Prometaphase spindle maintenance by an antagonistic motor-dependent force balance made robust by a disassembling lamin-B envelope

We tested the classical hypothesis that astral, prometaphase bipolar mitotic spindles are maintained by balanced outward and inward forces exerted on spindle poles by kinesin-5 and -14 using modeling of in vitro and in vivo data from Drosophila melanogaster embryos. Throughout prometaphase, puncta of both motors aligned on interpolar microtubules (MTs [ipMTs]), and motor perturbation changed spindle length, as predicted. Competitive motility of purified kinesin-5 and -14 was well described by a stochastic, opposing power stroke model incorporating motor kinetics and load-dependent detachment. Motor parameters from this model were applied to a new stochastic force-balance model for prometaphase spindles, providing a good fit to data from embryos. Maintenance of virtual spindles required dynamic ipMTs and a narrow range of kinesin-5 to kinesin-14 ratios matching that found in embryos. Functional perturbation and modeling suggest that this range can be extended significantly by a disassembling lamin-B envelope that surrounds the prometaphase spindle and augments the finely tuned, antagonistic kinesin force balance to maintain robust prometaphase spindles as MTs assemble and chromosomes are pushed to the equator.     

Many-body energies during proton transfer in an aqueous system

The energetics of the mechanism of proton transfer from a hydronium ion to one of the water molecules in its first solvation shell are studied using density functional theory and the Møller–Plesset perturbation (MP2) method. The potential energy surface of the proton transfer mechanism is obtained at the B3LYP and MP2 levels with the 6-311++G** basis set. Many-body analysis is applied to the proton transfer mechanism to obtain the change in relaxation energy, two-body, three-body and four-body energies when proton transfer occurs from the hydronium ion to one of the water molecules in its first solvation shell. It is observed that the binding energy (BE) of the complex decreases during the proton transfer process at both levels of theory. During the proton transfer process, the % contribution of the total two-body energy to the binding energy of the complex increases from 62.9 to 68.09% (39.9 to 45.95%), and that of the total three-body increases from 25.9 to 27.09% (24.16 to 26.17%) at the B3LYP/6-311++G** (MP2/ 6-311++G**) level. There is almost no change in the water–water–water three-body interaction energy during the proton transfer process at both levels of theory. The contribution of the relaxation energy and the total four-body energy to the binding energy of the complex is greater at the MP2 level than at the B3LYP level. Significant differences are found between the relaxation energies, the hydronium–water interaction energies and the four-body interaction energies at the B3LYP and MP2 levels.     

New natural urease inhibitors from Ranunculus repens

Phytochemical investigations on the chloroform and ethyl acetate soluble fractions of the roots of Ranunculus repens led to the isolation of methyl 3,4,5-trihydroxybenzoate 1, R(+)- 4-methoxydalbergione 2 and R(+)-dalbergiophenol 3. The structures of these compounds were established through spectral studies including 1D and 2D NMR experiments and by comparison with literature data. These compounds showed potent inhibitory activity against urease.     

Differential expression of genes encoding calmodulin-binding proteins in response to bacterial pathogens and inducers of defense responses

Calmodulin (CaM) plays an important role in sensing and transducing changes in cellular Ca²⁺ concentration in response to several biotic and abiotic stresses. Although CaM is implicated in plant-pathogen interactions, its molecular targets and their role in defense signaling pathway(s) are poorly understood. To elucidate the signaling pathways that link CaM to defense responses, we screened a cDNA library constructed from bean leaves undergoing a hypersensitive response (HR) with radiolabeled CaM isoforms. A total of 26 putative CBPs were identified. Sequencing of the cDNAs revealed that they represent 8 different genes. They are homologues of previously identified CaM-binding proteins (CBPs) in other systems. However, some CBPs are novel members of known CBP families. The proteins encoded by these clones bound CaM in a Ca²⁺-dependent manner. To determine if these CBPs are involved in plant defense responses, we analyzed their expression in bean leaves inoculated with compatible, incompatible and nonpathogenic bacterial strains. Expression of three CBPs including an isoform of cyclic nucleotide-gated channels (PvCNGC-A) and two hypothetical proteins (PvCBP60-C and PvCBP60-D) was induced whereas the expression of two other isoforms of CNGCs (PvCNGC-Band PvCNGC-C) was repressed in response to incompatible pathogens. The expression of the rest, a small auxin up RNA (PvSAUR1) and two hypothetical proteins (PvCBP60-Aand PvCBP60-B), was not changed. The expression of most of the pathogen-regulated genes was also affected by salicylic acid, jasmonic acid, hydrogen peroxide and a fungal elicitor, which are known to induce defense responses. Our results strongly suggest that at least five bean CBPs are involved in plant defense responses.     

The GLH proteins,Caenorhabditis elegans P granule components,associate with CSN-5 and KGB-1, proteins necessary for fertility,and with ZYX-1, a predicted cytoskeletal protein

The GLH proteins belong to a family of four germline RNA helicases in Caenorhabditis elegans. These putative ATP-dependent enzymes localize to the P granules, which are nonmembranous complexes of protein and RNA exclusively found in the cytoplasm of all C. elegans germ cells and germ cell precursors. To determine what proteins the GLHs bind, C. elegans cDNA libraries were screened by the yeast two-hybrid method, using GLHs as bait. Three interacting proteins, CSN-5, KGB-1, and ZYX-1, were identified and further characterized. GST pull-down assays independently established that these proteins bind GLHs. CSN-5 is closely related to the subunit 5 protein of COP9 signalosomes, conserved multiprotein complexes of plants and animals. RNA interference (RNAi) with csn-5 results in sterile worms with small gonads and no oocytes, a defect essentially identical to that produced by RNAi with a combination of glh-1 and glh-4. KGB-1 is a putative JNK MAP kinase that GLHs bind. A kgb-1 deletion strain has a temperature-sensitive, sterile phenotype characterized by the absence of mature oocytes and the presence of trapped, immature oocytes that have undergone endoreplication. ZYX-1 is a LIM domain protein most like vertebrate Zyxin, a cytoskeletal adaptor protein. In C. elegans, while zyx-1 appears to be a single copy gene, neither RNAi depletion nor a zyx-1 deletion strain results in an obvious phenotype. These three conserved proteins are the first members in each of their families reported to associate with germline helicases. Similar to the loss of GLH-1 and GLH-4, loss of either CSN-5 or KGB-1 causes oogenesis to cease, but does not affect the initial assembly of P granules.     

Inhibition of DMBA Induced Rat Mammary Duct Damage by Novel Synthetic Organoselenium Compounds.

The balance between prooxidants and antioxidants is crucial to the survival and functioning of aerobic organisms. Partially reduced derivatives of oxygen, which are produced in aerobic organisms as part of normal physiological and metabolic processes, are toxic species, oxidizing numerous biomolecules, which initiate tissue injury and cell death. DMBA (7,12-dimethylbenz[a]anthracene) is a polycyclic aromatic hydrocarbon (PAH) known to cause tumors in rats. DMBA is known to generate DNA-reactive species, which may enhance oxidative stress in cells, during its metabolism. Besides the formation of DNA adducts, oxidative products derived from mutagen metabolism, such as DMBA, might impair vital cellular functions by damaging proteins and lipid membranes. Synthetic organoselenium compounds inhibit the initiation phase of carcinogenesis by inhibiting DMBA-DNA adduct formation in the target organ in vivo. Because of the health problems induced by many environmental pollutants, many efforts have been undertaken to evaluate the relative antioxidant potential of selenium and synthetic organoselenium compounds. We undertook the present study to evaluate the chemopreventive potential of the novel synthetic organoselenium compounds (1-isopropyl-3-methylbenzimidazole-2-selenone (SeI) and 1,3-di-p-methoxybenzylpyrimidine-2-selenone (SeII)) in the well-established DMBA-treated rat model by monitoring the extent of lipid peroxidation and mammary duct damage. In this study, adult female Wistar rats were treated with DMBA and the novel organoselenium compounds (SeI and SeII) in determined doses. In DMBA-treated rats, the effects of the organoselenium compounds on malondialdehyde (MDA) levels and histological changes in the rat mammary lactiferous duct were studied. The ability of the organoselenium compounds to prevent oxidative damage induced by DMBA in rat mammary ducts was demonstrated. Protection against lipid peroxidation measured as MDA in the SeI and SeII treated groups was provided by the novel synthesized organoselenium compounds. SeI and SeII both provided chemoprevention against DMBA-induced oxidative stress in the rat mammary duct.     

Novel Quinazolinone Derivatives: Potential Synthetic Analogs for the Treatment of Glaucoma,Alzheimer's Disease and Diabetes Mellitus

Quinazolinones, which represent an important part of nitrogen-containing six-membered heterocyclic compounds, are frequently used in drug design due to their wide biological activity properties. Therefore, the novel quinazolinones were synthesized from the reaction of acylated derivatives of 4-hydroxy benzaldehyde with 3-amino-2-alkylquinazolin-4(3H)-ones with good yields (85–94 %) and their structures were characterized using Fourier-transform Infrared (FT-IR), Nuclear Magnetic Resonance (¹H-NMR, ¹³C-NMR), and High-Resolution Mass Spectroscopy (HR-MS). As the application of the synthesized compounds, their inhibition properties of the synthesized compounds on α-Glucosidase (α-Glu), Acetylcholinesterase (AChE), Butyrylcholinesterase (BChE), and Carbonic anhydrase I–II (hCA I–II) metabolic enzymes were investigated. All compounds showed inhibition at nanomolar level with the K_i values in the range of 12.73±1.26–93.42±9.44 nM for AChE, 8.48±0.92–25.84±2.59 nM for BChE, 66.17±5.16–818.06±44.41 for α-Glu, 2.56±0.26–88.23±9.72 nM for hCA I, and 1.68±0.14–85.43±7.41 nM for hCA II. Molecular docking study was performed to understand the interactions of the most potent compounds with corresponding enzymes. Also, absorption, distribution, metabolism, excretion, and toxicity (ADME/T) properties of the compounds were investigated.     

Control experiments usingAgrotis segetum granulosis virus againstAgrotis ipsilon [Lep.: Noctuidae] on tobacco seedlings in Northern Pakistan

Agrotis segetum Schiff. granulosis virus propagated in Denmark was applied against released 2nd instar larvae ofAgrotis ipsilon (Hfn.) in tobacco plots in nurseries at Peshawar and Bhurbun (Murree), Northern Pakistan. Nursery bed plots were isolated from the surroundings by net roof and plastic sheets. Granulosis virus concentrations used were 5×10⁷ and 10⁹ capsules per ml water, and 250 ml water per plot (1–4 m²). Reductions of cutworms as well as cutworm damages varied between 72 and 100% as compared to plots only treated with water. Addition of active coal to the GV did not increase reduction percentages. A possible effect of the GV could be traced one year after treatment.

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Résumé Le virus de la granulose d'Agrotis segetum Schiff. multiplié au Danemark a été appliqué contre le 2^e stade des chenilles deAgrotis ipsilon (Hfn.) dans des parcelles expérimentales à Peshawar et Bhurbun (Murree), Pakistan du nord. Les parcelles isolées avec des filets et des feuilles plastiques furent infestées artificiellement en chenilles. Les concentrations de GV utilisées furent de 5×10⁷ et 10⁹ granules par ml d'eau, 250 ml de la suspension préparée étant distribués par parcelle de 1 à 4 m². La réduction du nombre de chenilles et celui des plantes endommagées varie de 72 à 100% par rapport aux notations effectuées dans les parcelles traitées avec de l'eau pure. L'addition du charbon actif au GV n'augmente pas son effet. Une action du traitement a été retrouvée un an après l'application.