Eco-physiological response to water stress of drought-tolerant and drought-sensitive tomato genotypes

Water stress is an increasing environmental constraint affecting tomato growth and yield in Mediterranean areas. Solanum pennellii is a wild tomato species that exhibits a higher water use efficiency compared with cultivated S. lycopersicum. In particular, a cultivated line carrying a small S. pennellii region on chromosome 9 (IL 9-2-5) was identified as more tolerant to water deficit. In this work, the tolerant (IL 9-2-5) and the susceptible (M82) genotypes were subjected to three different water regimes: irrigation with 100% (V1), 50% (V2) and 25% (V3) field capacity. To evaluate the physiological response of IL 9-2-5 and M82 to water deficit, leaf functional traits, plant biomass production and maximal PSII photochemical efficiency were measured together with photosynthetic pigments and phenolic compounds. The higher tolerance to water deficiency of IL 9-2-5 was associated with the development of a better antioxidant system, especially in treatment V3. In addition, IL 9-2-5 had higher values of sclerophylly and leaf dry matter content thus confirming that the tolerance of IL 9-2-5 can be attributed to traits related to leaf morphology and physiology. In future, identification of polymorphisms in key-genes controlling these traits can guide breeding efforts aimed at improving susceptible genotypes.     

Genetic control of H-Y synthesis. A hypothesis

Summary In view of the claimed serological H-Y positivity observed in patients with ovarian dysgenesis (for example, 45,X) and in XO mice (neither of whom have a Y chromosome), it is suggested that genetic control is exercised over the H-Y system by structural genes on the pairing segments of the X and Y chromosomes, acting on an autosomally coded H-Y precursor.     

Fecal lactoferrin and intestinal permeability are effective non-invasive markers in the diagnostic work-up of chronic diarrhea

Non-invasive markers able to identify patients with chronic diarrhea at risk of organic disease are missing. Aim of the study was to assess the diagnostic ability of intestinal permeability (IP) test and fecal lactoferrin (FL) in distinguishing functional from organic disease in patients with chronic diarrhea. We retrospectively enrolled patients referring to the gastroenterology outpatient clinic for chronic diarrhea. Among the 103 patients included, 40 % had an organic disease, with IP and FL levels significantly higher compared to those with a functional disorder (p < 0.0001). Sensitivity, specificity, positive and negative likelihood ratios, area under ROC curves of FL were superior to those of IP in discriminating functional and organic disease (FL: 87.8 and 93.6 %, 13.61 and 0.13, 0.9375; IP: 61.0 and 90.3 %, 6.3 and 0.43, 0.7691). When combining the two tests, the diagnostic ability of FL did not improve. In subgroup analysis, IP confirmed its ability to detect small bowel alterations, while FL could identify both small bowel and colonic alterations. In conclusion, FL is valid to detect inflammation in the gastrointestinal tract, while IP can effectively identify small bowel damage in chronic diarrhea patients. Together these tests could recognize both the presence of intestinal damage and its site.     

The PP2A-Integrator-CDK9 axis fine-tunes transcription and can be targeted therapeutically in cancer

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Plumage maintenance affects ultraviolet colour and female preference in the budgerigar

Elaborate or colourful feathers are important traits in female-mate choice in birds but little attention has been given to the potential costs of maintaining these traits in good condition via preening behaviour. While preening is known to be an important component of plumage maintenance, it has received little attention with respect to colouration. We investigated whether preening can influence plumage reflectance and whether females show a preference for plumage cleanliness in captive-bred, wild-type budgerigars, Melopsittacus undulatus. To do this, we compared the spectral colour of birds that were allowed to preen their plumage and individuals that were prevented from preening. The plumage of birds that were prevented from preening showed a significant lower reflectance in the UV range (300-400 nm). Subsequently, we measured females’ preferences for preened and unpreened males using a two-choice test. In a second experiment we allowed females to choose between an unpreened male and a male smeared with UV-absorbing chemicals (UV-blocked male). The proportion of time that females stayed near preened males was statistically higher than for unpreened males, but females spent similar amounts of time with unpreened males and UV-blocked males. These results are consistent with the idea that female budgerigars are able to discriminate between preened and unpreened males, and that UV colours, mediated by preening, can convey information about a bird's current condition.     

Structural and functional characterization of CcmG from Pseudomonas aeruginosa,a key component of the bacterial cytochrome c maturation apparatus

The cytochrome c maturation process is carried out in the bacterial periplasm, where some specialized thiol‐disulfide oxidoreductases work in close synergy for the correct reduction of oxidized apocytochrome before covalent heme attachment. We present a structural and functional characterization of the soluble periplasmic domain of CcmG from the opportunistic pathogen P. aeruginosa (Pa‐CcmG), a component of the protein machinery involved in cyt c maturation in gram‐negative bacteria. X‐ray crystallography reveals that Pa‐CcmG is a TRX‐like protein; high‐resolution crystal structures show that the oxidized and the reduced forms of the enzyme are identical except for the active‐site disulfide. The standard redox potential was calculated to be E^0′ = ?0.213 V at pH 7.0; the pK_a of the active site thiols were pK_a = 6.13 ± 0.05 for the N‐terminal Cys74 and pK_a = 10.5 ± 0.17 for the C‐terminal Cys77. Experiments were carried out to characterize and isolate the mixed disulfide complex between Pa‐CcmG and Pa‐CcmH (the other redox active component of System I in P. aeruginosa). Our data indicate that the target disulfide of this TRX‐like protein is not the intramolecular disulfide of oxidized Pa‐CcmH, but the intermolecular disulfide formed between Cys28 of Pa‐CcmH and DTNB used for the in vitro experiments. This observation suggests that, in vivo, the physiological substrate of Pa‐CcmG may be the mixed‐disulfide complex between Pa‐CcmH and apo‐cyt. Proteins 2010. © 2010 Wiley‐Liss, Inc.