Emerging Monkeypox Virus Sublineage C.1 Causing Community Transmission, Vietnam, 2023.

We studied a community cluster of 25 mpox cases in Vietnam caused by emerging monkeypox virus sublineage C.1 and imported into Vietnam through 2 independent events; 1 major cluster carried a novel APOBEC3-like mutation. Three patients died; all had advanced HIV co-infection. Viral evolution and its potential consequences should be closely monitored.

Enhancing plastic biodegradation process: strategies and opportunities.

Plastic biodegradation has emerged as a sustainable approach and green alternative in handling the ever-increasing accumulation of plastic wastes in the environment. The complete biodegradation of polyethylene terephthalate is one of the most recent breakthroughs in the field of plastic biodegradation. Despite the success, the effective and complete biodegradation of a wide variety of plastics is still far from the practical implementation, and an on-going effort has been mainly devoted to the exploration of novel microorganisms and enzymes for plastic biodegradation. However, alternative strategies which enhance the existing biodegradation process should not be neglected in the continuous advancement of this field. Thus, this review highlights various strategies which have shown to improve the biodegradation of plastics, which include the pretreatment of plastics using UV irradiation, thermal, or chemical treatments to increase the susceptibility of plastics toward microbial action. Alternative pretreatment strategies are also suggested and compared with the existing techniques. Besides, the effects of additives such as pro-oxidants, natural polymers, and surfactants on plastic biodegradation are discussed. In addition, considerations governing the biodegradation performance, such as the formulation of biodegradation medium, cell-free biocatalysis, and physico-chemical properties of plastics, are addressed. Lastly, the challenges and future prospects for the advancement of plastic biodegradation are also highlighted.

Validation and Application of a Molecular Detection System for Fusarium Wilt of Banana in China.

Fusarium wilt of banana is a devastating disease caused by Fusarium oxysporum f. sp. cubense (Foc). It has restricted the development of the banana industry worldwide and is particularly serious in China because of the large planting areas and special planting patterns. However, there is no rapid and accurate approach to detect the Foc strains that specifically occur in China because of the rich genetic diversity observed in this pathosystem. In this study, we evaluated the performance of 10 previously published PCR primer pairs on 103 representative Foc strains in China and neighboring countries and screened out a set of primers (Foc-specific primer pair SIX9-Foc-F/R, Foc R1-specific primer pair SIX6b-210-F/R, Foc R4-specific primer pair Foc-1/2, and Foc TR4-specific primer pair W2987F/R) suitable for the detection of Foc strains in China and the surrounding Southeast Asian countries. Moreover, we developed a molecular detection system to accurately identify the different physiological races of Foc. The findings of this study provide technical support for preventing and controlling the spread of Fusarium wilt of banana in the field in China.

Microbial biodegradation of recalcitrant synthetic dyes from textile-enriched wastewater by Fusarium oxysporum.

The present study reported the improvement of biological treatment for the removal of recalcitrant dyes including aniline blue, reactive black 5, orange II, and crystal violet in contaminated water. The biodegradation efficiency of Fusarium oxysporum was significantly enhanced by the addition of mediators and by adjusting the biomass density and nutrient composition. A supplementation of 1% glucose in culture medium improved the biodegradation efficiency of aniline blue, reactive black 5, orange II, and crystal violet by 2.24, 1.51, 4.46, and 2.1 folds, respectively. Meanwhile, the addition of mediators to culture medium significantly increased the percentages of total removal for aniline blue, reactive black 5, orange II, and crystal violet, reaching 86.07%, 68.29%, 76.35%, and 95.3%, respectively. Interestingly, the fungal culture supplemented with 1% remazol brilliant blue R boosted the biodegradation up to 97.06%, 89.86%, 91.38%, and 86.67% for aniline blue, reactive black 5, orange II, and crystal violet, respectively. Under optimal culture conditions, the fungal culture could degrade these synthetic dyes concentration up to 104 mg/L. The present study demonstrated that different recalcitrant dye types can be efficiently degraded using microorganism such as F. oxysporum.

Effects of Plant Elicitors on Growth and Gypenosides Biosynthesis in Cell Culture of Giao co lam (Gynostemma pentaphyllum).

Giao co lam (Gynostemma pentaphyllum (Thunb.) Makino) is used in Northeast and Southeast Asia countries for the treatment of various diseases, including hepatitis, diabetes, and cardiovascular disease. G. pentaphyllum saponins (gypenosides) are the major components responsible for the pharmacological activities. In this study, different concentrations of abiotic (25-200 µM methyl jasmonate-MeJA and salicylic acid-SA) or biotic elicitors (1-5 g/L yeast extract-YE and Fusarium biomass) were used as plant elicitors, in order to investigate their influences on cell growth and gypenosides accumulation in G. pentaphyllum suspension cells. Suspension cells were grown on a MS medium containing 2.0 mg/L KIN and 0.5 mg/L IBA, with initial inoculum sizes of 3 g and shaking speeds of 120 rpm for 18 days. Gypenoside and Rb1 contents were measured by colorimetric and HPLC methods. Among three elicitors, SA was suitable for gypenosides accumulation in individual treatment. The cell biomass had the same values in elicitated and control suspension cells. Gypenosides content in cells treated with 100 µM salicylic acid after 6 days of culture reached a maximum value of 79.721 mg gypenoside/g dry biomass (including 0.093 mg ginsenoside Rb1/mg dry weight), which was 2.18-folds higher than that of the natural product. The elicitation promises an efficiency strategy for the production gypenosides in Gynostemma pentaphyllum suspension cells.

Perspective of Spirulina culture with wastewater into a sustainable circular bioeconomy.

Spirulina biomass accounts for 30% of the total algae biomass production globally. In conventional process of Spirulina biomass production, cultivation using chemical-based culture medium contributes 35% of the total production cost. Moreover, the environmental impact of cultivation stage is the highest among all the production stages which resulted from the extensive usage of chemicals and nutrients. Thus, various types of culture medium such as chemical-based, modified, and alternative culture medium with highlights on wastewater medium is reviewed on the recent advances of culture media for Spirulina cultivation. Further study is needed in modifying or exploring alternative culture media utilising waste, wastewater, or by-products from industrial processes to ensure the sustainability of environment and nutrients source for cultivation in the long term. Moreover, the current development of utilising wastewater medium only support the growth of Spirulina however it cannot eliminate the negative impacts of wastewater. In fact, the recent developments in coupling with wastewater treatment technology can eradicate the negative impacts of wastewater while supporting the growth of Spirulina. The application of Spirulina cultivation in wastewater able to resolve the global environmental pollution issues, produce value added product and even generate green electricity. This would benefit the society, business, and environment in achieving a sustainable circular bioeconomy.

Optimization of culture conditions for gamma-aminobutyric acid production by newly identified Pediococcus pentosaceus MN12 isolated from 'mam nem', a fermented fish sauce.

This study was aimed to identify and optimize the culture conditions for gamma-aminobutyric acid (GABA) production by a lactic acid bacterium strain isolated from mam nem, a fermented fish sauce. Among the six isolates obtained from mam nem, the MN12 had the most potent GABA-producing capability. The strain was then identified to be Pedioccocus pentosaceus by employing MALDI-TOF-MS and phenylalanyl-tRNA synthase sequencing methods. The initial cell density of 5.106 CFU/mL, monosodium glutamate concentration of 60 mM, initial pH of 7, temperature of 45°C and cultivation time of 72 h were found to be the optimal culture conditions for highest production of GABA, reaching 27.9 ± 0.42 mM, by this strain. The cultivation conditions for GABA production by P. pentosaceus MN12 have been successfully optimized, providing a foundation for the development of fermented foods enriched with GABA.

Characterisation and antifungal activity of extracellular chitinase from a biocontrol fungus, Trichoderma asperellum PQ34.

Trichoderma species were known as biological control agents against phytopathogenic fungi because they produce a variety of chitinases. Chitinases are hydrolytic enzymes that break down glycosidic bonds in chitin, a major component of the cell walls of fungi. The present study shows that extracellular chitinase activity reached a maximum value of approximately 22 U/mL after 96 h of T. asperellum PQ34 strain culture. The optimal temperature and pH of enzyme are 40°C and 7, respectively, whereas the thermal and pH stability range from 25°C to 50°C and 4 to 10, respectively. Chitinase at 60 U/mL inhibited nearly completely in vitro growth of Colletotrichum sp. (about 95%) and Sclerotium rolfsii (about 97%). In peanut plants, 20 U/mL of chitinase significantly reduced the incidence of S. rolfsii infection compared to controls. The fungal infection incidence of seeds before germination and 30 days after germination was only 2.22% and 2.38%, while the control was 13.33% and 17.95%. Besides, chitinase from T. asperellum PQ34 can also prevent anthracnose that is caused by Colletotrichum sp. on both mango and chilli fruits up to 72 h after enzyme pre-treatment at 40 U/mL. In mango and chilli fruits infected with anthracnose, 40 U/mL dose of chitinase inhibited the growth of fungi after 96 h of treatment, the diameter of lesion was only 0.88 cm for mango and 1.45 cm for chilli, while the control was 1.67 cm and 2.85 cm, respectively.

Cloning, expression and characterization of catechol 1,2-dioxygenase from Burkholderia cepacia.

The present study reports on the cloning, expression and characterization of catechol 1,2-dioxygenase (CAT) of bacterial strains isolated from dioxin-contaminated soils in Vietnam. Two isolated bacterial strains DF2 and DF4 were identified as Burkholderia cepacia based on their 16S rRNA sequences. Their genes coding CAT was amplified with a specific pair of primers. Recombinant CAT (rCAT) was expressed in E. coli M15 cells and its activity was confirmed by the detection of cis,cis-muconic acid, a product from catechol, by high-performance liquid chromatography (HPLC) analysis. The rCAT of DF4 had an optimal pH and temperature of 7 and 30°C, respectively. Metal ions, such as Zn2+ and Mn2+, and surfactants, such as SDS, Tween 20 and Triton X100, strongly inhibited enzyme activity, while K+ slightly increased the activity.

Identification and Characterization of Genes in the Curcuminoid Pathway of Curcuma zedoaria Roscoe.

BACKGROUND: Curcuminoid genes have an important role in the biosynthesis of curcumin, a valuable bioactive compound, in Curcuma species. However, there have not been any reports of these genes in Curcuma zedoaria. OBJECTIVE: The present work reports on the isolation of genes encoding enzymes in curcuminoid metabolic pathway and their expression in C. zedoaria. METHOD: The primers were designed from untranslation regions of DCS, CURS1, CURS2 and CURS3 genes which are involved in curcuminoid biosynthesis in C. longa to isolate the corresponding fulllength genes in C. zedoaria. RT-PCR amplification and HPLC analysis are used to estimate the expression of genes and biosynthesis of curcumin in both rhizome and callus. RESULTS: The results showed that all four genes from C. zedoaria (named CzDCS, CzCURS1, CzCURS2 and CzCURS3) and C. longa have a high identity (approximately 99%) and lengths of genes from C. zedoaria are 1382, 1240, 1288 and 1265 nu, respectively. CzCURS1, 2 and 3 genes have one intron while CzDCS has two introns. RT-PCR amplification indicated that curcuminoid genes expressed mRNA in rhizome and callus of C. zedoaria. Curcumin, a major component of curcuminoids, was also found in callus by HPLC analysis. CONCLUSION: The sequence information of DCS and CURS1-3 genes in C. zedoaria will be very valuable for a subsequent study on the effects of elicitors on the transcription of genes involved in curcuminoid biosynthesis pathway.

Screening and Production of Manganese Peroxidase from Fusarium sp. on Residue Materials.

In this study, we report the manganese peroxidase production ability from a Fusarium sp. strain using an inexpensive medium of agriculture residues of either rice straw or wood chips as carbon source. The highest manganese peroxidase activity on rice straw medium and on wood chips was 1.76 U/mL by day 9 and 1.91 U/mL by day 12, respectively.

Effect of salicylic acid on expression level of genes related with isoprenoid pathway in centella (Centella asiatica (L.) Urban) cells.

In this study, we report the expression level of CaSQS, CabAS and CaCYS, the genes involved in phytosterol and triterpene metabolic pathway of centella (Centella asiatica (L.) Urban), in cells elicited with salicylic acid (50-200 µM). Reverse transcription-polymerase chain reaction (RT-PCR) and Northern blot analysis indicated CaSQS, CabAS, and CaCYS genes expressed in both the wild-type and cultured cells (with and without elicitation). In elicited cells, expressions of CaSQS, CabAS, and CaCYS genes showed strong dependence on salicylic acid concentration and elicitation day. The highest expression of CabAS gene was found in the cells elicited with 100 µM salicylic acid on day 10 of inoculation. Salicylic acid treatment (50-200 µM) decreased expression level of CaCYS and CaSQS genes in elicited cells compared with the control.

Characterization of a novel manganese dependent endoglucanase belongs in GH family 5 from Phanerochaete chrysosporium.

The cDNA encoding a putative glycoside hydrolase family 5, which has been predicted to be an endoglucanase (PcEg5A), was cloned from Phanerochaete chrysosporium and expressed in Pichia pastoris. PcEg5A contains a carbohydrate-binding domain and two important amino acids, E209 and E319, playing as proton donor and nucleophile in substrate catalytic domain. SDS-PAGE analysis indicated that the recombinant endoglucanase 5A (rPcEg5A) has a molecular size of 43 kDa which corresponds with the theoretical calculation. Optimum pH and temperature were found to be 4.5-6.0, and 50°C-60°C, respectively. Moreover, rPcEg5A exhibited maximal activity in the pH range of 3.0-8.0, whereas over 50% of activity still remained at 20°C and 80°C. rPcEg5A was stable at 60°C for 12 h incubation, indicating that rPcEg5A is a thermostable enzyme. Manganese ion enhanced the enzyme activity by 77%, indicating that rPcEg5A is a metal dependent enzyme. The addition of rPcEg5A to cellobiase (cellobiohydrolase and ß-glucosidase) resulted in a 53% increasing saccharification of NaOH-pretreated barley straw, whereas the glucose release was 47% higher than that cellobiase treatment alone. Our study suggested that rPcEg5A is an enzyme with great potential for biomass saccharification.

Putative endoglucanase PcGH5 from Phanerochaete chrysosporium is a ß-xylosidase that cleaves xylans in synergistic action with endo-xylanase.

A predicted endoglucanase gene (PcGH5) was cloned from Phanerochaete chysosporium, and expressed in Pichia pastoris. Although PcGH5 showed similarity with the conserved domains of a cellulase superfamily GH5, a ß-glucosidase/6-phospho-ß-glucosidase/ß-galactosidase superfamily, and an endoglucanase, recombinant PcGH5 exhibited a ß-xylosidase activity, rather than endoglucanase activity. Therefore, the predicted gene was named as PcXyl5. Further characterization of recombinant PcXyl5 showed not only catalysis of the hydrolysis of xylo-oligomers to xylose, but also displayed transglycosylation activity using alcohol as a receptor. Optimum pH of rPcXyl5 was found to be 5.5, whereas optimum temperature was 50°C. rPcXyl5 increased reducing sugar release of birchwood xylan, beechwood xylan, and arabinoxylan by 6.4%, 13%, 15.8%, respectively, in synergistic action with endo-xylanase. Interestingly, the late addition of rPcXyl5 into reaction with endo-xylanase resulted in a larger increase of reducing sugar release from pretreated barley straw that addition at the start or by treatment with endo-xylanases alone. The increases observed were 6.3% and 13.8%, respectively, showing a great potential application for hemicellulose saccharification.

Characterization of a recombinant bifunctional xylosidase/arabinofuranosidase from Phanerochaete chrysosporium.

A bifunctional xylosidase/arabinofuranosidase gene (PcXyl) was cloned from the cDNA library of Phanerochaete chrysosporium and further expressed in Pichia pastoris. Enzymatic assay indicated that P. pastoris produced rPcXyl at a level of 26,141 U l⁻¹. The xylosidase and arabinofuranosidase activities of rPcXyl were maximized, respectively, at pHs of 5.0 and 5.5 and temperatures of 45°C and 50°C. SDS-PAGE revealed a single band of purified rPcXyl of 83 kDa. Cu²âº and Zn²âº completely inhibited the enzyme activity of rPcXyl. The enzyme activity of rPcXyl was increased 151%, 126% and 123%, respectively, in the presence of glucose, xylose and arabinose at concentrations of 5 mM. rPcXyl hydrolyzed xylobiose to xylose and xylotriose to xylose and xylobiose, indicating rPcXyl acts as an exo-type enzyme. Additionally, rPcXyl enhanced xylose release from xylan substrates in synergy with rPcXynC.

Cloning and characterization of a thermostable endo-arabinanase from Phanerochaete chrysosporium and its synergistic action with endo-xylanase.

Putative arabinanase (PcARA) was cloned from cDNA of Phanerochaete chrysosporium. The gene sequencing indicated that PcARA consisted of 939 nucleotides that encodes for 312 amino acid arabinanase-polypeptide chain, including a signal peptide of 19 amino acids. Three-dimensional homology indicated that this enzyme is a five-bladed ß-propeller, belonging to glycosidase family 43 and its secondary structure is consisted of 24 ß-sheets. The PcARA-cDNA was expressed in Pichia pastoris using pPICZαC. SDS-PAGE of purified arabinanase showed a single band of 33 kDa that is very close to theoretical molecular mass of 33.9 kDa calculated by its amino acid content. Recombinant arabinanase (rPcARA) exhibited maximum activity at pH and temperature of 5.0 and 60 °C, respectively. End-product analysis of debranched arabinan hydrolysis by thin-layer chromatography indicated that rPcARA acted as endo-type. The synergistic action of rPcARA with recombinant xylanase resulted in 72 and 9.3 % release of total soluble sugar of arabinoxylan and NaOH-pretreated barley straw, respectively.

Cloning and characterization of a novel bifunctional acetyl xylan esterase with carbohydrate binding module from Phanerochaete chrysosporium.

The cDNA of acetyl xylan esterase 2 (PcAxe2) gene containing a carbohydrate binding module (CBM) sequence from Phanerochaete chrysosporium was cloned and expressed in Pichia pastoris. The recombinant PcAxe2 protein (rPcAxe2) was efficiently produced, reaching a maximum of 1058 U l(-1) after 6 days of cultivation. Molecular mass of the rPcAxe2 on SDS-PAGE was approximately 63 kDa under hyperglycosylation. Optimal activity of the purified rPcAxe2 enzyme was observed at pH and temperature of 7.0 and 30-35°C, respectively. In addition to acetyl xylan esterase activity, rPcAxe2 also exhibited a xylanase activity at an optimum pH and temperature of 5.0 and 80°C, respectively. The synergistic action of rPcAxe2 with rPcXynC on birchwood xylan, beechwood xylan and wheat arabinoxylan enhanced the total reducing soluble sugar.

Heterologous expression of endo-1,4-beta-xylanaseC from Phanerochaete chrysosporium in Pichia pastoris.

The cDNA of endo-1,4-ß-xylanaseC, isolated from Phanerochaete chrysosporium, was expressed in Pichia pastoris, under the control of the alcohol oxidase I promoter. Using either the intrinsic leader peptide of xylanaseC or the α-factor signal peptide of Saccharomyces cerevisiae, xylanaseC is efficiently secreted into the medium, at a maximum concentration of 2500 U·l(-1).

Heterologous Expression of Endo-1,4-beta-xylanaseA from Phanerochaete chrysosporium in Pichia pastoris.

The cDNA of endo-1,4-ß-xylanaseA, isolated from Phaenerocheate chrysosporium was expressed in Pichia pastoris. Using either the intrinsic leader peptide of XynA or the α-factor signal peptide of Saccharomyces cerevisiae, xylanaseA is efficiently secreted into the medium at maximum concentrations of 1,946 U/L and 2,496 U/L, respectively.

Trichoderma asperellumChi42 Genes Encode Chitinase.

Four Trichoderma strains (CH2, SH16, PQ34, and TN42) were isolated from soil samples collected from Quang Tri and Thua Thien Hue provinces in Vietnam. The strains exhibited high chitinolytic secretion. Strain PQ34 formed the largest zone of chitinase-mediated clearance (> 4 cm in diameter) in agar containing 1% (w/v) colloidal chitin. Analysis of the internal transcribed spacer regions of these strains indicated that they were Trichoderma asperellum. The molecular weights of the chitinases were approximately 42 kDa. Chitinase genes (chi42) of T. asperellum strains TN42, CH2, SH16, and PQ34 were 98~99% homologous to the ech42 gene of T. harzianum CB-Pin-01 (accession No. DQ166036). The deduced amino acid sequences of both T. asperellum strains SH16 and TN42 shared 100% similarity.