Sequential Thermochemical Hydrolysis of Corncobs and Enzymatic Saccharification of the Whole Slurry Followed by Fermentation of Solubilized Sugars to Ethanol with the Ethanologenic Strain <Emphasis Type="Italic">Escherichia coli</Emphasis> MS04

Interest in the use of corncobs as feedstock for bioethanol production is growing. This study assesses the feasibility of sequential thermochemical diluted sulfuric acid pretreatment of corncobs at moderate temperature to hydrolyze the hemicellulosic fraction, followed by enzymatic hydrolysis of the whole slurry, and fermentation of the obtained syrup. The total sugar concentration after enzymatic hydrolysis was 85.21 g/l, i.e., 86 % of the sugars were liberated from the polymeric fractions, together with a low amount of furfural (0.26 g/l) and 4.01 g/l of acetic acid. The syrups, which contained 36.3, 40.9, 4.47, and 1.84 g/l of xylose, glucose, arabinose, and mannose, respectively, were fermented (pH 7, 37 °C, 150 rpm) to ethanol with the metabolically engineered acetate-tolerant Escherichia coli strain MS04 under non-aerated conditions, producing 35 g/l of ethanol in 18 h (1.94 g_EtOH/l/h), i.e., a conversion yield greater than 80 % of the theoretical value based on total sugars was obtained. Hence, using the procedures developed in this study, 288 l of ethanol can be produced per metric ton of dry corncobs. Strain MS04 can ferment sugars in the presence of acetate, and the amount of furans generated during the sequential thermochemical and enzymatic hydrolysis was low; hence, the detoxification step was avoided. The residual salts, acetic acid, and solubilized lignin present in the syrup did not interfere with the production of ethanol by E. coli MS04 and the results show that this strain can metabolize mixtures of glucose and xylose simultaneously.     

The Burden of Provider-Initiated Preterm Birth and Associated Factors: Evidence from the Brazilian Multicenter Study on Preterm Birth (EMIP)

Background

About 15 million children are born under 37 weeks of gestation worldwide. Prematurity is the leading cause of neonatal deaths and short/long term morbidities, entailing consequences not only for the individual, but also their family, health agencies, facilities and all community. The provider-initiated preterm birth is currently one of the most important obstetric conditions related to preterm births, particularly in middle and high income countries, thus decreasing the need for therapeutic preterm birth is essential to reduce global prematurity. Therefore detailed knowledge on the factors associated with provider-initiated preterm birth is essential for the efforts to reduce preterm birth rates and its consequences. In this current analysis we aimed to assess the proportion of provider-initiated (pi-PTB) among preterm births in Brazil and identify associated factors.

Methods and Findings

This is an analysis of a multicenter cross-sectional study with a nested case-control component called Brazilian Multicenter Study on Preterm Birth (EMIP). EMIP was conducted in 20 referral obstetric hospitals located in the three most populated of the five Brazilian regions. We analysed data of women with pi-PTB, defined as childbirth occurring at less than 37 weeks, medically indicated for maternal/fetal compromise or both; and women with term birth, childbirth at or after 37 weeks. Maternal, sociodemographic, obstetric, prenatal care, delivery, and postnatal characteristics were assessed as possible factors associated with pi-PTB, compared to term births. The overall prevalence of preterm births was 12.3%. Of these, approximately one-third of cases were initiated by the provider. Hypertensive disorders, placental abruption, and diabetes were the main maternal conditions leading to pi-PTB. Caesarean section was the most common mode of delivery. Chronic hypertension (OR 7.47; 95%CI 4.02–13.88), preeclampsia/eclampsia/HELLP syndrome (OR 15.35; 6.57–35.88), multiple pregnancy (OR 12.49; 4.86–32.05), and chronic diabetes (OR 5.24; 2.68–10.25) were the most significant factors independently associated with pi-PTB.

Conclusions

pi-PTB is responsible for about one-third of all preterm births, requiring special attention. The decision-making process relative to the choice of provider-initiated birth is complex, and many factors should be elucidated to improve strategies for its prevention, including evidence-based guidelines on proper management of the corresponding clinical conditions.     

Post‐dispersal seed recovery by animals: is it a plant‐ or an animal‐driven process?

The ability of animals to find and consume hoarded seeds (i.e. seed recovery) is a key stage within the seed dispersal process. However, the ecology of seed recovery is still poorly understood. Here, we analyze the factors controlling seed recovery by scatter‐hoarding rodents in an oak‐dominated temperate forest. We examined the relative importance of intrinsic seed traits (i.e. plant‐driven) and extrinsic seed factors (i.e. animal‐driven) on the probability of seed recovery. We found that seed recovery is mainly driven by extrinsic seed factors, mostly related to animal behavior (pilfering frequency, microsite preference, predation risk, burial depth and cache size). Important intrinsic traits such as seed size, seed quality and seed‐drop timing were, on average, of lower significance in the probability of seed recovery (2.8‐times less important than extrinsic factors); only seed quality was an important intrinsic trait. On the other hand, larger and nutritionally more valuable seeds showed a removal–recovery tradeoff as they enhance seed removal and hoarding (increasing dispersal quality) but also favour seed recovery (increasing predation). We find that other mechanisms beyond seed traits (e.g. masting) are needed to decrease seed recovery and, thus, increase seed survival. We conclude that, as seed recovery is mostly driven by animal behavioural factors, it substantially differs from other previous stages of the seed dispersal process that are more dependent on seed traits. We argue that seed recovery needs further attention to advance our understanding of the ecology of seed dispersal and the role of secondary dispersers as a selective force for seeds.     

Variation in Sexual Expression in Jacaratia mexicana (Caricaceae) in Southern Mexico: Frequency and Relative Seed Performance of Fruit-Producing Males

Dioecy, the segregation of male and female structures among individuals, is widespread in tropical plants, encompassing 10–30 percent of species in some sites. In many cases, interindividual sex separation is not complete, as individual plants, although nominally dioecious, may produce both types of reproductive structures. A common form of this sexual variation is the production of female structures in otherwise male individuals, commonly referred to as fruiting males. Here we report the existence of fruiting males in the dioecious tropical tree Jacaratia mexicana (Caricaceae). We show that fruiting males can constitute up to 45 percent of all males in some populations of a tropical forest in Southern Mexico. In order to determine the functional significance of fruiting males for the breeding system of J. mexicana , we compared the relative performance of male- and female-borne seeds. Our results show that seeds from fruiting males are three times less likely to germinate and survive than seeds from female trees. Based on relative seed fitness data, and sex ratios in natural populations, we estimate that 6–15 percent of the genes contributed by fruiting males to the next generation are transmitted via ovules, meaning that morphological variation in gender is at least partially accompanied by functional gender variation. Finally, our seed fitness estimates for fruiting males suggest that fruiting males will not replace female plants in natural populations.
Abstract in Spanish is available at http://www.blackwell-synergy.com/loi/btp .     

GROmaρs: A GROMACS-Based Toolset to Analyze Density Maps Derived from Molecular Dynamics Simulations

We introduce a computational toolset, named GROmaρs, to obtain and compare time-averaged density maps from molecular dynamics simulations. GROmaρs efficiently computes density maps by fast multi-Gaussian spreading of atomic densities onto a three-dimensional grid. It complements existing map-based tools by enabling spatial inspection of atomic average localization during the simulations. Most importantly, it allows the comparison between computed and reference maps (e.g., experimental) through calculation of difference maps and local and time-resolved global correlation. These comparison operations proved useful to quantitatively contrast perturbed and control simulation data sets and to examine how much biomolecular systems resemble both synthetic and experimental density maps. This was especially advantageous for multimolecule systems in which standard comparisons like RMSDs are difficult to compute. In addition, GROmaρs incorporates absolute and relative spatial free-energy estimates to provide an energetic picture of atomistic localization. This is an open-source GROMACS-based toolset, thus allowing for static or dynamic selection of atoms or even coarse-grained beads for the density calculation. Furthermore, masking of regions was implemented to speed up calculations and to facilitate the comparison with experimental maps. Beyond map comparison, GROmaρs provides a straightforward method to detect solvent cavities and average charge distribution in biomolecular systems. We employed all these functionalities to inspect the localization of lipid and water molecules in aquaporin systems, the binding of cholesterol to the G protein coupled chemokine receptor type 4, and the identification of permeation pathways through the dermicidin antimicrobial channel. Based on these examples, we anticipate a high applicability of GROmaρs for the analysis of molecular dynamics simulations and their comparison with experimentally determined densities.     

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...     

Schwannomas of the peroneal nerves: Clinical and functional results of surgical treatment

Objectives:Peroneal nerves Schwannomas are rare benign tumors. Literature is still poor of studies about clinical and functional outcomes after surgical treatment. We evaluated the pre-operative presentation of the disease and assessed clinical and functional outcomes after surgery.Methods:We collected all the cases of peroneal nerves’ neurinoma treated surgically between June 2016 and June 2020. We analyzed each patients’ personal data and carried out accurate clinical examinations before and after surgery. MRI was performed both pre-operatively and post-operatively.Results:We reported 9 cases of peroneal nerves schwannomas: five arising from the common peroneal nerve and four arising from the deep or superficial branches alone. Their mean size was 22.6 mm. Each patient showed sensation deficits before surgery; pre-operative MRC score was 4.2. Pre-Operative MSTS and LEFS scores were 23.6 and 64.4. Surgery was successful in each case. No local recurrence nor major complication occurred. Tumor size was significantly associated with both diagnostic delay and development of pre-operative deficits. Surgery was proven to be globally successful: post-operative evaluations highlighted a marked reduction of neurological signs and overall functional limitations.Conclusions:Surgical treatment at early stages of the disease represents a reliable and relatively safe therapeutic option.