D-amino acids in the cell pool of bacteria

About 30 different bacterial species were tested for the possible presence of freed-amino acids in their cell pool. Gram-positive bacteria particularly the species of the genusBacillus have a fairly large pool of freely extractabled-amino acids. Varied quantities of freed-amino acids were detected inBacillus subtilis B₃,Bacillus subtilis Marburg,Bacillus licheniformis, Bacillus brevis, Bacillus stearothermophilus, Lactobacillus fermenti, Lactobacillus delbrueckii, Staphylococcus aureus andClostridium acetobutylicum. The individual components ofd-amino acids were identified in 5Bacillus species referred to above,d-alanine is the major component; the otherd-amino acids identified are aspartic acid, glutamic acid, histidine, leucines, proline, serine and tyrosine. Thed-amino acid pool size inBacillus subtilis B₃ varies with different culture conditions. The pool size is maximum when growth temperature is 30°C and it fluctuates with change in pH of the medium. The maximum quantity ofd-amino acids could be recovered when the culture was at mid log phase. O₂ supply to the medium has little effect ond-amino acid pool size. The starvation of cells leads to depletion of thed-amino acid pool which is exhausted almost completely within 4 hours by incubation in nutrient-free medium.     

The effects of ecological and genetic neighbourhood size on the evolution of two competing species

Summary Individual-based simulations were conducted to examine the effect of a small ecological neighbourhood (an area in which ecological processes such as density-dependent factors operate) and the genetic neighbourhood size (the size of an area from which the parents may be assumed to be drawn at random) on the coevolution of two competing species. For the simulations, individuals of two consumer species compete for two types of food organisms. Different genotypes (one locus and two alleles) have different efficiencies of food acquisition for different food types. Individual consumer organisms search for food within their home ranges and reproduce depending on the amount of food eaten. The dispersal distance of the offspring follows a normal distribution with a zero mean and _d standard deviation. Simulations were conducted by varying the home range size, mating area (area from where individuals choose their mates), standard deviation of dispersal distance, food generation time, the reproductive rates of food populations and the sizes and number of independent food populations. Food organisms reproduce either within one population or independently within 16 spatially divided populations. For all the simulations, competitive exclusion was the most frequent outcome and character displacement was the least frequent outcome. Through a 200-generation simulation, the two consumer species could co-exist longer and maintain a polymorphic resource use longer when the home range and mating size were small in 16 spatially divided populations than when random mating and homogeneous interaction occurred within a community (perfect mixing population). For perfect mixing populations, the frequency of character displacement increased as the food generation time became short and the reproductive rates of food decreased. It follows from the results that the sizes of the genetic and ecological neighbourhoods and the mode of resource dynamics can affect the evolution of two competing species.     

Impact of worker longevity and other endogenous factors on colony size in the fire ant, <Emphasis Type="Italic">Solenopsis invicta</Emphasis>

Central to the survival and reproduction of social insect queens is the size of colonies at maturity. The influence of exogenous factors such as predation, food abundance, and seasonal changes in temperature on colony size are well studied. Less well studied are endogenous life-history factors such as a queen’s fertility and lifespan, duration of worker development from egg to adult and worker lifespan. Endogenous factors regulating the rate of colony growth and colony size were simulated using the fire ant, Solenopsis invicta. Assuming ideal environmental conditions of no predation, abundant food and uniform temperature, the simulation showed unequivocally that colony size is determined by two endogenous factors: a queen’s egg-laying rate (R _q) and worker longevity (L _w) (Colony size = R _q × L _w). Thus, we are left with an unanswered question: if worker longevity contributes directly to colony size, why is the lifespan of workers so short—in most cases, a small fraction of a queen’s lifespan?     

The Water and Nonelectrolyte Permeability Induced in Thin Lipid Membranes by the Polyene Antibiotics Nystatin and Amphotericin B

Nystatin and amphotericin B increase the permeability of thin (<100 A) lipid membranes to ions, water, and nonelectrolytes. Water and nonelectrolyte permeability increase linearly with membrane conductance (i.e., ion permeability). In the unmodified membrane, the osmotic permeability coefficient, P_f, is equal to the tagged water permeability coefficient, (P_d)_w; in the nystatin- or amphotericin B-treated membrane, P_f/(P_d)_w ≈ 3. The unmodified membrane is virtually impermeable to small hydrophilic solutes, such as urea, ethylene glycol, and glycerol; the nystatin- or amphotericin B-treated membrane displays a graded permeability to these solutes on the basis of size. This graded permeability is manifest both in the tracer permeabilities, P_d, and in the reflection coefficients, σ (Table I). The "cutoff" in permeability occurs with molecules about the size of glucose (Stokes-Einstein radius 4 A). We conclude that nystatin and amphotericin B create aqueous pores in thin lipid membranes; the effective radius of these pores is approximately 4 A. There is a marked similarity between the permeability of a nystatin- or amphotericin B-treated membrane to water and small hydrophilic solutes and the permeability of the human red cell membrane to these same molecules.     

Central place foraging by swallows (Hirundinidae): The question of load size

Some predictions of Orians & Pearson's (1979) models for central place foragers (CPF) were tested with three species of swellows (Hirundinidae). House martins (Delichon urbica) and sand martins (Riparia riparia) brought larger food loads to the nest mainly when foraging distances were great, whereas swallows (Hirundo rustica) gathered large loads when food was plentiful. For all three species the outcome conformed qualitatively with the predictions of the CPF models. Overall, house martins were the most sensitive to travel time effects, but in a quantitative test the predicted load size was 20–40% less than the observed size for a range of realistic travel times. Additional models are presented which emphasize the significance of foraging techniques and foraging costs for optimal load size in multiple prey loaders.     

Invertebrate predation predicts variation in an autotomy-related trait in larval damselfly

Autotomy, the discarding of a prey appendage grasped by a predator, may evolve when the benefits of immediate survival outweigh the costs of appendage loss. In larval damselflies, joints connecting lamellae to the abdomen vary in size and shape within and among taxa suggesting that they may evolve under selection by invertebrate predators, such as dragonfly larvae. Assuming that joint width is proportional to the force required for autotomy, we tested if invertebrate predation favours smaller lamellar joints for autotomy or larger joints for structural support of lamellae for swimming. We compared the maximum joint widths of larval Lestes and Enallagma among ponds that varied in risk of invertebrate predation. Relative predation risk estimated as the frequency of regenerated lamellae within ponds was weakly and positively related to the relative abundance of larval dragonflies. The allometry of lamellar joint size decreased with increasing risk of invertebrate predation across ponds after controlling for variation in body size in Lestes congener but not in Enallagma species. Both species of Lestes had larger joint sizes than the five species of Enallagma, suggesting that the ancestral divergence of lamellar joints between these genera may influence contemporary responses to invertebrate predation.     

Stability of Emulsions Using a New Natural Emulsifier: Sugar Beet Extract <Emphasis Type="Italic">(Beta vulgaris L.)</Emphasis>

This study describes the influence of environmental stresses on the stability of emulsions prepared by a natural sugar beet extract (Beta vulgaris L.). The emulsion stabilizing performance was compared to that of Quillaja extract, which is widely used within the food and beverage industry as natural surfactant. We investigated the influence of pH, ionic strength, heating and freeze-thawing on the mean particle size, ζ-potential and microstructure of oil-in-water emulsions (10% w/w oil, 0.75% w/w emulsifier). The emulsions stabilized by the anionic sugar beet extract were stable at pH 5–8 and against thermal treatments up to 60 °C. However, the prepared emulsions were unstable at acidic (pH 2–4) and basic pH conditions (pH 9), at high temperature (>60 °C), and at salt additions (> 0.1 M NaCl / CaCl₂). Moreover, they also phase separated upon freeze-thawing. Our results show that sugar beet extract is capable of stabilizing emulsions and may therefore be suitable as natural emulsifier for selected applications in the food and beverage industry.     

The effect of encapsulated fine grain sediment and test morphology on the resistance of planktonic foraminifera to dissolution

The tests of planktonic foraminifera recovered from deep-sea sediment are commonly observed to encapsulate fine grain carbonate sediment within their chambers. In sediment below the lysocline, the interstitial water within the chambers may not be as corrosive as the seawater in contact with the outer surface of the test due to slow continuous dissolution of the encapsulated carbonate. As a consequence, the pore walls of the foram dissolve more slowly than the outer surface of the test.Using published dissolution rate measurements for foraminifera and deep-sea sediment, the effect of diffusional reduction of pore wall dissolution was quantitatively estimated with a one-dimensional model for the steady state condition where diffusional flux out of the foraminifer's pores is balanced by the dissolution flux from the encapsulated fines and pore walls. The diffusional effect is found to principally depend on the structural parametric ratioT_wd_T/f, whereT_w is the wall thickness,d_T the test diameter andf is the test porosity. In the case of adult planktonic foraminifera, the ratio of the pore wall to outer surface dissolution flux is predicted to vary between 60% for the thin-walled porous species and 30% for thick-walled tests.Incorporation of the predicted pore to outer surface flux ratios into the morphologic index equation of Adelseck (1978) results in a very good prediction (73% of the variation) of the solution index of Berger (1975) obtained from ranking species counts from core tops. A simple empirical equation which may be useful for prediction of the resistance of extinct microfossils was found as follows:

$R=\frac{T_w}{\lambda \{1+[A_w/(A_s?A_p)][.74?.27log?(T_w{d}_T/f)]\}}$

is the measured ratio of pore wall area to outer surface of the test, andT_wd_T/f is in units of 10⁴ μm².     

Short-term movements and strong dependence on figs of binturongs (<Emphasis Type="Italic">Arctictis binturong</Emphasis>) in Bornean rainforests

We evaluated short-term movements of three radio-collared binturongs in relation to food distribution in Bornean rainforests, in addition to the basic ecological information on their home-range size and diet. Mean 95% fixed kernel and 95% MCP home-range size were 4.24?±?0.79 km² and 1.54?±?0.89 km², respectively (mean ± SD). We recorded 13 fig Ficus species and four non-fig species as their foods. Fig trees accounted for 87.5% of the feeding sites of the three collared binturongs, and 87.9% including uncollared individuals. Our results suggested that binturongs’ short-term movements were strongly affected by food distribution, especially figs. They feed on various fig species and may remember the location and fruiting periods of fig trees. They may use the biggest fig species, F. punctata, as a fallback food when other foods are scarce. Although this is the first systematic study to describe movement and feeding habits of binturongs, further studies are needed to understand their ecology so that proper measures can be designed for their conservation.     

Impacts on Micro- and Macro-Structure of Thermally Stabilised Whey Protein-Pectin Complexes: A Fluorescence Approach

Stability of whey protein-pectin complexes is an essential criterion for their application in different food matrices. The impact of process parameters on micro- and macro-structural characteristics of thermally stabilised whey protein-pectin complexes was investigated using fluorescence spectroscopy, ζ-potential measurements, dynamic light scattering and phase separation. Complexes prepared from whey protein isolate (WPI) and pectins with different degrees of esterification (HMP, LMP) were generated at different biopolymer concentrations (WPI + pectin: 5.0 % + 1.0 %, c _{h i g h} ; 2.75 % + 0.55 %, c _{m e d} ; 0.5 % + 0.1 %, c _{l o w} ), heating temperatures (80-90^°C) and pH levels (6.1-4.0). Micro- and macro-structural characteristics of the complexes depended on concentration level and degree of esterification, with complexes being more sensitive towards environmental changes at c _{l o w} than at c _{m e d} and c _{h i g h} . WPI-LMP complexes exhibited sizes <1 μm suitable for micro-encapsulation, whereas WPI-HMP complexes at c _{m e d} achieved sizes from 1-10 μm and at c _{h i g h} from 10-200 μm underlining their potential as fat-replacers and structuring agents, respectively. Slopes and intercepts derived from intensity ratios of fluorescence spectra gave insights into the state of unfolding of β-lactoglobulin within the complexes and thus about the protective effect of pectin addition.     

Defective gut function in drop-dead mutant Drosophila

Mutation of the gene drop-dead (drd) causes adult Drosophila to die within 2 weeks of eclosion and is associated with reduced rates of defecation and increased volumes of crop contents. In the current study, we demonstrate that flies carrying the strong allele drdlwf display a reduction in the transfer of ingested food from the crop to the midgut, as measured both as a change in the steady-state distribution of food within the gut and also in the rates of crop emptying and midgut filling following a single meal. Mutant flies have abnormal triglyceride (TG) and glycogen stores over the first 4 days post-eclosion, consistent with their inability to move food into the midgut for digestion and nutrient absorption. However, the lifespan of mutants was dependent upon food presence and quality, suggesting that at least some individual flies were able to digest some food. Finally, spontaneous motility of the crop was abnormal in drdlwf flies, with the crops of mutant flies contracting significantly more rapidly than those of heterozygous controls. We therefore hypothesize that mutation of drd causes a structural or regulatory defect that inhibits the entry of food into the midgut.     

Effects of starvation on larval growth, survival, and metamorphosis of Manila clam Ruditapes philippinarum

The effects of starvation on larval growth, survival, and metamorphosis of Manila clam Ruditapes philippinarum at the temperature of 19.6–21.6 °C, the salinity of 34‰ and pH of 8.0 were investigated from May 18 to July 18, 2006. In this study, the early, middle and late umbo-veliger larvae with the shell lengths of 100, 140, and 190 μm were subject to temporary food deprivation for up to 4.5, 20, and 25d at 0.5, 4, 5d intervals, followed by refeeding for the remaining of a 24, 20, 25d period, respectively. The results suggested that the larvae should have shown considerable tolerance to starvation due to their endogenous and exterior nutrition material, for larvae and time to the point-of-no-return (PNR: the threshold point during starvation after which larvae could no longer metamorphose even if food is provided) were calculated to be 4.25, 17.54, and 22.17d. As the starvation period prolonged, the mean shell length of larvae starved got close to constants at 1.5, 4, and 15d after starvation, which were different for larvae at different stages when starvation began, survival of larvae decreased, and was lower in treatments starved earlier in development than those starved later, for the early, middle and late umbo-veliger larvae, after 4.5, 20 and 25d of starvation period, few larvaes were alive. After starvation period, the alive larvaes were able to metamorphose and had a capability of compensatory growth when refeeding was given. Starvation not only affected metamorphosis rate, but also caused the delay in the time to metamorphosis and the decrease in the metamorphosed sizes. For example, for the continuously-fed larvae, duration to metamorphosis was 20.7d, for larvae with a size of 100-μm starved for up to 4d, larvae with a size of 140-μm starved for up to 16d, larvae with a size of 190-μm starved for up to 20d, duration to metamorphosis were 29.7, 31.7, and 37.7d, the delay in duration to metamorphosis were 9, 11, and 17d, respectively. Furthermore, importance of nutrition material for maintaining larval survival during starvation and the compensatory growth on larvae at the same feeding time were discussed.     

Phylogenomics of the reproductive parasite Wolbachia pipientis wMel: a streamlined genome overrun by mobile genetic elements

The complete sequence of the 1,267,782 bp genome of Wolbachia pipientis wMel, an obligate intracellular bacteria of Drosophila melanogaster, has been determined. Wolbachia, which are found in a variety of invertebrate species, are of great interest due to their diverse interactions with different hosts, which range from many forms of reproductive parasitism to mutualistic symbioses. Analysis of the wMel genome, in particular phylogenomic comparisons with other intracellular bacteria, has revealed many insights into the biology and evolution of wMel and Wolbachia in general. For example, the wMel genome is unique among sequenced obligate intracellular species in both being highly streamlined and containing very high levels of repetitive DNA and mobile DNA elements. This observation, coupled with multiple evolutionary reconstructions, suggests that natural selection is somewhat inefficient in wMel, most likely owing to the occurrence of repeated population bottlenecks. Genome analysis predicts many metabolic differences with the closely related Rickettsia species, including the presence of intact glycolysis and purine synthesis, which may compensate for an inability to obtain ATP directly from its host, as Rickettsia can. Other discoveries include the apparent inability of wMel to synthesize lipopolysaccharide and the presence of the most genes encoding proteins with ankyrin repeat domains of any prokaryotic genome yet sequenced. Despite the ability of wMel to infect the germline of its host, we find no evidence for either recent lateral gene transfer between wMel and D. melanogaster or older transfers between Wolbachia and any host. Evolutionary analysis further supports the hypothesis that mitochondria share a common ancestor with the α-Proteobacteria, but shows little support for the grouping of mitochondria with species in the order Rickettsiales. With the availability of the complete genomes of both species and excellent genetic tools for the host, the wMel–D. melanogaster symbiosis is now an ideal system for studying the biology and evolution of Wolbachia infections.     

ELECTRON MICROSCOPE STUDIES ON THE HAEMOGLOBIN MOLECULES

Haemoglobin molecules isolated from normal human subjects have been directly micrographed under the electron microscope following in general Hall's technique. The average height (h) and the widths along (w₁₁) and perpendicular (w) to the shadow direction of the molecules have been measured as 56.5 ± 6.6 A, 122.7 ± 15 A, and 120.9 ± 20 A, respectively. The exaggeration in the molecular widths due to the deposition of metal cap ranges between 60 to 70 A. The probable resolution of the substructure of the molecule, e.g., presence of "holes" and dimples, in the present electron microscopic evidence has been discussed. The electron microscopic results on the size of the individual haemoglobin molecules are in satisfactory agreement with the recent x-ray diffraction model of Perutz and his associates for horse haemoglobin.     

Multilevel Selection 4: Modeling the Relationship of Indirect Genetic Effects and Group Size

Indirect genetic effects (IGE) occur when individual trait values depend on genes in others. With IGEs, heritable variance and response to selection depend on the relationship of IGEs and group size. Here I propose a model for this relationship, which can be implemented in standard restricted maximum likelihood software.SOCIAL interactions among individuals are abundant in life (Frank 2007). Trait values of individuals may, therefore, depend on genes in other individuals, a phenomenon known as indirect genetic effects (IGE; Wolf et al. 1998) or associative effects (Griffing 1967; Muir 2005). IGEs may have drastic effects on the rate and direction of response to selection. Moreover, with IGEs, heritable variance and response to selection depend on the size of the interaction group, hereafter denoted group size (Griffing 1967; Bijma et al. 2007; McGlothlin et al. 2010). The magnitude of the IGEs themselves, however, may also depend on group size, because interactions between a specific pair of individuals are probably less intense in larger groups (Arango et al. 2005). The relationship between the magnitude of IGEs and group size is relevant because it affects the dynamics of response to selection, heritable variation, and group size, determining, e.g., whether or not selection is more effective with larger groups. Moreover, a model for this relationship is required to estimate IGEs from data containing varying group sizes. Hadfield and Wilson (2007) proposed a model for the relationship between IGEs and group size. Here I present an alternative.With IGEs, the trait value of focal individual i is the sum of a direct effect rooted in the focal individual itself, P_D,i, and the sum of the indirect effects, P_S,j, of each of its n − 1 group mates j,(1)where A and E represent the heritable and nonheritable component of the full direct and indirect effect, respectively, and n denotes group size (Griffing 1967). When IGEs are independent of group size, total heritable variance in the trait equals (Bijma et al. 2007)(2)For a fixed becomes very large with large groups. This is unrealistic because an individual''s IGE on a single recipient probably becomes smaller in larger groups. The decrease of IGEs with group size, referred to as dilution here, will depend on the trait of interest. With competition for a finite amount of feed per group, for example, an individual consuming 1 kg has an average indirect effect of P_S,i = −1/(n − 1) on feed intake of each of its group mates. Hence, the indirect effect is inversely proportional to the number of group mates, indicating full dilution. The other extreme of no dilution may be illustrated by alarm-calling behavior, where an individual may warn all its group mates when a predator appears, irrespective of group size. Here the indirect effect each group mate receives is independent of group size, indicating no dilution. The degree of dilution is an empirical issue, which may be trait and population specific, and needs to be estimated.Here I propose to model dilution of indirect effects as(3)where P_S,i,n is the indirect effect of individual i in a group of n members, P_S,i,2 the indirect effect of i in a group of two members, and d the degree of dilution. With no dilution, d = 0, indirect effects do not depend on group size, P_S,i,n = P_S,i,2, as with alarm-calling behavior. With full dilution, d = 1, indirect effects are inversely proportional to the number of group mates, P_S,i,n = P_S,i,2/(n − 1), as with competition for a finite amount of feed. Equation 3 is an extension of the model of Arango et al. (2005), who used d = 1.Assuming that IGEs are diluted in the same manner as the full indirect effect, the indirect genetic variance for groups of n members equals(4)and total heritable variance equals(5)Hence, for σ_ADS = 0, total heritable variance increases with group size as long as dilution is incomplete (d < 1). Total heritable variance is independent of group size with full dilution (d = 1). Phenotypic variance also depends on group size. With unrelated group members,(6)which increases with group size for d < 0.5, is independent of group size for d = 0.5, and decreases with group size for d > 0.5.The degree of dilution can be estimated from data containing variation in group size, by using a mixed model with restricted maximum likelihood and evaluating the likelihood for different fixed values of d (Arango et al. 2005; Canario et al. 2010). With Equation 3, however, the estimated genetic (co)variances and breeding values for indirect effect refer to a group size of two individuals, which is inconvenient when actual group size differs considerably. Estimates of A_S, , and σ_ADS referring to the average group size may be obtained from the following mixed model,(7)where z is a vector of observations, Xb are the usual fixed effects, Z_Da_D are the direct genetic effects, Z_gg are random group effects, and e is a vector of residuals. The is a vector of IGEs referring to the average group size, and Z_S(d) is the incidence matrix for IGEs, which depends on the degree of dilution; dilution being specified relative to the average group size. Elements of Z_S(d) are(8)where denotes average group size. This model is equivalent to Equation 3, but yields estimates of genetic parameters and breeding values referring to the average group size because for . When the magnitude of IGEs depends on group size, the group and residual variance in Equation 7 will depend on group size:(9a)(9b)Hence, to obtain unbiased estimates of the genetic parameters and d, it may be required to fit a separate group and residual variance for each group size.To account for the relationship between IGEs and group size, Hadfield and Wilson (2007; HW07) proposed including an additional IGE. In their model, an individual''s full IGE is the sum of an effect independent of group size, and an effect regressed by the reciprocal of the number of group mates,(10)There are a number of differences between both models. First, Equation 3 specifies the relationship between the magnitude of IGEs and group size on the population level, which is sufficient to remedy the problem of increasing variance with group size. The HW07 model, in contrast, specifies the relationship between the magnitude of IGEs and group size on the individual level. In the HW07 model, the absolute value of (1/(n − 1))A_SR,_i decreases with group size, while A_S,i is constant. Consequently, the relationship between an individual''s full IGE and group size depends on the relative magnitudes of its A_S,i and A_SR,_i; the IGEs of individuals with greater |A_SR| show greater change when group size varies. This alters the IGE ranking of individuals when group size varies. The HW07 model, therefore, not only scales IGEs with group size, but also allows for IGE-by-group-size interaction, whereas Equation 3 scales IGEs of all individuals in the same way. Second, the interpretation of the genetic parameters differs between both models. In the HW07 model, lim_n→∞ A_S,i,HW07 = A_S,i, meaning that Var(A_S) represents the variance in IGEs when group size is infinite. With Equation 3 or 7, in contrast, refers to groups of two individuals or to the average group size. Third, in the HW07 model, the dilution of IGEs with group size is implicitly incorporated in the magnitudes of Var(A_S) and Var(A_SR), greater Var(A_SR) implying greater dilution. Equation 3, in contrast, has a single parameter for the degree of dilution, expressed on a 0–1 scale. Finally, implementing the HW07 model involves estimating three additional covariance parameters, Var(A_SR), Cov(A_D, A_SR), and Cov(A_S, A_SR), whereas implementing the model proposed here involves estimating a single additional fixed effect, which is simpler. In conclusion, the HW07 model has greater flexibility than the model proposed here, but is also more difficult to implement and interpret.     

Pharmacokinetic Evaluation of Improved Oral Bioavailability of Valsartan: Proliposomes <Emphasis Type="Italic">Versus</Emphasis> Self-Nanoemulsifying Drug Delivery System

The objective of this study was to develop proliposomes and self-nanoemulsifying drug delivery system (SNEDDS) for a poorly bioavailable drug, valsartan, and to compare their in vivo pharmacokinetics. Proliposomes were prepared by thin-film hydration method using different lipids such as soy phosphatidylcholine (SPC), hydrogenated soy phosphatidylcholine (HSPC), distearyl phosphatidylcholine (DSPC), dimyristoylphosphatidylcholine (DMPC), and dimyristoyl phosphatidylglycerol sodium (DMPG) and cholesterol in various ratios. SNEDDS formulations were prepared using varying concentrations of capmul MCM, labrafil M 2125, and Tween 80. Both proliposomes and SNEDDS were evaluated for particle size, zeta potential, in vitro drug release, in vitro permeability, and in vivo pharmacokinetics. In vitro drug release was carried out in purified water and 0.1 N HCl using USP type II dissolution apparatus. In vitro drug permeation was studied using parallel artificial membrane permeation assay (PAMPA) and everted rat intestinal permeation techniques. Among the formulations, the proliposomes with drug/DMPG/cholesterol in the ratio of 1:1:0.5 and SNEDDS with capmul MCM (16.0% w/w), labrafil M 2125 (64.0% w/w), and Tween 80 (18.0% w/w) showed the desired particle size and zeta potential. Enhanced drug release was observed with proliposomes and SNEDDS as compared to pure valsartan. Valsartan permeability across PAMPA and everted rat intestinal permeation models was significantly higher with proliposomes and SNEDDS. Following single oral administration of proliposomes and SNEDDS, a relative bioavailability of 202.36 and 196.87%, respectively, was achieved compared to pure valsartan suspension. The study results indicated that both proliposomes and SNEDDS formulations are comparable in improving the oral bioavailability of valsartan.     

Sibling Cannibalism of Young Red Drum, Sciaenops ocellatus, in Relation to Size Disparity and Metabolic Rates

Cannibalism is a leading cause of young mortality in the red drum, Sciaenops ocellatus, culture, and size disparity is its primary causative factor. Cannibalism did not occur in young fish, graded by a difference of 0.5cm from 2.0 to 4.5cm in total length. There was a shift in the size distribution from unimodal (normal) when there was no cannibalism, to bimodal or trimodal when cannibalism occurred. The results suggested that the wider was the size disparity, the greater was the sibling cannibalism. Size disparity increased with growth and in turn with sibling cannibalism, which became insignificant when the young grew to a size of about 6cm. We present threshold levels of size disparity among siblings to prevent mutual cannibalism. We hypothesize that through sibling cannibalism a hierarchy may evolve in a red drum cohort, at which a stable population will form.     

Estimation of pack density in grey wolf (<Emphasis Type="Italic">Canis lupus</Emphasis>) by applying spatially explicit capture-recapture models to camera trap data supported by genetic monitoring

Background

Density estimation is a key issue in wildlife management but is particularly challenging and labour-intensive for elusive species. Recently developed approaches based on remotely collected data and capture-recapture models, though representing a valid alternative to more traditional methods, have found little application to species with limited morphological variation. We implemented a camera trap capture-recapture study to survey wolf packs in a 560-km² area of Central Italy. Individual recognition of focal animals (alpha) in the packs was possible by relying on morphological and behavioural traits and was validated by non-invasive genotyping and inter-observer agreement tests. Two types (Bayesian and likelihood-based) of spatially explicit capture-recapture (SCR) models were fitted on wolf pack capture histories, thus obtaining an estimation of pack density in the area.

Results

In two sessions of camera trapping surveys (2014 and 2015), we detected a maximum of 12 wolf packs. A Bayesian model implementing a half-normal detection function without a trap-specific response provided the most robust result, corresponding to a density of 1.21?±?0.27 packs/100 km² in 2015. Average pack size varied from 3.40 (summer 2014, excluding pups and lone-transient wolves) to 4.17 (late winter-spring 2015, excluding lone-transient wolves).

Conclusions

We applied for the first time a camera-based SCR approach in wolves, providing the first robust estimate of wolf pack density for an area of Italy. We showed that this method is applicable to wolves under the following conditions: i) the existence of sufficient phenotypic/behavioural variation and the recognition of focal individuals (i.e. alpha, verified by non-invasive genotyping); ii) the investigated area is sufficiently large to include a minimum number of packs (ideally 10); iii) a pilot study is carried out to pursue an adequate sampling design and to train operators on individual wolf recognition. We believe that replicating this approach in other areas can allow for an assessment of density variation across the wolf range and would provide a reliable reference parameter for ecological studies.