High molecular weight glutenin subunits in some durum wheat cultivars investigated by means of mass spectrometric techniques

The primary structures of high molecular weight glutenin subunits (HMW-GS) of 5 Triticum durum Desf. cultivars (Simeto, Svevo, Duilio, Bronte, and Sant'Agata), largely cultivated in the south of Italy, and of 13 populations of the old spring Sicilian durum wheat landrace Timilia (Triticum durum Desf.) (accession nos. 1, 2, 3, 4, 7, 8, 9, 13, 14, 15, SG1, SG2, and SG3) were investigated using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) and reversed-phase high performance liquid chromatography/nanoelectrospray ionization mass spectrometry (RP-HPLC/nESI-MS/MS). M(r) of the intact proteins determined by MALDI mass spectrometry showed that all the 13 populations of Timilia contained the same two HMW-GS with 75.2 kDa and 86.4 kDa, whereas the other durum wheat cultivars showed the presence of the expected HMW-GS 1By8 and 1Bx7 at 75.1 kDa and 83.1 kDa, respectively. By MALDI mass spectrometry of the tryptic digestion peptides of the isolated HMW-GS of Timilia, the 1Bx and 1By subunits were identified as the NCBInr Acc. No AAQ93629, and AAQ93633, respectively. Sequence verification for HMW-GS 1Bx and 1By both in Simeto and Timilia was obtained by MALDI mass mapping and HPLC/nESI-MSMS of the tryptic peptides. The Bx subunit of Timila presents a sequence similarity of 96% with respect to Simeto, with differences in the insertion of 3 peptides of 5, 9, and 15 amino acids, for a total insertion of 29 amino acids and 25 amino acid substitutions. These differences in the amino acidic sequence account for the determined Δm of 3294 Da between the M(r) of the 1Bx subunits in Timilia and Simeto. Sequence alignment between the two By subunits shows 10 amino acid substitutions and is consistent with the Δm of 148 Da found in the MALDI mass spectra of the intact subunits.     

Transmission electron microscopy for characterization of acrosomal damage after Percoll gradient centrifugation of cryopreserved bovine spermatozoa

The objective of this study was to characterize acrosomal ultrastructure following discontinuous Percoll gradient centrifugation of cryopreserved bovine sperm. Semen was collected from six bulls of different breeds and three ejaculates per bull were evaluated. Frozen semen samples were thawed and the acrosomal region of sperm cells was evaluated by transmission electron microscopy (TEM) before (n = 18) and after (n = 18) Percoll centrifugation. The evaluation of 20 sperm heads from each of the 36 samples analyzed ensured that a large number of cells were investigated. The data were subjected to analysis of variance at a level of significance of 5%. Percoll centrifugation reduced the percentage of sperm exhibiting normal acrosomes (from 61.77 to 30.24%), reduced the percentage of sperm presenting atypical acrosome reactions (from 28.38 to 4.84%) and increased the percentage of sperm exhibiting damage in the acrosome (from 6.14 to 64.26%). The percentage of sperm with typical acrosome reactions was not significantly different before (3.70%) and after (0.67%) centrifugation. TEM distinguished four different types of acrosomal status and enabled ultrastructural characterization of acrosomal injuries. The percentage of sperm exhibiting normal acrosomes decreased and damage in the acrosome was the most frequent acrosomal injury with the Percoll gradient centrifugation protocol utilized.     

FTIR-ATR-based prediction and modelling of lignin and energy contents reveals independent intra-specific variation of these traits in bioenergy poplars

Background  

There is an increasing demand for renewable resources to replace fossil fuels. However, different applications such as the production of secondary biofuels or combustion for energy production require different wood properties. Therefore, high-throughput methods are needed for rapid screening of wood in large scale samples, e.g., to evaluate the outcome of tree breeding or genetic engineering. In this study, we investigated the intra-specific variability of lignin and energy contents in extractive-free wood of hybrid poplar progenies (Populus trichocarpa × deltoides) and tested if the range was sufficient for the development of quantitative prediction models based on Fourier transform infrared spectroscopy (FTIR). Since lignin is a major energy-bearing compound, we expected that the energy content of wood would be positively correlated with the lignin content.     

A simple and efficient method for isolating small RNAs from different plant species

Background  

Small RNAs emerged over the last decade as key regulators in diverse biological processes in eukaryotic organisms. To identify and study small RNAs, good and efficient protocols are necessary to isolate them, which sometimes may be challenging due to the composition of specific tissues of certain plant species. Here we describe a simple and efficient method to isolate small RNAs from different plant species.     

Diofenolan: a novel insect growth regulator in common citrus butterfly, <Emphasis Type="Italic">Papilio demoleus</Emphasis>

Penultimate and last instar larvae of the common citrus swallowtail butterfly, Papilio demoleus L. (Papilionidae: Lepidoptera), were treated with different doses of a novel juvenoid, diofenolan. Several deformities were observed as a result of topical administration of diofenolan which include delay in larval–larval and larval–pupal ecdysis, ecdysial failure, mortality, severe reduction in pupation, deformed pupae and complete inhibition of adult emergence. The juvenoid diofenolan severely hampers the normal growth, development and metamorphosis of P. demoleus and can be incorporated into integrated pest management programs for successful control of this important pest of citrus all over the world.     

Note on <Emphasis Type="Italic">Wahlgreniella nervata</Emphasis> (Gillette, 1908) (Hemiptera: Aphididae): a new pest of Damask rose in Turkey

Alate viviparous females of Wahlgreniella nervata (Gillette) were found on a Damask rose (Rosa damascena Mill.) plantation in Isparta Province, Turkey. The aphid is recorded for the first time from Turkey. Besides, Damask rose is a new host for this species. Brief information about this aphid including a key to the alate females of aphid species known to infest Damask rose in Turkey is provided.     

Resistance of <Emphasis Type="BoldItalic">Spodoptera exigua</Emphasis> to ten insecticides in Shandong,China

Spodoptera exigua (Hübner) collected from three regions (two scallion-producing regions and one ginger-producing region) in Shandong, China and a laboratory colony of Wuhan (WHLC) were evaluated for their susceptibilities to ten insecticides (emamectin benzoate, chlorfenapyr, indoxacarb, spinosyn, tebufenozide, methoxyfenozide, chlorfluazuron, beta-cypermethrin, chlorpyrifos and methomyl) in 2008, 2009 and 2010 using a leaf-dip bioassay method. The results indicate that the resistance ratios of S. exigua to newer insecticides such as emamectin benzoate, chlorfenapyr and indoxacarb were all below 20-fold, with no obvious change in all 3 years. S. exigua exhibits moderate resistance to spinosyn, and its resistance ratios increased from 1.98–5.31-fold in 2008 to 14.31–64.20-fold in 2010 from three regions as compared with WHLC. S. exigua showed moderate to high resistance to insect growth regulators such as tebufenozide, methoxyfenozide, chlorfluazuron in 2008, 2009 and 2010, in which resistance to chlorfluazuron was rapidly increased from 31.49–88.19-fold in 2008 to 1184.39–2789.67-fold in 2010. Resistance of S. exigua to beta-cypermethrin and chlorpyrifos varied greatly among the three regions, ranging from 95.31–437.97-fold and 25.05–40.64-fold in 2008, 951.81–1304.40-fold and 44.91–186.33-fold in 2009, to 27.27–1095.31-fold and 19.12–267.98-fold in 2010. In contrast, S. exigua showed low resistance to methomyl, and the resistance ratio was below 5-fold in 3 years. There are several reasons accounting for varying degrees of resistance, including selection pressure, cropping structure and migration, in which the migration of S. exigua may play an important role.     

A molecular mechanism of resistance to streptomycin in <Emphasis Type="Italic">Xanthomonas oryzae</Emphasis> pv. <Emphasis Type="Italic">oryzicola</Emphasis>

Xanthomonas oryzae pv. oryzicola, the causal agent of rice leaf streak disease, was found to be sensitive to streptomycin (an aminocyclitol glycoside antibiotic), by inhibition of protein synthesis resulting from interference with translational proofreading. This study aimed to determine the molecular resistance mechanism of X. oryzae pv. oryzicola to streptomycin. Seven streptomycin-resistant mutants were obtained by UV induction or streptomycin selection. These mutants can grow at 100 μg ml⁻¹ of streptomycin while the wild-type strain (RS105) cannot grow at 5 μg ml⁻¹. Sequencing indicated that the rpsL gene encoding ribosomal protein S12 has 375 bp encoding 125 amino acid residues. In all resistant strains, a mutation in which AAG was substituted for AGG (Lys→Arg) occurred either at codon 43 or 88. Two plasmids, pUFRRS and pUFRRX, were constructed by ligating the rpsL gene into the cosmid pUFR034. The plasmids pUFRRS and pUFRRX containing the Lys→Arg mutation of the rpsL gene conferred streptomycin resistance to the sensitive wild-type strain by electroporation. Both transformants, RS1 and RS2, could grow in the medium containing 50 μg ml⁻¹ of streptomycin. A mutation at codon 43 or 88 in rpsL can result in resistance of Xanthomonas oryzae pv. oryzicola to streptomycin.