Urbanization has the potential to dramatically affect insect populations worldwide, although its effects on pollinator populations are just beginning to be understood. We compared the immunocompetency of honey bees sampled from feral (wild-living) and managed (beekeeper-owned) honey bee colonies. We sampled foragers from feral and managed colonies in rural, suburban, and urban landscapes in and...

Clip domain serine protease homologs (SPHs) are positive and negative regulators of Anopheles gambiae immune responses mediated by the complement-like protein TEP1 against Plasmodium malaria parasites and other microbial infections. We have previously reported that the SPH CLIPA2 is a negative regulator of the TEP1-mediated response by showing that CLIPA2 knockdown (kd) enhances mosquito resist...

Honey bees (Apis mellifera) have become a model system for studies on the influence of genetic diversity on disease. Honey bee queens mate with a remarkably high number of males-up to 29 in the current study-from which they produce a colony of genetically diverse daughter workers. Recent evidence suggests a significant benefit of intracolony genetic diversity on disease resistance. Here, we exp...

Levels of phenoloxidase (Po), trypsin and lysozyme activities were determined following 48 hours exposing freshwater crayfish (Pontastacus leptodactylus) weighing 59.8&plusmn;3.4g to different low pH values of 6.5, 5.5, 4 and 2.5 at 20-23˚C. Significant decrease were found (p<0.01) in levels of Po and trypsin activities in crayfish haemocyte lysate supernatant (HLS) at pHs 5.5 and 4 compared to...

Phenoloxidase (Po) activity was measusred spectrophotometrically in serum, plasma and haemocytes (HLS) of the freshwater crayfish (Pontastacus leptodactylus). The highest activity was found in HLS suggesting that the haemocytes are the major source of the Po or its proform prophenoloxidase (proPO) in crayfish. Furthermore, the enzyme activity in serum samples was reduced after freezing the samp...

Crustacean phenoloxidase (PO) and hemocyanin (Hc) are classified as type 3 copper proteins. PO catalyzes the oxidation of mono- di-phenol compounds, which is rate-limiting step melanization, while Hc generally functions a dioxygen-transporting protein in hemolymph arthropods. To date, many studies have shown activity Hc, inspired by their structural similarity. Here, source crustaceans was re-e...

The cellular and humoral immune reactions in haemolymph of the wax moth Galleria mellonella larvae naturally injected by venom of ectoparasitic wasp Habrobracon hebetor were analyzed. A strong decline of phenoloxidase (PO) activity in the haemolymph and the number of haemocytes with PO activity of envenomated wax moth was observed. In addition, it has been shown that the rate of capsule melaniz...

39 Phenoloxidase (PO) is believed to be a key mediator of 40 immune function in insects and has been implicated both in 41 non-self recognition and in resistance to a variety of 42 parasites and pathogens, including baculoviruses and para43 sitoids. Using larvae of the Egyptian cotton leafworm, Spo44 doptera littoralis, we found that despite its apparent impor45 tance, haemolymph PO activity va...

A gene (yacK) encoding a putative multicopper oxidase (MCO) was cloned from Escherichia coli, and the expressed enzyme was demonstrated to exhibit phenoloxidase and ferroxidase activities. The purified protein contained six copper atoms per polypeptide chain and displayed optical and electron paramagnetic resonance (EPR) spectra consistent with the presence of type 1, type 2, and type 3 copper ...