Cation-π and π-π stacking interactions allow selective inhibition of butyrylcholinesterase by modified quinine and cinchonidine alkaloids

Scaffold varied quaternized quinine and cinchonidine alkaloid derivatives were evaluated for their selective butyrylcholinesterase (BChE) inhibitory potential. K_i values were between 0.4–260.5 μM (non-competitive inhibition) while corresponding K_ivalues to acetylcholinesterase (AChE) ranged from 7.0–400 μM exhibiting a 250-fold selectivity for BChE.Docking arrangements (GOLD, PLANT) revealed that the extended aromatic moieties and the quaternized nitrogen of the inhibitors were responsible for specific π–π stacking and π–cation interactions with the choline binding site and the peripheral anionic site of BChE’s active site.     

Physical, biochemical, and immunological characterization of a thermostable amidase from Klebsiella pneumoniae NCTR 1.

An amidase capable of degrading acrylamide and aliphatic amides was purified to apparent homogeneity from Klebsiella pneumoniae NCTR 1. The enzyme is a monomer with an apparent molecular weight of 62,000. The pH and temperature optima of the enzyme were 7.0 and 65 degrees C, respectively. The purified amidase contained 11 5,5-dithiobis(2-nitrobenzoate) (DTNB)-titratable sulfhydryl (SH) groups. In the native enzyme 1.0 SH group readily reacted with DTNB with no detectable loss of activity. Titration of the next 3.0 SH groups with DTNB resulted in a loss of activity of more than 70%. The remaining seven inaccessible SH groups could be titrated only in the presence of 8 M guanidine hydrochloride. Titration of SH groups was strongly inhibited by carboxymethylation and KMnO4, suggesting the presence of SH groups at the active site(s). Inductively coupled plasma-atomic emission spectrometry analysis indicated that the native amidase contains 0.33 mol of cobalt and 0.33 mol of iron per mol of the native enzyme. Polyclonal antiserum against K. pneumoniae amidase was raised in rabbits, and immunochemical comparisons were made with amidases from Rhodococcus sp., Mycobacterium smegmatis, Pseudomonas chlororaphis B23, and Methylophilus methylotrophus. The antiserum immunoprecipitated and immunoreacted with the amidases of K. pneumoniae and P. chlororaphis B23. The antiserum failed to immunoreact or immunoprecipitate with other amidases.     

Agro-morphological and genetic diversity studies in Rice (Oryza sativa L.) germplasm using microsatellite markers

Molecular Biology Reports - Knowledge of the genetic diversity and population structure of germplasm collections is an important foundation for crop improvement. Rice production across a broad...     

Erythrocyte binding protein PfRH5 polymorphisms determine species-specific pathways of Plasmodium falciparum invasion

Some human malaria Plasmodium falciparum parasites, but not others, also cause disease in Aotus monkeys. To identify the basis for this variation, we crossed two clones that differ in Aotus nancymaae virulence and mapped inherited traits of infectivity to erythrocyte invasion by linkage analysis. A major pathway of invasion was linked to polymorphisms in a putative erythrocyte binding protein, PfRH5, found in the apical region of merozoites. Polymorphisms of PfRH5 from the A. nancymaae-virulent parent transformed the nonvirulent parent to a virulent parasite. Conversely, replacements that removed these polymorphisms from PfRH5 converted a virulent progeny clone to a nonvirulent parasite. Further, a proteolytic fragment of PfRH5 from the infective parasites bound to A. nancymaae erythrocytes. Our results also suggest that PfRH5 is a parasite ligand for human infection, and that amino acid substitutions can cause its binding domain to recognize different human erythrocyte surface receptors.     

The genotype of early-transmitting HIV gp120s promotes α (4) β(7)-reactivity, revealing α (4) β(7) +/CD4+ T cells as key targets in mucosal transmission

Mucosal transmission of HIV is inefficient. The virus must breach physical barriers before it infects mucosal CD4⁺ T cells. Low-level viral replication occurs initially in mucosal CD4⁺ T cells, but within days high-level replication occurs in Peyer''s patches, the gut lamina propria and mesenteric lymph nodes. Understanding the early events in HIV transmission may provide valuable information relevant to the development of an HIV vaccine. The viral quasispecies in a donor contracts through a genetic bottleneck in the recipient, such that, in low-risk settings, infection is frequently established by a single founder virus. Early-transmitting viruses in subtypes A and C mucosal transmission tend to encode gp120s with reduced numbers of N-linked glycosylation sites at specific positions throughout the V1-V4 domains, relative to typical chronically replicating isolates in the donor quasispecies. The transmission advantage gained by the absence of these N-linked glycosylation sites is unknown. Using primary α₄β₇ ⁺/CD4⁺ T cells and a flow-cytometry based steady-state binding assay we show that the removal of transmission-associated N-linked glycosylation sites results in large increases in the specific reactivity of gp120 for integrin- α₄β₇. High-affinity for integrin α₄β₇, although not found in many gp120s, was observed in early-transmitting gp120s that we analyzed. Increased α₄β₇ affinity is mediated by sequences encoded in gp120 V1/V2. α₄β₇-reactivity was also influenced by N-linked glycosylation sites located in C3/V4. These results suggest that the genetic bottleneck that occurs after transmission may frequently involve a relative requirement for the productive infection of α₄β₇ ⁺/CD4⁺ T cells. Early-transmitting gp120s were further distinguished by their dependence on avidity-effects to interact with CD4, suggesting that these gp120s bear unusual structural features not present in many well-characterized gp120s derived from chronically replicating viruses. Understanding the structural features that characterize early-transmitting gp120s may aid in the design of an effective gp120-based subunit vaccine.     

Synthesis and antimicrobial activity of 7-fluoro-3-aminosteroids

A series of 7-fluoro-3-aminosteroids were synthesized and their in vitro antimicrobial activities were evaluated against Gram-positive and Gram-negative bacteria. The nucleophilic fluorination of several 7beta-hydroxysteroids by diethylaminosulfur trifluoride in n-pentane, followed by reductive amination of the resulting 7-fluoro-3-ketosteroids with spermidine in the presence of NaBH(3)CN, afforded 7-fluoro-3-aminosteroids in high yield. Compound 25 showed the highest antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pyogenes, and Escherichia coli.     

Genome-wide identification,evolution and expression analysis of cyclic nucleotide-gated channels in tobacco (Nicotiana tabacum L.)

Tobacco (Nicotiana tabacum) serve as the top leading commercial, non-food, and model crop worldwide. Cyclic nucleotide-gated channels (CNGCs) are ligand-gated, calcium-permeable, divalent, cation-selective channels, involved in important biological functions. Here, we systematically characterized thirty-five CNGC genes in the genome of Nicotiana tabacum, and classified into four phylogenetic groups. Evolutionary analysis showed that NtabCNGC family of N. tabacum originated from the parental genome of N. sylvestris and N. tomentosiformis, and further expanded via tandem and segmental duplication events. Tissue-specific expression analysis showed that twenty-three NtabCNGC genes are involved in the development of various tobacco tissues. Subsequent RT-qPCR analyses indicated that these genes are sensitive towards external abiotic and biotic stresses. Notable performances were exhibited by group-I and IV CNGC genes against black shank, Cucumber mosaic virus, Potato virus Y, cold, drought, and cadmium stresses. Our analyses also suggested that NtabCNGCs can be regulated by phosphorylation and miRNAs, and multiple light, temperature, and pathogen-responsive cis-acting regulatory elements present in promotors. These results will be useful for elaborating the biological roles of NtabCNGCs in tobacco growth and development.     

Rice-associated antagonistic bacteria suppress the Fusarium fujikoroi causing rice bakanae disease

BioControl - Rice bakanae disease, caused by Fusarium fujikoroi, is an economically important disease that poses a threat to rice cultivation. It causes serious yield losses quantitatively and...     

Weight Loss and Impact on Quality of Life in Parkinson’s Disease

IntroductionWeight loss is common in Parkinson’s Disease (PD) and sometimes may precede the diagnosis. Weight loss is associated with multiple factors but its impact on health-related quality of life (HRQL) in PD remains unknown. We sought to investigate the factors associated with weight change and to quantify its effect on HRQL.MethodsThe National Parkinson Foundation Quality Improvement Initiative (NPF-QII) data was used to analyze PD patients longitudinally between two visits, separated by 12±6 months. Multiple linear regression analyses were used to assess the associations between baseline covariates and body weight change per month, and to evaluate whether, and to what degree, Parkinson’s Disease Questionnaire (PDQ-39) scores were affected.ResultsA higher Hoehn & Yahr stage, higher number of comorbidities, older age, lower MOCA estimate, and higher rate of levodopa usage were observed in patients who lost weight. Multivariate regression analysis indicated that age and levodopa usage were significantly associated with weight loss. Furthermore, monthly body weight loss was significantly associated with HRQL decline in PD patients. Loss of 1 lb (0.45 kg) per month was associated with a decline in QOL: an increase of 0.5% in PDQ-39 Summary Index score (p=0.004), and 1.1% and 1.5% increases in the mobility and ADL dimensions, respectively.ConclusionWeight loss in PD is common and seems to correlate with worsened HRQL. Awareness of factors associated with weight loss and its relation to HRQL may help practitioners improve patient management and expectations.