Biochemical characterization of digestive α-amylase, α-glucosidase and β-glucosidase in pistachio green stink bug, Brachynema germari Kolenati (Hemiptera: Pentatomidae)

Samar Ramzi,Vahid Hosseininaveh 한국응용곤충학회 2010 Journal of Asia-Pacific Entomology Vol.13 No.3

The pistachio green stink bug, Brachynema germari, has 3–5 generations per year and causes severe damages to pistachio crops in Iran. Physiological digestive processes, such as digestive carbohydrases, can be used to design new strategies in IPM programs for controlling this pest. The enzyme α-amylase digests starch during the initial stage of digestion. Complete breakdown of carbohydrates takes place in the midgut where α- and β-glucosidic activities are highest. Alpha-amylase and α- and β-glucosidase activities were found in the midgut and salivary glands of pistachio green stink bug adults. Overall enzyme activities were significantly higher in the midgut than in salivary glands. The highest α-amylase and α- and β-glucosidase activities were in section v3, whereas the lowest activities were in section v4. Vmax was higher and Km was lower in the midgut than in the salivary glands for these enzymes. In the pistachio green stink bug, the optimal pH was pH 5–6.5 and the optimal temperature was 30 °C to 35 °C for these enzymes. Alpha-amylase activity in the midgut and salivary glands decreased as the concentrations of MgCl2, EDTA and SDS increased. Enzyme activities in both midgut and salivary glands increased in the presence of NaCl, CaCl2, and KCl. NaCl had a negative effect on alpha-amylase extracted from salivary glands.

Comparison of glutathione S-transferase and general esterase in two bugs, Eurygaster integriceps Puton (Heteroptera: Scutelleridae) and Brachynema germari Kolenati (Heteroptera: Pentatomidae)

Samar RAMZI,Ali Reza BANDANI1,Arash ZIBAEE,권오석 한국곤충학회 2009 Entomological Research Vol.39 No.4

Glutathione S-transferases (GSTs) and general esterases play important roles in the detoxification of many substances including allelochemicals from plants and chemical pesticides. In this study, to determine the feeding status and effects of agronomical practices on GST and general esterase, two bug species, Eurygaster integriceps and Brachynema germari, were selected with differences in these cases. GST and general esterase responses varied when switching from 1-chloro-2,4-dinitrobenzene (CDNB) and a-naphtyl to 1,2-dichloro-4-nitro-benzene (DCNB) and b-naphtyl in E. integriceps and B. germari, respectively. The activities of GST and esterase by using CDNB and a-naphtyl were higher than that of DCNB and b-naphtyl for both insects. It was shown that the optimal pH for GST and general esterase activity varied between pH 5.5 and 6. While the Michaelis constant (Km) value related to E. integriceps toward CDNB and a-naphtyl was lower than Km for B. germari, Km values calculated for E. integriceps toward DCNB and b-naphtyl corresponding to those related to A. hejeri were similar to CDNB and a-naphtyl values. The maximal reaction velocity (Vmax) values related to E. integriceps for both substrates (CDNB and a-naphtyl) were always higher than those from B. germari and showed significant differences. At the basement of the native-PAGE electrophoresis, five bands were observed in for GST and three were visualized for B. germari, with a large, darker band for E. integriceps in the case of esterases. Studies on the detoxification enzymes of herbivores should be undertaken to determine accurately the effect of the host plants on the organisms eating them, particularly in terms of biochemical and ecological advantages.

Effects of Citrullus colocynthis agglutinin on intermediary metabolism of Ectomyelois ceratoniae Zeller (Lepidoptera: Pyralidae)

Samar Ramzi,Ahad Sahragard,Arash Zibaee 한국응용곤충학회 2014 Journal of Asia-Pacific Entomology Vol.17 No.3

In the current study,we examined the effects of Citrullus colocynthis agglutinin (CCA) on the intermediary metabolismofEctomyelois ceratoniae larvae as a means of determining effectiveness of the lectin in pest control. Larvaewere fed on control diets and diets containing CCA (2%) for 24 and 48 h. The activities of digestive α-amylase andgeneral proteases significantly decreased in the larvae fed on the CCA diet, but no statistically significant changeswere found in the case of TAG-lipase. Meanwhile, the activities of all specific proteases, except aminopeptidase,changed in the treated larvae for all time intervals. The activity of alanine aminotransferase significantly decreasedin the treated larvae but the activities of aspartate aminotransferase and γ-glutamyl transferase increased24 h post-feeding on the CCA diet. The activity of aldolase decreased 48 h post-feeding but lactatedehydrogenase (LDH) showed inverse results at the same time interval. The activities of acid phosphatase(ACP) and alkaline phosphatase (ALP) decreased 48 h post-feeding for ACP and at both time intervals for ALP. The amount of high-density lipoprotein (HDL) showed no statistical differences between control and CCA-fedlarvae, but the amount of low-density lipoprotein (LDL) significantly increased in the CCA-fed larvae at bothtime intervals. The amount of protein increased in the larvae fed on the CCA diet, but the amounts of glycogenand triacylglycerol significantly decreased at both time intervals. Results of the current study clearly revealthat ingestion of CCA significantly influences the activities of digestive enzymes and disrupts the intermediarymetabolism of E. ceratoniae larvae. Further studies on genetic engineering of CCA to provide resistant varietiesmight open a new avenue for safe and efficient control of the pest.

Competition and overlap of Oryzaephilus surinamensis and Plodia interpunctella populations under condition of stored date fruits

Latifian Masoud,Jalili Moghadam Maryam,Ramzi Jahromi Samar 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.1

Plodia interpunctella and Oryzaephilus surinamensis are found in food storehouses including dates and palm storages. The current study aimed to determine competition and overlap potentials of the two pests of date fruits. Time series models were used to study two species populations and logistic growth model to estimate the effect of density of the species. The results revealed the environmental capacities of O. surinamensis and P. interpunctella were 433 and 1610 (maximum number per 20 g), respectively, and the population growth rates (r) were 1.2 and 1.3, respectively. Ecological balances of the two species were close to each other from the first to the third week. The population of O. surinamensis decreased in the fourth week of the competition. The highest population balance of the two species was in the 14th week. The potential of exploitable ecological niches (e ij ) and the amount of non-exploited ecological niches by any species (z ij ) for O. surinamensis was higher than for P. interpunctella from the 8th week untill the end of sampling period. The overlap of ecological niches in the two species (D) ranged from 0.94 to 1, indicating a complete overlap of temporal activity in the two populations on date palm. The current results of this study can be used by integrated pest management specialists. Information over the effects of species competition on population dynamics and their coexistence can be used to predict population status and to adopt simple pest control methods.

Characterization of α-amylase in the midgut and the salivary glands of rice striped stem borer, Chilo suppressalis Walker (Lepidoptera: Pyralidae)

Arash Zibaee,Ali Reza Bandani,Maryam Kafil,Samar Ramzi 한국응용곤충학회 2008 Journal of Asia-Pacific Entomology Vol.11 No.4

The rice striped stem borer, Chilo supprressalis, is a destructive pest of rice that was introduced to Iran in 1973 and has since become widely distributed. Amylases are hydrolytic enzymes that catalyze the hydrolysis of the α-D-(1,4)-glucan linkage in glycogen and other related carbohydrates. Laboratory-reared 4th stadium larvae were randomly selected; the midgut and the salivary glands were removed by dissection under a dissecting microscope and α-amylase activity was assayed using the dinitrosalicylic acid procedure. The activity of α-amylase in the midgut and salivary gland were 0.06 and 0.036 μmol/min/mg protein, respectively. The optimal pH and temperature for α-amylase were 9 and 35–40 °C, which is consistent with reports of other lepidopteran insects. The enzyme activity was inhibited by addition of NaCl, KCl, MgCl2, Urea, EDTA, and SDS. CaCl2 enhanced enzyme activity. Ca2+ ions also had inhibitory effects on glucosidase activity. Plant amylase inhibitors play important role against insect pests. Hence, the characterization of digestive enzymes and the examination of inhibitors on enzyme activity could be useful in tackling of insect pests. The rice striped stem borer, Chilo supprressalis, is a destructive pest of rice that was introduced to Iran in 1973 and has since become widely distributed. Amylases are hydrolytic enzymes that catalyze the hydrolysis of the α-D-(1,4)-glucan linkage in glycogen and other related carbohydrates. Laboratory-reared 4th stadium larvae were randomly selected; the midgut and the salivary glands were removed by dissection under a dissecting microscope and α-amylase activity was assayed using the dinitrosalicylic acid procedure. The activity of α-amylase in the midgut and salivary gland were 0.06 and 0.036 μmol/min/mg protein, respectively. The optimal pH and temperature for α-amylase were 9 and 35–40 °C, which is consistent with reports of other lepidopteran insects. The enzyme activity was inhibited by addition of NaCl, KCl, MgCl2, Urea, EDTA, and SDS. CaCl2 enhanced enzyme activity. Ca2+ ions also had inhibitory effects on glucosidase activity. Plant amylase inhibitors play important role against insect pests. Hence, the characterization of digestive enzymes and the examination of inhibitors on enzyme activity could be useful in tackling of insect pests.