Bacterial magnetosomes as an efficient gene delivery platform for cancer theranostics

Background

Gene therapy has gained an increasing interest in its anti-tumor efficiency. However, numerous efforts are required to promote them to clinics. In this study, a novel and efficient delivery platform based on bacterial magnetosomes (BMs) were developed, and the efficiency of BMs in delivering small interfering ribonucleic acid (siRNA) as well as antiproliferative effects in vitro were investigated.

Results

Initially, we optimized the nitrogen/phosphate ratio and the BMs/siRNA mass ratio as 20 and 1:2, respectively, to prepare the BMs–PEI–siRNA composites. Furthermore, the prepared nanoconjugates were systematically characterized. The dynamic light scattering measurements indicated that the particle size and the zeta potential of BMs–PEI–siRNA are 196.5 nm and 49.5 ± 3.77 mV, respectively, which are optimum for cell internalization. Moreover, the confocal laser scanning microscope observations showed that these composites were at a proximity to the nucleus and led to an effective silencing effect. BMs–PEI–siRNA composites efficiently inhibited the growth of HeLa cells in a dose-as well as time-dependent manner. Eventually, a dual stain assay using acridine orange/ethidium bromide, revealed that these nanocomposites induced late apoptosis in cancer cells.

Conclusions

A novel and efficient gene delivery system based on BMs was successfully produced for cancer therapy, and these innovative carriers will potentially find widespread applications in the pharmaceutical field.

     

Aspergillus biofilms: clinical and industrial significance

The biofilm phenotype is an increasingly important concept in mycological research. Recently, there has been a developing interest in whether Aspergillus species are truly able to form biofilms or not. Industrial mycologists have long been aware of biofilms and their benefit in fermentation processes, whereas clinically their role is uncertain. This review provides an update on the impact that Aspergillus biofilms have medically and industrially, and will discuss biofilm development, and our current understanding of its molecular basis. The role of exopolymeric substance and how this substance relates to antimicrobial recalcitrance will also be discussed.     

Influence of carbon-dioxide on the growth of Spirulina sp. (MCRC-A0003) isolated from Muttukadu backwaters,South India

Growth of Spirulina sp. (MCRC-A0003), a cyanobacterium, was evaluated under different concentrations of carbon-dioxide (CO₂) (4–50 %) in a closed glass photobioreactor. Although significant CO₂ utilization by the cyanobacterial strain was observed up to 50 % concentration, complete utilization was observed only at 4, 10 and 20 % concentrations on 3rd, 6th and 8th day respectively. However, considerable reduction was witnessed in reactors containing 30–50 % CO₂ only between 6th and 9th day. A corresponding increase in the biomass and primary metabolites like chlorophyll-a, carbohydrate and protein were observed. Biomass productivity of Spirulina in reactors sparged with 4, 10 and 20 % CO₂ were 13.7, 43 and 44 % more than that in control reactor without CO₂. While CO₂ increased the levels of primary metabolites in the cyanobacterial cells, it was quite prominent in 10 % CO₂ concentration with the chlorophyll-a, carbohydrate and protein contents were 64, 183 and 626 mg g^?1 respectively. While 10 and 6.6 % increase were noticed in chlorophyll-a and protein, 17 % increase in carbohydrate levels was observed in Spirulina cells, which could be attributed to the conversion of CO₂ to carbohydrate by the cyanobacterium.     

Characterization of inosine–uridine nucleoside hydrolase (RihC) from Escherichia coli

A non-specific nucleoside hydrolase from Escherichia coli (RihC) has been cloned, overexpressed, and purified to greater than 95% homogeneity. Size exclusion chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis show that the protein exists as a homodimer. The enzyme showed significant activity against the standard ribonucleosides with uridine, xanthosine, and inosine having the greatest activity. The Michaelis constants were relatively constant for uridine, cytidine, inosine, adenosine, xanthosine, and ribothymidine at approximately 480 μM. No activity was exhibited against 2′-OH and 3′-OH deoxynucleosides. Nucleosides in which additional groups have been added to the exocyclic N6 amino group also exhibited no activity. Nucleosides lacking the 5′-OH group or with the 2′-OH group in the arabino configuration exhibited greatly reduced activity. Purine nucleosides and pyrimidine nucleosides in which the N7 or N3 nitrogens respectively were replaced with carbon also had no activity.     

Management of Erectile Dysfunction in the Hypogonadal Man: A Case-Based Review

Erectile dysfunction (ED) has emerged as an important marker of cardiovascular and overall health, independent of other known conventional risk factors. ED often precedes coronary artery disease in half of affected subjects, and could indicate the presence of cardiovascular pathology. The pathophysiology and role of androgens in sexual function are described, along with the relevant literature on the effects of aging in erectile and gonadal function. The concept of testosterone supplementation (TST) in men with ED is reviewed. The authors utilize clinical vignettes to discuss the appropriate management of two clinical cases of men at different life stages who have ED in the setting of hypogonadism and propose a treatment algorithm. In patients of all ages, proper identification of the underlying pathophysiology of decreased libido and erectile function is paramount in choosing between the use of TST, phosphodiesterase type 5 inhibitors, or both, in the management of these disorders.Key words: Erectile dysfunction, Testosterone supplementation, Hypogonadism, Phosphodiesterase type 5 inhibitorsErectile dysfunction (ED) has emerged as an important marker of cardiovascular and overall health, independent of other known conventional risk factors. Because ED often precedes coronary artery disease (CAD) in half of affected subjects, it may be considered a harbinger of indolent cardiovascular pathology.^1,2 The modulation of erectile function by testosterone is well known,^3,4 and in men with both hypogonadism and ED a treatment strategy necessitating management of both conditions is required.Phosphodiesterase type 5 inhibitors (PDE5i) and testosterone supplementation therapy (TST) are established treatment strategies for ED and hypogonadism, respectively. Using a PDE5i in combination with TST has the potential for improving efficacy in men with concurrent ED and hypogonadism compared with the use of either agent alone. However, in light of the recent evidence associating testosterone with cardiovascular risk in elderly men,^5,6 TST should be used judiciously in the management of ED in older men.     

New synthesis of 2β-hydroxy-19-oxoandrost-4-ene-3,17-dione and its 2β-O analog

Treatment of 19-[oxygenated]-androst-4-ene-3,17-dione with Mn(AcO)₃ and ClCH₂COOH in benzene gave epimeric mixtures of the corresponding 2ξ-chloroacetates and 2ξ-acetates. The products were processed to give the title compound. For the synthesis of the 2-¹⁸O analog, ClCH₂C¹⁸OOH was used, which was prepared from ClCH₂COCl.     

Triterpenoids and coumarins from the leaves of calophyllum cordato-oblongum

The hot light petrol extractives of the leaves of Calophyllum cordato-oblongum gave D:A-friedo-oleanan-3-one, 28-hydroxy-D:A-friedo-oleanan-3-one (canophyllol) and three new coumarins: cordatolides A and B and oblongulide.     

Evaluating the Efficacy of Entomopathogenic Fungi against the Bark Beetle,Ips stebbingi Strohmeyer (Coleoptera,Curculionidae: Scolytinae) in India

The bark beetle, Ips stebbingi Strohmeyer (Coleoptera: Curculionidae: Scolytinae) is one of the most serious pests of Pinus wallichiana A. B. Jacks (Pinaceae) in Kashmir Himalaya. In order to find an effective biocontrol agent against this pest, we determined the effectiveness of entomopathogenic fungi, viz. Beauveria bassiana (Balsamo) Vuillemin, Metarhizium anisopliae sensu lato (Metchnikoff) Sorokin, and Lecanicillium lecanii (Zimmerman) Zare et Gams against I. stebbingi in the laboratory conditions. Each fungal suspension contained 1.0 × 10⁹ spores of fungi in 1 ml. The insecticide (cyclone 505 EC) was also used as positive control in the experiment. The mortality caused with these fungi was recorded in treated branches and Petri dish assay. In treated branches, B. bassiana and M. anisopliae caused higher mortality, i.e., 68% and 71.25%, respectively, 10 days after treatment, and 93.10% and 88%, respectively, 20 days after treatment. The results of Petri dish assay revealed that I. stebbingi adults were highly susceptible to both treated fungal species and insecticide. However, B. bassiana and M. anisopliae caused higher percentage mortality six days after treatment, i.e., 94.16% and 100% respectively. The percentage of mortality caused by treating with insecticide was 60%. Lecanicillium lecanii was found significantly less virulent (mortality 18.33%) in all fungal treatments. Results obtained in the present study are promising and may be used as alternative means of chemical control for management of this beetle pest; however, no recommendations concerning the potential use of these fungal pathogens for forest protection can be given, and further studies are needed in this respect, especially under field conditions.

     

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