Kinesin-13 regulates the quantity and quality of tubulin inside cilia

Kinesin-13, an end depolymerizer of cytoplasmic and spindle microtubules, also affects the length of cilia. However, in different models, depletion of kinesin-13 either lengthens or shortens cilia, and therefore the exact function of kinesin-13 in cilia remains unclear. We generated null mutations of all kinesin-13 paralogues in the ciliate Tetrahymena. One of the paralogues, Kin13Ap, localizes to the nuclei and is essential for nuclear divisions. The remaining two paralogues, Kin13Bp and Kin13Cp, localize to the cell body and inside assembling cilia. Loss of both Kin13Bp and Kin13Cp resulted in slow cell multiplication and motility, overgrowth of cell body microtubules, shortening of cilia, and synthetic lethality with either paclitaxel or a deletion of MEC-17/ATAT1, the α-tubulin acetyltransferase. The mutant cilia assembled slowly and contained abnormal tubulin, characterized by altered posttranslational modifications and hypersensitivity to paclitaxel. The mutant cilia beat slowly and axonemes showed reduced velocity of microtubule sliding. Thus kinesin-13 positively regulates the axoneme length, influences the properties of ciliary tubulin, and likely indirectly, through its effects on the axonemal microtubules, affects the ciliary dynein-dependent motility.     

Synthesis and in silico evaluation of 1N-methyl-1S-methyl-2-nitroethylene (NMSM) derivatives against Alzheimer disease: to understand their interacting mechanism with acetylcholinesterase

Anomalous action of human acetylcholinesterase (hAChE) in Alzheimer’s disease (AD) was restrained by various AChE inhibitors, of which the specific and potent lead candidate Donepezil is used for treating the disease AD. Besides the specificity, the observed undesirable side effects caused by Donepezil invoked the quest for new lead molecules with the increased potency and specificity for AChE. The present study elucidates the potency of six 1N-methyl-1S-methyl-2-nitroethylene (NMSM) derivatives to form a specific interaction with the peripheral anionic site and catalytic anionic subsite residues of hAChE. The NMSMs were prepared in good yield from 1,1-di(methylsulfanyl)-2-nitroethylene and primary amine (or) amino acid esters. In silico interaction analysis reveals specific and potent interactions between hAChE and selected ligand molecules. The site-specific interactions formed between these molecules also results in a conformational change in the orientation of active site residues of hAChE, which prevents them from being accessed by beta-amyloid protein (Aβ), which is a causative agent for amyloid plaque formation and acetylcholine (ACh). In silico interaction analysis between the ligand-bounded hAChE with Aß and ACh confirms this observation. The variation in the conformation of hAChE associated with the decreased ability of Aβ and ACh to access the respective functional residues of hAChE induced by the novel NMSMs favors their selection for in vivo analysis to present themselves as new members of hAChE inhibitors.     

Inhibition of growth of MOPC 104E cells in immunosuppressed mice

In this report we provide evidence that suggests that MOPC 104E may come under regulation in highly immunosuppressed hosts depleted of T cells. Mice that are adult thymectomized, total body irradiated, and transplanted with bone marrow cells were able to resist the growth of MOPC 104E cells. Spleen cells from such animals had low NK activity and no cytotoxicity against MOPC 104E, and poor response to Con A, PHA, and LPS. The animals were deficient in Lyt-1+ and Lyt-2+ cells. The growth of MOPC 104E cells was measured by using the circulating level of MOPC 104E IgM in vivo in mice treated by different modalities. We observed that inhibition of tumor growth in vivo varied with the treatment of the host. Growth was inhibited in the host in the following order: ATXBM greater than XBM greater than NORMAL greater than ATx mice.     

Maintenance of Sex-Related Genes and the Co-Occurrence of Both Mating Types in Verticillium dahliae

Verticillium dahliae is a cosmopolitan, soilborne fungus that causes a significant wilt disease on a wide variety of plant hosts including economically important crops, ornamentals, and timber species. Clonal expansion through asexual reproduction plays a vital role in recurring plant epidemics caused by this pathogen. The recent discovery of recombination between clonal lineages and preliminary investigations of the meiotic gene inventory of V. dahliae suggest that cryptic sex appears to be rare in this species. Here we expanded on previous findings on the sexual nature of V. dahliae. Only 1% of isolates in a global collection of 1120 phytopathogenic V. dahliae isolates contained the MAT1-1 idiomorph, whereas 99% contained MAT1-2. Nine unique multilocus microsatellite types comprised isolates of both mating types, eight of which were collected from the same substrate at the same time. Orthologs of 88 previously characterized sex-related genes from fungal model systems in the Ascoymycota were identified in the genome of V. dahliae, out of 93 genes investigated. Results of RT-PCR experiments using both mating types revealed that 10 arbitrarily chosen sex-related genes, including MAT1-1-1 and MAT1-2-1, were constitutively expressed in V. dahliae cultures grown under laboratory conditions. Ratios of non-synonymous (amino-acid altering) to synonymous (silent) substitutions in V. dahliae MAT1-1-1 and MAT1-2-1 sequences were indistinguishable from the ratios observed in the MAT genes of sexual fungi in the Pezizomycotina. Patterns consistent with strong purifying selection were also observed in 18 other arbitrarily chosen V. dahliae sex-related genes, relative to the patterns in orthologs from fungi with known sexual stages. This study builds upon recent findings from other laboratories and mounts further evidence for an ancestral or cryptic sexual stage in V. dahliae.     

Flexibility of Oral Cholera Vaccine Dosing—A Randomized Controlled Trial Measuring Immune Responses Following Alternative Vaccination Schedules in a Cholera Hyper-Endemic Zone

BackgroundA bivalent killed whole cell oral cholera vaccine has been found to be safe and efficacious for five years in the cholera endemic setting of Kolkata, India, when given in a two dose schedule, two weeks apart. A randomized controlled trial revealed that the immune response was not significantly increased following the second dose compared to that after the first dose. We aimed to evaluate the impact of an extended four week dosing schedule on vibriocidal response.Conclusions/SignificanceComparable immune responses and safety profiles between the two dosing schedules support the option for increased flexibility of current OCV dosing. Further operational research using a longer dosing regimen will provide answers to improve implementation and delivery of cholera vaccination in endemic and epidemic outbreak scenarios.     

Assessing the influence of habitat quality on movements of the endangered shortnose sturgeon

Movements of the endangered shortnose sturgeon Acipenser brevirostrum in the Ogeechee River (Georgia, USA) may be limited by unsuitable habitat conditions during June–September. The research objective was to determine if habitat quality is likely to impede movements and spawning of shortnose sturgeon in this system. We inserted ultrasonic transmitters in 18 adult shortnose sturgeon to monitor their monthly in-stream movements. Water quality data were collected at discrete locations along the Ogeechee River. We used geostatistical models based on Weighted Asymmetric Hydrologic Distance, in place of Euclidean distance, to predict water quality variables along the Ogeechee River, avoiding problems associated with linear distance metrics in a river network. Using ArcGIS, we constructed habitat quality models based on physiological tolerance to water temperature, dissolved oxygen, and salinity. During the summer months, tagged fish remained congregated above the fresh-saltwater interface. However, individuals appeared to move in response to changing water quality conditions. Seasonal habitat availability in other southern rivers should be similarly analyzed to assess potential relationships between the habitat and sturgeon movements. Although further laboratory and field studies are needed to better understand latitudinal variation in life history and environmental tolerances of shortnose sturgeon, the results of our study suggest that temporal and spatial variability in water quality affect habitat availability of southern populations of shortnose sturgeon.