The Cratylia mollis Seed Lectin Induces Membrane Permeability Transition in Isolated Rat Liver Mitochondria and a Cyclosporine A‐Insensitive Permeability Transition in Trypanosoma cruzi Mitochondria

Previous results provided evidence that Cratylia mollis seed lectin (Cramoll 1,4) promotes Trypanosoma cruzi epimastigotes death by necrosis via a mechanism involving plasma membrane permeabilization to Ca²⁺ and mitochondrial dysfunction due to matrix Ca²⁺ overload. In order to investigate the mechanism of Ca²⁺‐induced mitochondrial impairment, experiments were performed analyzing the effects of this lectin on T. cruzi mitochondrial fraction and in isolated rat liver mitochondria (RLM), as a control. Confocal microscopy of T. cruzi whole cell revealed that Cramoll 1,4 binding to the plasma membrane glycoconjugates is followed by its internalization and binding to the mitochondrion. Electrical membrane potential (?Ψ_m) of T. cruzi mitochondrial fraction suspended in a reaction medium containing 10 μM Ca²⁺ was significantly decreased by 50 μg/ml Cramoll 1,4 via a mechanism insensitive to cyclosporine A (CsA, membrane permeability transition (MPT) inhibitor), but sensitive to catalase or 125 mM glucose. In RLM suspended in a medium containing 10 μM Ca²⁺ this lectin, at 50 μg/ml, induced increase in the rate of hydrogen peroxide release, mitochondrial swelling, and ?Ψ_m disruption. All these mitochondrial alterations were sensitive to CsA, catalase, and EGTA. These results indicate that Cramoll 1, 4 leads to inner mitochondrial membrane permeabilization through Ca²⁺ dependent mechanisms in both mitochondria. The sensitivity to CsA in RLM characterizes this lectin as a MPT inducer and the lack of CsA effect identifies a CsA‐insensitive MPT in T. cruzi mitochondria.     

Allometric relationship between body mass and aerobic metabolism in zebrafish Danio rerio

The relationship between body mass (M) and metabolic rate was investigated through the assessment of active (R_A) and standard (R_S) metabolic rate at different life stages in zebrafish Danio rerio (5 day‐old larvae, 2 month‐old juveniles and 6 month‐old adults). Scaling exponents and constants were assessed for standard (R_S = 0·273M^0·965 in mgO₂ g^?1 h^?1) and active metabolic rate (R_A = 0·799M^0·926 in mgO₂ g^?1 h^?1). These data provide the basis for further experiments regarding the effects of environmental factors on aerobic metabolism throughout the life cycle of this species.     

Synthesis,characterization, and biological activity of poly(arginine)‐derived cancer‐targeting peptides in HepG2 liver cancer cells

The solid‐phase synthesis, structural characterization, and biological evaluation of a small library of cancer‐targeting peptides have been determined in HepG2 hepatoblastoma cells. These peptides are based on the highly specific Pep42 motif, which has been shown to target the glucose‐regulated protein 78 receptors overexpressed and exclusively localized on the cell surface of tumors. In this study, Pep42 was designed to contain varying lengths (3–12) of poly(arginine) sequences to assess their influence on peptide structure and biology. Peptides were effectively synthesized by 9‐fluorenylmethoxycarbonyl‐based solid‐phase peptide synthesis, in which the use of a poly(ethylene glycol) resin provided good yields (14–46%) and crude purities >95% as analyzed by liquid chromatography–mass spectrometry. Peptide structure and biophysical properties were investigated using circular dichroism spectroscopy. Interestingly, peptides displayed secondary structures that were contingent on solvent and length of the poly(arginine) sequences. Peptides exhibited helical and turn conformations, while retaining significant thermal stability. Structure–activity relationship studies conducted by flow cytometry and confocal microscopy revealed that the poly(arginine) derived Pep42 sequences maintained glucose‐regulated protein 78 binding on HepG2 cells while exhibiting cell translocation activity that was contingent on the length of the poly(arginine) strand. In single dose (0.15 mM) and dose‐response (0–1.5 mM) cell viability assays, peptides were found to be nontoxic in human HepG2 liver cancer cells, illustrating their potential as safe cancer‐targeting delivery agents. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.     

The tomato mutation nxd1 reveals a gene necessary for neoxanthin biosynthesis and demonstrates that violaxanthin is a sufficient precursor for abscisic acid biosynthesis

Carotenoid pigments are indispensable for plant life. They are synthesized within plastids where they provide essential functions in photosynthesis. Carotenoids serve as precursors for the synthesis of the strigolactone phytohormones, which are made from β‐carotene, and of abscisic acid (ABA), which is produced from certain xanthophylls. Despite the significant progress that has been made in our understanding of the carotenoid biosynthesis pathway, the synthesis of the xanthophyll neoxanthin has remained unknown. We report here on the isolation of a tomato (Solanum lycopersicum) mutant, neoxanthin‐deficient 1 (nxd1), which lacks neoxanthin, and on the cloning of a gene that is necessary for neoxanthin synthesis in both tomato and Arabidopsis. The locus nxd1 encodes a gene of unknown function that is conserved in all higher plants. The activity of NXD1 is essential but cannot solely support neoxanthin synthesis. Lack of neoxanthin does not significantly reduce the fitness of tomato plants in cultivated field conditions and does not impair the synthesis of ABA, suggesting that in tomato violaxanthin is a sufficient precursor for ABA production in vivo.     

Length–weight relationships of 16 fish species from the Liuxihe national aquatic germplasm resources conservation area,Guangdong, China

Length–weight relationships were estimated for 16 fish species (Cyprinidae) from the Liuxihe National Aquatic germplasm resources conservation areas in China. This study presents the first reference on length–weight relationships for 12 species and new records of maximum length for six species.     

Meta-analysis of ART outcomes in women with different preconception TSH levels

Background

To assess whether elevated thyroid-stimulating hormone (TSH) levels before conception can predict poor outcomes of assisted reproductive technology (ART).

Methods

Prior to July 2018, we searched the PubMed, EMBASE, COCHRANE, Google Scholar, and CNKI databases for studies. Retrospective or prospective reports that compared ART results in patients with subclinical hypothyroidism (SCH) with normal thyroid function were selected. Two reviewers separately reviewed each potential article for qualification, analyzed the quality of the studies according to the Newcastle-Ottawa scale, and extracted the data. The PRISMA guidelines were adopted.

Results

We selected a total of 18 publications that included 14,846 participants for this meta-analysis. When the TSH cut-off value for SCH was set at 2.5 mIU/L, no significant differences were observed in ART-related outcomes between SCH patients and normal women. The evaluated outcomes included the live birth rate (LBR) (OR: 0.93; 95% CI (0.77,1.12), P =?0.43), clinical pregnancy rate (CPR) (OR:1.02; 95% CI (0.90,1.17); P =?0.74), pregnancy rate (PR) (OR: 1.00; 95% CI (0.89,1.12); P =?0.99), and miscarriage rate (MR) (OR:1.24; 95% CI (0.85, 1.80); P =?0.26). Furthermore, when a higher TSH level was used as the cut-off value to diagnose SCH (i.e., 3.5–5 mIU/L), a significant difference was found in the MR (OR: 1.91; 95% CI (1.09, 3.35); P =?0.02) between the two groups of ART-treated women. However, when a broader cut-off value was used to define SCH, no significant differences were observed in the LBR (OR: 0.72; 95% CI (0.47,1.11); P =?0.14), CPR (OR: 0.82; 95% CI (0.66,1.00); P =?0.052), or PR (OR: 1.07; 95% CI (0.72,1.60); P =?0.74) between the two groups of ART-treated women.

Conclusion

No difference was observed in ART outcomes when a TSH cut-off value of 2.5 mIU/L was used. However, when a broader TSH cut-off value was used, preconception SCH resulted in a higher miscarriage rate than in normal women.

     

Male age and strain affect ejaculate quality in the Mexican fruit fly

Aging in all organisms is inevitable. Male age can have profound effects on mating success and female reproduction, yet relatively little is known on the effects of male age on different components of the ejaculate. Furthermore, in mass‐reared insects used for the Sterile Insect Technique, there are often behavioral differences between mass‐reared and wild males, while differences in the ejaculate have been less studied. The ejaculate in insects is composed mainly of sperm and accessory gland proteins. Here, we studied how male age and strain affected (i) protein quantity of testes and accessory glands, (ii) the biological activity of accessory gland products injected into females, (iii) sperm viability, and (iv) sperm quantity stored by females in wild and mass‐reared Anastrepha ludens (Diptera: Tephritidae). We found lower protein content in testes of old wild males and lower sperm viability in females mated with old wild males. Females stored more sperm when mated to young wild males than with young mass‐reared males. Accessory gland injections of old or young males did not inhibit female remating. Knowledge of how male age affects different ejaculate components will aid our understanding on investment of the ejaculate and possible postcopulatory consequences on female behavior.     

Photosynthetic temperature responses of four neem (Azadirachta indica A. Juss) provenances in the dry-hot valley area of China

The temperature dependences of net photosynthetic rate (P _N), stomatal conductance (g _s), transpiration rate (E) and dark respiration (R _D) of four neem (Azadirachta indica A. Juss) provenances of 11 years old were measured in three seasons of 2006 in the dry-hot valley area of southwest China under field conditions. The results indicated that P _N of four neem provenances showed clear parabolic responses with the increase of temperature. The optimum temperature of P _N was around 25°C in initiation stage and 30°C in prosperous stage except for neem originating from Jodhpur (MA) provenance which was very close to the mean daily temperature of the preceding week while it was around 27°C (MA provenance excepted) in last stage which was rather close to the mean daily maximum temperature of the preceding week. The optimum temperature for P _N of MA provenance was about 2–4°C higher than that of the other three neem provenances in prosperous stage and last stage. According to the fitted parameters of photosynthetic temperature response curves, the photosynthetic performance in prosperous stage was more sensitive to temperature changes than that in initiation stage and last stage while the photosynthetic performance of neem originating from MA provenance was less sensitive to temperatures than that of neem originating from Kalyani, New Delhi and Kulapachta provenances in each growing stage. Furthermore, the temperature ranges for P _N of MA provenance were much wider than those of the remaining provenances in each growing stage. These differences in photosynthetic temperature acclimation between neem provenances not only reflected temperature regime of native habitats of these provenances but suggested that MA provenance could be more tolerant to extreme temperatures compared with the remaining provenances. The temperature response curves of g _s and E were generally similar in form in the same growing stage for all neem provenances; however, shape of the response curves in initiation stage and last stage was similar to parabolic curve while that in prosperous stage was similar to linear relation. The temperature for maximum g _s and E in initiation stage was close to the optimum temperature of P _N, but the maximum g _s reached at much lower temperature than P _N and E in last stage. The response of R _D to temperature increased exponentially with temperature; however, there were obvious differences in different growing stages. R _D in initiation stage was markedly higher than that in prosperous stage and last stage at a given temperature for four neem provenances. These results suggested that four neem provenances can acclimate to their growing environment through changed photosynthetic ecophysiological responses in course of subjecting to seasonal variation of temperature.