KNL1 Binding to PP1 and Microtubules Is Mutually Exclusive

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Geriatric dentistry--meet the need

Geriatric dentistry or gerodontics is the delivery of dental care to older adults involving the diagnosis, prevention, and treatment of problems associated with normal ageing and age-related diseases as part of an inter-disciplinary team with other health care professionals. Geriatric health is an ignored and under-explored area worldwide. Oral health reflects overall well being for the elderly population. Conversely, elderly patients are more predisposed to oral conditions due to age-related systemic diseases and functional changes. The major barriers to practising geriatric dentistry are the lack of trained faculty members, a crowded curriculum and monetary concerns. For successful treatment, the practitioner must adopt a humanitarian approach and develop a better understanding of the feelings and attitudes of the elderly. Prevention and early intervention strategies must be formulated to reduce the risk of oral diseases in this population. In future, dental professionals must have a proper understanding of the magnitude of the services to be provided to the elderly. This could only be realised through an education programme in geriatric dentistry, which should be started without further delay. This article hence sets out the objectives, needs, present scenario, strategies and types of dental treatment required by the elderly population.     

Probing the DNA sequence specificity of Escherichia coli RECA protein

Escherichia coli RecA protein catalyzes the central DNA strand-exchange step of homologous recombination, which is essential for the repair of double-stranded DNA breaks. In this reaction, RecA first polymerizes on single-stranded DNA (ssDNA) to form a right-handed helical filament with one monomer per 3 nt of ssDNA. RecA generally binds to any sequence of ssDNA but has a preference for GT-rich sequences, as found in the recombination hot spot Chi (5′-GCTGGTGG-3′). When this sequence is located within an oligonucleotide, binding of RecA is phased relative to it, with a periodicity of three nucleotides. This implies that there are three separate nucleotide-binding sites within a RecA monomer that may exhibit preferences for the four different nucleotides. Here we have used a RecA coprotease assay to further probe the ssDNA sequence specificity of E.coli RecA protein. The extent of self-cleavage of a λ repressor fragment in the presence of RecA, ADP-AlF₄ and 64 different trinucleotide-repeating 15mer oligonucleotides was determined. The coprotease activity of RecA is strongly dependent on the ssDNA sequence, with TGG-repeating sequences giving by far the highest coprotease activity, and GC and AT-rich sequences the lowest. For selected trinucleotide-repeating sequences, the DNA-dependent ATPase and DNA-binding activities of RecA were also determined. The DNA-binding and coprotease activities of RecA have the same sequence dependence, which is essentially opposite to that of the ATPase activity of RecA. The implications with regard to the biological mechanism of RecA are discussed.     

Simultaneous determination and quantification of three pentacyclic triterpenoids—betulinic acid,oleanolic acid,and ursolic acid—in cell cultures of <Emphasis Type="BoldItalic">Lantana camara</Emphasis> L.

A simple procedure has been described for simultaneous determination and improved yield of three pentacyclic triterpenoids—betulinic, oleanolic, and ursolic acids—from callus cultures of Lantana camara. Cell biomass was obtained from leaf disk explants cultured on Murashige and Skoog (Physiol Plant 15:473–497, 1962) medium supplemented with 5 μM 6-benzylaminopurine, 1 μM 2,4-dichlorophenoxyacetic acid, and 1 μM α-naphthaleneacetic acid. Optimum separation of the three compounds was achieved by reverse-phase high-pressure liquid chromatography on a C₁₈ column with 80:20 (v/v) acetonitrile/water as mobile phase. With this route, a yield of 3.1% betulinic acid, 1.88% oleanolic acid, and 4.12% ursolic acid per gram dry weight was obtained from cultures. Leaves from the parent plant, used as control, showed total absence of betulinic acid, and the quantities of oleanolic and ursolic acids present in them were only marginally higher than that found in in vitro-raised cultures. Presence of the three compounds was further confirmed by electrospray ionization mass spectrometry.     

Evaluation of Cr(VI) Exposed and Unexposed Plant Parts of Tradescantia pallida (Rose) D. R. Hunt. for Cr Removal from Wastewater by Biosorption

Phytoremediation is an efficient method for the removal of heavy metals from contaminated systems. A productive disposal of metal accumulating plants is a major concern in current scenario. In this work, Cr(VI) accumulating Tradescantia pallida plant parts were investigated for its reuse as a biosorbent for the removal of Cr(VI) ions. The effect of pH, contact time, sorbent dosage, Cr(VI) concentration and temperature was examined to optimize these process parameters. Results showed that Cr(VI) exposed/unexposed T. pallida leaf biomass could remove 94% of chromium with a sorption capacity of 64.672 mg g^?1. Whereas the kinetics of Cr(VI) biosorption was well explained by the pseudo second-order kinetic model, the Langmuir model better described the data on Cr(VI) sorption isotherm compared with the Freundlich model. The changes in the free energy (ΔG°), entropy (ΔS°) and enthalpy (ΔH°) were found to be ?5.276 kJ mol^?1, 0.391 kJ mol^?1 K^?1 and 11.346 kJ mol^?1, respectively, which indicated the process to be spontaneous, feasible and endothermic in nature. FTIR spectra of T. pallida leaf biomass revealed the active participation of ligands, such as ?NH, amide, hydroxyl and sulphonate groups present in the biomass for Cr(VI) binding, SEM analysis revealed a porous structure of the biosorbent for an easy uptake of Cr(VI).     

Effect of culture conditions on synthesis of triterpenoids in suspension cultures of Lantana camara L.

Present report is aimed to study the batch kinetics of Lantana camara. Dynamic changes of parameters, such as pH, conductivity, wet and dry cell concentrations, consumption of major nutrients, carbon source and agitation speeds were investigated to understand the culture characteristics of suspended cells grown on MS + BAP + 2,4-D + NAA in shake flasks. Results indicated that the consumption of phosphate resulted in the onset of stationary phase in cultures. Maltose as carbon source resulted in production of maximum triterpenoid content (31.08 mg/L) while the least was found on glucose (10.69 mg/L). Notably, both did not support accumulation of betulinic acid. Sucrose, although stood second in terms of quantity (21.6 mg/L), supported the production of all the three triterpenoids-oleanolic, ursolic and betulinic acids. Maximum viable cultures were obtained at a rotation speed of 120 rpm. The present finding will form a background for further scale-up related studies.     

Disparate associations of HLA class I markers with HIV-1 acquisition and control of viremia in an African population

Background

Acquisition of human immunodeficiency virus type 1 (HIV-1) infection is mediated by a combination of characteristics of the infectious and the susceptible member of a transmission pair, including human behavioral and genetic factors, as well as viral fitness and tropism. Here we report on the impact of established and potential new HLA class I determinants of heterosexual HIV-1 acquisition in the HIV-1-exposed seronegative (HESN) partners of serodiscordant Zambian couples.

Methodology/Principal Findings

We assessed the relationships of behavioral and clinically documented risk factors, index partner viral load, and host genetic markers to HIV-1 transmission among 568 cohabiting couples followed for at least nine months. We genotyped subjects for three classical HLA class I genes known to influence immune control of HIV-1 infection. From 1995 to December 2006, 240 HESNs seroconverted and 328 remained seronegative. In Cox proportional hazards models, HLA-A*68:02 and the B*42-C*17 haplotype in HESN partners were significantly and independently associated with faster HIV-1 acquisition (relative hazards = 1.57 and 1.55; p = 0.007 and 0.013, respectively) after controlling for other previously established contributing factors in the index partner (viral load and specific class I alleles), in the HESN partner (age, gender), or in the couple (behavioral and clinical risk score). Few if any previously implicated class I markers were associated here with the rate of acquiring infection.

Conclusions/Significance

A few HLA class I markers showed modest effects on acquisition of HIV-1 subtype C infection in HESN partners of discordant Zambian couples. However, the striking disparity between those few markers and the more numerous, different markers found to determine HIV-1 disease course makes it highly unlikely that, whatever the influence of class I variation on the rate of infection, the mechanism mediating that phenomenon is identical to that involved in disease control.     

Physiological evidence indicates microcystin-LR to be a part of quantitative chemical defense system

The functional role of microcystins (MC) is poorly understood. Here, we investigated the effect of pure MC-LR recovered from the freshwater planktonic cyanobacterium Nostoc sp. BHU001 on five closely related cyanobacteria (Nostoc muscorum, Nostoc commune, Anabaena fertilissima, Anabaena doliolum, and Cylinderospermum majus) isolated from different habitats as well as on the producer itself (Nostoc sp. BHU001). MC-LR was found to be a general growth inhibitor active at nanomolar range (25–100 μg L^?1). It inhibited the growth of all cyanobacterial strains in a concentration-dependent manner, except the producer. A. fertilissima was the most sensitive species. MC-LR affected vital metabolic processes such as photosynthesis, respiration, and nitrogen fixation. Nitrogenase activity showed maximum sensitivity, followed by respiration, photosynthesis, and general growth. The photosynthetic electron transport activity was maximally inhibited at PSI, followed by whole chain and PSII activities. Thus, MC-LR is active at multiple sites causing energy constraint to the vital metabolic processes of the target organisms. However, its requirement at high concentration, which is environmentally irrelevant, and lack of quantitative information on the extracellular release of MC-LR suggest that MC-LR has no allelopathic function and could be a part of a quantitative chemical defense system.     

Enhancement of vincristine under in vitro culture of Catharanthus roseus supplemented with Alternaria sesami endophytic fungal extract as a biotic elicitor

International Microbiology - Vincristine, one of the major vinca alkaloid of Catharanthus roseus (L.) G. Don. (Apocynaceae), was enhanced under in vitro callus culture of C. roseus using fungal...