Molecular characterization of phosphate solubilizing fungi Aspergillus niger and its correlation to sustainable agriculture

Aim: The present study aimed to investigate the phosphate solubilization potential of agriculturally important fungi, i.e., Aspergillus sp. isolated from the rhizosphere of healthy plants in Abha city, Saudi Arabia.Methodology: Sixteen Aspergillus sp. isolated and tested for phosphate solubilization potential were identified by 5.8S-ITS region sequencing and characterized by 11 ISSR-PCR markers. Finally, the highest phosphate solubilization potential isolates were used in field experiments on cucumber and tomato plants. Results: All Aspergillus niger isolates showed 96–100% similarity to A. niger strains available at GenBank database, Isolate ASAB-5 was most efficient at solubilizing phosphate on Pikovskaya’s medium, with a solubilization index of 2.67, and 235.22 mg l-1 of solubilized phosphate. ISSR-PCR markers revealed is total 142 bands in all isolates, with about 32.3% showing monomorphism and 67.6% polymorphism. Based on genetic similarity and intraspecies variability, the Aspergillus isolates were grouped into two different clusters with about 67.9% genetic similarity. The results of field experiments showed no significant difference between seeds treated with culture filtrate or conidial suspension of ASAB-5; however, both differed remarkably from untreated seeds. Interpretation: The current study confirms the existence of several useful phosphate solubilizing fungi in plants, which may serve as potential biological fertilizers. They are safer than chemical fertilizers and increase the bioavailability of soil phosphates for plants

Captopril and / or melatonin attenuates diabetes induced metabolic disorders and oxidative stress in rats

There is a clear link between diabetes, metabolic disorders and oxidative stress. Hyperglycemia leads to hyperlipidemia, renal dysfunction, free radical generation and alteration of endogenous antioxidants. The present study is an attempt to evaluate the possible protective effect of captopril [CAP] and/or melatonin [MLT] against Streptozotocin [STZ]-induced metabolic disorders, renal dysfunction and oxidative stress in rats. STZ challenge induced diabetic model that was characterized biochemically and histologically. Serum glucose, lipid profile, creatinine, urea, pancreatic tissue contents of glutathione [GSH] and malondialdehyde [MDA] as well as pancreatic catalase [CAT] and superoxide dismutase [SOD] activities were determined. CAP and/or MLT were given in a dose of [10 mg/ kg/day p.o.] for 10 consecutive days prior to STZ [60 mg/ kg as a single dose] treatment followed by 30 consecutive days in previous dose regimen. Results revealed that STZ induced a marked increase in serum glucose, serum triglycerides [TG], total cholesterol [TC] and LDL-cholesterol as well as serum creatinine and urea. On the contrary HDL-cholesterol was markedly decreased in STZ-treated group. Moreover, STZ induced significant decrease in the pancreatic content of GSH and SOD with concomitant increase in MDA content. Administration of CAP or [CAP plus MLT] prior to STZ treatment revealed a marked decrease in serum glucose, TC, TG and LDL as compared to STZ-treated group. Furthermore, treatment with CAP and MLT decreased the elevated serum levels of creatinine and urea. On opposite direction, CAP, MLT and their combinations were significantly increased pancreatic GSH content and SOD activity while decreases pancreatic MDA content when compared to STZ- alone. The biochemical observations were further confirmed histologically. STZ induced degenerative, necrotic changes in the islets of langerhans of pancreas and leukocytic infiltration. Pancreatic degenerative changes were improved by treatment with CAP and MLT. These results confirm that administration of CAP and/or MLT decrease STZ-induced metabolic disorders probably via regulation of oxidant / anti-oxidant balance and by modulation of hyperlipidemia associated with STZ-induced diabetes in rats. CAP, MLT and their combinations presumably due to their antioxidant, free radicals scavenging activity and hypolipidemic effects is highly protective against the biochemical and histopathological changes associated with STZ-induced diabetes

Effect of praziquantel on the hosf-tissue contents of calcium, magnesium, copper and zinc in S. mansoni infected mice

The effect of praziquantel [500 mg/kg/day for 2 consecutive days] on host-tissue content of calcium; magnesium; copper and zinc was investigated in Schistosoma mansoni-infected mice. Also, the drug effect in normal healthy mice was studied. Praziquantel caused significant increase in Ca content of the liver, kidneys and gastrocnemius muscle of both infected and healthy mice 24 hours after its administration, in comparison with the corresponding non-treated control groups. Also, the drug increased the Ca content of both heart and spleen of the infected animals at the same time period. Seven days latter, there was significant increase in the liver, spleen and muscle Ca of the infected treated mice together with a reduction in kidney Ca content. However, in healthy mice, the drug did not cause any change in tissue Ca content after 7 days of its administration. On the other hand, the drug had no effect on tissue content of Mg; Cu and Zn after 24 hours of treatment of both S. mansoni-infected and normal healthy animals. Also, after 7 days of its administration, it had no effect on the three cations in normal healthy mice. However, in the infected group, there was marked increase in the liver content of Mg, Cu and Zn. Also spleen and muscle Mg were increased. On the contrary, kidney Mg and Zn as well as spleen Cu were decreased. These results might reflect the modulatory action of praziquantel on cell membrane permeability to Ca[++] as well as its high curative activity resulting in relatively rapid resolution of cellular reactions and fibrosis of infected tissues