Many ultraviolet-A (UVA)-induced biochemical
and physiological changes are valid as
biomarkers using aquatic species for detection of the
degree of stress. Changes in the concentration and
activities of enzymes, such as glucose-6-phosphate
dehyderogenase (G6PDH), lactate dehyderogenase
(LDH), DNA damage and lipid peroxidation (LPO),
can be used as biomarkers to identify possible
environmental contamination in fish. This study
aimed to investigate the impact of UVA on the
activity of the selected enzymes, DNA damage and
LPO during early developmental stages of the African
catfish Clarias gariepinus. Embryo hemogenates were
used for measurements of G6PDH, LDH, DNA
damage and LPO concentrations and activities spectrophotometrically
at 37C. The normal ontogenetic
variations in enzyme activities, DNA damage and
LPO of the early developmental stages (24–168
h-PFS; hours-post fertilization stage) were studied.
There was a significant decrease in the activity of
G6PDH till 120 h-PFS. Then after 120 h-PFS, the
activity of such enzymes insignificantly increased
toward higher stages. The LDH activity was recorded
with a pattern of decrease till 96 h-PFS, followed by a
significant increase toward 168 h-PFS. The polynomial
pattern of variations in DNA damage and LPO
was also evident. The patterns of the enzyme activities,
corresponding DNA damage and LPO of the
early ontogenetic stages under the influence of three
different UVA doses (15, 30 and 60 min), were
recorded. The pattern of variations in G6PDH activity
in UVA-induced groups was similar to that of the
control group with variation in the magnitude of such
activity. In all treated groups, LDH activity decreased
till 96 h-PFS, then increased till 168 h-PFS. Within
each of the embryonic stages, the increase in UVA led
to a significant increase in DNA damage. A significant
increase in lipid peroxidation under UVA doses was
recorded. The variability in number and molecular
weight of proteins under exposure to UVA was
evident, reflecting some of the genetic and transcriptional
changes during exposure and development.

Many ultraviolet-A (UVA)-induced biochemical
and physiological changes are valid as
biomarkers using aquatic species for detection of the
degree of stress. Changes in the concentration and
activities of enzymes, such as glucose-6-phosphate
dehyderogenase (G6PDH), lactate dehyderogenase
(LDH), DNA damage and lipid peroxidation (LPO),
can be used as biomarkers to identify possible
environmental contamination in fish. This study
aimed to investigate the impact of UVA on the
activity of the selected enzymes, DNA damage and
LPO during early developmental stages of the African
catfish Clarias gariepinus. Embryo hemogenates were
used for measurements of G6PDH, LDH, DNA
damage and LPO concentrations and activities spectrophotometrically
at 37C. The normal ontogenetic
variations in enzyme activities, DNA damage and
LPO of the early developmental stages (24–168
h-PFS; hours-post fertilization stage) were studied.
There was a significant decrease in the activity of
G6PDH till 120 h-PFS. Then after 120 h-PFS, the
activity of such enzymes insignificantly increased
toward higher stages. The LDH activity was recorded
with a pattern of decrease till 96 h-PFS, followed by a
significant increase toward 168 h-PFS. The polynomial
pattern of variations in DNA damage and LPO
was also evident. The patterns of the enzyme activities,
corresponding DNA damage and LPO of the
early ontogenetic stages under the influence of three
different UVA doses (15, 30 and 60 min), were
recorded. The pattern of variations in G6PDH activity
in UVA-induced groups was similar to that of the
control group with variation in the magnitude of such
activity. In all treated groups, LDH activity decreased
till 96 h-PFS, then increased till 168 h-PFS. Within
each of the embryonic stages, the increase in UVA led
to a significant increase in DNA damage. A significant
increase in lipid peroxidation under UVA doses was
recorded. The variability in number and molecular
weight of proteins under exposure to UVA was
evident, reflecting some of the genetic and transcriptional
changes during exposure and development.

In the present work, the destructive effects of Ultraviolet-A radiation on the African Catfish, Clarias gariepinus was revealed in terms
of total protein, cholesterol, glucose, hemoglobin and erythrocytic indices, differential blood cell counting, heamatocrite, creatinine level,
Aspartic Amino Transferase, Alanine Amino Transferase and Alkaline Phosphatase. These destructive effects were also confirmed by
histopathological changes in liver, blood corpuscles and skin.

In the present work, the destructive effects of Ultraviolet-A radiation on the African Catfish, Clarias gariepinus was revealed in terms
of total protein, cholesterol, glucose, hemoglobin and erythrocytic indices, differential blood cell counting, heamatocrite, creatinine level,
Aspartic Amino Transferase, Alanine Amino Transferase and Alkaline Phosphatase. These destructive effects were also confirmed by
histopathological changes in liver, blood corpuscles and skin.

In the present work, the destructive effects of Ultraviolet-A radiation on the African Catfish, Clarias gariepinus was revealed in terms
of total protein, cholesterol, glucose, hemoglobin and erythrocytic indices, differential blood cell counting, heamatocrite, creatinine level,
Aspartic Amino Transferase, Alanine Amino Transferase and Alkaline Phosphatase. These destructive effects were also confirmed by
histopathological changes in liver, blood corpuscles and skin.

Aluminium is well known to inhibit plant elongation, but the role in this inhibition played by water relations remains
unclear. To investigate this, tobacco (Nicotiana tabacum L.) suspension-cultured cells (line SL) was used, treating them
with aluminium (50 mM) in a medium containing calcium, sucrose, and MES (pH 5.0). Over an 18 h treatment period,
aluminium inhibited the increase in fresh weight almost completely and decreased cellular osmolality and internal
soluble sugar content substantially; however, aluminium did not affect the concentrations of major inorganic ions. In
aluminium-treated cultures, fresh weight, soluble sugar content, and osmolality decreased over the first 6 h and
remained constant thereafter, contrasting with their continued increases in the untreated cultures. The rate of sucrose
uptake, measured by radio-tracer, was reduced by approximately 60% within 3 h of treatment. Aluminium also
inhibited glucose uptake. In an aluminium-tolerant cell line (ALT301) isogenic to SL, all of the above-mentioned
changes in water relations occurred and tolerance emerged only after 6 h and appeared to involve the suppression of
reactive oxygen species. Further separating the effects of aluminium on elongation and cell survival, sucrose
starvation for 18 h inhibited elongation and caused similar changes in cellular osmolality but stimulated the production
of neither reactive oxygen species nor callose and did not cause cell death. We propose that the inhibition of sucrose
uptake is a mechanism whereby aluminium inhibits elongation, but does not account for the induction of cell death