Strain Improvement Research Articles

Abstract 14853: Effects of Yearlong High Intensity Aerobic Exercise on Reducing Left Atrial Epicardial Adipose Tissue

Background: Left atrial epicardial adipose tissue (LA EAT) is often elevated in patients with heart failure and has been linked to abnormal atrial function and increased risk for atrial fibrillation. Whether LA EAT is potentially modifiable is unknown. We tested the hypothesis that one year of high intensity interval training (HIIT) would reduce LA EAT area and in turn be associated with improved atrial function in an obese cohort at risk for developing heart failure with preserved ejection fraction (HFpEF). Methods: Middle-aged obese adults (n = 80, age 40-55 yrs) enriched for increased HFpEF risk (N-terminal pro-B-type natriuretic peptide >40 pg/mL or high-sensitivity cardiac troponin T >0.6 pg/mL; visceral fat >2kg) were randomized to one year of HIIT or attention control. Outcome variables included LA EAT area and LA strain. LA EAT area was quantified through tracings of anterior, posterior, and lateral EAT depots in long axis views on cardiac MRI. LA strain was measured with MRI feature tracking as reservoir strain during left ventricular (LV) systole, conduit strain during early LV diastole, and contractile strain during late LV diastole. Results: Fifty-three participants completed the study. There was no difference in LA EAT area after one year in either the HIIT group (n = 26) or controls (n = 27); difference in mean = -0.17 cm 2 , 95% CI = -0.93 to 0.59, p = 0.66. However, amongst all participants, reduction in LA EAT was associated with improvement in LA reservoir strain (r = -0.50, 95% CI = -0.68 to -0.26, p < 0.001) and LA conduit strain (r = 0.51, 95% CI = 0.27 to 0.68, p < 0.001) but not LA contractile strain (r = 0.15, 95% CI = -0.13 to 0.40, p = 0.298). Conclusions: One year of HIIT did not reduce LA EAT in at-risk obese patients. However, regardless of assignment, decreased LA EAT was associated with improved LA reservoir and conduit strain, suggesting efforts to reduce LA EAT may improve LA function in at-risk obese patients.

Abstract 16806: Transcatheter Edge-to-Edge Repair Lessens Atrial Fibrillation Burden by Ameliorating Left Atrial Strain in Moderate-to-Severe Mitral Regurgitation Patients

Introduction: trans-catheter edge-to-edge repair (TEER) represents a therapeutic possibility in patients with moderate-severe mitral regurgitation (MR) considered at high surgical risk. Only in recent years, it has been realized that left atrial (LA) function plays a prognostic role in these patients. Hypothesis: since atrial fibrillation (AF) depends in part on LA geometry, we considered that two-dimensional speckle-tracking-echocardiography analysis could predict AF burden. Aim: we therefore evaluated the AF occurrence long term after TEER. Methods: one hundred nine patients treated by TEER between February ‘15 and April ’22 underwent reservoir (R_s), conduct (D_s), and contractile (C_s) evaluations strains before and 1,6,12 months after TEER. Cardiac rhythm was monitored through 24 hours Holter-ECG or previously implanted cardiac devices, when available. Statistical analysis was performed with SPSS. Comparisons were carried out by ANOVA and MANOVA. Results: to the permanent AF group (n=35), no paroxysmal (N=15), nor persistent (N=8) case was added during follow-up after TEER. Among the sinus rhythm (N=51) group, one episode of atrial tachyarrhythmia was found at device interrogation and one patient developed paroxysmal AF (2/51; 3,9%). Significant improvements in total cohort were observed at 12 months follow-up for R_s (from 10,77±5,74% to 16,28±6,93%; p<0,0001), D_s (from -6,72±4,44% to -9,73±4,48%; p=0,0003) and C_s (from -5,21±5,11% to 7,72±5,4%; p=0,0184) compared to baseline. AF burden in paroxysmal AF (baseline: 9,2±4,7 hours, follow-up: 5,8±4,2 hours; p<0,001) was significantly reduced as well as ventricular rate (baseline 88±14 bpm; 12 months 76±13 bpm; p<0,001) in permanent AF group. Conclusions: MR reduction following TEER dictates positive LA remodelling and significant improvement of LA strain. Overall, the impact on LA geometry contributed to lessen incidence and burden of AF.

Achieving excellent mechanical properties in a dual-phase FeCrNi medium entropy alloy through athermal transformations and dislocation structures

In this study, a face-centered cubic (FCC) + body-centered cubic (BCC) dual-phase Fe40Cr40Ni20 (at.%) medium-entropy alloy (MEA) with outstanding mechanical properties was developed. Deformation and strain-hardening mechanisms of the MEA were investigated using a transmission electron microscope. In the FCC phase, dislocation slip was the main deformation mechanism, and twinning appeared at the high-stress stage. Dislocation tangle induced by multi-slip positively contributed to the improvement of strain hardening ability. In the BCC phase, deformation mainly depended on dislocation slip, stress-induced martensitic transformation, and twinning. ω particles resulting from martensitic transformation strongly inhibited dislocation motion. Deformation twins and dislocation structures enhanced the strain-hardening ability by reducing the dislocation mean free path. The BCC/FCC interface also contributed to strain hardening ability by hindering the dislocation movement. The combined action of multiple mechanisms led to the high strain-hardening rate of the MEA.

A novel high-performance coating with hybrid nanofiller reinforcement for superior self-cleaning, anti-icing, and corrosion resistance properties

A novel self-cleaning superamphiphobic nanocomposite coating with excellent corrosion protection, anti-icing, and mechanical properties has been developed through the integration of hybrid graphene nanoplate (GNP) and silica nanoparticle (NS) reinforcement, coupled with surface modification using fluorinated particles and polydimethylsiloxane (PDMS). The GNP/NS hybrid nanofiller imparts superior corrosion barrier performance and mechanical strength to the coating. The surface modification led to impressive contact angles of 168° for water and 150° for hexadecane. While sliding angle consistently displayed less than 10° for both fluids, signifying the coating's exceptional superamphiphobic characteristics. The coating demonstrates exceptional anti-icing performance, with significantly delayed ice formation and reduced ice adhesion. Moreover, the coating exhibits remarkable stability and durability, even after long-term exposure to corrosive and harsh weathering environments. Electrochemical impedance spectroscopy (EIS) measurements confirmed the coating's superior corrosion resistance; the impedance plot of developed coating remained unchanged and exceeded 1010 Ω/cm2 across various exposure durations, whereas the neat epoxy started with a lower impedance value that progressively diminished over the exposure period. Tensile tests revealed a 75% increase in tensile strength, 63% improvement in failure strain, and an 11% increase in Young's modulus compared to the neat epoxy. Additionally, to comprehensively elucidate the mechanisms underpinning the developed nanocomposite coating, this study utilized a range of advanced analytical methods, including SEM, EDX, XRD, FTIR, and hardness tests. The developed nanocomposite coating shows promising potential as a reliable, long-lasting protective solution for metal structures in civil, mechanical, and aerospace engineering applications.

Construction of a Compact Array of Microplasma Jet Devices and Its Application for Random Mutagenesis of Rhodosporidium toruloides.

A small and efficient DNA mutation-inducing machine was constructed with an array of microplasma jet devices (7 × 1) that can be operated at atmospheric pressure for microbial mutagenesis. Using this machine, we report disruption of a plasmid DNA and generation of mutants of an oleaginous yeast Rhodosporidium toruloides. Specifically, a compact-sized microplasma channel (25 × 20 × 2 mm3) capable of generating an electron density of greater than 1013 cm-3 was constructed to produce reactive species (N2*, N2+, O, OH, and Hα) under helium atmospheric conditions to induce DNA mutagenesis. The length of microplasma channels in the device played a critical role in augmenting both the volume of plasma and the concentration of reactive species. First, we confirmed that microplasma treatment can linearize a plasmid by creating nicks in vitro. Second, we treated R. toruloides cells with a jet device containing 7 microchannels for 5 min; 94.8% of the treated cells were killed, and 0.44% of surviving cells showed different colony colors as compared to their parental colony. Microplasma-based DNA mutation is energy-efficient and can be a safe alternative for inducing mutations compared to conventional methods using toxic mutagens. This compact and scalable device is amenable for industrial strain improvement involving large-scale mutagenesis.

Impact of chronic obstructive pulmonary disease on right ventricular function and remodeling after aortic valve replacement

BackgroundBoth chronic obstructive pulmonary disease (COPD) and right ventricular (RV) dysfunction are common factors that have been associated with poor prognosis after aortic valve replacement (AVR). Since there is still uncertainty about the impact of COPD on RV function and dilatation in patients undergoing AVR, we sought to explore RV function and remodeling in the presence and absence of COPD as well as their prognostic implications. MethodsPatients who received surgical or transcatheter AVR due to severe AS were screened for COPD. Demographic and clinical data were collected at baseline while echocardiographic measurements were performed at baseline and 1 year after AVR. The study end-point was all-cause mortality. ResultsIn total 275 patients were included, with 90 (33%) patients having COPD. At 1-year follow-up, mild worsening of tricuspid annular planar systolic excursion and RV dilatation were observed in patients without COPD, while there were significant improvements in RV longitudinal strain, RV wall thickness but dilatation of RV outflow tract distal dimension in the COPD group compared to the baseline. On multivariable analysis, the presence of COPD provided significant incremental prognostic value over RV dysfunction and remodeling. ConclusionsAt 1-year after AVR, RV function and dimensions mildly deteriorated in non-COPD group whereas COPD group received significant benefit of AVR in terms of RV function and hypertrophy. COPD was independently associated with >2-fold all-cause mortality and had incremental prognostic value over RV dysfunction and remodeling.

Overexpression of kojR and the entire koj gene cluster affect the kojic acid synthesis in Aspergillus oryzae 3.042

Kojic acid (KA), a fungal secondary metabolite, has various applications in the cosmetics, pharmaceutical, and food industries. Aspergillus oryzae, the primary strain, has been identified as a koj gene cluster positively responsible for KA biosynthesis. In this study, we obtained transformants T58 and T31, which overexpressed either solo kojR or the entire koj gene cluster, respectively. These transformants exhibited peak KA production on the 5th day of shake flask fermentation, with 32.5 g/L and 26.57 g/L that 324.28 % and 246.87 % higher than the control strain with 7.64 g/L, respectively. Morphological analysis revealed that the highly productive KA strains had reduced conidial production but increased antioxidant capacity. The qRT-PCR analysis revealed that relative expression levels of kojR in the transformants were remarkably higher that the primary cause for the increased KA yield. Moreover, the high expression of kojR could also influence the expression of the key enzymes involved in the KA biosynthesis process, such as glucose dehydrogenase and gluconate dehydrogenase. These findings can assist in discovering more about how the koj gene cluster in A. oryzae influences its growth and KA production. And provides valuable insights into facilitating strain improvement and benefits for the future.

Development of a CRISPR/Cas9D10A Nickase (nCas9)-Mediated Genome Editing Tool in Streptomyces.

Streptomycetes have a strong ability to produce a vast array of bioactive natural products (NPs) widely used in agriculture and veterinary/human medicine. The recently developed CRISPR/Cas9-based genome editing tools have greatly facilitated strain improvement for target NP overproduction as well as novel NP discovery in Streptomyces. However, CRISPR/Cas9 shows high toxicity to the host, limiting its application in many Streptomyces strains with a low DNA transformation efficiency. In this study, we developed a low-toxicity CRISPR/Cas9D10A nickase (nCas9)-based genome editing tool in the model strain Streptomyces coelicolor M145. We showed that in the presence of both targeting sgRNA and Cas proteins, utilization of nCas9 instead of Cas9 significantly reduced the toxicity to the host and greatly enhanced cell survival. Using this tool, we achieved deletion of single genes and gene clusters with efficiencies of 87-100 and 63-87%, and simultaneous deletion of two genes or gene clusters with efficiencies of 47 and 43%, respectively. The editing efficiency of nCas9 is comparable to that of the Cas9-mediated editing tool. Finally, the nCas9-based editing tool was successfully applied for genome editing in the industrial rapamycin-producing strain Streptomyces rapamycinicus, in which CRISPR/Cas9 cannot work well. We achieved the deletion of three tested genes with an efficiency of 27.2-30%. Collectively, the CRISPR/nCas9-based editing tool offers a convenient and efficient genetic modification system for the engineering of streptomycetes, particularly those with low DNA transformation efficiency.

Contribution of endophytes towards improving plant bioactive metabolites: a rescue option against red-taping of medicinal plants.

Medicinal plants remain a valuable source for natural drug bioprospecting owing to their multi-target spectrum. However, their use as raw materials for novel drug synthesis has been greatly limited by unsustainable harvesting leading to decimation of their wild populations coupled with inherent low concentrations of constituent secondary metabolites per unit mass. Thus, adding value to the medicinal plants research dynamics calls for adequate attention. In light of this, medicinal plants harbour endophytes which are believed to be contributing towards the host plant survival and bioactive metabolites through series of physiological interference. Stimulating secondary metabolite production in medicinal plants by using endophytes as plant growth regulators has been demonstrated to be one of the most effective methods for increasing metabolite syntheses. Use of endophytes as plant growth promotors could help to ensure continuous supply of medicinal plants, and mitigate issues with fear of extinction. Endophytes minimize heavy metal toxicity in medicinal plants. It has been hypothesized that when medicinal plants are exposed to harsh conditions, associated endophytes are the primary signalling channels that induce defensive reactions. Endophytes go through different biochemical processes which lead to activation of defence mechanisms in the host plants. Thus, through signal transduction pathways, endophytic microorganisms influence genes involved in the generation of secondary metabolites by plant cells. Additionally, elucidating the role of gene clusters in production of secondary metabolites could expose factors associated with low secondary metabolites by medicinal plants. Promising endophyte strains can be manipulated for enhanced production of metabolites, hence, better probability of novel bioactive metabolites through strain improvement, mutagenesis, co-cultivation, and media adjustment.

Adaptive laboratory evolution empowers lipids and biomass overproduction in Chlorella vulgaris for environmental applications

Microalgal strain improvement with commercial features is needed to generate green biological feedstock to produce lipids for bioenergy. Hence, improving algal strain with enhanced lipid content without hindering cellular physiological parameters is pivotal for commercial applications of microalgae. In this report, we demonstrated the adaptive laboratory evolution (ALE) by hypersaline conditions to improve the algal strains for increasing the lipid overproduction capacity of Chlorella vulgaris for environmental applications. The evolved strains (namely E2 and E2.5) without notable impairment in general physiological parameters were scrutinized after 35 cycles. Conventional gravimetric lipid analysis showed that total lipid accumulation was hiked by 2.2-fold in the ALE strains compared to the parental strains. Confocal observation of algal cells stained with Nile-red showed that the abundance of lipid droplets was higher in the evolved strains without any apparent morphological aberrations. Furthermore, evolved strains displayed notable antioxidant potential than the control cells. Interestingly, carbohydrates and protein content were significantly decreased in the evolved cells, indicating that carbon flux was redirected into lipogenesis in the evolved cells. Altogether, our findings demonstrated a potential and feasible strategy for microalgal strain improvement for simultaneous lipids and biomass hyperaccumulation.

Braiding Polythene Lay‐Flat Tube into Cotton Threads for Artificial Muscle Actuation

In wearable robotics, soft actuation principles have been increasingly explored and tested due to their safety and comfort in human–robot interactions. Herein, a braided flat‐tube artificial muscle (BFAM) is presented. BFAMs are fabricated by braiding cotton threads together with an inexpensive lay‐flat tube (LFT) in a specific conform‐to‐LFT weaving method. They generate uniaxial contractions when powered by compressed fluids. The basic structure and working mechanism of the proposed BFAM are explained, and a quasistatic model is also developed. A comparison with other fluidic driven soft actuators is made and tabulated. Based on experimental studies, the proposed BFAM can contract close to 30% and yield force outputs more than 150 times their weight at an air pressure of 0.12 MPa. BFAM can be braided with multiple layers of flat tube without large increase of size. Experimental studies have shown that more layers of flat tube give a larger strain and output force up to four layers, beyond which layer increase does not yield visible improvement in strain and output force. Finally, potential applications of BFAM to arm joint actuations are illustrated to show its easy fitting to wearable robotics.

The Effect of Mutagenesis on the Production of Mycelia Growth of Auricularia Species in Nigeria

Auricularia species is a jelly-like edible mushroom belonging to the class Basidiomycete, Family Auriculariacea. It has many medicinal properties and is widely consumed in Nigeria. Not much research effort appears to have been conducted on its domestication and commercial production in Nigeria. This study evaluated the use of sawdust and rice bran as potential substrates for its cultivation. Two strains of Auricularia species were collected from the wild and identified as Auricularia polytricha and Auricularia subglabra by genetic DNA extraction. Pure cultures of the species were screened for strain improvement by mutagenesis using UV light and ethyl methyl sulfonate mutagens. Spawn of the wild species and the mutants were produced using sorghum grain. The produced spawn was used for the production of the mushroom fruit bodies using sawdust supplemented with rice bran. The biological efficiencies of both wild and mutant were 197% and 90% respectively. A combination of sawdust and rice bran supported the growth of both species of Auricularia. The Rate of spawn running during spawn production was also negatively affected by mutagenesis in mutants.

Domestication in dry-cured meat Penicillium fungi: Convergent specific phenotypes and horizontal gene transfers without strong genetic subdivision.

Some fungi have been domesticated for food production, with genetic differentiation between populations from food and wild environments, and food populations often acquiring beneficial traits through horizontal gene transfers (HGTs). Studying their adaptation to human-made substrates is of fundamental and applied importance for understanding adaptation processes and for further strain improvement. We studied here the population structures and phenotypes of two distantly related Penicillium species used for dry-cured meat production, P. nalgiovense, the most common species in the dry-cured meat food industry, and P. salamii, used locally by farms. Both species displayed low genetic diversity, lacking differentiation between strains isolated from dry-cured meat and those from other environments. Nevertheless, the strains collected from dry-cured meat within each species displayed slower proteolysis and lipolysis than their wild conspecifics, and those of P. nalgiovense were whiter. Phenotypically, the non-dry-cured meat strains were more similar to their sister species than to their conspecific dry-cured meat strains, indicating an evolution of specific phenotypes in dry-cured meat strains. A comparison of available Penicillium genomes from various environments revealed HGTs, particularly between P. nalgiovense and P. salamii (representing almost 1.5 Mb of cumulative length). HGTs additionally involved P. biforme, also found in dry-cured meat products. We further detected positive selection based on amino acid changes. Our findings suggest that selection by humans has shaped the P. salamii and P. nalgiovense populations used for dry-cured meat production, which constitutes domestication. Several genetic and phenotypic changes were similar in P. salamii, P. nalgiovense and P. biforme, indicating convergent adaptation to the same human-made environment. Our findings have implications for fundamental knowledge on adaptation and for the food industry: the discovery of different phenotypes and of two mating types paves the way for strain improvement by conventional breeding, to elucidate the genomic bases of beneficial phenotypes and to generate diversity.

Effect of polyurethane matrix and steel fiber in combination with glass fiber or basalt fiber on the properties of hybrid composite laminates

Abstract Polyurethane is a versatile polymer with a high degree of toughness and ductility used in a wide variety of applications. In this study, two-part thermoset polyurethane was used as a matrix material to prepare hybrid and non-hybrid composites. Hybrid laminates were prepared by combining either glass fiber or basalt fibers with steel fibers. The mechanical properties of prepared composite specimens were characterized and scanning electron microscope (SEM) observation was performed around the fracture region of the tested specimens. The results revealed a significant increment in tensile strength, and flexural strength in BS1-PU (8 layers of basalt-1 layer of steel) hybrid laminate by 357.74 % and 64.59 %, respectively, compared to steel fibers reinforced polyurethane composites. Furthermore, GS4-PU hybrid composite (5 layers of glass-4 layers of steel) achieved an improvement in tensile strain by 12.07 %, flexural strain by 25.32 %, and absorbed energy by 18.21 %, compared to glass fibers reinforced polyurethane composite. Moreover, the SEM observations revealed that the replacement of some basalt and glass layers with steel layers leads to a positive hybridization effect of the overall produced hybrid composites.

Preparation of graphene oxide enhanced magnetic composite hydrogels by one‐pot method for selective adsorption

AbstractMagnetic composite hydrogels exhibit promising prospects for diverse applications, but their mechanical properties impose limitations on their further advancement. In this study, a novel approach is proposed to directly prepare magnetic composite hydrogels utilizing nanoferroferric oxide, aiming to replace the existing preparation method. Meanwhile, graphene oxide (GO) is introduced into magnetic composite hydrogels to enhance their mechanical characteristics. By employing ammonium citrate (AC) as a dispersant, the dispersion of ferroferric oxide magnetic nanoparticles at a concentration of 40 mg/mL is achieved, enabling their coexistence with GO for the preparation of magnetic composite hydrogels. Notably, the incorporation of 3 mg/mL GO and 40 mg/mL magnetic nanoparticles in polyacrylamide (PAM) hydrogel yields remarkable improvements in maximum stress and strain, reaching 148 kPa and 496%, respectively. In contrast, magnetic composite hydrogels without GO exhibit lower values of 46.5 kPa and 351%. The presence of magnetic nanoparticles imparts magnetism to the hydrogel, with higher concentrations of magnetic nanoparticles leading to increased magnetism. Moreover, the presence of AC and GO renders the hydrogels electronegative, thereby endowing them with selective adsorption capabilities. In summary, the magnetic composite hydrogels prepared by one‐pot method have good mechanical properties and selective adsorption capacity, and have good application potential.

Electrocardiographic Markers of Adverse Left Ventricular Remodeling and Myocardial Fibrosis in Severe Aortic Stenosis.

The optimal timing for aortic valve replacement (AVR) in aortic stenosis (AS) is still controversial and may be guided by markers of adverse left ventricular (LV) remodeling. We aim to assess electrocardiographic (ECG) strain in relation to LV remodeling and myocardial fibrosis. 83 severe AS patients underwent surgical AVR, with preoperative 12-lead ECG, cardiovascular magnetic resonance with T1 mapping and echocardiography with global longitudinal strain analysis. Collagen volume fraction (CVF) was measured in myocardial biopsies sampled during AVR. Patients with ECG strain had more severe AS, more advanced LV remodeling and evidence of heart failure. Patients with ECG strain had more diffuse fibrosis, as evident by higher mean native T1 values (974.8 ± 34 ms vs. 946.5 ± 28 ms, p < 0.001). ECG strain was the only predictor of increased LV mass index on multivariate regression analysis (OR = 7.10, 95% CI 1.46-34.48, p = 0.02). Patients with persistent ECG strain at 1 year following AVR had more advanced LV remodeling and more histological fibrosis (CVF 12.5% vs. 7.3%, p = 0.009) at baseline assessment. Therefore, ECG strain is a marker of adverse LV remodeling and interstitial myocardial fibrosis. Lack of improvement in ECG strain following AVR indicates more advanced baseline LV injury and higher levels of myocardial fibrosis.

Dicarboxylic Amino Acid Permease 7219 Regulates Fruiting Body Type of Auricularia heimuer.

Auricularia heimuer is a widely cultivated jelly mushroom. The fruiting bodies are categorized into cluster and chrysanthemum types. With changing consumer demands and the need to reduce bio-waste, the demand for clustered fruiting bodies is increasing. Therefore, gene mining for fruiting body types is a matter of urgency. We determined that the A. heimuer locus for fruiting body type was located at one end of the genetic linkage map. The locus was localized between the markers D23860 and D389 by increasing the density of the genetic linkage map. BlastN alignment showed that the marker SCL-18 was also located between D23860 and D389, and a total of 25 coding genes were annotated within this interval. Through parental transcriptome analysis and qRT-PCR verification, the locus g7219 was identified as the gene controlling the fruiting body type. A single-nucleotide substitution in the TATA box of g7219 was detected between the parents. By PCR amplification of the promoter region of g7219, the TATA-box sequences of the cluster- and chrysanthemum-type strains were found to be CATAAAA and TATAAAA, respectively. This study provides a foundation for the breeding of fruiting body types and strain improvement of A. heimuer.

Profiling of the β-glucosidases identified in the genome of Penicillium funiculosum: insights from genomics, transcriptomics, proteomics, and homology-modeling studies.

The enzymatic conversion of lignocellulosic biomass to bioethanol depends on efficient enzyme systems with β-glucosidase as one of the key components. In this study, we performed in-depth profiling of the various β-glucosidases present in the genome of the hypercellulolytic fungus Penicillium funiculosum using genomics, transcriptomics, proteomics, and molecular dynamics simulation approaches. Of the eight β-glucosidase genes identified in the P. funiculosum genome, three were predicted to be extracellular based on signal peptide prediction and abundance in the secretome. Among the three secreted β-glucosidases, two belonged to the GH3 family and one belonged to the GH1 family. Homology models of these proteins predicted a deep and narrow active site for the GH3 β-glucosidases (PfBgl3A and PfBgl3B) and a shallow open active site for the GH1 β-glucosidase (PfBgl1A). The enzymatic assays indicated that P. funiculosum-secreted proteins showed high β-glucosidase activities with prominent bands on the 4-methylumbelliferyl β-D-glucopyranoside zymogram. To understand the contributory effects of each of the three secreted β-glucosidases (PfBgls), the corresponding gene was deleted separately, and the effect of the deletion on the β-glucosidase activity of the secretome was examined. Although not the most abundant, PfBgl3A was found to be one of the most important β-glucosidases, as evidenced by a 42% reduction in β-glucosidase activity in the ΔPfBgl3A strain. Our results advance the understanding of the genetic and biochemical nature of all β-glucosidases produced by P. funiculosum and pave the way to design a superior biocatalyst for the hydrolysis of lignocellulosic biomass. IMPORTANCE Commercially available cellulases are primarily produced from Trichoderma reesei. However, external supplementation of the cellulase cocktail from this host with exogenous β-glucosidase is often required to achieve the desired optimal saccharification of cellulosic feedstocks. This challenge has led to the exploration of other cellulase-producing strains. The nonmodel hypercellulolytic fungus Penicillium funiculosum has been studied in recent times and identified as a promising source of industrial cellulases mainly due to its ability to produce a balanced concoction of cellulolytic enzymes, including β-glucosidases. Various genetic interventions targeted at strain improvement for cellulase production have been performed; however, the β-glucosidases of this strain have remained largely understudied. This study, therefore, reports profiling of all eight β-glucosidases of P. funiculosum via molecular and computational approaches. The results of this study provide useful insights that will establish the background for future engineering strategies to transform this fungus into an industrial workhorse.

Evaluation of Saccharomyces cerevisiae Improved Strains Potential in the Bioethanol Production from Bagasse

Plant biomass can be utilized to produce bioethanol, because they are abundantly available in nature. The cost of ethanol production from lignocellulosic materials is relatively high with low yield. But this can be solved by strain improvement processes. This study is aimed at evaluate bioethanol production potential of improved strains of Saccharomyces cerevisiae developed through random mutagenesis. Bagasse was hydrolysed with 1% NaOH and 1.0M H2SO4 respectively for five days. The hydrolysed bagasse was saccharified using Aspergillus niger isolated from soil samples. Saccharomyces cerevisiae isolated from locally produced wines; sorghum (burukutu) oil palm wine (emu) and raphia palm wine (oguro) with the highest ethanol production (5.0g/ml) were used, and then treated with physical mutagen (ultraviolet light) and chemical mutagens (Acridine dye, Bromo acetaldehyde, dithiothreitol, Ketoconazole and Nitrous acid) respectively to develop mutant with high ethanol producing efficiency under varied operational parameters. Three mutant strains of Saccharomyces cerevisiae namely;- SUV, SCD and SCK produced higher volumes of ethanol (7.5 g/ml, 9.8 g/ml, 11.2 g/ml respectively). SCD and SCK were able to grow at 25% ethanol concentration indicating that they had higher ethanol tolerance ability than the other strains. The optimum temperature and pH for ethanol production by all the strains were 350C and 6.0 respectively. The improved strains of Saccharomyces cerevisiae developed through random mutation techniques had produced more ethanol from the bagasse than the wild-type.

Bending and free vibration analyses of CNTRC shell structures considering agglomeration effects with through-the-thickness stretch

The present work investigates an enhanced finite element model and numerical analysis to illustrate the agglomeration effect of Carbon Nanotubes (CNTs) on static and free vibration responses of reinforced composite plate and cylindrical panel shell. The developed model is based on the kinematics of the improved first-order-shear deformation theory (FSDT), assuming a parabolic variation of the transverse shear strains and fulfilling the zero circumstance of the transverse shear stresses at the extreme structure’ surfaces omitting the use of shear correction factors. The material properties of the nanocomposite are determined using a developed micromechanical model based on the Mori–Tanaka approach. The developed finite element formulation is based on three-dimensional constitutive equations without reduction involving the addition of one parameter of thickness change combined with the Enhanced Assumed Strain (EAS) method. Four enhancement models are established and discussed. In a first attempt, the improvement of the third bending strain using one or four parameters are presented. In a second attempt, the membrane strain is enhanced with four parameters. Due to lack of investigations on structural behavior of composite structures reinforced with agglomerated CNTs, new static and free vibration results for shell structures with three level of CNT agglomeration are examined. Parametric studies are here in developed to present the influences of the characteristic parameters on the structural behavior of the CNTRC shell in a new graphic way; such as the volume fraction and agglomeration of nanofibers, geometrical parameters, and boundary conditions. Based on numerical results, it is found that the agglomeration and distributions of the reinforcing fibers are really crucial and play a significant role on the static and vibrational performances of the structure.