Selection of thermotolerant bradyrhizobial strains for nodulation of soybean (<Emphasis Type="Italic">Glycine max</Emphasis> L.) in semi-arid regions of Iran

Nodulation of soybeans grown in semi-arid region of southern parts of Iran is poor due to high air and soil temperatures. Here we identified thermotolerant isolates of soybean bradyrhizobia and evaluated the nitrogen fixation efficiency of the isolates under heat stress conditions in greenhouse and field experiments. The ability of fifty-six bradyrhizobial isolates to grow on solid or in liquid yeast extract mannitol medium at 38 and 41°C was evaluated. We identified 19 isolates, which were able to grow at 38°C and 10 isolates able to grow at 41°C. Greenhouse experiments were carried out at 28 and 38°C to study the nitrogen-fixing capacity of the isolates under optimal and high temperature conditions. Ten isolates had a symbiotic index of effectiveness of 80% or greater compared with nitrogen-fertilized treatments in greenhouse experiments at 28°C. Some thermotolerant isolates demonstrated good nitrogen-fixing performance at 38°C. Eight isolates were selected for use in a field trial in the natural high temperature environment of the Dezful region in Iran. Our results demonstrate that geographical origin can have a great influence on the successful selection of thermotolerant bradyrhizobia. Our thermotolerant isolates were mainly obtained from high-temperature regions, and improved shoot dry matter, nitrogen-uptake and seed yield of the plants.     

Neuropathological and genomic characterization of glioblastoma-induced rat model: How similar is it to humans for targeted therapy?

Glioblastoma multiforme (GBM) is a unique aggressive tumor and mostly develops in the brain, while rarely spreading out of the central nervous system. It is associated with a high mortality rate; despite tremendous efforts having been made for effective therapy, tumor recurrence occurs with high prevalence. To elucidate the mechanisms that lead to new drug discovery, animal models of tumor progression is one of the oldest and most beneficial approaches to not only investigating the aggressive nature of the tumor, but also improving preclinical research. It is also a useful tool for predicting novel therapies' effectiveness as well as side effects. However, there are concerns that must be considered, such as the heterogeneity of tumor, biological properties, pharma dynamic, and anatomic shapes of the models, which have to be similar to humans as much as possible. Although several methods and various species have been used for this approach, the real recapitulation of the human tumor has been left under discussion. The GBM model, which has been verified in this study, has been established by using the Rat C6 cell line. By exploiting bioinformatic tools, the similarities between aberrant gene expression and pathways have been predicted. In this regard, 610 common genes and a number of pathways have been detected. Moreover, while magnetic resonance imaging analysis enables us to compare tumor features between these two specious, pathological findings provides most of the human GBM characteristics. Therefore, the present study provides genomics, pathologic, and imaging evidence for showing the similarities between human and rat GBM models.     

Salinity Stress in Wheat: Effects,Mechanisms and Management Strategies

Salinity stress is a major threat to global food production and its intensity is continuously increasing because of anthropogenic activities. Wheat is a staple food and a source of carbohydrates and calories for the majority of people across the globe. However, wheat productivity is adversely affected by salt stress, which is associated with a reduction in germination, growth, altered reproductive behavior and enzymatic activity, disrupted photosynthesis, hormonal imbalance, oxidative stress, and yield reductions. Thus, a better understanding of wheat (plant) behavior to salinity stress has essential implications to devise counter and alleviation measures to cope with salt stress. Different approaches including the selection of suitable cultivars, conventional breeding, and molecular techniques can be used for facing salt stress tolerance. However, these techniques are tedious, costly, and labor-intensive. Management practices are still helpful to improve the wheat performance under salinity stress. Use of arbuscular mycorrhizal fungi, plant growth-promoting rhizobacteria, and exogenous application of phytohormones, seed priming, and nutrient management are important tools to improve wheat performance under salinity stress. In this paper, we discussed the effect of salinity stress on the wheat crop, possible mechanisms to deal with salinity stress, and management options to improve wheat performance under salinity conditions.     

Histo-morphological analysis of rice callus cultures reveals differential regeneration response with varying media combinations

Genetic transformation of most indica rice (Oryza sativa) cultivars is hampered by poor in vitro culture performance and low regeneration potential. Histological study of primary calli can provide substantial information on their regeneration potential and can be used for early grading of calli expected to develop plantlets on regeneration media. The study was aimed to undertake histological analysis of primary calli derived from mature seeds of five indica rice cultivars viz. KSK-133, KS-282, Shaheen Basmati, Super Basmati, and DilRosh in order to assess their regeneration potential on different media combinations supplemented with various hormone concentrations (N6 + 2 mg/L 2,4-Dichlorophenoxyacetic acid; N6 + 2 mg/L 2–4 D + 2 mg/L Benzylaminopurine and MS + 2 mg/L 2,4-D). Calli with regeneration capability were subjected to histological assays by examining toulidine blue stained 5–8 μm thin sections for the presence of meristematic zones exhibiting embryogenic callus features. Based on our observations, formation of embryoids or embryoid-like structures was pronounced in KSK-133 and KS-282 calli. However, DilRosh, Super Basmati and Shaheen Basmati did not show these characteristic features. Three-week-old calli of all rice cultivars were transferred into regeneration medium (MS + 2 mg/L BAP + 1 mg/L Naphthaleneacetic acid). KSK-133 and KS-282 showed the highest regeneration potential (81% and 76%, respectively). These data were supported by histological observations where characteristic embryogenic units (EU) were noticed in these genotypes. These meristematic regions displayed high mitotic activity and stained relatively dark. The embryogenic calli cells were found heavily cytoplasmic with prominent nuclei and were located on the callus surface or inside surrounded by parenchymal cells.

     

Isolation and functional analysis of cotton universal stress protein promoter in response to phytohormones and abiotic stresses

The 949 bp promoter fragment upstream from the translation initiation site of the GUSP gene encoding a universal stress protein was isolated from the genomic DNA of Gossypium arboreum. Some putative cis-acting elements involved in stress responses including E-box, ABRE, DPBF-box, and MYB-core elements were found in the promoter region. In an Agrobacterium-mediated transient expression assay, strong activation of the GUSP full promoter region occurred in tobacco leaves following dehydration, abscisic acid, salt, heavy metal, gibberellic acid and dark treatments. Deletion analysis of the promoter revealed that the dehydration, abscisic acid and salt responses were affected by the deletion between −208 and −949 bp and showed 2–4-fold induction. However, in response to dark, gibberellic acid and heavy metals the induction was only 2-fold. These findings further our understanding of the regulation of GUSP expression. This is an important study as no report of this universal stress protein promoter is available in literature.     

Proteomic and Phospho-Proteomic Profile of Human Platelets in Basal,Resting State: Insights into Integrin Signaling

During atherogenesis and vascular inflammation quiescent platelets are activated to increase the surface expression and ligand affinity of the integrin αIIbβ3 via inside-out signaling. Diverse signals such as thrombin, ADP and epinephrine transduce signals through their respective GPCRs to activate protein kinases that ultimately lead to the phosphorylation of the cytoplasmic tail of the integrin αIIbβ3 and augment its function. The signaling pathways that transmit signals from the GPCR to the cytosolic domain of the integrin are not well defined. In an effort to better understand these pathways, we employed a combination of proteomic profiling and computational analyses of isolated human platelets. We analyzed ten independent human samples and identified a total of 1507 unique proteins in platelets. This is the most comprehensive platelet proteome assembled to date and includes 190 membrane-associated and 262 phosphorylated proteins, which were identified via independent proteomic and phospho-proteomic profiling. We used this proteomic dataset to create a platelet protein-protein interaction (PPI) network and applied novel contextual information about the phosphorylation step to introduce limited directionality in the PPI graph. This newly developed contextual PPI network computationally recapitulated an integrin signaling pathway. Most importantly, our approach not only provided insights into the mechanism of integrin αIIbβ3 activation in resting platelets but also provides an improved model for analysis and discovery of PPI dynamics and signaling pathways in the future.     

Human embryonic stem cell-derived neural precursor transplants in collagen scaffolds promote recovery in injured rat spinal cord

Background aimsSeveral studies have reported functional improvement after transplantation of in vivo-derived neural progenitor cells (NPC) into injured spinal cord. However, the potential of human embryonic stem cell-derived NPC (hESC-NPC) as a tool for cell replacement of spinal cord injury (SCI) should be considered.MethodsWe report on the generation of NPC as neural-like tubes in adherent and feeder-free hESC using a defined media supplemented with growth factors, and their transplantation in collagen scaffolds in adult rats subjected to midline lateral hemisection SCI.ResultshESC-NPC were highly expressed molecular features of NPC such as Nestin, Sox1 and Pax6. Furthermore, these cells exhibited the multipotential characteristic of differentiating into neurons and glials in vitro. Implantation of xenografted hESC-NPC into the spinal cord with collagen scaffold improved the recovery of hindlimb locomotor function and sensory responses in an adult rat model of SCI. Analysis of transplanted cells showed migration toward the spinal cord and both neural and glial differentiation in vivo.ConclusionsThese findings show that transplantation of hESC-NPC in collagen scaffolds into an injured spinal cord may provide a new approach to SCI.     

High-throughput screening based identification of small molecule antagonists of integrin CD11b/CD18 ligand binding

Binding of leukocyte specific integrin CD11b/CD18 to its physiologic ligands is important for the development of normal immune response in vivo. Integrin CD11b/CD18 is also a key cellular effector of various inflammatory and autoimmune diseases. However, small molecules selectively inhibiting the function of integrin CD11b/CD18 are currently lacking. We used a newly described cell-based high-throughput screening assay to identify a number of highly potent antagonists of integrin CD11b/CD18 from chemical libraries containing >100,000 unique compounds. Computational analyses suggest that the identified compounds cluster into several different chemical classes. A number of the newly identified compounds blocked adhesion of wild-type mouse neutrophils to CD11b/CD18 ligand fibrinogen. Mapping the most active compounds against chemical fingerprints of known antagonists of related integrin CD11a/CD18 shows little structural similarity, suggesting that the newly identified compounds are novel and unique.     

Expression of <Emphasis Type="Italic">rol</Emphasis> genes in transgenic soybean (<Emphasis Type="Italic">Glycine max</Emphasis> L.) leads to changes in plant phenotype,leaf morphology,and flowering time

Soybean (Glycine max L.) cultivar NARC-4 was transformed with constructs carrying rolA, rolB, or rolC genes, each under the control of the Cauliflower Mosaic Virus 70S promoter. Cotyledonary nodes of soybean seeds were infected with Agrobacterium tumefaciens strain LBA4404 carrying one of the three rol genes, along with nptII in the plasmid pLBR. The efficiency of the transformation varied slightly among the three constructs, with frequencies of 6, 7, and 5% for the rolA, rolB, and rolC genes, respectively, being observed. Southern blot analysis confirmed the integration of rol genes in the soybean genome with varying numbers of copies of the transgene. All transformed plants showed enhanced rooting, but the number of adventitious roots was higher for transformants carrying the rolB transgene. rolA and rolC transformants showed dwarf phenotypes, clustered branching, and variations in leaf morphology. Furthermore, these plants flowered within a short period of time and produced lower numbers of flowers. rolB transformants showed variations in phenotype, including dwarf to semi-dwarf and shrubby growth, abnormal stem growth, short internodes, variations in leaf morphology, and greenish to yellowish-green colored leaves. These plants also flowered early, but dwarf plants produced low numbers of flowers, while shrubby plants produced high numbers of flowers, but these were mostly infertile.     

Usefulness of powdered and fresh egg yolk for cryopreservation of Zebu bull spermatozoa

This experiment was designed to compare powdered egg yolk with fresh egg yolk in an extender for cryopreservation of Zebu bull semen. Sperm motility, plasma membrane integrity and viability were assessed at different stages of cryopreservation (post-dilution, pre-freezing and post-thawing). Sperm plasma membrane integrity remained similar at all the stages of cryopreservation. Sperm motility and viability were significantly higher after thawing in the extender containing powdered egg yolk. In conclusion, powdered egg yolk may be used in an extender for the cryopreservation of Zebu bull spermatozoa.