Enhancement of seminiferous tubular growth and spermatogenesis in testes of rats recovering from early hypothyroidism: a quantitative study

Testicular weight and DNA content were markedly reduced (63 and 69%) in weanling Long-Evans rat pups rendered hypothyroid from birth by administration of propylthiouracil (PTU), a reversible goitrogen. These growth deficits worsened to >80% by continuing hypothyroidism beyond weaning, to days 50 and 90. Recovery of thyroid function, brought about by discontinuing PTU at weaning, resulted in a paradoxical stimulation of testis growth, amounting to increased weight (40%), DNA content (60%) and size by 90 days, compared to age-matched controls. In the 25-day or older hypothyroid rats, testicular structure was immature and spermatogenesis markedly delayed, as evident by closed lumen and significantly reduced diameter of seminiferous tubules (38%), thickness of germinal layer (70%), and number of primary spermatocytes (86%), compared to control. Hypothyroidism did not alter the number of tubules per testis cross section. In the 90-day recovery rats, numbers of seminiferous tubules were unchanged but tubular diameter was significantly (20%) larger than in controls and spermatogenesis appeared very active as indicated by significantly increased germinal layer thickness (22%) and total number and density of primary spermatocytes (55% and 40%). The results show that although postnatal hypothyroidism is deleterious for testicular growth and spermatogenesis, recovery from this condition leads to enhanced seminiferous tubular growth and spermatogenesis.     

Salusin-α attenuates inflammatory responses in vascular endothelial cells

Atherosclerosis accounts for numerous cardiovascular diseases, and cytokines have a critical role in acceleration or suppression of disease. Salusin-α presents a new class of bioactive peptides that can have anti-atherogenic properties. Therefore, the effects of salusin-α on the expression of some pro- and anti-inflammatory cytokines and on TNF-α-induced inflammatory responses in human umbilical vein endothelial cells (HUVECs) were examined. The involvement of the NF-κB pathway in effects of salusin-α in HUVECs was checked using Bay 11-7082 as an NF-κB inhibitor. The mRNA expression of pro-inflammatory cytokines including IL-6, IL-8, and IL-18 and anti-inflammatory cytokine IL-1Ra was assessed by real-time PCR. The protein levels of cytokines were measured by the ELISA method. Salusin-α suppressed both mRNA and protein expression of pro-inflammatory cytokines and induced mRNA and protein expression of IL-1Ra in HUVECs. Salusin-α suppressed TNF-α-induced inflammatory responses in HUVECs. The down-regulatory or up-regulatory effects of salusin-α on expression of cytokines could not be influenced by Bay 11-7082 pretreatment. Our findings indicate anti-inflammatory effects of salusin-α and suggest a novel peptide-based therapeutic strategy for atherosclerosis.     

Interaction of insulin with a triblock copolymer of PEG-(fumaric-sebacic acids)-PEG: thermodynamic and spectroscopic studies

A comparative study on the interaction of (PEG-co-P(FA/SC)-co-PEG) triblock copolymer with bovine and human insulins was carried out using isothermal titration calorimetry (ITC), circular dichroism (CD), and fluorescence spectroscopy. ITC data show that the copolymer has a low affinity for both proteins, with an association constant of about 7-9 x 10(3) M (-1). Results also show that binding is enthalpically driven, and disfavored by conformational entropy. CD spectroscopy studies reveal a small increase in the helical content and a decrease in beta-structure as well as random coil in both proteins. Acrylamide quenching experiments display reduced accessibility of tyrosines, while intrinsic fluorescence spectra show lower tyrosine emission. Furthermore, thermal unfolding experiments, studied by far-UV CD at 222 and 217 nm, demonstrate that upon interaction with the copolymer helix structure becomes less stable while the stability of beta-structure remains unchanged. Altogether, these observations indicate that (PEG-co-P(FA/SC)-co-PEG) triblock copolymer has similar effect(s) on both proteins.     

Kinetics of Cr(VI) Removal by Iron Filings in Some Soils

In this research, kinetics of Cr(VI) reduction by iron filings was investigated through a batch study in seven different soils. Chromate reduction experiments were carried out for initial Cr(VI) concentrations ranging from 20 to 100 mgkg^?1 and iron filings dosage of 0 to 5% w/w. The experimental data were analyzed using various kinetic models including zero-order, pseudo first-order, power function, Elovich, and diffusion parabolic. Results showed that the Cr(VI) reduction efficiency in the presence of all studied soils increased with increasing iron filings dosage and decreased with increasing the initial Cr(VI) concentration. The reaction rates considerably depended on pH and were higher in acidic soils. The diffusion parabolic model was the best kinetic model as evidenced by the highest determination coefficient (r²) and the lowest standard error of the estimate (SE). The rate-limiting step(s) may be transport of chromate anions across a liquid film at the interface of soil-liquid, transport in liquid-filled macropores of iron filings aggregates, or diffusion in micropores and along the particle's surface.     

Liquid–liquid phase separation of Tau by self and complex coacervation

The liquid–liquid phase separation (LLPS) of Tau has been postulated to play a role in modulating the aggregation property of Tau, a process known to be critically associated with the pathology of a broad range of neurodegenerative diseases including Alzheimer''s Disease. Tau can undergo LLPS by homotypic interaction through self‐coacervation (SC) or by heterotypic association through complex‐coacervation (CC) between Tau and binding partners such as RNA. What is unclear is in what way the formation mechanisms for self and complex coacervation of Tau are similar or different, and the addition of a binding partner to Tau alters the properties of LLPS and Tau. A combination of in vitro experimental and computational study reveals that the primary driving force for both Tau CC and SC is electrostatic interactions between Tau‐RNA or Tau‐Tau macromolecules. The liquid condensates formed by the complex coacervation of Tau and RNA have distinctly higher micro‐viscosity and greater thermal stability than that formed by the SC of Tau. Our study shows that subtle changes in solution conditions, including molecular crowding and the presence of binding partners, can lead to the formation of different types of Tau condensates with distinct micro‐viscosity that can coexist as persistent and immiscible entities in solution. We speculate that the formation, rheological properties and stability of Tau droplets can be readily tuned by cellular factors, and that liquid condensation of Tau can alter the conformational equilibrium of Tau.     

The effect of inflammatory factors and their inhibitors on the hematopoietic stem cells fate

Inflammatory cytokines exert different effects on hematopoietic stem cells (HSCs), lead to the development of various cell lineages in bone marrow (BM) and are thus a differentiation axis for HSCs. The content used in this article has been obtained by searching PubMed database and Google Scholar search engine of English-language articles (1995–2020) using “Hematopoietic stem cell,” “Inflammatory cytokine,” “Homeostasis,” and “Myelopoiesis.” Inflammatory cytokines are involved in the differentiation and proliferation of hematopoietic progenitors to compensate for cellular death due to inflammation. Since each of these cytokines differentiates HSCs into a specific cell line, the difference in the effect of these cytokines on the fate of HSC progenitors can be predicted. Inhibitors of these cytokines can also control the inflammatory process as well as the cells involved in leukemic conditions. In general, inflammatory signaling can specify the dominant cell line in BM to counteract inflammation and leukemic condition via stimulating or inhibiting hematopoietic progenitors. Therefore, detection of the effects of inflammatory cytokines on the differentiation of HSCs can be an appropriate approach to check inflammatory and leukemic conditions and the suppression of these cytokines by their inhibitors allows for control of homeostasis in stressful conditions.     

The role of Pro-P5C Cycle in chs mutants of Arabidopsis under cold stress

Proline metabolism is implicated in plant responses to abiotic stresses, including the chilling stress. During proline catabolism, the two-step oxidation of proline is performed by the continuous actions of proline dehydrogenase (ProDH), which produces Δ¹-pyrroline-5-carboxylate (P5C), and P5C dehydrogenase (P5CDH), which oxidizes P5C to glutamate. The Arabidopsis thaliana chilling mutants chs1 and chs2 are sensitive to chilling temperatures of 13–18°C. For a better understanding of Arabidopsis responses to chilling stress, 4-week-old wild-type (WT) and chs1 and chs2 lines, with three plants in each group, were subjected to chilling stress (13°C), cold stress (4°C), or remained under normal conditions (23°C); and several factors including the expression of ProDH2 and P5CDH genes, POX (peroxidase) and SOD (superoxide dismutase) activities, as well as MDA and proline contents were examined. Our results showed an increase in the proline content in all lines under chilling conditions. In addition, a greater expression of ProDH2 and a lower expression of P5CDH were observed, leading us to speculate a greater breakdown of proline into P5C and a consequent overproduction of ROS in the ETC cycle. The higher POX and SOD activities and a higher MDA content in chs mutants at 13°C are in line with this speculation. Finally, cold-treated plants (4°C) only showed an increase in proline levels.