Prediction of macronutrients in plant leaves using chemometric analysis and wavelength selection

Purpose: Fast and real-time prediction of leaf nutrient concentrations can facilitate decision-making for fertilisation regimes on farms and address issues raised with over-fertilisation. Cacao (Theobroma cacao L.) is an important cash crop and requires nutrient supply to maintain yield. This project aimed to use chemometric analysis and wavelength selection to improve the accuracy of foliar nutrient prediction. Materials and methods: We used a visible-near infrared (400–1000 nm) hyperspectral imaging (HSI) system to predict foliar calcium (Ca), potassium (K), phosphorus (P) and nitrogen (N) of cacao trees. Images were captured from 95 leaf samples. Partial least square regression (PLSR) models were developed to predict leaf nutrient concentrations and wavelength selection was undertaken. Results and discussion: Using all wavelengths, Ca (R = 0.76, RMSE = 0.28), K (R = 0.35, RMSE = 0.46), P (R = 0.75, RMSE = 0.019) and N (R = 0.73, RMSE = 0.17) were predicted. Wavelength selection increased the prediction accuracy of Ca (R = 0.79, RMSE = 0.27) and N (R = 0.74, RMSE = 0.16), while did not affect prediction accuracy of foliar K (R = 0.35, RMSE = 0.46) and P (R = 0.75, RMSE = 0.019). Conclusions: Visible-near infrared HSI has a good potential to predict Ca, P and N concentrations in cacao leaf samples, but K concentrations could not be predicted reliably. Wavelength selection increased the prediction accuracy of foliar Ca and N leading to a reduced number of wavelengths involved in developed models. 2 2 2 2 2 2 2 2 CV CV CV CV CV CV CV CV CV CV CV CV CV CV CV C

Soil-plant nitrogen isotope composition and nitrogen cycling after biochar applications

Biochar has strong potential to improve nitrogen (N) use efficiency in both agricultural and horticultural systems. Biochar is usually co-applied with full rates of fertiliser. However, the extent to which N cycling can be affected after biochar application to meet plant N requirement remains uncertain. This study aimed to explore N cycling up to 2 years after biochar application. We applied pine woodchip biochar at 0, 10 and 30 t ha (B0, B10, B30, respectively) in a macadamia orchard and evaluated the N isotope composition (δ N) of soil, microbial biomass and macadamia leaves. Soil total N (TN) and inorganic N pools were also measured up to 2 years after biochar application. Biochar did not alter soil TN but soil NO -N increased at months 12 and 24 after biochar application. Soil NO -N concentrations were always over ideal levels of 15 μg g in B30 throughout the study. Stepwise regression indicated that foliar δ N decreases after biochar application were explained by increased NO -N concentrations in B30. Foliar TN and photosynthesis were not affected by biochar application. The soil in the high rate biochar plots had excess NO -N concentrations (over 30 μg g ) from month 20 onwards. Therefore, N fertiliser applications could be adjusted to prevent excessive N inputs and increase farm profitability. −1 15 − − −1 15 − − −1 3 3 3

Biological nitrogen fixation by two Acacia species and associated root-nodule bacteria in a suburban Australian forest subjected to prescribed burning

Purpose: Prescribed burning is a forest management practice which can lead to nitrogen (N)-limited conditions. This study aimed to explore whether biological N fixation (BNF) remained the main source of N acquisition for two understorey Acacia species in a Eucalyptus-dominated suburban forest of subtropical Australia, 3 to 6 years after prescribed burning. Root-nodule bacteria associated with these acacias were also characterised to unravel the differences in rhizobial communities between sites and species. Material and methods: Two sites, burned 3 and 6 years before sample collection, were selected within a dry subtropical forest of south-east Queensland, Australia. Leaves were collected from individuals of Acacia disparrima and A. leiocalyx at each site to determine leaf total carbon (C) and N content, C and N isotope composition (δ C and δ N) and the percentage of N derived from atmospheric N . Nodules were harvested from both acacia species at each site to isolate root nodule bacteria. Bacterial isolates were processed for 16S rDNA gene sequencing. Results and discussion: Generally, no differences were found in plant physiological variables between the two acacia species. Six years after the fire, both species still depended upon BNF for their N supply, with a higher dependence in winter than in summer. Fire, although of low intensity, was likely to have created a N-limited environment which induced the reliance of legumes on BNF. Root nodule bacteria were dominated by non-rhizobial endophytes, mainly from the Firmicutes phylum. No difference in nodule bacterial diversity was found between sites. The relative abundance of rhizobial genera varied amongst plant species and sites, with a shift in dominance from Bradyrhizobium to Rhizobium species between sites 1 and 2. Conclusions: Our results show that even 6 years after burning, ecosystem remained under N stress and BNF was still the main mechanism for N acquisition by the understorey legumes. 2 2 13 1

Synthesis and bioactivities of diamide derivatives containing a phenazine-1-carboxamide scaffold

<p>Taking natural product phenazine-1-carboxamide (PCN) as a lead compound, a series of novel phenazine-1-carboxylic acid diamide derivatives were designed and synthesised. Their structures were confirmed by ¹H-NMR and HRMS. The bioassays showed that some of the target compounds exhibited promising <i>in vitro</i> fungicidal activities, and exhibited excellent and selective herbicidal activities. Particularly, compounds <b>c</b>, <b>h</b>, <b>o</b> and <b>s</b> displayed root length inhibition activities against <i>barnyard grass</i> with the rate of more than 80%. Compound <b>c</b> exhibited the best activity among all the target compounds against <i>barnyard grass</i> stalk length with the IC₅₀ value of 0.158 mmol/L, and compound <b>o</b> exhibited the best and wide spectrum inhibition against <i>barnyard grass</i> root length and <i>rape</i> in both root length and stalk length herbicidal activities with its IC₅₀ values of 0.067, 0.048 and 0.059 mmol/L respectively. The analysis of preliminary Structure-Activity Relationships provides the theoretical basis for further design of phenazine-1-carboxylic acid.</p

Association of the NOS3 polymorphism (rs1799983) with DVT when stratified by surgery type.

*<p><i>p</i> was considered statistically significant.</p

Association of the NOS3 polymorphism (rs1799983) with DVT when stratified by hypertension status.

*<p><i>p</i> was considered statistically significant.</p

Association of the NOS3 polymorphism (rs1799983) with DVT when stratified by gender.

*<p><i>p</i> was considered statistically significant.</p

Subject characteristics.

*<p><i>p</i> was considered statistically significant.</p

Combining metaphase cytogenetics with single nucleotide polymorphism arrays can improve the diagnostic yield and identify prognosis more precisely in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) encompass a group of heterogeneous haematopoietic stem cell malignancies characterised by ineffective haematopoiesis, cytological aberrations, and a propensity for progression to acute myeloid leukaemia. Diagnosis and disease prognostic stratification are much based on genomic abnormalities. The traditional metaphase cytogenetics analysis (MC) can detect about 40–60% aberrations. Single-nucleotide polymorphism arrays (SNP-A) karyotyping can detect copy number variations with a higher resolution and has a unique advantage in detection of copy number neutral loss of heterozygosity (CN-LOH). Combining these two methods may improve the diagnostic efficiency and accuracy for MDS. We retrospectively analysed the data of 110 MDS patients diagnosed from January 2012 to December 2019 to compare the detection yield of chromosomal abnormalities by MC with by SNP-A, and the relationship between chromosomal abnormalities and prognosis. Our results showed that SNP-A improved the detection yield of chromosomal aberrations compared with MC (74.5 vs. 55.5%, p 65 years, bone marrow blasts ≥5%, with acquired CN-LOH, new aberrations detected by SNP-A, TGA value > the median (81.435 Mb), higher risk by IPSS-R-MC, higher risk by IPSS-R-SNP-A all had poorer prognosis. More critically, multivariable analysis showed that age >65 years and higher risk by IPSS-R-SNP-A were independent predictors of inferior OS in MDS patients. The combination of MC and SNP-A based karyotyping can further improve the diagnostic yield and provide more precise prognostic stratification in MDS patients. However, SNP-A may not completely replace MC because of its inability to detect balanced translocation and to detect different clones. From a practical point of view, we recommend the concurrent use of SNP-A and MC in the initial karyotypic evaluation for MDS patients on diagnosis and prognosis stratification.KEY MESSAGESSNP-A based karyotyping can further improve the MDS diagnostic yield and provide more precise prognostic stratification in MDS patients.Acquired CN-LOH is a characteristic chromosomal aberration of MDS, which should be integrated to the diagnostic project of MDS.The concurrent use of SNP-A and MC in the initial karyotypic evaluation for MDS patients can be recommended. SNP-A based karyotyping can further improve the MDS diagnostic yield and provide more precise prognostic stratification in MDS patients. Acquired CN-LOH is a characteristic chromosomal aberration of MDS, which should be integrated to the diagnostic project of MDS. The concurrent use of SNP-A and MC in the initial karyotypic evaluation for MDS patients can be recommended.</p

Application of ¹H NMR Spectroscopy-Based Metabolomics to Sera of Tuberculosis Patients

Nuclear magnetic resonance (NMR) spectroscopy is an ideal platform for the metabolic analysis of biofluids due to its high reproducibility, nondestructiveness, nonselectivity in metabolite detection, and the ability to simultaneously quantify multiple classes of metabolites. Tuberculosis (TB) is a chronic wasting inflammatory disease characterized by multisystem involvement, which can cause metabolic derangements in afflicted patients. In this study, we combined multivariate pattern recognition (PR) analytical techniques with ¹H NMR spectroscopy to explore the metabolic profile of sera from TB patients. A total of 77 serum samples obtained from patients with TB (<i>n</i> = 38) and healthy controls (<i>n</i> = 39) were investigated. Orthogonal partial least-squares discriminant analysis (OPLS-DA) was capable of distinguishing TB patients from controls and establishing a TB-specific metabolite profile. A total of 17 metabolites differed significantly in concentration between the two groups. Serum samples from TB patients were characterized by increased concentrations of 1-methylhistidine, acetoacetate, acetone, glutamate, glutamine, isoleucine, lactate, lysine, nicotinate, phenylalanine, pyruvate, and tyrosine, accompanied by reduced concentrations of alanine, formate, glycine, glycerolphosphocholine, and low-density lipoproteins relative to control subjects. Our study reveals the metabolic profile of sera from TB patients and indicates that NMR-based methods can distinguish TB patients from healthy controls. NMR-based metabolomics has the potential to be developed into a novel clinical tool for TB diagnosis or therapeutic monitoring and could contribute to an improved understanding of disease mechanisms