Leukemic priming of resting NK cells is killer Ig-like receptor independent but requires CD15-mediated CD2 ligation and natural cytotoxicity receptors

Resting human NK cells require a two-stage activation process that we have previously described as "priming" and "triggering." NK-sensitive tumor cells provide both priming and triggering signals. NK-resistant tumors evade lysis, mostly by failure to prime; however, we recently reported a tumor cell line (CTV-1) that primes resting NK cells but fails to trigger lysis. In this article, we report two additional leukemia cell lines that prime NK cells but are resistant to lysis. Tumor-mediated NK priming is via CD2 binding to a ligand within CD15 on the tumor cell. NK-resistant RAJI cells became susceptible to NK lysis following transfection and expression of CD15. Blockade of CD15 on K562 cells or on CD15(+) RAJI cells significantly inhibited lysis, as did blockade of CD2 on resting NK cells. NK priming via CD2 induced CD16 shedding, releasing CD3ζ to the CD2, leading to its phosphorylation and the subsequent phosphorylation of linker for activation of T cells and STAT-5 and synthesis of IFN-γ. Blockade of C-type lectin receptors significantly suppressed the tumor-mediated priming of NK cells, whereas blockade of Ig-superfamily-like receptors had no effect at the NK-priming stage. Tumor priming of resting NK cells was irrespective of HLA expression, and blockade of HLA-killer Ig-like receptor interactions did not influence the incidence or degree of priming. However, CD15-CD2 interactions were critical for NK priming and were required, even in the absence of HLA-mediated NK inhibition. Tumor-mediated priming led to a sustained primed state, and the activated NK cells retained the ability to lyse NK-resistant tumors, even after cryopreservation.     

The myth of plant transformation

Technology development is innovative to many aspects of basic and applied plant transgenic science. Plant genetic engineering has opened new avenues to modify crops, and provided new solutions to solve specific needs. Development of procedures in cell biology to regenerate plants from single cells or organized tissue, and the discovery of novel techniques to transfer genes to plant cells provided the prerequisite for the practical use of genetic engineering in crop modification and improvement. Plant transformation technology has become an adaptable platform for cultivar improvement as well as for studying gene function in plants. This success represents the climax of years of efforts in tissue culture improvement, in transformation techniques and in genetic engineering. Plant transformation vectors and methodologies have been improved to increase the efficiency of transformation and to achieve stable expression of transgenes in plants. This review provides a comprehensive discussion of important issues related to plant transformation as well as advances made in transformation techniques during three decades.     

Comparative role of animal manure and vegetable waste induced compost for polluted soil restoration and maize growth

Soil amendment with two types of composts: animal manure (AC) and vegetable waste (VC) induced composts have potential to alleviate Cd toxicity to maize in contaminated soil. Therefore, Cd mobility in waste water irrigated soil can be addressed through eco-friendly and cost effective organic soil amendments AC and VC that eventually reduces its translocation from polluted soil to maize plant tissues. The comparative effectiveness of AC and VC at 3% rate were evaluated on Cd solubility, its accumulation in maize tissues, translocation from root to shoot, chlorophyll contents, plant biomass, yield and soil properties (pH, NPK, OM). Results revealed that the addition of organic soil amendments significantly minimized Cd mobility and leachability in soil by 58.6% and 47%, respectively in VC-amended soil over control. While, the reduction was observed by 61.7% and 57%, respectively when AC was added at 3% over control. Comparing the control soil, Cd uptake effectively reduced via plants shoots and roots by 50%, 46% respectively when VC was added in polluted soil. However, Cd uptake was decreased in maize shoot and roots by 58% and 52.4% in AC amended soil at 3% rate, respectively. Additionally, NPK contents were significantly improved in polluted soil as well as in plant tissues in both composts amended soil Comparative to control, the addition of composts significantly improved the maize dry biomass and chlorophyll contents at 3% rate. Thus, present study confirmed that the addition of animal manure derived compost (AC) at 3% rate performed well and might be consider the suitable approach relative to vegetable compost for maize growth in polluted soil.     

Transgenic potato lines expressing hairpin RNAi construct of molting-associated EcR gene exhibit enhanced resistance against Colorado potato beetle (Leptinotarsa decemlineata,Say)

Transgenic Research - Most of the commercialized insect resistant transgenic crops express cry gene(s) isolated from Bacillus thuringiensis; however, intensive cultivation of Bt crops over almost...     

Isolation and characterization of a Serratia marcescens with insecticidal activity from Polyphylla olivieri (Col.: Scarabaeidae)

Members of the genus Serratia are known for their abilities to infect insects. In this study, a red‐pigmented S. marcescens was isolated and characterized from the infected larvae of Polyphylla olivieri using bacterial cultivation, phylogenetic analysis as well as bioassays against larvae of the two insect pests, Plodia interpunctella and Ephestia kuehniella. Comparative 16S rRNA and groEL gene sequence BLAST analyses strongly suggested that the isolated strain should be placed in the genus Serratia, sharing high sequence similarities with several strain of S. marcescens associated with insects. Phylogenetic analysis placed the isolated bacterium with other S. marcescens bacteria in a clade with high bootstrapping values. To assess pathogenicity of the S. marcescens isolate, the bacterial cells were either injected into the haemolymph of the fifth‐instar larvae or added to the diets of insects. Survival curves of the control insects and those challenged with six different concentrations of S. marcescens showed that the S. marcescens isolate significantly reduced survival rates of the larvae. The LC₅₀s of the bacterium on P. interpunctella and E. kuehniella were 1992.26 and 1.09 × 10⁴ (CFU/μl) for injection bioassays at 6 h post‐injection, and 4.48 × 10⁴ and 1.96 × 10⁵ (CFU/10 μl) for feeding bioassays at 24 h post‐feeding, respectively. Injection of the bacterial culture supernatant into the larvae led to continuous bleeding from the site of injection, while injection of heat‐treated culture supernatant of the bacterium did not cause continuous bleeding. Together, our results showed the possibility of using this S. marcescens isolate in microbial control of the insect pests after addressing the safety concerns. Moreover, it might be considered as a source of useful bioactive molecules and genes with application in insect control and biotechnology via developing insect‐resistant plants.     

Molecular Characterization of Whole Genomic RNA2 From Iranian Isolates of Grapevine Fanleaf Virus

Grapevine fanleaf virus (GFLV) is the major causal agent of the grapevine degeneration disease. To characterize the genomic RNA2 segment from Iranian isolates of GFLV, leaf samples were collected from infected vineyards in different locations with a long history of vine cultivation. Four isolates were selected for cloning and sequencing on the basis of the restriction profiles of RT‐PCR products. The sequencing data revealed that the RNA2 of the Iranian GFLV isolates were the shortest compared with that of all previously described GFLV isolates. The sizes were 3730 nucleotides (nt) for Shir‐Amin and Urmia isolates and 3749 nt for Takestan and Bonab isolates (excluding the poly (A) tail), due to deletion events in both 5′ and 3′ non‐coding regions. In the phylogenetic tree based on the full‐length nucleotide sequences of GFLV RNA2, all the GFLV isolates clustered into two groups with the exception of the Hungarian isolate (GHu). The Iranian isolates grouped as a distinct cluster. Recombination analyses showed that GFLV‐NW (Germany), GFLV‐F13 (reference isolate), GFLV isolate Shir‐Amin (Iran) and Arabis mosaic virus isolate Lv were recombinant isolates and one of their parents belonged to the same lineage as the Iranian isolates. These findings suggest that these isolates originated from a common ancestor.     

Targeted expression of insecticidal hybrid SN19 gene in potato leads to enhanced resistance against Colorado potato beetle (<Emphasis Type="Italic">Leptinotarsa decemlineata</Emphasis> Say) and tomato leafminer (<Emphasis Type="Italic">Tuta absoluta</Emphasis> Meyrick)

The expression of insecticidal genes must be induced at appropriate time and in sufficient amount to confer protection against targeted pests. However, the increased scientific reports of resistance development in insect pest against insecticidal delta-endotoxins, produced by Bacillus thuringiensis, provide impetus for the development of alternative insect management strategies. The present study was conducted to investigate the importance of targeted expression of a hybrid insecticidal gene (SN19) in potatoes. For this purpose, two plant expression vectors were constructed by cloning hybrid SN19 gene (cry1Ba-domain I–III and cry1Ia-domain II) under the control of a wound-inducible promoter isolated from Asparagus officinalis (AoPR1) and CaMV 35S promoter, and were transferred to Agrobacterium tumefaciens strain EHA 105. Four potato genotypes (Marabel, Innovator, Tokat 10/1 and Tokat 6/24) were transformed with EHA 105 strain harboring pTF101.1 35S–SN19 and pTF101.1 AoPR1–SN19 constructs. Phosphinothricin (PPT) was used at concentration of 1 mg/l for selection of primary transformants. PCR results showed the presence of both introduced SN19 and bar genes in 43 plants out of total 154 putative transgenics. Expression of SN19 protein in primary transformants was confirmed by Western blot assays. The mechanical wounding of transgenic plants exhibited more accumulated levels of SN19 proteins during post wounding period. Leaf biotoxicity assays with Colorado potato beetle (Coleoptera) and tomato leafminer (Lepidoptera) exhibited 100% mortality of the pests in primary transformants. Based on our mortality results with both constructs, we concluded that the potato transgenic lines exhibited targeted expression of insecticidal gene under the control of AoPR1 promoter upon insect wounding with eliminated toxicity of Cry protein and hence can be further used effectively in potato breeding programme.     

Efficiency of different types of biochars to mitigate Cd stress and growth of sunflower (Helianthus; L.) in wastewater irrigated agricultural soil

Cadmium contamination in croplands is recognized one of the major threat, seriously affecting soil health and sustainable agriculture around the globe. Cd mobility in wastewater irrigated soils can be curtailed through eco-friendly and cost effective organic soil amendments (biochars) that eventually minimizes its translocation from soil to plant. This study explored the possible effects of various types of plants straw biochar as soil amendments on cadmium (Cd) phytoavailability in wastewater degraded soil and its subsequent accumulation in sunflower tissues. The studied biochars including rice straw (RS), wheat straw (WS), acacia (AC) and sugarcane bagasse (SB) to wastewater irrigated soil containing Cd. Sunflower plant was grown as a test plant and Cd accumulation was recorded in its tissues, antioxidant enzymatic activity chlorophyll contents, plant biomass, yield and soil properties (pH, NPK, OM and Soluble Cd) were also examined. Results revealed that addition of biochar significantly minimized Cd mobility in soil by 53.4%, 44%, 41% and 36% when RS, WS, AC and SB were added at 2% over control. Comparing the control soil, biochar amended soil effectively reduced Cd uptake via plants shoots by 71.7%, 60.6%, 59% and 36.6%, when RS, WS, AC and SB. Among all the biochar, rice husk induced biochar significantly reduced oxidative stress and reduced SOD, POD and CAT activity by 49%, 40.5% and 46.5% respectively over control. In addition, NPK were significantly increased among all the added biochars in soil–plant system as well as improved chlorophyll contents relative to non-bioachar amended soil. Thus, among all the amendments, rice husk and wheat straw biochar performed well and might be considered the suitable approach for sunflower growth in polluted soil.