This paper analyzes the influence of infrared radiation (IR) on regeneration, after autotomy of limb buds of Neohelice granulata and consequently the time molt. Eyestalks were ablated to synchronize the start of molt. Afterward, animals were autotomized of five pereopods and divided into control and irradiated groups. The irradiated group was treated for 30 min daily until molt. Limb buds from five animals of days 4, 16 and 20 were collected and histological sections were made from them. These sections were photographed and chitin and epithelium content measured. Another group was made, and after 15 days limb buds were extracted to analyze mitochondrial enzymatic activity from complex I and II. The irradiated group showed a significant reduction in molt time (19.38+/-1.22 days) compared with the control group (32.69+/-1.57 days) and also a significant increase in mitochondrial complex I (388.9+/-27.94%) and II (175.63+/-7.66%) in the irradiated group when compared with the control group (100+/-17.90; 100+/-7.82, respectively). However, these effects were not accompanied by histological alterations in relation to chitin and epithelium. This way, it was possible to demonstrate that IR increases complex I and II activity, reduces the time molt and consequently increases the appendage regeneration rate.
Declining bee populations diminish pollination services, damaging plant, and agricultural biodiversity. One of the causes of this decline is the use of pesticides. Pesticides with glyphosate as an active ingredient are among the most used pesticides worldwide, being the most used in Brazil. This study determined the 24 and 48 hours LD50 (median lethal dose) of the herbicide glyphosate by ingestion, identi ed sublethal doses, and investigated its effects on the locomotion and behavior of Tetragonisca angustula workers. The LD50 found indicates that glyphosate is highly toxic to T. angustula. The doses applied, including concentrations found in nature and recommended dosage, caused death, motor changes (decreased speed and tremors), excessive self-cleaning, and disorientation (return to light and stop). These results suggest that this herbicide can negatively affect the pollination activity of T. angustula. Toxicity and sublethal effects evaluation of pesticides on bees contributes to a better understanding of the harmful effects on hives and to adopt strategies to reduce intoxication.
To determine the chronic skin effects caused by the interaction of infrared and ultraviolet B radiations, male Rattus norvegicus (Wistar) (2 months old) were exposed for 15 days to infrared radiation (600-1500 nm, with a peak at 1000 nm, n = 12) for 30 min (1080 J cm(-2) ) (IRo); to ultraviolet B radiation (peak emission at 313 nm, n = 9) for 90 min (55.08 J cm(-2) ) (UVB); to infrared radiation followed after 90 min by ultraviolet B (n = 6) (IRUVB) and to ultraviolet B followed after 90 min by infrared radiation (n = 9) (UVBIR). Skin samples were collected and histopathological analysis showed the presence of acanthosis, parakeratotic and orthokeratotic hyperkeratosis, intraepidermal pustules, keratin pearls, detachment of epidermis, collagen necrosis, inflammatory infiltrate, vasodilation, basal cell vacuolization and superficial dermis degeneration both in UVB and UVBIR treatments. IRUVB animals showed the same characteristics as above except for parakeratotic hyperkeratosis, keratin pearls and superficial dermis degeneration. To conclude, infrared radiation exposure after ultraviolet B irradiation increases skin damage without protecting the tissue, while infrared radiation exposure before ultraviolet B irradiation showed a protective effect against ultraviolet skin damage.
Declining bee populations diminish pollination services, damaging plant, and agricultural biodiversity. One of the causes of this decline is the use of pesticides. Pesticides with glyphosate as an active ingredient are among the most used pesticides worldwide, being the most used in Brazil. This study determined the 24 and 48 hours LD50 (median lethal dose) of the herbicide glyphosate by ingestion, identified sublethal doses, and investigated its effects on the locomotion and behavior of Tetragonisca angustula workers. The LD50 found indicates that glyphosate is highly toxic to T. angustula. The doses applied, including concentrations found in nature and recommended dosage, caused death, motor changes (decreased speed and tremors), excessive self-cleaning, and disorientation (return to light and stop). These results suggest that this herbicide can negatively affect the pollination activity of T. angustula. Toxicity and sublethal effects evaluation of pesticides on bees contributes to a better understanding of the harmful effects on hives and to adopt strategies to reduce intoxication.
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