Production of fatty acids by engineered Ogataea polymorpha / 生物工程学报

Fatty acids (FA) are widely used as feed stocks for the production of cosmetics, personal hygiene products, lubricants and biofuels. Ogataea polymorpha is considered as an ideal chassis for bio-manufacturing, due to its outstanding characteristics such as methylotroph, thermal-tolerance and wide substrate spectrum. In this study, we harnessed O. polymorpha for overproduction of fatty acids by engineering its fatty acid metabolism and optimizing the fermentation process. The engineered strain produced 1.86 g/L FAs under the optimized shake-flask conditions (37℃, pH 6.4, a C/N ratio of 120 and an OD600 of seed culture of 6-8). The fed-batch fermentation process was further optimized by using a dissolved oxygen (DO) control strategy. The C/N ratio of initial medium was 17.5, and the glucose medium with a C/N ratio of 120 was fed when the DO was higher than 30%. This operation resulted in a titer of 18.0 g/L FA, indicating the potential of using O. polymorpha as an efficient cell factory for the production of FA.

Production of high-purity recombinant human vascular endothelial growth factor (rhVEGF165) by Pichia pastoris / 生物工程学报

Vascular endothelial growth factor (VEGF165) is a highly specific vascular endothelial growth factor that can be used to treat many cardiovascular diseases. The development of anti-tumor drugs and disease detection reagents requires highly pure VEGF165 (at least 95% purity). To date, the methods for heterologous expression and purification of VEGF165 require multiple purification steps, but the product purity remains to be low. In this study, we optimized the codons of the human VEGF165 gene (vegf165) according to the yeast codon preference. Based on the Pichia pastoris BBPB vector, we used the Biobrick method to construct a five-copy rhVEGF165 recombinant expression vector using Pgap as the promoter. In addition, a histidine tag was added to the vector. Facilitated by the His tag and the heparin-binding domain of VEGF165, we were able to obtain highly pure rhVEGF165 (purity > 98%) protein using two-step affinity chromatography. The purified rhVEGF165 was biologically active, and reached a concentration of 0.45 mg/mL. The new design of the expression vector enables production of active and highly pure rhVEGF165 ) in a simplified purification process, the purity of the biologically active natural VEGF165 reached the highest reported to date.

Effect of E54 mutation of human secreted phospholipase A2 GIIE on substrate selectivity / 生物工程学报

Human secreted phospholipase A2 GIIE (hGIIE) is involved in inflammation and lipid metabolism due to its ability of hydrolyzing phospholipids. To reveal the mechanism of substrate head-group selectivity, we analyzed the effect of mutation of hGIIE on its activity and selectivity. hGIIE structural analysis showed that E54 might be related to its substrate head-group selectivity. According to the sequence alignment, E54 was mutated to alanine, phenylalanine, and lysine. Mutated genes were cloned and expressed in Pichia pastoris X33, and the enzymes with mutations were purified with 90% purity by ion exchange and molecular size exclusion chromatography. The enzymatic activities were determined by isothermal microthermal titration method. The Km of mutant E54K towards 1,2-dihexyl phosphate glycerol decreased by 0.39-fold compared with that of wild type hGIIE (WT), and the Km of E54F towards 1,2-dihexanoyl-sn-glycero-3-phosphocholine increased by 1.93-fold than that of WT. The affinity of mutant proteins with phospholipid substrate was significantly changed, indicating that E54 plays an important role in the substrate head-group selectivity of hGIIE.

Development and evaluation of a novel method for rapid screening of Pichia pastoris strains capable of efficiently expressing recombinant proteins / 生物工程学报

Pichia pastoris is one of the most widely used recombinant protein expression systems. In this study, a novel method for rapid screening of P. pastoris strains capable of efficiently expressing recombinant proteins was developed. Firstly, the ability to express recombinant proteins of the modified strain GS115-E in which a functional Sec63-EGFP (Enhanced green fluorescent protein) fusion protein replaced the endogenous endoplasmic reticulum transmembrane protein Sec63 was tested. Next, the plasmids carrying different copy numbers of phytase (phy) gene or xylanase (xyn) gene were transformed into GS115-E to obtain recombinant strains with different expression levels of phytase or xylanase, and the expression levels of EGFP and recombinant proteins in different strains were tested. Finally, a flow cytometer sorter was used to separate a mixture of cells with different phytase expression levels into sub-populations according to green fluorescence intensity. A good linear correlation was found between the fluorescence intensities of EGFP and the expression levels of the recombinant proteins in the recombinant strains (0.8<|R|<1). By using the flow cytometer, high-yielding P. pastoris cells were efficiently screened from a mixture of cells. The expression level of phytase of the selected high-fluorescence strains was 4.09 times higher than that of the low-fluorescence strains after 120 h of methanol induction. By detecting the EGFP fluorescence intensity instead of detecting the expression level and activity of the recombinant proteins in the recombinant strains, the method developed by the present study possesses the greatly improved performance of convenience and versatility in screening high-yielding P. pastoris strains. Combining the method with high-throughput screening instruments and technologies, such as flow cytometer and droplet microfluidics, the speed and throughput of this method will be further increased. This method will provide a simple and rapid approach for screening and obtaining P. pastoris with high abilities to express recombinant proteins.

Discovery and functional verification of endogenous glucanases for scleroglucan hydrolysis in Sclerotium rolfsii / 生物工程学报

Scleroglucan is a high-molecular water-soluble microbial exopolysaccharide and mainly applied in the fields of petroleum, food, medicine and cosmetics. The high molecular weight of scleroglucan produced by microbial fermentation leads to low solubility, high viscosity and poor dispersibility, thus bringing a series of difficulties to extraction, preservation and application. It is important to explore suitable degradation method to adjust the molecular weight of scleroglucan for expanding its industrial application. Taking Sclerotium rolfsii WSH-G01 as a model strain, in which functional annotations of the glucanase genes were conducted by whole genome sequencing. Based on design of culture system for culture system for differential expression of β-glucanase, endogenous β-glucanase genes in S. rolfsii WSH-G01 were excavated by transcriptomics analysis. Functions of these potential hydrolases were further verified. Finally, 14 potential endogenous hydrolase genes were obtained from S. rolfsii. After heterologous overexpression in Pichia pastoris, 10 soluble enzymes were obtained and 5 of them had the activity of laminarin hydrolysis by SDS-PAGE and enzyme activity analysis. Further investigation of the 5 endogenous hydrolases on scleroglucan degradation showed that enzyme GME9860 has positive hydrolysis effect. The obtained results provide references not only for obtaining low and medium molecular weight of scleroglucan with enzymatic hydrolysis, but also for producing different molecular weight of scleroglucan during S. rolfsii fermentation process with metabolic engineering.

Absceso cerebral por Cladophialophora bantiana en un paciente con trasplante renal: reporte de un caso / Brain abscess caused by Cladophialophora bantiana after renal allograft loss: A case report

Resumen Las feohifomicosis cerebrales son infecciones graves causadas por mohos dematiáceos, entre los cuales Cladophialophora bantiana es una de las especies más comúnmente aislada. Esta tiene tropismo por el sistema nervioso central y frecuentemente produce abscesos cerebrales en pacientes inmunocompetentes; además, en los inmunocomprometidos también puede ocasionar infección diseminada. Pese a la disponibilidad de medicamentos antifúngicos de amplio espectro, a menudo se requiere también la intervención quirúrgica; de todas maneras, la mortalidad es elevada. El diagnóstico debe hacerse interviniendo para tomar la muestra y hacer el cultivo y las pruebas de sensibilidad. Se presenta aquí el caso de un paciente con trasplante renal que presentó un absceso cerebral por C. bantiana, el cual se extrajo mediante resección quirúrgica. El paciente recibió tratamiento con voriconazol, con adecuada respuesta, mejoría y sin secuelas neurológicas.

Abstract Cerebral feohifomycosis are severe infections caused by dematiaceous fungi. Cladophialophora bantiana is one of the most commonly isolated species; it has central nervous system tropism and it often manifests as a brain abscess in immunocompetent patients. In immunocompromised patients, it can lead to brain abscesses and disseminated infections. Despite the availability of broad-spectrum antifungal drugs, it is a must to perform surgical management, in addition to drug therapy. However, mortality is high. The diagnostic approach must be invasive to establish a timely diagnosis and direct treatment based on culture and susceptibility tests. We report a case of brain abscess caused by C. bantiana in an immunosuppressed patient who was treated with surgical resection and voriconazole with an adequate response to therapy and without neurological sequels.

Mutation Analysis of Synthetic DNA Barcodes in a Fission Yeast Gene Deletion Library by Sanger Sequencing

Incorporation of unique barcodes into fission yeast gene deletion collections has enabled the identification of gene functions by growth fitness analysis. For fine tuning, it is important to examine barcode sequences, because mutations arise during strain construction. Out of 8,708 barcodes (4,354 strains) covering 88.5% of all 4,919 open reading frames, 7,734 barcodes (88.8%) were validated as high-fidelity to be inserted at the correct positions by Sanger sequencing. Sequence examination of the 7,734 high-fidelity barcodes revealed that 1,039 barcodes (13.4%) deviated from the original design. In total, 1,284 mutations (mutation rate of 16.6%) exist within the 1,039 mutated barcodes, which is comparable to budding yeast (18%). When the type of mutation was considered, substitutions accounted for 845 mutations (10.9%), deletions accounted for 319 mutations (4.1%), and insertions accounted for 121 mutations (1.6%). Peculiarly, the frequency of substitutions (67.6%) was unexpectedly higher than in budding yeast (~28%) and well above the predicted error of Sanger sequencing (~2%), which might have arisen during the solid-phase oligonucleotide synthesis and PCR amplification of the barcodes during strain construction. When the mutation rate was analyzed by position within 20-mer barcodes using the 1,284 mutations from the 7,734 sequenced barcodes, there was no significant difference between up-tags and down-tags at a given position. The mutation frequency at a given position was similar at most positions, ranging from 0.4% (32/7,734) to 1.1% (82/7,734), except at position 1, which was highest (3.1%), as in budding yeast. Together, well-defined barcode sequences, combined with the next-generation sequencing platform, promise to make the fission yeast gene deletion library a powerful tool for understanding gene function.

Successful treatment of fungal endophthalmitis using intravitreal caspofungin / O primeiro relato de caspofungina intravítrea no tratamento de endoftalmite fúngica

ABSTRACT Fungal endophthalmitis is a rare condition often associated with poor prognosis. We present a case of postoperative acute fungal endophthalmitis caused by the yeast-like fungus Stephanoascus ciferrii (Candida ciferrii). The fungus was resistant to fluconazole, voriconazole, and amphotericin B but susceptible to caspofungin. Because the degree of vitreal penetration of caspofungin after its intravenous administration is unclear, we performed multiple intravitreal injections, first with 50 µg/0.1 ml and then with 250 µg/0.1 ml caspofungin. Despite the recurrence of symptoms, intravitreal injection of caspofungin finally abolished the inflammation and achieved ambulatory vision that persisted until 1 year of follow-up. To our knowledge, this is the first report of S. ciferrii endophthalmitis and its successful treatment with intravitreal caspofungin.

RESUMO Endoftalmite fúngica é uma ocorrência rara, muitas vezes associada com mau prog nóstico. Apresentamos um caso de endoftalmite fúngica aguda pós-operatória causada por fungo de levedura incomum, Stephanoascus ciferrii (Candida ciferrii). O fungo foi resistente ao fluconazol, ao voriconazol e à anfotericina B e susceptível à caspofun gina. Dado que a penetração vítrea da caspofungina após administração intravenosa não é clara, optou-se por realizar múltiplas injecções intravítreas, primeiro de 50 µg e depois de 250 µg de caspofungina, e finalmente obteve-se a resolução da inflamação e a visão recuperada foi mantida por pelo menos um ano após o ocorrido. No nosso conhecimento, este é o primeiro relato de endoftalmite por Stephanoascus ciferrii e o primeiro relato de endoftalmite fúngica tratada com sucesso com caspofungina intravítrea.

Cryptococcus Species Infection in a Bone Marrow Transplant Patient and Review of the Literature / 대한의진균학회지

Cryptococcosis is caused by several Cryptococcus species, including C. neoformans and C. gattii. Skin involvement is seen in 10~20% of systemic cryptococcosis. There are also rare cases of primary cutaneous cryptococcosis in which skin-penetrating trauma is the alleged mechanism of infection. A 16-year-old male presented with multiple, 0.2~0.3 cm-sized, brownish papules on the whole body for 2 weeks. He had past history of acute lymphoblastic leukemia and received bone marrow transplant 1 year ago. After leukemia had recurred 1 month ago and after chemotherapy, multiple brownish papules developed. Histopathologic examinations revealed narrow-based budding yeasts in hematoxylin and eosin, Periodic acid-Schiff, and Gomori methenamine silver stains. Also in mucicarmine stain there were pink-colored capsules around the cell walls. Finally it was diagnosed as deep fungal infection due to Cryptococcus species. In spite of administrating fluconazole, the patient expired due to respiratory failure caused by pneumonia. Herein, we report a case of Cryptococcus species infection in a bone marrow transplant patient.

Infección por Kodamaea ohmeri en un recién nacido con una masa mediastinal / Kodamaea ohmeri infection in a newborn with a mediastinal mass

Las infecciones por hongos son una causa de morbilidad y mortalidad, lo que lleva a un incremento de la estancia hospitalaria y a un aumento de los costos en salud, en el período neonatal. Durante este período, los prematuros son los más afectados. Las especies Candida son la causa principal de infección fúngica. La mayoría son causadas por C. albicans, C. parapsilosis, C. glabrata y C. tropicalis, aunque otras especies han sido reportadas. Una de ellas, como un patógeno emergente, es K. ohmeri. Este organismo ha sido reportado como patógeno en el período neonatal, principalmente en prematuros. Los factores de riesgo asociados a infección fúngica son accesos venosos centrales, inmunosupresión, larga estancia hospitalaria, intubación endotraqueal y uso de antibióticos. Presentamos a un neonato con una masa mediastinal, quien requirió múltiples intervenciones, como pericardiocentesis, catéter central, ventilación mecánica y antibióticos. Durante su evolución, presentó infección por K. ohmeri. Fue tratado con anfotericina B, con evolución clínica satisfactoria.

Invasive fungal infections are a considerable cause of morbidity, mortality, increased hospital stay durations, and high health care costs, during neonatal period. In this period, the premature infants are the most affected. Candida species are the leading cause of invasive fungal infections. The majority of neonatal Candida infections are caused by C. albicans, C. parapsilosis, C. glabrata and C. tropicalis, although other fungus species are being reported. One such emerging pathogen is K. ohmeri. This organism has been reported as a pathogen in the neonatal period, principally in premature infants. The risk factors associated with fungal infection are central line, immunosuppression, prolonged hospital stay, endotracheal intubation and exposure to antibiotics. We present a term baby with a mediastinal mass, who required several procedures, as pericardiocentesis, central catheters, mechanical ventilation, antibiotics. During his evolution, he presented infection by K. ohmeri. The baby was treated with amphotericin B, with satisfactory clinical course.

Budding Yeast Cells in Peripheral Blood Smear: Clue to Candidemia

No abstract available.

Invasive infection due to Saprochaete capitata in a young patient with hematological malignancies

We report a case of invasive infection due to Saprochaete capitata in a patient with hematological malignancies after chemotherapy treatment and empiric antifungal therapy with caspofungin. Although severely immunocompromised the patient survived been treated with amphotericin B lipid complex associated with voriconazole.

Depletion of epsilon-COP in the COPI Vesicular Coat Reduces Cleistothecium Production in Aspergillus nidulans

We have previously isolated epsilon-COP, the alpha-COP interactor in COPI of Aspergillus nidulans, by yeast two-hybrid screening. To understand the function of epsilon-COP, the aneA+ gene for epsilon-COP/AneA was deleted by homologous recombination using a gene-specific disruption cassette. Deletion of the epsilon-COP gene showed no detectable changes in vegetative growth or asexual development, but resulted in decrease in the production of the fruiting body, cleistothecium, under conditions favorable for sexual development. Unlike in the budding yeast Saccharomyces cerevisiae, in A. nidulans, over-expression of epsilon-COP did not rescue the thermo-sensitive growth defect of the alpha-COP mutant at 42degrees C. Together, these data show that epsilon-COP is not essential for viability, but it plays a role in fruiting body formation in A. nidulans.

First isolation of the Stephanoascus ciferrii in feline otitis in Brazil

Ear infections in cats are uncommon, especially involving yeasts. This report describes the first isolation of the Stephanoascus ciferrii, teleomorph of the Candida genus, in a case of feline otitis in Brazil. The identification and characterization of Stephanoascus ciferrii were confirmed by the Vitek2 System (BioMerieux ®).

Effect of byproducts in lignocellulose hydrolysates on ethanol fermentation by Issatchenkia orientalis / 生物工程学报

Byproducts in lignocellulose hydrolysates, namely sodium formate (1 to 5 g/L), sodium acetic (2.5 to 8.0 g/L), furfural (0.2-2 g/L), 5-hydroxymethylfurfural (5-HMF, 1 to 1.0 g/L) or vanillin (0.5 to 2 g/L) were used to evaluate their effects on ethanol fermentation by Issatchenkia orientalis HN-1 using single factor test and the response surface central composite experiment. Results showed that most of the byproducts had no obvious inhibition on the production of ethanol, except for the addition of 2 g/L vanillin or 1 g/L of 5-HMF, which reduced the ethanol production by 20.38% and 11.2%, respectively. However, high concentration of some byproducts in lignocellulose hydrolysates, such as sodium formate (1 to 5 g/L), sodium acetic (2.5 to 8.0 g/L), furfural (0.2 to 2 g/L) and vanillin (0.5 to 2 g/L) inhibited the growth of I. orientalis HN-1 significantly. Compared with the control, the dry cell weight of I. orientalis HN-1 decreased by 25.04% to 37.02%, 28.83% to 43.82%, 20.06% to 37.60% and 26.39% to 52.64%, respectively, when the above components were added into the fermentation broth and the fermentation lasted for 36 h. No significant interaction effect of the various inhibitors (sodium formate, sodium acetic, furfural and vanillin) except for vanillin single factor on the ethanol production was observed based on the central composite experiments. The concentrations of byproducts in most lignocellulose hydrolysates were below the initial inhibition concentration on ethanol production by Issatchenkia orientalis HN-1, which indicated that Issatchenkia orientalis HN-1 can be used for ethanol production from lignocellulose hydrolysates.

Msi1-Like (MSIL) Proteins in Fungi

Msi1-like (MSIL) proteins, which are eukaryote-specific and contain a series of WD40 repeats, have pleiotropic roles in chromatin assembly, DNA damage repair, and regulation of nutrient/stress-sensing signaling pathways. In the fungal kingdom, the functions of MSIL proteins have been studied most intensively in the budding yeast model Saccharomyces cerevisiae, an ascomycete. Yet their functions are largely unknown in other fungi. Recently, an MSIL protein, Msl1, was discovered and functionally characterized in the pathogenic yeast Cryptococcus neoformans, a basidiomycete. Interestingly, MSIL proteins appear to have redundant and unique roles in both fungi, suggesting that MSIL proteins may have evolutionarily divergent roles in different parts of the fungal kingdom. In this review, we will describe the current findings regarding the role of MSIL proteins in fungi and discuss future directions for research on this topic.

Occurrence of Brettanomyces/Dekkera in Brazilian red wines and its correlation with ethylphenols

The yeast Brettanomyces/Dekkeracan cause important spoilage in wines, with the production of ethylphenols and other off-flavor compounds. This study aimed at determining the presence of this yeast and the ethylphenols produced by them in Brazilian red wines, establishing their relationship with other chemical characteristics. Isolates of Brettanomyces/Dekkerawere quantified by plating 126 samples of dry red wine in selective culture medium, while ethylphenols were analyzed by solid phase extraction and GC/FID. Free and total SO2, alcohol, total dry extract, residual sugar, total and volatile acidity, and pH were also determined. Brettanomyces/Dekkerawas present in 27% of samples. Ethylphenols were detected in most samples, with amounts higher than the threshold limit of 426 mg/L found in 46.03% of samples. The majority of wine samples showed inadequate levels of SO2and residual sugars, facts that might facilitate microbial spoilage. The passage in barrels and the grape varieties (Cabernet Sauvignon and Merlot), did not show any influence on the levels of contamination or ethylphenols contents. The prevalence of Brettanomyces/Dekkeraand the concentrations of ethylphenols were high considering the sensory impact they can cause. The growth of Brettanomyces/Dekkerawas dependent on the levels of SO2and alcohol of wines. Knowledge of the contamination, the presence of ethylphenols, and their relationship with the chemical characteristics of wines can entice effective measures to prevent Brettanomyces/Dekkeraand contribute to improve the general quality of Brazilian red wines.

Primary Cutaneous Cryptococcosis Mimicking Herpes Zoster / 대한피부과학회지

Primary cutaneous cryptococcosis (PCC) is a localized skin infection confined to one body region, without evidence of dissemination. The clinical presentation of PCC is so variable that its diagnosis requires a high index of suspicion. A 52-year-old woman presented with localized grouped erythematous papulovesicles on the left ear lobe for 6 months with wax and wane pattern. However, there were no signs of systemic cryptococcal infection. Histopathological examination showed numerous encapsulated round spores and budding yeasts in the dermis. Culture of aspirate from the wound and tissue samples revealed Cryptococcus neoformans. Herein, we report an interesting case of PCC on the left ear that clinically mimics herpes zoster.

Research progress on spindle assembly checkpoint gene BubR1 / 浙江大学学报·医学版

BubR1 gene is a homologue of the mitotic checkpoint gene Mad3 in budding yeast which is highly conserved in mammalian. BubR1 protein is a key component mediating spindle assembly checkpoint activation. BubR1 safeguards accurate chromosome segregation during cell division by monitoring kinetochore-microtubule attachments and kinetochore tension. There is a dose-dependent effect between the level of BubR1 expression and the function of spindle assembly checkpoint. BubR1-deficient would lead to mitotic progression with compromised spindle assembly checkpoint because cells become progressively aneuploid. Recently, it has been reported that BubR1 also plays important roles in meiotic, DNA damage response, cancer, infertility, and early aging. This review briefly summarizes the current progresses in studies of BubR1 function.

Subcutaneous Candidal Abscess in the Patient with Iatrogenic Cushing Syndrome / 대한의진균학회지

Candida albicans is a dimorphic yeast which is responsible for 70 percent to 80 percent of all candidial infection, and is the most common cause of superficial and systemic candidiasis. Invasive candidiasis occurs under certain circumstances such as immunosuppression, prolonged hospitalization, and previous antibiotics use. We report a case of candidiasis with a unusual presentation of subcutaneous abscess. A 54 year-old woman came to our clinic with painful erythematous swelling plaques and nodules on the face and arms. She was hospitalized with generalized edema and weakness of both leg. She had a history of herbal medication for 1 year and was finally diagnosed with iatrogenic Cushing syndrome in department of the endocrinology. Biopsy of the lesion revealed chronic inflammation in dermis and subcutis and budding yeasts with pseudohyphae were shown in Gomoris Methenamine silver stain. And Candida albicans was identified by fungus culture.