On a restricted occupancy model and its applications

With the multivariate hypergeometric distribution as a background certain occupancy distributions useful in practical applications are derived. More specifically it is assumed that a sample of n individuals is drawn from a population consisting of m types with r individuals in each type, (i) without replacement and (ii) by returning the selected individual in the population and with it another individual of the same type. The distributions of the number Z of distinct types observed in the sample are obtained in both cases in terms of the numbers. Assuming, in addition to the m equiprobable types of individuals, the existence of a control type, say, with s individuals, the joint distribution of the number U of distinct types observed in the sample and the number V of individuals of the control type present in the sample is obtained in terms of the numbers C(n, k, r) and the marginal distribution of U in terms of the Gould-Hopper numbers. Using these distributions minimum variance unbiased estimators of the number m of types are derived. Moreover small sample tests based on the zero frequency are constructed.     

Estimating the Number of Droplets and Drug Particles Emitted from MDIs

The objective of this paper is to assess the number of drug particles or droplets contained in metered dose inhaler (MDI) aerosols. Equations were developed to estimate this. The number of drug particles was estimated to be as high as about 300 million for QVAR solution MDIs and as low as 670,000 for Beclovent MDIs. The number of particles in MDI aerosols was shown to be highly dependent on the mass median aerodynamic diameter (MMAD) and geometric standard deviation, and to a lesser extent the total mass of the aerosol. It was demonstrated that when the number of particles are calculated assuming that the aerosol is monodisperse and using the MMAD as the particle size, the number of particles are significantly underestimated. The number of droplets atomized from HFA-134a MDIs was estimated to range from about 220 million to about 1.1 billion droplets per actuation. For solution MDIs, each of the atomized droplets contains drug and thus the number of drug particles is the same as the number of atomized droplets. However, for suspension MDI formulations many of the droplets do not contain any micronized drug particles and the number of drug particles is much lower than the number of atomized droplets.     

Estimation of Finite and Closed Population Size: An Inverse Sampling Approach with Unequal Recapture Probability

Based on capture-mark-recapture sampling methods the problem of estimating unknown population size was considered. The sampling started with the assumption that at the beginning of the experiment all the individuals were unmarked, and the unmarked individuals caught in each sample will be marked and returned to the original population before the next sample is drawn. It is also assumed that the population is closed by birth, death, emigration and immigration. Using a general inverse sampling approach, the unknown population size N is estimated by a maximum likelihood estimator (MLE), and a simple form for approximate MLE is obtained. The probability function for S (the minimum number of samples required to be drawn to have L (L ≥ 1) samples, each of which contains at least one marked individual) and the form for E[S] are also obtained. In addition, corrections and improvements of some previous works in this field are given.     

Generation of native-like protein structures from limited NMR data,modern force fields and advanced conformational sampling

Determining an accurate initial native-like protein fold is one of the most important and time-consuming steps of de novo NMR structure determination. Here we demonstrate that high-quality native-like models can be rapidly generated from initial structures obtained using limited NOE assignments, through replica exchange molecular dynamics refinement with a generalized Born implicit solvent (REX/GB). Conventional structure calculations using an initial sparse NOE set were unable to identify a unique topology for the zinc-bound C-terminal domain of E. coli chaperone Hsp33, due to a lack of unambiguous long range NOEs. An accurate overall topology was eventually obtained through laborious hand identification of long range NOEs. However we were able to obtain high-quality models with backbone RMSD values of about 2 Å with respect to the final structures, using REX/GB refinement with the original limited set of initial NOE restraints. These models could then be used to make further assignments of ambiguous NOEs and thereby speed up the structure determination process. The ability to calculate accurate starting structures from the limited unambiguous NOE set available at the beginning of a structure calculation offers the potential of a much more rapid and automated process for NMR structure determination. Jianhan Chen: Authors contributed equally to this work.Hyung-Sik Won: Authors contributed equally to this work.     

The Negative Binomial Distribution of Order k and Some of Its Properties

The negative binomial distribution of order k is introduced and briefly studied. First it is shown that it is a proper probability distribution. Then its probability generating function, mean and variance are derived. Finally it is shown that the number of trials until the rth kth consecutive success (r ≧ 1, k ≧ 1) in independent trials with constant success probability p (0 < p < 1) is distributed as negative binomial distribution of order k. The present paper generalizes results of SHANE (1973), PHILIPPOU and MUWAFI (1982), and PHILIPPOU, GEORGHIOU and PHILIPPOU (1982).     

向日葵花盘水溶性多糖提取工艺及抗氧化研究

目的:研究了向日葵花盘中水溶性粗多糖的提取工艺及抗氧化性能.方法:采用单因素试验和L_9(3~4)正交试验设计,对多糖提取工艺进行优化,并采用Fenton体系和邻苯三酚自氧化法评价了该提取物的体外抗氧化能力.结果:优化工艺条件为:提取温度95℃、料液比1:20、提取时间4h,向日葵水溶性粗多糖得率为9.73%,其中温度是影响粗多糖提取的重要因素.结论:结果表明向日葵水溶性粗多糖有较好的抗氧化活性.     

早熟金柚果皮挥发油的提取及GC-MS分析

采用水蒸气蒸馏法提取早熟金柚果皮挥发油,通过正交实验优选获得早熟金柚果皮挥发油提取的工艺参数,结果表明：早熟金柚果皮挥发油的最佳提取工艺是将柚皮粉碎60 s,加水5倍,提取6 h。采用GC-MS联用技术对早熟金柚果皮挥发油的化学成分进行分离鉴定,共分离出44个峰,鉴定出了其中的25种化合物,占峰面积的98.43%。用面积归一化法测定了各个组分的相对百分含量,其主要成分有柠檬烯（65.82%）、β-月桂烯（25.52%）、4-侧柏烯（1.78%）、紫苏烯（0.44%）、氧化芳樟醇（0.42%）。     

Characterization, by Size, Density, Osmotic Fragility, and Immunoaffinity, of Acetylcholine- and Vasoactive Intestinal Polypeptide-Containing Storage Particles from Myenteric Neurones of the Guinea-Pig

When cytoplasmic extracts of guinea-pig myenteric neurones are submitted to centrifugal density gradient fractionation in a zonal rotor acetylcholine is bimodally distributed in the gradient, in a peak (I) rich in synaptic vesicles of the classic type and in a denser peak (II/VI) rich in densecored vesicles and vasoactive intestinal polypeptide (VIP). The putative stable synaptic vesicle markers synaptophysin (p38), vesicular proteoglycan, and Mg2+-activated ATPase were also bimodally distributed, with a peak coincident with peak I and another, broader peak embracing peak II/VI, and neighbouring peaks of other neuropeptides resolved from peak II/VI by the density gradient separation procedure used. To establish whether the stable markers, acetylcholine and VIP in peak II/VI were present in one particle or several, attempts were made to separate them by particle-exclusion chromatography and differential osmotic fragility. These were unsuccessful, leading us to conclude that the storage particles in peak II/VI contain both neurotransmitters and all three putative stable synaptic vesicle markers. It is suggested that such particles are the counterparts, in cholinergic neurones of the myenteric plexus, of the dense-cored, enkephalin- and noradrenaline-containing vesicles of certain adrenergic neurones and, like the latter, may exist in a precursor-product relationship with the classic synaptic vesicles containing the small-molecular-mass transmitters and found in the same nerve terminals.     

Organogenesis from hypocotyl thin cell layers of Lupinus mutabilis and Lupinus albus

When thin cell layers (TCLn), isolated from the nodalregion of the hypocotyl of 5 day old seedlings, werecultured in medium M1 with IAA and BA, entire plantswere obtained from L. mutabilis explants andprolific shoots from L. albus explants.Histological studies carried out on L. mutabilisTCLn showed that meristematic cells, present in theexplants at the time of inoculation, gave rise to theformation of a primary meristem resulting inorganogenesis. In TCLn where apical or axillarymeristematic cells were absent, we observed theformation of a nodular structure with a cambium-likelayer at its periphery which divided to form a primarymeristem leading to organogenesis. Plant regenerationfrom TCLn may be useful in genetic transformationassays.     

Transition of hemoglobin between two tertiary conformations: determination of equilibrium and thermodynamic parameters from the reaction of 5,5'-dithiobis(2-nitrobenzoate) with the CysF9[93]beta sulfhydryl group

The equilibrium constant of the reaction of 5,5'-dithiobis(2-nitrobenzoate) with the CysF9[93]beta sulfhydryl group of hemoglobin decreases by 2 to 3 orders of magnitude between pH 5.6 and 9. The reaction is coupled to the ionizations of two groups on the protein. At 25 degrees C one group has a pK(a) of 5.31+/-0.2 when hemoglobin is in its (tertiary) r conformation, typified by the thiolate anion form of CysF9[93]beta; this changes to 7.73+/-0.4 in the (tertiary) t conformation, typified by the mixed disulfide form of the sulfhydryl. The second group ionizes with a pK(a) of 7.11+/-0.4 in the r conformation; this changes to 8.38+/-0.2 in the t conformation. K(rt), the equilibrium constant for the r<-->t isomerization process, is 0.22+/-0.06. The standard enthalpy and entropy changes for the isomerization are DeltaH(o)(rt)=24.2 kJ mol(-1) and DeltaS(o)(rt)=68.8 JK(-1)mol(-1), respectively.     

Heterogeneity of photosynthetic membranes from Rhodobacter capsulatus: Size dispersion and ATP synthase distribution

The density distribution of photosynthetic membrane vesicles (chromatophores) from Rhodobacter capsulatus has been studied by isopicnic centrifugation. The average vesicle diameters, examined by electron microscopy, varied between 61 and 72 nm in different density fractions (70 nm in unfractionated chromatophores). The ATP synthase catalytic activities showed maxima displaced toward the higher density fractions relative to bacteriochlorophyll, resulting in higher specific activities in those fractions (about threefold). The amount of ATP synthase, measured by quantitative Western blotting, paralleled the catalytic activities. The average number of ATP synthases per chromatophore, evaluated on the basis of the Western blotting data and of vesicle density analysis, ranged between 8 and 13 (10 in unfractionated chromatophores). Poisson distribution analysis indicated that the probability of chromatophores devoid of ATP synthase was negligible. The effects of ATP synthase inhibition by efrapeptin on the time course of the transmembrane electric potential (evaluated as carotenoid electrochromic response) and on ATP synthesis were studied comparatively. The ATP produced after a flash and the total charge associated with the proton flow coupled to ATP synthesis were more resistant to efrapeptin than the initial value of the phosphorylating currents, indicating that several ATP synthases are fed by protons from the same vesicle.     

Biodiversity and distribution of epibiontic communities on Caridina ensifera (Crustacea,Decapoda, Atyidae) from Lake Poso: comparison with another ancient lake system of Sulawesi (Indonesia)

Fernandez‐Leborans, G. and von Rintelen, K. 2010. Biodiversity and distribution of epibiontic communities on Caridina ensifera (Crustacea, Decapoda, Atyidae) from Lake Poso: comparison with another ancient lake system of Sulawesi (Indonesia). — Acta Zoologica (Stockholm) 91 : 163–175 The epibiont communities of the shrimp Caridina ensifera, endemic to Lake Poso (Sulawesi, Indonesia), were analysed. Most of the epibiont species were ciliated protozoa belonging to three suctorian genera (Acineta, Podophrya and Spelaeophrya), three peritrich genera (Zoothamnium, Vorticella and Cothurnia), and a haptorid genus (Amphileptus). There was also a rotifer epibiont of the genus Embata. Epibionts were identified to species level. There were 14 to 1114 epibionts per shrimp. The distribution of the epibiont species on the surface of the basibiont was recorded, calculating the number on the different colonized individuals of C. ensifera. The most abundant species, Zoothamnium intermedium and Acineta sulawesiensis, were also the most widely distributed. There was a significant difference between the spatial distributions of the different epibiont species. The analysis of the number of the epibiont species throughout the anteroposterior axis of the shrimp showed a gradient from the anterior to the posterior end of the body. Data from Lake Poso were compared with those of the Malili lake system (Sulawesi), obtained from its endemic shrimp, Caridina lanceolata. Lake Poso had the highest mean diversity, while Lake Mahalona showed the highest maximum diversity. All lakes were correlated with respect to the mean number of epibionts on the anatomical units of the shrimp, which showed a similar general distribution. The distributions of the different epibiont species were compared between the lakes. The possible adaptations of the epibionts as well as the colonization patterns were discussed. From the statistical results and the analysis of the distributions, we propose that in these communities epibiont species have a pattern of colonization in which they follow a behaviour as a whole; each species has a differential distribution, with the species occupying the available substratum with the particular requirements of each functional group, but there is a trend towards maintaining an equilibrium among species and groups, compensating for diversity and number of individuals. In all lakes there was an epibiont distribution model comprising the maintenance of an anteroposterior axis gradient, which was supported by the fluctuation in diversity and number of individuals of the different functional groups of epibiont species. The functional role of the different groups of species seems to tend towards sustainability with little global variation among the lakes.     

Determination of G-protein levels,ADP-ribosylation by cholera and pertussis toxins and the regulation of adenylyl cyclase activity in liver plasma membranes from lean and genetically diabetic (db/db)

Liver plasma membranes prepared from genetically diabetic (db/db) mice expressed levels of G_i α-2, G_i α-3 and G-protein β-subunits that were reduced by some 75, 63 and 73% compared with levels seen in membranes from lean animals. In contrast, there were no significant differences in the expression of the 42 and 45 kDa forms of G_s α-subunits. Pertussis toxin-catalysed ADP-ribosylation of membranes from lean animals identified a single 41 kDa band whose labelling was reduced by some 86% in membranes from diabetic animals. Cholera toxin-catalysed ADP-ribosylation identified two forms of G_s α-subunits whose labelling was about 4-fold greater in membranes from diabetic animals compared with those from lean animals. Maximal stimulations of adenylyl cyclase activity by forskolin (100 μM), GTP (100 μM), p[NH]ppG (100 μM), NaF (10 mM) and glucagon (10 μM) were similar in membranes from lean and diabetic animals, whereas stimulation by isoprenaline (100 μM) was lower by about 22%. Lower concentrations (EC₅₀-60 nM) of p[NH]ppG were needed to activate adenylyl cyclase in membranes from diabetic animals compared to those from lean animals (EC₅₀-158 nM). As well as causing activation, p[NH]ppG was capable of eliciting a pertussis toxin-sensitive inhibitory effect upon forskolin-stimulated adenylyl cyclase activity in membranes from both lean and diabetic animals. However, maximal inhibition of adenylyl cyclase activity in membranes from diabetic animals was reduced to around 60% of that found using membranes from lean animals. Pertussis toxin-treatment in vivo enhanced maximal stimulation of adenylyl cyclase by glucagon, isoprenaline and p[NH]ppG through a process suggested to be mediated by the abolition of functional G_i activity. The lower levels of expression of G-protein β-subunits, in membranes from diabetic compared with lean animals, is suggested to perturb the equilibria between holomeric and dissociated G-protein subunits. We suggest that this may explain both the enhanced sensitivity of adenylyl cyclase to stimulation by p[NH]ppG in membranes from diabetic animals and the altered ability of pertussis and cholera toxins to catalyse the ADP-ribosylation of G-proteins in membranes from these two animals.     

Crystal Structure Determination and Functional Characterization of the Metallochaperone SlyD from Thermus thermophilus

SlyD (sensitive to lysis D; product of the slyD gene) is a prolyl isomerase [peptidyl-prolyl cis/trans isomerase (PPIase)] of the FK506 binding protein (FKBP) type with chaperone properties. X-ray structures derived from three different crystal forms reveal that SlyD from Thermus thermophilus consists of two domains representing two functional units. PPIase activity is located in a typical FKBP domain, whereas chaperone function is associated with the autonomously folded insert-in-flap (IF) domain. The two isolated domains are stable and functional in solution, but the presence of the IF domain increases the PPIase catalytic efficiency of the FKBP domain by 2 orders of magnitude, suggesting that the two domains act synergistically to assist the folding of polypeptide chains. The substrate binding surface of SlyD from T. thermophilus was mapped by NMR chemical shift perturbations to hydrophobic residues of the IF domain, which exhibits significantly reduced thermodynamic stability according to NMR hydrogen/deuterium exchange and fluorescence equilibrium transition experiments. Based on structural homologies, we hypothesize that this is due to the absence of a stabilizing β-strand, suggesting in turn a mechanism for chaperone activity by ‘donor-strand complementation.’ Furthermore, we identified a conserved metal (Ni²⁺) binding site at the C-terminal SlyD-specific helical appendix of the FKBP domain, which may play a role in metalloprotein assembly.     

Isolation and amino acid composition of two somatostatin-like peptides from ovine hypothalamus: somatostatin-28 and somatostatin-25

Two $\text{b}$-type cytochrome components, differing in their mid-point redox potentials as well as their reactivities toward CO, are demonstrated in the membrane particle of $\text{Azotobacter}\text{vinelandii}$ by potentiometric titration. The low redox component is revealed to be CO-reactive while the higher redox component is not. Accordingly, the later cytochrome is believed not to be directly involved in the reduction of oxygen while the former component is the cytochrome $\text{o}$ of $\text{Azotobacter}$.     

Eimeria procyonis sp. n., an Isospora sp., and a Redescription of E. nuttalli Yakimoff and Matikaschwili, 1932 (Protozoa: Eimeriidae) from the American Raccoon (Procyon lotor)

SYNOPSIS. Thirty-two of 48 raccoons examined were infected with a previously undescribed species of Eimeria which is herein named E. procyonis. Of the 32 infected animals, 10 also harbored E. nuttalli and 1 had Isospora sp. oocysts.
The ellipsoid to ovoid oocysts of E. procyonis measured 23.4 × 18.0 (16–29 × 13–24) μm; its sporocysts measured 12.1 × 9.3 (11.5–15 × 7–10) μm, each containing a slightly flattened substiedal body. The sporocyst residuum consisted of numerous scattered granules each ∼1 μm in diameter. The oocyst wall was double-layered. The outer layer appeared rough and pitted, measuring 1.5 μm, except at the micropyle where it was 1 μm thick.
The oocysts of the Isospora sp. measured 16.8 × 13.7 (16–18.5 × 12.5–15.5) μm. The wall consisted of a single layer ∼0.5 μm thick. The sporocysts measured 11.2 × 9.1 (9.5–11.5 × 8–10) μm, and each contained 4 elongate sporozoites. The oocysts of E. nuttalli measured 17.5 × 13.6 (12-21 × 11-15) μm, with a smooth single-layered wall approximately 0.7 μm thick. The sporocysts measured 12.2 × 7.1 (9-13 × 5.5–11) μm. Each sporocyst had a thin, dark, Stieda body and the sporocyst residuum consisted of many fine granules.     

A novel complexity-to-diversity strategy for the diversity-oriented synthesis of structurally diverse and complex macrocycles from quinine

Recent years have witnessed a global decline in the productivity and advancement of the pharmaceutical industry. A major contributing factor to this is the downturn in drug discovery successes. This can be attributed to the lack of structural (particularly scaffold) diversity and structural complexity exhibited by current small molecule screening collections.Macrocycles have been shown to exhibit a diverse range of biological properties, with over 100 natural product-derived examples currently marketed as FDA-approved drugs. Despite this, synthetic macrocycles are widely considered to be a poorly explored structural class within drug discovery, which can be attributed to their synthetic intractability.Herein we describe a novel complexity-to-diversity strategy for the diversity-oriented synthesis of novel, structurally complex and diverse macrocyclic scaffolds from natural product starting materials. This approach exploits the inherent structural (including functional) and stereochemical complexity of natural products in order to rapidly generate diversity and complexity. Readily-accessible natural product-derived intermediates serve as structural templates which can be divergently functionalized with different building blocks to generate a diverse range of acyclic precursors. Subsequent macrocyclisation then furnishes compounds that are each based around a distinct molecular scaffold. Thus, high levels of library scaffold diversity can be rapidly achieved. In this proof-of-concept study, the natural product quinine was used as the foundation for library synthesis, and six novel structurally diverse, highly complex and functionalized macrocycles were generated.     

Anti-inflammatory activity of rhein isolated from the flowers of Cassia fistula L. and possible underlying mechanisms

Objective

Anti-inflammatory activity of rhein in animal models with potential mechanism of actions.

Influence of castration-induced testosterone and estradiol deficiency on obesity and glucose metabolism in male Göttingen minipigs

Low testosterone and estradiol concentrations are predictive for the development of the metabolic syndrome in men and women, respectively. The aim of this study was to investigate the influence of sex hormone deficiency on food intake, body weight, body composition and glucose metabolism in male Göttingen minipigs.Five adult male Göttingen minipigs were studied before castration (pre-cast), 10-18 days (post-cast 1) and 10-11 weeks (post-cast 2) after castration. Parameters of interest were food intake, body weight, body fat percentage and sex hormone concentrations. Furthermore glucose tolerance, glucagon suppression, insulin resistance, beta cell function and disposition index were evaluated by oral and intravenous glucose tolerance tests.Castration led to almost complete disappearance of circulating testosterone and estradiol and secondarily to increased food intake, body weight and body fat percentage. Ten-eighteen days sex hormone deficiency (post-cast 1) did not significantly change any of the investigated metabolic parameters compared to pre-cast levels. Ten weeks after castration (post-cast 2) significant insulin resistance, glucose intolerance and hyperglucagonemia was found, and the beta cell function and the disposition index both were decreased.In conclusion, castration-induced sex hormone deficiency in male Göttingen minipigs results in hyperphagia, obesity and disturbed glucose metabolism, which are some of the features typical for the human metabolic syndrome.