Biochemical Properties of α-Amylase from Midgut of Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) Larvae

Abstract

The lesser mealworm, Alphitobius diaperinus (Panzer), is the main insect pest in the poultry industry, thus causing serious damage to production. In this work, the properties of midgut α-amylase from larvae of A. diaperinus were characterized, and its in vitro activity to proteinaceous preparations from different cultivars of common bean (Phaseolus vulgaris) was determined, as well as the amylolitic activity of insects reared on different types of poultry diet. In order to establish some assay conditions, time course and enzyme concentration upon the reaction rate were determined. Product proceeded linearly with time, and the activity was directly proportional to the enzyme concentration. Banding patterns in mildly denaturing electrophoresis showed a single band with apparent molecular weight of 42 kDa. α-Amylase reached optimal temperature at 45°C and pH 5.0 as the optimal one. It maintained 34.6% of the activity after being kept at 60°C for 5 min, and 23%, after 60 min. However, at 80°C, only 14 and 6% remained after 5 and 60 min, respectively. The presence of Ca and Na ions decreased the enzyme activity at concentrations higher than 2 and 100 mM, respectively. The activity was significantly inhibited by some proteinaceous extracts from common bean cultivars, and it declined with increasing proteinaceous concentration. No significant difference was observed when the amylolytic activity was determined in A. diaperinus reared on different poultry diets, offered to broilers in the starter, grower, finisher, and layer phases.

Biochemical characterization and overexpression of an α‐amylase (BmAmy) in silkworm, Bombyx mori

“…In lesser mealworm, a 42-kDa α-amylase showed optimal activity at 45 C and pH 5.0. Moreover, previous results showed that the activity of α-amylase in lesser mealworm can be significantly inhibited by some proteinaceous extracts from bean cultivars (Cruz et al, 2018). The structure of α-amylase (CcAmy) in Callosobruchus chinensis was shown to be different from TcAmy in Tribolium castaneum, although they both belong to Coleoptera (Channale et al, 2016).…”

“…Domain B contains several α-helices and β-folded chains that are important components of the active site, whereas domain C is formed by antiparallel β-sheets that are thought to protect the stability of hydrophobic amino acids in the catalytic centre (MacGregor et al, 2001). Since digestive enzymes exhibit potential use as molecular targets for pest control, α-amylases are widely studied in different insects (Ashouri & Farshbaf Pourabad, 2020;Celinska et al, 2015;Channale et al, 2016;Cruz et al, 2018). In lesser mealworm, a 42-kDa α-amylase showed optimal activity at 45 C and pH 5.0.…”

Insect α-Amylases and Their Application in Pest Management

“…The optimum temperature for maintaining α-amylase activity in insects is between 30 • C and 60 • C, and α-amylase activity drops sharply when the temperature reaches above 60 • C. A study showed that α-amylase from the midgut of Alphitobius diaperinus (Coleoptera: Tenebrionidae) larvae reached an optimal temperature of 45 • C. It maintained 34.6% activity after being kept at 60 • C for 5 min, and activity dramatically decreased to 23% when placed at 80 • C for 1 h. The presence of high levels of Ca 2+ (2 mM) and Na + (100 mM) ions was also shown to decrease enzyme activity [47]. The H. armigera α-amylase optimum temperature is 50 • C [43].…”

Characteristics of lesser mealworm Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae)

“…A. diaperinus pierwotnie pochodzi z rejonów tropikalnych Afryki (10,39). Owad popularnie występuje w kurnikach (7,17,31,37,47) zwłaszcza, gdy kurczęta utrzymywane są na ściółce (20,36). Wysoka temperatura powietrza podczas odchowu kurcząt, zaleganie pomiotu kurzego, wysoka wilgotność względna powietrza oraz wilgotna ściółka -są to czynniki, które stwarzają korzystne warunki do rozwoju chrząszczy przez cały rok (4).…”