Role of the Kinesin-like Protein KipB in Aspergillus nidulans

Molecular motors are protein machines, which power almost all forms of movement in the living world. Among the best known are the motors that hydrolyze ATP and use the derived energy to generate force. They are involved in a variety of diverse cellular functions as vesicle and organelle transport, cytoskeleton dynamics, morphogenesis, polarized growth, cell movements, spindle formation, chromosome movement, nuclear fusion, and signal transduction. Three superfamilies of molecular motors, kinesins, dyneins, and myosins, have so far been well characterized. These motors use microtubules (in the case of kinesines and dyneins) or actin filaments (in the case of myosins) as tracks to transport cargo materials within a cell. Analysis of fungal genomes revealed at least 10 distinct kinesins in filamentous fungi, some of which are not found in yeasts. We used the motor domain of conventional kinesin (KinA) from Aspergillus nidulans to perfom BLAST searches at the public A. nidulans genome database, at the Whitehead Center for Genome Research (Cambridge USA), and identified eleven putative kinesin motors. They grouped into nine of the eleven families, two kinesins being found in the Unc104 familiy and interestingly, one did not fall into any of the known families. The present work analyses the function of a kinesin-like protein in A. nidulans, KipB, which is a member of the Kip3 kinesin family. This family includes one representative in Saccharomyces cerevisiae (Kip3, the family founding member), two in Schizosaccharomyces pombe, Klp5 and Klp6 and one in Drosophila, Klp67A, the single one reported so far for higher eukaryotes in this family. Kip3 kinesins are implicated in microtubule disassembly and are required for chromosome segregation in mitosis and meiosis. To assess the function of KipB kinesin in A. nidulans, a kipB disruption strain was constructed. Analysis of the DkipB mutant revealed new features concerning the cellular functions of Kip3 proteins, but also some conserved ones. kipB is not essential for vegetative growth, and meiosis and ascospore formation were not affected in the DkipB mutant. The KipB protein was shown to be involved in the turnover of interphase cytoplasmic, mitotic and astral microtubules. DkipB mutants are less sensitive to the microtubule-destabilizing drug benomyl, and the microtubule cytoskeleton of interphase cells in DkipB mutants appears altered. Interestingly, spindle morphology and positioning were severely affected. Spindles were highly mobile, could overpass each other, moved over long distances through the cytoplasm, and displayed in 64% of the cases an extremely bent shape, latter feature being the first time reported for Kip3 kinesins. Mitotic progression was delayed in the DkipB mutant and a higher number of cytoplasmic microtubules remained intact during mitosis. DkipB heterozygous strains showed an increased instability of diploid nuclei, which proved once more KipB involvement in mitosis, along with DkipB clear genetic interaction with a mutation in another mitotic kinesin in A. nidulans, bimC4. An N-terminal GFP-KipB construct localized to cytoplasmic microtubules in interphase cells and to spindle and astral microtubules during mitosis, in a discontinuous pattern. Speckles of GFP-KipB appeared to be aligned in the cell. Time-lapse video microscopy indicated that the spots were moving independently towards the microtubule plus ends. This advanced the hypothesis that KipB could display processivity and intrinsic motility along microtubules, or that other kinesins involved in organelle motility are able to target the KipB protein to the microtubule plus ends. In the case of C-terminally truncated GFP-KipB protein versions, a stronger GFP signal was obtained and colocalization with a-tubulin-GFP revealed that they uniformly stain cytoplasmic, mitotic and astral microtubules. This suggests that the C-terminus is important for the correct localization and the movement of KipB protein along microtubules

Expression of citrulline and homocitrulline residues in the lungs of non-smokers and smokers : implications for autoimmunity in rheumatoid arthritis

Introduction: Smoking is a well-established risk factor for rheumatoid arthritis (RA), and it has been proposed that smoking-induced citrullination renders autoantigens immunogenic. To investigate this mechanism, we examined human lung tissue from 40 subjects with defined smoking status, with or without chronic obstructive pulmonary disease (COPD), and control tissues from other organs for citrullinated proteins and the deiminating enzymes peptidylarginine deiminase type-2 (PAD2) and -4 (PAD4). Methods: Lung tissue samples, dissected from lobectomy specimens from 10 never smokers, 10 smokers without airflow limitation, 13 COPD smokers and eight COPD ex-smokers, and control tissue samples (spleen, skeletal muscle, liver, ovary, lymph node, kidney and heart), were analysed for citrullinated proteins, PAD2 and PAD4 by immunoblotting. Citrulline and homocitrulline residues in enolase and vimentin were analysed by partial purification by gel electrophoresis followed by mass spectrometry in 12 of the lung samples and one from each control tissues. Band intensities were scored semi-quantitatively and analysed by two-tailed Mann-Whitney T-test. Results: Within the lung tissue samples, citrullinated proteins, PAD2 and PAD4 were found in all samples, with an increase in citrullination in COPD (P = 0.039), but minimal difference between smokers and non-smokers (P = 0.77). Citrullination was also detected at lower levels in the tissues from other organs, principally in lymph node, kidney and skeletal muscle. Mass spectrometry of the lung samples showed that vimentin was citrullinated at positions 71, 304, 346, 410 and 450 in non-smokers and smokers both with and without COPD. A homocitrulline at position 104 was found in four out of six COPD samples and one out of six non-COPD. Citrulline-450 was also found in three of the control tissues. There were no citrulline or homocitrulline residues demonstrated in a-enolase. Conclusions: We have shown evidence of citrullination of vimentin, a major autoantigen in RA, in both non-smokers and smokers. The increase in citrullinated proteins in COPD suggests that citrullination in the lungs of smokers is mainly due to inflammation. The ubiquity of citrullination of vimentin in the lungs and other tissues suggests that the relationship between smoking and autoimmunity in RA may be more complex than previously thought

Induktion homöostatischer Plastizität im menschlichen Motorkortex durch konvergierende kortikokortikale Eingänge

In dieser Studie wurde mittels zwei interventioneller TMS-Protokolle Homöostase-ähnliche Metaplastizität der Hand-Region im menschlichen primären Motorkortex induziert. Kombiniert wurden hierfür zwei TMS-Protokolle, die über unterschiedliche Afferenzen Plastizität im primären Motorkortex bewirken. Die Hypothese war, dass im linken primäre Motorkortex eine homöostatische Integration von synaptischer Langzeitpotentierung- und Langzeitdepression-ähnlicher Plastizität stattfinden würde. Dafür wurde zehn gesunden Probanden repetitive transkranielle Magnetstimulation (rTMS) des linken prämotorischen Kortex (PMD) appliziert, um so einen LTP-ähnlichen Anstieg (5 Hz rTMS) oder einen LTD-ähnlichen Abfall (1 Hz rTMS) der kortikospinalen Erregbarkeit des linken M1HAND via prämotorisch-motorischer Afferenzen zu induzieren. Gefolgt wurde die PMD rTMS, von einer gepaart-assoziativen Stimulation (PAS) appliziert am rechten N. medianus und linken M1HAND, um hierdurch eine vom Zeitpunkt der Potentialentstehung abhängige Plastizität in sensorisch-motorischen Afferenzen des linken M1 zu induzieren. Hierbei zeigte sich, dass, eine nach einer fazilitierenden 5 Hz rTMS gegebene, faszilitierende PASN20+2ms die kortikospinale Erregbarkeit herabsetzte. Genauso kam es bei einer, nach einer hemmenden 1Hz rTMS gegebenen, ebenfalls hemmenden PASN20-5ms zu einer gesteigerten kortikospinalen Erregbarkeit. Demnach induzierte eine prämotorisch-motorische Präkonditionierung eine homöostatische Antwort auf eine sensorisch-motorische PAS. Es zeigte sich ein negativ-linearer Zusammenhang zwischen den Veränderungen der Erregbarkeit induziert durch PMD rTMS und denen hervorgerufen durch eine anschließende PAS. Diese Veränderungen der Erregbarkeit waren nicht begleitet von parallelen Veränderungen der motorischen Leistungsfähigkeit einer Finger-Tipp-Übung. Die Ergebnisse geben Hinweise auf ein homöostatisches Antwortmuster im menschlichen M1, das akute plastische Veränderungen, die durch unterschiedliche Zugänge entstanden sind, integriert

Polymorphisms in genes related to the hypothalamic-pituitary-adrenal axis and antidepressant response – Systematic review

Objective: Around 50% of depressed patients do not respond to antidepressants. Evidence from familial studies suggests a genetic component to this. This study investigated whether patients with polymorphisms in genes related to the hypothalamic-pituitary-adrenal (HPA) axis were less likely to respond to antidepressants. Method: EMBASE, MEDLINE, PsycINFO, and the Cochrane Library were searched. Inclusionary criteria were: 1) patients with depression, 2) study of HPA axis-related candidate genes, 3) at least four weeks of antidepressants, and 4) assessment of depressive symptoms dividing patients into non-responders and responders. Results: Nineteen studies were identified. Non-responders and responders did not differ in single nucleotide polymorphisms (SNPs) in genes encoding arginine vasopressin. Findings were equivocal regarding genes encoding the FK506 binding protein 5 and glucocorticoid and mineralocorticoid receptors. Specific SNPs and haplotypes within genes related to corticotropin-releasing hormone (CRHBP, CRHR1) and melanocortins (POMC) predicted non-responder status. Conclusions: Replication studies and additional investigations exploring gene x environment and drug x environment interactions are necessary before pharmacological treatments may be adjusted based on a patient’s genetic profile

Mindfulness-Based Stress Reduction and Change in Health-Related Behaviors

How best to support change in health-related behaviors is an important public health challenge. The role of mindfulness training in this process has received limited attention. We sought to explore whether mindfulness training is associated with changes in health-related behaviors. The Health Behaviors Questionnaire was used to obtain self-reported dietary behaviors, drinking, smoking, physical activity and sleep quality before and after attendance at an eight-week Mindfulness-Based Stress Reduction program. T-test for paired data and chi-square were used to compare pre-post intervention means and proportions of relevant variables with p = .05 as level of significance. Participants (n = 174; mean age 47 years, range: 19-68; 61 % female) reported significant improvements in dietary behaviors and sleep quality. Partial changes were seen in drinking and physical activity, and no change in smoking. In conclusion, mindfulness training promotes favorable changes in selected health-related behaviors deserving further study through randomized controlled trials

Testing the Effectiveness of the Health Belief Model in Predicting Preventive Behavior During the COVID-19 Pandemic: The Case of Romania and Italy

none5sìWe use a cultural psychology approach to examine the relevance of the Health Belief Model (HBM) for predicting a variety of behaviors that had been recommended by health officials during the initial stages of the COVID-19 lockdown for containing the spread of the virus and not overburdening the health system in Europe. Our study is grounded in the assumption that health behavior is activated based on locally relevant perceptions of threats, susceptibility and benefits in engaging in protective behavior, which requires careful attention to how these perceptions might be structured and activated. We assess the validity of the HBM in two European countries that have been relatively understudied, using simultaneous measurements during acute periods of infection in Romania and Italy. An online questionnaire provided a total of (N = 1863) valid answers from both countries. First, to understand individual difference patterns within and across populations, we fit a General Linear Model in which endorsement was predicted by behavior, country, their interaction, and a random effect for participants. Second, we assess the effect of demographics and health beliefs on prevention behaviors by fitting a multi-group path model across countries, in which each behavior was predicted by the observed health belief variables and demographics. Health beliefs showed stronger relationships with the recommended behaviors than demographics. Confirming previously reported relationships, self-efficacy, perceived severity, and perceived benefits were consistently related to the greater adoption of individual behaviors, whereas greater perceived barriers were related to lower adoption of health behaviors. However, we also point to important location specific effects that suggest that local norms shape protective behavior in highly contextualized ways.openKarl, Johannes Alfons; Fischer, Ronald; Druică, Elena; Musso, Fabio; Stan, AnastasiaKarl, Johannes Alfons; Fischer, Ronald; Druică, Elena; Musso, Fabio; Stan, Anastasi

Foobaz: Variable Name Feedback for Student Code at Scale

Current traditional feedback methods, such as hand-grading student code for substance and style, are labor intensive and do not scale. We created a user interface that addresses feedback at scale for a particular and important aspect of code quality: variable names. We built this user interface on top of an existing back-end that distinguishes variables by their behavior in the program. Therefore our interface not only allows teachers to comment on poor variable names, they can comment on names that mislead the reader about the variable's role in the program. We ran two user studies in which 10 teachers and 6 students created and received feedback, respectively. The interface helped teachers give personalized variable name feedback on thousands of student solutions from an edX introductory programming MOOC. In the second study, students composed solutions to the same programming assignments and immediately received personalized quizzes composed by teachers in the previous user study.Massachusetts Institute of Technology (Amar Bose Teaching Fellowship)Quanta Computer (Firm) (Qmulus Project