The AAA+ ATPase TRIP13 remodels HORMA domains through N‐terminal engagement and unfolding

Proteins of the conserved HORMA domain family, including the spindle assembly checkpoint protein MAD2 and the meiotic HORMADs, assemble into signaling complexes by binding short peptides termed “closure motifs”. The AAA+ ATPase TRIP13 regulates both MAD2 and meiotic HORMADs by disassembling these HORMA domain–closure motif complexes, but its mechanisms of substrate recognition and remodeling are unknown. Here, we combine X‐ray crystallography and crosslinking mass spectrometry to outline how TRIP13 recognizes MAD2 with the help of the adapter protein p31^comet. We show that p31^comet binding to the TRIP13 N‐terminal domain positions the disordered MAD2 N‐terminus for engagement by the TRIP13 “pore loops”, which then unfold MAD2 in the presence of ATP. N‐terminal truncation of MAD2 renders it refractory to TRIP13 action in vitro, and in cells causes spindle assembly checkpoint defects consistent with loss of TRIP13 function. Similar truncation of HORMAD1 in mouse spermatocytes compromises its TRIP13‐mediated removal from meiotic chromosomes, highlighting a conserved mechanism for recognition and disassembly of HORMA domain–closure motif complexes by TRIP13.     

Tribal assignment of <Emphasis Type="Italic">Heldreichia</Emphasis> Boiss. (Brassicaceae): evidence from nuclear ITS and plastidic <Emphasis Type="Italic">ndh</Emphasis>F markers

Heldreichia Boiss. is a monospecific genus mainly distributed in Anatolia and the Lebanon. Although morphological variation and infrageneric phylogenetic relationships were recently studied in detail, Heldreichia remained as one of the few orphan genera that have not yet been assigned to any tribe. In the current study, we used sequence data from the nuclear ITS and chloroplast ndhF regions of Heldreichia and representatives of main Brassicaceae lineages and tribes to determine its tribal affiliation. Bayesian-based phylogenetic analyses clearly show with high support that Heldreichia is a member of the recently expanded tribe Biscutelleae. Furthermore, we characterize the tribe Biscutelleae morphologically and provide a determination key for all its genera.     

Folic acid reduces doxorubicin‐induced cardiomyopathy by modulating endothelial nitric oxide synthase

The use of doxorubicin (DOXO) as a chemotherapeutic drug has been hampered by cardiotoxicity leading to cardiomyopathy and heart failure. Folic acid (FA) is a modulator of endothelial nitric oxide (NO) synthase (eNOS), which in turn is an important player in diseases associated with NO insufficiency or NOS dysregulation, such as pressure overload and myocardial infarction. However, the role of FA in DOXO‐induced cardiomyopathy is poorly understood. The aim of this study was to test the hypothesis that FA prevents DOXO‐induced cardiomyopathy by modulating eNOS and mitochondrial structure and function. Male C57BL/6 mice were randomized to a single dose of DOXO (20 mg/kg intraperitoneal) or sham. FA supplementation (10 mg/day per oral) was started 7 days before DOXO injection and continued thereafter. DOXO resulted in 70% mortality after 10 days, with the surviving mice demonstrating a 30% reduction in stroke volume compared with sham groups. Pre‐treatment with FA reduced mortality to 45% and improved stroke volume (both P < 0.05 versus DOXO). These effects of FA were underlain by blunting of DOXO‐induced cardiomyocyte atrophy, apoptosis, interstitial fibrosis and impairment of mitochondrial function. Mechanistically, pre‐treatment with FA prevented DOXO‐induced increases in superoxide anion production by reducing the eNOS monomer:dimer ratio and eNOS S‐glutathionylation, and attenuated DOXO‐induced decreases in superoxide dismutase, eNOS phosphorylation and NO production. Enhancing eNOS function by restoring its coupling and subsequently reducing oxidative stress with FA may be a novel therapeutic approach to attenuate DOXO‐induced cardiomyopathy.     

The enigmatic meiotic dense body and its newly discovered component,SCML1, are dispensable for fertility and gametogenesis in mice

Meiosis is a critical phase in the life cycle of sexually reproducing organisms. Chromosome numbers are halved during meiosis, which requires meiosis-specific modification of chromosome behaviour. Furthermore, suppression of transposons is particularly important during meiosis to allow the transmission of undamaged genomic information between generations. Correspondingly, specialized genome defence mechanisms and nuclear structures characterize the germ line during meiosis. Survival of mammalian spermatocytes requires that the sex chromosomes form a distinct silenced chromatin domain, called the sex body. An enigmatic spherical DNA-negative structure, called the meiotic dense body, forms in association with the sex body. The dense body contains small non-coding RNAs including microRNAs and PIWI-associated RNAs. These observations gave rise to speculations that the dense body may be involved in sex body formation and or small non-coding RNA functions, e.g. the silencing of transposons. Nevertheless, the function of the dense body has remained mysterious because no protein essential for dense body formation has been reported yet. We discovered that the polycomb-related sex comb on midleg-like 1 (SCML1) is a meiosis-specific protein and is an essential component of the meiotic dense body. Despite abolished dense body formation, Scml1-deficient mice are fertile and proficient in sex body formation, transposon silencing and in timely progression through meiosis and gametogenesis. Thus, we conclude that dense body formation is not an essential component of the gametogenetic program in the mammalian germ line.     

Purification,Characterization, and Inhibition of Tyrosinase from Jerusalem Artichoke (Helianthus Tuberosus L.) Tuber

Background:Because it tends to cause deterioration in the quality of food and appearance, food browning is unacceptable. Tyrosinase, which catalyzes the transformation of mono phenolic compounds into o-quinones, has been associated with this phenomenon. Natural anti-browning agents were used to help avoid the enzymatic browning that occurs in many foods.Methods:Tyrosinase of Jerusalem Artichoke tubers was purified through (NH4)2SO4 sedimentation, dialysis, chromatography, and finally gel electrophoresis. The purified enzyme was characterized and inhibited by rosemary extracts.Results:Purification of tyrosinase from Jerusalem Artichoke tuber were accomplished. The specific activity at the final step of purification increased to 14115.76 U/mg protein with purification fold 32.89 using CM-Cellulose chromatography. The molecular mass was evaluated by electrophoresis and found to be 62 KDa. Maximum tyrosinase activity was found at 30 °C, pH 7.2, and higher affinity towards L-tyrosine. Inhibition percentage of heated extracts for leaves and flowers on tyrosinase activity was better than nonheated with 29.65% and 23.75%, respectively. The kinetic analysis exposed uncompetitive inhibition by leaves and flowers heated extracts. Conclusion:In this study, we concluded the usage of natural anti-browning inhibitors like rosemary extract be able to be castoff to substitute the chemical agents which might be dangerous to social healthiness. Natural anti-browning agents can be used to prevent the browning of many foods.Key Words: Jerusalem artichoke, Rosemary, Tyrosinase     

Long term outcome of severe anaemia in Malawian children

Background

Severe anaemia is a common, frequently fatal, condition in African children admitted to hospital, but its long term outcome is unknown. Early reports that survivors may be at risk of additional late morbidity and mortality may have significant implications for child survival in Africa. We assessed the short and long term outcome of severe anaemia in Malawian children and identified potential risk factors for death and further severe anaemia.

Methodology and Findings

For 18 months, we followed up children (6–60 months old) presenting to hospital with severe anaemia (haemoglobin ≤5g/dl) and their hospital and community controls with the aim to compare all cause mortality and severe anaemia recurrence rates between the groups, and to identify risk factors for these adverse outcomes. A total of 377 cases, 377 hospital controls and 380 community controls were recruited. Among cases, the in-hospital mortality was 6.4% and post-discharge all cause mortality was 12.6%, which was significantly greater than in hospital controls (2.9%) or community controls (1.4%) (Log rank test, p<0.001). The incidence of recurrence of severe anaemia among the cases was 0.102 per child-year (95% Confidence Interval 0.075–0.138), and was significantly higher than the 0.007 per child-year (95% CI 0.003–0.015) in the combined controls (p<0.0001). HIV was the most important risk factor both for post-discharge mortality (Hazard Ratio 10.5, 95% CI 4.0–27.2) and for recurrence of severe anaemia (HR 5.6, 95% CI 1.6–20.1).

Conclusions

Severe anaemia carries a high ‘hidden’ morbidity and mortality occurring in the months after initial diagnosis and treatment. Because severe anaemia is very common, this is likely to contribute importantly to overall under-five mortality. If not adequately addressed, severe anaemia may be an obstacle to achievement of the Millennium development goal No.4 on child survival. Strategies to diagnose and properly treat HIV infected children early most likely will reduce the high post-discharge mortality in severe anaemia.     

Nomenclatural novelties in miscellaneous Asian Brassicaceae (Cruciferae)

The new tribe Crucihimalayeae and three new genera Schrenkiella, Leiocarpaea and Ladakiella are described, and their diagnostic characters are discussed. Spirorhynchus is reduced to synonymy of Goldbachia, Ptilotrichum and Berteroella are merged with Stevenia, and Phaeonychium and Eurycarpus are merged with Solms‐laubachia. Thirteen new combinations are proposed: Goldbachia sabulosa (Kar. & Kir.) D. German & Al‐Shehbaz, Ladakiella klimesii (Al‐Shehbaz) D. German & Al‐Shehbaz, Leiocarpaea cochlearioides (Murr.) D. German & Al‐Shehbaz, Schrenkiella parvula (Schrenk) D. German & Al‐Shehbaz, Stevenia dahurica (Peschkova) D. German & Al‐Shehbaz, Stevenia maximowiczii (Palib.) D. German & Al‐Shehbaz, Solms‐laubachia albiflora (T. Anderson) D. German & Al‐Shehbaz, Solms‐laubachia kashgarica (Botsch.) D. German & Al‐Shehbaz, Solms‐laubachia lanuginosa (Hook. f. & Thomson) D. German & Al‐Shehbaz, Solms‐laubachia marinellii (Pamp.) D. German & Al‐Shehbaz, Solms‐laubachia parryoides (Kurz ex Hook. f. & T. Anderson) D. German & Al‐Shehbaz, Solms‐laubachia surculosa (N. Busch) D. German & Al‐Shehbaz, and Solms‐laubachia villosa (Maxim.) D. German & Al‐Shehbaz.     

The Response of Triticum aestivum Treated with Plant Growth Regulators to Acute Day/Night Temperature Rise

The fluctuation in temperature adversely affects grain development when the climate changes intermittently. This study investigated the effect of high day/night temperatures (34/30 °C, 38/34 °C and 42/38 °C) for two stress durations (24 h and 48 h) on Triticum aestivum. To ascertain the role of plant growth regulator (PGR) in alleviating the deleterious effects of high temperature stress, the combination of various PGRs (e.g., methyl jasmonate, salicylic acid, ascorbic acid, calcium chloride and indole acetic acid) were foliar sprayed twice; one week prior to commencement of anthesis stage and immediately after the exposure to high temperature stress. In general, the high temperature reduces plant growth, grain setting, and 100-grain weight. High temperature stress causes deterioration of plant photosynthetic machinery through a significant decline in energy dissipation, linear electron flow (LEF) and quantum yield of photosystem II (Phi2) which led to plant death. An increase in the antioxidant enzymes activity (SOD, APX, and CAT) was observed at 38/34 °C, while their activity declined sharply at 42/38 °C. Grain setting and filling were completely inhibited in plants exposed to 42/38 °C even when treated with different combinations of PGRs. Salicylic acid along with methyl jasmonate was the most effective PGR combination resulting in significant improvements in Phi2, NPQt, SOD, grain filling and grain protein content under high temperature stress. A strong correlation was observed between LEF and chlorophyll contents against the number of grains per spike and 100-grain weight. In summary, acute day and night temperature stress adversely affected wheat morphological, physiological, and yield traits, while foliar application of PGRs was partially effective in mitigating these harmful changes.

     

Autoradiographic Differentiation of Free, Bound, Pure, and Impure Thymidine-3H

Intestinal tissue from animals injected with tritium-labeled thymidine were examined by two autoradiographic methods. Conventional autoradiograms using fixed, solvent-dehydrated, paraffin-embedded tissues, and wet mounted, were compared with an autoradiographic method designed for localizing diffusible substances utilizing dry-mounted, freeze-dried frozen sections. The autoradiograms prepared by conventional methods show more than 95% of the activity located over the nucleus while, autoradiograms of intestinal tissue from the same animal prepared by the freeze-dried method shows only 88% of the activity over the nucleus. Animals injected with impure thymidine-³H, containing self-radiolysis decomposition products due to storage, led to significant alteration in the autoradiographic pattern, particularly those prepared by the freeze-dried method which show only 52% of the activity over the nucleus. Thus, conventional treatment of tissue extracted free unincorporated thymidine, metabolic products of thymidine-³H, and impurities of thymidine-³H. However, autoradiograms prepared by the dry-mounted freeze-dried method retained all the label.