Gynandromorphs as indicators of modularity and evolvability in ants

Gynandromorphs, individuals that display a mosaic of male and female tissues or cell populations, have been extensively documented in solitary and social insects for over 100 years. Yet the evolutionary significance of gynandromorphs has remained obscure. Here we describe our discovery of a gynandromorph in the hyperdiverse ant genus Pheidole whose pattern of bilateral head mosaicism occurs repeatedly across a wide range of ant species. Based on our findings, we propose that gynandromorphs and other mosaic forms may provide new insights into the modularity and evolvability of morphological traits.     

A homology model for <Emphasis Type="Italic">Clostridium difficile</Emphasis> methionyl tRNA synthetase: active site analysis and docking interactions

Treatment of C. difficile infection is one of the most difficult biomedical challenges. To develop novel antibacterials, researchers have been targeting bacterial molecular functions that are essential for its growth. The methionyl tRNA synthetase (MetRS) is strictly required for protein biosynthesis and success was reported in developing antibacterials to inhibit this enzyme. The present study was aimed at building and analyzing a homology model for C. difficile MetRS in the context of drug design. A homology model of C. difficile MetRS was constructed using Molecular Operating Environment (MOE) software. A. aeolicus MetRS was the main template while the query zinc binding domain was modeled using T. thermophilus MetRS. The model has been assessed and compared to its main template (Ramachandran, ERRAT and ProSA). The active site of the query protein has been predicted from its sequence using a detailed conservation analysis (ClustalW2). Using MOE software, suitable ligands were docked in the constructed model, including a C. difficile MetRS inhibitor REP3123 and the enzyme natural substrate, and the key active site residues and interactions were identified. These docking studies have validated the active site conformation in the constructed model and identified binding interactions.     

NMR-based metabolomic analysis of wild,greenhouse, and in vitro regenerated shoots of <Emphasis Type="Italic">Cymbopogon schoenanthus</Emphasis> subsp. <Emphasis Type="Italic">proximus</Emphasis> with GC–MS assessment of proximadiol

Cymbopogon schoenanthus subsp. proximus is a wild plant distributed in subtropical and east Africa extending from the north to the southern parts of Egypt. Widely used in folk medicine, it is the source of the diuretic sesquiterpene proximadiol. Nuclear magnetic resonance metabolomic analysis of polar extracts of shoots from wild, greenhouse, somatic embryos, and direct and indirect organogenic in vitro cultures was carried out. Metabolic profiling yielded 39 compounds, of which common metabolites were 15 (38.4%). Unique metabolites were trehalose (2.5%) in the wild plants, 2-hydroxylisobutyrate, galactarate and tyrosine (7.6%) in indirect organogenic shoots. Tartrate was found only in direct regenerated shoots (2.5%). Metabolites identified in greenhouse and embryogenic shoots showed no unique compounds. Multivariate analysis revealed significant differences between all tested shoots. 4-aminobutyrate, alanine, glutamine, glucose, fructose, and sucrose were the most significantly different metabolites. Proximadiol was identified and quantitatively measured from the non-polar extract of different types of shoots using gas chromatography and mass spectrometry (GC–MS). Concentrations ranged from 3.6 ± 0.03 to 198.6 ± 7.2 µg/100 mg dry weight in regenerated shoots from somatic embryogenesis and in wild plant shoots, respectively. Direct organogenesis yielded the highest in vitro concentration (20.3 ± 0.5 µg/100 mg dry weight). This study reported the metabolic profiling of C. schoenanthus polar extract and identified primary metabolites that are unique to the wild type and shoots regenerated from different in vitro cultures. Proximadiol was quantified and the in vitro culture system yielding the highest concentration relative to the wild plant was identified.     

Growth and patterning are evolutionarily dissociated in the vestigial wing discs of workers of the red imported fire ant, Solenopsis invicta

Over the last decade, it has become clear that organismal form is largely determined by developmental and evolutionary changes in the growth and pattern formation of tissues. Yet, there is little known about how these two integrated processes respond to environmental cues or how they evolve relative to one another. Here, we present the discovery of vestigial wing imaginal discs in worker larvae of the red imported fire ant, Solenopsis invicta. These vestigial wing discs are present in all worker larvae, which is uncommon for a species with a large worker size distribution. Furthermore, the growth trajectory of these vestigial discs is distinct from all of the ant species examined to date because they grow at a rate slower than the leg discs. We predicted that the growth trajectory of the vestigial wing discs would be mirrored by evolutionary changes in their patterning. We tested this prediction by examining the expression of three patterning genes, extradenticle, ultrabithorax, and engrailed, known to underlie the wing polyphenism in ants. Surprisingly, the expression patterns of these three genes in the vestigial wing discs was the same as those found in ant species with different worker size distributions and wing disc growth than fire ants. We conclude that growth and patterning are evolutionarily dissociated in the vestigial wing discs of S. invicta because patterning in these discs is conserved, whereas their growth trajectories are not. The evolutionary dissociation of growth and patterning may be an important feature of gene networks that underlie polyphenic traits.     

Effect of different stock types and dietary protein levels on key enzyme activities of glycolysis‐gluconeogenesis,the pentose phosphate pathway and amino acid metabolism in Macrobrachium rosenbergii

A feeding trial was conducted to study the effect of dietary protein (DP) levels on the enzyme activities of different stocks of Macrobrachium rosenbergii juveniles, fed two diets prawn type diets either at optimum (ODP, 32%) or sub‐optimum (SDP, 27%) dietary protein. The activity of key enzymes: glycolysis, gluconeogenesis, amino acid catabolism, pentose phosphate pathway, and energy metabolism was examined on different stocks of M. rosenbergii juveniles in various tissues (muscle, hepatopancreas, and gill). Wild juveniles of M. rosenbergii were collected from the west coast of India, Gujarat (G), Maharashtra (M) and from the east coast of India, Andhra Pradesh (A), and raised in culture ponds of 200 m² at 1 juvenile m^‐2. The experiment was conducted for a period of 60 days. A Visible Implant Elastomer (VIE) Tag was injected into different prawn juveniles’ stocks A, (3.06–3.10 g), M, (0.80–1.01 g) and G (0.90–1.06 g) for the individual identification of each class. All the animals were acclimatized for 7 days before being released into the pond. Each of the two diets, the first with 27% SDP, termed the sub‐optimum level (S), and the second 32% DP, termed the optimum level (O), was fed in triplicate ponds. The weight gain of stocked prawn was significantly higher for G stock (3.03 ± 0.18 g) compared to M stock (2.53 ± 0.25 g) and A stock (1.33 ± 0.10 g). In addition weight gain in ODP was significantly higher (3.05 ± 0.22 g) compared to SDP (2.11 ± 0.17 g). Furthermore, both protein level and stock type had a significant (p ≤ 0.05) effect on the survival rate, specific growth rate, and feed conversion ratio of the prawn. A significant interaction was recorded between metabolic enzyme activities and the variation of dietary protein levels and differences in M. rosenbergii stocks, in which stock “G” and “M” exhibited healthier enzyme physiological status than stock “A”. The findings presented here may conclude that the enzymes quickly respond to dietary protein manipulations of cultured shrimp. The results can be useful in identifying the optimum stock (genotypes) in a given culture condition and subsequently higher production may be achieved.     

Indirect synchronous fluorescence spectroscopy and direct high‐performance thin‐layer chromatographic methods for enantioseperation of zopiclone and determination of chiral‐switching eszopiclone: Evaluation of thermodynamic quantities of chromatographic separation

Economic and enantioselective synchronous fluorescence spectroscopy and high‐performance thin‐layer chromatography methods have been developed and validated as per ICH guidelines for the separation of zopiclone enantiomers using L‐(+)‐tartaric acid as a chiral selector, followed by determination of the chiral‐switching eszopiclone. Synchronous fluorescence spectroscopy was successfully applied for chiral recognition of R & S enantiomers of zopiclone at ?λ = 110 nm based on creating of diastereomeric complexes with 0.06M tartaric acid in an aqueous medium containing 0.2M disodium hydrogen orthophosphate. Synchronous fluorescence intensities of eszopiclone were recorded at 296 nm in concentration range 0.2‐ to 4‐μg/mL eszopiclone. High‐performance thin‐layer chromatography method depends on resolution of zopiclone enantiomers on achiral HPTLC silica‐gel plates using acetonitrile:methanol:water (8:2:0.25, v/v/v) containing L‐(+)‐tartaric acid as a chiral mobile‐phase additive followed by densitometric measurements at 304 nm in concentration range of 1 to 10 μg/band of eszopiclone. The effect of chiral‐selector concentration, pH, and temperature on the resolution have been studied and optimized for the proposed methods. The cited procedures were successfully applied to determine eszopiclone in commercial tablets of pure and racemic forms. Enantiomeric excess was evaluated using optical purity test and integrated peak area to describe the enantiomeric ratio. Thermodynamics of chromatographic separation, enthalpy, and entropy were evaluated using the Van't Hoff equation. The proposed methods were found to be selective for identification and determination of the eutomer in drug substances and products.     

Citric acid production by a novel Aspergillus niger isolate: I. Mutagenesis and cost reduction studies

Ultraviolet-irradiation (UV), ethyl methane sulfonate (EMS) and acridine orange (AO) were used to induce citric acid overproduction mutations in Aspergillus niger UMIP 2564. Among 15, eight of the mutant derivatives, were improved with respect to citric acid production from sucrose in batch cultures. Maximum product yield (60.25%) was recorded by W5, a stable UV mutant, with approximately 3.2-fold increase when compared to the parental wild type strain. In terms of the kinetic parameters for batch fermentation processes, the mutation doubled the specific substrate uptake rate and achieved 4.5- and 7.5-fold improvements in citric acid productivity and specific productivity, respectively. For reduction of the fermentation medium cost, corn steep liquor and calcium phosphate pre-treated beet molasses were successfully used as substituents of nitrogen and carbon sources in the growth medium, respectively. These medium substitutions resulted in a W5 citric acid fermentation culture with a product yield of 74.56%.