Kinetics Modelling of Pseudomonas stutzeri strain DN2 Growth Behaviour in Tributyltin Chloride

A predictive model was performed to describe Pseudomonas stutzeri strain DN2 growth behaviour in tributyltin chloride, using primary Modelling and a polynomial model as a secondary predictive model. In this investigation, data predicted using the modified Logistic (ML) was the most accurate. The Bias Factor (Bf) and Accuracy Factor (Af) values for the (ML) model were 1.39 and 1.51, indicating that the predictions were within a reliable range. The low RMSE value of 0.14, R2 and adj R2 (0.99) value closer to 1, showing that modified logistics is better than the other models at describing the growth behaviour of Pseudomonas stutzeri strain DN2 in toxic tributyltin chloride. Both the Aiba and Haldane models on the other hand, among the secondary model best fit the behaviours having low RMSE and MSE values and adjR2 value closer to 1. In this study, the primary and secondary kinetics of Pseudomonas stutzeri strain DN2 growth behaviour in tributyltin chloride was explored and it was shown in this study that the modified logistic and the Haldane models better suit the growth behavior of Pseudomonas stutzeri strain DN2 in tributyltin chloride. The parameters obtained from the modelling exercise will be very valuable in transferring the laboratory results to the field.

Tin-Naphthalene Sulfonic Acid Complexes as Photostabilizers for Poly(vinyl chloride)

Poly(vinyl chloride) degrades when exposed to ultraviolet light for long durations; therefore, the photostability of polymeric materials should be enhanced through the application of additives. New organotin complexes containing 4-aminonaphthalene-1-sulfonic acid were synthesized and their role as poly(vinyl chloride) photostabilizers were evaluated. The reaction of 4-amino-3-hydroxynaphthalene-1-sulfonic acid and appropriate di- or trisubstituted tin chloride (triphenyltin chloride, tributyltin chloride, dibutyltin dichloride, and dimethyltin dichloride) in methanol under reflux gave the corresponding tin-naphthalene complexes with yields of 75%–95%. Elemental analyses and spectroscopic techniques including infrared and nuclear magnetic resonance (proton and tin) were used to confirm their structures. The tin complexes were added to poly(vinyl chloride) to produce thin films that irradiated with ultraviolet light. Various parameters were assessed, such as the weight loss, formation of specific functional groups, changes in the surface due to photoirradiation, and rate constant of photodegradation, to test the role played by the organotin complexes to reduce photodegradation in polymeric films. The results proved that organotin complexes acted as photostabilizers in these circumstances. The weight loss, formation of fragments containing specific functional groups, and undesirable changes in the surface of polymeric films were limited in the presence of organotin complexes. Organotin complexes containing three phenyl groups showed the most desirable stabilization effect. These act as efficient primary and secondary photostabilizers, and as decomposers for peroxides. In addition, such an additive inhibits the dehydrochlorination process, which is the main cause of poly(vinyl chloride) photodegradation.

Acute Toxicity of Organotin on Fresh Water Shrimps and its Resistance by Marine Bacteria

This present study was aimed at investigating the acute toxicity of organotin on fresh water shrimps and its resistance to marine bacteria. 200 water shrimps were exposed to varying concentrations of Tributyltin Chloride (TBTCL) and Diphenyltin Chloride (DPTCL) for 96 hours and a probit was used to determine the lethal dose (LD50). 200g of sediment from Onne sea port Rivers State was manually polluted by TBTCL and DPTCL for 56 days. Organotin resistant bacteria were screened on mineral salt medium at different concentration of the organotin using the spread plate technique. Results from this study showed a lethal doze (LD50) of 4.24mg/l after 24 hours and 1.97mg/l after 48 hours for TBTCl on fresh water shrimps and a lethal doze of 21.05mg/l after 24 hours, 0.83mg/l after 48 hours and 0.006mg/l after 72 hours for DPTCl. The total viable count of bacteria obtained from varying concentrations of TBTCl indicates that approximately 65% of bacterial populations were resistant to 3.0mM of TBTCl and DPTCI since these isolates could grow on MSA supplemented with TBTCI and DPTCI. Statistically, there was no significant difference between the bacterial loads between the different concentrations of TBTCL. Acute toxicity effect of TBTCl and DPTCl on fresh water shrimps reveals TBTCl and DPTCl as one of the toxic substances in the marine ecosystem however; marine bacteria can be harnessed for their resistant abilities.

Histological study of gonadal tissues of adult Artemia salina (Linnaeus 1758) and immunohistochemistry by Caspase 3 and HSP70 to detect specific apoptosis markers on gonadal tissues after exposure to TBTCl

Background: Several types of research have been recently carried out on the biological effects of TBTs, including investigations of genitals in invertebrates in response to exposure to TBTs in marine water. Aim: The objective of this research was to investigate the acute effects of tributyltin chloride (TBTCl) on gonads in the adult stage of Artemia salina by use normal histology and immunohistochemistry (IHC) (Caspase 3 and HSP70) to see specific apoptosis markers. Methods: After exposure of A. salina to different concentrations of TBTCl (25, 50, 100, 200, and 300 ng.l−1), 50 adult A. salina (25 male and 25 female) were selected randomly from each concentration to histologically study the gonads. The gonad tissue was sectioned (5 μm) and some slides were stained with hematoxylin and eosin and others were stained with IHC avidin–biotin complex, and were examined under a light microscope. Results: The results showed significant differences (p < 0.05) in histological lesions between different concentrations of TBTCl. The histological lesions in the testis and ovary section were undifferentiated cells, degenerating yolk globules, and follicle cells enveloping the oocyte which was then compared with control tissue, and these effects were found to be increased in females more than in males with the highest concentration of TBTCl. Immunohistochemistry (IHC) showed that positive immunostaining was observed in the testis and ovary as brownish deposits to Caspase 3 and HSP70 antibody after exposure to TBTCl, while the testis and ovary section in control tissue had no immunoreactivity to Caspase 3 and HSP70 antibody; these effects were profoundly increased with the highest concentration of TBTCl in females more than in males. Finally, the histological lesions and IHC (Caspase 3 and HSP70) revealed that the apoptosis and immune system stress of A. salina gonad tissue damage in females were more sensitive to TBTCl toxicity as compared to white males. Conclusion: In general, the present study aimed to observe the effects TBTCl on A. salina gonads by using histological sections and IHC (Caspase 3 and HSP70), which were evaluated for the first time and have been proven to possess an important function in apoptosis marker and immune system stress in Artemia. Finally, the specific mechanisms through which TBTCl affects A. salina Caspase 3 and HSP70 expression need further investigation.

Metal load and oxidative stress driven by organotin compounds on rainbow trout

Tributyltin-based (TBT) antifouling paints, widely used for the treatment of flooded surfaces, have been banned in 2008 for their high environmental persistence and bioaccumulation in aquatic organisms. Although it is still present in aquatic ecosystems, oxidative stress driven by TBT has been still poorly investigated in fish. The aim of the study was to examine the time-course stress responses in liver of rainbow trout that received a single intraperitoneal injection of tributyltin chloride (TBTC) or tributyltin ethoxide (TBTE), both at a dose of 0.05 and 0.5 mg/kg. Levels of metallothioneins, total glutathione, malondialdehyde, superoxide dismutase, catalase, glutathione peroxidase and glutathione S-transferase were evaluated at 3 and 6 days post-injection. Tin load was measured in the muscle of the same fish. Differences were observed in the time-course accumulation of tin with a clear dose-response relationship. Although individual oxidative stress biomarkers varied, the biomarker profile indicated different stress mechanisms caused by both TBTC and TBTE. The weak induction of metal-trapping metallothioneins and the changes of oxidative stress biomarkers suggested a stress-pressure in both TBT-treated trout, advising for an ecotoxicological risk for freshwater ecosystems.

146 Tributyltin chloride exposure alters ejaculated bull sperm function and embryo development

Male exposure to environmental toxicants can disrupt spermatogenesis and impair sperm function. However, the consequences of environmentally relevant levels of toxicants to ejaculated mammalian spermatozoa on sperm function and male fertility are not well studied. Tributyltin chloride (TBT) is an organotin with historical use as an antifouling agent in paints and is a contaminant of soil and groundwater in the United States. Tributyltin chloride is an endocrine disruptor, is detectable in human cord blood, and has negative effects on female reproduction. We hypothesised that TBT could affect sperm function and thereby affect male fertility. To test our hypothesis, we exposed frozen-thawed bull sperm to environmentally relevant doses of TBT (0, 0.1, 1.0, 10, and 100nM) for 90min and then measured sperm motility parameters, fertilisation, and embryo development by IVF. Briefly, frozen-thawed sperm from two bulls were isolated through a 45:90 Percoll gradient, pooled, and then maintained in noncapacitating conditions at 37°C in Tyrode's albumin lactate pyruvate medium devoid of bovine serum albumin and HCO3 − for 90min. Vehicle control (VC) samples consisted of 0.1% MeOH. Sperm motility kinematics were objectively measured after the addition of treatment and every 30min thereafter using computer-aided sperm analysis (IVOS System, Hamilton Thorne). Five replicates were evaluated, and differences in motility kinematics were analysed by analysis of variance using SAS statistical software (SAS Institute Inc.). Sperm treated with 100nM TBT displayed decreased total motility (88 vs. 79%), progressive motility (80 vs. 70%), curvilinear velocity (100 vs. 88 µ/s), and beat-cross frequency (38 vs. 34Hz) over 90min compared with the VC samples (P&lt;0.05). No differences (P&gt;0.05) were detected among any other treatments. Following 90min of exposure to TBT 100nM, sperm were washed twice by centrifugation and re-extended in fertilisation medium. Abattoir-derived bovine oocytes were fertilised with 100nM TBT and VC-exposed sperm. Embryo cleavage and 8- to 16-cell embryos were quantified at 48 and 72h, respectively, in three replicates, and results were assessed using chi-square analysis. Embryos fertilised by TBT-exposed sperm had reduced cleavage to 2-cell (80 vs. 62%) and 8- to 16-cell morulae stages (56 vs. 24%, respectively; P&lt;0.05). In summary, although sperm kinematics were decreased in TBT-exposed sperm, gross motility parameters remained within acceptable ranges for IVF, suggesting that sperm motility alone is not a sufficient measure of sperm function or indicator of male fertility. In conclusion, ejaculated bull sperm exposed to environmentally relevant levels of TBT for 90min had reduced sperm motility parameters, impaired sperm function, and reduced embryo development potential. Research reported in this publication was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health under award number T32HD087166. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.