Quantification of plant surface metabolites by matrix‐assisted laser desorption–ionization mass spectrometry imaging: glucosinolates on Arabidopsis thaliana leaves

The localization of metabolites on plant surfaces has been problematic because of the limitations of current methodologies. Attempts to localize glucosinolates, the sulfur‐rich defense compounds of the order Brassicales, on leaf surfaces have given many contradictory results depending on the method employed. Here we developed a matrix‐assisted laser desorption–ionization (MALDI) mass spectrometry protocol to detect surface glucosinolates on Arabidopsis thaliana leaves by applying the MALDI matrix through sublimation. Quantification was accomplished by spotting glucosinolate standards directly on the leaf surface. The A. thaliana leaf surface was found to contain approximately 15 nmol of total glucosinolate per leaf with about 50 pmol mm^?2 on abaxial (bottom) surfaces and 15–30 times less on adaxial (top) surfaces. Of the major compounds detected, 4‐methylsulfinylbutylglucosinolate, indol‐3‐ylmethylglucosinolate, and 8‐methylsulfinyloctylglucosinolate were also major components of the leaf interior, but the second most abundant glucosinolate on the surface, 4‐methylthiobutylglucosinolate, was only a trace component of the interior. Distribution on the surface was relatively uniform in contrast to the interior, where glucosinolates were distributed more abundantly in the midrib and periphery than the rest of the leaf. These results were confirmed by two other mass spectrometry‐based techniques, laser ablation electrospray ionization and liquid extraction surface analysis. The concentrations of glucosinolates on A. thaliana leaf surfaces were found to be sufficient to attract the specialist feeding lepidopterans Plutella xylostella and Pieris rapae for oviposition. The methods employed here should be easily applied to other plant species and metabolites.     

Interstitial lactate,lactate/pyruvate and glucose in rat muscle before,during and in the recovery from global hypoxia

Background

Hypoxia results in an imbalance between oxygen supply and oxygen consumption. This study utilized microdialysis to monitor changes in the energy-related metabolites lactate, pyruvate and glucose in rat muscle before, during and after 30 minutes of transient global hypoxia. Hypoxia was induced in anaesthetised rats by reducing inspired oxygen to 6% O₂ in nitrogen.

Results

Basal values for lactate, the lactate/pyruvate ratio and glucose were 0.72 ± 0.04 mmol/l, 10.03 ± 1.16 and 3.55 ± 0.19 mmol/l (n = 10), respectively. Significant increases in lactate and the lactate/pyruvate ratio were found in the muscle after the induction of hypoxia. Maximum values of 2.26 ± 0.37 mmol/l for lactate were reached during early reperfusion, while the lactate/pyruvate ratio reached maximum values of 35.84 ± 7.81 at the end of hypoxia. Following recovery to ventilation with air, extracellular lactate levels and the lactate/pyruvate ratio returned to control levels within 30-40 minutes. Extracellular glucose levels showed no significant difference between hypoxia and control experiments.

Conclusions

In our study, the complete post-hypoxic recovery of metabolite levels suggests that metabolic enzymes of the skeletal muscle and their related cellular components may be able to tolerate severe hypoxic periods without prolonged damage. The consumption of glucose in the muscle in relation to its delivery seems to be unaffected.

     

Regional Variation in Pig Farmer Awareness and Actions Regarding Japanese Encephalitis in Nepal: Implications for Public Health Education

Japanese encephalitis (JE) is a mosquito-borne zoonotic disease that has pigs as the major amplifying hosts. It is the most important cause of viral encephalitis in people in Nepal and is spreading in its geographic distribution in that country. Pig farming is increasing in Nepal due to reducing cultural biases against pigs and government programs to support pig farming for poverty alleviation. Major strategies for JE prevention and control include education, vector control, and immunization of people and pigs. This study used a survey of 400 pig farmers in 4 areas of Nepal with different JE and pig farming histories to explore regional variations in farmer awareness and actions towards JE, the association of awareness and actions with farm and farmer variables, and the implications of these associations for public health education. Exposure to JE risk factors was common across pig farms and pig farming districts but there were significant district level differences in knowledge and practices related to on-farm JE risk reduction. Social factors such as literacy, gender, and cultural practices were associated with farmer attitudes, knowledge and practices for JE control. JE vaccine uptake was almost non-existent and mosquito control steps were inconsistently applied across all 4 districts. Income was not a determining factor of the differences, but all farmers were very poor. The low uptake of vaccine and lack of infrastructure or financial capacity to house pigs indoors or away from people suggest that farmer personal protection should be a priority target for education in Nepal. This study re-enforces the need to attack root causes of people’s personal disease prevention behaviours and take into account local variation in needs and capacities when designing health or agriculture education programs.     

Tebuconazole Sorption in Contrasting Soil Types

This study investigates the sorption of tebuconazole in contrasting soil types (Rendzic Leptosol, Haplic Arenosol, and Haplic Cambisol). Tebuconazole was used both as an analytical-grade chemical and as a commercial product. Sorption experiments were performed using the batch equilibrium approach. The sorption of analytical-grade tebuconazole in soils was lower compared to the commercial product, with the exception of the Cambisol. The highest sorption was observed for the Cambisol regardless of the tebuconazole form. In the experiment with the commercial formula containing tebuconazole, a higher sorption was observed for the Leptosol compared to the Arenosol; the experiment with analytical-grade tebuconazole showed an opposite trend. The differences in sorption of the commercially available and analytical-grade tebuconazole can be attributed to the additives present in the commercial product. Based on the obtained results, tebuconazole sorption is mainly influenced by soil organic matter and the mineralogical composition, but fungicide composition plays an important role as well. Additives present in the commercial products support fungicide sorption in soils. These findings confirm that tebuconazole is adsorbed in soils with high contents of organic matter and clay minerals and its application to such soils should not lead to risks associated with fungicide leaching.     

Regulation of Auxin Homeostasis and Gradients in Arabidopsis Roots through the Formation of the Indole-3-Acetic Acid Catabolite 2-Oxindole-3-Acetic Acid

The native auxin, indole-3-acetic acid (IAA), is a major regulator of plant growth and development. Its nonuniform distribution between cells and tissues underlies the spatiotemporal coordination of many developmental events and responses to environmental stimuli. The regulation of auxin gradients and the formation of auxin maxima/minima most likely involve the regulation of both metabolic and transport processes. In this article, we have demonstrated that 2-oxindole-3-acetic acid (oxIAA) is a major primary IAA catabolite formed in Arabidopsis thaliana root tissues. OxIAA had little biological activity and was formed rapidly and irreversibly in response to increases in auxin levels. We further showed that there is cell type–specific regulation of oxIAA levels in the Arabidopsis root apex. We propose that oxIAA is an important element in the regulation of output from auxin gradients and, therefore, in the regulation of auxin homeostasis and response mechanisms.     

Biogenic nanoporous silicon carrier improves the efficacy of buparvaquone against resistant visceral leishmaniasis

Visceral leishmaniasis is a vector-borne protozoan infection that is fatal if untreated. There is no vaccination against the disease, and the current chemotherapeutic agents are ineffective due to increased resistance and severe side effects. Buparvaquone is a potential drug against the leishmaniases, but it is highly hydrophobic resulting in poor bioavailability and low therapeutic efficacy. Herein, we loaded the drug into silicon nanoparticles produced from barley husk, which is an agricultural residue and widely available. The buparvaquone-loaded nanoparticles were several times more selective to kill the intracellular parasites being non-toxic to macrophages compared to the pure buparvaquone and other conventionally used anti-leishmanial agents. Furthermore, the in vivo results revealed that the intraperitoneally injected buparvaquone-loaded nanoparticles suppressed the parasite burden close to 100%. By contrast, pure buparvaquone suppressed the burden only by 50% with corresponding doses. As the conclusion, the biogenic silicon nanoparticles are promising carriers to significantly improve the therapeutic efficacy and selectivity of buparvaquone against resistant visceral leishmaniasis opening a new avenue for low-cost treatment against this neglected tropical disease threatening especially the poor people in developing nations.     

Review of the subgenus Polyphylla (Granida) from continental Asia (Coleoptera, Scarabaeidae, Melolonthinae)

A review of Polyphylla Harris, 1841, species belonging to the subgenus Granida Motschulsky, 1861, from continental Asia is presented. One new species is described from Thailand: Polyphylla (Granida) simonisp. n.Polyphylla (Granida) nikodymi de Wailly, 1993, is recorded from Thailand for the first time. Polyphylla (Granida) minor Nomura, 1977, is recorded from Yunnan (China) for the first time. The previously unknown female of Polyphylla (Granida) phongsali Zídek, 2006, is described.     

Gaps and perspectives of pathotype and race determination in <Emphasis Type="Italic">Golovinomyces cichoracearum</Emphasis> and <Emphasis Type="Italic">Podosphaera xanthii</Emphasis>

Golovinomyces cichoracearum and Podosphaera xanthii (family Erysiphaceae) are the most important species causing cucurbit powdery mildew (CPM), a serious disease of field and greenhouse cucurbits. Both species are highly variable in their pathogenicity and virulence, as indicated by the existence of large number of different pathotypes and races. Various independent systems of CPM pathotype and race determinations and denominations are used worldwide. CPM pathotype identification is based on intergeneric and interspecific differences in host-CPM interactions. The most commonly used set of CPM pathotype differentials includes one genotype from four species representing three agriculturally important cucurbit genera plus two genotypes from a fifth species, melon Cucumis melo L. CPM races are characterized by specialization on different cultivars or lines of one host species and have, to date, been differentiated only on melon (C. melo L.). The most frequently used set of melon differentials includes 11 genotypes that can differentiate CPM races originating from melon and other cucurbits, e.g., cucumber, Cucurbita spp., and watermelon. In this paper, we critically review the current state, gaps, and perspectives in our understanding of pathogenicity variation in these two CPM pathogens at the pathotype and race levels.     

Deficiency of mast cells in coronary artery endarterectomy of male patients with type 2 diabetes

Background

Increased fasting plasma glucose (FPG), which includes impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and diabetes, is a risk factor for arterial stiffness. While IFG is widely accepted as a cardiovascular risk factor, recent studies have argued that subjects with high-normal glucose level were characterized by a high incidence of cardiovascular disease. The purpose of this study is to investigate the relationship between FPG and arterial stiffness in non-diabetic healthy subjects.

Methods

We recruited 697 subjects who visited the health promotion center of a university hospital from May 2007 to August 2008. Age, sex, body mass index (BMI), resting heart rate, smoking habits, alcohol intake, exercise, blood pressure, medical history, FPG, lipid profile, high sensitivity C-reactive protein (hs-CRP), and Brachial-ankle pulse wave velocity (ba-PWV) were measured. We performed correlation and multiple linear regression analyses to divide the research subjects into quartiles: Q1(n = 172), 65 mg/dL ≤FPG < 84 mg/dL; Q2(n = 188), 84 mg/dL ≤FPG < 91 mg/dl; Q3(n = 199), 91 mg/dL ≤FPG < 100 mg/dL; Q4(n = 138), 100 mg/dL ≤FPG < 126 mg/dL.

Results

FPG has an independent, positive association with ba-PWV in non-diabetic subjects after correcting for confounding variables, including age, sex, BMI, blood pressure, resting heart rate, hs-CRP, lipid profile, and behavioral habits. The mean ba-PWV of the high-normal glucose group (Q3, 1384 cm/s) was higher than that of the low-normal glucose group (1303 ± 196 cm/s vs.1328 ± 167 cm/s, P < 0.05). The mean ba-PWV value in the IFG group (1469 ± 220 cm/s) was higher than that in the normoglycemic group (P < 0.05, respectively).

Conclusions

An increase in FPG, even within the normal range, was associated with aggravated arterial stiffness. Further research is needed to determine the glycemic target value for the prevention of arterial stiffness in clinical and public health settings.