Early developmental and allometric patterns in the electric yellow cichlid Labidochromis caeruleus

The electric yellow cichlid Labidochromis caeruleus is a mouth‐brooding haplochromine cichlid from Lake Malawi and one of the most popular cichlids in the ornamental fish industry. To investigate the early development of L. caeruleus from hatching until the juvenile stage, we studied its morphological development and allometric growth patterns. In newly‐hatched larvae, most organs and body parts were not yet differentiated and continued to develop until 15 days post hatching (dph). The yolk sac was depleted at 13 dph. There was allometric growth, primarily in the anterior and posterior regions of the body, and inflection points when trajectories of allometric growth changed. Head and tail growth was prioritized, suggesting that body parts linked to feeding and swimming behaviour mature earlier than the rest of the body. Additionally, growth patterns revealed that development of organs related to vital functions such as branchial respiration, sensation, exogenous feeding and swimming was prioritized. Comparisons with other African and Neotropical cichlids revealed differences in ontogenetic processes and allometric growth along the anterior–posterior axis as well as variation in developmental timing. These results indicate how early morphological development and ontogenic processes might respond to the distinctive parental care observed in mouth‐brooding cichlids.     

Length‐weight and length–length relationships of three algae‐scraping cyprinid species from Iran

The study presents length–weight relationships (LWRs) and length–length relationships (LLRs) for three algae‐scraper species; Capoeta coadi from the Kouhrang River (Iran; 32°23′N, 50°08′E) a part of the Tigris drainage basin, Capoeta pyragyi from Cheshmeh Langan River (32°55′N, 50°10′E) a part of Zayanderud River basin and Capoeta umbla from Chooman River (35°57′N, 45°47′E). Fish were sampled by electro fishing (Samus1000; Power Out: 200 watts) in August, September and October 2017. Sampling was carried out each months in sites covering an area of about 100 m² including runs, riffles and pools at a water depth of 10–60 cm. The obtained LWRs and LLRs showed a high level of correlation (r² > 0.99).     

Schizophyllan production by newly isolated fungus <Emphasis Type="Italic">Schizophyllum commune</Emphasis> IBRC-M 30213: optimization of culture medium using response surface methodology

Schizophyllan (SPG) is a commercially attractive biopolymer produced by Schizophyllum commune. An investigation on the potential for SPG production by Iranian native S. commune was conducted based on culture medium, fermentation conditions and bioreactor type, . Nine native fungal strains were isolated from the northern forest of Iran at different times. Based on growth rate and SPG production, one strain was selected for further study. Optimal medium composition and inoculum size for maximizing SPG production and minimizing biomass were determined using central composite design by setting sucrose, yeast extract, inoculum size, carboxymethyl cellulose and oleic acid in the ranges of 50–200 g/L, 1–4 g/L, 2–10%, 2–12 g/L and 0.032–0.222%, respectively. The results showed that optimal results were obtained at 93.47 g/L sucrose, 1.87 g/L yeast extract, 7.68% inoculum size, 9.07 g/L carboxymethyl cellulose and 0.13% oleic acid, with maximum SPG production of 9.97 g/L and minimum biomass of 35.18 g/L. Under these optimal conditions, the production of SPG was studied in stirred tank and bubble column bioreactors. The results revealed greater production in the stirred tank because of better mixing of the culture medium. The SPG produced was characterized using rheometery, Fourier transform infrared spectroscopy, nuclear magnetic resonance), scanning electron microscopy and gel permeation chromatography. The results of these characterizations demonstrated the similarity of the SPG produced by S. commune IBRC-M 30213 to commercial SPG. Thus, the SPG produced shows good potential as a polysaccharide for use in various industries.     

Carbon Nanoparticles in High‐Performance Perovskite Solar Cells

In the past few years, organic–inorganic metal halide ABX₃ perovskites (A = Rb, Cs, methylammonium, formamidinium (FA); B = Pb, Sn; X = Cl, Br, I) have rapidly emerged as promising materials for photovoltaic applications. Tuning the film morphology by various deposition techniques and additives is crucial to achieve solar cells with high performance and long‐term stability. In this work, carbon nanoparticles (CNPs) containing functional groups are added to the perovskite precursor solution for fabrication of fluorine‐doped tin oxide/TiO₂/perovskite/spiro‐OMeTAD/gold devices. With the addition of CNPs, the perovskite films are thermally more stable, contain larger grains, and become more hydrophobic. NMR experiments provide strong evidence that the functional groups of the CNPs interact with FA cations already in the precursor solution. The fabricated solar cells show a power‐conversion efficiency of 18% and negligible hysteresis.     

On the benefit of melatonin in protection against ouabain-induced arrhythmia through modulation of oxidative stress factors in isolated rat atria

Considering the cardioprotective and antioxidant properties of melatonin, in the present experiment, we investigated the possible involvement of oxidative stress factors in antiarrhythmic effects of melatonin in ouabain-induced arrhythmia in isolated rat atria. Male rats were divided into two groups, receiving either of melatonin (2 mg/kg) or vehicle, orally once daily for three weeks. Rats were anesthetized, and atria were isolated and incubated with ouabain in an organ bath. Time of onset of arrhythmia and asystole as well as atrial beating rate and contractile force were recorded. We also measured the activity of superoxide dismutase (SOD) and levels of thiobarbituric acid reactive substances (TBARS) in atria after injection of ouabain to animals. Pretreatment of animals with melatonin could significantly postpone the onset of arrhythmia and asystole compared with vehicle-treated group (P ≤ 0.001). Incubation of ouabain boosted the atrial beating rate in vehicle-treated group (P ≤ 0.01), while this response in melatonin-treated group was not significant (P > 0.05). Injection of ouabain decreased the activity of SOD and increased the levels of TBARS in atria (P ≤ 0.001, P ≤ 0.01, respectively), while pretreatment of animals with melatonin reversed these effects (P ≤ 0.05). It is concluded that melatonin possesses antiarrhythmic properties, and oxidative stress factors might mediate this response.     

Saffron carotenoids (crocin and crocetin) binding to human serum albumin as investigated by different spectroscopic methods and molecular docking

Therapeutic effects of saffron ingredients were studied in some diseases. The pharmacokinetics and pharmacodynamics of these ingredients were also studied, but their transport mechanism is not clearly known. Serum albumin has been known as the most important transporter of many drugs in the body that affects their disposition, transportation, and bioavailability. Here, we investigated the interaction of crocin (Cro) with HSA, for the first time, and compared with the crocetin (Crt)–HSA interaction. UV and fluorescence spectroscopy, circular dichroism (CD), and molecular docking was applied to investigate the possibility and mechanism of binding of HSA with these natural carotenoids. The gradually addition of Cro increased HSA absorbency at 278 nm, while Crt decreased it. Both of these changes induced HSA unfolding that was confirmed by the decreased α-helix content, as determined by the CD. Both carotenoids quenched HSA fluorescence emission, but with different mechanisms. The Stern–Volmer plots indicated a dynamic quenching of intrinsic emission of HSA due to Cro addition, while Crt quenching followed both static and dynamic quenching mechanisms. Docking results indicated binding of Cro/Crt in sub-domain IIA, Sudlow site I of HSA, which accompanied with the hydrogen bonding of Cro/Crt with Tyr138. The interaction of these ligands (Cro/Crt) caused HSA unfolding and affects the hydrophobic environment of Trp241, which result in the quenching of Trp fluorescence. The UV spectroscopy and fluorescence quenching data indicated the differences in the mechanisms of interaction of Cro/Crt with HSA, which is due to the differences in the structure and hydrophobicity of these ligands.