Soil salinity is one of the abiotic constraints that imbalance nutrient acquisition, hampers plant growth, and leads to potential loss in agricultural productivity. Salt-tolerant plant growth-promoting rhizobacteria (PGPR) can alleviate the adverse impacts of salt stress by mediating molecular, biochemical, and physiological status. In the present study, the bacterium Bacillus mycoides PM35 showed resistance up to 3 M NaCl stress and exhibited plant growth-promoting features. Under salinity stress, the halo-tolerant bacterium B. mycoides PM35 showed significant plant growth-promoting traits, such as the production of indole acetic acid, siderophore, ACC deaminase, and exopolysaccharides. Inoculation of B. mycoides PM35 alleviated salt stress in plants and enhanced shoot and root length under salinity stress (0, 300, 600, and 900 mM). The B. mycoides PM35 alleviated salinity stress by enhancing the photosynthetic pigments, carotenoids, radical scavenging capacity, soluble sugars, and protein content in inoculated maize plants compared to non-inoculated plants. In addition, B. mycoides PM35 significantly boosted antioxidant activities, relative water content, flavonoid, phenolic content, and osmolytes while reducing electrolyte leakage, H2O2, and MDA in maize compared to control plants. Genes conferring abiotic stress tolerance (CzcD, sfp, and srfAA genes) were amplified in B. mycoides PM35. Moreover, all reactions are accompanied by the upregulation of stress-related genes (APX and SOD). Our study reveals that B. mycoides PM35 is capable of promoting plant growth and increasing agricultural productivity.

Optical emission spectroscopy of the active species in N 2 plasma is carried out to investigate their concentration as a function of discharge parameters such as filling pressure (2.0-7.0 mbar), source power (100-200 W) and gas flow rate (50-300 mg/min). The primary motivation of this work is to obtain reliable information about the concentration of the active species of N 2 plasma, which play an important role in plasma surface nitriding processes. Emission intensity from the selected electronic excited states of molecular and atomic species is evaluated as a function of discharge parameters to investigate their concentration. The emission intensity ratio I (N + 2 )/I (N 2 ) and I (N + )/I (N ) of the electronic transitions is also evaluated as a function of discharge parameters to investigate the relative dependence of their concentrations. It is observed that the concentration of the active species of N 2 plasma is strongly affected by the filling pressure and source power whereas flow rate has no significant effect. An increased occurrence of N + 2 molecular ions in comparison with N 2 molecules, and N + ions in comparison with N atoms is observed with source power whereas decreased occurrence of N + 2 molecular ions in comparison with N 2 molecules, and N + ions in comparison with N atoms is observed with the rise in filling pressure.

The room temperature nitriding of titanium is accomplished by utilizing nitrogen ion beams delivered by a 2.3 kJ plasma focus discharge. Titanium samples are exposed to ions at different axial positions (3, 5, 7 and 9 cm from the focus) in order to correlate their surface properties with ion beam parameters such as energy, number density, current density and energy flux (energy deliverance per unit time per unit volume). A BPX65 photodiode detector is employed to measure the ion beam parameters by using the time of flight technique. X-ray diffraction analysis as well as field emission scanning electron microscopy along with the energy dispersive x-ray spectroscopy is carried out to explore the structural, morphological and compositional profiles of the treated samples. The results demonstrate the formation of nanocrystalline TiN thin film with surface features strongly dependent on ion beam energy flux. A Vickers microindentation measurement reveals that the surface hardness is improved 4–5 times for typical nitrided samples.

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Trace rare-gas–optical emission spectroscopy is carried out to characterize the nitrogen plasma as a function of discharge parameters. The functional dependence of N2(CΠu3) and N2+(BΣu+2) excited states is monitored by measuring the emission intensities of the bandheads of second positive and first negative systems. The excited-state population density of N atoms and N2 molecules, extracted from their optical emission, is related to the ground-state population density after normalizing the changes for excitation cross section and electron energy distribution function by optical actinometry. The electron temperature is determined from the plasma-induced optical emission of trace rare gas by the line-to-line method. The obtained data may help us to adjust the optimum discharge conditions for the production of active species, which are considered to be important for the desired treatment of the samples.

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BackgroundBCR-ABL kinase domain mutations are infrequently detected in newly diagnosed chronic-phase chronic myeloid leukemia (CML) patients. Recent studies indicate the presence of pre-existing BCR-ABL mutations in a higher percentage of CML patients when CD34+ stem/progenitor cells are investigated using sensitive techniques, and these mutations are associated with imatinib resistance and disease progression. However, such studies were limited to smaller number of patients.MethodsWe investigated BCR-ABL kinase domain mutations in CD34+ cells from 100 chronic-phase CML patients by multiplex allele-specific PCR and sequencing at diagnosis. Mutations were re-investigated upon manifestation of imatinib resistance using allele-specific PCR and direct sequencing of BCR-ABL kinase domain.ResultsPre-existing BCR-ABL mutations were detected in 32/100 patients and included F311L, M351T, and T315I. After a median follow-up of 30 months (range 8–48), all patients with pre-existing BCR-ABL mutations exhibited imatinib resistance. Of the 68 patients without pre-existing BCR-ABL mutations, 24 developed imatinib resistance; allele-specific PCR and BCR-ABL kinase domain sequencing detected mutations in 22 of these patients. All 32 patients with pre-existing BCR-ABL mutations had the same mutations after manifestation of imatinib-resistance. In imatinib-resistant patients without pre-existing BCR-ABL mutations, we detected F311L, M351T, Y253F, and T315I mutations. All imatinib-resistant patients except T315I and Y253F mutations responded to imatinib dose escalation.ConclusionPre-existing BCR-ABL mutations can be detected in a substantial number of chronic-phase CML patients by sensitive allele-specific PCR technique using CD34+ cells. These mutations are associated with imatinib resistance if affecting drug binding directly or indirectly. After the recent approval of nilotinib, dasatinib, bosutinib and ponatinib for treatment of chronic myeloid leukemia along with imatinib, all of which vary in their effectiveness against mutated BCR-ABL forms, detection of pre-existing BCR-ABL mutations can help in selection of appropriate first-line drug therapy. Thus, mutation testing using CD34+ cells may facilitate improved, patient-tailored treatment.

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