Ausa poliitilise konkurentsi tagamine poliitilise reklaami piiramise kaudu

http://www.ester.ee/record=b460260

Class XI Myosins Contribute to Auxin Response and Senescence-Induced Cell Death in Arabidopsis

The integrity and dynamics of actin cytoskeleton is necessary not only for plant cell architecture but also for membrane trafficking-mediated processes such as polar auxin transport, senescence, and cell death. In Arabidopsis, the inactivation of actin-based molecular motors, class XI myosins, affects the membrane trafficking and integrity of actin cytoskeleton, and thus causes defective plant growth and morphology, altered lifespan and reduced fertility. To evaluate the potential contribution of class XI myosins to the auxin response, senescence and cell death, we followed the flower and leaf development in the triple gene knockout mutant xi1 xi2 xik (3KO) and in rescued line stably expressing myosin XI-K:YFP (3KOR). Assessing the development of primary inflorescence shoots we found that the 3KO plants produced more axillary branches. Exploiting the auxin-dependent reporters DR5::GUS and IAA2::GUS, a significant reduction in auxin responsiveness was found throughout the development of the 3KO plants. Examination of the flower development of the plants stably expressing the auxin transporter PIN1::PIN1-GFP revealed partial loss of PIN1 polarization in developing 3KO pistils. Surprisingly, the stable expression of PIN1::PIN1-GFP significantly enhanced the semi-sterile phenotype of the 3KO plants. Further we investigated the localization of myosin XI-K:YFP in the 3KOR floral organs and revealed its expression pattern in floral primordia, developing pistils, and anther filaments. Interestingly, the XI-K:YFP and PIN1::PIN1-GFP shared partially overlapping but distinct expression patterns throughout floral development. Assessing the foliar development of the 3KO plants revealed increased rosette leaf production with signs of premature yellowing. Symptoms of the premature senescence correlated with massive loss of chlorophyll, increased cell death, early plasmolysis of epidermal cells, and strong up-regulation of the stress-inducible senescence-associated gene SAG13 in 3KO plants. Simultaneously, the reduced auxin responsiveness and premature leaf senescence were accompanied by significant anthocyanin accumulation in 3KO tissues. Collectively, our results provide genetic evidences that Arabidopsis class XI myosins arrange the flower morphogenesis and leaf longevity via contributing to auxin responses, leaf senescence, and cell death

Myosin XIK is a major player in cytoplasm dynamics and is regulated by two amino acids in its tail

It has recently been found that among the 17 Arabidopsis myosins, six (XIC, XIE, XIK, XI-I, MYA1, and MYA2) have a major role in the motility of Golgi bodies and mitochondria in Nicotiana benthamiana and Nicotiana tabacum. Here, the same dominant negative tail fragments were also found to arrest the movement of Gogi bodies when transiently expressed in Arabidopsis plants. However, when a Golgi marker was transiently expressed in plants knocked out in these myosins, its movement was dramatically inhibited only in the xik mutant. In addition, a tail fragment of myosin XIK could inhibit the movement of several post-Golgi organelles, such as the trans-Golgi network, pre-vacuolar compartment, and endosomes, as well as total cytoplasmic streaming, suggesting that myosin XIK is a major player in cytoplasm kinetics. However, no co-localization of myosin tails with the arrested organelles was observed. Several deletion truncations of the myosin XIK tail were generated to corroborate function with localization. All deletion mutants possessing an inhibitory effect on organelle movement exhibited a diffuse cytoplasmic distribution. Point mutations in the tail of myosin XIK revealed that Arg1368 and Arg1443 are essential for its activity. These residues correspond to Lys1706 and Lys1779 from mouse myosin Va, which mediate the inhibitory head–tail interaction in this myosin. Therefore, such an interaction might underlie the dominant negative effect of truncated plant myosin tails and explain the mislocalization with target organelles

Transcriptome Analysis of Arabidopsis Wild-Type and gl3–sst sim Trichomes Identifies Four Additional Genes Required for Trichome Development

Transcriptome analyses have been performed on mature trichomes isolated from wild-type Arabidopsis leaves and on leaf trichomes isolated from the gl3–sst sim double mutant, which exhibit many attributes of immature trichomes. The mature trichome profile contained many highly expressed genes involved in cell wall synthesis, protein turnover, and abiotic stress response. The most highly expressed genes in the gl3–sst sim profile encoded ribosomal proteins and other proteins involved in translation. Comparative analyses showed that all but one of the genes encoding transcription factors previously found to be important for trichome formation, and many other trichome-important genes, were preferentially expressed in gl3–sst sim trichomes. The analysis of genes preferentially expressed in gl3–sst sim led to the identification of four additional genes required for normal trichome development. One of these was the HDG2 gene, which is a member of the HD–ZIP IV transcription factor gene family. Mutations in this gene did not alter trichome expansion, but did alter mature trichome cell walls. Mutations in BLT resulted in a loss of trichome branch formation. The relationship between blt and the phenotypically identical mutant, sti, was explored. Mutations in PEL3, which was previously shown to be required for development of the leaf cuticle, resulted in the occasional tangling of expanding trichomes. Mutations in another gene encoding a protein with an unknown function altered trichome branch formation

Regulation of the Escherichia coli HipBA Toxin-Antitoxin System by Proteolysis

Bacterial populations produce antibiotic-tolerant persister cells. A number of recent studies point to the involvement of toxin/antitoxin (TA) modules in persister formation. hipBA is a type II TA module that codes for the HipB antitoxin and the HipA toxin. HipA is an EF-Tu kinase, which causes protein synthesis inhibition and dormancy upon phosphorylation of its substrate. Antitoxins are labile proteins that are degraded by one of the cytosolic ATP-dependent proteases. We followed the rate of HipB degradation in different protease deficient strains and found that HipB was stabilized in a lon- background. These findings were confirmed in an in vitro degradation assay, showing that Lon is the main protease responsible for HipB proteolysis. Moreover, we demonstrated that degradation of HipB is dependent on the presence of an unstructured carboxy-terminal stretch of HipB that encompasses the last 16 amino acid residues. Further, substitution of the conserved carboxy-terminal tryptophan of HipB to alanine or even the complete removal of this 16 residue fragment did not alter the affinity of HipB for hipBA operator DNA or for HipA indicating that the major role of this region of HipB is to control HipB degradation and hence HipA-mediated persistence

A combined functional and structural genomics approach identified an EST-SSR marker with complete linkage to the Ligon lintless-2 genetic locus in cotton (Gossypium hirsutum L.)

<p>Abstract</p> <p>Background</p> <p>Cotton fiber length is an important quality attribute to the textile industry and longer fibers can be more efficiently spun into yarns to produce superior fabrics. There is typically a negative correlation between yield and fiber quality traits such as length. An understanding of the regulatory mechanisms controlling fiber length can potentially provide a valuable tool for cotton breeders to improve fiber length while maintaining high yields. The cotton (<it>Gossypium hirsutum </it>L.) fiber mutation Ligon lintless-2 is controlled by a single dominant gene (<it>Li₂</it>) that results in significantly shorter fibers than a wild-type. In a near-isogenic state with a wild-type cotton line, <it>Li₂</it>is a model system with which to study fiber elongation.</p> <p>Results</p> <p>Two near-isogenic lines of Ligon lintless-2 (<it>Li₂</it>) cotton, one mutant and one wild-type, were developed through five generations of backcrosses (BC₅). An F₂population was developed from a cross between the two <it>Li₂</it>near-isogenic lines and used to develop a linkage map of the <it>Li₂</it>locus on chromosome 18. Five simple sequence repeat (SSR) markers were closely mapped around the <it>Li₂</it>locus region with two of the markers flanking the <it>Li₂</it>locus at 0.87 and 0.52 centimorgan. No apparent differences in fiber initiation and early fiber elongation were observed between the mutant ovules and the wild-type ones. Gene expression profiling using microarrays suggested roles of reactive oxygen species (ROS) homeostasis and cytokinin regulation in the <it>Li₂</it>mutant phenotype. Microarray gene expression data led to successful identification of an EST-SSR marker (NAU3991) that displayed complete linkage to the <it>Li₂</it>locus.</p> <p>Conclusions</p> <p>In the field of cotton genomics, we report the first successful conversion of gene expression data into an SSR marker that is associated with a genomic region harboring a gene responsible for a fiber trait. The EST-derived SSR marker NAU3991 displayed complete linkage to the <it>Li₂</it>locus on chromosome 18 and resided in a gene with similarity to a putative plectin-related protein. The complete linkage suggests that this expressed sequence may be the <it>Li₂</it>gene.</p

Plant organelle dynamics:cytoskeletal control and membrane contact sites

Summary: Organelle movement and positioning are correlated with plant growth and development. Movement characteristics are seemingly erratic yet respond to external stimuli including pathogens and light. Given these clear correlations, we still do not understand the specific roles that movement plays in these processes. There are few exceptions including organelle inheritance during cell division and photorelocation of chloroplasts to prevent photodamage. The molecular and biophysical components that drive movement can be broken down into cytoskeletal components, motor proteins and tethers, which allow organelles to physically interact with one another. Our understanding of these components and concepts has exploded over the past decade, with recent technological advances allowing an even more in-depth profiling. Here, we provide an overview of the cytoskeletal and tethering components and discuss the mechanisms behind organelle movement in higher plants

Analysis of the current situation and future potential of recycling household electronics, using the example of waste management in Estonia in 2023

Bakalaureusetöö Keskkonnakaitse õppekavalElektri- ja elektroonikaseadmetejäätmed kannavad endas suurt väärtust. Nendes sisalduvad taastumatud materjalid nt väärtuslikud muldmetallid ja nendes leidub ka ohtlike aineid, mis ei tohi keskkonda sattuda. Keskkonnakoormuse vähendamiseks ja materjali maksimaalseks kasutamiseks peab elektri- ja elektroonikaseadmete jäätmeid võtma ringlusesse. Bakalaureuse töö eesmärk on kaardistada koduelektroonika jäätmete käitlemise olukorda Eestis ning võrrelda olukorda maailma suurriikide ja teiste Euroopa Liidu liikmesriikidega. Eesmärgi saavutamiseks viidi läbi viis intervjuud elektri- ja elektroonikaseadmete jäätmete käitlemisega seotud ettevõtetega ning kõrvutati Eesti ja Euroopa tasandi statistikat EE-seadmete turule laskmise, EES-jäätmete kogumise ning ringlussevõtu kohta. Teadusajakirjandusest uuriti teiste riikide EES-jäätmete käitlemise praktikaid. Tööst selgub, et liigne riigi poolt nõutav aruandlus koormab tootjavastutusorganisatsioone ja ettevõtteid, mis mõjub halvasti kõigile osapooltele. Eesti ja Euroopa Liidu statistika Eesti elektri- ja elektroonikaseadmete jäätmete kohta ei ühti – Eestil on raskusi mitme jäätmearuandlusega seotud platvormi haldamisega. Vähem järelvalvatud jäätmepunktides ei deklareerita vastuvõetavaid EES-jäätmeid õige jäätmekoodiga ja see mõjutab negatiivselt kogumise statistikat. Avalikult levib väga vähe tänapäevast elektri- ja elektroonikaseadmete jäätmete väärindamise alast kirjandust, mis pärsib ringlussevõtu tõhustamist. EES-jäätmete statistilised andmed on väga üldistavad, mis muudab keeruliseks pikaajaliste valdkondlike järelduste ja plaanide tegemise. Töö tõstab esile antud valdkonna puudujääke ja avab tulevikuks uusi uuringu suundasid.Electrical and electronic equipment waste has significant value. They contain non-renewable materials, such as valuable rare earth metals, and also hazardous substances that can not be released into the environment. To reduce environmental impact and maximize material usage, electrical and electronic equipment waste must be recycled. The goal of this bachelor's thesis is to map the state of household electronic waste management in Estonia and compare it with major world countries and other European Union member states. To achieve this goal, five interviews were conducted with companies involved in the management of electrical and electronic equipment waste. Estonian and European Union statistics about electrical and electronic equipment put on market, waste electrical and electronic equipment collection and recycling of waste were compared. Scientific literature was reviewed to investigate the electrical and electronic equipment waste management practices of other countries. The study reveals that excessive reporting requirements imposed by the state burden producer responsibility organizations and companies, negatively affecting all parties involved. Estonian and EU statistics on Estonian electrical and electronic equipment waste do not align—Estonia struggles with managing multiple waste reporting platforms. At less supervised waste collection points, electrical and electronic equipment waste is not declared with the correct waste code, negatively impacting collection statistics. There is very little modern literature on the recycling of electrical and electronic equipment waste, hindering the improvement of recycling everywhere. Statistical data on EEE waste is very generalized, making it difficult to draw long-term sector-specific conclusions and plans. The work highlights shortcomings in this field and opens new avenues for future research