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Background and aims
The effects of salt stress on the salt marsh halophyte Spartina alterniflora have been well documented. However, plant responses to combined salinity and ammonium toxicity and the underlying mechanisms are relatively unknown. The aim of the present investigation was to study the effects of both salinity (0, 200 and 500 mM NaCl) and nitrogen form (NO3 ?, NH4 + or NH4NO3) on S. alterniflora.Methods
Plants were cultivated in sandy soil under greenhouse conditions for 3 months. At harvest, growth parameters were measured and leaf samples were analysed for oxidative stress parameters (malondialdehyde, MDA; electrolyte leakage, EL; and hydrogen peroxide, H2O2 concentration) and the activity of antioxidant enzymes (glutathione reductase, GR; superoxide dismutase, SOD; catalase, CAT; ascorbate peroxidase, APX and Guaiacol peroxidase, GPX).Results
In the absence of NaCl, plant growth rate was the highest in the medium containing both nitrogen forms, and the lowest in the medium containing only nitrate. Irrespective of the nitrogen form, plant growth was generally higher at 200 mM NaCl than without salinity. Ammonium-fed plants showed better growth than nitrate-fed plants under high salinity. In the absence of salinity, ammonium-fed plants showed higher SOD, APX, GR, CAT, and GPX activities than nitrate-fed ones. The antioxidant enzymes exhibited higher activity in saline-treated plants. The considerable advantage of NH4 + nutrition to S. alterniflora under saline conditions was associated with high antioxidant enzyme activities, together with low MDA content, EL, and H2O2 concentration.Conclusion
These data clearly demonstrate that NH4 + is more favourable for the growth of S. alterniflora under high salinity than NO3 ?. It is suggested that NH4 + nutrition improves the plant’s capacity to limit oxidative damage by stimulating the activities of the major antioxidant enzymes. 相似文献2. This study aimed to determine whether or not this effect is due to females using nutrients from the nuptial gift (spermatophore and spermatophylax) to manufacture more eggs in the bushcricket Leptophyes punctatissima .
3. Females were permitted either a single or a double mating (with two different males) and, in both mating categories, were either prevented from consuming any part of the spermatophore or were permitted to consume the entire spermatophore.
4. Doubly mated females were found to lay over twice as many eggs over a 4-week period compared with singly mated females. This difference did not appear to be caused by the consumption of extra nuptial gift material: mating was found to have a significant positive effect on the number of eggs laid, while nuptial gift feeding had no effect. 相似文献
Familial adenomatous polyposis (known also as classical or severe FAP) is a rare autosomal dominant colorectal cancer predisposition syndrome, characterized by the presence of hundreds to thousands of adenomatous polyps in the colon and rectum from an early age. In the absence of prophylactic surgery, colorectal cancer (CRC) is the inevitable consequence of FAP. The vast majority of FAP is caused by germline mutations in the adenomatous polyposis coli (APC) tumor suppressor gene (5q21). To date, most of the germline mutations in classical FAP result in truncation of the APC protein and 60% are mainly located within exon 15.
Material and methodsIn this first nationwide study, we investigated the clinical and genetic features of 52 unrelated Algerian FAP families. We screened by PCR-direct sequencing the entire exon 15 of APC gene in 50 families and two families have been analyzed by NGS using a cancer panel of 30 hereditary cancer genes.
ResultsAmong 52 FAP index cases, 36 had 100 or more than 100 polyps, 37 had strong family history of FAP, 5 developed desmoids tumors, 15 had extra colonic manifestations and 21 had colorectal cancer. We detected 13 distinct germline mutations in 17 FAP families. Interestingly, 4 novel APC germline pathogenic variants never described before have been identified in our study.
ConclusionsThe accumulating knowledge about the prevalence and nature of APC variants in Algerian population will contribute in the near future to the implementation of genetic testing and counseling for FAP patients.
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