Bioindicator potential of Spathosternum prasiniferum prasiniferum (Orthoptera; Acridoidea) in pesticide (azadirachtin)-induced radical toxicity in gonadal/nymphal tissues; correlation with eco-sustainability

Acridids are highly abundant living-organism/major-component in agricultural field, globally. It may act as a dependable bio-indicator species in response to environmental-stress. Antioxidants protect insects by scavenging free radicals. Here, we investigated the dose dependant azadirachtin (C₃₅H₄₄O₁₆ AZT) toxicity on oxidative-biomarker; Alkaline-phosphatase (ALP), malondialdehyde (MDA), non-protein-soluble-thiol (NPSH) and antioxidants like superoxide-dismutase (SOD), catalase (CAT), glutathione-peroxidase (GPx) and amylase of gonads from both sexes and juvenile tissues of common grasshopper, Spathosternum prasiniferum prasiniferum (Walker, 1871). The newly hatched adults (female: male = 1:1) are exposed to 1 to 20 ppm AZT for 48 h and have compared to control and 6 h incubation with same concentration of azadirachtin for in vitro experiments. Both in vivo and in vitro experiment demonstrated significant influences on oxidative biomarkers with increasing antioxidant enzymatic activities in either sex. The male gonads represents decreasing antioxidant enzyme activities compared to female gonads. Lesser protection by CAT and SOD are noticed in male than female in response to AZT exposure. This experiment suggests that azadirachtin increased the major biomarkers with decreasing antioxidant enzyme activities resulting in more free-radicals related threat in adult male gonads. Variable dose responses were noticed on ALP, AchE and MDA in either gender suggesting multiphasic action of the pesticides. Higher mortality rate is noticed in male with lower nymphal life span. Moreover, nymph II^nd is more susceptible than nymph IV^th in vitro intoxication of azadirachtin. Possible life threat of vast representatives of agricultural ecosystem by pesticide should be avoided to maintain different bio-geo cycle and eco-sustainability.     

多巴胺(DA)和去甲肾上腺素(NE)在文昌鱼神经系统和性腺中的免疫细胞化学定位

用免疫细胞化学ABC法对多巴胺（DA）和去甲肾上腺素（ＮＥ）的文昌鱼神经系统和性腺中进行定位研究。免疫反应结果显示：ＤＡ和ＮＥ免疫阳性神经细胞广泛分布在文昌鱼端脑后部、中脑前部和中部以及脊髓,我们还观察到,在文昌鱼漏斗部也有ＤＡ免疫阳性神经细胞及其纤维;在中脑中部,ＮＥ免疫阳性神经细胞及其纤维与另一个神经细胞相接触。此餐,文昌鱼精巢和卵巢中也存在ＤＡ和ＮＥ免疫阳性物,研究结果表明,ＤＡ和ＮＥ可有像在鱼类中那样,参与调节文昌鱼哈氏窝上皮细胞的分泌活动以及性腺发育。     

PAP7, a PBR/PKA-RIα-associated protein: a new element in the relay of the hormonal induction of steroidogenesis

The precise mechanism by which the hormone-induced minimal cAMP levels act at the mitochondria to activate cholesterol transport and steroid synthesis is unknown. We propose that this mechanism involves a macromolecular signaling complex where a newly identified peripheral-type benzodiazepine receptor (PBR)-associated protein (PAP7) binds the regulatory subunit RIα of the cAMP-dependent protein kinase A (PKA), thus allowing for local efficient catalytic activation and phosphorylation of the substrate steroidogenesis acute regulatory protein (StAR), leading to cholesterol transfer from the low affinity StAR to the high affinity PBR cholesterol binding protein. The mouse and human PAP7 proteins were cloned, their genomic organization and chromosomal localization characterized, their tissue distribution evaluated and subcellular localization defined. PAP7 is highly expressed in steroidogenic tissues, where it follows the pattern of PKA-RIα expression and data from a human adrenal disease suggest that it participates in PKA-RIα-mediated tumorigenesis and hormone-independent hypercortisolism. PAP7 is localized in the Golgi and mitochondria and inhibition of PAP7 expression results in reduced hormone-induced cholesterol transport into mitochondria and decreased steroid formation. Taken together, these data suggest that PAP7 functions as an A-kinase anchoring protein (AKAP) critical in the cAMP-dependent steroid formation.     

Environmental regulation of the reproductive system in a flexibly breeding Sonoran Desert bird, the Rufous-winged Sparrow, Aimophila carpalis

We investigated reproductive regulation in male Rufous-winged Sparrows, Aimophila carpalis, a Sonoran Desert passerine that breeds after irregular summer rains. Field and captive data demonstrate that increased photoperiod stimulates testicular development in March and maintains it until early September. Free-living birds caught in July and placed on captive long days (16L: 8D) maintained developed testes for up to 7 months, and free-living birds caught in September, during testicular regression, redeveloped testes when placed on captive long days, indicating that these birds were still photosensitive. Captive birds on long days maintained testicular development when exposed to temperatures mimicking those occurring during regression in free-living birds. In free-living birds, testicular development was observed during spring and summer, but unless this was associated with rainfall, breeding (indicated by juveniles) did not occur. Large increases in plasma luteinizing hormone (LH) in free-living males were correlated with heavy rainfall in July/August, when the birds bred, and in November, when they did not breed. In captive birds, plasma LH concentrations were unresponsive to photoperiodic changes, but may have responded to social cues. Plasma prolactin concentrations were directly correlated with photoperiod in free-living birds, but an effect of photoperiod on prolactin secretion was not seen in captive birds. It is concluded that male Rufous-winged Sparrows use long photoperiods to stimulate and maintain testicular development, but exposure to long photoperiods does not terminate breeding by inducing absolute photorefractoriness. The specific timing of reproductive behaviors is apparently determined by elevated plasma LH coinciding with long day stimulated gonad development.     

Molecular cloning of DAX1 and SHP cDNAs and their expression patterns in the Nile tilapia,Oreochromis niloticus

Piscine DAX1 and SHP cDNAs with an open reading frame encoding 296 and 258 amino acid residues, respectively, as well as SHP partial gene fragment, were cloned from Nile tilapia. Phylogenetic analyses of DAX1s, SHPs, and homologous EST fragments indicate that DAX1 and SHP are conserved in gene structure and are present throughout vertebrates. A single band of approximately 1.4kb for DAX1 and of approximately 1.2kb for SHP was detected in the Northern blot analysis. Tissue distribution analysis by RT-PCR showed that fish DAX1 and SHP mRNAs are widely expressed in adult tissues, with the most abundant expression in gonads and liver, respectively. DAX1 and SHP were also detected in gonads of both sexes at 5-90 days after hatching (dah). However, the expression of DAX1 is weak at 5 and 10dah and then significantly up-regulated between 10 and 15dah, whereas the expression of SHP is moderate and consistent during the ontogeny.     

Characterization of aspartate transcarbamylase activity from gonads of the soft shell clam,Mya arenaria

Aspartate transcarbamylase (ATCase, EC 2.1.3.2) has been shown to be a good index of the reproductive cycle in marine molluscs. However, this enzyme has never been studied in the soft shell clam Mya arenaria. The characteristics of gonadal ATCase of the soft shell clam, Mya arenaria were therefore determined since we need powerful tools to assess the degree of effects of endocrine disruptors in this species at risk. Enzyme kinetic values observed at pH 8.3 were significantly lower than those measured at pH 9.4. The optimal conditions for the enzyme assays were reached in the presence of a 10 mM of substrate concentration and at pH 9.2 for 60 min at 37 °C. We have found that the enzyme was heat sensitive, markedly activated by DMSO and DMF, but no effect was observed with ethanol, ATP or CTP. However, clam ATCase activity was partly inhibited by the addition of CuSO₄ and PHMB to the medium, an inhibition that could be attributed to the presence of SH sites in cysteine residues localized in the catalytic site of this enzyme. All these results will be very useful in the near future to study the gametogenetic process of Mya arenaria, since little is known about the factors that control the physiological process of reproduction in this bivalve of ecological and economic importance. Studies of variations of the activity of aspartate transcarbamylase will also be useful as a potential biomarker to evaluate the disruption of gametogenesis in clams exposed to endocrine disruptors in situ.     

Tissue-cell- and species-specific expression of gonadotropin-regulated long chain acyl-CoA synthetase (GR-LACS) in gonads, adrenal and brain. Identification of novel forms in the brain

Gonadotropin-regulated long chain acyl-CoA synthetase (GR-LACS) is a novel hormonally regulated fatty acyl-CoA synthetase (FACS) with activity for long-chain fatty acids. The presence of this enzyme in the Leydig cells of the mature rat testis and its mode of regulation suggest that it participates in testicular steroidogenesis. This study demonstrates that GR-LACS expression is tissue, cell and species-specific. The 79 kDa GR-LACS protein is expressed in rodent gonads and brain, and only in the mouse in the adrenal cortex. In the ovary of both species it is associated with follicles undergoing atresia. It is present in the newborn and immature testis tubules and after puberty only in the Leydig cells. A distinct GR-LACS protein species of 64 kDa that was more abundant than the 79 kDa long form was found in the rat brain. Also, a minor 73 kDa form was observed in the rat brain and mouse ovary. Two novel species resulting from alternatively splicing of the GR-LACS gene were identified in a rat brain cDNA library: a short form 1 (S1) lacking exon 8 and short form 2 (S2) lacking exons 6–8. Expression studies revealed that the sizes of the S1/S2 proteins are comparable to those of the endogenous variant species. Neither S form contains FACSs activity, suggesting that exon 8 is essential for the enzymatic function. GR-LACS variants exhibit small but significant dominant negative effects on the FACS activity of the long form. GR-LACS variants may regulate the long form's activity in the brain.     

高原鼠兔季节性繁殖中的神经内分泌调控Ⅱ．不同光制对生殖恢复期的影响

本项研究将野外捕获的成年雄性高原鼠兔（Ｏｃｈｏｔｏｎａｃｕｒｚｏｎｉａｅ）分３组进行不同光制的饲养,以检验光周期对其神经内分泌─—生殖轴功能的影响：（１）长光照组睾丸及附属性腺的重量和血浆睾酮水平均明显高于自然光组（ｐ＜０．０５）和短光照组（ｐ＜０．０１）。（２）长光照组的松果腺重量（１．５±０．１毫克,ｎ＝１５）和褪黑激素含量（８９．７±５．８微微克／松果腺）,均显著低于其它两组。（３）自然光组和短光照组性腺的显著萌发表明,在高原鼠兔季节性繁殖的年周期中,其神经内分泌─—生殖轴对春分前短光照的抑制作用具有不应期。