Soil salinity affects the expression of serine/arginine-rich (SR) genes and isoforms by alternative splicing, which in turn regulates the adaptation of plants to stress.  We previously identified the cassava spliceosomal component 35 like (SCL) and SR subfamilies, belonging to the SR protein family, which are extensively involved in responses to abiotic stresses.  However, the post-transcriptional regulatory mechanism of cassava arginine/serine-rich (RS) subfamily in response to salt stress remains to be explored.  In the current study, we identified 37 genes of the RS subfamily from 11 plant species and systematically investigated the transcript levels of the RS40 and RS31 genes under diverse abiotic stress conditions.  Subsequently, an analysis of the conserved protein domains revealed that plant RS subfamily genes were likely to preserve their conserved molecular functions and played critical functional roles in responses to abiotic stresses.  Importantly, we found that overexpression of MeRS40 in Arabidopsis enhanced salt tolerance by maintaining reactive oxygen species homeostasis and up-regulating the salt-responsive genes.  However, overexpression of MeRS40 gene in cassava reduced salt tolerance due to the depression of its endogenous gene expression by negative autoregulation of its own pre-mRNA.  Moreover, the MeRS40 protein interacted with MeU1-70Ks (MeU1-70Ka and MeU1-70Kb) in vivo and in vitro, respectively.  Therefore, our findings highlight the critical role of cassava SR proteins in responses to salt stress in plants. 

Sucrose is known to play an important role in the cryopreservation of sperm and female gonads; however, its effect on the cryopreservation of pig spermatogonial stem cells (pSSCs) has not been tested.  The aim of this work was to study the effect of sucrose during pSSC cryopreservation and to find the most effective concentration in freezing medium.  pSSCs were cryopreserved with freezing media containing different concentrations of sucrose (70, 140, 210, and 280 mmol L^–1) and a control group without sucrose.  The survival rates, plasma membrane integrity, and mitochondrial membrane potential of thawed cells were detected by trypan blue (TB) staining, SYBR-14/propidium iodide (PI) dual staining, and JC-1 staining, respectively.  All the staining results showed an obvious increase in cell survival in the sucrose-treated groups as compared to that in the control group, with the exception of 280 mmol L^–1 sucrose.  Moreover, the 210 mmol L^–1 sucrose group yielded the highest survival rate among all the groups (P<0.05).  The results of SYBR-14/PI dual staining and JC-1 staining were consistent with those of TB staining as above described.  Quantitative real-time PCR (qRT-PCR) indicated that the mRNA levels of three apoptosis-promoting genes (BAX, APAF1 and CASPASE9) were significantly higher in thawed cells than in cells before freezing (P<0.05).  Moreover, the mRNA level of one anti-apoptotic gene (XIAP) was significantly lower in thawed cells than in cells before freezing (P<0.05).  When comparing the mRNA expression of apoptosis-related genes in thawed cells, the mRNA level of the anti-apoptotic genes in the control group was significantly lower than that in the sucrose-treated
groups (P<0.05).  Western blot analyses showed that the expression levels of cleaved CASPASE9, CASPASE3 and PARP-1 in the sucrose-treated groups were lower than those in the control group and were the lowest in the 210 mmol L^–1 sucrose group.  Both qRT-PCR and Western blot analyses suggested that sucrose inhibited cell apoptosis during freezing and thawing.  Briefly, sucrose promoted pSSCs survival after freezing and thawing, especially at a concentration of 210 mmol L^–1, which possibly assisted pSSC dehydration and inhibited cell apoptosis.  These findings hold great promise for further studies of the regulatory mechanism of proliferation and differentiation of pSSCs. 

This article analyses the technical and environmental efficiency of hog production in China using data from the China Agricultural Product Cost-Benefit Compilation (NDRC 2005–2013) and the First National Census of Pollution: Manual of Discharge Coefficient of Livestock and Poultry Industry (IEDA and NIES 2009). The empirical results show a great variation in environmental efficiency, ranging from 0.344 to 0.973 with a mean value of 0.672 that declines over time. Southwest China is found to be the most environmentally efficient region, while the Northeast and the Northwest are the least efficient. Another finding is that technical and environmental efficiencies are highly correlated in hog production; the most environmentally efficient regions are usually found to have high technical efficiency, and vice versa. In addition, we computed the output elasticities with respect to each factor input. The results show that feed is the most efficient input, with an output elasticity of approximately 0.551, which is much higher than the elasticity of the nitrogen surplus, other capital or labour. The output elasticity with respect to the nitrogen surplus is 0.287 on average. Finally, the scale elasticity in hog production is slightly higher than 1.

In cucumber, fruit shape is an important quality criterion, and fruit bending is known to limit growth, yield, and taste. To investigate the post-transcriptional changes that regulate fruit bending and to better understand the underlying molecular mechanisms, we generated a proteomic profile of the abdomen and back of cucumber bending fruit. Two-dimensional gel electrophoresis (2-DE) allowed the detection of approximately 900 distinct protein spots in each gel, 32 of which were differentially expressed in the abdomen and back of bending cucumber fruit. Ten of the differentially expressed proteins were analyzed using matrix-assisted laser ionization time of flight mass spectrometry (MALDI-TOF/MS). A search of primary databases showed that the identified proteins are involved in various metabolic processes and cellular responses, including photosynthesis metabolism, energy metabolism, defense and stress response, and regulation. The identified proteins included large subunits of ribulose-1,5-bisphosphate carboxylase/oxygenase, which are involved in photosynthesis and photorespiratory metabolism, and isocitrate dehydrogenase, which is involved in the tricarboxylic acid cycle. It is possible that imbalances in catabolic and anabolic processes directly affect the bending of cucumber fruit. The predicted function of the cobalamin- independent methionine synthase isozyme is closely related to ethylene biosynthesis; fruit bending may be regulated by ethylene, or by ethylene signaling crosstalk during fruit development. The 14-3-3 protein is usually considered to be a regulation-related protein, which plays a role in regulating cell hyperplasia, cell differentiation during growth, and apoptosis during senescence. Involvement of guanosine triphosphate (GTP)-binding proteins in signal transmission is known to regulate the development of cells in cucumber fruits and to play a role in fruit shape variation. Patterns of protein expression showed high repeatability. We hypothesize that these proteins may play an important role in growth and bending of cucumber fruits. The results of our study provide insight into the genetic mechanism underlying fruit bending in cucumber, and may help to promote cultivation of new varieties with superior fruits.

Ser/Arg-rich (SR) genes encode proteins that play pivotal roles in both constitutive and alternative splicing of pre-mRNA. However, not much effort has been made to investigate the alternative splicing of their own pre-mRNA. In this study, we conducted comprehensive analyses of pre-mRNA splicing for 22 SR genes in three rice (Oryza sativa L.) ecotypes indica, japonica and javanica. Using different ecotypes we characterized the variations in expression and splicing patterns of rice SR genes in different tissues and at different developmental stages. In addition, we compared the divergence in expression and splicing patterns of SR genes from seedlings of different rice ecotypes in response to hormones application and environmental stresses. Our results revealed the complexity of alternative splicing of SR genes in rice. The splicing varies in different tissues, in different ecotypes, in response to stresses and hormones. Thus, our study suggested that SR genes were subjected to sophisticated alternative splicing although their encoding proteins were involved in the splicing process.