Ripening of fleshy fruit: Molecular insight and the role of ethylene

Development and ripening in fruit is a unique phase in the life cycle of higher plants which encompasses several stages progressively such as fruit development, its maturation, ripening and finally senescence. During ripening phase, several physiological and biochemical changes take place through differential expression of various genes that are developmentally regulated. Expression and/or suppression of these genes contribute to various changes in the fruit that make it visually attractive and edible. However, in fleshy fruit massive losses accrue during post harvest handling of the fruit which may run into billions of dollars worldwide. This encouraged scientists to look for various ways to save these losses. Genetic engineering appears to be the most promising and cost effective means to prevent these losses. Most fleshy fruit ripen in the presence of ethylene and once ripening has been initiated proceeds uncontrollably. Ethylene evokes several responses during ripening through a signaling cascade and thousands of genes participate which not only sets in ripening but also responsible for its spoilage. Slowing down post ripening process in fleshy fruit has been the major focus of ripening-related research. In this review article, various developments that have taken place in the last decade with respect to identifying and altering the function of ripening-related genes have been described. Role of ethylene and ethylene-responsive genes in ripening of fleshy fruit is also included. Taking clues from the studies in tomato as a model fruit, few case studies are reviewed.     

Antennal regulation of migratory flight in the neotropical moth Urania fulgens

Migrating insects use their sensory systems to acquire local and global cues about their surroundings. Previous research on tethered insects suggests that, in addition to vision and cephalic bristles, insects use antennal mechanosensory feedback to maintain their airspeeds. Owing to the large displacements of migratory insects and difficulties inherent in tracking single individuals, the roles of these sensory inputs have never been tested in freely migrating insects. We tracked individual uraniid moths (Urania fulgens) as they migrated diurnally over the Panama Canal, and measured airspeeds and orientation for individuals with either intact or amputated flagella. Consistent with prior observations that antennal input is necessary for flight control, 59 per cent of the experimental moths could not fly after flagella amputation. The remaining fraction (41%) was flight-capable and maintained its prior airspeeds despite severe reduction in antennal input. Thus, maintenance of airspeeds may not involve antennal input alone, and is probably mediated by other modalities. Moths with amputated flagella could not recover their proper migratory orientations, suggesting that antennal integrity is necessary for long-distance navigation.     

Evaluation of neuroprotective and anti-fatigue effects of sildenafil

Sildenafil, a phosphodiesterase-5 inhibitor is widely used for the treatment of erectile dysfunction. Recently, the FDA approved the use of sildenafil in the therapeutic treatment of pulmonary arterial hypertension. Sildenafil crosses the blood-brain barrier and has been shown to enhance memory. Tremor, rigidity and akinesia are the most common symptoms seen in Parkinson's disease. Fatigue and sexual dysfunction are the other prominent features seen in Parkinson's disease. Interestingly, sildenafil is used therapeutically to treat sexual dysfunction in Parkinson's disease patients. Currently research on Parkinson's disease focuses on developing novel drug therapies for retarding the nigral dopaminergic neurodegeneration. Hence, we investigated the anti-fatigue and neuroprotective effects of sildenafil. In this study, the effect of sildenafil on fatigue was evaluated using forced swim test in mice. Sildenafil had no effect on fatigue as seen by the swim time. With regard to neuroprotective effects, we investigated the effects of sildenafil using two animal models of Parkinson's disease. In this study, 6-hydroxydopamine-lesioned (unilateral) rats and MPTP-treated mice were used as the animal models of Parkinson's disease. 6-Hydroxydopamine-lesioned rats were used to determine the effect of sildenafil on rotational behavior. Ipsilateral or contralateral rotational behavior can indicate the amphetamine-like activity or apomorphine-like activity of sildenafil. Sildenafil did not induce contralateral or ipsilateral rotations in 6-hydroxydopamine-lesioned rats. Sildenafil did not protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopamine depletion in the striatum.     

Antifungal susceptibility profiles of <Emphasis Type="Italic">Coccidioides immitis</Emphasis> and <Emphasis Type="Italic">Coccidioides posadasii</Emphasis> from endemic and non-endemic areas

Coccidioidomycosis is a systemic fungal infection endemic in Southwestern United States, Mexico, Central and South America. The causal agents are Coccidioides immitis and C. posadasii. A large number of cases of coccidioidomycosis in New York State residents were identified. We compared susceptibility profiles of these isolates and of C. immitis isolates from California using mycelial phase inoculum and CLSI (NCCLS) M38–A broth microdilution protocol. Minimum fungicidal concentrations (MFC) were also determined. Results indicated that geometric mean MICs of amphotericin B (AMB, 0.06 μg/ml), fluconazole (FLC, 8.0 μg/ml), itraconazole (ITC, 0.07 μg/ml), ketoconazole (KTC, 0.04 μg/ml), voriconazole (VRC, 0.04 μg/ml), posaconazole (PSC, 0.17 μg/ml) and caspofungin (CSP, 0.15 μg/ml) were in susceptible range as per breakpoints published for pathogenic Candida species. However, geometric MFC for FLC was relatively higher (52.4 μg/ml). Also, no significant difference in MIC and MFC values was evident for C. immitis and C. posadasii isolates. In conclusion, current methods for antifungal susceptibility testing yield reproducible profiles for Coccidioides species, which appear to be highly susceptible to most antifungal agents.     

An empirical approach for deriving specific inland water quality parameters from high spatio-spectral resolution image

Inland lake of Vembanad has benefited from continuous monitoring to evaluate water quality which has declined due to increased anthropogenic activities and climate change. Remote sensing techniques can be used to estimate and monitor inland water quality both spatially and temporally. An empirical model is presented in Vemaband lake that retrieves the specific water quality parameters through correlations between various spectral wavelengths of Sentinel-2MSI (S2MSI) with field-measured water quality parameters. This approach includes the combinations of various bands, band ratios, and band arithmetic computation of satellite sensors of spectral datasets. The specific inland water quality parameters such as chlorophyll-a (chl-a), total suspended solids (TSS), turbidity, and secchi disc depth (SDD) were retrieved from the developed water quality model through Sentinel-2A remote sensing reflectance. The result illustrates that Specific Inland Water Quality Parameters (SIWQP) strongly correlated with S2MSI reflection spectral wavelengths. The SIWQP models are constructed for TSS (R²?=?0.8008), Chl-a (R²?=?0.8055), Turbidity (R²?=?0.6329) and SDD (R²?=?0.7174).The spatial distribution of SIWQPs in Vembanad lake for March 2018 is mapped and shows the lake's water quality distribution. The research from Sentinel-2, MSI has potential and is appropriate in high spectral and spatial characteristics for retrieving and continuous monitoring of water quality parameters in the regional scale of inland water bodies.

     

Multiplex gene removal by two-step polymerase chain reactions

Precise DNA manipulation is critical for molecular biotechnology. Restriction enzyme-based approaches are limited by their requirement of specific enzyme sites. Restriction-free cloning has greatly improved the flexibility and speed of precise DNA assembly. Most of these approaches focus on DNA assembly rather than gene removal. Here we present a polymerase chain reaction (PCR)-based cloning method that allows removal of multiple gene segments from plasmids without using restriction enzymes and thermostable ligase. We demonstrate simultaneous removal of three gene segments from a plasmid. This approach could be beneficial to DNA library construction, genetic and protein engineering, and synthetic biology.     

Design and synthesis of 3-(azol-1-yl)phenylpropanes as microbicidal spermicides for prophylactic contraception

We designed a series of 25 3-(azol-1-yl)phenylpropanes which yielded 10 compounds (3, 4, 7, 8, 13, 14, 19, 21, 23, 26) that irreversibly immobilized 100% human sperm at 1% (w/v) concentration in 60 s; 12 compounds (8, 9, 15, 16, 19-21, 23-25, 27, 28) that showed potent microbicidal activity at 12.5-50 μg/mL against Trichomonas vaginalis; and 17 compounds (3-11, 13, 15, 19, 21, 23, 26, 28, 30) that exhibited potent anticandida activity with minimum inhibitory concentration (MIC) of 12.5-50 μg/mL. Almost all the compounds exhibited high level of safety towards normal vaginal flora (Lactobacillus) and human cervical (HeLa) cells in comparison to the marketed spermicide nonoxynol-9 (N-9). All the biological activities were evaluated in vitro. Two compounds (4, 8) with good safety profile exhibited multiple (spermicidal, antitrichomonas and anticandida) activities, warranting further lead optimization for furnishing a prophylactic vaginal contraceptive.     

Benzothiophene carboxamide derivatives as inhibitors of Plasmodium falciparum enoyl-ACP reductase

Benzothiophene derivatives like benzothiophene sulphonamides, biphenyls, or carboxyls have been synthesized and have found wide pharmacological usage. Here we report, bromo-benzothiophene carboxamide derivatives as potent, slow tight binding inhibitors of Plasmodium enoyl-acyl carrier protein (ACP) reductase (PfENR). 3-Bromo-N-(4-fluorobenzyl)-benzo[b]thiophene-2-carboxamide (compound 6) is the most potent inhibitor with an IC50 of 115 nM for purified PfENR. The inhibition constant (Ki) of compound 6 was 18 nM with respect to the cofactor and 91 nM with respect to crotonoyl-CoA. These inhibitors showed competitive kinetics with cofactor and uncompetitive kinetics with the substrate. Thus, these compounds hold promise for the development of potent antimalarials.