A novel kinase regulates dietary restriction‐mediated longevity in Caenorhabditis elegans

Although dietary restriction (DR) is known to extend lifespan across species, from yeast to mammals, the signalling events downstream of food/nutrient perception are not well understood. In Caenorhabditis elegans, DR is typically attained either by using the eat‐2 mutants that have reduced pharyngeal pumping leading to lower food intake or by feeding diluted bacterial food to the worms. In this study, we show that knocking down a mammalian MEKK3‐like kinase gene, mekk‐3 in C. elegans, initiates a process similar to DR without compromising food intake. This DR‐like state results in upregulation of beta‐oxidation genes through the nuclear hormone receptor NHR‐49, a HNF‐4 homolog, resulting in depletion of stored fat. This metabolic shift leads to low levels of reactive oxygen species (ROS), potent oxidizing agents that damage macromolecules. Increased beta‐oxidation, in turn, induces the phase I and II xenobiotic detoxification genes, through PHA‐4/FOXA, NHR‐8 and aryl hydrocarbon receptor AHR‐1, possibly to purge lipophilic endotoxins generated during fatty acid catabolism. The coupling of a metabolic shift with endotoxin detoxification results in extreme longevity following mekk‐3 knock‐down. Thus, MEKK‐3 may function as an important nutrient sensor and signalling component within the organism that controls metabolism. Knocking down mekk‐3 may signal an imminent nutrient crisis that results in initiation of a DR‐like state, even when food is plentiful.     

Honey Pollen: Using Melissopalynology to Understand Foraging Preferences of Bees in Tropical South India

The aim of the study was to use melissopalynology to delineate the foraging preferences of bees in tropical environs. This was done by comparing pollen spectra obtained from the same hives every three months for three years at four sampling locations (in two sites) within a confined landscape mosaic. If melissopalynology is highly replicable, the spatial variation of the pollen spectrum from the honey samples would be much more than the temporal (inter-annual) variations. In other words, given the three factors, Month, Year and Location, honey pollen from different Locations, in a given Year and Month, would be much less similar than samples from different Years, in a given Location and Month. We then determined how the factors, Month, Year and Location, influenced the pollen influx of honey. The pollen analyses of the 42 honey samples collected during the three years yielded 80 pollen taxa/types: 72 dicotyledonous and 8 monocotyledonous, encompassing 41 botanical families spread into seven life forms namely, trees, shrubs, epiphytes, herbs, climbers, grasses, and sedges. Our results showed that pollen spectra were equally comparable between Locations and between Months and Years; the importance of this result is that it helped to demonstrate the complexity of ecological/environmental phenomena involved in the process of foraging by bees in a heterogeneous and complex landscape.     

Influence of Manganese and Zinc on Biochemical Profiles of Selected Algal Species: A Laboratory Study

The present study focused on the responses of six freshwater algal species (Anabaena ambigua, Anabaena subcylindrica, Nostoc commune, Nostoc muscorum, Spirogyra sp., and Spirulina sp.) to manganese and zinc. Laboratory experiments were conducted for the assessment of biochemical responses to manganese and zinc at various concentrations (0.1, 0.5, 1.0, 2.0, 3.0, 4.0, and 5.0 mg/L) for 15 days of exposure. After the incubation period, 10 ml of sample was centrifuged at 6000 rpm for 15 min and the pellets were used for measurement of the various experimental parameters. The toxicological study of manganese on algae showed that Anabaena ambigua was most sensitive algae. Regarding effects of manganese concentrations, chlorophyll, protein, carbohydrate, starch, and amino acid were inhibited 50% (IC₅₀) at 3 mg/L, whereas the toxicological study of zinc on algae Anabaena subcylindrica showed most adverse effects. Regarding effects of zinc concentrations, chlorophyll, protein, carbohydrate, starch, and amino acid were inhibited 50% (IC₅₀) at 1 mg/L. The inhibitory and stimulatory effects of either of the used heavy metals depend on concentration. Different organisms, however, have different sensitivities to the same metal, and the same organism may be more or less damaged by different metals.     

Comprehensive quantitative lipidomic approach to investigate serum phospholipid alterations in breast cancer

Introduction

Globally, breast cancer is the most common cancer in women and ranks second most common cause of cancer related mortality. Although efforts are made by researchers in molecular characterization of breast cancer using “-OMIC’S” approaches, limited work has explored to understand the phospholipid alterations in breast cancer.

Objectives

This study aims to explore five classes of serum phospholipid alterations in breast cancer towards discrimination of breast cancer from benign and healthy controls.

Methods

Twenty eight each of breast cancer patients and age-matched benign and healthy control serum samples were used to identify alterations of phospholipids using liquid chromatography-multiple reaction monitoring-mass spectrometry. Both multivariate and univariate statistical analyses were applied to investigate breast cancer associated phospholipid alterations. Differentially expressed phospholipid species were further confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Results

Among the identified and quantified 200 phospholipids, 25 phospholipids were found to be statistically significant (VIP > 1.4 and ANOVA p < 0.05) in the serum of women with breast cancer when compared with benign and healthy controls. Comparison of serum phospholipids of breast cancer patients and healthy controls revealed 12 phospholipids were found to be differentially expressed in which six were up-regulated and six were down-regulated. While comparative analysis of breast cancer serum against benign showed an increased concentration of six phospholipids in breast cancer samples. Further, significantly altered phospholipids were structurally characterized by enhanced product ion scanning.

Conclusion

Our results demonstrate that some of the differentially regulated phospholipids identified in our study such as PE (14:1/16:0), PC (18:0/18:0), LPE 14:0, PE (20:0/22:2) could be a panel of potential signature which can discriminate breast cancer from benign and healthy controls. These findings also provide insight into lipidomic information that can be used for monitoring of breast cancer progression.

     

Induction of apoptosis‐like cell death and clearance of stress‐induced intracellular protein aggregates: dual roles for Ustilago maydis metacaspase Mca1

Metacaspases primarily associate with induction and execution of programmed cell death in protozoa, fungi and plants. In the recent past, several studies have also demonstrated cellular functions of metacaspases other than cell death in different organisms including yeast and protozoa. This study shows similar dual function for the only metacaspase of a biotrophic phytopathogen, Ustilago maydis. In addition to a conventional role in the induction of cell death, Mca1 has been demonstrated to play a key role in maintaining the quality of the cellular proteome. On one hand, Mca1 could be shown to bring about apoptosis‐like phenotypic changes in U. maydis on exposure to oxidative stress, on the other hand, the protein was found to regulate cellular protein quality control. U. maydis metacaspase has been found to remain closely associated with the insoluble intracellular protein aggregates, generated during an event of stress exposure to the fungus. The study, therefore, provides direct evidence for a role of U. maydis metacaspase in the clearance of the stress‐induced intracellular insoluble protein aggregates. Furthermore, host infection assays with mca1 deletion strain also revealed a role of the protein in the virulence of the fungus.     

Allele exchange at the EPSPS locus confers glyphosate tolerance in cassava

Effective weed control can protect yields of cassava (Manihot esculenta) storage roots. Farmers could benefit from using herbicide with a tolerant cultivar. We applied traditional transgenesis and gene editing to generate robust glyphosate tolerance in cassava. By comparing promoters regulating expression of transformed 5‐enolpyruvylshikimate‐3‐phosphate synthase (EPSPS) genes with various paired amino acid substitutions, we found that strong constitutive expression is required to achieve glyphosate tolerance during in vitro selection and in whole cassava plants. Using strategies that exploit homologous recombination (HR) and nonhomologous end‐joining (NHEJ) DNA repair pathways, we precisely introduced the best‐performing allele into the cassava genome, simultaneously creating a promoter swap and dual amino acid substitutions at the endogenous EPSPS locus. Primary EPSPS‐edited plants were phenotypically normal, tolerant to high doses of glyphosate, with some free of detectable T‐DNA integrations. Our methods demonstrate an editing strategy for creating glyphosate tolerance in crop plants and demonstrate the potential of gene editing for further improvement of cassava.