Captopril mitigates splenomegaly and myelofibrosis in the Gata1low murine model of myelofibrosis

Allogeneic stem cell transplantation is currently the only curative therapy for primary myelofibrosis (MF), while the JAK2 inhibitor, ruxolitinib. Has been approved only for palliation. Other therapies are desperately needed to reverse life‐threatening MF. However, the cell(s) and cytokine(s) that promote MF remain unclear. Several reports have demonstrated that captopril, an inhibitor of angiotensin‐converting enzyme that blocks the production of angiotensin II (Ang II), mitigates fibrosis in heart, lung, skin and kidney. Here, we show that captopril can mitigate the development of MF in the Gata1^low mouse model of primary MF. Gata1^low mice were treated with 79 mg/kg/d captopril in the drinking water from 10 to 12 months of age. At 13 months of age, bone marrows were examined for fibrosis, megakaryocytosis and collagen expression; spleens were examined for megakaryocytosis, splenomegaly and collagen expression. Treatment of Gata1^low mice with captopril in the drinking water was associated with normalization of the bone marrow cellularity; reduced reticulin fibres, splenomegaly and megakaryocytosis; and decreased collagen expression. Our findings suggest that treating with the ACE inhibitors captopril has a significant benefit in overcoming pathological changes associated with MF.     

RCY1, an Arabidopsis thaliana RPP8/HRT family resistance gene,conferring resistance to cucumber mosaic virus requires salicylic acid,ethylene and a novel signal transduction mechanism

The dominant locus, RCY1, in the Arabidopsis thaliana ecotype C24 confers resistance to the yellow strain of cucumber mosaic virus (CMV-Y). The RCY1 locus was mapped to a 150-kb region on chromosome 5. Sequence comparison of this region from C24 and a CMV-Y-susceptible C24 mutant predicts that the RCY1 gene encodes a 104-kDa CC-NBS-LRR-type protein. The RCY1 gene from C24, when expressed in the susceptible ecotype Wassilewskija (Ws), restricted the systemic spread of virus. RCY1 is allelic to the resistance genes RPP8 from the ecotype Landsberg erecta and HRT from the ecotype Dijon-17, which confer resistance to Peronospora parasitica biotype Emco5 and turnip crinkle virus (TCV), respectively. Examination of RCY1 plants defective in salicylic acid (SA), jasmonic acid (JA) and ethylene signaling revealed a requirement for SA and ethylene signaling in mounting a resistance response to CMV-Y. The RCY1 nahG etr1 double mutants exhibited an intermediate level of susceptibility to CMV-Y, compared to the resistant ecotype C24 and the susceptible ecotypes Columbia and Nossen. This suggests that in addition to SA and ethylene, a novel signaling mechanism is associated with the induction of resistance in CMV-Y-infected C24 plants. Moreover, our results suggest that the signaling pathways downstream of the RPP8, HRT, and RCY1 have evolved independently.     

Opposing effects of MYZUS PERSICAE‐INDUCED LIPASE 1 and jasmonic acid influence the outcome of Arabidopsis thaliana–Fusarium graminearum interaction

Fusarium graminearum (Fg) is an important fungal pathogen of small grain cereals that can also infect Arabidopsis thaliana. In Arabidopsis, jasmonic acid (JA) signalling involving JASMONATE RESISTANT 1 (JAR1), which synthesizes JA‐isoleucine, a signalling form of JA, promotes susceptibility to Fg. Here we show that Arabidopsis MYZUS PERSICAE‐INDUCED LIPASE 1 (MPL1), via its influence on limiting JA accumulation, restricts Fg infection. MPL1 expression was up‐regulated in response to Fg infection, and MPL1‐OE plants, which overexpress MPL1, exhibited enhanced resistance against Fg. In comparison, disease severity was higher on the mpl1 mutant than the wild type. JA content was lower in MPL1‐OE and higher in mpl1 than in the wild type, indicating that MPL1 limits JA accumulation. Pharmacological experiments confirmed the importance of MPL1‐determined restriction of JA accumulation on curtailment of Fg infection. Methyl‐JA application attenuated the MPL1‐OE‐conferred resistance, while the JA biosynthesis inhibitor ibuprofen enhanced resistance in mpl1. Also, the JA biosynthesis‐defective opr3 mutant was epistatic to mpl1, resulting in enhanced resistance in mpl1 opr3 plants. In comparison, JAR1 was not essential for the mpl1‐conferred susceptibility to Fg. Considering that methyl‐JA promotes Fg growth in culture, we suggest that in part MPL1 curtails disease by limiting the availability of a plant‐derived Fg growth‐promoting factor.     

In vitro anticancer properties of selected <Emphasis Type="Italic">Eucalyptus</Emphasis> species

In spite of the recent advancements in oncology, the overall survival rate for pancreatic cancer has not improved over the last five decades. Eucalypts have been linked with cytotoxic and anticancer properties in various studies; however, there is very little scientific evidence that supports the direct role of eucalypts in the treatment of pancreatic cancer. This study assessed the anticancer properties of aqueous and ethanolic extracts of four Eucalyptus species using an MTT assay. The most promising extracts were further evaluated using a CCK-8 assay. Apoptotic studies were performed using a caspase 3/7 assay in MIA PaCa-2 cells. The aqueous extract of Eucalyptus microcorys leaf and the ethanolic extract of Eucalyptus microcorys fruit inhibited the growth of glioblastoma, neuroblastoma, lung and pancreatic cancer cells by more than 80% at 100 μg/mL. The E. microcorys and Eucalyptus saligna extracts showed lower GI₅₀ values than the ethanolic Eucalyptus robusta extract in MIA PaCa-2 cells. Aqueous E. microcorys leaf and fruit extracts at 100 μg/mL exerted significantly higher cell growth inhibition in MIA PaCa-2 cells than other extracts (p < 0.05). Statistically similar IC₅₀ values (p > 0.05) were observed in aqueous E. microcorys leaf (86.05 ± 4.75 μg/mL) and fruit (64.66 ± 15.97 μg/mL) and ethanolic E. microcorys leaf (79.30 ± 29.45 μg/mL) extracts in MIA PaCa-2 cells using the CCK-8 assay. Caspase 3/7-mediated apoptosis and morphological changes of cells were also witnessed in MIA PaCa-2 cells after 24 h of treatment with the extracts. This study highlighted the significance of E. microcorys as an important source of phytochemicals with efficacy against pancreatic cancer cells. Further studies are warranted to purify and structurally identify individual compounds and elucidate their mechanisms of action for the development of more potent and specific chemotherapeutic agents for pancreatic cancer.     

Store operated Ca2+ entry dependent contraction of coronary artery smooth muscle: inhibition by peroxide pretreatment

The sarco/endoplasmic reticulum (SER) Ca(2+) pool is refilled by the SER Ca(2+) pump (SERCA) using cytosolic Ca(2+) and/or extracellular Ca(2+) entering the cell. The effects of the SERCA pump inhibitor cyclopiazonic acid (CPA) were studied in pig coronary artery smooth muscle using two protocols. In protocol A, the SERCA pump was inhibited by adding CPA to cells/tissues in Ca(2+)-containing solution, whereas in protocol B, CPA was added to cells/tissues in Ca(2+)-free solution, followed by reintroduction of extracellular Ca(2+). Addition of CPA increased cytosolic Ca(2+) in cultured smooth muscle cells and elicited contraction in de-endothelialized coronary arteries in both protocols. Based on pharmacological experiments, the CPA-induced contraction of de-endothelialized arteries in protocol B resulted from store operated Ca(2+) entry (SOCE). Reactive oxygen species such as peroxides are known to damage the SERCA pump in this tissue. Consistently, CPA-induced contractions were decreased in arteries pre-treated with hydrogen peroxide in protocol A. However, this pretreatment also decreased the force of contraction due to SOCE in protocol B, suggesting that it closed SOCE. We propose that the closure of SOCE triggered by exposure to reactive oxygen species may be a protective mechanism, so that Ca(2+) entry by this pathway is disallowed when SERCA is damaged in pathologies such as ischemia-reperfusion.     

Activities of sucrolytic enzymes in developing pods of lentil genotypes differing in seed size

The activities of sucrolytic enzymes viz. sucrose synthase and invertases were compared in developing pods of two genotypes of lentil differing in seed weight. Biomass accumulation of both the podwall and seed of ‘large’ genotype was higher during development as compared to the ‘small’ genotype. High activity of acid invertase together with prolonged activity of alkaline invertase in podwall of ‘large’ genotype may lead to longer cell division phase resulting in its larger size and biomass. Greater biomass of podwall could be responsible for providing more reserves for the developing seed hence determining its size. Higher alkaline invertase activity in ‘large’ seed from 15–20 DAF can be correlated to the sustained sucrolytic conditions for producing more cells required for its larger size. Increased levels of sucrose synthase in ‘large’ seed especially during maturation phase suggest the role of this enzyme in enhancing the seed sink strength.     

Selection of salt tolerant plants of Nicotiana tabacum L. through in vitro and its biochemical characterization

Sodium chloride tolerant organogenic callus lines of Nicotiana tabacum were developed in vitro on Murashige and Skoog [16] medium supplemented with BA, IAA and different concentration of NaCl. The maximum shoot bud regeneration was achieved from both tolerant and non-tolerant calluses on MS medium supplemented with 1.0 mg/l BA, 0.1 mg/l IAA with or without NaCl within 4 weeks of culture. Standard growth parameters such as fresh weight and dry weight of organogenic callus, growth tolerant index and enzyme activity (peroxidase and catalase) were used as indicators of salt tolerance. The growth tolerance index in the 4-week after the beginning of treatments yielded significant differences among the non-tolerant and tolerant organogenic callus lines. The regenerated shoots were rooted on half-strength MS basal salts supplemented with 2% sucrose but devoid of growth regulator. The regenerated plants from tolerant callus lines were capable of growing in vitro in presence of 175 mM NaCl. SDS-PAGE profile showed that the progenies derived from tolerant sources were tolerant to salt. This investigation may help in the selection and characterization of salt tolerance in plant improvement programme.