nMAT4, a maturase factor required for nad1 pre‐mRNA processing and maturation,is essential for holocomplex I biogenesis in Arabidopsis mitochondria

Group II introns are large catalytic RNAs that are found in bacteria and organellar genomes of lower eukaryotes, but are particularly prevalent within mitochondria in plants, where they are present in many critical genes. The excision of plant mitochondrial introns is essential for respiratory functions, and is facilitated in vivo by various protein cofactors. Typical group II introns are classified as mobile genetic elements, consisting of the self‐splicing ribozyme and its own intron‐encoded maturase protein. A hallmark of maturases is that they are intron‐specific, acting as cofactors that bind their intron‐containing pre‐RNAs to facilitate splicing. However, the degeneracy of the mitochondrial introns in plants and the absence of cognate intron‐encoded maturase open reading frames suggest that their splicing in vivo is assisted by ‘trans’‐acting protein factors. Interestingly, angiosperms harbor several nuclear‐encoded maturase‐related (nMat) genes that contain N‐terminal mitochondrial localization signals. Recently, we established the roles of two of these paralogs in Arabidopsis, nMAT1 and nMAT2, in the splicing of mitochondrial introns. Here we show that nMAT4 (At1g74350) is required for RNA processing and maturation of nad1 introns 1, 3 and 4 in Arabidopsis mitochondria. Seed germination, seedling establishment and development are strongly affected in homozygous nmat4 mutants, which also show modified respiration phenotypes that are tightly associated with complex I defects.     

Reversible pegylation prolongs the hypotensive effect of atrial natriuretic peptide

Natriuretic peptides (NP), including atrial natriuretic peptide (ANP), induce potent natriuresis and vasodilation and thereby generate hypotension in vivo. Despite intensive efforts, clinical application of NP as an antihypertensive agent is limited because of their short biological half-life and poor bioavailability. Recently, we have developed a strategy that facilitates slow release of peptides from PEG-peptide inactive conjugates, based on reversible pegylation. Peptides prepared by this approach undergo slow, spontaneous chemical hydrolysis at physiological conditions, releasing the native active peptide/protein drug from the inactive conjugates over prolonged periods. A PEG chain of 30 kDa was linked covalently to the alpha-amino side chain of the hormone via a MAL-Fmoc-NHS spacer, yielding PEG 30-Fmoc-ANP, a prodrug that releases the native hormone upon incubation at physiological conditions. Bolus administration of native ANP to Wistar rats receiving adrenaline yields a short, transitory effect in lowering blood pressure (BP), reaching a maximum at 2 min, and then returning to control values after 12 to 25 min. In contrast, administration of PEG 30-Fmoc-ANP lowered BP following a lag period of 50 min, and maintained low BP for a period exceeding 60 min. Saline or PEG 30-Fmoc-Alanine were not effective in lowering BP in Wistar rats. These results show that the novel compound, PEG 30-Fmoc-ANP, is a reversible pegylated prodrug derivative that facilitates a prolonged BP lowering effect in rats and may be considered as a candidate for development into an antihypertensive drug.     

大鼠食管胸段，腹段乙酰胆碱酯酶阳性神经的配布

大鼠食管胸段和腹段壁内乙酰胆碱酯酶（ＡＣｈＥ）阳性神经存在于神经束和分支的粗细神经纤维内,也见于外膜丛,肌间丛,粘膜下丛和粘膜肌内。食管肌层内ＡＣｈＥ阳性神经纤维多而密集,而食管腹段肌内尤为丰富,肌间神经纤维末梢分布于肌束表面,可能与控制肌纤维活动有关;分布于肌内,粘膜下层和上皮基部的ＡＣｈＥ阳性神经中,尚含有内脏感觉神经纤维。食管壁的肌间丛和粘膜下丛内散在有多极形和卵园形的ＡＣｈＥ阳性神经元,在食管腹段内数多,而以中小型神经元为主。     

Education for sustainability in higher education: a multiple-case study of three courses

Education for sustainability (EfS) in higher education is an emerging specialisation within the general field of EfS. EfS encompasses cognitive, affective and behavioural aspects, and aims at enhancing a variety of learning outcomes in these domains and reaching students from all programmes. One of the main challenges for higher education educators is to design courses in a way that will effectively promote the various learning outcomes of EfS. A central question is how sustainability should be integrated into the curriculum; which topics should be taught and which pedagogies ought to be applied to improve students’ knowledge, skills and motivation to promote sustainable living. The present study aimed to contribute to the knowledge about students’ learning outcomes yielded by different designs of EfS courses. This multiple-case study of three courses used a mixed-methods design. For each course, we identified its characteristics and analysed students’ self-reported learning outcomes. We found that: (1) a course with a higher degree of participatory learning, employing a system approach, promoted the highest and most varied learning outcomes; (2) the lecture-based course yielded the fewest learning outcomes; and (3) field trips promoted learning outcomes only when accompanied by more advanced pedagogies.     

Safety,Immunogenicity and Duration of Immunity Elicited by an Inactivated Bovine Ephemeral Fever Vaccine

Bovine ephemeral fever (BEF) is an economically important viral vector-borne cattle disease. Several live-attenuated, inactivated and recombinant vaccines have been tested, demonstrating varying efficacy. However, to the best of our knowledge, duration of immunity conferred by an inactivated vaccine has never been reported. In the last decade, Israel has faced an increasing number of BEF outbreaks. The need for an effective vaccine compatible with strains circulating in the Middle East region led to the development of a MONTANIDE™ ISA 206 VG (water-in-oil-in-water), inactivated vaccine based on a local strain. We tested the safety, immunogenicity and duration of immunity conferred by this vaccine. The induced neutralizing antibody (NA) response was followed for 493 days in 40 cows vaccinated by different protocols. The vaccine did not cause adverse reactions or a decrease in milk production. All cows [except 2 (6.7%) which did not respond to vaccination] showed a significant rise in NA titer of up to 1:256 following the second, third or fourth booster vaccination. Neutralizing antibody levels declined gradually to 1:16 up to 120 days post vaccination. This decline continued in cows vaccinated only twice, whereas cows vaccinated 3 or 4 times showed stable titers of approximately 1:16 for up to 267 days post vaccination. At least three vaccinations with the inactivated BEF vaccine were needed to confer long-lasting immunity. These results may have significant implications for the choice of vaccination protocol with inactivated BEF vaccines. Complementary challenge data should however be added to the above results in order to determine what is the minimal NA response conferring protection from clinical disease.     

Structure-Function Analysis of Nucleolin and ErbB Receptors Interactions

Background

The ErbB receptor tyrosine kinases and nucleolin are major contributors to malignant transformation. Recently we have found that cell-surface ErbB receptors interact with nucleolin via their cytoplasmic tail. Overexpression of ErbB1 and nucleolin leads to receptor phosphorylation, dimerization and anchorage independent growth.

Methodology/Principal Findings

In the present study we explored the regions of nucleolin and ErbB responsible for their interaction. Using mutational analyses, we addressed the structure–function relationship of the interaction between ErbB1 and nucleolin. We identified the ErbB1 nuclear localization domain as nucleolin interacting region. This region is important for nucleolin-associated receptor activation. Notably, though the tyrosine kinase domain is important for nucleolin-associated receptor activation, it is not involved in nucleolin/ErbB interactions. In addition, we demonstrated that the 212 c-terminal portion of nucleolin is imperative for the interaction with ErbB1 and ErbB4. This region of nucleolin is sufficient to induce ErbB1 dimerization, phosphorylation and growth in soft agar.

Conclusions/Significance

The oncogenic potential of ErbB depends on receptor levels and activation. Nucleolin affects ErbB dimerization and activation leading to enhanced cell growth. The C-terminal region of nucleolin and the ErbB1 NLS-domain mediate this interaction. Moreover, when the C-terminal 212 amino acids region of nucleolin is expressed with ErbB1, it can enhance anchorage independent cell growth. Taken together these results offer new insight into the role of ErbB1 and nucleolin interaction in malignant cells.     

In vitro DNA and RNA synthesis by human platelets.

In vitro incorporation of [Me-3H] thymidine and [5-3H] uridine into human platelets was demonstrated. Thymidine incorporation was inhibited by three specific inhibitors of DNA synthesis: hydroxyurea, cytosine arabinoside and daunomycin. The effect was dose-dependent. Uridine uptake by platelets was found to be inhibited by specific inhibitors of RNA synthesis such as actinomycin D, rifampicin and vincristine, the effect of actinomycin D being dose dependent. The drug also led to a time-dependent inhibition of protein synthesis when preincubated with platelets. The platelet RNA profile on polyacrylamide gel was demonstrated to be similar to that of embryonic mouse erythroblast RNA. Synthesis of all three fractions, 28 S, 18 S and 4 S, was inhibited by actinomycin D. These findings show that human platelets are capable of DNA and RNA synthesis, and that these activities play a role in controlling protein synthesis in these cells. Detectable amounts of DNA have been found in whole human platelets, and in isolated mitochondria derived from these cells. Isolated platelet mitochondria incorporated [3H] thymidine and [3H] uridine into their macromolecules. These activities were inhibited by daunomycin and by both rifampicin and actinomycin D, respectively. These results support the assumption that DNA and RNA synthesis found in intact cell preparations takes place most probably in platelet mitochondria.     

不同时辰电针对大鼠杏仁核一氧化氮合酶表达的影响

目的观察不同时辰电针对大鼠杏仁核一氧化氮合酶(NOS)表达的影响.方法采用还原型尼克酰胺腺嘌呤二核苷酸脱氢酶(NADPH-d)法,观察不同时辰电针大鼠一侧"足三里"穴对杏仁核NOS表达的影响.结果电针对大鼠杏仁皮质内侧核群、基底外侧核群NOS的表达有上调作用,并存在时辰差异(P<0.05);电针对大鼠杏仁中央核NOS表达无明显作用(P>0.05).结论电针对大鼠杏仁核NOS表达的影响有时辰差异.     

Specific interactions of divalent metal ions with a DNA duplex containing the d(CA)n/(GT)n tandem repeat

Divalent metal ions are essential for maintaining functional states of the DNA molecule. Their participation in DNA structure is modulated by the base sequence and varies depending on the nature of the ion. The present investigation addresses the interaction of Ca2+ ions with a tandem repeat of two CA dinucleotides, (CA)2/(TG)2. The binding of Ca2+ to the repeat is monitored by nuclear magnetic resonance (NMR) spectroscopy using chemical shift mapping. Parallel experiments monitor binding of Mg2+ ions to the repeat as well as binding of each ion to a DNA duplex in which the (CA)2/(TG)2 repeat is eliminated. The results reveal that the direction and the magnitude of chemical shift changes induced by Ca2+ ions in the NMR spectra of the repeat are different from those induced by Mg2+ ions. The differences between the two cations are significantly diminished by the elimination of the (CA)2/(TG)2 repeat. These findings suggest a specific interaction of Ca2+ ions with the (CA)2/(TG)2 motif. The specificity of the interaction resides in the two A-T base pairs of the repeat, and it involves the major groove of the first A-T base pair and both grooves of the second A-T base pair.