Evaluation of fluorescent Pseudomonads and <Emphasis Type="Italic">Bacillus</Emphasis> isolates for the biocontrol of a wilt disease complex of pigeonpea

Summary Twenty isolates of fluorescent pseudomonads and Bacillus spp. were obtained from pathogen suppressive soil of a pigeonpea (Cajanus cajan) field showing wilt disease complex. These isolates were evaluated in the laboratory and screen-house for the biocontrol of wilt disease complex. Six isolates were considered to have potential for the biocontrol of the disease on the basis of antibiotic sensitivity, antifungal activity, fluorescence produced by Pseudomonas, inhibitory effect on the hatching and penetration of nematodes and colonization of pigeonpea roots by these isolates. These isolates will be further tested for their biocontrol of wilt disease complex of pigeonpea under field conditions.     

Effects of positional and geometrical isomerism on the biological activity of some novel oxazolidinones

Some novel oxazolidinone derivatives with benzotriazole as pendant have been synthesized and tested for antibacterial activity. Linearly attached benzotriazole derivative showed more potency compared to angular one in vitro. Out of E/Z-isomers of angularly attached derivatives E-isomer was found to be more potent than Z-isomer. Either less active or inactive molecules were obtained, when benzotriazole was replaced with benzimidazole, benzthiazole, or benzoxazole. Finally, thioacetamide analogue of linear compound gave a lead having activity similar to linezolid in vitro.     

cTnT1, a cardiac troponin T isoform, decreases myofilament tension and affects the left ventricular pressure waveform

Four isoforms of cardiac troponin T (cTnT), a protein essential for calcium-dependent myocardial force development, are expressed in the human; they differ in charge and length. Their expression is regulated developmentally and is affected by disease states. Human cTnT (hcTnT) isoform effects have been examined in reconstituted myofilaments. In this study, we evaluated the modulatory effects of overexpressing one cTnT isoform on in vitro and in vivo myocardial function. A hcTnT isoform, hcTnT(1), expressed during development and in heart disease but not in the normal adult heart, was expressed in transgenic (TG) mice (1-30% of total cTnT). Maximal active tension measured in skinned myocardium decreased as a function of relative hcTnT(1) expression. The pCa at half-maximal force development, Hill coefficient, and rate of redevelopment of force did not change significantly with hcTnT(1) expression. In vivo maximum rates of rise and fall of left ventricular pressure decreased, and the half-time of isovolumic relaxation increased, with hcTnT(1) expression. Substituting total cTnT charge for hcTnT(1) expression resulted in similar conclusions. Morphometric analysis and electron microscopy revealed no differences between wild-type (non-TG) and TG myocardium. No differences in isoform expression of tropomyosin, myosin heavy chain, essential and regulatory myosin light chains (MLC), TnI, or in posttranslational modifications of mouse cTnT, cTnI, or regulatory MLC were observed. These results support the hypothesis that cTnT isoform amino-terminal differences affect myofilament function and suggest that hcTnT(1) expression levels present during human development and in human heart disease can affect in vivo ventricular function.     

3D-QSAR studies on c-Src kinase inhibitors and docking analyses of a potent dual kinase inhibitor of c-Src and c-Abl kinases

Three-dimensional quantitative structure-activity relationship (3D-QSAR) analyses were carried out on quinazoline, quinoline, and cyanoquinoline derivatives inhibiting c-Src kinase. Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) 3D-QSAR models were developed. The conventional r2 values for CoMFA and CoMSIA are 0.93 and 0.89, respectively. In addition, a homology model of c-Src kinase with the activation loop resembling the active conformation was constructed using the crystal structure of the kinase domain of Lck. The ATP binding pocket of the active form of c-Src is similar to that of the c-Abl kinase in which the activation loop resembles that of an active form. One of the potent c-Src and c-Abl dual kinase inhibitors (77 or SKI-606) was docked inside the active sites of both c-Src and c-Abl. The orientation and hydrogen bonding interactions of 77 are similar in both kinases. The results of 3D-QSAR analyses and structure based studies will be useful for the design of novel c-Src and c-Abl dual kinase inhibitors.     

Comparison of Guanidine Hydrochloride (GdnHCl) and Urea Denaturation on Inactivation and Unfolding of Human Placental Cystatin (HPC)

The activity and conformational change of human placental cystatin (HPC), a low molecular weight thiol proteinase inhibitor (12,500) has been investigated in presence of guanidine hydrochloride (GdnHCl) and urea. The denaturation of HPC was followed by activity measurements, fluorescence spectroscopy and Circular Dichroism (CD) studies. Increasing the denaturant concentration significantly enhanced the inactivation and unfolding of HPC. The enzyme was 50% inactivated at 1.5 M GdnHCl or 3 M urea. Up to 1.5 M GdnHCl concentration there was quenching of fluorescence intensity compared to native form however at 2 M concentration intensity increased and emission maxima had 5 nm red shift with complete unfolding in 4–6 M range. The mid point of transition was in the region of 1.5–2 M. In case of urea denaturation, the fluorescence intensity increased gradually with increase in the concentration of denaturant. The protein unfolded completely in 6–8 M concentration of urea with a mid-point of transition at 3 M. CD spectroscopy shows that the ellipticity of HPC has increased compared to that of native up to 1.5 M GdnHCl and then there is gradual decrease in ellipticity from 2 to 5 M concentration. At 6 M GdnHCl the protein had random coil conformation. For urea the ellipticity decreases with increase in concentration showing a sigmoidal shaped transition curve with little change up to 1 M urea. The protein greatly loses its structure at 6 M urea and at 8 M it is a random coil. The urea induced denaturation follows two-state rule in which Native→Denatured state transition occurs in a single step whereas in case of GdnHCl, intermediates or non-native states are observed at lower concentrations of denaturant. These intermediate states are possibly due to stabilizing properties of guanidine cation (Gdn⁺) at lower concentrations, whereas at higher concentrations it acts as a classical denaturant.     

Fungal metabolites of (E)-guggulsterone and their antibacterial and radical-scavenging activities

Fungal transformation of (E)-guggulsterone (= (17E)-pregna-4,17-diene-3,16-dione; 1) by Rhizopus stolonifer, Fusarium lini, Cunninghamella elegans, or Gibberella fujikuroi afforded ten hydroxylated metabolites (2-11; Scheme), which were fully characterized. Compounds 4-11 have not been described yet. Some of these novel hydroxylated metabolites, as well as acetylated derivatives thereof, exhibited significant antibacterial and radical-scavenging activities (Table 3).     

Microbial transformations of gelomulide G: a member of the rare class of diterpene lactones

Microbial transformation of gelomulide G (3beta,6beta-diacetoxy-8beta,14beta-epoxyabiet-13(15)-en-16,12-olide, 1) was carried out. Incubation of 1 with Aspergillus niger afforded two new metabolites, 3beta,6beta-diacetoxy-8beta,14beta-dihydroxyabiet-13(15)-en-16,12-olide (2) and 3beta,6beta-diacetoxy-14beta-hydroxyabieta-8(9),13(15)-dien-16,12-olide (3). While Cunninghamella elegans afforded the 14-epimer of 2, i.e., 3beta,6beta-diacetoxy-8beta,14alpha-dihydroxyabiet-13(15)-en-16,12-olide (4), along with 3beta-acetoxy-6beta-hydroxy-8beta,14beta-epoxyabiet-13(15)-en-16,12-olide (5). The structures of the transformed products 2-5 were deduced to be new on the basis of MS and NMR data.     

Stability‐indicating spectrofluorimetric method for the assay of riboflavin and photoproducts: Kinetic applications

A stability‐indicating spectrofluorimetric method has been developed for the simultaneous assay of riboflavin (RF) and photoproducts, formylmethylflavin (FMF), lumichrome (LC) and lumiflavin (LF) in aqueous solution. The method is based on the extraction of LC formed in acid solution and LC and LF formed in alkaline solution with chloroform at pH 2.0 and their assay by fluorescence measurements at 478 and 530 nm, respectively. The aqueous phase, on readjustment of the pH to 6.5, is used to extract FMF with chloroform and its assay is carried out at 530 nm. The aqueous phase is then used for the assay of RF at 530 nm. The proposed method gives more accurate results for the assay of RF compared to those of the United States Pharmacopeia (USP) spectrofluorimetric method which does not take into account the presence of RF photoproducts having similar fluorescence characteristics. The proposed method along with the USP method has been applied to the study of the kinetics of photolysis of RF, assay of stored commercial vitamin preparations and their radiated samples. The results show that the USP method does not distinguish between the fluorescence of RF and its photoproducts, and, therefore, gives erroneous results with about 11% excess in the quantity of the vitamin compared to that of the proposed method. This is due to the interference of the fluorescence of photoproducts in the assay of RF. The method has been validated for various analytical parameters according to the guideline of the International Council for Harmonization (ICH).     

Adaptation strategies to climate change in marine systems

The world's oceans are highly impacted by climate change and other human pressures, with significant implications for marine ecosystems and the livelihoods that they support. Adaptation for both natural and human systems is increasingly important as a coping strategy due to the rate and scale of ongoing and potential future change. Here, we conduct a review of literature concerning specific case studies of adaptation in marine systems, and discuss associated characteristics and influencing factors, including drivers, strategy, timeline, costs, and limitations. We found ample evidence in the literature that shows that marine species are adapting to climate change through shifting distributions and timing of biological events, while evidence for adaptation through evolutionary processes is limited. For human systems, existing studies focus on frameworks and principles of adaptation planning, but examples of implemented adaptation actions and evaluation of outcomes are scarce. These findings highlight potentially useful strategies given specific social–ecological contexts, as well as key barriers and specific information gaps requiring further research and actions.     

Evolutionarily Related Dihydrofolate Reductases Perform Coequal Functions Yet Show Divergence in Their Trajectories

The enzyme dihydrofolate reductase (DHFR) catalyzes NADPH dependent reduction of dihydrofolate to tetrahydrofolate. It plays a crucial role in the DNA synthesis. The investigation of evolution of DHFR generates immense curiosity. It aids in predicting how the enzyme has adapted to the surroundings of various cell types. In spite of great similarity in the structure of E. coli DHFR and human DHFR, their primary sequences are divergent to a great extent, which is evident in variations in the kinetics mechanism of their catalysis. In presence of physiological levels of ligands, they possess distinct kinetics and different rate limiting steps. We have reviewed the process of their unfolding and refolding, their behaviour in denaturing conditions and in presence of various chaperones. Although there is structural similarity between these two homologous enzymes yet they have established distinct mechanisms to accomplish the coequal functions.