Nutrient additions to seagrass seed planting improve seedling emergence and growth

To maximize the opportunities of seagrass as a nature-based solution requires restoration to occur on a large scale. New methods and knowledge are required that can solve ecological bottlenecks, improving its reliability and effectiveness. Although there is increasing interest in the use of seeds for seagrass restoration there exists a limited understanding of how best to plant them with the most knowledge on germination and seedling emergence coming from laboratory studies. Here we present the results of a novel field study on the emergence success of seeds of the seagrass Zostera marina when subjected to varied planting treatments. Seeds were planted into hessian bags according to a factorial design of three treatments (sediment type, detritus addition, and nutrient addition). By adding nutrients to natural sediment, the present study provides some evidence of seagrass shoot emergence and maximum shoot length doubling. The present study provides evidence that even in heavily nutrient-rich environments, seagrass sediments may require additional nutrients to improve seedling emergence and growth. It also highlights the highly variable nature of planting seagrass seeds in shallow coastal environments. Critically this study provides increasing levels of evidence that small subtleties in the method can have large consequences for seagrass restoration and that for restoration to scale to levels that are relevant for nature-based solutions there remain many unknowns that require consideration.

Survivors of childhood leukaemia treated with haematopoietic stem cell transplantation and total body irradiation should undergo screening for diabetes by oral glucose tolerance tests

AIMS

Childhood cancer survivors treated with haematopoietic stem cell transplantation (HSCT) and total body irradiation are at an increased risk of developing diabetes early in life due to insulin resistance and β-cell dysfunction, but the optimal screening method is unknown. The National Institute for Health and Care Excellence guidelines for community diabetes screening recommend using fasting glucose ≥ 7 mmol/l and/or HbA1c ≥ 48 mmol/mol (6.5%) for diagnosis and, fasting glucose 5.5-6.9 mmol/l or HbA1c 42-47 mmol/mol (6-6.5%) to indicate high risk. This study aimed to evaluate the sensitivities of fasting glucose and HbA1c in the diagnosis of diabetes and impaired glucose tolerance in childhood HSCT survivors.

METHOD

The patients were 35 (male = 19) HSCT survivors from a single UK centre under follow-up from 2006 to 2013. Patients had a median age (range) of 19.2 (13.1-26.2) years and had been treated for acute lymphoblastic (n = 31) or myeloid (n = 4) leukaemia when aged 7.8 (2.4-16.7) years. The outcome measures were oral glucose tolerance test (OGTT), fasting glucose and HbA1c .

RESULTS

OGTT identified 6 patients with diabetes (120-min glucose ≥ 11.1 mmol/l), 12 with impaired glucose tolerance (120-min glucose 7.8-11.0 mmol/l) and 2 with impaired fasting glucose (≥ 7 mmol/l). Fasting glucose ≥ 7 mmol/l or HbA1c ≥ 48 mmol/mol identified two of the six patients with diabetes diagnosed on OGTT. Fasting glucose ≥ 5.5 mmol/l and HbA1c ≥ 42 mmol/mol identified three and two patients, respectively, with diabetes. Only 1 of 12 patients with impaired glucose tolerance had a fasting glucose ≥ 5.5 mmol/l and none had HbA1c ≥ 42 mmol/mol (≥ 6%).

CONCLUSIONS

The fasting glucose and HbA1c cut-offs used in UK population screening only identified one-third of HSCT survivors with diabetes and do not identify those at risk. Diabetes screening in HSCT survivors requires standard OGTTs.

Tissue-specific regulation of sialyltransferase activities in the rat by corticosteroids in vivo

In this study we have examined the effects of corticosteroids on both the total sialyltransferase (sialyl-T) activity and on two individual isozymes in neural, hepatic, and renal tissues using an in vivo model system. Rats were adrenalectomised to deplete their endogenous stores of steroid hormones, and some subsequently received steroid replacement with dexamethasone or aldosterone. Adrenalectomy resulted in a significant decrease in total neural sialyl-T activity when compared with sham-operated animals in the four brain regions examined, indicating that total sialyl-T activity is normally under positive corticosteroid control. The subsequent effects of exogenous corticosteroids exhibited regional specificity with the enzyme activities in the cortex, cerebellum, and brainstem being stimulated by both dexamethasone and aldosterone and enzyme activity in the hippocampus being stimulated by aldosterone alone. In general, the changes in total enzyme activity could be attributed to the alpha 2,6 sialyl-T isozyme, although the changes in the cerebellum appeared to coincide with alpha 2,3 sialyl-T activity. In the liver, adrenalectomy resulted in an increase in enzyme activity which was not altered by administration of corticosteroids. There were no changes in total renal sialyl-T activity in any of the four experimental groups although certain changes were observed at the level of individual sialyl-T isozymes. These results demonstrate that sialyl-T activity in certain tissues is under the control of corticosteroids and that this is both a tissue-specific and region-specific effect.