Pore formation by Cry toxins.

Bacillus thuringiensis (Bt) bacteria produce insecticidal Cry and Cyt proteins used in the biological control of different insect pests. In this review, we will focus on the 3d-Cry toxins that represent the biggest group of Cry proteins and also on Cyt toxins. The 3d-Cry toxins are pore-forming toxins that induce cell death by forming ionic pores into the membrane of the midgut epithelial cells in their target insect. The initial steps in the mode of action include ingestion of the protoxin, activation by midgut proteases to produce the toxin fragment and the interaction with the primary cadherin receptor. The interaction of the monomeric CrylA toxin with the cadherin receptor promotes an extra proteolytic cleavage, where helix alpha-1 of domain I is eliminated and the toxin oligomerization is induced, forming a structure of 250 kDa. The oligomeric structure binds to a secondary receptor, aminopeptidase N or alkaline phosphatase. The secondary receptor drives the toxin into detergent resistant membrane microdomains formingpores that cause osmotic shock, burst of the midgut cells and insect death. Regarding to Cyt toxins, these proteins have a synergistic effect on the toxicity of some Cry toxins. Cyt proteins are also proteolytic activated in the midgut lumen of their target, they bind to some phospholipids present in the mosquito midgut cells. The proposed mechanism of synergism between Cry and Cyt toxins is that Cyt1Aa function as a receptor for Cry toxins. The Cyt1A inserts into midgut epithelium membrane and exposes protein regions that are recognized by Cry11Aa. It was demonstrated that this interaction facilitates the oligomerization of Cry11Aa and also its pore formation activity.

Usefulness of the sFlt-1/PlGF (Soluble fms-Like Tyrosine Kinase-1/Placental Growth Factor) Ratio in Diagnosis or Misdiagnosis in Women With Clinical Diagnosis of Preeclampsia.

Preeclampsia is characterized by angiogenic imbalance (AI), sFlt-1 (soluble fms-like tyrosine kinase-1)/PlGF (placental growth factor) is useful for its diagnosis and prediction of adverse outcomes, but the relationship among the degrees of AI as assessed by this ratio with the correct diagnosis, clinical characteristics, and outcomes in women with clinical diagnosis of preeclampsia are unclear. We studied 810 women with clinical diagnosis of preeclampsia. Patients were divided into 3 groups based on their degree of AI, evaluated by the sFlt-1/PlGF ratio: no AI (≤38), mild AI (>38-<85), and severe AI (≥85). Patients with no AI were more likely to have comorbidities and false significant proteinuria compared with patients with mild and severe AI (P<0.001). The rates of preterm delivery, delivery within 14 days, and small-for-gestational-age infant were higher among patients with severe AI than in patients with no and mild AI (P<0.001) and in patients with mild AI that in those with no AI (P≤0.01). The occurrence of any adverse maternal outcome (HELLP syndrome, elevated liver enzymes, thrombocytopenia, placental abruption, acute kidney injury) was only present in patients with severe AI. Interestingly, the frequency of misdiagnosis of preeclampsia was progressively lower as the degrees of AI increased (no AI: 100%, mild AI: 88.2%, and severe AI: 15.6%). We concluded that in women with clinical diagnosis of preeclampsia, severe AI is characterized by high frequency of true preeclampsia and preeclampsia-related adverse outcomes, in contrast, no and mild AI, are characterized by unnecessary early deliveries, often due to misdiagnosis.

Soluble Endoglin As a Marker for Preeclampsia, Its Severity, and the Occurrence of Adverse Outcomes.

Preeclampsia is characterized by an imbalance in angiogenic factors, including sEng (soluble endoglin). However, the relationship of sEng with the severity of preeclampsia, clinical, and laboratory parameters, and the occurrence of adverse outcomes are not fully elucidated. We studied 1002 women with preeclampsia. Serum concentrations of sEng were measured by ELISA. Serum sEng levels were significantly different (P<0.001) in patients with preeclampsia than in healthy pregnancy. In addition, these factors were markedly different in patients with hemolysis, elevated liver enzymes, low platelet count syndrome and eclampsia than in patients with preeclampsia with or without severe features (P<0.001) and in patients with preeclampsia with severe features than in those without severe features (P<0.001). sEng correlated positively with blood pressure, proteinuria, and levels of creatinine, uric acid, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase; and inversely with gestational age, infant's birth weight, and platelets counts (P<0.001 for all). The risk of combined and specific adverse outcomes (pulmonary edema, acute renal failure, placental abruption, hepatic hematoma or rupture, maternal death, cerebral hemorrhage, thrombocytopenia, elevated liver enzymes, preterm delivery, small for gestational age infant, and need for endotracheal intubation, positive inotropic drug support, and hemodialysis) was higher in patients with sEng values in the highest quartile (odds ratio ≥3.1) compared with the lowest quartile. Patients in the highest quartile of sEng were more likely to deliver early compared with those in the lowest quartile (HR, 2.33; 95% CI, 1.91-2.84). We concluded that circulating concentrations of sEng seem to be a suitable marker to assess the severity of preeclampsia and are associated with increased risk of adverse outcomes.

Uterine and ovary blood flow after uterine desarterialization / Efectos de la desarterialización uterina en el flujo sanguíneo uterino y ovárico

Background: The aim of this article is to compare the effect of uterine desarterialization (UD) and hypogastric arteries ligature (HAL) in uterine and ovarian blood flow indirectly measured with the pulsatility index (PI). Methods: Women in which UD or HAL was carried out for obstetric hemorrhage control were studied. Control group were puerperal women in which no UD or HAL was carried out. In all them uterine and ovarian blood flow was evaluated with the PI measured with Doppler ultrasound at 48 hours, 15 days and at 6 weeks after the procedure. Mann-Whitney U test was used for comparison between the groups and Wilcoxon test for comparisons inside each group. Results: Thirteen patients with UD, 11 with HAL and 10 without any procedure were studied. Uterine arteries PI, was significantly greater at 48 hr and at 15 days in the UD group and at 48 hr, 15 days and 6 weeks in the HAL group when compared with the control group. No differences were found in PI between UD and HAL groups. Ovarian PI was significantly greater in the groups with UD and HAL when compared with the control group at 48 hr, 15 days and 6 weeks, and lower in UD group when compared with HAL groups at 15 days and six weeks. Conclusions: Both procedures showed significant decrease in the uterine blood flow, but the ovarian flow was more restricted with HAL.

Introducción: el objetivo de este trabajo fue comparar el efecto de la desarterialización uterina (DAU) y la ligadura de arterias hipogástricas (LAH) en el flujo sanguíneo uterino y ovárico medido indirectamente con el índice de pulsatilidad (IP). Métodos: se estudiaron pacientes a las cuales se realizó DAU o LAH para control de hemorragia obstétrica y puérperas posparto (controles), en quienes no se había realizado procedimiento alguno. En todas se midió el IP en la arteria uterina y en el ovario con ultrasonido Doppler a las 48 horas, 15 días y 6 semanas de la cirugía o el parto. Para comparar los grupos entre sí se utilizó U de Mann-Whitney y al interior de cada grupo prueba de Wilcoxon. Resultados: se estudiaron 13 pacientes con DAU, 11 con LAH y 10 controles. El IP en las arterias uterinas fue mayor a las 48 horas y 15 días en el grupo con DAU y a las 48 horas, 15 días y seis semanas en el grupo con LAH, al compararlos con el control. No hubo diferencias en el IP entre el grupo con DAU y LAH. El IP ovárico fue significativamente mayor en los grupos con DAU y LAH al compararlo con el grupo control, a las 48 horas, 15 días y 6 semanas, y menor en el grupo con DAU al compararlo con el grupo con LAH a los 15 días y seis semanas. Conclusiones: ambos procedimientos disminuyeron significativamente el flujo sanguíneo uterino pero el flujo ovárico se restringió más con la LAH.

QTL analysis reveals quantitative resistant loci for Phytophthora infestans and Tecia solanivora in tetraploid potato (Solanum tuberosum L.).

Late blight and Guatemalan potato tuber moth caused by Phytophthora infestans and Tecia solanivora, respectively, are major phytosanitary problems on potato crops in Colombia and Ecuador. Hence, the development of resistant cultivars is an alternative for their control. However, breeding initiatives for durable resistance using molecular tools are limited due to the genome complexity and high heterozygosity in autotetraploid potatoes. To contribute to a better understanding of the genetic basis underlying the resistance to P. infestans and T. solanivora in potato, the aim of this study was to identify QTLs for resistance to P. infestans and T. solanivora using a F1 tetraploid potato segregant population for both traits. Ninety-four individuals comprised this population. Parent genotypes and their progeny were genotyped using SOLCAP 12K potato array. Forty-five percent of the markers were polymorphic. A genetic linkage map was built with a length of 968.4 cM and 1,287 SNPs showing good distribution across the genome. Severity and incidence were evaluated in two crop cycles for two years. QTL analysis revealed six QTLs linked to P. infestans, four of these related to previous QTLs reported, and two novel QTLs (qrAUDPC-3 and qrAUDPC-8). Fifteen QTLs were linked to T. solanivora, being qIPC-6 and qOPA-6.1, and qIPC-10 and qIPC-10.1 stable in two different trials. This study is one of the first to identify QTLs for T. solanivora. As the population employed is a breeding population, results will contribute significantly to breeding programs to select resistant plant material, especially in countries where P. infestans and T. solanivora limit potato production.

Lower circulating angiotensin II levels are related to the severity of preeclampsia and its risk as disclosed by a specific bioassay.

Preeclampsia is characterized by an increased sensitivity to angiotensin II (Ang II). We herein assessed whether serum Ang II levels measured by a new developed bioassay are associated with preeclampsia, its severity, and the risk for developing this disease.Using a cross-sectional design, we studied 90 pregnant women (30 healthy pregnant and 60 with preeclampsia [30 with- and 30 without severe features]). We also used a nested case-control study with 30 women who eventually developed preeclampsia and 31 normotensive controls. Serum samples were collected at diagnosis of preeclampsia or at 4-week intervals (from weeks 12th to 36th). Ang II was measured using a bioassay.At diagnosis of preeclampsia, serum Ang II concentrations were significantly lower in preeclampsia without and with severe features (P = .001 and P < .001, respectively) than in healthy pregnancy. In addition, Ang II was different in preeclampsia with severe features than in those without severe features (P = .048). Women who subsequently developed preeclampsia had lower Ang II levels than women with normal pregnancies, and these changes became significant at 24 weeks onward. The risk to developing preeclampsia was higher among women with Ang II concentration values in the lowest quartile of the control distribution from 12 weeks onward (odds ratio ranging from 3.8 [95% CI 1.3-11.1] to 6.5 [95% CI 1.6-26.9]).We concluded that concentrations of Ang II are markedly diminished at diagnosis of preeclampsia and are closely associated with the severity of disease. Changes in circulating levels of Ang II precede the clinical presentation of preeclampsia.

Evolution of Bacillus thuringiensis Cry toxins insecticidal activity.

Insecticidal Cry proteins produced by Bacillus thuringiensis are use worldwide in transgenic crops for efficient pest control. Among the family of Cry toxins, the three domain Cry family is the better characterized regarding their natural evolution leading to a large number of Cry proteins with similar structure, mode of action but different insect specificity. Also, this group is the better characterized regarding the study of their mode of action and the molecular basis of insect specificity. In this review we discuss how Cry toxins have evolved insect specificity in nature and analyse several cases of improvement of Cry toxin action by genetic engineering, some of these examples are currently used in transgenic crops. We believe that the success in the improvement of insecticidal activity by genetic evolution of Cry toxins will depend on the knowledge of the rate-limiting steps of Cry toxicity in different insect pests, the mapping of the specificity binding regions in the Cry toxins, as well as the improvement of mutagenesis strategies and selection procedures.

[Microorganisms in the biological control of insects and phytopathogens]. / Los microorganismos en el control biológico de insectos y fitopatógenos.

In this review we cover the biological control of insects, bacteria and fungus that affect different crops. Using different microorganism as bacteria viruses and fungus can do the biological control of these important problems. In this work we describe with detail the mode of action of the different microorganisms used to control insects and plant diseases. We also present novel strategies to improve the efficiency of these microorganisms against their targets and we present the development and production of several formulations to be used in the fields for the biological control of some plant problems.

BgK, a disulfide-containing sea anemone toxin blocking K+ channels, can be produced in Escherichia coli cytoplasm as a functional tagged protein.

BgK, a sea anemone peptide consisting of 37 amino acid residues and 3 disulfide bonds, blocks voltage-gated potassium (Kv1) channels. Here, we report a method for producing tagged BgK in Escherichia coli, as a soluble cytoplasmic protein. First, using peptidic synthesis, we show that addition of a 15 residue peptide (S.Tag) at the BgK C-terminus does not affect its biological activity. Then, a synthetic DNA sequence encoding BgK was constructed and cloned to produce a BgK-S.Tag hybrid in the cytoplasm of E. coli. The presence of S.Tag did not only facilitate detection, quantification, and purification of the recombinant protein, but also increased the production yield by more than two orders of magnitude. Moreover, use of an E. coli OrigamiB(DE3)pLacI strain also increased production; up to 5.8-7.5mg of BgK-S.Tag or mutated BgK(F6A)-S.Tag was produced per liter of culture and could be functionally characterized in crude extracts. Using a two-step purification procedure (affinity chromatography and RP-HPLC), we obtained 1.8-2.8mg of purified recombinant protein per liter of culture. The recombinant peptides displayed functional properties similar to those of native BgK or BgK(F6A).