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1.
Objectives
To analyze the anti-insect mechanism of viral pesticide AcMNPV-BmK IT(P10/PH) in the host Spodoptera frugiperda 9 (Sf9) cells.Results
Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV)- mediated expression of BmK IT, regulated by P10 protein promoter (P10) and polyhedrosis promoter (PH), promoted the replication of progeny virus in host Sf9 cells. AcMNPV-BmK IT(P10) could accelerate the budding process (or speed) of budded virus (BV) in Sf9 cells. The impact of AcMNPV-BmK IT(P10) on the nuclear polymerization of filamentous actin (F-actin) participated in regulating the accelerated budding process. Unexpectedly, both AcMNPV-BmK IT(P10) and AcMNPV-BmK IT(PH) delayed the nuclear polymerization of F-actin and promoted the clearance of F-actin in the nucleus. SfP53, an important apoptosis factor, was involved in the regulation of AcMNPV-BmK IT(P10/PH) in Sf9 cells. AcMNPV-BmK IT(P10/PH) could also delay and promote the nuclear recruitment of SfP53 after 27 h post infection (h p.i.).Conclusion
SfP53 and F-actin are the targets of viral pesticide AcMNPV-BmK IT (P10/PH) in host Sf9 cells, which provides the experimental basis for the development of recombinant baculovirus biopesticides.2.
Objectives
To analyze the mechanisms underlying the impact of recombinant Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV)-mediated BmK IT expression on the function of baculovirus GP64 envelope fusion protein and progeny virus production.Results
Viral propagation assay indicated that overexpression GP64 could promote replication of AcMNPV. AcMNPV-mediated expression of BmK IT also promoted replication of AcMNPV. Immunofluorescence analysis showed BmK IT, which was regulated by very early promoter IE1 in AcMNPV, could make the GP64 protein move to the cytomembrane soon after transfection. BmK IT, which is regulated by P10 protein promoter (P10) and polyhedrosis promoter (PH), could promote the expression of GP64.Conclusion
BmK IT, regulated by very early promoter IE1, P10 protein promoter (P10) and PH, accelerated the expression of GP64 protein, promoted its early cytomembrane localization and then triggered virus budding and progeny virus production.3.
Lifei Chen Chunling Ma Ruiming Wang Jianlou Yang Haijie Zheng 《Biotechnology letters》2016,38(10):1769-1774
Objectives
To improve 1,3-propanediol (1,3-PD) production and reduce byproduct concentration during the fermentation of Klebsiella pneumonia.Results
Klebsiella. pneumonia 2-1ΔldhA, K. pneumonia 2-1ΔaldH and K. pneumonia 2-1ΔldhAΔaldH mutant strains were obtained through deletion of the ldhA gene encoding lactate dehydrogenase required for lactate synthesis and the aldH gene encoding acetaldehyde dehydrogenase involved in the synthesis of ethanol. After fed-batch fermentation, the production of 1,3-PD from glycerol was enhanced and the concentrations of byproducts were reduced compared with the original strain K. pneumonia 2-1. The maximum yields of 1,3-PD were 85.7, 82.5 and 87.5 g/l in the respective mutant strains.Conclusion
Deletion of either aldH or ldhA promoted 1,3-PD production in K. pneumonia.4.
Jinxiang Zhu Qiaoyun Zhu Ruiqing Gong Qin Xu Menghao Cai Tianyi Jiang Xiangshan Zhou Mian Zhou Yuanxing Zhang 《Biotechnology letters》2018,40(9-10):1365-1376
Objective
Around one-fourth of the Komagataella phaffii genes encode hypothetical proteins with unknown functions. However, lack of powerful tools for genetic screening in K. phaffii significantly limits the functional analysis of these unknown genes. Transposon mutagenesis has been utilized as an insertional mutagenesis tool in many other organisms and would be extremely valuable if it could be applied in K. phaffii.Results
In this study, we investigated in K. phaffii the transposition activity and efficiency of piggyBac (PB) transposon, a DNA transposon from the cabbage looper moth Trichoplusia ni through the integrated-plasmid system. We also designed a binary-plasmid system which could generate stable mutants. Finally we evaluated the quality of this mutagenesis system by a simple screening for functional genes involved in K. phaffii carbon catabolite repression.Conclusions
Our results demonstrate that PB-mediated mutagenesis could be a feasible and useful tool for functional gene screening in K. phaffii.5.
Marie GB Hansen Mette Christoffersen Line R Thuesen Morten R Petersen Anders M Bojesen 《Acta veterinaria Scandinavica》2010,52(1):3
Background
Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum are able to infect horses. However, the extend to which Danish horses are infected and seroconvert due to these two bacteria is unknown. The aim of the present study was to evaluate the seroprevalence of B. burgdorferi sensu lato and A. phagocytophilum in Danish horses.Methods
A total of 390 blood samples collected from all major regions of Denmark and with a geographical distribution corresponding to the density of the Danish horse population were analyzed. All samples were examined for the presence of antibodies against B. burgdorferi sensu lato and A. phagocytophilum by the use of the SNAP®4DX ® ELISA test.Results
Overall, 29.0% of the horses were seropositive for B. burgdorferi sensu lato whereas 22.3% were seropositive for A. phagocytophilum.Conclusions
Antibodies against B burgdorferi sensu lato and A. phagocytophilum are commonly found among Danish horses thus showing that Danish horses are frequently infected by these organisms.6.
Korey J. Brownstein Mahmoud Gargouri William R. Folk David R. Gang 《Metabolomics : Official journal of the Metabolomic Society》2017,13(11):133
Introduction
Botanicals containing iridoid and phenylethanoid/phenylpropanoid glycosides are used worldwide for the treatment of inflammatory musculoskeletal conditions that are primary causes of human years lived with disability, such as arthritis and lower back pain.Objectives
We report the analysis of candidate anti-inflammatory metabolites of several endemic Scrophularia species and Verbascum thapsus used medicinally by peoples of North America.Methods
Leaves, stems, and roots were analyzed by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) and partial least squares-discriminant analysis (PLS-DA) was performed in MetaboAnalyst 3.0 after processing the datasets in Progenesis QI.Results
Comparison of the datasets revealed significant and differential accumulation of iridoid and phenylethanoid/phenylpropanoid glycosides in the tissues of the endemic Scrophularia species and Verbascum thapsus.Conclusions
Our investigation identified several species of pharmacological interest as good sources for harpagoside and other important anti-inflammatory metabolites.7.
Camila Gazolla Volpiano Bruno Brito Lisboa Jackson Freitas Brilhante São José Andreia Mara Rotta de Oliveira Anelise Beneduzi Luciane Maria Pereira Passaglia Luciano Kayser Vargas 《Plant and Soil》2018,432(1-2):229-243
Aims
To identify Rhizobium strains’ ability to biocontrol Sclerotium rolfsii, a fungus that causes serious damage to the common bean and other important crops, 78 previously isolated rhizobia from common bean were assessed.Methods
Dual cultures, volatiles, indole-acetic acid (IAA), siderophore production and 16S rRNA sequencing were employed to select strains for pot and field experiments.Results
Thirty-three antagonistic strains were detected in dual cultures, 16 of which were able to inhibit ≥84% fungus mycelial growth. Antagonistic strains produced up to 36.5 μg mL?1 of IAA, and a direct correlation was verified between IAA production and mycelium inhibition. SEMIA 460 inhibited 45% of mycelial growth through volatile compounds. 16S rRNA sequences confirmed strains as Rhizobium species. In pot condition, common bean plants grown on S. rolfsii-infested soil and inoculated with SEMIA 4032, 4077, 4088, 4080, 4085, or 439 presented less or no disease symptoms. The most efficient strains under field conditions, SEMIA 439 and 4088, decreased disease incidence by 18.3 and 14.5% of the S. rolfsii-infested control.Conclusions
Rhizobium strains could be strong antagonists towards S. rolfsii growth. SEMIA 4032, 4077, 4088, 4080, 4085, and 439 are effective in the biological control of the collar rot of the common bean.8.
Wenxuan Xu Yajuan Liu Yanxin Ye Meng Liu Laichuang Han Andong Song Liangwei Liu 《Biotechnology letters》2016,38(10):1739-1745
Objective
The 9_2 carbohydrate-binding module (C2) locates natively at the C-terminus of the GH10 thermophilic xylanase from Thermotoga marimita. When fused to the C-terminus, C2 improved thermostability of a GH11 xylanase (Xyn) from Aspergillus niger. However, a question is whether the C-terminal C2 would have a thermostabilizing effect when fused to the N-terminus of a catalytic module.Results
A chimeric enzyme, C2-Xyn, was created by step-extension PCR, cloned in pET21a(+), and expressed in E. coli BL21(DE3). The C2-Xyn exhibited a 2 °C higher optimal temperature, a 2.8-fold longer thermostability, and a 4.5-fold higher catalytic efficiency on beechwood xylan than the Xyn. The C2-Xyn exhibited a similar affinity for binding to beechwood xylan and a higher affinity for oat-spelt xylan than Xyn.Conclusion
C2 is a thermostabilizing carbohydrate-binding module and provides a model of fusion at an enzymatic terminus inconsistent with the modular natural terminal location.9.
Objectives
To characterize the genes responsible for ethanol utilization in Pichia pastoris.Results
ADH3 (XM_002491337) and ADH (FN392323) genes were disrupted in P. pastoris. The ADH3 mutant strain, MK115 (Δadh3), lost its ability to grow on minimal ethanol media but produced ethanol in minimal glucose medium. ADH3p was responsible for 92 % of total Adh enzyme activity in glucose media. The double knockout strain MK117 (Δadh3Δadh) also produced ethanol. The Adh activities of X33 and MK116 (Δadh) strains were not different. Thus, the ADH gene does not play a role in ethanol metabolism.Conclusion
The PpADH3 is the only gene responsible for consumption of ethanol in P. pastoris.10.
Objectives
To screen the phylogenetically-nearest members of Cellulosimicrobium cellulans for the production of cellulosome-like multienzyme complexes and extracellular β-xylosidase activity against 7-xylosyltaxanes and to get corresponding molecular insights.Results
Cellulosimicrobium (family Promicromonosporaceae) and all genera of the family Cellulomonadeceaec produced both cellulosome-like multienzyme complexes and extracellular β-xylosidase activity, while the other genera of the family Promicromonosporaceae did not. Multiple sequence alignments further indicated that hypothetic protein M768_06655 might be a possible key subunit.Conclusion
This is the first report that many actinobacteria species can produce cellulosome-like multienzyme complexes. The production of cellulosome-like complexes and the extracellular β-xylosidase activity against 7-xylosyltaxanes might be used to differentiate the genus Cellulosimicrobium from other genera of the family Promicromonosporaceae.11.
Background
For many years, yeast cell walls (YCW) and mannan oligosaccharides (MOS) have been used as alternatives to antibiotics and health feed additives to enhance the growth performance and health of food animals. In the present study, the inhibitory effects of YCWand MOS on the adhesion of enteropathogenic bacteria to intestinal epithelial cells were tested.Methods
YCW and MOS were extracted from Saccharomyces cerevisiae (XM 0315), and the morphology of YCW and MOS bound to pathogenic bacteria was observed by scanning electron microscopy (SEM). Real-time fluorescent quantitative PCR was used to quantitatively analyze the effects of YCW and MOS on the adhesion of Escherichia coli (CVCC3367) and Salmonella pullorum (CVCC520) to Caco-2 cells.Results
The results showed that YCW inhibited E. coli and S. pullorum binding to Caco-2 cells by 95% and 74%, respectively, whereas MOS prevented E. coli and S. pullorum binding by 67% and 50%, respectively.Conclusions
These data suggest that YCW has a stronger ability than MOS to inhibit pathogenic bacteria from adhering to Caco-2 cells in vitro.12.
Elaheh Sajadi Valiollah Babaipour Ali Asghar Deldar Bagher Yakhchali Seyed Safa-Ali Fatemi 《Biotechnology letters》2017,39(9):1395-1401
Objectives
To evaluate the crystallinity index of the cellulose produced by Escherichia coli Nissle 1917 after heterologous expression of the cellulose synthase subunit D (bcsD) gene of Gluconacetobacter xylinus BPR2001.Results
The bcsD gene of G. xylinus BPR2001 was expressed in E. coli and its protein product was visualized using SDS-PAGE. FTIR analysis showed that the crystallinity index of the cellulose produced by the recombinants was 0.84, which is 17% more than that of the wild type strain. The increased crystallinity index was also confirmed by X-ray diffraction analysis. The cellulose content was not changed significantly after over-expressing the bcsD.Conclusion
The bcsD gene can improve the crystalline structure of the bacterial cellulose but there is not any significant difference between the amounts of cellulose produced by the recombinant and wild type E. coli Nissle 1917.13.
F. Cheikhrouhou R. Guidara A. Masmoudi H. Trabelsi S. Neji H. Sellami F. Makni A. Ayadi 《Mycopathologia》2017,182(5-6):583-589
Aim
Malassezia folliculitis is caused by the invasion of hair follicles by large numbers of Malassezia cells. Several Malassezia researches still use cultures, morphology and biochemical techniques. The aim of this study was to identify Malassezia species isolated from patients diagnosed with folliculitis, at the Parasitology and Mycology Laboratory of Sfax University Hospital, and to explore the genetic diversity of Malassezia by using PCR-RFLP and PCR-sequencing targeting the rDNA region of the Malassezia genome.Patients and Methods
Specimens were taken from 27 patients with Malassezia folliculitis. For the molecular identification, PCR amplification of the 26S rDNAD1/D2 region was carried out using the Malup and Maldown primers and three restriction enzymes (BanI, MspI and HeaII) for RFLP analysis. The nucleotide sequences of each isolate were compared to those in the NCBI GenBank by using BLASTIN algorithm.Results
Three species of Malassezia yeasts were identified among the 31 Malassezia strains isolated: M. globosa (83.9%), M. sympodialis (12. 9%) and M. furfur (3.2%). The sequence analysis of M. globosa showed six genotypes.Conclusion
There is a high genotypic variability of M. globosa colonizing patients with folliculitis.14.
Andrelisse Arruda Viviane Castelo Branco Reis Vinícius Daniel Ferreira Batista Bruno Sahim Daher Luiza Cesca Piva Janice Lisboa De Marco Lidia Maria Pepe de Moraes Fernando Araripe Gonçalves Torres 《Biotechnology letters》2016,38(3):509-517
Objectives
To develop a new vector for constitutive expression in Pichia pastoris based on the endogenous glycolytic PGK1 promoter.Results
P. pastoris plasmids bearing at least 415 bp of PGK1 promoter sequences can be used to drive plasmid integration by addition at this locus without affecting cell growth. Based on this result, a new P. pastoris integrative vector, pPICK2, was constructed bearing some features that facilitate protein production in this yeast: a ~620 bp PGK1 promoter fragment with three options of restriction sites for plasmid linearization prior to yeast transformation: a codon-optimized α-factor secretion signal, a new polylinker, and the kan marker for vector propagation in bacteria and selection of yeast transformants.Conclusions
A new constitutive vector for P. pastoris represents an alternative platform for recombinant protein production and metabolic engineering purposes.15.
Lidiane de Oliveira Dayane Cristina Silva Santos Marilena dos Anjos Martins Maria Walderez Szeszs Marcia Souza Carvalho Melhem 《Current fungal infection reports》2017,11(4):158-162
Purpose of Review
We reviewed data on amphotericin B (AmB) tolerance among Cryptococcus neoformans/C. gattii species complex clinical isolates and present our results of large recent study on this issue.Recent Findings
The standard method to detect antifungal susceptibility is based on MIC (minimal inhibitory concentration) determination; however, there is no interpretative clinical breakpoints defined for antifungal agents against Cryptococcus species, and to date, there is no correlation of MIC and clinical response. The time-kill curves (TKC) methodology seems to provide some correlation with outcome and it could identify distinct profiles of AmB-fungicidal activity.Summary
Our group analyzed 83 human isolates from cryptococcosis cases. The isolates were tested by TKC and showed up 8.3% of tolerance to AmB. Importantly, the AmB-MIC was low for all isolates, including tolerant ones. Our findings are similar to other authors, due the ability of TKC to identify distinct AmB-fungicidal activity and detecting low susceptible isolates.16.
Pegah Amiri Azar Shahpiri Mohammad Ali Asadollahi Fariborz Momenbeik Siavash Partow 《Biotechnology letters》2016,38(3):503-508
Objectives
To engineer the yeast Saccharomyces cerevisiae for the heterologous production of linalool.Results
Expression of linalool synthase gene from Lavandula angustifolia enabled heterologous production of linalool in S. cerevisiae. Downregulation of ERG9 gene, that encodes squalene synthase, by replacing its native promoter with the repressible MET3 promoter in the presence of methionine resulted in accumulation of 78 µg linalool l?1 in the culture medium. This was more than twice that produced by the control strain. The highest linalool titer was obtained by combined repression of ERG9 and overexpression of tHMG1. The yeast strain harboring both modifications produced 95 μg linalool l?1.Conclusions
Although overexpression of tHMG1 and downregulation of ERG9 enhanced linalool titers threefold in the engineered yeast strain, alleviating linalool toxicity is necessary for further improvement of linalool biosynthesis in yeast.17.
Background
Salmonella spp. have been isolated from a wide range of wild animals. Opportunistic wild carnivores such as red foxes (Vulpes vulpes) and badgers (Meles meles) may act as environmental indicators or as potential sources of salmonellosis in humans. The present study characterizes Salmonella spp. isolated from the intestinal contents of hunted or dead red foxes (n?=?509) and badgers (n?=?17) in northern Italy.Findings
Thirty-one strains of Salmonella belonging to 3 Salmonella enterica subspecies were isolated. Fourteen different serovars of S. enterica subsp. enterica were identified, among which were serovars often associated with human illness.Conclusions
Wild opportunistic predators can influence the probability of infection of both domestic animals and humans through active shedding of the pathogen to the environment. The epidemiological role of wild carnivores in the spread of salmonellosis needs to be further studied.18.
Background
DNA double-strand breaks (DSBs) are highly cytotoxic and mutagenic. MRE11 plays an essential role in repairing DNA by cleaving broken ends through its 3′ to 5′ exonuclease and single-stranded DNA endonuclease activities.Methods
The present study aimed to in silico characterization and molecular modeling of MRE11 from Phoenix dactylifera L cv deglet nour (DnMRE11) by various bioinformatic approaches. To identify DnMRE11 cDNA, assembled contigs from our cDNA libraries were analysed using the Blast2GO2.8 program.Results
The DnMRE11 protein length was 726 amino acids. The results of HUMMER show that DnMRE11 is formed by three domains: the N-terminal core domain containing the nuclease and capping domains, the C-terminal half containing the DNA binding and coiled coil region. The structure of DnMRE11 is predicted using the Swiss-Model server, which contains the nuclease and capping domains. The obtained model was verified with the structure validation programs such as ProSA and QMEAN servers for reliability. Ligand binding studies using COACH indicated the interaction of DnMRE11 protein with two Mn2+ ions and dAMP. The ConSurf server predicted that residues of the active site and Nbs binding site have high conservation scores between plant species.Conclusions
A model structure of DnMRE11 was constructed and validated with various bioinformatics programs which suggested the predicted model to be satisfactory. Further validation studies were conducted by COACH analysis for active site ligand prediction, and revealed the presence of six ligands binding sites and two ligands (2 Mn2+ and dAMP).19.
Adones Sales Luana Ferreira Afonso Juliana Alves Americo Mauro de Freitas Rebelo Glaucia Maria Pastore Juliano Lemos Bicas 《Biotechnology letters》2018,40(3):561-567
Objective
To investigate the biocatalytic potential of Colletotrichum acutatum and Colletotrichum nymphaeae for monoterpene biotransformation.Results
C. acutatum and C. nymphaeae used limonene, α-pinene, β-pinene, farnesene, citronellol, linalool, geraniol, perillyl alcohol, and carveol as sole carbon and energy sources. Both species biotransformed limonene and linalool, accumulating limonene-1,2-diol and linalool oxides, respectively. α-Pinene was only biotransformed by C. nymphaeae producing campholenic aldehyde, pinanone and verbenone. The biotransformation of limonene by C. nymphaeae yielded 3.34–4.01 g limonene-1,2-diol l?1, depending on the substrate (R-(+)-limonene, S-(?)-limonene or citrus terpene (an agro-industrial by-product). This is among the highest concentrations already reported for this product.Conclusions
This is the first report on the biotransformation of these terpenes by Colletotrichum spp. and the biotransformation of limonene to limonene-1,2-diol possibly involves enzymes similar to those found in Grosmannia clavigera.20.
Yibin Zhuang Jingjie Jiang Huiping Bi Hua Yin Shaowei Liu Tao Liu 《Biotechnology letters》2016,38(4):619-627