Changes in gene expression patterns associated with microspore embryogenesis in hexaploid triticale (×Triticosecale Wittm.)

To gain a better understanding of the molecular mechanisms controlling microspore embryogenesis (ME) in triticale (×Triticosecale Wittm.), the expression patterns of 13 genes, previously identified in bread wheat to be associated with microspore-derived embryo development, were analysed. Four triticale doubled haploid (DH) lines, significantly different with respect to embryogenic potential, were studied. The gene expression profile was dissected at different points of the ME induction procedure up to the 8th day of in vitro culture (dc). RT-PCR revealed that these 13 genes were expressed during triticale ME. Variations in gene expression profiles were observed between the studied DH lines. DH28 (highly embryogenic) was the only one in which all analysed genes (Ta.TPD1-like, TAA1b, GSTF2, GSTA2, CHI3, Tad1, XIP-R1, TaAGL14, TaNF-YA7, SERK2, SERK1, TaEXPB4, TaME1) were up-regulated during the first 8dc. In the less embryogenic DH31, TAA1b, GSTA2 and TaEXPB4 were already induced on 4dc. In DH25, ME was initiated quite efficiently but soon inhibited, which coincided with the lack of gene expression (TaEXPB4, TaME1) or down-regulation (Tad1, XIP-R1, TaAGL14, TaNF-YA, SERK2, SERK1) on 8dc. In the recalcitrant DH50 line, the majority of genes were expressed at a lower level or not at all, indicating disturbances in ME initiation. In this study, the molecular mechanisms involved in triticale ME induction were analysed for the first time, laying the foundation for further characterisation of specific genes controlling microspore-derived embryo development.     

The Effect of Copper on the Color of Shrimps: Redder Is Not Always Healthier

The objective of this research is to test the effects of copper on the color of pacific white shrimp (Litopenaeus vannamei) invivo. Forty-eight shrimps (L. vannamei) were exposed to a low concentration of copper (1 mg/L; experimental treatment) and forty-eight shrimps were used as controls (no copper added to the water). As a result of this experiment, it was found that shrimps with more copper are significantly redder than those designated as controls (hue _{(500–700 nm)}: P = 0.0015; red chroma _{(625–700 nm)}: P<0.0001). These results indicate that redder color may result from exposure to copper and challenge the commonly held view that highly pigmented shrimps are healthier than pale shrimps.     

Phenotypic trait differences between Iris pseudacorus in native and introduced ranges support greater capacity of invasive populations to withstand sea level rise

Aim

Tidal wetlands are greatly impacted by climate change, and by the invasion of alien plant species that are being exposed to salinity changes and longer inundation periods resulting from sea level rise. To explore the capacity for the invasion of Iris pseudacorus to persist with sea level rise, we initiated an intercontinental study along estuarine gradients in the invaded North American range and the native European range.

Location

San Francisco Bay-Delta Estuary; California, USA and Guadalquivir River Estuary; Andalusia, Spain.

Methods

We compared 15 morphological, biochemical, and reproductive plant traits within populations in both ranges to determine if specific functional traits can predict invasion success and if environmental factors explain observed phenotypic differences.

Results

Alien I. pseudacorus plants in the introduced range had more robust growth than plants in the native range. The vigour of the alien plants was reflected by expression of higher leaf water content, fewer senescent leaves per leaf fan, and more carbohydrate storage reserves in rhizomes than plants in the native range. Moreover, alien plants tended to show higher specific leaf area and seed production than native plants. I. pseudacorus plants in the introduced range were less affected by increasing salinity and were exposed to deeper inundation water along the estuarine gradient than those in the native range.

Main Conclusions

Functional trait differences suggest mature populations of I. pseudacorus in the introduced range have greater adapted capacity to adjust to environmental stresses induced by rising sea level than those in the native range. Knowledge of these trait responses can be applied to improve risk assessments in invaded estuaries and to achieve climate-adapted conservation goals for conservation of the species in its native range.     

Dana swimming crab growth Callinectes danae (Decapoda: Portunidae) from Margarita Island, Venezuela

Callinectes danae is a common species captured with crab traps in nearby areas of coastal lagoons in Margarita Island. Although its considerable economic importance as a fishery resource, few studies have been done on population dynamics and its fishery potential in local coastal environments to support decision making in fishery administration. We present growth pattern details of Callinectes danae to better estimate its population size and exploitation feasibility. For this, we analyzed a total of 3 623 specimens that were monthly captured in crab pots by artisanal fishermen in Las Marites lagoon, from October 2007 to September 2008. The length-weight ratio was determined, and growth parameters estimated from both length and weight curves of the von Bertalanffy model. The general sex ratio showed no significant difference between males and females (chi2 = 0.04, p > 0.05). However, values of slopes b between males and females were significantly different (t(s) = 2.75, p < 0.05), as well as intercepts a (t(s) = 2.44, p < 0.05). Thus, the length-weight ratio was determined separately: W = 7.48e(-5)*L(2.98) for males and W = 1.21e(-4)*L(2.87) for females, indicating a negative allometric growth in both sexes. Growth parameters were established as: L(infinity) =134.80mm, W(infinity) = 166.04g and k = 0.86/yr for males; L(infinity) = 122.35mm, W(infinity) = 118.45g and k = 0.63/yr for females. Lifespan was estimated at 3.05 years for males and 4.24 years for females. We concluded that Callinectes danae is a species with short lifespan and moderately rapid growth. The coefficient of variation values (CV), of the phi-prime growth performance index (?'), showed a different growth pattern compared to those obtained in other regions. We propose that a management strategy will be the periodical review of the minimum capture size for fishing area, after the great variability found in growth parameters.     

Natural parasitism of Metaparasitylenchus hypothenemi (Tylenchida: Allantonematidae) on the coffee berry borer in Chiapas,Mexico

We assessed the parasitism of Metaparasitylenchus hypothenemi on its host, the coffee berry borer, in 20 coffee plantations of Mexico. A total of 23,568 adult borers were dissected, with 179 of these infected with nematodes (0.76% infection rate). Although the level of parasitism is not encouraging, the nematode is another natural enemy, which limits the population growth of this pest in Mexico.     

Reactive nitrogen and oxygen species activate different sphingomyelinases to induce apoptosis in airway epithelial cells

Airway epithelial cells are constantly exposed to environmental insults such as air pollution or tobacco smoke that may contain high levels of reactive nitrogen and reactive oxygen species. Previous work from our laboratory demonstrated that the reactive oxygen species (ROS), hydrogen peroxide (H(2)O(2)), specifically activates neutral sphingomyelinase 2 (nSMase2) to generate ceramide and induce apoptosis in airway epithelial cells. In the current study we examine the biological consequence of exposure of human airway epithelial (HAE) cells to reactive nitrogen species (RNS). Similar to ROS, we hypothesized that RNS may modulate ceramide levels in HAE cells and induce apoptosis. We found that nitric oxide (NO) exposure via the NO donor papa-NONOate, failed to induce apoptosis in HAE cells. However, when papa-NONOate was combined with a superoxide anion donor (DMNQ) to generate peroxynitrite (ONOO(-)), apoptosis was observed. Similarly pure ONOO(-)-induced apoptosis, and ONOO(-)-induced apoptosis was associated with an increase in cellular ceramide levels. Pretreatment with the antioxidant glutathione did not prevent ONOO(-)-induced apoptosis, but did prevent H(2)O(2)-induced apoptosis. Analysis of the ceramide generating enzymes revealed a differential response by the oxidants. We confirmed our findings that H(2)O(2) specifically activated a neutral sphingomyelinase (nSMase2). However, ONOO(-) exposure did not affect neutral sphingomyelinase activity; rather, ONOO(-) specifically activated an acidic sphingomyelinase (aSMase). The specificity of each enzyme was confirmed using siRNA to knockdown both nSMase2 and aSMase. Silencing nSMase2 prevented H(2)O(2)-induced apoptosis, but had no effect on ONOO(-)-induced apoptosis. On the other hand, silencing of aSMase markedly impaired ONOO(-)-induced apoptosis, but did not affect H(2)O(2)-induced apoptosis. These findings support our hypothesis that ROS and RNS modulate ceramide levels to induce apoptosis in HAE cells. However, we found that different oxidants modulate different enzymes of the ceramide generating machinery to induce apoptosis in airway epithelial cells. These findings add to the complexity of how oxidative stress promotes lung cell injury.     

Regulation of nitrate reductase inRhodobacter capsulatus E1F1

The photosynthetic purple non-sulfur nitrate-assimilating bacteriumRhodobacter capsulatus E1F1 has an adaptive nitrate reductase activity inducible by either nitrate or nitrite and molybdenum traces. Nitrate reductase induction by nitrate did not occur in media with nitrate and ammonium, which showed no effect if nitrite was the inductor instead of nitrate or in the presence ofl-methionine-dl-sulfoximine (MSX) plus nitrate. In vivo, tungstate inhibited nitrate reductase activity, and this was not recovered upon addition of molybdenum unless de novo protein synthesis took place. Nitrate reductase was also repressed in nitrogen-starved cells or after the addition of azaserine to cells growing phototrophically with nitrate. Moreover, higher rates of nitrate reductase induction and nitrite excretion were found in illuminated cells grown with nitrate under air than in those grown under argon.     

The effect of the flavonoid diosmin, grape seed extract and red wine on the pulmonary metastatic B16F10 melanoma

OBJECTIVE: To study the effect of different phenolic compounds and red wine on pulmonary metastatic melanoma. METHODS: Swiss mice were inoculated with 500000 melanocytes B16F10 and given oral doses of diosmin, grape seed extract (GSE) and red wine. A macroscopic count was made of the metastatic nodules on the lung surface and a microscopic study by image analysis of five sections, calculating the implantation percentage and tumoral growth and invasion indices. RESULTS: Macroscopically, the group treated with diosmin showed the greatest reduction (52%) in the number of metastatic nodules compared with the control group, which was treated with ethanol, while GSE and red wine caused decreases of 26.07 and 28.81%, respectively. Microscopically, there was a decrease in the implantation percentage after the administration of diosmin (79.4%) and red wine (20.19%), and an increase of 2.12% after the administration of GSE, all relative to the ethanol-treated control. As regards the growth index, diosmin produced a reduction of 67.44% and red wine a reduction of 20.62%, while GSE again produced an increase (25.33%). The reductions in the invasion index were 45.23, 31.65 and 17.57% with diosmin, GSE and red wine, respectively. CONCLUSIONS: Diosmin originated the greatest reduction in pulmonary metastases, both at the macroscopic and microscopic levels.     

Synthesis and antiprotozoal activity of nitazoxanide–N-methylbenzimidazole hybrids

A series of a novel hybrid compounds between nitazoxanide and N-methylbenzimidazole were synthesized starting from the corresponding N-methyl-2-nitroanilines. The new hybrid compounds (1–13) were evaluated in vitro against Giardia intestinalis, Entamoeba histolytica, Trichomonas vaginalis. NTZ, MTZ and ABZ were used as drug standards. Experimental evaluations revealed all of the new compounds (1–13) were active and showed strong activity against the three protozoa, particularly with E. histolytica where the IC₅₀ values ranged between 3 and 69 nM.Overall, compounds 2, 5, 7, 8, 9, 11 and 12 stood out with values lower than 87 nM for all three protozoa, comparatively better than the reference drugs.     

Nucleotide utilization requirements that render ClpB active as a chaperone

ClpB is a member of the AAA+ superfamily that forms a ring-shaped homohexamer. Each protomer contains two nucleotide binding domains arranged in two rings that hydrolyze ATP. We extend here previous studies on ClpB nucleotide utilization requirements by using an experimental approach that maximizes random incorporation of different subunits into the protein hexamer. Incorporation of one subunit unable to bind or hydrolyze ATP knocks down the chaperone activity, while the wt hexamer can accommodate two mutant subunits that hydrolyze ATP in only one protein ring. Four subunits seem to build the functional cooperative unit, provided that one of the protein rings contains active nucleotide binding sites.