Coupling physiological analysis with proteomic profile to understand the photosynthetic responses of young Euterpe oleracea palms to drought

Photosynthesis Research - This study examined whether drought sensitivity in açaí (Euterpe oleracea Mart.) is associated with reductions in photosynthesis and increasing oxidative stress...     

Alternatives for biosurfactants and bacteriocins extraction from Lactococcus lactis cultures produced under different pH conditions

Aims: Study of the potential of Lactococcus lactis CECT‐4434 as a biosurfactants and nisin (the only bacteriocin allowed to be used in the food industry) producer for industrial applications, exploiting the possibility of recovering separately both metabolites, taking into account that L. lactis is an interesting micro‐organism with several applications in the food industry because it is recognized as GRAS. Methods and Results: The results showed the ability of this strain to produce cell‐bound biosurfactants, under controlled pH, and cell‐bound biosurfactants and bacteriocins, when pH was not controlled. Three extraction procedures were designed to separately recover these substances. Conclusions: The strain L. lactis CECT‐4434 showed to be a cell‐bound biosurfactants and bacterocins producer when fermentations were carried out under uncontrolled pH. Both products can be recovered separately. Significance and Impact of the Study: Development of a convenient tool for the extraction of cell‐bound biosurfactants and bacteriocins from the fermentation broth.     

Mapping baroreceptor function to genome: a mathematical modeling approach

To gain information about the genetic basis of a complex disease such as hypertension, blood pressure averages are often obtained and used as phenotypes in genetic mapping studies. In contrast, direct measurements of physiological regulatory mechanisms are not often obtained, due in large part to the time and expense required. As a result, little information about the genetic basis of physiological controlling mechanisms is available. Such information is important for disease diagnosis and treatment. In this article, we use a mathematical model of blood pressure to derive phenotypes related to the baroreceptor reflex, a short-term controller of blood pressure. The phenotypes are then used in a quantitative trait loci (QTL) mapping study to identify a potential genetic basis of this controller.     

Nitric oxide synthase-mediated phytoalexin accumulation in soybean cotyledons in response to the Diaporthe phaseolorum f. sp. meridionalis elicitor

Phytoalexin biosynthesis is part of the defense mechanism of soybean (Glycine max) plants against attack by the fungus Diaporthe phaseolorum f. sp. meridionalis (Dpm), the causal agent of stem canker disease. The treatment of soybean cotyledons with Dpm elicitor or with sodium nitroprusside (SNP), a nitric oxide (NO) donor, resulted in a high accumulation of phytoalexins. This response did not occur when SNP was replaced by ferricyanide, a structural analog of SNP devoid of the NO moiety. Phytoalexin accumulation induced by the fungal elicitor, but not by SNP, was prevented when cotyledons were pretreated with NO synthase (NOS) inhibitors. The Dpm elicitor also induced NOS activity in soybean tissues proximal to the site of inoculation. The induced NOS activity was Ca(2+)- and NADPH-dependent and was sensitive to the NOS inhibitors N(G)-nitro-L-arginine methyl ester, aminoguanidine, and L-N(6)-(iminoethyl) lysine. NOS activity was not observed in SNP-elicited tissues. An antibody to brain NOS labeled a 166-kD protein in elicited and nonelicited cotyledons. Isoflavones (daidzein and genistein), pterocarpans (glyceollins), and flavones (apigenin and luteolin) were identified after exposure to the elicitor or SNP, although the accumulation of glyceollins and apigenin was limited in SNP-elicited compared with fungal-elicited cotyledons. NOS activity preceded the accumulation of these flavonoids in tissues treated with the Dpm elicitor. The accumulation of these metabolites was faster in SNP-elicited than in fungal-elicited cotyledons. We conclude that the response of soybean cotyledons to Dpm elicitor involves NO formation via a constitutive NOS-like enzyme that triggers the biosynthesis of antimicrobial flavonoids.     

Selective inhibition of protein kinases blocks the formation of a new axis,the beginning of budding,in Hydra

In Hydra, head regeneration and bud formation appear to be very similar processes. The fact that there are genes whose expression is specific for one of the two processes suggests that they do not have identical molecular bases. We analyzed the signal transduction pathways regulating bud development using inhibitors of protein kinase C, Src, PI3K and ERK. The four inhibitors reversibly blocked bud formation in Hydra when applied before stage 1. Once the bud reached stage 3, three of them had no effect and the bud developed normally. The inhibitors blocked the expression of Budhead, an early head marker, and of CnOtx which are specific for bud formation. The results are in agreement with the central role of a signaling pathway mediated by Src on bud development.     

Interleukin-dependent modulation of HLA-DR expression on CD4and CD8 activated T cells

Summary Interleukins (IL) regulate different T-cell surface Ag known as activation markers that have distinct functional roles. In this paper, while studying the influence of some cytokines(IL-12, IL-2 and IL-4) on the expression of several markers [CD69,CD25, CD26, CD3, human leukocyte antigen (HLA-DR), CD45R0] in in vitro activated human T lymphocytes, we observed two groups of donors responding to phytohaemagglutinin (PHA) activation with high or low HLA-DRAg expression. We also found that CD4 and CD8 populations had different HLA-DR densities under PHA activation (particularly the high HLA-DR-expressing group). Interleukins, in a dose-dependent manner (IL-2 partially),upregulated these HLA-DR levels. In 5 day cultures, IL-12 and IL-2 enhanced the CD8/CD4 ratio of activated T cells,which was responsible, in part, for the IL-dependent HLA-DR upregulation.IL-12 and IL-2 also upregulated the HLA-DR expression at the molecular level on CD8, and IL-12 downregulated it on CD4 cells. It seems that IL-4 upregulated HLA-DR by shortening the mitogen-dependent regulation kinetics. We hypothesize that the different effect of each IL on HLA-DR expression might be related to the regulation of the dose of antigenic peptide presentation and, thus, also influence TH1/TH2 dominance.     

Neurotransmission of autonomic components of aortic baroreceptor afferents in the NTS of awake rats

The effect of sequential blockade of N-methyl-D-aspartic acid (NMDA) receptors with DL-2-amino-5-phosphonopentanoic acid (AP-5) and non-NMDA receptors with 6,7-dinitroquinoxaline-2,3 dione (DNQX) in the nucleus tractus solitarii (NTS) on the cardiovascular responses to electrical stimulation (ES) of the aortic depressor nerve (ADN) was evaluated in awake rats. Two protocols were used. In protocol 1, bilateral microinjection of AP-5 into the NTS (n = 7) reduced the hypotensive response to ES of the ADN; subsequent microinjection of DNQX produced additional reduction in this response. AP-5 reduced the bradycardic response, and DNQX almost abolished this response. In protocol 2, bilateral microinjection of DNQX into the NTS (n = 6) reduced the hypotensive response, and subsequent microinjection of AP-5 significantly reduced this response. DNQX produced a significant reduction in bradycardic response, and AP-5 abolished this response. The data indicate that processing of the parasympathetic component of the NTS aortic baroreceptor afferents is mediated by both NMDA and non-NMDA receptors, whereas processing of the sympathoinhibitory component seems to be only partially mediated by ionotropic receptors.     

Pfannenstiel incision as an alternative approach for harvesting the rectus abdominis muscle for free-tissue transfer

The rectus abdominis muscle has been one of the most commonly used donor tissues for free-flap reconstruction of defects in the extremities and in selected head and neck patients. The rectus abdominis has provided adequate soft-tissue mass with predictable anatomy and results for the majority of its applications in free-flap reconstruction. Harvesting of this muscle has typically been done through a paramedian or midline incision, which has left a lengthy notable scar on a patient's abdomen. To avoid the late aesthetic deformity associated with this typical approach for the rectus abdominis, we began harvesting the muscle through a Pfannenstiel incision. Patients were initially selected based on young age and limited soft-tissue requirements. With additional experience, this technique was extended to include all healthy patients regardless of age. Also, soft-tissue limitations no longer became an issue, as we learned the entire rectus abdominis muscle could be harvested from this approach. An extended Pfannenstiel incision was made from the ipsilateral anterior superior iliac spine to the lateral border of the contralateral rectus abdominis. A superiorly based flap was raised to expose the full length of the anterior rectus sheath from pubis to costal margin. In our earlier patients, a periumbilical incision was made for presumed easier access, but we discovered this was an unnecessary maneuver. With the anterior sheath fully exposed, the muscle was harvested and the sheath repaired in a routine manner. The elevated abdominal flap was returned to its anatomic position and closed over a suction drain. Since 1993, 10 patients have undergone a Pfannenstiel approach for harvesting of the rectus abdominis muscle. The mean age was 16. The areas requiring coverage included a traumatic elbow defect, seven traumatic lower extremity defects, one lower extremity sarcoma defect, and one lower extremity septic joint defect. Mean follow-up for these patients was 12 months. There were no flap failures. One patient developed an arterial thrombosis on postoperative day 5 and was treated with successful revision. There were no abdominal wall complications. Cosmesis was judged as good in all patients. We would recommend avoiding this approach in heavy or moderate smokers, diabetic patients, and patients with significant obesity. The Pfannenstiel approach to the rectus abdominis muscle has allowed for complete harvest of the muscle, improved aesthetic results compared with alternative techniques, and avoidance of donor-site morbidityin healthy patients.