Different combinations of morpho‐physiological traits are responsible for tolerance to drought in wild tomatoes Solanum chilense and Solanum peruvianum

Herbaceous species can modify leaf structure during the growing season in response to drought stress and water loss. Evolution can select combinations of traits in plants for efficient water use in restricted environments. We investigated plant traits that mediate adaptation and acclimation to water stress in two herbaceous drought‐tolerant species. Anatomical, morphological and physiological traits related to stems and leaves were examined under optimal watering (OW) and a long period of restricted watering (RW) in 11 accessions from three Solanaceae species (Solanum chilense, S. peruvianum and S. lycopersicum). The relationships between these traits were tested using linear regression and PCA. There were significant differences in anatomical traits between the species under both OW and RW, where leaf area correlated with stem diameter. Proline and total carbohydrates accumulated highly in S. chilense and S. peruvianum, respectively, and these osmolytes were strongly correlated with increased osmotic potential. Stomatal density varied between species but not between acclimation treatments, while stomatal rate was significantly higher in wild tomatoes. There was a strong positive relationship between stem growth rate and a group of traits together expressed as total stomatal number. Total stomata is described by integration of leaf area, stomatal density, height and internode length. It is proposed that constitutive adaptations and modifications through acclimation that mediate RW play an important role in tolerance to drought stress in herbaceous plants. The capacity for growth under drought stress was not associated with any single combination of traits in wild tomatoes, since the two species differed in relative levels of expression of various phenotypic traits.     

Length‐weight relationship for sea catfishes (Siluriformes: Ariidae) from the southeastern Gulf of California with new records on maximum length

The parameters of length‐weight relationship (LWR) are presented for seven species of catfish from the southeastern Gulf of California. Samples were obtained every three months, in Bahia de Matanchen (using bottom trawl nets consistent of 72 hauls, with mesh sizes of 3.2 cm in the wings and 2.54 cm in the cod‐end) from February to November, 2016 and in the San Blas estuarine system (using gill nets consistent of 32 hauls, with mesh sizes of 5 cm) from August, 2015 to May, 2016 respectively. The allometric coefficient (b) of LWR varied from 2.797 for the Cominate Sea Catfish (Occidentarius platypogon (Günther, 1864)) to 3.373 for the Tete Sea Catfish (Ariopsis gilberti (Jordan & Williams, 1895)). Four species reached new records on maximum total length (Tete Sea Catfish, A. gilberti; Widehead Sea Catfish, A. guatemalensis (Günther, 1864); Conguito Sea Catfish, Cathorops liropus (Bristol, 1897); and Curator Sea Catfish, C. raredonae Marceniuk, Betancur‐R, & Acero, 2009). For six of these species this accounts for the first report on estimations of LWR parameters.     

Excitation of System I and System II in Photosynthesis as a Possible Control Mechanism of Glycolate Metabolism in the Blue-Green Alga Anacystis nidulans

Photosynthetic enhancement studies performed at 619 nm (excitation of Systems I and II) and at 446 nm (mainly excitation of System I) revealed an 18% photosynthetic enhancement simultaneously with a 31% reduction in glycolate excretion. This observation supports the hypothesis that some glycolate may be consumed in an oxidation process associated with System I when System II is poorly excited and the supply of electrons from the water splitting process of photosynthesis is low.     

Finding the best antibody dilution by repeated immunostaining of the same tissue section

One can find the optimal antibody dilution for immunostaining by repeated staining on the same tissue section by using a less dilute antibody for each attempt. Using secondary antibody and horseradish peroxidase conjugated to a dextran polymer, a section stained repeatedly with several dilutions of antibody appears as good as a section stained with only the last dilution.     

Aromatase activity after a short-course of letrozole administration in adult men at sea level and at high altitude (with or without excessive erythrocytosis)

Men living at high altitudes in Peru compared to sea level counterparts have erythrocytosis (hemoglobin 16-21?g/dl) or excessive erythrocytosis (hemoglobin>21?g/dl). High testosterone (T) levels in men at high altitude (HA) were associated with excessive erythrocytosis. High androgen levels could be due to a low aromatase activity or to an elevated rate of conversion from precursors to testosterone. The aim of this study was to evaluate aromatase activity and rate of conversion from precursors to testosterone before and after administration of the aromatase enzyme inhibitor letrozole (5?mg/day) for a 5-day period to men at HA and at sea level (SL). The response to short term aromatase inhibition was assessed in 30 adult men living at sea level, 31 native men at HA with erythrocytosis (Hb 16-21?g/dl), and 35 men at HA with excessive erythrocytosis (Hb>21?g/dl). Serum hormone levels, estradiol/testosterone, testosterone/androstenedione, and testosterone/dehydroepiandrosterone sulfate (DHEAS) ratios were measured. Men with erythrocytosis had lower basal serum T/androstenedione ratios than men with excessive erythrocytosis at HA and men at sea level. Men at HA with excessive erythrocytosis had higher T/DHEAS ratios than men with erythrocytosis and than those at sea level before and after letrozole administration. After letrozole administration, both groups of men at high altitude (with erythrocytosis or with excessive erythrocytosis) showed lower aromatase activities than those at sea level. In conclusion, higher serum testosterone levels in men with excessive erythrocytosis were associated with an increased rate of conversion from DHEAS to testosterone rather than to a lower aromatase activity.     

Nerve growth factor induces the expression of chaperone protein calreticulin in human epithelial ovarian cells

Epithelial ovarian cancer is highly angiogenic and high expression of Nerve Growth Factor (NGF), a proangiogenic protein. Calreticulin is a multifunctional protein with anti-angiogenic properties and its translocation to the tumor cell membrane promotes recognition and engulfment by dendritic cells. The aim of this work was to evaluate calreticulin expression in human normal ovaries, benign and borderline tumors, and epithelial ovarian cancer samples and to evaluate whether NGF regulates calreticulin expression in human ovarian surface epithelium and in epithelial ovarian cancer cell lines. Calreticulin mRNA and protein levels were analyzed using RT-PCR, Western blot and immunohistochemistry in 67 human ovarian samples obtained from our Institution. Calreticulin expression induced by NGF stimulation in cell lines was evaluated using RT-PCR, Western blot and immunocytochemistry. We found a significant increase of calreticulin mRNA levels in epithelial ovarian cancer samples as compared to normal ovaries, benign tumors, and borderline tumors. Calreticulin protein levels, evaluated by Western blot, were also increased in epithelial ovarian cancer with respect to benign and borderline tumors. When HOSE and A2780 cell lines were stimulated with Nerve Growth Factor, we found an increase in calreticulin protein levels compared to controls. This effect was reverted by GW441756, a TRKA specific inhibitor. These results suggest that NGF regulates calreticulin protein levels in epithelial ovarian cells through TRKA receptor activation.     

Molecular modeling of <Emphasis Type="Italic">Trypanosoma cruzi</Emphasis> glutamate cysteine ligase and investigation of its interactions with glutathione

Trypanosoma cruzi glutamate cysteine ligase (TcGCL) is considered a potential drug target to develop novel antichagasic drugs. We have used a variety of computational methods to investigate the interactions between TcGCL with Glutathione (GSH). The three-dimensional structure of TcGCL was constructed by comparative modeling methods using the Saccharomyces cerevisiae glutamate cysteine ligase as template. Molecular dynamics simulations were used to validate the TcGCL model and to analyze the molecular interactions with GSH. Using RMSD clustering, the most prevalent GSH binding modes were identified paying attention to the residues involved in the molecular interactions. The GSH binding modes were used to propose pharmacophore models that can be exploited in further studies to identify novel antichagasic compounds.     

Effect of sleep stage on breathing in children with central hypoventilation.

The early literature suggests that hypoventilation in infants with congenital central hypoventilation syndrome (CHS) is less severe during rapid eye movement (REM) than during non-REM (NREM) sleep. However, this supposition has not been rigorously tested, and subjects older than infancy have not been studied. Given the differences in anatomy, physiology, and REM sleep distribution between infants and older children, and the reduced number of limb movements during REM sleep, we hypothesized that older subjects with CHS would have more severe hypoventilation during REM than NREM sleep. Nine subjects with CHS, aged (mean +/- SD) 13 +/- 7 yr, were studied. Spontaneous ventilation was evaluated by briefly disconnecting the ventilator under controlled circumstances. Arousal was common, occurring in 46% of REM vs. 38% of NREM trials [not significant (NS)]. Central apnea occurred during 31% of REM and 54% of NREM trials (NS). Although minute ventilation declined precipitously during both REM and NREM trials, hypoventilation was less severe during REM (drop in minute ventilation of 65 +/- 23%) than NREM (drop of 87 +/- 16%, P = 0.036). Despite large changes in gas exchange during trials, there was no significant change in heart rate during either REM or NREM sleep. We conclude that older patients with CHS frequently have arousal and central apnea, in addition to hypoventilation, when breathing spontaneously during sleep. The hypoventilation in CHS is more severe during NREM than REM sleep. We speculate that this may be due to increased excitatory inputs to the respiratory system during REM sleep.     

The Effect of Chitosan as Internal or External Coating on the 5-ASA Release from Calcium Alginate Microparticles

The effect of chitosan as internal or external coating on the mesalamine (5-ASA) release from calcium alginate microparticles (CaAl) was studied, and a delayed release of 5-ASA system intended for colonic drug delivery was developed. The external chitosan coating was developed by immersion of wetted CaAl in chitosan solution and the internal coating by mixing 5-ASA with chitosan solution and drying before the preparation of CaAl. Both systems were coated with Acryl-EZE^® using combined fluid bed coating and immersion procedure. The results showed that in phosphate medium (pH 7.5), chitosan as 5-ASA coating promotes a quick erosion process accelerating drug release, but chitosan as external coating (CaAlCS) does not increase the T ₅₀ value compared with the microparticles without chitosan (CaAl). Chitosan as internal or external coating was not effective to avoid the quick 5-ASA release in acidic medium (pH 1.2). The presence of β-glucosidase enzymes increases significantly the 5-ASA release for CaAl, while no effect was observed with chitosan as internal or external coating. Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray data revealed that 5-ASA did not form a solid solution but was dispersed in the microparticles. The Acryl-EZE^® coating of microparticles was effective because all the formulations showed a low release, less than 15%, of 5-ASA in acid medium at pH 1.2. Significant differences in the percentage of 5-ASA released between formulations were observed in phosphate buffer at pH 6.0. In phosphate buffer at pH 7.2, all the formulations released 100% of 5-ASA.