Acute Doxorubicin insult in the mouse ovary is cell- and follicle-type dependent

Primary ovarian insufficiency (POI) is one of the many unintended consequences of chemotherapy faced by the growing number of female cancer survivors. While ovarian repercussions of chemotherapy have long been recognized, the acute insult phase and primary sites of damage are not well-studied, hampering efforts to design effective intervention therapies to protect the ovary. Utilizing doxorubicin (DXR) as a model chemotherapy agent, we defined the acute timeline for drug accumulation, induced DNA damage, and subsequent cellular and follicular demise in the mouse ovary. DXR accumulated first in the core ovarian stroma cells, then redistributed outwards into the cortex and follicles in a time-dependent manner, without further increase in total ovarian drug levels after four hours post-injection. Consistent with early drug accumulation and intimate interactions with the blood supply, stroma cell-enriched populations exhibited an earlier DNA damage response (measurable at 2 hours) than granulosa cells (measurable at 4 hours), as quantified by the comet assay. Granulosa cell-enriched populations were more sensitive however, responding with greater levels of DNA damage. The oocyte DNA damage response was delayed, and not measurable above background until 10-12 hours post-DXR injection. By 8 hours post-DXR injection and prior to the oocyte DNA damage response, the number of primary, secondary, and antral follicles exhibiting TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling)-positive granulosa cells plateaued, indicating late-stage apoptosis and suggesting damage to the oocytes is subsequent to somatic cell failure. Primordial follicles accumulate significant DXR by 4 hours post-injection, but do not exhibit TUNEL-positive granulosa cells until 48 hours post-injection, indicating delayed demise. Taken together, the data suggest effective intervention therapies designed to protect the ovary from chemotherapy accumulation and induced insult in the ovary must act almost immediately to prevent acute insult as significant damage was seen in stroma cells within the first two hours.     

The Catecholaminergic Polymorphic Ventricular Tachycardia Mutation R33Q Disrupts the N-terminal Structural Motif That Regulates Reversible Calsequestrin Polymerization

Calsequestrin undergoes dynamic polymerization with increasing calcium concentration by front-to-front dimerization and back-to-back packing, forming wire-shaped structures. A recent finding that point mutation R33Q leads to lethal catecholaminergic polymorphic ventricular tachycardia (CPVT) implies a crucial role for the N terminus. In this study, we demonstrate that this mutation resides in a highly conserved alternately charged residue cluster (DGKDR; cluster 1) in the N-terminal end of calsequestrin. We further show that this cluster configures itself as a ring system and that the dipolar arrangement within the cluster brings about a critical conformational flip of Lys³¹-Asp³² essential for dimer stabilization by formation of a H-bond network. We additionally show that Ca²⁺-induced calsequestrin aggregation is nonlinear and reversible and can regain the native conformation by Ca²⁺ chelation with EGTA. This study suggests that cluster 1 works as a molecular switch and governs the bidirectional transition between the CASQ2 monomer and dimer. We further demonstrate that mutations disrupting the alternating charge pattern of the cluster, including R33Q, impair Ca²⁺-CASQ2 interaction, leading to altered polymerization-depolymerization dynamics. This study provides new mechanistic insight into the functional effects of the R33Q mutation and its potential role in CPVT.     

Biotechnological applications of microbial bioconversions

Modern research has focused on the microbial transformation of a huge variety of organic compounds to obtain compounds of therapeutic and/or industrial interest. Microbial transformation is a useful tool for producing new compounds, as a consequence of the variety of reactions for natural products. This article describes the production of many important compounds by biotransformation. Emphasis is placed on reporting the metabolites that may be of special interest to the pharmaceutical and biotechnological industries, as well as the practical aspects of this work in the field of microbial transformations.     

Spectral lights trigger biomass accumulation and production of antioxidant secondary metabolites in adventitious root cultures of Stevia rebaudiana (Bert.)

Stevia rebaudiana (S. rebaudiana) is the most important therapeutic plant species and has been accepted as such worldwide. It has a tendency to accumulate steviol glycosides, which are 300 times sweeter than marketable sugar. Recently, diabetic patients commonly use this plant as a sugar substitute for sweet taste. In the present study, the effects of different spectral lights were investigated on biomass accumulation and production of secondary metabolites in adventitious root cultures of S. rebaudiana. For callus development, leaf explants were excised from seed-derived plantlets and inoculated on a Murashige and Skoog (MS) medium containing the combination of 2,4-dichlorophenoxy acetic acid (2, 4-D, 2.0 mg/l) and 6-benzyladenine (BA, 2.0 mg/l), while 0.5 mg/l naphthalene acetic acid (NAA) was used for adventitious root culture. Adventitious root cultures were exposed to different spectral lights (blue, green, violet, red and yellow) for a 30-day period. White light was used as control. The growth kinetics was studied for 30 days with 3-day intervals. In this study, the violet light showed the maximum accumulation of fresh biomass (2.495 g/flask) as compared to control (1.63 g/flask), while red light showed growth inhibition (1.025 g/flask) as compared to control. The blue light enhanced the highest accumulation of phenolic content (TPC; 6.56 mg GAE/g DW), total phenolic production (TPP; 101 mg/flask) as compared to control (5.44 mg GAE/g DW; 82.2 mg GAE/g DW), and exhibited a strong correlation with dry biomass. Blue light also improved the accumulation of total flavonoid content (TFC; 4.33 mg RE/g DW) and total flavonoid production (TFP; 65 mg/flask) as compared to control. The violet light showed the highest DPPH inhibition (79.72%), while the lowest antioxidant activity was observed for control roots (73.81%). Hence, we concluded that the application of spectral lights is an auspicious strategy for the enhancement of the required antioxidant secondary metabolites in adventitious root cultures of S. rebaudiana and of other medicinal plants.     

The use of otolith shape to determine stock structure of <Emphasis Type="Italic">Engraulis encrasicolus</Emphasis> along the Tunisian coast

Engraulis encrasicolus is of great economic importance in the Mediterranean. However, little is known about its stock structure. Otolith shape analysis has been successfully used for fish stock identification. In this study, the stock structure of anchovy caught off the open sea and the coastal area of the Gulf of Tunis, lagoon of Bizerte and Lake of Ichkeul were investigated using otolith shape. Otolith shape was determined by Fourier analysis and then compared among specimens sampled from different areas with forward stepwise canonical discriminant analysis. Significant differences in otolith shape between the open sea and inshore anchovy groups were detected. Otolith shape of anchovy collected in the Lake of Ichkeul was distinct from the other groups. This finding suggests a clear discreteness of the open sea and the continental groups. The data highlighted the potential for using otolith shape analysis for anchovy stock identification, as well as the role of oceanographic features in determining stock separation. These findings will have major implications for anchovy fisheries management in Tunisia. By using a precautionary approach and considering the three areas as separate stocks, fisheries management strategies should be adjusted to achieve optimum sustainable production from each stock and to avoid decreases in genetic variety.     

Involvement of testicular DAAM1 expression in zinc protection against cadmium‐induced male rat reproductive toxicity

In order to verify the effects of exposure to Cd and Zn on testicular DAAM1 gene and protein expression and also to ascertain their involvement in the protective role of Zn in prevent the testicular toxicity Cd‐induced in male offspring rats at adult age after gestational and lactational exposure, male offspring rats, from mothers receiving either tap water, Cd, Zn, or Cd + Zn during gestation and lactation periods, were scarified on postnatal days (PND) 70. The reproductive organ (testis, epididymis, and vesicle seminal) were collected, weighed, and analyzed. The results showed that exposure to Cd in utero and through lactation decreased the relative reproductive organ weight, altered the testicular histology at the interstitial and tubular levels, and causing a significant reduction in the daily sperm production (DSP) per testis and per gram of testis, and other then altering the epididymal sperm quality. Furthermore, both mRNA and protein expression of rat testicular DAAM1 were also inhibited in Cd‐treated group. Zn supply has completely corrected the most of these toxic effects. Our results imply that Zn could prevent Cd‐induced testicular toxicity and sperm quality alteration in adult male rat after gestational and lactational exposure, probably via the restoration of the testicular DAAM1 expression inhibited by Cd.     

Water-soluble fractions from defatted sesame seeds protect human neuroblast cells against peroxyl radicals and hydrogen peroxide-induced oxidative stress

Oxidative stress is involved in the development of aging-related diseases, such as neurodegenerative diseases. Dietary antioxidants that can protect neuronal cells from oxidative damage play an important role in preventing such diseases. Previously, we reported that water-soluble fractions purified from defatted sesame seed flour exhibit good antioxidant activity in vitro. In the present study, we investigated the protective effects of white and gold sesame seed water-soluble fractions (WS-wsf and GS-wsf, respectively) against 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) and hydrogen peroxide (H₂O₂) induced oxidative stress in human neuroblast SH-SY5Y cells. Pretreatment with WS-wsf and GS-wsf did not protect cells against AAPH-induced cytotoxicity, while simultaneous co-treatment with AAPH significantly improved cell viability and inhibited membrane lipid peroxidation. These results suggest that WS-wsf and GS-wsf protect cells from AAPH-induced extracellular oxidative damage via direct scavenging of peroxyl radicals. When oxidative stress was induced by H₂O₂, pretreatment WS-wsf and GS-wsf significantly enhanced cell viability. These results suggest that in addition to radical scavenging, WS-wsf and GS-wsf enhance cellular resistance to intracellular oxidative stress by activation of the Nrf-2/ARE pathway as confirmed by the increased Nrf2 protein level in the nucleus and increased heme oxygenase 1 (HO-1) mRNA expression. The roles of ferulic and vanillic acids as bioactive antioxidants in these fractions were also confirmed. In conclusion, our results indicated that WS-wsf and GS-wsf, which showed antioxidant activity in vitro, are also efficient antioxidants in a cell system protecting SH-SY5Y cells against both extracellular and intracellular oxidative stress.