Single-cell analysis of white adipose tissue reveals the tumor-promoting adipocyte subtypes.

BACKGROUND: The tumor-adipose microenvironment (TAME) is characterized by the enrichment of adipocytes, and is considered a special ecosystem that supports cancer progression. However, the heterogeneity and diversity of adipocytes in TAME remains poorly understood. METHODS: We conducted a single-cell RNA sequencing analysis of adipocytes in mouse and human white adipose tissue (WAT). We analyzed several adipocyte subtypes to evaluate their relationship and potential as prognostic factors for overall survival (OS). The potential drugs are screened by using bioinformatics methods. The tumor-promoting effects of a typical adipocyte subtype in breast cancer are validated by performing in vitro functional assays and immunohistochemistry (IHC) in clinical samples. RESULTS: We profiled a comprehensive single-cell atlas of adipocyte in mouse and human WAT and described their characteristics, origins, development, functions and interactions with immune cells. Several cancer-associated adipocyte subtypes, namely DPP4+ adipocytes in visceral adipose and ADIPOQ+ adipocytes in subcutaneous adipose, are identified. We found that high levels of these subtypes are associated with unfavorable outcomes in four typical adipose-associated cancers. Some potential drugs including Trametinib, Selumetinib and Ulixertinib are discovered. Emphatically, knockdown of adiponectin receptor 1 (AdipoR1) and AdipoR2 impaired the proliferation and invasion of breast cancer cells. Patients with AdipoR2-high breast cancer display significantly shorter relapse-free survival (RFS) than those with AdipoR2-low breast cancer. CONCLUSION: Our results provide a novel understanding of TAME at the single-cell level. Based on our findings, several adipocyte subtypes have negative impact on prognosis. These cancer-associated adipocytes may serve as key prognostic predictor and potential targets for treatment in the future.

Human cytomegalovirus infection perturbs neural progenitor cell fate via the expression of viral microRNAs.

Human cytomegalovirus (HCMV) preferentially targets neural progenitor cells (NPCs) in congenitally infected fetal brains, inducing neurodevelopmental disorders. While HCMV expresses several microRNAs (miRNAs) during infection, their roles in NPC infection are unclear. Here, we characterized expression of cellular and viral miRNAs in HCMV-infected NPCs during early infection by microarray and identified seven differentially expressed cellular miRNAs and six significantly upregulated HCMV miRNAs. Deep learning approaches were used to identify potential targets of significantly upregulated HCMV miRNAs against differentially expressed cellular messenger RNA (mRNAs), and the associations with miRNA-mRNA expression changes were observed. Gene ontology enrichment analysis indicated cellular gene targets were significantly enriched in pathways involved in neurodevelopment and cell-cycle processes. Viral modulation of selected miRNAs and cellular gene targets involved in neurodevelopmental processes were further validated by real-time quantitative reverse transcription polymerase chain reaction. Finally, a predicted 3' untranslated region target site of hcmv-miR-US25-1 in Jag1, a factor important for neurogenesis, was confirmed by mutagenesis. Reduction of Jag1 RNA and protein levels in NPCs was observed in response to transient expression of hcmv-miR-US25-1. A hcmv-miR-US25-1 mutant virus (ΔmiR-US25) displayed limited ability to downregulate Jag1 mRNA levels and protein levels during the early infection stage compared with the wild type virus. Our collective experimental and computational investigation of miRNAs and cellular mRNAs expression in HCMV-infected NPCs yields new insights into the roles of viral miRNAs in regulating NPC fate and their contributions to HCMV neuropathogenesis.

First report of Fusarium falciforme causing root rot of pomegranate (Punica granatum L.) in China.

Pomegranate (Punica granatum L.) is a deciduous shrub or small tree that is native to Iran and Afghanistan. It is also a commercially important fruit tree in China and worldwide. In the summer of 2022, a serious root rot disease occurred in some pomegranate orchards in Xichuan County(32º42´ N, 111º48´ E), Henan Province, China, with an incidence of ~30%. Symptoms included leaf yellowing and wilting, root browning and rotting, and stem-base cracking, eventually leading to defoliation and death. To isolate the causal agent, small pieces (5×5 mm) of diseased root from six trees were surface-sterilized by dipping in 2% NaClO for 8 min followed by 70% ethanol for 15 s, rinsed five times with sterile water, and plated on potato dextrose agar (PDA), then incubated at 28°C in the dark for 5 days. Fifteen pure fungal isolates with the same morphological characteristics were obtained from 24 pieces of roots. All isolates produced white fluffy mycelia. Microconidia were hyaline, oval or reniform, with zero to one septa and dimensions of 7.1 to 19.9 (average 14.5 )× 3.8 to 8.0 (average 5.6) µm (n = 100). Macroconidia were sickle-shaped, one to four septate, and 20.1 to 40.8 (average 26.5) × 4.8 to 8.6 (average 6.5) µm (n = 100). Chlamydospores were spherical, single, in pairs or chains, and 5.6 to 9.8 (average 6.8) µm in diameter (n = 100). Based on the above characteristics, the pathogens were identified as Fusarium sp. (Leslie and Summerell 2006). Genomic DNA was extracted from mycelia of two representative isolates Fs1 and Fs3. The internal transcribed spacer (ITS), translation elongation factor 1-alpha (TEF-1α) and RNA polymerase II second largest subunit (RPB2) sequences were PCR amplified using primer pairs of ITS1/ITS4, EF1/EF2, and RPB2-5f2/RPB2-7cr, RPB2-7cf/RPB2-11ar (O'Donnell et al., 2022), respectively. BLAST analysis showed that the ITS, TEF-1α and RPB2 sequences of isolates Fs1(GenBank accession nos. OK001765, OQ921726 and OQ928396) and Fs3 (GenBank accession nos. OK001771, OQ921727 and OQ928397) showed 99%-100% identity with multiple GenBank sequences of Fusarium falciforme (KY617066, MN064683, KF255514, OQ933361, KY556711 and ON331935). A phylogenetic tree based on concatenated sequences of ITS, TEF-1α and RPB2 using maximum-likelihood analysis revealed that both isolates Fs1 and Fs3 were in the same clade with F. falciforme strains. Based on the morphological and molecular characteristics, the isolates were identified as members of F. falciforme. For pathogenicity testing, conidial suspensions (1×108 spores /mL) of isolates Fs1 and Fs3 were poured onto the roots of healthy pomegranate that had been planted in pots two months previously. Ten plants were inoculated for each isolate. Control plants were drenched with sterile water. After 3 months, inoculated plants developed leaf yellowing and wilting accompanied by root browning and rotting, much like symptoms observed in field plants. The same fungi re-isolated from the experimental plants were confirmed to be F. falciforme by morphology and sequence analysis. This is the first report of F. falciforme causing root rot on pomegranate. F. falciforme is a ubiquitous soil-borne pathogen that causes root rot on multiple plants around the world (Xu F., et al. 2022; Qiu R., et al. 2023). The results of pathogen identification are essential precursors to development of effective control of the disease.

First Report of Leaf Black Spot Caused by Alternaria alternata on Rosemary (Rosmarinus officinalis L.) in China.

Rosemary (Rosmarinus officinalis L.) is an aromatic, evergreen, medicinally important shrub and widely used for cooking, tea, cosmetics as well as medicinal materials. It is grown in many countries including China that had more than 9300 hm2 of commercial cultivation area in 2021. In March 2020, a leaf spot disease sporadic occurred in field rosemarry plants in Nanyang City (32º51´ N, 111º36´ E), Henan Province, China. The disease outbreaked in September with a disease incidence of 57-83%. Symptoms initially appeared as small brown leaf spots that gradually expanded into dark blackbrown irregular lesions. Most of the spots started from the leaf tip or leaf margin, and gradually spread to the leaf base, resulting in heavy defoliation especially on rainy days. Diseased leaf segments (1×3 mm) were surface-sterilized by dipping in 1% sodium hypochlorite for 1 min, rinsed three times with sterile distilled water, and plated on potato dextrose agar, then incubated at 28°C in the dark for 5 days. Twelve fungal isolates with the same morphological characteristics were obtained from nine affected leaves. The fungal colonies were initially white and turned gray brown with flocculent aerial mycelia and a whorled back. Conidia were frequently born in a long chain, with a short beak, brown or light-brown, 13.2 to 48. 7 (average 26.1) × 4.0 to 13.1 (average 8.0) µm in size (n=148) with 0 to 8 transverse and 0 to 3 longitudinal/oblique septa. Phenotypic features of the isolates agreed with those of Alternaria alternata (Simmons et al. 2007). Two isolates Aa1 and Aa2 were randomly selected for molecular and pathogenicity tests. DNA was extracted from mycelia. Partial sequences of internal transcribed spacer (ITS) and translation elongation factor 1-alpha (TEF1-α) were amplified using the primer pairs ITS1/ITS4 and EFI-728F/EFI-986R (Wei et al. 2022), respectively. The GenBank accession nos. were OK036714 and OK036715 for ITS, and ON951980 and ON951981 for TEF1-α of Aa1 and Aa2, respectively, with a maximal identity of greater than 99% to multiple A. alternata strains. In the neighbour joining phylogenetic tree of the amplified ITS and TEF1-α sequences both Aa1 and Aa2 clustered with A. alternata strains, clearly separating them from other Alternaria spp. For pathogenicity test, conidial suspensions (1×106 spores /mL) of Aa1 and Aa2 were separately sprayed on healthy one-year-old rosemary plants (n=3) with their leaves slightly wounded with a sterilized needle. Control plants (n=3) were sprayed with sterile water. Both inoculated and control plants were incubated at 90% RH, 28 °C. After 14 days, all the inoculated leaves showed black brown lesions similar to those on naturally affected field plants, whereas controls remained symptomless. Fungal cultures with the same phenotypic features as the inocula were constantly re-isolated from the infected leaves. A. alternata was reported as pathogen causing foliar necrosis on rosemary in Italy (Perello et al.1995) and leaf spot (or leaf blight) on multiple plant species such as Actaea dahurica (Hai et al. 2022), and Ligustrum japonicum (Wei et al. 2022) in China. This is the first report of A. alternata causing leaf black spot on rosemary in China.

Associations between hepatitis B virus infection and risk of colorectal Cancer: a population-based prospective study.

BACKGROUND: Previous studies have observed a close association between hepatitis B virus (HBV) infection and hepatocellular carcinoma (HCC) as well as extrahepatic cancers. However, research concerning the effect of HBV infection on the risk of colorectal cancer (CRC) is rare and inconsistent. This study aims to determine the relationship between HBV infection and new-onset CRC. METHODS: We prospectively examined the relationship between HBV infection and new-onset CRC among 93,390 participants from Kailuan Cohort study. Cox proportional hazards regression models, subgroup analyses and competing risk analyses were used to evaluate the association between HBV infection and the risk of new-onset CRC. RESULTS: During a median follow-up of 11.28 years, 448 incident CRC cases were identified. The adjusted HR (95%confidence interval (CI)) for the association of HBsAg Seropositive with CRC was 1.85(1.15 ~ 2.96) in the Cox regression. Subgroup analyses showed that the HBsAg seropositive group was associated with increased risk of new-onset CRC among male, middle-aged, normal weight, smokers and non-drinker participants, respectively. A positive association of HBV infection with the risk of CRC was observed in the adjusted sub-distribution proportional hazards (SD) models (HRSD = 1.77, 95% CI:1.11-2.84) and cause-specific hazards (CS) models (HRCS = 1.79, 95% CI: 1.13-2.91). CONCLUSIONS: Our results have found a significant association between HBV infection and the risk of incident CRC among Chinese participants. TRIAL REGISTRATION: Kailuan study, ChiCTR-TNRC-11001489. Registered 24 August 2011 - Retrospectively registered, http:// http://www.chictr.org.cn/showprojen.aspx?proj=8050.

Ethanol tolerance assessment in recombinant E. coli of ethanol responsive genes from Lactobacillus buchneri NRRL B-30929.

We previously identified specific proteins associated with ethanol stress response in a Lactobacillus buchneri strain capable of growing in 10% ethanol. In the current study, the exceptional roles of ethanol responsive genes are examined to determine if they can increase ethanol tolerance in E. coli host cells. The recombinant strains carrying ethanol responsive genes were subjected to growth analyses in media with and without 4% ethanol. Among the expression of these genes and growth analyses of the recombinant strains in ethanol, six genes Lbuc_0522 (NADPH-dependent methylglyoxal reductase), Lbuc_0354 (succinate semialdehyde dehydrogenase), Lbuc_1211(threonyl_tRNA synthetase), Lbuc_2051 (nitroreductase), Lbuc_0707 (branched chain amino acid aminotransferase) and Lbuc_1852 (proline-specific peptidase) conferred host cells tolerance to 4% ethanol. Six genes Lbuc_1523 (phage major capsid protein, HK 97 family), Lbuc_1319 (phosphoglycerate kinase), Lbuc_0787 encoding fumarylacetoacetate hydrolase, Lbuc_1219 encoding UDP-N-acetylmuramate-L-alanine ligase, Lbuc_0466 encoding ornithine carbamoyltransferase and Lbuc_0858 encoding glycine hydroxymethyltransferase showed no impact on growth in media with 4% ethanol with IPTG induction when compared with E. coli carrying control pET28b plasmid. The expression of two genes Lbuc_1557 (S-layer glycoprotein) and Lbuc_2157 (6-phosphogluconate dehydrogenase) resulted ethanol sensitivity phenotype.

Increased ethanol tolerance associated with the pntAB locus of Oenococcus oeni and Lactobacillus buchneri.

Lactobacillus buchneri and Oenococcus oeni are two unique ethanol-tolerant Gram-positive bacteria species. Genome comparison analyses revealed that L. buchneri and O. oeni possess a pntAB locus that was absent in almost all other lactic acid bacteria (LAB) genomes. Our hypothesis is that the pntAB locus contributes to the ethanol tolerance trait of these two distinct ethanol-tolerant organisms. The pntAB locus, consisting of the pntA and pntB genes, codes for NADP(H) transhydrogenase subunits. This membrane-bound transhydrogenase catalyzes the reduction of NADP+ and is known as an important enzyme in maintaining cellular redox balance. In this study, the transhydrogenase operon from L. buchneri NRRL B-30929 and O. oeni PSU-1 were cloned and analyzed. The LbpntB shared 71.0% identity with the O. oeni (OopntB). The entire pntAB locus was expressed in Lactococcus lactis ssp. lactis IL1403 resulting in an increased tolerance to ethanol (6%), butanol (1.8%) and isopropanol (1.8%) when compared to the control strain. However, the recombinant E. coli cells carrying the entire pntAB locus did not show any improved ethanol tolerance. Independent expression of OopntB and LbpntB in recombinant E. coli BL21(DE3)pLysS host demonstrated higher tolerance to ethanol when compared with a control E. coli BL21(DE3)pLysS strain carrying pET28b vector. Ethanol tolerance comparison of E. coli strains carrying LbpntB and OopntB showed that LbpntB conferred higher ethanol tolerance (4.5%) and resulted in greater biomass, while the OopntB conferred lower ethanol tolerance (4.0%) resulted lower biomass. Therefore, the pntB gene from L. buchneri is a better choice in generating higher ethanol tolerance. This is the first study to uncover the role of pntAB locus on ethanol tolerance.

West Nile Virus NS1 Antagonizes Interferon Beta Production by Targeting RIG-I and MDA5.

West Nile virus (WNV) is a mosquito-borne flavivirus that causes epidemics of encephalitis and viscerotropic disease worldwide. This virus has spread rapidly and has posed a significant public health threat since the outbreak in New York City in 1999. The interferon (IFN)-mediated antiviral response represents an important component of virus-host interactions and plays an essential role in regulating viral replication. Previous studies have suggested that multifunctional nonstructural proteins encoded by flaviviruses antagonize the host IFN response via various means in order to establish efficient viral replication. In this study, we demonstrated that the nonstructural protein 1 (NS1) of WNV antagonizes IFN-ß production, most likely through suppression of retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) activation. In a dual-luciferase reporter assay, WNV NS1 significantly inhibited the activation of the IFN-ß promoter after Sendai virus infection or poly(I·C) treatment. NS1 also suppressed the activation of the IFN-ß promoter when it was stimulated by interferon regulatory factor 3 (IRF3)/5D or its upstream molecules in the RLR signaling pathway. Furthermore, NS1 blocked the phosphorylation and nuclear translocation of IRF3 upon stimulation by various inducers. Mechanistically, WNV NS1 targets RIG-I and melanoma differentiation-associated gene 5 (MDA5) by interacting with them and subsequently causing their degradation by the proteasome. Furthermore, WNV NS1 inhibits the K63-linked polyubiquitination of RIG-I, thereby inhibiting the activation of downstream sensors in the RLR signaling pathway. Taken together, our results reveal a novel mechanism by which WNV NS1 interferes with the host antiviral response.IMPORTANCE WNV Nile virus (WNV) has received increased attention since its introduction to the United States. However, the pathogenesis of this virus is poorly understood. This study demonstrated that the nonstructural protein 1 (NS1) of WNV antagonizes the induction of interferon beta (IFN-ß) by interacting with and degrading retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5), which are crucial viral sensors in the host innate immune system. Further experiments suggested that NS1-mediated inhibition of the RIG-I-like receptor (RLR) signaling pathway involves inhibition of RIG-I K63-linked polyubiquitination and that the proteasome plays a role in RIG-I degradation. This study provides new insights into the regulation of WNV NS1 in the RLR signaling pathway and reveals a novel mechanism by which WNV evades the host innate immune response. The novel findings may guide us to discover new therapeutic targets and develop effective vaccines for WNV infections.

Development and evaluation of one-step multiplex real-time RT-PCR assay for simultaneous detection of Zika virus and Chikungunya virus.

Zika virus (ZIKV) and chikungunya virus (CHIKV) are important human pathogens and mosquito-borne arboviruses, which have resembling history, common vectors, circulating regions, and indistinguishable clinical symptoms. Wide geographical range that is suitable for ZIKV and CHIKV transmission underlines the concern about the impact of epidemic and endemic infections on burden of public health. In the present study, a highly sensitive and specific one-step multiplex real-time RT-PCR assay was developed and evaluated for simultaneous detection and quantification of ZIKV and CHIKV. The single reaction assay employs two pairs of primers and two TaqMan probes that differentiate ZIKV and CHIKV infections. The entire viral genomic RNA in vitro transcribed from full-length infectious clones were used to generate the standard curves for absolute quantification in subsequent tests. The detection limit of the one-step multiplex assay was 1 and 0.5 PFU for infectious ZIKV and CHIKV, respectively. The assessment of specificity indicated this assay is highly specific to targeted viruses showing no amplification of a variety of other flaviviruses. Our assay was able to detect geographically separated and phylogenetically diverse strains of ZIKV and CHIKV. On the applicability of monitoring viral multiplication in cells and testing clinical samples, the one-step multiplex assay provided efficient and accurate determination. The one-step multiplex real-time RT-PCR assay offers a valuable tool for detection of ZIKV and CHIKV and potentially contributes to general surveillance and clinical treatment.

Discovery of an acidic, thermostable and highly NADP+ dependent formate dehydrogenase from Lactobacillus buchneri NRRL B-30929.

OBJECTIVES: To identify a robust NADP+ dependent formate dehydrogenase from Lactobacillus buchneri NRRL B-30929 (LbFDH) with unique biochemical properties. RESULTS: A new NADP+ dependent formate dehydrogenase gene (fdh) was cloned from genomic DNA of L. buchneri NRRL B-30929. The recombinant construct was expressed in Escherichia coli BL21(DE3) with 6 × histidine at the C-terminus and the purified protein obtained as a single band of approx. 44 kDa on SDS-PAGE and 90 kDa on native-PAGE. The LbFDH was highly active at acidic conditions (pH 4.8-6.2). Its optimum temperature was 60 °C and 50 °C with NADP+ and NAD+, respectively and its Tm value was 78 °C. Its activity did not decrease after incubation in a solution containing 20% of DMSO and acetonitrile for 6 h. The KM constants were 49.8, 0.12 and 1.68 mM for formate (with NADP+), NADP+ and NAD+, respectively. CONCLUSIONS: An NADP+ dependent FDH from L. buchneri NRRL B-30929 was cloned, expressed and identified with its unusual characteristics. The LbFDH can be a promising candidate for NADPH regeneration through biocatalysis requiring acidic conditions and high temperatures.

Recovery of the Zika virus through an in vitro ligation approach.

In this study, an in vitro ligation method was developed to assemble a full-length infectious cDNA clone of the Zika virus (ZIKV). Four contiguous cDNA subclones covering the complete ZIKV genome were constructed with unique BglI restriction sites at the ends of each fragment. The BglI restriction sites only allow in vitro ligation to happen between interconnecting restriction sites from adjacent cDNA fragments, resulting in an intact full-length cDNA of ZIKV. RNA transcripts derived from the full-length cDNA were infectious. The recombinant virus replicated as efficiently as the wild-type virus with similar growth kinetics and plaque morphologies in Vero and C6/36 cells. Both viruses were inhibited by NITD008 treatment. This in vitro ligation method will facilitate manipulation of the viral genome through genetic modifications of four separated subclones of ZIKV for the rapid and rational development of candidate vaccines and viral replication study.

Development of a stable Japanese encephalitis virus replicon cell line for antiviral screening.

Japanese encephalitis virus (JEV), an important pathogen in Eastern and Southern Asia and the Pacific, has spread to Australia and other territories in recent years. Although the vaccine for JEV has been used in some countries, development of efficient antiviral drugs is still an urgent requirement. Replicon systems have been widely used in the research of viral replication and antiviral screening for West Nile virus (WNV), yellow fever virus (YFV) and dengue virus (DENV). Here, a novel JEV replicon harboring the Rluc and Pac gene (JEV-Pac-Rluc-Rep) was constructed. Furthermore, we established a BHK-21 cell line harboring JEV-Pac-Rluc-Rep (BHK-21/PAC/Rluc cell line) through continuous puromycin selection. Characterization of cell line stability showed that the replicon RNA could persistently replicate in this cell line for at least up to 10 rounds of passage. Using a known flavivirus inhibitor, the JEV replicon cell line was validated for antiviral screening. The JEV replicon cell line will be a valuable tool for both compound screening and viral replication studies.

Progress and perspectives on improving butanol tolerance.

Fermentative production of butanol for use as a biofuel or chemical feedstock is regarded as a promising renewable technology that reduces greenhouse gas emissions and has the potential to become a substitute for non-sustainable chemical production route. However, butanol toxicity to the producing microbes remains a barrier to achieving sufficiently high titers for cost-effective butanol fermentation and recovery. Investigations of the external stress of high butanol concentration on butanol-producing microbial strains will aid in developing improved microbes with increased tolerance to butanol. With currently available molecular tool boxes, researchers have aimed to address and understand how butanol affects different microbes. This review will cover the individual organism's inherent responses to surrounding butanol levels, and the collective efforts by researchers to improve production and tolerance. The specific microorganisms discussed here include the native butanol producer Clostridium species, the fermentation industrial model Saccharomyces cerevisiae and the photosynthetic cyanobacteria, the genetic engineering workhorse Escherichia coli, and also the butanol-tolerant lactic acid bacteria that utilize diverse substrates. The discussion will help to understand the physiology of butanol resistance and to identify specific butanol tolerance genes that will lead to informed genetic engineering strategies for new strain development.

Novel Feruloyl Esterase from Lactobacillus fermentum NRRL B-1932 and Analysis of the Recombinant Enzyme Produced in Escherichia coli.

UNLABELLED: A total of 33 Lactobacillus strains were screened for feruloyl esterase (FE) activity using agar plates containing ethyl ferulate as the sole carbon source, and Lactobacillus fermentum NRRL B-1932 demonstrated the strongest FE activity among a dozen species showing a clearing zone on the opaque plate containing ethyl ferulate. FE activities were monitored using high-performance liquid chromatography with an acetonitrile-trifluoroacetic acid gradient. To produce sufficient purified FE from L. fermentum strain NRRL B-1932 (LfFE), the cDNA encoding LfFE (Lffae) was amplified and cloned by using available closely related genome sequences and overexpressed in Escherichia coli A 29.6-kDa LfFE protein was detected from the protein extract of E. coli BL21(pLysS) carrying pET28bLffae upon IPTG (isopropyl-ß-d-thiogalactopyranoside) induction. The recombinant LfFE containing a polyhistidine tag was purified by nickel-nitrilotriacetic acid affinity resin. The purified LfFE showed strong activities against several artificial substrates, including p-nitrophenyl acetate and 4-methylumbelliferyl p-trimethylammoniocinnamate chloride. The optimum pH and temperature of the recombinant LfFE were around 6.5 and 37°C, respectively, as determined using either crude or purified recombinant LfFE. This study will be essential for the production of the LfFE in E. coli on a larger scale that could not be readily achieved by L. fermentum fermentation. IMPORTANCE: The production of feruloyl esterase (FE) from Lactobacillus fermentum NRRL B-1932 reported in this study will have immense potential commercial applications not only in biofuel production but also in pharmaceutical, polymer, oleo chemical, cosmetic additive, and detergent industries, as well as human health-related applications, including food flavoring, functional foods, probiotic agents, preventive medicine, and animal feed. Given the essential role FE plays in the production of hydroxycinnamic acids and ferulic acid, plus the generally regarded as safe status of lactobacilli, which therefore have less regulatory concerns, LfFE from the probiotic L. fermentum reported in this work can be directly used for increased production of high-value hydroxycinnamates and ferulic acid from natural or synthetic carbon sources.

Phylogenetic classification of Aureobasidium pullulans strains for production of feruloyl esterase.

OBJECTIVE: The objective was to phylogenetically classify diverse strains of Aureobasidium pullulans and determine their production of feruloyl esterase. RESULTS: Seventeen strains from the A. pullulans literature were phylogenetically classified. Phenotypic traits of color variation and endo-ß-1,4-xylanase overproduction were associated with phylogenetic clade 10 and particularly clade 8. Literature strains used for pullulan production all belonged to clade 7. These strains and 36 previously classified strains were tested for feruloyl esterase production, which was found to be associated with phylogenetic clades 4, 11, and particularly clade 8. Clade 8 strains NRRL 58552 and NRRL 62041 produced the highest levels of feruloyl esterase among strains tested. CONCLUSIONS: Production of both xylanase and feruloyl esterase are associated with A. pullulans strains in phylogenetic clade 8, which is thus a promising source of enzymes with potential biotechnological applications.

The yajC gene from Lactobacillus buchneri and Escherichia coli and its role in ethanol tolerance.

The yajC gene (Lbuc_0921) from Lactobacillus buchneri NRRL B-30929 was identified from previous proteomics analyses in response to ethanol treatment. The YajC protein expression was increased by 15-fold in response to 10 % ethanol vs 0 % ethanol. The yajC gene encodes the smaller subunit of the preprotein translocase complex, which interacts with membrane protein SecD and SecF to coordinate protein transport and secretion across cytoplasmic membrane in Escherichia coli. The YajC protein was linked to sensitivity to growth temperatures in E. coli, involved in translocation of virulence factors during Listeria infection, and stimulating a T cell-mediated response of Brucella abortus. In this study, the L. buchneri yajC gene was over-expressed in E. coli. The strain carrying pET28byajC that produces YajC after isopropyl ß-D-1-thiogalactopyranoside induction showed tolerance to 4 % ethanol in growth media, compared to the control carrying pET28b. This is the first report linking YajC to ethanol stress and tolerance.

Growth, ethanol production, and inulinase activity on various inulin substrates by mutant Kluyveromyces marxianus strains NRRL Y-50798 and NRRL Y-50799.

Economically important plants contain large amounts of inulin. Disposal of waste resulting from their processing presents environmental issues. Finding microorganisms capable of converting inulin waste to biofuel and valuable co-products at the processing site would have significant economic and environmental impact. We evaluated the ability of two mutant strains of Kluyveromyces marxianus (Km7 and Km8) to utilize inulin for ethanol production. In glucose medium, both strains consumed all glucose and produced 0.40 g ethanol/g glucose at 24 h. In inulin medium, Km7 exhibited maximum colony forming units (CFU)/mL and produced 0.35 g ethanol/g inulin at 24 h, while Km8 showed maximum CFU/mL and produced 0.02 g ethanol/g inulin at 96 h. At 24 h in inulin + glucose medium, Km7 produced 0.40 g ethanol/g (inulin + glucose) and Km8 produced 0.20 g ethanol/g (inulin + glucose) with maximum CFU/mL for Km8 at 72 h, 40 % of that for Km7 at 36 h. Extracellular inulinase activity at 6 h for both Km7 and Km8 was 3.7 International Units (IU)/mL.

Genetic interaction between NS4A and NS4B for replication of Japanese encephalitis virus.

Flavivirus NS4A and NS4B are important membrane proteins for viral replication that are assumed to serve as the scaffold for the formation of replication complexes. We previously demonstrated that a single Lys-to-Arg mutation at position 79 in NS4A (NS4A-K79R) significantly impaired Japanese encephalitis virus (JEV) replication. In this study, the mutant virus was subject to genetic selection to search for the potential interaction between NS4A and other viral components. Sequencing of the recovered viruses revealed that, in addition to an A97E change in NS4A itself, a Y3N compensatory mutation located in NS4B had emerged from independent selections. Mutagenesis analysis, using a genome-length RNA and a replicon of JEV, demonstrated that both adaptive mutations greatly restored the replication defect caused by NS4A-K79R. Our results, for the first time to our knowledge, clearly showed the genetic interaction between NS4A and NS4B, although the mechanism underlying their interaction is unknown.

Inhibition of enterovirus 71 by adenosine analog NITD008.

Enterovirus 71 (EV71) is a major viral pathogen in China and Southeast Asia. There is no clinically approved vaccine or antiviral therapy for EV71 infection. NITD008, an adenosine analog, is an inhibitor of flavivirus that blocks viral RNA synthesis. Here we report that NITD008 has potent antiviral activity against EV71. In cell culture, the compound inhibits EV71 at a 50% effective concentration of 0.67 µM and a 50% cytotoxic concentration of 119.97 µM. When administered at 5 mg/kg in an EV71 mouse model, the compound reduced viral loads in various organs and completely prevented clinical symptoms and death. To study the antiviral mechanism and drug resistance, we selected escape mutant viruses by culturing EV71 with increasing concentrations of NITD008. Resistance mutations were reproducibly mapped to the viral 3A and 3D polymerase regions. Resistance analysis with recombinant viruses demonstrated that either a 3A or a 3D mutation alone could lead to resistance to NITD008. A combination of both 3A and 3D mutations conferred higher resistance, suggesting a collaborative interplay between the 3A and 3D proteins during viral replication. The resistance results underline the importance of combination therapy required for EV71 treatment. Importance: Human enterovirus 71 (EV71) has emerged as a major cause of viral encephalitis in children worldwide, especially in the Asia-Pacific region. Vaccines and antivirals are urgently needed to prevent and treat EV71 infections. In this study, we report the in vitro and in vivo efficacy of NITD008 (an adenosine analog) as an inhibitor of EV71. The efficacy results validated the potential of nucleoside analogs as antiviral drugs for EV71 infections. Mechanistically, we showed that mutations in the viral 3A and 3D polymerases alone or in combination could confer resistance to NITD008. The resistance results suggest an intrinsic interaction between viral proteins 3A and 3D during replication, as well as the importance of combination therapy for the treatment of EV71 infections.

Irradiation of Yarrowia lipolytica NRRL YB-567 creating novel strains with enhanced ammonia and oil production on protein and carbohydrate substrates.

Increased interest in sustainable production of renewable diesel and other valuable bioproducts is redoubling efforts to improve economic feasibility of microbial-based oil production. Yarrowia lipolytica is capable of employing a wide variety of substrates to produce oil and valuable co-products. We irradiated Y. lipolytica NRRL YB-567 with UV-C to enhance ammonia (for fertilizer) and lipid (for biodiesel) production on low-cost protein and carbohydrate substrates. The resulting strains were screened for ammonia and oil production using color intensity of indicators on plate assays. Seven mutant strains were selected (based on ammonia assay) and further evaluated for growth rate, ammonia and oil production, soluble protein content, and morphology when grown on liver infusion medium (without sugars), and for growth on various substrates. Strains were identified among these mutants that had a faster doubling time, produced higher maximum ammonia levels (enzyme assay) and more oil (Sudan Black assay), and had higher maximum soluble protein levels (Bradford assay) than wild type. When grown on plates with substrates of interest, all mutant strains showed similar results aerobically to wild-type strain. The mutant strain with the highest oil production and the fastest doubling time was evaluated on coffee waste medium. On this medium, the strain produced 0.12 g/L ammonia and 0.20 g/L 2-phenylethanol, a valuable fragrance/flavoring, in addition to acylglycerols (oil) containing predominantly C16 and C18 residues. These mutant strains will be investigated further for potential application in commercial biodiesel production.