Airborne yeasts in Amritsar (India)

A survey of airborne yeasts in Amritsar has been carried out by the petri plate exposure method for a period of one year. A total of 14 yeasts species appeared on the plates. Candida was the commonest yeast representing 43.1% of the total colony count followed by Rhodotorula and Torulopsis. There was a seasonal variation in the concentration of the yeasts in the atmosphere. Maximal numbers were recorded in October and minima during January–February.     

Tamoxifen,protein kinase C and rat sperm mitochondria

Tamoxifen at a dose of 400 microg/kg/day has been reported to reduce the fertility of adult male rats and alter the pattern of cauda sperm motility from forward progressive to circular yawing type. Since sperm motility is powered by mitochondria, the effect of tamoxifen on mitochondrial function was studied. Tamoxifen treatment significantly increased rhodamine 123 fluorescent dye uptake by sperm mitochondria, reflecting an altered mitochondrial membrane potential. ATP and DAG levels, activities of glycolytic enzymes, creatine kinase and PKC all remained unaffected by tamoxifen. This is also the first report describing the presence of PKC alpha and beta in rat sperm. Morphological and biochemical integrity of sperm membranes was determined by electron microscopy and malondialdehyde levels, which were unaltered after tamoxifen treatment. This study indicates that the altered sperm motility induced by tamoxifen is accompanied by changes in mitochondrial membrane potential, but in the absence of any detectable change in membrane integrity, lipid peroxidation, ATP levels and activities of glycolytic enzymes, creatine kinase and PKC.     

Development and application of a method for analysis of lufenuron in wheat flour by gas chromatography-mass spectrometry and confirmation of bio-efficacy against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

A new analytical method using gas chromatography with mass spectrometry (GC-MS) for the quantitative determination of lufenuron, a benzoylphenylurea (BPU) class of insecticide, from wheat flour has been developed and applied for time-dependent residue monitoring in treated wheat flour. The analyte was extracted from wheat flour by a single step solid-liquid extraction by using ethyl acetate and subsequently cleaned up using the Primary Secondary Amine as a sorbent prior to GC-MS analysis. The present method provides sufficient sensitivity as reflected by the values of limit of detection (LOD) and limit of quantification (LOQ), 5 ng/mL (S/N approximately 3) and 50 ng/mL (the lowest validation point on the calibration curve), respectively. The calibration curve showed an excellent linearity in the concentration range of 50-1000 ng/mL (r2=0.998). The average recovery for spiked samples at three concentrations (150, 300, and 450 ng/g) was 98.23+/-2.52% R.S.D. The method was applied for the determination of lufenuron residues in treated wheat flour samples. Simultaneous determination of bio-efficacy of lufenuron residues was also carried out against the red flour beetle, Tribolium castaneum to correlate the actual residual effect of lufenuron as detected by the analytical method, over a period of 3 months. The findings revealed that the residual concentration of lufenuron were neither uniform nor in descending order over a period of 3 months in wheat flour, possibly because of an uneven dispersal in the treated wheat which was subsequently milled into flour, as confirmed by GC-MS analysis. However, the residues of lufenuron were sufficient to produce 100% mortality of T. castaneum larvae up to 3 months. The results have been discussed in view of the potential of lufenuron as a candidate molecule for the control of stored product pests.     

Concurrent modifications in the three homeologs of <Emphasis Type="Italic">Ms45</Emphasis> gene with CRISPR-Cas9 lead to rapid generation of male sterile bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Key message

Hexaploid bread wheat is not readily amenable to traditional mutagenesis approaches. In this study, we show efficient utilization of CRISPR-Cas system and Next Generation Sequencing for mutant analysis in wheat.

Abstract

Identification and manipulation of male fertility genes in hexaploid bread wheat is important for understanding the molecular basis of pollen development and to obtain novel sources of nuclear genetic male sterility (NGMS). The maize Male sterile 45 (Ms45) gene encodes a strictosidine synthase-like enzyme and has been shown to be required for male fertility. To investigate the role of Ms45 gene in wheat, mutations in the A, B and D homeologs were produced using CRISPR-Cas9. A variety of mutations in the three homeologs were recovered, including a plant from two different genotypes each with mutations in all three homeologs. Genetic analysis of the mutations demonstrated that all three wheat Ms45 homeologs contribute to male fertility and that triple homozygous mutants are required to abort pollen development and achieve male sterility. Further, it was demonstrated that a wild-type copy of Ms45 gene from rice was able to restore fertility to these wheat mutant plants. Taken together, these observations provide insights into the conservation of MS45 function in a polyploid species. Ms45 based NGMS can be potentially utilized for a Seed Production Technology (SPT)-like hybrid seed production system in wheat.