<Emphasis Type="Italic">Plasmodium falciparum</Emphasis> apicoplast and its transcriptional regulation through calcium signaling

Malaria has been present since ancient time and remains a major global health problem in developing countries. Plasmodium falciparum belongs to the phylum Apicomplexan, largely contain disease-causing parasites and characterized by the presence of apicoplast. It is a very essential organelle of P. falciparum responsible for the synthesis of key molecules required for the growth of the parasite. Indispensable nature of apicoplast makes it a potential drug target. Calcium signaling is important in the establishment of malaria parasite inside the host. It has been involved in invasion and egress of merozoites during the asexual life cycle of the parasite. Calcium signaling also regulates apicoplast metabolism. Therefore, in this review, we will focus on the role of apicoplast in malaria biology and its metabolic regulation through Ca⁺⁺ signaling.     

Effects of seed moisture content,warm, chilling,and exogenous hormone treatments and germination temperature on the germination of blackthorn seeds

Blackthorn (Prunus spinosa L.) germination is often low, so new methods need to be developed with a view to improving nursery yields and to inform decision-making on natural regeneration. To this end, the effects of seed moisture content (MC) levels in combination with warm and chilling treatments on blackthorn seed dormancy release were investigated. In another experiment, the effect on seed germination of warm and chilling treatments in combination with exogenous hormones was investigated. Following treatment, the seeds were allowed to germinate at a constant 15°C with 8 h lighting per day or 20 (dark)/30°C (light). Seed lot effects were evident, but were consistent across treatments. Seeds adjusted to the lower target MC level (TMC) maintained high germination potential over a longer period of treatment than in those held in the fully imbibed (FI) state. The highest germination was achieved in the TMC seeds that were given six weeks warm treatment followed by 32 weeks chilling. Hormone treatments significantly reduced the amount of chilling needed to release dormancy in TMC seeds, but not in the FI seeds. Overall, germination response was better at 15°C test temperature than at 20/30°C.     

Floral constraint resulting from intersexual mimicry in a gynodioecious fig tree

Fig trees (Ficus: Moraceae) are pollinated by female fig wasps (Agaonidae) whose larvae develop inside galled flowers of unusual inflorescences (figs). Most fig trees also support communities of non‐pollinating fig wasps. Figs of different species display great size variation and contain tens to tens of thousands of flowers. Around one‐half the species of fig trees have the gynodioecious breeding system, where female trees have figs that produce seeds and male trees have figs that support development of pollinators. Mutual mimicry between receptive male and female figs ensures that pollinators enter female figs, even though the insects will die without reproducing, but the need to give no sex‐specific cues to the pollinators may constrain differences in size between receptive male and female figs. We compared relationships between inflorescence size and some measures of reproductive success in male and female figs of Ficus montana grown under controlled conditions in the presence of the pollinator Kradibia tentacularis and its main parasitoid Sycoscapter sp. indesc. Female figs that contained more flowers produced more seeds, but male figs did not increase the production of female pollinator K. tentacularis fig wasps in proportion of the flower number. Although more flowers were galled by the pollinators in male figs containing more female flowers, the high larval mortality caused by parasitism and nutritional limitation prevented the increase in the production of adult female offspring. Selection may favor the increase in flower numbers within figs in female plants of F. montana, but contrarily constrain this attribute in male plants.     

Targeting Colon Cancer Cells with Pyrazino-Imidazolinone Derivatives: Synthesis,Molecular Docking,and in Vitro Evaluation of Anti-Proliferative and Pro-Apoptotic Activities

We report the synthesis, spectroscopic characterization, molecular docking and biological evaluation of nine pyrazino-imidazolinone derivatives. These derivatives were evaluated for their anticancer activity against three cancer cell lines: 518A2 melanoma, HCT-116, and HCT-116 p53 knockout mutant colon carcinoma. The MTT assay was employed to assess their effectiveness. Among the nine compounds tested, four compounds (5 a, 5 d, 5 g, and 5 h) exhibited promising antiproliferative activity specifically against HCT-116 p53-negative cells (IC₅₀ 0.23, 0.20, 2.07 and 58.75 μM, respectively). Interestingly, treatment with the 3,4-dimethoxyphenyl derivative 5a resulted in a significant increase (199 %) in caspase activity in HCT-116 p53-negative cells compared to untreated cells while the bromo-pyrazine derivative 5d demonstrated (190 %) increase. These findings suggest that compounds 5a and 5 d induce p53-independent apoptotic cell death. Additionally, in silico molecular docking studies with EGFR and tyrosinase proteins indicated that compounds 5 d and 5 e have the potential to bind to important anticancer drug targets.     

Localization and subcellular association of Grapevine Pinot Gris Virus in grapevine leaf tissues

Despite the increasing impact of Grapevine Pinot gris disease (GPG-disease) worldwide, etiology about this disorder is still uncertain. The presence of the putative causal agent, the Grapevine Pinot Gris Virus (GPGV), has been reported in symptomatic grapevines (presenting stunting, chlorotic mottling, and leaf deformation) as well as in symptom-free plants. Moreover, information on virus localization in grapevine tissues and virus-plant interactions at the cytological level is missing at all. Ultrastructural and cytochemical investigations were undertaken to detect virus particles and the associated cytopathic effects in field-grown grapevine showing different symptom severity. Asymptomatic greenhouse-grown grapevines, which tested negative for GPGV by real time RT-PCR, were sampled as controls. Multiplex real-time RT-PCR and ELISA tests excluded the presence of viruses included in the Italian certification program both in field-grown and greenhouse-grown grapevines. Conversely, evidence was found for ubiquitous presence of Grapevine Rupestris Stem Pitting-associated Virus (GRSPaV), Hop Stunt Viroid (HSVd), and Grapevine Yellow Speckle Viroid 1 (GYSVd-1) in both plant groups. Moreover, in every field-grown grapevine, GPGV was detected by real-time RT-PCR. Ultrastructural observations and immunogold labelling assays showed filamentous flexuous viruses in the bundle sheath cells, often located inside membrane-bound organelles. No cytological differences were observed among field-grown grapevine samples showing different symptom severity. GPGV localization and associated ultrastructural modifications are reported and discussed, in the perspective of assisting management and control of the disease.     

Structural vaccinology approach to investigate the virulent and secretory proteins of Bacillus anthracis for devising anthrax next-generation vaccine

Abstract

Communicated by Ramaswamy H. Sarma     

Comparative analysis of bacterial community-metagenomics in coastal Gulf of Mexico sediment microcosms following exposure to Macondo oil (MC252)

The indigenous bacterial communities in sediment microcosms from Dauphin Island (DI), Petit Bois Island (PB) and Perdido Pass (PP) of the coastal Gulf of Mexico were compared following treatment with Macondo oil (MC252) using pyrosequencing and culture-based approaches. After quality-based trimming, 28,991 partial 16S rRNA sequence reads were analyzed by rarefaction, confirming that analyses of bacterial communities were saturated with respect to species diversity. Changes in the relative abundances of Proteobacteria, Bacteroidetes and Firmicutes played an important role in structuring bacterial communities in oil-treated sediments. Proteobacteria were dominant in oil-treated samples, whereas Firmicutes and Bacteroidetes were either the second or the third most abundant taxa. Tenericutes, members of which are known for oil biodegradation, were detected shortly after treatment, and continued to increase in DI and PP sediments. Multivariate statistical analyses (ADONIS) revealed significant dissimilarity of bacterial communities between oil-treated and untreated samples and among locations. In addition, a similarity percentage analysis showed the contribution of each species to the contrast between untreated and oil-treated samples. PCR amplification using DNA from pure cultures of Exiguobacterium,  Pseudoalteromonas,  Halomonas and Dyadobacter, isolated from oil-treated microcosm sediments, produced amplicons similar to polycyclic aromatic hydrocarbon-degrading genes. In the context of the 2010 Macondo blowout, the results from our study demonstrated that the indigenous bacterial communities in coastal Gulf of Mexico sediment microcosms responded to the MC252 oil with altered community structure and species composition. The rapid proliferation of hydrocarbonoclastic bacteria suggests their involvement in the degradation of the spilt oil in the Gulf of Mexico ecosystem.     

Antimycobacterial activity in vitro of pigments isolated from Antarctic bacteria

In this study, we describe the antimycobacterial activity of two pigments, violacein, a purple violet pigment from Janthinobacterium sp. Ant5-2 (J-PVP), and flexirubin, a yellow-orange pigment from Flavobacterium sp. Ant342 (F-YOP). These pigments were isolated from bacterial strains found in the land-locked freshwater lakes of Schirmacher Oasis, East Antarctica. The minimum inhibitory concentrations (MICs) of these pigments for avirulent and virulent mycobacteria were determined by the microplate Alamar Blue Assay (MABA) and Nitrate Reductase Assay (NRA). Results indicated that the MICs of J-PVP and F-YOP were 8.6 and 3.6 μg/ml for avirulent Mycobacterium smegmatis mc²155; 5 and 2.6 μg/ml for avirulent Mycobacterium tuberculosis mc²6230; and 34.4 and 10.8 μg/ml for virulent M. tuberculosis H₃₇Rv, respectively. J-PVP exhibited a ~15 times lower MIC for Mycobacterium sp. than previously reported for violacein pigment from Chromobacterium violaceum, while the antimycobacterial effect of F-YOP remains undocumented. Our results indicate these pigments isolated from Antarctic bacteria might be valuable lead compounds for new antimycobacterial drugs used for chemotherapy of tuberculosis.     

FbD directed fabrication and investigation of luliconazole based SLN gel for the amelioration of candidal vulvovaginitis: a 2 T (thermosensitive & transvaginal) approach

Candidal vulvovaginitis (CVV), is the second most leading vaginal infection (global prevalence > 75%), caused due to excessive growth of Candida spp., predominantly Candida albicans (>95% cases). The current treatment regimens for CVV are marred with the challenges of fungal resistance & infection recurrence, subsequently leading to the compromised therapeutic efficacy of anti-fungal drugs, prolonged treatment and low patient compliance. The core of the present research was the fabrication & investigation of 2 T-SLN (solid lipid nanoparticles) gel carrying luliconazole for the amelioration of CVV. ‘2T’ symbolizes transvaginal & thermosensitive attributes of the present formulation. SLNs were prepared by a modified melt emulsification-ultra sonication method using a combination of solid lipids (Gelucire 50/13 & Precirol ATO 5), surfactant (Tween 80) and co-surfactant (Kolliphor). Formulation by design (FbD) approach was adopted to obtain appropriately screened and tailored SLNs. The optimized SLNs yielded a particle size, polydispersity index & entrapment efficiency of 62.18 nm, 0.263 & 81.5% respectively. To formulate the 2 T-gel, the final SLNs were loaded into Carbopol 971P-NF and Triethanolamine based gel. The 2 T-SLN gel was found to be easily spreadable and homogenous with mean extrudability (15 ± 0.4 g/cm²), viscosity (696.42 ± 2.34 Pa·s) and %drug content (93.24 ± 0.73%) values.. The pH of the prepared 2 T-SLN gel (4.5 ± 0.5) was in concordance with the vaginal pH (normal conditions). For in-vitro characterization of an optimized 2 T-SLN gel the release kinetics & anticandidal activity were assessed which offers a %cumulative drug release of 62 ± 0.5% in 72 h and 37.3 ± 1.5 mm zone of inhibition in 48 h. The visual appearance & dimensions were determined using fluorescent microscopy (spherical shape) & transmission electron microscopy (90–120 nm) respectively. The optimized 2 T-SLN gel showcases a skin-friendly profile with no significant signs of erythema and oedema and was found to be stable at room temperature for 2 months without any visual non-uniformity/cracking/breaking. In conclusion, the current research serves a new therapeutic perspective in assessing the activity of luliconazole for vaginal drug delivery using a 2 T-SLN gel system.     

Assessment of genetic variability among selected species of Apocynaceae

Family Apocynaceae is an economically important family grown as ornamental plants and many wild species have medicinal uses as well. The aim of the present study was to understand the level and pattern of genetic variability among the selected individuals of Apocynaceae. For this purpose, three species of different genera of Apocynaceae, Thevetia peruviana, Alstonia scholaris and Catharanthus roseus, were collected from Rawalpindi and Quaid-i-Azam University forest, Islamabad. To evaluate the level of polymorphism within the species and members of different species, randomly amplified polymorphic DNA (RAPD) markers were used. A series of OPC RAPD primers were used; only six primers of OPC series gave amplification. Highest genetic variation at interspecific and intraspecific levels was shown by OPC 9 and the lowest polymorphism was observed in OPC 4. The data was analyzed by using software Statistica 5.5. In total 105 monomorphic and 272 polymorphic bands were produced from all primers. Therefore, out of 322 amplified products, 26% were monomorphic and 68% were polymorphic. Low genetic diversification was observed both at intraspecific and interspecific level. At the molecular level Alstonia scholaris and Catharanthus roseus (subfamily Plumerioideae) appeared in a group and Thevetia peruviana (subfamily Rauvolfoideae) formed another group, confirming the classification based on morphological characters.