The evolution of caste polymorphism in social insects:0 Genetic release followed by diversifying evolution

Caste polymorphism, defined as the presence within a colony of two or more morphologically differentiated individuals of the same sex, is an important character of highly eusocial insects both in the Hymenoptera (ants, bees and wasps) and in the Isoptera (termites), the only two groups in the animal kingdom where highly eusocial species occur. Frequently, caste polymorphism extends beyond mere variations in size (although the extent of variations in size can be in the extreme) and is accompanied by allometric variations in certain body parts. How such polymorphism has evolved and why, in its extreme form, it is essentially restricted to the social insects are questions of obvious interest but without satisfactory answers at the present time. I present a hypothesis entitled ‘genetic release followed by diversifying evolution’, that provides potential answers to these questions. I argue that genetic release followed by diversifying evolution is made possible under a number of circumstances. One of them I propose is when some individuals in a species begin to rely on the indirect component of inclusive fitness while others continue to rely largely on the direct component, as workers and queens in social insects are expected to do. Thus when queens begin to rely on workers for most of the foraging, nest building and brood care, and workers begin to rely increasingly on queens to lay eggs—when queen traits and worker traits do not have to be expressed in the same individual—I postulate the relaxation of stabilizing selection and new spurts of directional selection on both queen-trait genes and worker-trait genes (in contrasting directions) leading to caste polymorphism.     

PEGylated liposomes of anastrozole for long-term treatment of breast cancer: in vitro and in vivo evaluation

The aim of present study was to develop conventional and PEGylated (long circulating), liposomes containing anastrozole (ANS) for effective treatment of breast cancer. ANS is a third-generation non-steroidal aromatase inhibitor of the triazole class used for the treatment of advanced and late-stage breast cancer in post-menopausal women. Under such disease conditions the median duration of therapy should be prolonged until tumor regression ends (>31 months). Liposomes were prepared by the thin film hydration method by using ANS and various lipids such as soyaphosphatidyl choline, cholesterol and methoxy polyethylene glycol distearoyl ethanolamine in different concentration ratios and evaluated for physical characteristics, in vitro drug release and stability. Optimized formulations of liposome were studied for in vitro cytotoxic activity against the BT-549 and MCF-7 cell lines and in vivo behavior in Wistar rats. Preformulation studies, both Fourier transform infrared study and differential scanning calorimetry analysis showed no interaction between the drug and the excipients used in the formulations. The optimized formulations AL-07 and AL-09 liposomes showed encapsulation efficiencies in the range 65.12?±?1.05% to 69.85?±?3.2% with desired mean particle size distribution of 101.1?±?5.9 and 120.2?±?2.8?nm and zeta potentials of ?43.7?±?4.7 and ?62.9?±?3.5 mV. All the optimized formulations followed Higuchi-matrix release kinetics and when plotted in accordance with the Korsemeyer–Peppas method, the n-value 0.5?n?in vitro cytotoxicity studies (p?(0–∞) values when compared to pure drug (p?相似文献   

Lysine acetylation of the Mycobacterium tuberculosis HU protein modulates its DNA binding and genome organization

Nucleoid‐associated protein HU, a conserved protein across eubacteria is necessary for maintaining the nucleoid organization and global regulation of gene expression. Mycobacterium tuberculosis HU (MtHU) is distinct from the other orthologues having 114 amino acid long carboxyl terminal extensions with a high degree of sequence similarity to eukaryotic histones. In this study, we demonstrate that the DNA binding property of MtHU is regulated by posttranslational modifications akin to eukaryotic histones. MtHU purified from M. tuberculosis cells is found to be acetylated on multiple lysine residues unlike the E. coli expressed recombinant protein. Using coimmunoprecipitation assay, we identified Eis as one of the acetyl transferases that interacts with MtHU and modifies it. Although Eis is known to acetylate aminoglycosides, the kinetics of acetylation showed that its protein acetylation activity on MtHU is robust. In vitro Eis modified MtHU at various lysine residues, primarily those located at the carboxyl terminal domain. Acetylation of MtHU caused reduced DNA interaction and alteration in DNA compaction ability of the NAP. Over‐expression of the Eis leads to hyperacetylation of HU and decompaction of genome. These results provide first insights into the modulation of the nucleoid structure by lysine acetylation in bacteria.     

Specific interactions of alcohols and non‐alcohols with a biologically active boronic acid derivative: a spectroscopic study

The photophysical properties of 4‐fluoro‐2‐methoxyphenyl boronic acid (4FMPBA) are characterized using absorption and fluorescence techniques in series of non‐alcohols and alcohols. The results are analyzed using different solvent polarity functions and Kamlet and Catalan's multiple regression approaches. The excited state dipole moment and change in dipole moment are calculated using both the solvatochromic shift method and Reichardt's microscopic solvent polarity parameter . The ground state dipole moment is evaluated using quantum chemical calculations. It is found that general solute–solvent and hydrogen bond interactions are operative in this system. A red shift of ~ 9 nm in the emission spectra is observed with an increase in the solvent polarity, which depicts π→π^* transitions, as well as the possibility of an intramolecular charge transfer (ICT) character in the emitting singlet state of 4FMPBA. The relative quantum yield, radiative and non‐radiative decay constants are calculated in alkanes and alcohols using the single point method. It is found that the quantum yield of the molecule varies from 16.81% to 50.79% with the change in solvent polarity, indicating the dependence of fluorescence on the solvent environment. Copyright © 2015 John Wiley & Sons, Ltd.     

Occurrence and diurnal population fluctuations of the ruminal protozoan Microcetus lappus

A series of experiments with bison and cattle were conducted to obtain information on the relatively uncommon ruminal protozoan Microcetus lappus. Although M. lappus is a holotrich, diurnal changes in concentrations indicate that it follows a cycle unlike most other holotrichs, decreasing shortly after feed is offered and then gradually increasing over time. Concentrations of M. lappus varied widely among animals, exceeding 50% of the total protozoan population in some cattle. In bison, Microcetus concentrations averaged 2% of the protozoan population. Dietary protein and energy levels apparently did not influence Microcetus numbers. The highest concentrations of M. lappus were found in the reticulum, whereas the lowest numbers occurred in the mid-dorsal sac.     

Stemphylium leaf blight of onion

A foliar blight disease of onion (Allium cepa L.) and garlic (Allium sativum L.) hitherto unreported from India has been described from Varanasi, U. P. The infection is confined to the leaves and inflorescence stalks. The conidial stage of the pathogen is more injurious to the plants, whereas the perithecial stage occurs on the inflorescence stalks in isolated locations. The conidiophores and conidia typical of the genus Stemphylium Wallroth are formed during the early development of the disease followed by perithecia predominantly developing on the peduncles. The perithecia were also induced to develop in artificial culture and were identical in diagnostic characters to those from the field. The conidia and ascospores from both host and artificial culture were reciprocally pathogenic to onion and garlic. Morphology of the fruiting structures indicated identity of the pathogen in its conidial stage with Stemphylium vesicarium (Wallroth) Simmons and in the perithecial stage with Pleospora allii (Rabenh.) Ces. and de Not., to which they are referred respectively.     

Growth ofMycobacterium smegmatis in minimal and complete media

The growth patterns ofMycobacterium smegmatis SN2 in a minimal medium and in nutrient broth have been compared. The growth was monitored by absorbancy (Klett readings), colony forming units, wet weight and content of DNA, RNA and protein. During the early part of the growth cycle, the bacteria had higher wet weight and macromolecular content in nutrient broth than in minimal media. During the latter half of the growth cycle however, biosynthesis stopped much earlier in nutrient broth and the bacteria had a much lower content of macromolecules than in the minimal medium. In both the media, a general pattern of completing biosynthesis rapidly in the initial phase and a certain amount of cell division at a later time involving the distribution of preformed macromolecules was seen. The possible adaptive significance of this observation has been discussed.     

Immunochemical relationship between glucoamylases I and II ofAspergillus niger

Rabbit antisera were prepared against the purified glucoamylases I and II ofAspergillus niger. Relationships between the two enzyme forms were investigated by using the antisera in immunodiffusion and immunoinhibition experiments. Both the forms of glucoamylase gave a single continuous precipitin band demonstrating very close structural resemblance. They gave almost identical immunoprecipitation patterns and had the same equivalence points indicating that the two forms ofA. niger gluoamylases were immunologically identical. The enzyme treated with periodate was immunologically identical with the controls and had slightly less enzyme activity but showed greatly reduced stability on storage at 4‡ C.     

Moderation of ruminal fermentation by ciliated protozoa in cattle fed a high-grain diet.

The objective of this study was to assess the influence of ciliated protozoa on ruminal fermentation in cattle fed high-grain diets. Six ruminally cannulated steers fed a corn-based grain diet (85% concentrate plus 15% alfalfa hay) at 12-h intervals were assigned randomly to two groups, ciliate free and faunated, in a crossover design. Defaunation was by ruminal emptying, omasal flushing, and treatment with sodium sulfosuccinate. Two to 3 weeks after defaunation, the ruminal contents of all steers were sampled before the morning feeding (0 h) and at 1, 2, 4, 6, 8, and 12 h after feeding to measure pH, analyze fermentation products, and monitor counts of ciliated protozoa and lactic acid-producing and -fermenting bacterial groups. Total numbers of ciliated protozoa in the faunated steers averaged 4.3 x 10(5)/g, and the protozoa consisted of nine genera. Ciliate-free steers had lower (P less than 0.01) ruminal pHs (pH 5.97) than faunated cattle (pH 6.45); however, the treatment-time interaction was not significant. Ruminal lactate and ammonia concentrations were similar in both groups. The total volatile fatty acid concentration was higher (P less than 0.05) in the ciliate-free steers than in the faunated steers and exhibited a treatment-time interaction (P less than 0.05). The acetate-to-propionate ratio was higher (P less than 0.05) in the faunated group than in the ciliate-free group and showed a treatment-time interaction (P less than 0.05). Total anaerobic bacterial counts were about fourfold higher in the ciliate-free group than in the faunated group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Light-enhanced dark respiration in mesophyll protoplasts from leaves of pea

The respiratory oxygen uptake by mesophyll protoplasts of pea (Pisum sativum cv Arkel) was stimulated up to threefold after 15 minutes of illumination at an intensity of 1250 microeinsteins per square meter per second in the presence of 5 millimolar bicarbonate at 30°C. The extent of light-enhanced dark respiration (LEDR) increased progressively with duration of preillumination. The LEDR exhibited two phases. The initial high rate of respiration decreased in about 10 minutes to a lower steady value similar to that before illumination. The promotion of LEDR by the presence of bicarbonate and inhibition by glyceraldehyde or 3-(3,4-dichlorophenyl)-1,1-dimethylurea suggested that LEDR was dependent on products of photosynthetic carbon assimilation/electron transport. Thus, the photosynthetic products exert a markedly quick influence on dark respiration in mesophyll protoplasts.