These data indicate that the presence of high levels of Cu/Zn SOD and Zn render spermatogonia resistant to ROS, and consequently protected from oxidative stress. These findings provide the biochemical basis for the high tolerance of spermatogonia to oxidative stress.
Also, knockdown of Cu/Zn SOD resulted in a reduction of Cu/Zn SOD-expressing germ cells, an increase in 8-OHdG-positive cells, and increased cell mortality. Thus, a deficiency of Cu/Zn SOD appears to be related to the high vulnerability of spermatogenic cells to oxidative stress. In Cu/Zn SOD-knockout mice exposed to heat stress, cleavage of DNA in spermatogenic cells was found to be elevated . Our experimental data demonstrates that Cu/Zn SOD is indeed a major factor in the high tolerance of spermatogonia to ROS.
Abstract:This study aims to examine the impact of social tolerance of cultural diversity, and the ability to speak widely spoken languages, on economic performance. Based on the literature, the evidence is still controversial and unclear. Therefore, the study used panel data relating to (99) non-English speaking economies during the time period between 2009 and 2017. Following the augmented Solow model approach, the related equation was expanded, in this study, to include (besides human capital) social tolerance, the English language (as a lingua franca) and the level of openness. The model was estimated using the two-step system GMM approach. The results show that social tolerance of diversity and English language competence have a positive, but insignificant impact on the economy. Regarding policy implications, government and decision-makers can avoid the costs deriving from cultural diversity by adopting democratic and effective institutions that aim to achieve cultural justice and recognition, which, in turn, enhance the level of tolerance, innovation and productivity in the economy. Moreover, to ease intercultural communication within heterogeneous communities, it is necessary to invest in enhancing the quality of second language education which is necessary to make society more tolerant and the country more open to the global economy.Keywords: economic growth; social tolerance; cultural diversity; English proficiency; human capital
Both the protein kinase SOS2 and its associated calcium-sensor subunit SOS3 are required for the posttranslational activation of SOS1 Na+/H+ exchange activity in Arabidopsis,(Qiu, Guo, Dietrich, Schumaker, & Zhu, 2002, Quintero, Martinez-Atienza, Villalta, Jiang, Kim, Ali, et al., 2011), and in rice (Martínez-Atienza, Jiang, Garciadeblas, Mendoza, Zhu, Pardo, et al., 2007). In yeast, co-expression of SOS1, SOS2, and SOS3 increases the salt tolerance of transformed yeast cells much more than expression of one or two SOS proteins (Quintero, Ohta, Shi, Zhu, & Pardo, 2002), suggesting that the full activity of SOS1 depends on the SOS2/SOS3 complex. Recently, SOS4 and SOS5 have also been characterized. SOS4 encodes a pyridoxal (PL) kinase that is involved in the biosynthesis of pyridoxal-5-phosphate (PLP), an active form of vitamin B6. SOS5 has been shown to be a putative cell surface adhesion protein that is required for normal cell expansion. Under salt stress, the normal growth and expansion of a plant cell becomes even more important and SOS5 helps in the maintenance of cell wall integrity and architecture (Mahajan, Pandey, & Tuteja, 2008).
Proline accumulation is due primarily to de novo synthesis associated with decreased oxidation and utilization, but increased transport processes are also likely involved (Aubert, Hennion, Bouchereau, Gout, Bligny, & Dorne, 1999, Flagella, Trono, Pompa, Di Fonzo, & Pastore, 2006, Kishor, Hong, Miao, Hu, & Verma, 1995). Proline accumulation occurs rapidly after the onset of stress and this supports the hypothesis that this accumulation is initially a reaction to salt stress and not a plant response associated with tolerance (Carillo, Mastrolonardo, Nacca, Parisi, Verlotta, & Fuggi, 2008, de Lacerda, Cambraia, Oliva, Ruiz, & Prisco, 2003). In addition to its role as an osmolyte for osmotic adjustment, proline contributes to stabilizing sub-cellular structures (e.g. membranes and proteins), scavenging free radicals, and buffering cellular redox potential under stress conditions. It may also function as a protein compatible hydrotrope (Srinivas & Balasubramanian, 1995), alleviating cytoplasmic acidosis, and maintaining appropriate NADP+/NADPH ratios compatible with metabolism (Hare & Cress, 1997). Also, rapid breakdown of proline upon relief of stress may provide sufficient reducing agents that support mitochondrial oxidative phosphorylation and generation of ATP for recovery from stress and repairing of stress-induced damages (Carillo, Mastrolonardo, Nacca, Parisi, Verlotta, & Fuggi, 2008, Hare & Cress, 1997). Furthermore, proline is known to induce expression of salt stress responsive genes, which possess proline responsive elements (e.g. PRE, ACTCAT) in their promoters (Ashraf & Foolad, 2007, Chinnusamy, Jagendorf, & Zhu, 2005).
Overexpression of regulatory genes in signalling pathways, such as transcription factors (DREB/CBF) and protein kinases (MAPK, CDPK) also increases plant salt tolerance (Chen, Ren, Zhong, Jiang, & Li, 2010). The overexpression of the vacuolar Na+/H+ antiport has shown to improve salinity tolerance in several plants (Silva & Gerós, 2009). The first evidence showed that the overexpression of AtNHX1 in Arabidopsis plants promoted sustained growth and development in soil watered with up to 200 mM NaCl (Apse, Aharon, Snedden, & Blumwald, 1999), although recent evidences report that transgenic Arabidopsis do not show a significantly improved salt tolerance as compared to that of control plants (Yang, et al., 2009). In addition, transgenic tomato plants overexpressing AtNHX1 were able to grow, flower and produce fruit in the presence of 200 mM NaCl (H.-X. Zhang, Hodson, Williams, & Blumwald, 2001, H. Zhang & Blumwald, 2001). Also, transgenic tobacco plants overexpressing GhNHX1 from cotton and transgenic rice overexpressing the Na+/H+ antiporter gene clone from OsNHX1 exhibited higher salt tolerance (Fukuda, Nakamura, Tagiri, Tanaka, Miyao, Hirochika, et al., 2004, Wu, Yang, Meng, & Zheng, 2004). Overexpression of AtNHX1 in Petunia hybrida enhanced salt and drought tolerance in this plant, which accumulated more Na+, K+, and proline in their leaf tissue than that of the WT Petunia plants, maintaining high water contents and high ratio of K+/Na+ (Xu, Hong, Luo, & Xia, 2009). By introgressing Nax genes from Triticum monococcum into hexaploid bread wheat (Triticum aestivum), the leaf blade Na+ concentration was reduced by 60% and the proportion of Na+ stored in leaf sheaths was increased. The results indicate that Nax genes have the potential to improve the salt tolerance of bread wheat (Richard A. James, Blake, Byrt, & Munns, 2011). The increased expression in tomato and rice of Arabidopsis Arginine Vasopressin 1 (AVP1), encoding a vacuolar pyrophosphatase acting as a proton pump on the vacuolar membrane, enhanced sequestering of ions and sugars into the vacuole, reducing water potential and resulting in increased salt tolerance when compared to wild-type plants (Pasapula, Shen, Kuppu, Paez-Valencia, Mendoza, Hou, et al., 2011). Furthermore, overexpression of genes encoding Late Embryogenesis Abundant (LEA) proteins, which accumulate to high levels during seed development, such as the barley HVA1 (Xu et al., 1996) and wheat dehydrin DHN-5 (Brini et al., 2007), can enhance plant salt tolerance, although their function is obscure. 2b1af7f3a8