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Fertilizer is applied widely to improve the productivity of plantations. Traditionally, fertilization is conducted in spring and/or in the early rainy season, and it is believed to support the growth of planted trees in the growing season. Little attention to date has been paid on identification of the optimal timing of fertilization and fertilizer dose. In this study, application of the fine root monitoring technique in identifying optimal fertilization timing for an Acacia plantation in Vietnam is described. The study used two fertilizer doses (100 and 200 g NPK/tree) and three fertilization timings (in spring; in the early rainy season; and based on the fine root monitoring technique to identify when the fine roots reach their growth peak). As expected fertilization timings significantly affected growth and above-ground biomass (AGB) of the plantation. Fertilization based on the fine root monitoring technique resulted in the highest growths and AGB, followed by fertilization in the early rainy season and then in spring. Applying fertilizer at 200 g NPK/tree based on the fine root monitoring technique increased diameter at breast height (DBH) by 16%, stem height by 8%, crown diameter (Dc) by 16%, and AGB by 40% as compared to early rainy season fertilization. Increases of 32% DBH, 23% stem height, 44% Dc, and 87% AGB were found in fertilization based on fine root monitoring technique compared to spring fertilization. This study concluded that forest growers should use the fine root monitoring technique to identify optimal fertilization timing for higher productivity.

Background: Diarrheagenic Escherichia coli (DEC) is a group of bacterial pathogens that causes life-threatening diarrhea in children in developing countries. However, there is limited information on the characteristics of DEC isolated from patients in these countries. A detailed genomic analysis of 61 DEC-like isolates from infants with diarrhea was performed to clarify and share the characteristics of DEC prevalent in Vietnam. Principal findings: DEC was classified into 57 strains, including 33 enteroaggregative E. coli (EAEC) (54.1%), 20 enteropathogenic E. coli (EPEC) (32.8%), two enteroinvasive E. coli (EIEC) (3.3%), one enterotoxigenic E. coli (ETEC), and one ETEC/EIEC hybrid (1.6% each), and surprisingly into four Escherichia albertii strains (6.6%). Furthermore, several epidemic DEC clones showed an uncommon combination of pathotypes and serotypes, such as EAEC Og130:Hg27, EAEC OgGp9:Hg18, EAEC OgX13:H27, EPEC OgGp7:Hg16, and E. albertii EAOg1:HgUT. Genomic analysis also revealed the presence of various genes and mutations associated with antibiotic resistance in many isolates. Strains that demonstrate potential resistance to ciprofloxacin and ceftriaxone, drugs recommended for treating childhood diarrhea, accounted for 65.6% and 41%, respectively. Significance: Our finding indicate that the routine use of these antibiotics has selected resistant DECs, resulting in a situation where these drugs do not provide in therapeutic effects for some patients. Bridging this gap requires continuous investigations and information sharing regarding the type and distribution of endemic DEC and E. albertii and their antibiotic resistance in different countries. Author summary: Diarrhea is a leading cause of morbidity and mortality in children under five years of age in developing countries, and diarrheagenic Escherichia coli (DEC) is a group of bacterial pathogens that cause a wide variety of intestinal diseases. To control the epidemic of DECs, it is necessary to understand the characteristics of prevalent strains in each region and propose appropriate treatment methods for them. This study reports detailed genomic analysis results of DEC-like strains isolated from infant diarrhea patients in Vietnam. The results suggested that many of the DECs prevalent in this country are uncommon types, and that Escherichia albertii, an emerging diarrheal pathogen, is the cause of diarrhea. Furthermore, comprehensive genome analysis revealed that these DECs are developing serious drug resistance. We believe that the results of this study will be the basis for improving treatment methods for patients with diarrhea and for tracking the evolution of this pathogenic group. [ABSTRACT FROM AUTHOR]

Solar steam generation (SSG) is promising for clean water production owing to low cost, simple operation, and green technology. This work investigates the fabrication of bioinspired photothermal (BIPT) material by sputtering a copper layer on Phanera purpurea (PP) leaf for application in SSG systems. It is observed that the light absorbance of the BIPT material exceeds 92% in the wavelength region of 300–2500 nm. This is due to the light trapping effect caused by multi‐internal reflection inside the Cu‐coated leaf nanostructure. The BIPT material exhibits a low thermal conductivity and easy cleaning properties as a result of PP leaf surface features. A novel strategy in this work is the design of the BIPT material‐based SSG system to recycle the radiative heat loss for evaporation. The developed SSG system results in a solar steam efficiency of 83.7% and a water evaporation rate of 1.45 kg m−2 h−1 under 1 sun. It is also applied in seawater desalination and the produced water satisfies the WHO standards for ion concentrations in clean water. Because of the simple procedure and low cost, the sputtering Cu on the PP leaf can be potentially used in the mass production of BIPT material for seawater desalination. [ABSTRACT FROM AUTHOR]

Vegetative propagation method such as cutting, provides uniform plant materials from mother plants. The effect of medium and exogenous hormone pretreatment on rooting were studied for golden camellia - Camellia impressinervis, a tree species which is used for healthcare. The results showed that different concentrations of exogenous hormones IBA (Indole-3-butyric acid), IAA (Indole-3-acetic acid), significantly affected rooting efficiency. Cuttings treated with IBA and IAA had significantly higher rooting percentage than control (54.2 %). Higher rooting efficiency was obtained with IBA, which resulted in highest rooting percentage of 91.4 % at 4 months of growth by using concentration of 0.5 % (by weight). Hormone types and their concentrations did not affect mean root number (MRN) and mean root length (MRL). Rooting media significantly affected rooting efficiency, MRN per cutting, and MRL. Using medium of 100 % sand resulted in highest rooting percentage ( 91.4 %), roots per cutting (4.2) and MRL (5.4 cm) at 4 months of growth. It is concluded that to produce seedlings for C. impressinervis by cuttings, rooting medium of 100 % sand should be used and cuttings should be pretreated by 0.5 % IBA. In addition, cutting management is also important for rooting efficiency. It must be controlled with humidity of > 95 % and temperature of < 27 °C. [ABSTRACT FROM AUTHOR]

Tigecycline is a last-resort antimicrobial against carbapenemase-producing Enterobacterales (CPE). However, mobile tigecycline resistance genes, tet (X) and tmexCD-toprJ , have emerged in China and have spread possibly worldwide. Tet(X) family proteins function as tigecycline-inactivating enzymes, and TMexCD-TOprJ complexes function as efflux pumps for tigecycline. Here, to the best of our knowledge we report a CPE isolate harboring both emerging tigecycline resistance factors for the first time. A carbapenem- and tigecycline-resistant Klebsiella aerogenes strain, NUITM-VK5, was isolated from an urban drainage in Vietnam in 2021, and a plasmid, pNUITM-VK5&#95;mdr, cocarrying tet (X) and tmexCD3-toprJ3 along with the carbapenemase gene bla NDM-4 was identified in NUITM-VK5. pNUITM-VK5&#95;mdr was transferred to Escherichia coli by conjugation and simultaneously conferred high-level resistance against multiple antimicrobials, including carbapenems and tigecycline. An efflux pump inhibitor reduced TMexCD3-TOprJ3-mediated tigecycline resistance, suggesting that both tigecycline resistance factors independently and additively contribute to the high-level resistance. The plasmid had the IncX3 and IncC replicons and was estimated to be a hybrid of plasmids with different backbones. Unlike IncX3 plasmids, IncC plasmids are stably maintained in an extremely broad range of bacterial hosts in humans, animals, and the environment. Thus, the future global spread of multidrug resistance plasmids such as pNUITM-VK5&#95;mdr poses a public health crisis. IMPORTANCE Tigecycline is important as a last-resort antimicrobial and effective against antimicrobial-resistant bacteria, such as carbapenem-producing Enterobacterales (CPE), whose infections are difficult to treat with antimicrobials. Since 2019, mobile tigecycline resistance genes, tet (X) and tmexCD-toprJ , and their variants have been reported mainly from China, and it has become important to understand their epidemiological situation and detailed genetic mechanisms. In this study, we identified a bacterial isolate coharboring tet (X) and tmexCD-toprJ on the same plasmid. A Klebsiella aerogenes isolate in Vietnam carried both these tigecycline resistance genes on a transferable plasmid leading to high-level resistance to multiple clinically important antimicrobials, including carbapenem and tigecycline, and could actually transfer the plasmid to other bacteria. The spread of such a multidrug resistance plasmid among bacterial pathogens should be of great concern because there are few antimicrobials to combat bacteria that have acquired the plasmid.