (L _OL 1), 4-((1H-imidazol-4-yl)methyl)-2-(tert-butyl)-4,5-dihydrooxyzole (L _OL 2), 4-((1H-imidazol-4-yl)methyl)-2-methyl-4,5-dihydrooxyzole (L _OL 3), and N-(2,2-dimethylpropylidene)-2-(1-trityl-1H-imidazol-4-yl-)ethyl amine (L _imz 1), have been synthesized. The corresponding copper(I) complexes [Cu(I)(L _OL 1)(CH₃CN)]PF₆ (CuL _OL 1), [Cu(I)(L _OL 2)(CH₃CN)]PF₆ (CuL _OL 2), [Cu(I)(L _OL 3)(CH₃CN)]PF₆ (CuL _OL 3), [Cu(I)(L _imz 1)(CH₃CN)₂]PF₆ (CuL _imz 1) as well as the Cu(I) complex derived from the known ligand bis(1-methylimidazol-2-yl)methane (BIMZ), [Cu(I)(BIMZ)(CH₃CN)]PF₆ (CuBIMZ), are screened as catalysts for the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC-H₂) to 3,5-di-tert-butylquinone (3,5-DTBQ). The primary reaction product of these oxidations is 3,5-di-tert-butylsemiquinone (3,5-DTBSQ) which slowly converts to 3,5-DTBQ. Saturation kinetic studies reveal a trend of catalytic activity in the order CuL _OL 3 ≈ CuL _OL 1 > CuBIMZ > CuL _OL 2 > CuL _imz 1. Additionally, the catalytic activity of the copper(I) complexes towards the oxygenation of monophenols is investigated. As substrates 2,4-di-tert-butylphenol (2,4-DTBP-H), 3-tert-butylphenol (3-TBP-H), 4-methoxyphenol (4-MeOP-H), N-acetyl-l-tyrosine ethyl ester monohydrate (NATEE) and 8-hydroxyquinoline are employed. The oxygenation products are identified and characterized with the help of UV/Vis and NMR spectroscopy, mass spectrometry, and fluorescence measurements. Whereas the copper complexes with ligands containing combinations of imidazole and imine functions or two imidazole units (CuL _imz 1 and CuBIMZ) are found to exhibit catalytic tyrosinase activity, the systems with ligands containing oxazoline just mediate a stoichiometric conversion. Correlations between the structures of the complexes and their reactivities are discussed.     

Synthesis and evaluation of copper(II) complexes with isoniazid-derived hydrazones as anticancer and antitubercular agents

In this study, the N,N,O metal chelator 2-pyridinecarboxaldehydeisonicotinoyl hydrazone (HPCIH, 1) and its derivatives 2-acetylpyridine-(HAPIH 2), 2-pyridineformamide-(HPAmIH, 3) and pyrazineformamide-(HPzAmIH, 4) were employed in the synthesis of four copper(II) complexes, [Cu(HPCIH)Cl₂]·0.4H₂O (5), [Cu(HAPIH)Cl₂]·1.25H₂O (6), [Cu(HPAmIH)Cl₂]·H₂O (7) and [Cu(HPzAmIH)Cl₂]·1.25H₂O (8). The compounds were assayed for their action toward Mycobacterium tuberculosis H37Rv ATCC 27294 strain and the human tumor cell lines OVCAR-8 (ovarian cancer), SF-295 (glioblastoma multiforme) and HCT-116 (colon adenocarcinoma). All copper(II) complexes were more effective in reducing growth of HCT-116 and SF-295 cells than the respective free hydrazones at 5 µg/mL, whereas only complex 7 was more cytotoxic toward OVCAR-8 lines than its ligand HPAmIH. 6 proved to be cytotoxic at submicromolar doses, whose IC₅₀ values (0.39–0.86 µM) are similar to those ones found for doxorubicin (0.23–0.43 µM). Complexes 5 and 6 displayed high activity against M. tuberculosis (MIC = 0.85 and 1.58 µM, respectively), as compared with isoniazid (MIC = 2.27 µM), which suggests the compounds are attractive candidates as antitubercular drugs.     

Fine mapping of QTL <Emphasis Type="Italic">qCTB10</Emphasis>-<Emphasis Type="Italic">2</Emphasis> that confers cold tolerance at the booting stage in rice

Key message

The QTL qCTB10 - 2 controlling cold tolerance at the booting stage in rice was delimited to a 132.5 kb region containing 17 candidate genes and 4 genes were cold-inducible.

Abstract

Low temperature at the booting stage is a major abiotic stress-limiting rice production. Although some QTL for cold tolerance in rice have been reported, fine mapping of those QTL effective at the booting stage is few. Here, the near-isogenic line ZL31-2, selected from a BC₇F₂ population derived from a cross between cold-tolerant variety Kunmingxiaobaigu (KMXBG) and the cold-sensitive variety Towada, was used to map a QTL on chromosome 10 for cold tolerance at the booting stage. Using BC₇F₃ and BC₇F₄ populations, we firstly confirmed qCTB10-2 and gained confidence that it could be fine mapped. QTL qCTB10-2 explained 13.9 and 15.9% of the phenotypic variances in those two generations, respectively. Using homozygous recombinants screened from larger BC₇F₄ and BC₇F₅ populations, qCTB10-2 was delimited to a 132.5 kb region between markers RM25121 and MM0568. 17 putative predicted genes were located in the region and only 5 were predicted to encode expressed proteins. Expression patterns of these five genes demonstrated that, except for constant expression of LOC_Os10g11820, LOC_Os10g11730, LOC_Os10g11770, and LOC_Os10g11810 were highly induced by cold stress in ZL31-2 compared to Towada, while LOC_Os10g11750 showed little difference. Our results provide a basis for identifying the genes underlying qCTB10-2 and indicate that markers linked to the qCTB10-2 locus can be used to improve the cold tolerance of rice at the booting stage by marker-assisted selection.

     

Dietary Supplementation of Selenium-Enriched Probiotics Enhances Meat Quality of Broiler Chickens (<Emphasis Type="Italic">Gallus gallus domesticus</Emphasis>) Raised Under High Ambient Temperature

We investigated the effects of selenium-enriched probiotics (SP) on broiler meat quality under high ambient temperature and explore their underlying mechanisms. A total of 200 1-day-old male broiler chicks (Ross 308) were randomly allotted to four treatment groups, each with five replicates, in groups of ten birds. These birds were fed a corn-soybean basal diet (C), a basal diet plus probiotics supplementation (P), a basal diet plus Se supplementation in the form of sodium selenite (SS, 0.30 mg Se/kg), and a basal diet with the addition of selenium-enriched probiotics (SP, 0.30 mg Se/kg). The experiment lasted for 42 days. The birds were sacrificed by cervical dislocation, and the breast muscles were removed for further process. Our results showed that SP diet significantly increased (p < 0.05) the physical (pH, colors, water holding capacity, drip loss, shear force) and sensory characteristics of breast meat. All P, SS, and SP supplementation enhanced the antioxidant system by increasing (p < 0.05) the Se concentrations, glutathione (GSH) levels, activities of glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) whereas decreasing (p < 0.05) malondialdehyde (MDA) levels, with SP being higher than P and SS. Moreover, SP diet significantly upregulated (p < 0.05) the mRNA levels of glutathione peroxidase genes (GPx1, GPx4) while it downregulated heat stress biomarkers such as heat shock protein (HSP) 70 as compared to C, P, and SS diets. In conclusion, our findings suggest that SP may function as beneficial nutritive supplement that is capable of improving meat quality during the summer season.     

Aromaticity of graphene nanoflakes in a new way: fragment analysis by combination of the nucleus-independent chemical shifts and the anisotropy of current induced density

A graphene nanoflake (GNF) is a polycyclic aromatic hydrocarbon (PAH) with a huge two-dimensional π-conjugated carbon material in which a central benzene ring is surrounded by identical benzene-type rings through infinite alternant method. In this paper, we explore the structure-aromaticity relationship of the GNFs and the GNFs with hollow sites (GNFHs) by combining the nucleus-independent chemical shifts (NICS) with the anisotropy of the current induced density (ACID). Firstly, the benzene is a typical aromatic molecule (NICS = ?9.671 ppm), GNFs 1-6 is darned with benzene and the corresponding GNFHs 1′-6′. Secondly, the NICS values of GNFs 1-6 alternately vary: ?1.214 (1) > ?13.847 (2) < ?2.662 (3) > ?14.530 (4) < ?3.932 (5) > ?13.978 (6) ppm, the GNFs (2, 4, 6) with even fragments of annulene have larger aromaticity than that of GNFs (1, 3, 5) with odd fragments of annulene. Significantly, the NICS values of GNFs 1-6 can also be fragment analyzed by the NICS values and ACID of benzene and corresponding GNFHs 1′-6′. The NICS values for GNFs (2, 4, 6) can be roughly estimated by the NICS value of benzene minus the NICS value of the GNFHs (2′, 4′, 6′), respectively. The NICS values for GNFs (1, 3, 5) can be roughly estimated by the NICS value of the GNFHs (1′, 3′, 5′) minus the NICS value of benzene, respectively. We hope that the present work can provide a simple and reliable method for the rational design of the GNF with aromaticity, which may be used to understand the origin of the graphene nanoflake aromatic properties.     

A mechanistic investigation on the formation and rearrangement of silaspiropentane: A theoretical study

The formation of silaspiropentane from addition of singlet silacyclopropylidene 1 and silacyclopropylidenoid 8 to ethylene has been investigated separately at the B3LYP, X3LYP, WB97XD, and M05–2X theories using the 6–31+G(d,p) basis set. The silacycloproylidenoid addition follows a stepwise route. In contrast, a concerted mechanism occurs for silacyclopropylidene addition. Moreover, the intramolecular rearrangements of silaspiropentane 9 to methylenesilacyclobutane 11 and 2-silaallene?+?ethylene 12 have been studied extensively. The required energy barrier for the isomerization of 9 to 10 was determined to be 44.0 kcal mol^?1 at the B3LYP/6–31+G(d,p) level. After formation of 10, the rearrangement to methylenesilacyclobutane 12 is highly exergonic by ?15.9 kcal mol^?1, which makes this reaction promising. However, the conversion of 9 to 11 is calculated to be quite endergonic, by 26.5 kcal mol^?1.     

How are anatomical and hydraulic features of the mangroves <Emphasis Type="Italic">Avicennia marina</Emphasis> and <Emphasis Type="Italic">Rhizophora mucronata</Emphasis> influenced by siltation?

Key message

This article provides significant data in the debate on whether siltation might have a negative impact on the hydraulic functioning of two widespread mangrove tree species Avicennia marina and Rhizophora mucronata.

Abstract

Elevated sediment addition, or siltation, within mangrove ecosystems is considered as being negative for trees and saplings, resulting in stress and higher mortality rates. However, little is known about how siltation influences the hydraulic functioning of mangrove trees. Comparing two mangrove tree species (Avicennia marina Vierh. Forsk. and Rhizophora mucronata Lam.) from low and high-siltation plots led to the detection of anatomical and morphological differences and tendencies. Adaptations to high siltation were found to be either mutual among both species, e.g., significant smaller single leaf area (p _A.marina  = 0.058, F1.38 = 3.8; p _R.mucronata  = 0.005, F1.38 = 8.7; n = 20 × 20) and a tendency towards smaller stomatal areas (p _A.marina  = 0.131, F1.8 = 2.8; p _R.mucronata  = 0.185, F1.8 = 2.1, n = 5 × 60), or species-specific trends for A. marina, such as higher phloem band/growth layer ratios (p = 0.101, F1.8 = 3.4, n = 5 × 3) and stomatal density (p = 0.052, F1.8 = 5.2, n = 5 × 4). All adaptations seemingly contributed to a comparable hydraulic conductivity independent of the degree of siltation. These findings indicate that silted trees level off fluctuations in their hydraulic performance as a survival mechanism to cope with this less favourable environment. Most of the trees’ structural adaptations to cope with siltation are similar to known drought stress-imposed adaptations.

     

Identification of a locus in maize controlling response to a host-selective toxin derived from <Emphasis Type="Italic">Cochliobolus heterostrophus</Emphasis>, causal agent of southern leaf blight

Key Message

A host-selective, proteinaceous maize toxin was identified from the culture filtrate of the maize pathogen Cochliobolus heterostrophus. A dominant gene for toxin susceptibility was identified on maize chromosome 4.

Abstract

A toxic activity was identified from the culture filtrate (CF) of the fungus Cochliobolus heterostrophus, causal agent of the maize disease southern leaf blight (SLB) with differential toxicity on maize lines. Two independent mapping populations; a 113-line recombinant inbred line population and a 258-line association population, were used to map loci associated with sensitivity to the CF at the seedling stage. A major QTL on chromosome 4 was identified at the same locus using both populations. Mapping in the association population defined a 400 kb region that contained the sensitivity locus. By comparing CF-sensitivity of the parents of the RIL population with that of the F₁ progeny, we determined that the sensitivity allele was dominant. No relationship was observed between CF-sensitivity in seedlings and SLB susceptibility in mature plants; however, a significant correlation (??0.58) was observed between SLB susceptibility and CF-sensitivity in seedlings. The activity of the CF was light-dependent and was sensitive to pronase, indicating that the toxin was proteinaceous.