Ectopic expression of C 4 photosynthetic pathway genes improves carbon assimilation and alleviate stress tolerance for future climate change

Alteration in atmospheric carbon dioxide concentration and other environmental factors are the significant cues of global climate change. Environmental factors affect the most fundamental biological process including photosynthesis and different metabolic pathways. The feeding of the rapidly growing world population is another challenge which imposes pressure to improve productivity and quality of the existing crops. C4 plants are considered the most productive, containing lower photorespiration, and higher water-use & N-assimilation efficiencies, compared to C3 plants. Besides, the C4-photosynthetic genes not only play an important role in carbon assimilation but also modulate abiotic stresses. In this review, fundamental three metabolic processes (C4, C3, and CAM) of carbon dioxide assimilation, the evolution of C4-photosynthetic genes, effect of elevated CO2 on photosynthesis, and overexpression of C4-photosynthetic genes for higher photosynthesis were discussed. Kranz-anatomy is considered an essential prerequisite for the terrestrial C4 carbon assimilation, but single-celled C4 plant species changed this well-established paradigm. C4 plants are insensitive to an elevated CO2 stress condition but performed better under stress conditions. Overexpression of essential C4-photosynthetic genes such as PEPC, PPDK, and NADP-ME in C3 plants like Arabidopsis, tobacco, rice, wheat, and potato not only improved photosynthesis but also provided tolerance to various environmental stresses, especially drought. The review provides useful information for sustainable productivity and yield under elevated CO2 environment, which to be explored further for CO2 assimilation and also abiotic stress tolerance. Additionally, it provides a better understanding to explore C4-photosynthetic gene(s) to cope with global warming and prospective adverse climatic changes.     

Recovery of <Emphasis Type="Italic">Bacillus</Emphasis> and <Emphasis Type="Italic">Pseudomonas</Emphasis> spp. from the ‘Fired Plots’ Under Shifting Cultivation in Northeast India

Soil samples, collected after the fire operations at agricultural sites under shifting cultivation in northeast India, were subjected to physico-chemical and microbial analysis. The fire affected various physico-chemical properties of the soil. Significant differences in pH and electrical conductivity were recorded in soil of fired and fallow plots. Significantly higher amounts of total organic carbon and nitrogen were estimated in fallow plots as compared to the fired. Difference in total phosphates was not significant. The fire operations resulted in stimulation of microbial communities. The bacteria were the most affected group followed by actinomycetes and fungi, respectively. The bacterial and actinomycetes counts were significantly higher in fired plots as compared to the fallow plots. The representative bacterial species recovered from the ‘fired plots’ belonged to the genus Bacillus and Pseudomonas. 16S rRNA analysis revealed their maximum similarity with B. clausii, B. licheniformis, B. megaterium, B. subtilis, B. thuringiensis, P. aeruginosa and P. stutzeri. Most of these species were found to be positive for phosphate solubilization and antagonism in plate based assays. In view of the importance of Bacillus and Pseudomonas species in plant growth promotion and biocontrol, recovery of these species after fire operations is indicative of the microbiological merit of shifting cultivation.     

Effects of Nickel Supplementation on Antioxidant Status,Immune Characteristics,and Energy and Lipid Metabolism in Growing Cattle

Biological Trace Element Research - Nickel and chromium existing in stainless-steel crowns (SSCs, used in pediatric dentistry) might be cytotoxic and allergenic. However, no in vivo studies have...     

A review on emulsion liquid membrane (ELM) for the treatment of various industrial effluent streams

Reviews in Environmental Science and Bio/Technology - The excessive release of toxic metal ions by the several industrial effluent streams into the environment has imposed a serious threat to the...     

Ectopic over-expression of peroxisomal ascorbate peroxidase (SbpAPX) gene confers salt stress tolerance in transgenic peanut (Arachis hypogaea)

Peroxisomal ascorbate peroxidase gene (SbpAPX) of an extreme halophyte Salicornia brachiata imparts abiotic stress endurance and plays a key role in the protection against oxidative stress. The cloned SbpAPX gene was transformed to local variety of peanut and about 100 transgenic plants were developed using optimized in vitro regeneration and Agrobacterium mediated genetic transformation method. The T₀ transgenic plants were confirmed for the gene integration; grown under controlled condition in containment green house facility; seeds were harvested and T₁ plants were raised. Transgenic plants (T₁) were further confirmed by PCR using gene specific primers and histochemical GUS assay. About 40 transgenic plants (T₁) were selected randomly and subjected for salt stress tolerance study. Transgenic plants remained green however non-transgenic plants showed bleaching and yellowish leaves under salt stress conditions. Under stress condition, transgenic plants continued normal growth and completed their life cycle. Transgenic peanut plants exhibited adequate tolerance under salt stress condition and thus could be explored for the cultivation in salt affected areas for the sustainable agriculture.     

Maximizing Peptide Identification Events in Proteomic Workflows Using Data-Dependent Acquisition (DDA)

Current analytical strategies for collecting proteomic data using data-dependent acquisition (DDA) are limited by the low analytical reproducibility of the method. Proteomic discovery efforts that exploit the benefits of DDA, such as providing peptide sequence information, but that enable improved analytical reproducibility, represent an ideal scenario for maximizing measureable peptide identifications in “shotgun”-type proteomic studies. Therefore, we propose an analytical workflow combining DDA with retention time aligned extracted ion chromatogram (XIC) areas obtained from high mass accuracy MS1 data acquired in parallel. We applied this workflow to the analyses of sample matrixes prepared from mouse blood plasma and brain tissues and observed increases in peptide detection of up to 30.5% due to the comparison of peptide MS1 XIC areas following retention time alignment of co-identified peptides. Furthermore, we show that the approach is quantitative using peptide standards diluted into a complex matrix. These data revealed that peptide MS1 XIC areas provide linear response of over three orders of magnitude down to low femtomole (fmol) levels. These findings argue that augmenting “shotgun” proteomic workflows with retention time alignment of peptide identifications and comparative analyses of corresponding peptide MS1 XIC areas improve the analytical performance of global proteomic discovery methods using DDA.Label-free methods in mass spectrometry-based proteomics, such as those used in common “shotgun” proteomic studies, provide peptide sequence information as well as relative measurements of peptide abundance (1–3). A common data acquisition strategy is based on data-dependent acquisition (DDA)¹ where the most abundant precursor ions are selected for tandem mass spectrometry (MS/MS) analysis (1–2). DDA attempts to minimize redundant peptide precursor selection and maximize the depth of proteome coverage (2). However, the analytical reproducibility of peptide identifications obtained using DDA-based methods result in <75% overlap between technical replicates (3–4). Comparisons of peptide identifications between replicate analyses have shown that the rate of new peptide identifications increases sharply following two replicate sample injections and gradually tapers off after approximately five replicate injections (4). This phenomenon is due, in part, to the semirandom sampling of peptides in a DDA experiment (5).Alternate label-free methods focused on measuring the abundance of intact peptide ions, such as the accurate mass and time tag (AMT) approach (6–8, 42), are aimed at differential analyses of extracted ion chromatogram (XIC) areas integrated from high mass accuracy peptide precursor mass spectra (MS1 spectra) exhibiting discrete chromatographic elution times. This method is particularly powerful for the analysis of post-translationally modified (PTM) peptides as pairing the low abundance of PTM candidates with the variable nature of DDA complicates comparisons between samples (9, 43). However, label-free strategies focused on the analysis of peptide MS1 XIC areas are dependent on a priori knowledge of peptide ions and retention times (2–10). Thus, prospective analyses of samples are needed to assess peptides and their respective retention times. This prospective analysis may not be possible for reagent-limited samples. Further, the usage of previously established peptide features in the analysis of different sample types can be confounded by unknown matrix effects that can produce variable retention time characteristics and peptide ion suppression (2). Therefore, proteomic strategies that make use of DDA, to provide peptide sequence information and identify features within the sample, but that also use MS1 data for comparisons between samples, represent an ideal combination for maximizing measureable peptide identification events in “shotgun” proteomic discovery analyses.Here we describe an analytical workflow that combines traditional DDA methods with the analysis of retention time aligned XIC areas extracted from high mass accuracy peptide precursor MS1 spectra. This method resulted in a 25.1% (±6.6%) increase in measureable peptide identification events across samples of diverse composition because of the inferential extraction of peptide MS1 XIC areas in sample sets lacking corresponding MS/MS events. These findings were observed in measurements of peptide MS1 XIC abundances using sample types ranging from tryptic digests of olfactory bulb tissues dissected from Homer2 knockout and wild-type mice to mouse blood plasma exhibiting differential levels of hemolysis. We further establish that this method is quantitative using a dilution series of known bovine standard peptide concentrations spiked into mouse blood plasma. These data show that comparative analysis between samples should be performed using peptide MS1 data as opposed to semirandomly sampled peptide MS/MS data. This approach maximizes the number of peptides that can be compared between samples.     

The SbMT-2 Gene from a Halophyte Confers Abiotic Stress Tolerance and Modulates ROS Scavenging in Transgenic Tobacco

Heavy metals are common pollutants of the coastal saline area and Salicornia brachiata an extreme halophyte is frequently exposed to various abiotic stresses including heavy metals. The SbMT-2 gene was cloned and transformed to tobacco for the functional validation. Transgenic tobacco lines (L2, L4, L6 and L13) showed significantly enhanced salt (NaCl), osmotic (PEG) and metals (Zn⁺⁺, Cu⁺⁺ and Cd⁺⁺) tolerance compared to WT plants. Transgenic lines did not show any morphological variation and had enhanced growth parameters viz. shoot length, root length, fresh weight and dry weight. High seed germination percentage, chlorophyll content, relative water content, electrolytic leakage and membrane stability index confirmed that transgenic lines performed better under salt (NaCl), osmotic (PEG) and metals (Zn⁺⁺, Cu⁺⁺ and Cd⁺⁺) stress conditions compared to WT plants. Proline, H₂O₂ and lipid peroxidation (MDA) analyses suggested the role of SbMT-2 in cellular homeostasis and H₂O₂ detoxification. Furthermore in vivo localization of H₂O₂ and O₂ ⁻; and elevated expression of key antioxidant enzyme encoding genes, SOD, POD and APX evident the possible role of SbMT-2 in ROS scavenging/detoxification mechanism. Transgenic lines showed accumulation of Cu⁺⁺ and Cd⁺⁺ in root while Zn⁺⁺ in stem under stress condition. Under control (unstressed) condition, Zn⁺⁺ was accumulated more in root but accumulation of Zn⁺⁺ in stem under stress condition suggested that SbMT-2 may involve in the selective translocation of Zn⁺⁺ from root to stem. This observation was further supported by the up-regulation of zinc transporter encoding genes NtZIP1 and NtHMA-A under metal ion stress condition. The study suggested that SbMT-2 modulates ROS scavenging and is a potential candidate to be used for phytoremediation and imparting stress tolerance.     

How Many People Living with HIV Will Be Additionally Eligible for Antiretroviral Treatment in Karnataka State,India as per the World Health Organization 2013 Guidelines?

Background

The National AIDS control programme (NACP) in India is currently following the World Health Organization (WHO) 2010 antiretroviral therapy (ART) guidelines. In 2013, the WHO revised its recommendations for initiating ART among people living with HIV (PLHIV) by increasing the threshold for ART initiation to a CD4 count ≤500 cells/uL. For certain patient groups, ART is recommended irrespective of CD4 count (PLHIV with active tuberculosis, hepatitis B virus infection, pregnant and breast feeding women, children aged under five years and those living in a sero-discordant relationship). In this operational research, we assess the effect of applying this recommendation on the number of PLHIV additionally eligible for ART.

Methods

This was a cross-sectional analysis of routinely collected programme data from all PLHIV registered in Karnataka State (population 60 million), India in 2012.

Results

Of 37,044 PLHIV, 27,074 (73%) were eligible for initiating ART as per WHO-2010 criteria. As per the WHO-2013 criteria (CD4 count ≤500 and all pregnant women and under-five children irrespective of CD4 count), an additional 5104 (14%) HIV-infected people would be eligible for initiating ART. There were no data to inform the additional patient load due to sero-discordance.

Conclusion

Adopting the WHO-2013 guidelines for India has important resource implications. However, given the significant patient and programmatic benefits of adopting the new guidelines, this has been considered favourably by the NACP in India and steps are being planned to integrate ART care into the general health system to cope with the increased numbers of patients.