Preliminary Study on the Activity of Phycobiliproteins against Botrytis cinerea

Phycobiliproteins (PBPs) are proteins of cyanobacteria and some algae such as rhodophytes. They have antimicrobial, antiviral, antitumor, antioxidative, and anti-inflammatory activity at the human level, but there is a lack of knowledge on their antifungal activity against plant pathogens. We studied the activity of PBPs extracted from Arthrospira platensis and Hydropuntia cornea against Botrytis cinerea, one of the most important worldwide plant-pathogenic fungi. PBPs were characterized by using FT-IR and FT-Raman in order to investigate their structures. Their spectra differed in the relative composition in the amide bands, which were particularly strong in A. platensis. PBP activity was tested on tomato fruits against gray mold disease, fungal growth, and spore germination at different concentrations (0.3, 0.6, 1.2, 2.4, and 4.8 mg/mL). Both PBPs reduced fruit gray mold disease. A linear dose–response relationship was observed for both PBPs against disease incidence and H. cornea against disease severity. Pathogen mycelial growth and spore germination were reduced significantly by both PBPs. In conclusion, PBPs have the potential for being also considered as natural compounds for the control of fungal plant pathogens in sustainable agriculture.     

Changes in the histochemical properties and meat quality traits of porcine muscles during the growing-finishing period as affected by feed restriction, slaughter age, or slaughter weight

In this study, the degree of contractile and metabolic development of myofibers in porcine LM, rectus femoris (RF), and dark and light portions of the semitendinosus (STD and STL, respectively) was determined, and their impact on meat quality was compared at the same age but different BW (trial 1) or at a given BW but different age (trial 2) in 48 Swiss Large White barrows from 12 litters after the growing and finishing period. The barrows had ad libitum (A) or restricted (R, 80% of A) feed access. In trial 1, at 113 and 154 d of age, 6 barrows in treatment A (62.1 and 99.5 kg of BW, respectively) and 6 siblings in treatment R (51.0 and 86.6 kg of BW, respectively) were slaughtered. In trial 2, a similar protocol was used except that the barrows were slaughtered at 61.3 (104 or 119 d of age, respectively) or 101.3 kg of BW (145 or 167 d of age, respectively). Muscle fibers were stained and classified as slow oxidative (SO), fast oxidative-glycolytic (FOG), or fast glycolytic (FG), and fiber area and distribution were determined. At 113 and 154 d of age, R barrows had smaller (P < or = 0.04) SO fibers in the LM, STD, and STL, smaller (P < 0.01) FOG fibers in the STL, smaller (P = 0.03) FG fibers in the LM, and smaller (P < or = 0.04) overall mean area in the LM, STD, and STL. In the STL and RF, R barrows had fewer (P < or = 0.06) FG and more (P < or = 0.08) FOG fibers than A barrows at 113 and 154 d of age. Except for smaller FOG fibers in the STD of R compared with A barrows slaughtered at the same BW, the myofiber size did not differ (P > or = 0.11). However, the LM tended to have fewer (P = 0.06) SO and more (P < 0.01) FG fibers, and the STD had more (P < 0.01) FOG fibers in R barrows. Regardless of whether R barrows were slaughtered at the same age or the same BW as the A barrows, shear force values and cooking losses were greater (P < or = 0.08) in the STD and STL of R barrows. These findings revealed that myofiber hypertrophy was impaired by feed restriction in barrows compared at the same age, but differences in myofiber size vanished at the same BW. By contrast, restricted nutrient supply affected myofiber maturation depending on the age and BW, but the impact differed between muscles. The absence of changes in myofiber type distribution among the younger-lighter and older-heavier barrows indicated that myofiber maturation was already completed in the younger-lighter barrows. Although changes in meat quality traits were affected by the feeding regimen, they were not related to myofiber characteristics.     

Genetic improvement in wheat yield and associated traits. A re-examination of previous results and the latest trends

Two field experiments were carried out with seven wheat cultivars (three of them, including a commercial hybrid, released during the last 10 years) representing different eras of plant breeding, to evaluate genetic improvement over the last century in grain yield, height, biomass, harvest index and grain yield components. Plots were fertilized and irrigated, and lodging and diseases were prevented. Main culm height was negatively correlated with the year of release of the cultivars, probably as a consequence of selection for increased lodging resistance. There was no significant association between total above-ground biomass and year of release of the cultivars. On the other hand, grain yield increased as newer cultivars were released. Results indicate that during recent years harvest index has been kept as the main attribute responsible for increases in grain yield. In general, number of grains/m² was associated with increases in grain yield during the century. However, the newest cultivars showed an increased grain weight. In both growing seasons, cultivars released before 1980 showed a trend towards reduced grain weight, but cultivars released after 1987 had a similar number of grains per m² with a higher grain weight than their predecessors. This was probably because the most modern cultivars have a longer grain-filling duration with a similar length of growth cycle.     

Equivalent effects of snake PLA2 neurotoxins and lysophospholipid-fatty acid mixtures

Snake presynaptic phospholipase A2 neurotoxins (SPANs) paralyze the neuromuscular junction (NMJ). Upon intoxication, the NMJ enlarges and has a reduced content of synaptic vesicles, and primary neuronal cultures show synaptic swelling with surface exposure of the lumenal domain of the synaptic vesicle protein synaptotagmin I. Concomitantly, these neurotoxins induce exocytosis of neurotransmitters. We found that an equimolar mixture of lysophospholipids and fatty acids closely mimics all of the biological effects of SPANs. These results draw attention to the possible role of local lipid changes in synaptic vesicle release and provide new tools for the study of exocytosis.     

Radar soundings of the subsurface of Mars

The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick.     

Effect of commercial lignosulfonate-humate on Zea mays L. metabolism

Lignosulfonate-humate a and lignosulfonate-humate b, derived by an industrial process from lignin, were studied chemically and biologically, and their effects on maize metabolism compared with the responses induced by humic substances obtained from leonardite. Lignosulfonate-humate a and lignosulfonate-humate b elicited hormonelike activity and leonardite displayed giberellin properties. To improve our understanding of their biological action, lignosulfonate-humate a, lignosulfonate-humate b and leonardite were supplied to maize plants and their effect was studied on growth, nitrogen metabolism and photosynthesis. All products increased root and leaf growth. Glutamine-synthetase, glutamate-synthase enzyme activities and protein content were all increased. The treatments also increased chlorophyll content, glucose, fructose and rubisco enzyme activity, suggesting a positive role of lignosulfonate-humate a, lignosulfonate-humate b and leonardite in the photosynthetic process. In addition, an increase in phenol content was observed. In light of these results, being environmentally friendly products, lignosulfonate-humate a and lignosulfonate-humate b could be used to increase crop yield.     

Impaired control of IRES-mediated translation in X-linked dyskeratosis congenita

The DKC1 gene encodes a pseudouridine synthase that modifies ribosomal RNA (rRNA). DKC1 is mutated in people with X-linked dyskeratosis congenita (X-DC), a disease characterized by bone marrow failure, skin abnormalities, and increased susceptibility to cancer. How alterations in ribosome modification might lead to cancer and other features of the disease remains unknown. Using an unbiased proteomics strategy, we discovered a specific defect in IRES (internal ribosome entry site)-dependent translation in Dkc1(m) mice and in cells from X-DC patients. This defect results in impaired translation of messenger RNAs containing IRES elements, including those encoding the tumor suppressor p27(Kip1) and the antiapoptotic factors Bcl-xL and XIAP (X-linked Inhibitor of Apoptosis Protein). Moreover, Dkc1(m) ribosomes were unable to direct translation from IRES elements present in viral messenger RNAs. These findings reveal a potential mechanism by which defective ribosome activity leads to disease and cancer.     

The mtDNA legacy of the Levantine early Upper Palaeolithic in Africa

Sequencing of 81 entire human mitochondrial DNAs (mtDNAs) belonging to haplogroups M1 and U6 reveals that these predominantly North African clades arose in southwestern Asia and moved together to Africa about 40,000 to 45,000 years ago. Their arrival temporally overlaps with the event(s) that led to the peopling of Europe by modern humans and was most likely the result of the same change in climate conditions that allowed humans to enter the Levant, opening the way to the colonization of both Europe and North Africa. Thus, the early Upper Palaeolithic population(s) carrying M1 and U6 did not return to Africa along the southern coastal route of the "out of Africa" exit, but from the Mediterranean area; and the North African Dabban and European Aurignacian industries derived from a common Levantine source.     

TRAP molecular markers as a system for saturation of the genetic map of durum wheat

Target region amplification polymorphism (TRAP) is a relatively new PCR-based technique that detects large numbers of loci in a single reaction without extensive pre-PCR processing of samples. The aim of this study was to integrate TRAP markers in an EST-derived SSR linkage map of a RIL mapping population from the cross of the durum wheat cultivars Ciccio and Svevo, for a more general purpose of establishing a high-throughput system for genetic map saturation. Primer combinations producing PCR products with at least 4–5 polymorphic bands were selected and analyzed across the mapping population. The PCR reactions produced a total of 2,881 fragments with an average of 52 peaks per reaction. A total of 142 new TRAP markers were mapped and found to be randomly distributed in the genome. The total length of the map was 2,043.0 cM, with an average chromosome length of 145.9 cM. Homoeologous group one had the highest number of TRAP markers (38 loci) and the longest map length (407.9 cM) for a total of 87 markers, while the homoeologous group five had the lowest TRAP marker number (5 loci) and the shortest map length (232.5 cM). The distribution of markers among the seven homoeologous groups was random. The results indicate that TRAP is highly efficient in genetic mapping, generating a large number of markers scattered across the genome. This closes many existing gaps in marker coverage and may join otherwise separate linkage groups.     

Has yield stability changed with genetic improvement of wheat yield?

The effect of plant breeding on yield and their physiological determinants has been widely studied in wheat. However, it is poorly understood how, and to what extent, yield stability has been modified. To attempt a direct analysis of changes in absolute and relative yield stability, data of yield of cultivars released in different eras in different environments were obtained from records from our lab and from the literature. Depending on the availability of data, effects of plant breeding on yield stability of cultivars released in Argentina, Australia, Italy and the United Kingdom were evaluated using a quantitative approach. In this paper it was assumed that the slope of yield vs. environmental index estimates the instability of the cultivars. In addition, a more qualitative approach for Mexico, and the former USSR complemented this analysis. There was a clear decrease in yield stability assessed in absolute terms as a consequence of wheat breeding. In Argentina, Australia, Italy and the UK this decrease was related to the magnitude of yield increases. However, the decrease in yield stability in Argentina and Australia was less than for Italy and the UK, particularly so during the last 30 years. Modern cultivars released in Argentina and Australia showed a trend to maintain yield stability as a percentage of their yield similar to that of their predecessors, while the two European countries analysed tended to a slight decrease in yield stability even in relative terms. The complementary, less quantitative evaluation of Mexico and the former USSR appeared to confirm the quantitative trends described for the other countries, i.e. a general decrease in yield stability (assessed in absolute terms) with genetic gains in yield potential. This revised version was published online in July 2006 with corrections to the Cover Date.